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6th EAGE Saint Petersburg International Conference and Exhibition
- Conference date: April 7-10, 2014
- Location: Saint Petersburg, Russia
- Published: 07 April 2014
1 - 100 of 174 results
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Detailed Geological Modeling of Precambrian Fractured Reservoirs and Estimation of Their Oil Reserve Properties
Authors V.V. Kharakhinov, S.I. Shlenkin, V.A. Zereninov, O.M. Koulishkina, M.V. Berin and O.V. RydSummaryThe paper describes technology of fractured carbonate reservoirs geological modeling based on integrated analysis of 3D seismic and well data. This technology allows us to predict the most productive zones in the reservoir and to use this information for the oil field development.
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Integrated Approach to the Development of Geological Models of Fractured Carbonate Reservoirs in the Timan-Pechora
SummaryThe paper describes an integrated approach to geological modeling of complex carbonate reservoirs (of fracture and fracture-pore type) in Timano-Pechora province. This approach allows us to refine the structure and properties of oil-and-gas deposits in the middle Ordovician – early Devonian strata.
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Fine Structure Reconstruction of Cavernousporous Reservoirs Based on Scattered Wavefield Interpretation
Authors A.S. Merzlikina, V.S. Nefedova, V.A. Pozdnyakov, A.A. Tuzovskiy, V.A. Tcheverda and V.V. ShilikovSummaryThis paper presents the original technique of fine structure reconstruction, based on the scattered wavefield processing. In particular, the implementation of this technique to cavernous-porous reservoirs is discussed. The main features of this approach are: full-scale numerical simulation; object-oriented migrational transformations; integral operators for true-amplitude wavefield continuation
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The Special Method of Processing of Scattered Waves and Its Use in Eastern Siberia
Authors A.A. Kozyaev, K.O. Matrosov, A.S. Merzlikina and V.V. ShilikovSummaryIn carrying out such expensive works as seismic survey, it is advisable to try to extract the maximum benefit from it , for this reason , the main trend in modern seismic survey is to try to increase the volume of useful information extracting from raw data. One way to increase this volume is the study of the scattered wave field component, which carries information about the internal structure of the study area. For the selection of scattered component from full seismic field energy, is proposed to use a special technology of focusing transformations. This report presents an example of application of this technology in one of the licensed areas of Eastern Siberia. The main feature of this area is the presence of a dense network of small blocks faulting on the background of regional faults. As well to increase the signal / noise ratio was used a special processing of the results. During the work were identified interesting anomalies, which are described at the report. As a result were obtained the schemes of energy distribution of the scattered waves, that allow identify in the study area the most promising areas for hydrocarbon exploration.
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Uncertainty Quantification with Application of Distance Metric in Naturally Fractured Reservoirs Modelling
Authors K. Gopa, V. Demyanov, M. Ahmed Elfeel and D. ArnoldSummaryCharacterization and modelling of naturally fractured reservoirs (NFR) is usually complicated with very high degree of heterogeneity and uncertainty related to fractures. A commonly used framework for uncertainty estimation such as Monte-Carlo modelling is straightforward but in case of NFR is highly time-consuming as it requires generation of a large number of realizations and their flow simulation. We propose a more efficient method in terms of time cost, for uncertainty estimation in NFR flow performance. The idea of the method is to select a subset of reservoir models reflecting the same uncertainty range in flow response as the full set. The large set of NFR models is generated capturing the variability of fractures parameters. We calculate Euclidean distance between flow responses obtained from results of fast but not accurate flow simulations and apply multidimensional scaling to map realizations into some space representing spatially their uncertainty. Grouping similar realizations in clusters we find those realizations which are located in their centers and hence the most different. Once the most diverse realizations are obtained, an accurate flow simulation is run and uncertainty is quantified using only selected small subset of realizations. We demonstrate the workflow on the synthetic but realistic example.
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Fractured Basement Characterization and Its Relation to Production Zone Potential in Southern Sumatra Basin, Indonesia
Authors A.B.S. Samudra, S. Sugiri and M.W. WahyudinSummaryPT. PERTAMINA EP in 2009 drilled AXL-1 in South Sumatra Basin and discovered oil in Pre-Tertiary Quartzite at AXL Area, South Sumatra, Indonesia. The well was drilled and reached Quartzite basement at 2254 mMD with no indication of hydrocarbon based on gas reading but after 204 m, total gas suddenly reached 1401 unit with hydrocarbon indication from nC1 up to nC5 at 2458 mMD and subsequently crude oil was bleeding in the shale shaker and flowed oil up to 320 BOPD. Geological and Geophysical analysis were conducted and modeled to characterize fractured basement reservoir in the Pre-Tertiary rocks in the AXL area related to its production zone potential. Fractured basement lithology in the AXL area is quartzite with volcanic mineral exist and minor secondary mineral which indicated fluid flow in the reservoir. Faults and micro-faults were observed and demonstrate dominant NE-SW strike with abundant conductive fractures with strike dominant NE-SW with minor NW-SE. Based on integrated fracture analysis in AXL area, production hydrocarbon potential zone along the basement section maybe related to multiple fracture orientation which build a fracture network for fluid to flow and it is related to the fault system in the Pre-Tertiary basement rock.
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Analysis of Anisotropy Parameters of Fractured Carbonate Reservoir
Authors Y.A. Alkhimenkov and I.O. BayukSummaryRecently unconventional reservoirs attract more and more attention in prospecting geophysics. Unconventional reservoirs often exhibit anisotropic physical properties due to specific features of their microstructure and texture. In the work a theoretical modeling of effective elastic properties of such a reservoir - fractured carbonate rock of low porosity - is considered. Commonly fractures in the reservoirs are sub-vertical which leads to HTI symmetry of the rock. Elastic constants of the carbonate reservoirs are calculated with the help of different approaches of the effective media theory: generalized singular approximation, Hudson’s model and Eshelby-Cheng model. The purpose of this work is estimation and analysis of small-anisotropy Thomsen’s parameters of fractured carbonate reservoir, examination of applicability of the parameters to predict elastic wave velocities in different directions and comparison of the results provided by different theoretical approaches.
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Fracture Imaging by Weighted Summation of Multi-component Data and Image Spectrum Analysis
Authors M. Protasov, V.A. Tcheverda and G.V. ReshetovaSummaryAn approach to seismic imaging of fractures by multicomponent surface data is presented and discussed. It is based on a specific imaging procedure, which consists in a weighted summation of multicomponent multishot/multioffset data. These weights are computed by tracing a specially chosen Gaussian beams. In order to get image of fractures these beams are taken in a way forming so called selective images (Pozdnyakov and Tcheverda, 2006; Protasov and Tcheverda, 2011). Their geometry provides suppression of regularly reflected waves and, thus, emphasizes the presence of small-scale heterogeneities that give rise to diffracted/scattered waves. Additionally spectral removal is applied for more essential suppression of regular reflections footprint.
Numerical experiments with synthetic data set computed for the typical seismogeological model of Yurubcheno-Tokhomskoye area are presented and discussed.
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Low Frequency Anomalies below Gas Reservoirs - Possible Explanation
Authors G.M. Goloshubin and E. ChabyshovaSummaryWe consider a possible explanation of the seismic low frequency anomalies using converted Fast-Slow- Fast P- waves in a thinly layered porous permeable fluid-saturated medium. Wave propagation in highly interbedded permeable gas reservoirs suggests significant and anomalous amount of mode conversions between Fast and Slow P-waves, which may be observed from surface seismic reflection data. Those converted P-waves experience high frequency dependent attenuation. In case if some converted waves propagated only a short fraction of their travel paths as Slow P-waves they will be notably delayed and attenuated relative to Fast P-wave reflections. A model of sandstone reservoir with typical parameters is used to estimate time delays of the converted Fast-Slow-Fast P-waves and their influence into total reflected P-waves energy at seismic frequencies.
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Introducing Ji-Fi - Joint Impedance & Facies Inversion
Authors M.A.C. Kemper, K. Waters, A. Somoza, A. Pelham and A. KozhenkovSummaryIn this paper we introduce Ji-Fi, a new Joint Impedance & Facies Inversion system, which gives a significant increase in quality over model-based Simultaneous Inversion, because it incorporates the correct physics! We first review Simultaneous Inversion, then introduce Ji-Fi and compare one against the other, first with a wedge model and then using a case study.
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Joint Inversion of Multi-type Geophysical and Geochemical Data for Hydrocarbon Systems Exploration at Sea Shelf
SummaryThe possibilities of the joint inversion of the modern multi-type geophysical (3D seismic, gravity & magnetic and electromagnetic) and geochemical data sets are demonstrated for the purposes of the oil-andgas- bearing capacity estimation and geological risk assessment in the sea shelf areas where no well logging information and other priory constraints are available. Methods, algorithms and software are developed for the construction of the coordinated 3D models of the media physical properties. The utilisation of the density model (as obtained from gravity data) as the low-frequency model for seismic inversion is suggested and demonstrated. It is shown that the joint inversion of seismic and magnetic data helps to authentically differentiate between carbonate reef and buried volcano structures. The regular links are ascertained between bottom sediments hydrocarbon gases concentration and structural and tectonic characteristics of the sub-surface that become apparent in seismic attributes. The method for the qualitative estimation of the hydrocarbon reservoir depth is developed based on the modelling of the gases filtration from reservoir to the surface. The principles are suggested for the recognition and prospectivity estimation of the oil and gas complexes from the joint analysis of the different data types.
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Petrophysical Investigation for Selecting Seismic Inversion Type (Yamal Gas Condensate Field Case Study)
Authors A.A. Popravko, T.F. Sokolova and V.I. KuznetsovSummaryNowadays seismic inversion techniques are widely used for quantitative reservoir characterization. The petrophysical basis for seismic inversion is data of the rock elastic properties which are a result from theoretical and empirical modeling namely Rock Physics. Completeness and quality of the initial well log data are crucial for building reliable reservoir model based on seismic data. The selection of inversion techniques strongly depend on acoustic properties in a target interval. This analysis was performed in multidimensional space of density and compression shear velocities. This paper shows the Rock Physics modeling results for inversion type selection estimation in order to build 3D model of gas-condensate saturated.
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Reservoir Properties Characterization Using Simultaneous AVO/AVA Inversion at the Exploration Stage
Authors I. Iakovleva, A. Popravko, P. Ponomarenko and Z. GazaryanSummaryInvestigation of new exploration objects assotiated with number of difficulties. The main problem of this study is the presence of limited information both seismic and well logs. In this case for reservoir properties prediction seismic attributes analysis and AVO analysis are typically used. However, application of seismic inversions, even in early stages of the fields study, allows to get additional information about reservoir properties.
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Consideration of Velocity Anomalies During Seismic Inversion
Authors O. Belashov, G. Lecant and S. BaptisteSummaryБлагодаря повышению соотношения сигнал/шум и расширению частотного спектра, результаты инверсии обладают большей разрешающей способностью. Оптимизация процесса увязки сейсмических и скважинных данных мы получаем наиболее достоверное контроль над результатами инверсии
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The Problem of Incomplete Prior Information in Stochastic Inversion
More LessSummaryOne of the main problems that always remains unresolved within the framework of the inverse problem is the prior information. In this pages represent analysis of the problem that arises when using stochastic inversion on the object wich, not described of prior information, but is clearly associated with a geological body by seismic data. The existence of complex geological objects with indirect morphological features, as well as the development of methods for their isolation allows a fresh look at the problem of prior information in the framework of solving the inverse problem and the character of seismic information.
