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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 - 50 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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