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Comparison of Different Approaches for Seismic Driven Geostatistical Modeling
More LessSummaryThe importance of using all available information for seismic driven geostatistical modeling, advantages of sesimic driven geostatistical modeling namely geostatistical inversion with multi-level discrete properties models is demonstated in this paper.
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Terrigenous Reservoir Structure Elaboration and Risk Assessment Using Geostatistical Modeling Controlled by Seismic Data
Authors E. Zadorina, V. Bykov, L. Markelova, I. Grigorenko and M. KrylovaSummaryThis article demonstrates using geostatistical modeling controlled by seismic data as one of the best way to predict reliable reservoir properties distribution under the conditions of its significant lateral variations wherein the thickness is quite small. Also it shows the realizations ranking and the initial geological model updating by separating one more prospecting layer. What is more the risk assessment has been done for different uncertainty origin.
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Object Modeling and Prediction of Well Rates in Tide Domintated Delta Reservoir, Field N, Russia
Authors S.A. Sizykh, V.S. Rukavishnikov, A.S. Bochkov and B.V. BelozerovSummaryField N is situated in Yamal peninsula in Western Siberia. From 19 productive layers, J3-4 layers are the most important for consideration as they contain significant amount of STOIIP. On base of complex analysis of core data and paleogeography, depositional environment of J3-4 layers was defined as tide dominated delta. Sandbodies are presented by channel facies and also by interdistributary facies, formed by levees and crevasse splays. Qualitative and quantitative analysis of log data allowed creation of input data for geological model. 3D facies model was obtained using combination of object modeling and sequential indicator simulator methods. Properties in model were obtained with use of random simulation function and various recalculations. Geological model was transformed into simulation model. Uncertainties, related to sandbody dimensions, model realizations and sandbody distribution in tested well were evaluated using numerous realizations of geomodel. Cumulative oil recovery and rates were evaluated for horizontal and vertical wells, using P10 P50 P90 values.
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Methods for Assessing the Quality of Seismogeological Models
By A. NikolaevSummaryThe report describes a systematic approach to the construction of stochastic geological and hydrodynamic models based on the results of seismic inversion. Using the results of stochastic inversion can improve the quality of the geological model , giving an idea of areal and volumetric distribution of permeability and porosity of the formation. But especially important to determine the criteria for the presence of the reliability of the geological model. Such criteria , in our opinion may make the data field development , that is, to assess the validity seismogeological model should build a hydrodynamic model and to evaluate the convergence of the calculated and actual performance. Well the advantages of such an approach to modeling manifest in the performance of integrated projects , where the inversion results fall into the geological model, which becomes the basis of the filter model.
Our company has accumulated experience in building projects stochastic geological and hydrodynamic models based on the results of seismic inversion.
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Rapid Determination of Optimum Wettability Alteration Radius for Gas-condensate Reservoirs
Authors S. Aghabozorgi Nafchi and A. KhormaliSummaryThe optimization in wettability alteration process is limited to the work of Zoghbi et al. (2010) and Fernandez et al. (2011). Although there are few investigations on the effect of treatment radius (Zoghbi et al, 2010), there is no reported data for the optimum wettability radius determination. In this paper a rapid method for prediction of optimum radius is presented and the effect of the wettability alteration radius on the cumulative gas production is investigated. A simulator has been developed based on the method suggested by Mott (2002) and the accuracy the simulator is verified by Eclipse (Schlumberger) software for different compositions. This developed simulator has been used for calculating the capillary numbers near the wellbore region before wettability treatment. The calculated capillary numbers are plotted verses a function of radius, based on the developed theory suggested by the authors, that relates the capillary number to radius. This method was applied for 27 synthetic reservoirs and the results were used for determination of optimum treatment radius, above which the increase in gas production is not significant. The optimum treated radius determined by this rapid method was in a good agreement with optimum wettability alteration radius based on the compositional simulations.
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Petrophysical Properties Evaluation of Heterogeneous Gas Sandstone Reservoirs with NMR Logging Data
By G.M. HamadaSummaryPetrophysical evaluation of heterogeneous gas sandstone reservoirs is one of the most difficult problems. These reservoirs usually produce from multiple layers with different permeability and complex formation, which is often enhanced by natural fracturing. Therefore, using new well logging techniques like NMR or a combination of NMR and conventional open hole logs, as well as developing new interpretation methodologies are essential for improved reservoir characterization. Nuclear magnetic resonance (NMR) logs differ from other conventional logs. Integration of NMR logs, other open hole logs and SCAL minimizes uncertainties in the determination of formation porosity, permeability and capillary pressure curve.
This paper concentrates on determination of three petrophysical parameters of heterogeneous gas sand reservoirs; 1) Determination of DMR porosity, ΦDMR, it is deduced from NMR porosity and density porosity, 2) NMR permeability, KBGMR, it is based on the dynamic concept of gas movement and bulk gas volume in the invaded zone and 3) Capillary pressure, it is derived from relaxation time T2 distribution.
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Multi-scale Uncertainty Assessment for Geostatistical Seismic Inversion
Authors L. Azevedo, V. Demyanov, S. Focaccia and A. SoaresSummaryDue to the intrinsic nature of seismic inverse problems there is always uncertainty related with the best-fit inverse model. Traditional geostatistical seismic inversion approaches are able to account the uncertainty related with the stochastic simulation algorithms that are used as part of the inverse methodology for the model perturbation. However, they assume stationarity and no uncertainty related with large scale geological parameters represented for example by the spatial continuity pattern and the prior probability distribution of the property to invert as estimated from well-log data. We propose a multi-scale uncertainty assessment for traditional iterative geostatistical seismic methodologies by integrating stochastic adaptive sampling and Bayesian inference to tune the variogram ranges and the prior probability distribution of the property to invert within the inverse workflow. The application of the proposed methodology to a challenging synthetic dataset showed a good convergence of the inverted seismic towards the recorded one while the local and global uncertainty were jointly assessed.
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Creation of Vch Geological Formation Model of Verhnechonskoe Field on the Basic of Stochastic Inversion
By M.V. OsipovaSummaryThe main object of exploitation of Verkhnechonskoye field is VCh1 productive object. It is characterized by complex geological structure, a high lateral heterogeneity of terrigenous reservoir. Besides pores is salted by halite that has a significant impact both on the reservoir properties, and on the process of reservoir development. Therefore, the forecast methods of reservoir salinization development areas are very important. This problem is solved using stochastic inversion in the present work. The results of this type of seismic data interpretation form the basis of the Vch geological formation model. As a results we received
- the maps of reservoir net pay by regression relations between 2D maps of elastic properties and average value of net pay by well log interpretation results;
- Maps of salted non-reservoir thickness by means of vertical stack of geological model cells for which “salted non-reservoir” lithotype is determined
- Contour of massive salt thickness distribution that coincides with the zone of sporadic reservoir distribution specifies the boundaries of deposits distribution
- For the first time various gas oil contacts of the deposits were justified in the central and eastern part of the polygon.
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Reservoir Heterogeneity Influence on Hard-torecover Reserves Development - A Case Study of Achimov Fm, Vingapur Field
Authors A. Kondratyev, V. Rukavishnikov and L.N. ShakirzyanovSummarySimulation model calculation is a base method that used for the efficiency of development strategy calculations it is necessary to design geological and simulation models within which are defined reservoir properties and heterogeneity.Estimation of influence on reservoir properties of various kinds of geological uncertainties will allow defining more effective development strategy.
Achimov Formation of Vingapur Oil Field was considered in current study the Northern part field nowadays is quite attractive for the development of this formation. The aim of work was complex investigation of petrophysical properties for the purpose of it prognosis across the field and the effect of geologic uncertainties on production assessment. On the first step was studied the western part of the field where core data are available, next was developed algorithm for the properties prognosis and eventually was constructed geologic and reservoir simulation models for the investigation of the effect of geologic uncertainties in Northern part. Petrophysical model of the reservoir where for the evaluations was applied method of Rock Types identification, in addition to this, Hydraulic Flow unit approach was also employed, that makes possible reservoir properties estimation in less explored areas of the field where core has not been retrieved.
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Cyclicity, Geological Modeling and Reservoirs Characterization in NE Offshore Nile Delta (Ha’py Field - Case Study)
Authors N. Moustafa Amer, M. Darwish, A. El Barkooky and E. SharfSummaryA detailed study of the Ha’py Field area is preformed to build up a reservoir geological model based on lithofacies analyses of core and ditch cutting samples supported by wireline logs interpretation. The studied interval subdivided into five main lithological cycles(A, B, C, D and E), with different thicknesses. Based on defined Gamma Ray cut offs, six electrofacies are distinguished in the Ha’py wells. The reservoir units are represented by repetitive sedimentary cycles (A2, B1, B2 and C) of one facies. These units are seen as three retrograding sand bar systems, the oldest one is represented by the A2 subcycle followed by the B1 subcycle and finally the B2 subcycle as the youngest dominant bar. These are followed by the lowermost part of the C cycle. These sand bars are possible to be mouth sand bars (Suter, 2006) that are activated by syndepositional tectonics and controlled by global eustatic sea level changes. The depositional environment of the studied area was supposed to be turbidite deep water or slump (Bailey et al., 1998), where the present study proved by detailed palentological studies that it is shallow marine water.
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Approach to the Differentiated Assessment of Prospects of Oil-and-Gas Content of Basement Formations of the Base of West Siberia
Authors V.L. Shuster, S.A. Punanova and A.V. SamoilovaSummaryMethodical approach to the differentiated assessment of prospects of oil-and-gas content of local structures by basement formations is based on the system analysis, allowing to carry out a multicriteria assessment of a choice of rational sequence of drilling of the prospecting areas. The Choice program is used. Each geological parameter was given a probabilistic assessment.
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Sedimentological Analysis of TP1-TP5 Layers in the South Tambey Field Study Area, West Siberian Basin
Authors A.A. Astakhova, E.A. Birkle and E.B. BondarevSummaryThe South Tambey field is a natural gas field located at the northern part of West Siberian Basin, on Yamal peninsula.
The main objective of this paper is to reconstruct depositional environment, and the main aim is creating integrated geological model of the field and showing sand bodies’- distribution within productive intervals.
TP1-TP5 are essentially composed of paralic sediments.
During the process of core description we managed to recognize 13 facies. This facies have formed 8 facies association, which have been defined from Open Marine, Paralic and Delta plain Facies associations. Sometimes different facies associations have a similar facial composition, the main difference between which is sediments’ regime.
This data has been analyzed in Techlog software with well logs’ and petrophysical data. Afterwards we recognized 8 electrofacies.
For generating facies’ map we used the following succession:
- Core data analysis, especially facies association, as a most important criterion.
- Well logs’ analysis, more specifically electrofacies data and correlation pattern with sand bodies’ distribution and sequence stratigraphy content.
Electrofacies helped us to reconstruct paleoenvironment in the intervals, where core material wasn’t presented. - Seismic attribute analysis.
Paleogeographic environments of TP1-TP5 have been confirmed.
Maps with the most potential reservoirs have been created.
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Comparison of Spectral Decomposition Result of High Density Seismic Data and Conventional Data Spectral Inversion
Authors Y.V. Protkova, M. Stollenwerk, A.A. Dorofeev and A.P. ZhukovSummaryRecently the expectation of geologists regarding the detail of geophysical data has resulted in more stringent standards of seismic data resolution. However when using conventional 3D seismic acquisition we have a low fold for shallow intervals at the target level and deterioration of the lateral seismic resolution respectively. In this case the solution to the problem is to apply high density seismic acquisition which lets us to increase the fold. In cases when oil companies have already completed the conventional seismic acquisition they try to save their money by applying broadband spectral inversion for this conventional data in order to increase the seismic resolution. In this paper the analysis of spectral decomposition results of the high density seismic data vs. the spectral ThinMAN inversion of conventional data have shown that for shallow intervals the sole application of spectral seismic inversion (ThinMAN) doesn’t let us to achieve the lateral resolution level like for high density seismic data. The spectral ThinMAN inversion in some cases allows us to enhance the seismic high frequencies but with a decrease of signal-to-noise ratio. That makes it difficult to interpret the seismic data in detail.
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Problems of Creation of Petrophysical Models When Integrating 3D Seismic Data
Authors G.V. Takkand and S.V. LyagushovSummaryThe problems of creation of petrophysical models when integrated interpreting 3D seismic and log data on a group of oil fields are considered. A novel approach based on deterministic and stochastic models is proposed. The approach provides an appropriate level of data reliability and enables us to perform integrated interpretation of 3D seismic and log data on a group of oil fields.
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Perspectives of Application 3D Seismic for Kimberlite Exploration
Authors L.V. Maksimkina, E.M. Goncharov and V.M. BoyarovSummaryProposed to use 3D seismic survey to search for kimberlites. In article presented the results of three-dimensional seismic survey on the local pipe-shaped object.
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Mapping Reservoir Fluid Using AVO Inversion, Spectral Decomposition and Facies Classification
Authors A.A. Babasafari and H. KhoshdelSummarySeismic reservoir characterization helps to find more information about rock physics in oil and gas explorations. One of the important properties in reservoirs is hydrocarbon saturation. Fluid content discrimination on seismic data is possible if it is feasible in well data and seismic data has adequate quality. In this study a gas carbonate reservoir is evaluated to map fluid distribution using integration of AVO inversion and seismic attributes. Feasibility study of fluid content discrimination was certified in well data by cross-plotting Acoustic Impedance vs. Vp/Vs logs. AVO modeling represents fluid effect as well. Results of simultaneous pre-stack inversion were used to predict water saturation cube which completely discriminate gas from water around GWC on surface attribute map. By subtracting of far stack from near stack data and applying iso-frequency component attribute over the volume the pay zone was discriminated from non-pay zone around GWC. This was confirmed again by unsupervised facies classification. This field has been already interpreted structurally and depth map of reservoir has been built. The contour level of GWC on depth map somewhere was not coincided in comparison with the observed gas content as demonstrated above. It illustrates that calculated reserve will be increased.(Close to 0.2 STCF)
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Clay Minerals in Pore Spaces, Improving or Reducing Reservoir Quality - A Siliciclastics Reservoir of Northeast Iran
More LessSummarySandstones, due to their interagranular pore space are important reservoir rocks in petroleum industry. Clay minerals are often one of the common substances in sandstone rocks, and in their presence they affect porosity and permeability effectively. Identification of the types of clay minerals in sandstones is therefore a key to understanding their reservoir quality. This study is focused on the origin, formation, diagenetic processes and eventually influence of clay minerals on reservoir quality in one of the clastic reservoirs in northeast of Iran by XRD, XRF and SEM analysis, together with more than 2000 petrographical thin sections examination. The results indicated that altered feldspars and albeit with low amount of hematite are the main sources for clay minerals. Clay minerals can destroy permeability in sandstones rocks but chlorites grain-coating in this quartz-rich sandstones can help to preserve porosity and permeability, they also impede quartz overgrowths on quartz grains in this sandstone reservoir. Time and temperature of chloride coating formation were deduced from chloride rim thickness around the quartz grains. On the other hand occurrence of illite in this reservoirs is mainly related to the reaction of K+ from feldspar with kaolinite, which has reduced the reservoir quality.
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Forecasting Permeability from Other Physical Properties Obtained by Laboratory Core Analysis of Several Western Siberian Fields
By B.N. EnikeevSummaryAuthors compare different relations to calculate logarithms permeability on a representative sample of core measurements of West Siberia reservoir rocks (1000 specimens).Equation involving logarithm of the saturation parameter prove to be the most accurate.
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Analysis of Special Investigations Weakly Core at Different Species Composition of Cement
Authors N.Y. Moskalenko and N.V. GilmanovaSummaryВ настоящий момент в рамках изучения слабоконсолидированного керна особое внимание уделяется лабораторным экспериментам по фильтрации флюидов, определению остаточной нефтенасыщенности и начальной водонасыщенности, петрофизическому и литологическому анализу. Целью данной работы является определения основных фильтрационных характеристик пласта при наличии в составе цемента рыхлых пород как каолинита, так и монтмориллонита
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Non-conventional Reservoirs Detection and Evaluation of Saturation Behavior by Neutron Methods Suite
Authors A.I. Lysenkov, V.A. Lysenkov, E.V. Sudnichnikova and L.K. BorisovaSummaryThe report describes the best practice of experimental, research and pilot-plant works, regarding the application of neutron methods suite SNGK+2NNKt to determine the saturation behaviour of complex reservoirs in open and cased holes. When drilling wells for polymer drilling fluids with low filtrate invasion, due to man-induced impacts a non-associated gas is evolved from oil into wellbore, it creates favorable conditions for determination of oil-and-gas-bearing formations.
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Development of LWD High-frequency Resistivity Tool
Authors M.N. Nikitenko, M.I. Epov, V.N. Glinskikh, K.V. Suhorukova and V.N. EreminSummaryPaper is devoted to the development of the new high-frequency electromagnetic while drilling tool. The complex of basic algorithms and programs for numerical modeling of logging data for geosteering and formation evaluation purpose is developed. Numerical modeling of electromagnetic signals in the horizontal oil and gas wells is performed. It is shown that the signals are sensitive to the resistivity of the oil-saturated part of the reservoir, and also to its roof and bottom. Results of test borehole measurements are given.
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High-frequency EM Log Data Interpretation in Realistic Reservoir Models
Authors M.I. Epov, K.V. Suhorukova, V.N. Glinskikh and M.N. NikitenkoSummarySome aspects of the numerical interpretation of VEMKZ (High-frequency electromagnetic logging) data are considered in paper. Algorithms have been created for the solution of forward and inverse problems in numerical interpretation of electromagnetic logs in realistic models of terrigenous reservoirs penetrated by vertical, inclined or horizontal wells. The signals modified by dielectrical permittivity were investigated. There also have been developed algorithms for numerical correction of borehole rugosities and probe eccentricity effects. Effective algorithms for fast two-dimensional modeling and inversion were developed. Joint two-dimensional inversion for relative amplitude and phase characteristics measured in electromagnetic logging allows to estimate electrical conductivity and dielectric permittivity. Algorithms for modeling in inclined and horizontal wells allow to investigate signal features when approaching and crossing boundaries. High-performance calculations on GPU allow to carry out numerical interpretation of data in real time.
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Casing Integrity Monitoring by the Combined Defects detector EMDS-3 in Oil-and-Gas Wells of Oman
SummaryThe combined tool EMDS-3 has been developed, comprising an electromagnetic defects detector of increased transmission distance, temperature gauge, gamma-ray unit, crystal quartz gauge and software, allowing to determine a wall thickness of the first, second and third strings from the borehole axis. There are results of the third string studies, which are of current concern in oil-and-gas fields of Oman. Using such data as temperature, pressure and rock gamma-activity in a well makes the data interpretation of defectoscopy more accurate and complete.
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Magnetic Pulse Defectoscopy-Wall Thickness Measuring of Wells
Authors G.I. Golovatskaya, A.P. Potapov, V.N. Danilenko and L.E. KnellerSummaryThe report describes a method of magnetic pulse detection to solve the problems of well integrity studies, points out characteristic properties of different modifications of MID-K, MID-K-GK, MID-K-GK-S, MIDS-K-100 systems, gives an interpretation method in view of corrections for different affecting factors.
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Electromagnetic Defectoscopy Application with Neutron Methods Suite to Evaluate Safety of Gas Wells
Authors A.I. Lysenkov, V.N. Danilenko, L.K. Borisova, E.V. Sudnichnikova and A.O. GabbasovaSummaryThe report gives an analysis of electromagnetic defectoscopy application together with neutron methods 2SNGK+2NNKt+SGK to cope with evaluation challenges of casing strings integrity and borehole annulus fillup and provide industrial safety expert review of operating gas wells.
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Possibilities of Formation Dipmeter Using AESB-73 Complex
Authors A.V. Gulimov, T.S. Mamleev, A.L. Ishbulatova and V.N. DanilenkoSummaryThe report describes scanning systems, used for dipmeter surveys, gives a brief description of data processing algorithms, obtained in dipmeter surveys by the system AESB-73 (ScanBK), provides calibration results of dipmeter surveys, carried out by AESB-73 (ScanBK) in a test well of OAO NPP VNIIGIS, shows the comparative results of dipmeter surveys, realized in two wells by ScanBK; these results are indicative of dipmeter surveys’ geological efficiency
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Interactions between High Power Fiber Laser and Rock in Shaley Formation During Drilling and Production Operation
Authors M. Bazargan, A. Koohian, H. Jalalyfar, M. Habibpour, M.P. Shahvar and A. MadaniSummaryThis paper is presenting the data on interactions between Fiber laser and shale. With this obvious goal that is dependent on improving the efficiency of laser power. The idea of selecting shale sample was because of variety of this rock type in Iranian oil and gas formations. In the experiment, a long pulsed laser beam was arranged to drill and propagate surfaces, in the opposite direction to the earth gravity, and it was used to drill hole from the top to the bottom of cylindrical Shale rock. The heat that been induced from the Fiber laser is absorbed in the direct surfaces in front and cause heat flux generation inside of rock texture. The specific heat transfer inside of shale sample can cause effects on many physical parameters such as porosity, permeability and resistivity. In the point of heat source, the temperature of the area can increase up to 500 – 1700o C, this temperature can show the influence of itself in fluid and solid materials that combine together in the porous medium. In this work we focused on effects of fiber laser heat generation on solid and fluid that been included in saturated shale.
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Experimental Investigation on Using Nano Additives in Designing of Smart Drilling Fluids - A Revolution in Drilling
Authors S. Hajighasemi, S. Rayatdoost, M. Soleymani and M. BakhtbidarSummaryFrom energy management viewpoint, optimum well drilling has been considered a serious demand to make maximum profit under minimum cost and highest safety for oil and gas companies. For reaching these goals, the drilling fluid as a most important part of the process has been targeted to be modified into a smart fluid using new additives. Since nano-technology has made a drastic revolution in characteristic of materials. in this study, it has been used to make an optimum drilling fluid including appropriate properties for dealing with diverse well problems like fluid loss and improvement of rheological properties. In addition to study the effectiveness of a Bio Polymer - Surfactant fluid blends, containing Nanoparticles as fluid loss additives have been presented to show their effectiveness in reducing the filtrate losses to the formation by forming a thin, non-erodible filter cake.
Laboratory experiments were carried out for the different combination of polymer and surfactant to find the optimum of fluid performance. The laboratory measurements included measuring mud weight, pH, viscosity, gel strength and standard API filter press.
Results show that sized silica nanoparticles can be used instead as a bridging agent. The nanoparticles play an important role in reducing the fluid loss.
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Theoretical Studies of Laser Cleaning Mechanism for Wellbore Mud Cake Removal
Authors M. Bakhtbidar, M. Bakhtbidar, G.H. Montazeri and R. HafiziSummaryThe present article focuses on the mud cake removal with laser radiation. Interactions of reservoir with drilling and completion fluids, mud cake and mud filtration, lead to formation permeability damages which result in reduction of production rate. Applications of laser technology have been widely developed in petroleum processes due to its significant positive effects. In this study, wellbore stimulation using laser radiation has been experimentally investigated. Various laser systems have been examined with different radiation times in order to find the optimum radiation time and intensity.
This laboratory study demonstrated that application of laser energy is capable of partially removing wellbore damage arising from the invasion of mud particles. The effectiveness of laser cleaning depends on the power of laser, the wavelength and the focal length. The extent of damage removal depends on the power of the laser, and on the coupling efficiency between the laser source and the materials in mud.
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Extraction of Heavy Oil at Thermal-wave Impact on the Producing Formation
Authors E.A. Marfin and A.A. AbdrashitovSummaryThe impact of elastic waves in the reservoir may increase the efficiency of oil extraction from the ground. Significant results have been achieved production of heavy oil when combined effects of elastic waves with the technology of in-situ combustion. The impact carried out using flow-through gas-dynamic pressure oscillations generators placed in the injection well at the end of the tubing. The report provides a description of field tests of technologies thermal-wave impact on the process of extraction of heavy oil and their results. Performance indicators are the effects of flow rates of wells, water cut yield, the specific energy costs. It is shown that due to the impact of elastic waves can be increased during the profitable development of heavy oil.
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Determination of Reservoir Parameters During Development of Well by Swabbing
Authors A.R. Adiev, A. Ramazanov and R.A. ValiullinSummaryDetermination of reservoir hydrodynamic properties (permeability and skin-factor) is important for the calculation of the well productivity index (PI) and the assessment of near-wellbore formation damage. The calculation of the reservoir properties is based on the pressure transient analysis (PTA) and can be performed during the well development after drilling (after workover) or during the pressure welltest. This technique of the reservoir properties assessment during the well development has already become a common practice. The whole operations, the same as production logging survey (or as PL), easily fit in the production technology planning of well development and allow the quantification of reservoir hydrodynamic properties. There are some features for the marginal production wells.
For the development of the low-margin wells, since natural lift is getting impossible, this is a common to use swabbing in Russia oil fields. Another technique to supply the artificial lift is the gas-lift method while either the air or inert gas are being injected in the annular space of the well to ensure the fluid flow by gas lift supplying. Conventional liquid jet pumps are also used on the practice. During the swabbing operations it’s usually not possible to perform pressure buildup test (PBU), thus the technology of the liquid-level buildup (LBU) in the wellbore is implemented, and in this case the change of the wellbore pressure is caused by the continuing inflow of liquid from the reservoir to the open wellhead.
It is known that for the analysis of the downhole pressure data (buildup test), when there is an impact of post-flow, the simultaneous determination of the formation permeability and skin-factor is not reliable. The main interfering factor is a strong influence of the continuing fluid inflow impact from the reservoir on the borehole pressure after well just has been shut-in (wellbore storage effect – WBS).
This work discusses the practical examples of the implementing the new technologies related to e-line instrument called as MGDI (module for hydrodynamic investigations), which easily can be combined with well development by swabbing. The main approach of the technology is the overlapping of internal annuli of the production tubing by MGDI tool conveyed by the cable. It is supposed to reduce the time of survey and this operation is expected to provide the reliable determination of reservoir pressure, permeability and skin-factor.
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The Relevance of the Structural Analysis in Geosteering Horizontal Wells at Russian Arctic Shelf
Authors O.N. Morozov, S.E. Dmitriev, D. B. Kislov, M.S. Sharov, A. Belyaev and Y.A. SelivanovSummaryExperience about drilling the first production well at Arctic shelf of Russia and emphasize the value of the comprehensive geosteering approach, including 3D geological model update to mitigate geological risks and perform safe and productive drilling.
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Modeling of Zero-offset Time Sections in TTI (Tilted Transverse Isotropy) Media by Pseudospectral Method
Authors A. Kostecki and K. ZulawinskiSummaryIn this paper we present a pseudospectral method of the modeling of zero-offset seismic time-sections in anizotropic media of tilted transverse isotropy (TTI) type, based on one-wave pseudoacoustic equation. This equation was derived from precise dispersion relation for 2D TTI media. Both cases for acquisitions of data along directions for “up-dip” and “down-dip” for two-dimensional anticlinal model TTI were considered. Obtained results were verified by depth migration MG(F-K) in wavenumber (K) – frequency (F) domain.
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Compute SVD of a Very Large Matrix in the Context of Geological Prospection
Authors S. Solovyev and S. TordeuxSummarySVD methods are nowadays at the heart of solving and analysing inverse problems in geophysic. Although the SVD analysis of large size problem is very expensive, there are different ways to overcome this limitation. The major of them are using HPC cluster parallelization algorithms, some limitation of input model and simplify the input model. In this paper, we present SVD low-rank approximation algorithm. It can be used to make SVD analysis of the linearized problems namely inversing seismic data in Born approximation. High performance of proposed algorithm is based on the fast decreasing singular values of Born matrix and on applying the adaptive cross approximation (ACA) technique. Performance of intermediate steps is improved by using BLAS and LAPACK components from Intel Math Kernel Library (Intel MKL) that is optimized for Intel architecture and parallelized via OpenMP. Validation tests showed that proposed Low-rank SVD approximates singular values and spaces spanned on the major singular vectors very well. Performance tests showed more than ten time performance on one-thread system. Algorithm has large opportunity for parallelization both on shared memory systems (using OMP parallelization) and on distributed ones (MPI parallelization)
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Some Questions of the Adapting the Order Filters to the Signal Form and Character of Noise
By V.I. ZnakSummaryThe objective of this paper is improvement of the quality of the vibroseismic research data under the condition of preservation of the form of a wave of a sounding signal. For this purpose, the weighted order statistics filters are offered. However, the given filters are nonlinear (an analytical estimation of their behavior is a complicated process), and the processing of periodic signals demands separate attention in this case (the filter response tends to zero when approaching the length of the filter to integer periods of a signal). At the same time, the filters belong to the nonlinear ones. The result of signal processing (the filter response) depends both on the filter parameters (including the dependence on a sequence of operations) and properties of a signal and the kind of noise. Thus, analysis of their behavior is rather complicated. In this paper, the technique of order filters adaptation invoking a method of statistical trials is offered, and the results of processing and restoration of the model of the noise swip signal are presented
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Seismic Tomography on Transmitted Waves for Researching of Kuznetsk Basin Coal Bed Structure
Authors B.A. Kanareykin, K.A. Dunaeva, O.M. Sagaidachnya and A.S. SalnikovSummarySeismic works in coаl mines are carried out with the purpose of disclosing of geological heterogeneity zones in lavas, it allows to decrease the expenses of coal production and to exclude the disastrous effects in view of unexpected detection of productive stratum breaking which was not disclose by preparatory excavation. Seismic tomography method of coal measure strata raying on lateral transmitted waves (guided, volume longitudinal and shear waves) allows studying the density structure of coal bed [patent 2455663 (RU)].
Works by defined method were carried out in some mines of Kuznetsk Basin in 2010 – 2013 periods. Obtained seismic tomography data confirm a priority of geodynamics for forming the coal bed internal structure. Discrete (close-meshed) nature and pronounced dependence of dislocated degree of coal measure strata and coal metamorphism are noted. Lamellar-mosaic spatial distribution of methane traps in coal beds is substantiated.
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Application of PSDM in Marine Seismic Data to Correct Pull-up Effect Caused by Highly Variation of Seafloor Morphology
SummaryIn order to confirm several leads in SE Matindok Area, 2D Offshore seismic survey (3060 km) in matindok Area has been carryout by Pertamina EP. In Processing stage, Pre Stack Time Migration (PSTM) has been applied to this seismic data sets. PSTM results show that in several seismic section “pull up effect” has affected the seismic images. The lateral velocity changing, caused by high differences in sea floor morphology, has caused the reflector below high morphology seafloor to be pull up similar to sea floor morphology. It can lead to false interpretation.
In order to solve this problem, Pre-Stack Depth Migration (PSDM) test line was conducted on Sequence 53. Velocity model was built based on reflector of top miocene carbonate interpretation. The PSDM result show that reflector of top miocene carbonate below high morphology sea floor in PSDM Section is more flat than PSTM Section. Besides that, fault structure images in this PSDM Section became more firmly and cleary than PSTM section, so we can have better understanding of the subsurface image geometry. Based on this test line results, Pertamina EP proposed 70 Lines (2634 km) to be re-processed using PSDM. Hopefully, PSDM results can reduce exploration risks in this area.
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Pre-stack 3D Land Seismic Data Merging in Cemara, Akasia Bagus and Tugu Areas of Northwest Java Basin, Indonesia
SummaryExtensive exploratory effort in Cemara, Akasia Bagus and Tugu areas has produced three different 3D land Survey till now. Processing and interpretation of these individual 3D Data sets have led to more exploration in the area. However, due to different acquisition and processing parameters, it was difficult to interpret subsurface image the overlap areas. The differences in Line orientation, bin size, charge size of sources, offset length, fold, amplitude, frequency contents, etc. have affected the quality of each seismic data sets.
In order to solve these problems, pre-stack 3D Seismic data merging was conducted. The main goal of Pre-Stack 3D Merging is to combine these original data sets into one data sets, processed as one project at the same time using same processing software. In the end, the comparison of fold coverage distribution, composite seismic sections and time slices, after and before merging, was made and shown significantly improvement in subsurface images. These merge data sets can help interpreter to get better understanding of geological process in these area
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Opportunities Use of Dynamics of the Refracted Waves
Authors A.N. Telegin and S.N. TabyrtsaSummarySeismic recordings of methods of the reflected and refracted waves contain information on features of a geological structure of the studied areas. This information is concluded in kinematic (arrival times) and dynamic (amplitudes) parameters of waves.
In a method of the reflected waves for determination of elastic properties of the studied geological environment in the course of processing of records widely are used not only kinematic, but also dynamic properties of waves.
In a method of the refracted waves kinematic processing is carried out generally. On productive kinematic cuts the provision of refracting borders and value of boundary speeds (without amplitudes) is, as a rule, represented. Dynamic properties of records are attracted only at a stage of correlation, definition of kinematics and the nature of waves.
The way of receiving the method of the refracted waves dynamic coal mines at which values of amplitudes of waves characterize difference of elastic properties in an entry point of the refracted wave in refracting layer or an exit from it is offered.
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Multi-Parameter FWI - An Illustration of the Hessian Operator Role for Mitigating Trade-off between Parameter Classes
Authors L. Métivier, R. Brossier, S. Operto and J. VirieuxSummaryFull Waveform Inversion is a powerful tool for quantitative estimation of subsurface parameters (P-wave, S-wave velocities, density, attenuation, anisotropy parameters). This methods has been applied successfully to 2D acoustic and elastic reconstructions, as well as to 3D acoustic reconstructions. Most of the applications of Full Waveform Inversion have been devoted to mono-parameter reconstructions of wave velocities. Multi-parameter Full Waveform Inversion aims at reconstructing simultaneously different class of subsurface parameters. This is a very challenging task: the similarity of the sensitivity of the data to different classes of parameters is the source of trade-off (or cross-talk) which renders the Full Waveform Inversion problem even more undetermined than in the mono-parameter context. This can related to the similarity of the diffraction patterns of different classes parameters for a given propagation regime. In order to overcome this difficulty, the role of the Hessian operator should be crucial. The off-diagonal blocks of this operator accounts for the trade-off between parameters. Incorporating the inverse Hessian operator within the Full Waveform Inversion scheme may help to alleviate this difficulty. On this basis, we provide in this study a very simple example for which we can compute exactly the Hessian operator we use to illustrate these issues.
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A Recipe for Practical Full Waveform Inversion in Anisotropic Media
Authors T. Alkhalifah and R. PlessixSummaryIn representing the most common (first-order influence, and gravity induced) acoustic anisotropy, transversely isotropic with a vertical symmetry direction (VTI) medium, with the P-wave normal moveout velocity, delta, and eta, we obtain a perturbation radiation pattern that has limited tradeoff between the parameters. Since delta is weakly resolvable from the kinematics of wave propagation, we can use it to play the role that density plays in improving the data fit for an imperfect physical model that ignores the elastic nature of the Earth. An FWI scheme that starts from diving waves would benefit from representing the acoustic VTI model with the P-wave horizontal velocity, eta, and epsilon. In this representation, the diving waves will help us first resolve the horizontal velocity, and then reflections, if the nonlinearity is properly handled, could help us resolve eta, while epsilon comes at the end to improve the amplitude fit (instead of the density). The model update wavelength for acoustic anisotropic FWI is very much similar to that experienced for the isotropic case.
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Full Waveform Inversion in Migration Based Travel-time Formulation
Authors G. Chavent, K. Gadylshin and V.A. TcheverdaSummaryThe common knowledge now is that standard least squares Full Waveform Inversion is unable to reconstruct macrovelocity for reasonable frequency band of input data but claims unpractically low time frequencies. There are a range of different approaches to overcome this weakness and among them Migration Based Travel Time reformulation of the cost function. Here we compare SVD for linear approximation of standard least squares Full Waveform Inversion with its Migration Based Travel Time reformulation. In order to do that we start with linearization of both nonlinear forward maps with subsequent computations of singular spectra (singular values and right/left singular vectors) for corresponding linear operators. The next step is to construct the two families of linear spans of right singular vectors corresponding to a set of fixed values of the condition number and to analyze their mutual disposition. Our computations demonstrate the reliable reconstruction of the smooth velocity component by full waveform inversion in migration based travel-time formulation.
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Analysis of Full Waveform Inversion Solutions Applied to Offset VSP Acquisition Design
Authors I. Silvestrov, D. Neklyudov, C. Kostov, M. Puckett and V. TcheverdaSummaryIn this work, we present a methodology that can be used to analyse resolution and stability of fullwaveform inversion solutions with application to offset vertical seismic profile(VSP) acquisition design. The method is based on singular value decomposition of the linearized forward map. We focus on the particular case of an offset VSP survey. Using a 2D isotropic model, we analyze efficiency of full-wave inversion for a particular example and compare scenarios with different types of sources and their offsets. We provide quantitative estimates for resolution and stability of inversion of different elastic parameters. The developed methodology may be used as a part of acquisition survey design during preparatory phase or as a quality control tool while performing inversion of registered data.
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The Multi-dimensional Complete Ensemble Empirical Mode Decomposition and Its Application in Seismic Denoising
Authors M.S. Parkan and H.R. SiahkoohiSummaryData decomposition has an essential role in seismic data processing and interpretation. So far variety of data decomposition methods have been developed especially based on time frequency analysis. Each of them has its own advantages and disadvantages. But the necessities for a powerful method which successfully overcome the decomposition of non-stationary and none-linear data steel exist.
In this paper we use the latest approach in BEMD introduced by Wu and Huang (2009). We updated this method by using the CEEMD and applied it for random noise attenuation from synthetic and real seismic data.
MCEEMD is a data decomposition approach which decomposes input data into tow-dimensional IMFs. Each IMF reveals separate features of the data. Multi-dimensional CEEMD can be applied on 2D seismic section or other higher-dimension data analysis. The method is based on a completely different approach from surface fitting methods and by passes major obstacles and difficulties in defining extremes. As an elementary application in seismic data processing the method was used for seismic data denoising. It performed well and significantly attenuated the random noise.
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Uniting Geologically-driven Earth Model Building and Seismic Depth Imaging
Authors K. Osypov, R. Bachrach, R. Pepper, D. Thanoon, S. Dasgupta and A. KlebleevaSummaryTraditionally, data-driven seismic tomography derives a velocity model used for migrating seismic data. This is followed by geologic interpretation of seismic images. This paper discusses how to close the loop and bring geological interpretation back to the Earth model building for seismic imaging.
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Efficient Numerical Simulation of Exploding Reflectors for 3D Heterogeneous Multiscale Media
Authors V. Cheverda, E. Landa and G. ReshetovaSummaryCommon Middle Point seismic sections and their successive time migration provide extremely important knowledge about the internal structure of the 3D heterogeneous geological media and are key elements for successive geological interpretation. Full scale numerical simulation, that is one which starts with single shot seismograms, provides a deep understanding how the features of the image are linked with its subsurface prototype. Unfortunately, this kind of simulations for realistic geological media and 3D seismic surveys needs huge computer resources, especially for simulation of seismic waves’ propagation through multiscale media like cavernous fractured reservoirs. In order to significantly reduce the query of computer resources we propose to model these 3D seismic cubes directly rather than shot-by-shot simulation with subsequent CMP stacking. In order to do that the well known “exploding reflectors principle” is modified for 3D heterogeneous multiscale media. Its parallel implementation allows modeling of realistic 3D Common Middle Point stacks with reasonable computational costs. Numerical results for simulation of Common Middle Points sections and their time migration are presented and discussed.
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Simulation of Seismic Wave Propagation in Models with Complex Free-surface Topography
Authors J. Diaz and V.V. LisitsaSummaryThis paper presents an algorithm for the numerical simulation of seismic wave propagation in models with complex free-surface topography. A free-surface is approximated accurate enough by a triangular mash after that the discontinuous Galerkin (DG) method is used to solve the elastic wave equation. However, the DG is more computationally intense than the staggered grid finite differences traditionally used for seismic modeling. The presented algorithm is based on the coupling of the two methods, so that the DG is applied only in a narrow near-surface part of the model, while the highly efficient standard staggered grid scheme is used elsewhere. This combination allows one account for the topography but keep the efficiency of the finite-difference simulation.
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Mitigation of the 3D Cross-line Acquisition Footprint Using Separated Wavefield Imaging of Dual-sensor Streamer Seismic Data
Authors M.T. Farouki, A. Long, R. Jones, Y.A. Chim, M. Tang, H. LeGleut, S. Lu, D. Whitmore and R. van BorselenSummaryLundin Malaysia BV completed the first-ever application of separated wavefield PSDM imaging to 3D dual-sensor streamer seismic data as a test to improve shallow geological interpretation. The methodology exploits the illumination corresponding to surface multiple energy, and thus exploits what has historically been treated by the seismic industry as unwanted noise. Whereas a strong cross-line acquisition footprint affected the very shallow 3D data using conventional processing and imaging, the new results yield spectacular continuous high resolution seismic images, even up to and including the water bottom. One implication of these results is that very wide-tow survey efficiency can be achieved without compromising shallow data quality if dual-sensor streamer acquisition and processing is used, even in very shallow water areas such as that discussed here. The imaging methodology can account for all degrees of lateral variability in the velocity model, full anisotropy can be accounted for, and angle gathers can be created to assist with velocity model building
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Simultaneous Long Offset (SLO) – A Case Study in Long Offset GeoStreamer Seismic Acquisition & Processing
Authors R.G. van Borselen, A.S. Long, E. von Abendorff, M. Purves and J. NorrisSummaryAn innovative 3D towed streamer project in offshore Gabon used a dual-vessel continuous long offset streamer configuration to acquire 0–12 km offsets with ten dual-sensor streamers. Streamer control for the 6 km streamers was robust and avoided operational complications or logistical penalties.
In simultaneous acquisition, data can be recorded with a temporal overlap between two (or more) simultaneously fired shots. Using random dithered time delays when firing the sources ensures that in certain domains coherency-based methods can be utilized to separate the simultaneously recorded data.
Simultaneous shooting maximized inline shot density for long record lengths, thus capturing unaliased deep target reflections from rugose base-salt and sub-salt horizons. Survey design benefited from prior 2D survey experiences with a variety of broadband source and streamer technologies, and the use of 2D streamers as long as 12 km.
3D illumination modelling further suggested that offsets as long as 16 km could be expected to yield useful base-salt and sub-salt reflections.
Wavefield separation processing yielded full receiver-side deghosting onboard, followed by an inversion-based separation of simultaneous shots onshore.
The ultra-long 12 km offsets combined with strong amplitudes of deghosted low frequencies have yielded encouraging sub-salt and pre-salt imaging.
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How to Get Wider Bandwidth in Land Seismic?
More LessSummaryTo Successfully Define Hydrocarbon Reservoirs And Characterize Reservoirs Of Different Types, Explorationists Need To Expand The Seismic Bandwidth From Current 3 Octaves (Say, 10–80 Hz) To 5–6 Octaves Toward Both Low And High Frequencies. To Acquire Such High-Resolution Seismic Data On Land, New Integrated Technologies Should Be Developed. These Technologies Includes Such Components As 1) Point-Source And Point-Receiver Acquisition, 2) Excitation And Recording A Wideband Signal, 3) High Spatial Sampling To Ensure Good Distribution Of Azimuths And Offsets In The Bins, 4) High Accuracy Of Source And Receiver Positioning.
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Selection of the Sampling Interval in Seismic Data Recording
Authors M.S. Denisov and A.V. CherepovskiySummaryThe sampling theorem states that a continuous analogue signal with limited (finite) spectrum can be uniquely recovered using signal’s discrete values taken at the frequency at least twice higher than the doubled upper frequency of the signal. At the same time the seismic records have limited length, and the amplitude spectrum of the seismic records is not finite. Consequently the process of discretization and recovery of the seismic signals inevitably cause amplitude distortions. The first type of distortions occurs in the process of trace recording, and the second type of distortions occurs at the data processing stage. Modern seismic is thought to ensure high resolution and reliable results of the investigation of the sedimentary cover. Seismic data are used to extract such characteristics of subsurface formations as lithology, fracturing, porosity, fluid saturation, etc. To successfully perform seismic inversion, errors related to signal discretization should be controlled and minimized. We offer a universal procedure of the selection of seismic data sampling interval.
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The Modern Technology of Seismic Prospecting with the Use of Reflection Method Applied to Oil and Gas Exploration
Authors S.B. Kireev, V.S. Litvinenko and A.N. TeleginSummaryPeculiarities of the modern seismic prospecting technology applying reflection method (OGT-3D) are considered.
The conducted seismic works should result in detailed data about elastic behavior of the geological section under study. The data are received with the use of kinematic and dynamic properties of the records. Elastic behavior is connected with the composition and conditions of sedimentation and rock formation that are essential for geological interpretation of seismic data such as prediction of the geological structure of the area under study and probable mineral deposits (oil, gas, coal etc.).
The seismic prospecting is optimally used for prospecting and exploration of oil and gas deposits. Technology parameters correlate with the geological structure complexity in the areas of sedimentation. The modern seismic prospecting makes it possible to predict the location of oil and gas deposits with high probability (on shore and in offshore areas), that is why seismic prospecting is included into essential works for all probable wells. This approach allows to reduce the number of non-productive wells and cut costs of exploration of oil and gas deposits.
The method has proved high geologic and economic efficiency in the field of oil and gas exploration. Thus the method turns into an industrial branch capable of solving fuel and energy tasks. Oil seismic prospecting costs account for 90–95% of total field geophysics expenses.
The paper gives examples of MOV-OGT seismic prospecting implementation in the prospective areas of Timano-Pechorskaya province
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Survey Design Considerations for Anisotropic Model Uncertainty Analysis
Authors L. Mulisheva, K. Osypov, N. Moldoveanu, O. Zdraveva, M. Woodward and Y. YouSummaryModern seismic acquisition geometries tending to cover all azimuths and increasingly growing offsets enabled a step change in illumination and quality of images, in particular in complex geological environments, as sub-salt. The paper discusses the impact of angle range in image gathers on uncertainty of anisotropy modeling. Various illumination scenarios were analyzed using tilted transverse isotropy (TTI) models over a field in the Gulf of Mexico.
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Problems of Seismic Acquisitions in the Conditions of the Eastern Ciscaucasia
Authors M.V. Gubarev and S.L. ProshlyakovSummaryThe main reasons, reducing the effectiveness of vibroseis survey for the study of oil objects in the Eastern Ciscaucasia are discussed. Appropriate for the complex fracture upper Cretaceous deposits
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Some Aspects of Seismic Data Preparation for Inversion
Authors M. Romanenko, S. Iliine and A. KharitonovSummaryThe report presents a number of approaches that have been developed through collaboration between processors and interpreters for seismic data preparation for the calculation of the inversion
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Seismoelectric Imaging Using Virtual Electrode Scanning
More LessSummarySeismoelectric scans can be used for direct mapping of the electrical and hydraulic properties of oil and gas reservoirs or acquifers. The scans involve virtual seismic electrodes which are produced by focusing acoustic energy at known positions in the subsurface and at known times. If the acoustic focus point coincides with a discontinuity in electrical and hydrological medium properties, then it generates an electric current density which leads to a difference of potential that can be observed with remote electrodes. Although seismoelectric phenomena are not new, subsurface monitoring using virtual seismic electrodes provide a huge improvement over existing methodology for two main reasons: the source of the seismoelectric conversion is localized in space, and the energy at the conversion point is maximum. The seismoelectric source behaves like a controlled electrode whose properties depend on the acoustic energy pumped into the ground and on the local medium properties. By changing the position of the focus point through appropiate time delays of the acoustic sources, we can scan the medium properties and produce a map of its properties. This map can either be used directly, or it can aid electrical tomography by increasing its resolution and robustness.
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Multicomponent Seismic Survey in Transition Zone of Pechora Bay with Node System Turtle-500
Authors Y.V. Roslov, A.A. Merezhko, V.V. Polovkov, D.A. Popov and E.G. ZhemchuzhnikovSummaryIn the period from June 18th to August 1st, 2013 “SEISMOSHELF” company performed 2D 4C(3C) multichannel seismic acquisition in the area of the Pechora Bay and its adjoining land.
The Russian-made seismic complex “Turtle-500” (“SEISMOSHELF” LLc, Saint-Petersburg) based on autonomous marine bottom modules (nodes) was used as a seismic recording system. The nodes are designed for recording of 4C seismic data at depths up to 500 m in seismic acquisition on basis of reflected and refracted waves; in landscape conditions that don’t allow the passage of a seismic vessel with a streamer, in shallow water, in places where it is difficult or impossible to use an ocean bottom cable, as well as on adjoining land and for seismic monitoring purposes.
The survey was carried out in full and high-quality multi-component seismic data has been obtained for the project area. Investigations done have confirmed that Russian innovation technology can be applied for transition zone and shallow water seismic projects.
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The Prospective Exploration Of Russian Arctic Continental Shelf
More LessSummaryAccording to the quantitative estimate of hydrocarbon bearing prospects as of 01.01.2009, Arctic waters have the greatest resource potential (87% of offshore potential resources). Made in recent years, integrated regional seismic survey from federal budget resources revealed a significant amount of oil and gas prospective structures. Today, the license areas issued by companies and their applications for licenses cover almost all prospective oil and gas offshore areas.
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Tectonics, Sedimentation And Hydrocarbon Prospectivity Of The South Barents Sea Region
Authors V.N. Koloskov, D. Nadezhkin, O. V. Pinous, O.V. Chernova, A. Aseev, L.M. Surguchev, E. Bykova and A.S. RabeySummaryAn integrated study has been conducted for the area of the southern part of Barents Sea. The detailed comparison of the stratigraphic patterns of the Norwegian and Russian parts of the shelf has been performed for the entire interval from Carboniferous through Jurassic. The ages of the key tectonic events, have been verified. Investigation of core data with seismic facies analysis enabled to improve determinations of determinations depositional environments and paleogeographic reconstructions. The best reservoir quality rocks are expected to be present within the Triassic shallow marine to fluvial sediments of Snadd, Kobbe andHavert formations, as well as JurassicStоandNordmela. Among the most interesting interval of the Paleozoic sections there are siliceous spiculites of Roye formation, which may contain good reservoirs in zones above Sakmarian-Artinskian bioherms. The most obvious structural traps have been developed above the salt pillows, and additional prospects may be present at the flank zones of salt diapirs
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Sedimentary Environments in Cenozoic Basins of the Okhotsk-Bering Sea Region and Specialities of Oil and Gas Source Rock
Authors B.V. Senin, E.A. Lavrenova and M.E. EreskoSummaryPaleogeographic reconstructions of sedimentary basins of the Bering Sea and the Sea of Okhotsk in Paleoсene - Eocene, Oligocene-Miocene, and Pleiocene-Quaternary time have been performed in the framework of the presented work. It is found that frequent alternation of different sedimentary environments varying from continental erosion and denudation hilly plains to the relatively deep marine outer shelf took place within the studied shelves during Cenozoic. Possible occurrence areas of oil and gas source rocks of variant quality are predicted in Paleogene and Neogene sediments offshore and on contiguous land on the base of the reconstructions and results of organic matter studies in wells. The obtained results form a part of the required input data set used for modeling of generation-accumulation systems of the Bering Sea and the Sea of Okhotsk.
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Multicomponent Marine Seismic Survey In The Arctic Shelf On The Base Geospace Technology
Authors S.A. Nechkhaev, G.S. Kazanin, G.I. Ivanov, A.V. Zimovsky and V.A. ShedrovSummaryIn July-September2013 on the Arctic shelf within 2 regional projects of “MAGE” seismic workperformed 2D-4C totaling 400 linear meters. Km using subsea system cordless battery seismic waves typeOBX Geospace produced by OYO Geospace Ind.(USA). In regional marine seismic studies use OBX Geospace Arctic shelf technology has been developed to record the seismic signal in the depth range 0 +1 / −50 m quality seismic data to a greater extent dependent on hydrological and weather conditions in the study area , and was not uniform due to the geological conditions volatile medium. As work and promotion of Baydaradskoy lips to North Yamalledge , an increase in the ratio of C H horizontal geophones . Quality Control H and Z components was conducted programs ProMAX R5000 and SeisWin QC. Given the heterogeneous nature of NSS in the project area, an analysis of the data obtained by X, Y components that showed the possibility of registering the PS waves with low noise level in the shallow waters of the Arctic shelf. Taking into account the large meridional extent of the work area, it was found similarities adjacent waters of the western Priyamalya in nature geological structure of the upper part of the section where universally developed alopecia permafrost.
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Palaeogeography of the North-Eastern Black Sea and the Western Caucasus in Mesozoic and Cenozoic
Authors B.V. Senin, M.V. Kruglyakova, E.A. Lavrenova, M.I. Leonchik and A.A. GorbunovSummaryReconstructions of paleo-sedimentary environments in the North-Eastern Black Sea were intended to achieve three main objectives: to forecast the geographical range and depositional environments of potential oil/gas source rocks, reservoirs, and seals; to study sedimentation environments in the areas of fields - analogs for the purpose of quantitative assessment of prospective targets’ potential in the Black Sea Basin, to prepare a necessary part of input data for three-dimensional basin modeling and prediction of oil and gas occurrence offshore.
The research results indicate that, reasoning from sedimentation environments, Middle Jurassic, Lower and Upper Cretaceous, and Maikopian clayish deposits accumulated in the deep-water environments of the outer shelf and continental slopes of age-appropriate paleobasins, may have oil and gas source rock properties.
Reservoirs may be represented by Upper Jurassic shelf carbonate deposits, Lower Cretaceous clayish carbonate deposits, Upper Cretaceous carbonate deposits, Maikopian and Middle-Upper Miocene coastal or deep-water ( turbidite ) terrigenous deposits.
Terrigenous and terrigenous-carbonate deposits of different horizons in the sedimentary section may serve as cap rocks.
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How to Benefit from Monte Carlo Simulations in Petroleum Systems Modelling to Estimate the Amount of Erosion?
Authors K.J. Zieba, M.C. Daszinnies, S.J. Lippard and A. LotheSummaryErosion estimates are crucial in reconstructing the burial history of the Barents Sea basins, where the lack of major success in oil exploration is attributed to the Cenozoic uplift and erosion. The magnitude, lateral and temporal distribution of erosion estimated by methods like AFTA, VR or by deterministic basin modelling often leads to very different results and/or does not account for uncertainties inherent to input data. Here, this challenge was approached by using Monte Carlo - secondary migration basin modelling simulations, where input data (early and late Cenozoic erosion episodes and palaeo-thermal gradients) were described by probability distributions, and model results were evaluated statistically.
Two overpressure scenarios were also considered in the modelling. Constrained a posteriori erosion parameter distributions showed a relatively narrow range of possible solutions. It was shown that the early Cenozoic erosion episode was more severe than the late Cenozoic event. A posteriori distribution mean values were much lower than a priori mean values (which represent initial beliefs) suggesting lower amount of erosion than expected. Overpressure modelling does not affect the minimum and the maximum erosion amount estimates to a high degree. Slight differences might be however observed for the early Cenozoic erosion event.
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Geological and Geophysical Deep Structure Researches of Northern Eurasia in the Zone-block Model of the Earth’s Crust
Authors A.S. Egorov and V.D. GulinSummaryInvestigations of the deep crustal structure of the continents and their passive margins along the supporting geophysical profiles, within the framework of small-scale geological mapping and regional studies of large economic geologic regions, based on the broad base of regional geophysical surveys, opening way to development schemes, maps and sections of the new type.
Solution of the incompatibility problem of heterogeneous geophysical information and improve the reliability of interpretation constructs seen in the postulation of several key positions: a) deep crustal section are documents tectonic content; b) the deep cuts seen as components of a three-dimensional model of the region geotectonic research; c) the interpretation of the geophysical data is within the “zone-block geophysical models of the Earth’s crust”, the main elements of which are the blocks (paleoplity) with the ancient seismically layered continental crust, manifesting as the stationary regions calculated seismic, geoelectric, gravimetric, magnetometric, geothermal parameters and sharing their interblock sutures structure (tension, compression and fault) - gradient zones of geophysical fields.
In this methodology, performed mapping the deep structure of consolidated basement and platform cover of the continental territory of Russia, an extensive system of deep sections of the Earth’s crust along the profile of the regional DSS-ECWM, DRS-CDP, MTZ.
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Gas Potential of the Kuff fm in Western Kurna-2 Field, Iraq
By K.A. TaovSummaryПроведена работа по синтезу имеющегося материала по геологии региона из отечественных и зарубежных источников.
Построены модель погружения и оценены темпы прогибания бассейна осадконакопления, что позволило реконструировать обстановку, что соответствует росту карбонатных (рифовых) построек, их литологические и коллекторские свойства.
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Some Results of Tectonic Evolution Study of Northern West Siberia Fields
Authors A. Kurkin and I. GrigorevaSummaryIn the north of West Siberian basin, fields have relatively complex fault pattern. Most hydrocarbon pools of the field are tectonic traps. This makes understanding tectonic evolution of the area very important. Methodology used in this study is based on restoration modeling of seismic sections (paleoreconstructions, accounting for geomechanical properties), structural analysis of sections and maps. As a result, a geologically consistent structural and tectonic model was created and interpretation of faults and horizons was improved. Timing of faults activity and anticline formation usually is not taken into account in oil and gas companies working in this region, but it is very important. It should be used in risk estimations and in basin and reservoir modeling, as timing of the fault activity determined in this work helps to explain dry wells in some intervals. Some important conclusions for regional geology can be made. Four stages of tectonic activity were defined: oblique extension with creation of en-echelon normal faults in Middle Jurassic, growth of anticline and creation of normal faults in Early Neocomian, Middle Albian-Cenomanian and Post-Cenomanian. Strike-slip movements with elements of extension and compression explains growth of normal faults in the same time with growth of the anticline.
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Cenozoic Geologic Processes and Their Role in Forming of Petroleum System at Demyanskiy Megaarch
By D.A. SidorovSummaryIn Cenozoic time changes of vertical and lateral direction of tectonic processes took place within Demyanskiy megaarch and adjoining depressions. Structural trends orientation changed from northwestern to north-eastern and regional down movements gave way to uplifting and partial erosion of previously accumulated sediments. Structural changes of main Jurassic and cretaceous oil-and-gas bearing horizons in Cenozoic time affected hydrocarbons lateral migration pathways and source rocks maturity distribution.
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Modeling the HC Potential Formation in the Southern Part of the Lena-Tunguska Oil and Gas Province
Authors O.I. Merkulov, P.N. Sobolev, E.V. Postnova and I.A. ZinchenkoSummaryThe primary objective of geological exploration in the south of Eastern Siberia is improvement the reliability of resource potential assessment in the southern part of the Lena-Tunguska petroleum province and justification of the oil-and-gas accumulation zones inside. Formation of the current hydrocarbon saturation of the section occurs mainly due to the Riphean source strata with subsidiary role of the Vendian and the Cambrian. The three main stages of hydrocarbon emigration and migration are identified in the southern part of the Lena-Tunguska oil-and-gas province: the Vendian-Early Palaeozoic, the Middle Palaeozoic and the Late Palaeozoic-Mesozoic. Hydrocarbons generated before the formation of the Vendian-Cambrian regional seals were most likely scattered in sedimentary deposits and had no impact on the modern oil-and-gas potential. Main regional oil-and-gas prospects are related to the three oil-and-gas bearing complexes - the Riphean, the Vendian and the Vendian-Lower Cambrian. The hydrocarbon accumulation formation in the latter two is caused predominantly by vertical migration from the Riphean generating centers. The major HC field formation mechanism was the secondary migration of gaseous hydrocarbons and the rearrangement of pre-existing oil fields into the oil-and-gas, and the oil-gascondensate deposits
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Searching for New Prospective Objects and Revising Tectonic Structure of Pre-Paleozoic Complex of Bashkortostan Republic
Authors G.B. Salakhova, R.A. Zimenkov, V.V. Kiselev and R.H. MasagutovSummaryTerritory of platform Bashkiria, located on the east end of the Russian platform, in its joint area with Ural orogen, is one of the oldest oil-producing regions of Volga-Ural oil and gas bearing province.
Based on results of CMP-2D seismic exploration works for 2011–2013 years more than 5 thousand linear km. of lines were acquired, 117 wells were prospected, which uncovered the Riphean sediments within the territory of Bashkortostan Republic. This allowed us to revise the geological model, fault-block tectonics and to allocate prospective objects, where it is recommended to carry out detailed seismic works for the purpose of the given structures composition revision with further recommendation for drilling exploration wells.
In western and north-western parts of Bashkortostan Republic territory from the south to the north – Ivanovsky high is worth noticing.
In the central part of Bashkortostan Republic territory Birsky high and Kushkul structure of inversion type are of the main interest. In eastern and north-eastern parts of the platform territory the South-Tavtimanovskaya closure is of a prospecting interest along the Riphean sediments, being the main element of Arov-Kultubinsk anticline.In the south-east of the territory Arlarovsky and Kulguninsky highs are worth special noticing.
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Composition and Sedimentation Pecularities of the Upper Jurassic-Lower Cretaceous Black Shale Bazhenov Formation in the Central Part of West Siberia
Authors V.G. Eder, A.G. Zamirailova, Y.N. Zanin, P.A. Yan and E.M. KhabarovSummaryA detailed study of the lithological sections of the Upper Jurassic-Lower Cretaceous black shale Bazhenov Formation was made in the central part of the West Siberian geosyneclise (Salymskiy and surrounding regions). It is observed the following upward sequence of rocks in most of the studied sections: siliceousclayey rocks – radiolarian cherts - microcrystalline cherts – mixtites (calcite, quartz, clay, organic matter about 15–20 % each). Gradual increase of clastic material in the rocks is fixed, and different stages (from early to late) of sea level high stand are established. The most favorable period for the accumulation of organic matter (OM) was the late stage of high sea level stand (LHST1). In the present study, in Western Siberia on the border of the Jurassic and Cretaceous stages it is observed: a. abnormally high (the maximum for the section of Formation) uranium content; b. change of biogenic siliceous sedimentation to the siliceous-carbonate one. This change in sedimentation during this period also was recorded in the Tethyan belt, and is associated with the global restructuring of the geochemical conditions in the oceanic waters of the northern hemisphere in the J/K boundary.
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The Bazhenov Formation Geological Models Creation on the Basis of Complex Core and Seismic Exploration Data
Authors V.D. Nemova and I.V. PanchenkoSummaryIn the report is shown the attraction of detailed litological, petrophisical and geochemical researches of a representative core data can be used for a problem definition at interpretation of GIS and 3D seismic and promote to increase quality of geological model of the Bazhenov formation. Relevance of approach is defined by that many methods of work with traditional reservoirs weren’t applicable to the Bazhenov reservoirs. Researches of a large number of fields with the proved efficiency of deposits of the Bazhenov formation located within various tectonic elements of Western Siberia, carried out by a uniform technique, allow to study and compare features of such fields, to prove similarity or distinctions like their oil-bearing capacity, a structure of reservoirs and the dominating factors defining degree of efficiency of this strata.
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The Localization of the Productive Areas of the Bazhenov Formation in Western Siberia (Methodology, Innovative Technologies)
Authors V.V. Kharakhinov, S.I. Shlenkin, V.A. Zereninov, M.V. Berin and A.V. OljyninSummaryUsing new technology for creating fractured reservoir geological models of the Bazhenov Formation, which is based on a comprehensive interpretation of 3D seismic data on the reflected and scattered waves and well information.
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Prediction of Oil-Productivity of Fractured Clay Reservoirs by Seismic Data
Authors M.L. Afanasiev and E.A. KopilevichSummaryThe study of fractured reservoirs clay using seismic data is a complex task. Modern applications (Multi-Wave Seismic, Tectonophysical Modeling, PRONY-Filtering) do not predict the oil-productivity directly, but simply engaged in mapping of fracture zones.
In the fractured clay reservoirs a large heterogeneity of clay deposits means the formation of fractured zones. These zones represent potential reservoirs of oil with increased productivity. To estimate it authors proposed to use the Capacitive Differentiation Factor (CDF). CDF is the ratio of the total productive capacity of fractured reservoirs clay to the total capacity of reservoirs, which have the capacity in two and more times higher than the average capacity of the target interval.
In the innovative technology of spectral-velocity prediction (SVP-technology) the method of prediction of oil-productivity of fracture clay reservoirs is implemented. The Spectral-Time Attributes are well correlated with the CDF and the CDF - with the oil-productivity.
The described method was tested for studying the Bazhen deposits in Western Siberia. The described method for predicting of fracture oil-productivity clay collectors on the basis of Spectral-Time Analysis of the seismic record is innovative and has high confirmability of subsequent drilling.
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Petrophysical Aspects of Bazgen Deposites Formation Evaluation
Authors B.N. Enikeev, V.V. Kolesov, M.L. Lebedeva, O.A. Smirnov and O.M. SusaninaSummaryAuthors compare bazhen sediments to gas shale using empirical data. They illustrate how specific are bazhen sediments and focus on the ways of using those specific features to formation evaluation of bazhen deposits. Proposed new algorithms and explained several practical cases.
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Overview of Current Shale Gas Exploration and Production Activities Worldwide
By S.S.H. KazmiSummaryShale gas reservoirs are fine grained organic rich formations which act as source as well as reservoir rocks. Typically, shale matrix permeability is very low and requires additional stimulation treatments for economic production.
This work focuses on the characteristics of shale gas reservoirs and production activities worldwide with a special focus on Germany. A brief overview of the major shale gas basins in different countries of the world is presented along with their major reservoir properties.
The geology of the shale gas reservoirs is discussed in detail. Also, emphasizes has been laid on the study of the important reservoir properties of shale gas reservoirs and different methods used both in field and laboratory to measure these reservoir properties.
This work provides an insight into the Hydraulic fracturing, horizontal drilling and the equipments used for production from shale gas reservoirs.
A comparison of the different rock properties and production profiles from different shale gas reservoirs of the world is done and a table is prepared for economic production of shale gas reservoirs.
Finally, the simulation of one of the Barnett shale gas well is carried out and production profile of the well is analyzed and the results are discussed.
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Simulation of Oil Generation from Oil Shale Resources
Authors A. Rasouli, A. Shekarifard, F. Jalali Farahani and M. KökSummaryOil shale is a type of unconventional hydrocarbon resources with a capability of oil production by practical thermal process called retorting. Mechanism and kinetic study of reactions occur in this process can provide the possibility of theoretical reconstruction of it and furthermore, the simulation of retorting process. Parallel, irreversible, first order reactions are the well-known type which used to modeling the reactions. Mentioned model are simulated with Simulink® (MathWorks® Inc.). By considering the appropriate values and conditions, the consumption of reactants and generation of products are studied with time and temperature. Reducing the temperature of reactions by reducing the heating rate is clearly observed in the results of simulation. Also, the effect of intermediates is apperceived well. Eventually, the study of the in-situ retorting as a simple process is shown the modus of the consumption of reactants with time and also, the importance of intermediates more than ever.
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Characterization and Hydrocarbon Potential Evaluation of a Shale Gas Reservoir Using Cuttings (SW Algeria)
Authors M. de Block, A. Hofmann, C. Rigollet, E. Portier, R. Haverkort, B. Bruins Slot and S. BurnsSummaryMethods for determining properties of shales from cuttings samples are beneficial as they provide a fast and cost-efficient way for evaluating potential shale reservoirs for which often core sample data and modern wireline logs are missing. A case study is performed on 80 cuttings samples from the radioactive Silurian shales of a Palaeozoic basin in SW Algeria. In this study geochemical (Rock-Eval pyrolysis and LECO carbon analysis), mineralogical (QEMSCAN analysis), structural (CT scanning) and geomechanical (nanoindentation) analyses are performed on cuttings samples to characterize the heterogeneity of the shales and predict shale gas sweet spots. Using these innovative analysis methods reliable values for the properties of the radioactive Silurian shales are obtained. By integrating TOC content values and QEMSCAN data with wireline logs, clear vertical trends/cycles are identified and the strong vertical and lateral heterogeneity of the shales is demonstrated. Using CT scanning different fractural networks are observed and Young’s modulus values obtained from nanoindentation measurements are in the range expected for shales (± 33 GPa) and are appropriate for shale gas production. The shale gas opportunity is confirmed for the radioactive Silurian shales and sweet spots are indicated by high TOC contents and favorable mineralogical compositions and geomechanical properties.
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Forecast of Unconventional Reservoir in the Clay-carbonate Sediments of the Lower Triassic of the East Manych Trough
Authors B.A. Solovyev and S.P. LevshunovaSummaryFor the first time the pecularities of shales (argillites and argillaceous limestones) of the Lower Triassic Formation of the East-Manych depression (the North Caucasus) as non-traditional reservoirs for a shale gas resources are discussed. The comparison (geochemical and petrophysical information) with the Lower Cretaceous Pearsall Formation ( South Texas) is completed. The Pearsall formation is in the dry gas window of hydrocarbon generation (mean random vitrinite reflectance values, Ro=1.2–2.2%). For organic matter of the Lower Triassic Formation Ro ranges from 1.16 to 1.75%. Conventional petrophisical measurement techniques of the Pearsall core samples indicates that porosity ranges from 1.6–6.7 to 10%, similar to that for shales of the Lower Triassic Formation − 5%. Ordinary permeability measurements range from 0,003 to 0,062 md in the cores of the Pearsall Formation and 0.3 md in shales of the Lower Triassic Formation. There discovered closed and opened fractures in this formation to 5000m, but they are absent in the Formation Pearsall. Using our three inventions we found the genesis of these fractures.
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Shale Oil and Mineless Exploration Technology of Bituminous Shales
By V.N. IlyasovSummaryMineless exploration technology is developed for extraction of hard-to-reach mineral resources presented by thin productive stratums within the fields of any complexity factor.
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Unconventional Hydrocarbon Complexes of the Eastern Azerbaijan
Authors M.A. Afandiyeva and V.V. KorobanovSummarySedimentary complex within East Azerbaijan is composed of a series of stratigraphic complexes that may contain non-conventional hydrocarbons. These complexes include the Eocene rocks (Kounian formation), Oligocene-Lower Miocene (Maikop series), Middle-Upper Miocene (diatomaceous suite).
Study area is related to geodynamic active eastern segment of the Greater Caucasus of Alpine-Himalayan fold orogenic belt at the junction of the North and the South Caucasian microplates.
Lithologically the most part of these deposits are mainly composed of thickness of dark-grey shale or hard clay with rare stratified sands and sandstones.
The conducted studies allowed the authors for the first time to take a fresh look at the sedimentary complex of Paleocene-Miocene deposits within Eastern Azerbaijan. Rocks of Paleogene-Miocene age in Kounian, Maikop and diatomaceous suites within the study area with available geological-geochemical factors allow us to consider this complex as a prospective one in terms of accumulation and formation of “shale” HC fields.
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Bulk Geochemical Characterisation of the Source Rocks for Shale Gas in Poland
More LessSummaryThis paper presents the general geochemical characteristics of Silurian shale with the aim to constrain its shale gas potential in Poland.
Estimating the reserves in shale type reservoirs required more interdisciplinary treatment than the works devoted to this subject in conventional reservoirs. In evaluation presence of water and oil in the pore space must be taken into account consideration. The next problem is possibility of existence of pore space in organic matter. Not only free gas existed in such type of pore space but also absorbed one, so in the calculations a ratio absorbed to free gas must be included.
The most important in shale gas investigations are geochemical works, with the usage of rocks samples as well as gas samples, from degasation of cores and from reservoirs. These type of investigations makes it possible to execute a quantitative evaluation GIP (Gas in Place), and the same calculation of reserves of gas. The first of all should to determine the content of organic matter and thermal maturity level, which is crucial for selecting the sweet spot for shale gas. All these estimations could be made on the basis of archival data as well as recent ones from newly drilled bores.
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Innovative EOR Screening Methodology to Support Field Development Decisions
Authors M.F. Leon Carrera, E. Escobar Alvarez, J. Guitian and T. NnangSummaryNowadays, Enhanced Oil Recovery (EOR) processes have become crucial for Energy Companies to reach the desired field performance. However, the selection of the appropriate EOR process or tailor made sequence of EOR processes is not a straightforward decision. The screening and evaluation of EOR technologies requires the expertise in several discipline domains: reservoir characterization, numerical simulation, surface facilities engineering and environmental impact studies. The adequate evaluation of EOR process will permit Energy Companies to make field development plan decisions that are technically sound and to move forward to pilot tests and commercial scale.
In Repsol Technology Centre (CTR), we have developed a methodology for the screening of EOR processes. The methodology considers the reservoir characteristics and compares the target field with analogue fields. Besides, it integrates the recovery factor of the available technologies as well as their associated cost including environmental impact. This unique workflow consists of four steps detailed as follow: 1)Identification of analogue fields, 2)Quick Look EOR Screening, 3)Spatial EOR Screening and 4) Technology ranking.
The EOR screening methodology developed by CTR has been successfully implemented and covers all EOR technologies for conventional and unconventional fields. The methodology can integrate the associated geological uncertainty in the application of selected EOR technologies.
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Criterion Analysis to Justify the Wells Selection for EOR
Authors I.V. Evdokimov, S.B. Denisov and I.D. BreslavichSummaryThe report shows the methods of criterion analysis of geological and production data. These methods justify the reasons of the high water cut, wells selection for the forced production, lateral holes drilling, increase well productivity, optimize the system to maintain reservoir pressure. Particular attention is paid to ways to create an array of wells that require evaluation of the causes of deviation from the targets activities. The data for evaluation of technical efficiency activities are obtained by performing calculations of each variant of oil, fluid production, and the energetic state of wells in the space of 3D. Interference effects of wells and filtration flow changes both increase or decrease production of individual wells. Therefore the estimate of the effect of measures performed only in wells which held EOR gives overestimate. The methods of performance evaluation systems to maintain reservoir pressure are discussed. The report shows methods of technological and economic evaluation of different EOR methods. Analysis and methods are presented in this report were used to enhance production of mature oil fields in Russia and abroad
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Acid Trending Compositions on the Basis Of Inverse Emulsions for Intensification of Oil Production
Authors A.R. Mavliev and M.A. AzamatovSummaryToday effectiveness of acid treatments in polymineral reservoirs in Western Siberia is low despite of the great experience and a long history of use. The analysis of acid treatments shows us that the main categories of factors are: lithological, geological, technical and technological. On the base of existing technologies analysis we can make the conclusion of the necessity to integrate the acid treatment with injection of reverse water-oil emulsions. More over the emulsion must be injected before acid composition in order to temporary blocking of high permeability washed intervals and subsequent acid treatment of low-permeable interlayers.
During the laboratory experiments the dependences of water-oil emulsions properties in accordance with concentration of components have been revealed. This allows us to product the highly effective acid trending compositions. The main result of laboratory experiments became the possibility of emulsions adhesive properties increase in relation to the formation and metal due to the increase of the content of the aqueous phase and dispersion. It gives higher values of residual resistance factor after filtering emulsion composition through the formation and improved protection of downhole equipment from corrosion. After three complex treatments of wells in the Branch of «Gazpromneft-Muravlenko» OJSC « Gazpromneft-Noyabrskneftegaz» the efficiency of the developed acid composition and the technology of its injection with an emulsion was confirmed. Due to proposed solutions the increase of effectiveness of bottom-hole formation zones acid treatments is up to 40%.
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Optimization of Drilling and Production Operations by Application of Laser Technology on Iranian Fields
Authors M. Soleymani, M. Bakhtbidar, S. Rayatdoost and A. GhajariSummaryPetroleum industry welcomes new drilling technologies that not only decrease oil and gas wells drilling costs but also increase rate of penetration. Entry of new advanced technologies to the oil and gas industry in the countries having hydrocarbon resources led them to improve their position in the world, likewise moving toward greater profitability. Abandonment of traditional methods and good infrastructure for research and development of new technologies could be the key to advancing this industry as well as reducing the related heavy costs. According to the statistics, in the drilling of a well 48% of time spent on drilling from surface to the reservoir, 27% spent for bit replace and casing running, and 25% spent for logging while drilling. The methods which could be reduce the time of drilling, and bit replacing time would be very effective in reducing the costs. Our experiments demonstrated that the laser drilling method is the best way for saving in time and cost in oil and gas wells drilling and completion.
Moreover, results shows we can imaging many applications of laser beam in petroleum industry such as, laser perforation, mud cake removal, and create the windows in order to production of multilateral layers.
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