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7th EAGE Saint Petersburg International Conference and Exhibition
- Conference date: 11 Apr 2016 - 14 Apr 2016
- Location: Saint Petersburg, Russia
- ISBN: 978-94-6282-179-8
- Published: 11 April 2016
1 - 50 of 198 results
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Regional and Local Forecasts Oil-Bearing in Bazheno-Abalak Complex of Western Siberia
By M.Y. ZubkovProposed list of criteria to assess the prospects of regional oil-bearing Bazheno-Abalak complex and original method of local forecasting based on aggregation of seismic data and tectonophysical modeling
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Collectors Tectonic-Hydrothermal Origin in the Pre-Jurassic Complex of West Siberia and Methods of its Forecasting
By M.Y. ZubkovSubstantiates the tectonic-hydrothermal formation mechanism of secondary collectors in the roof of the pre-Jurassic complex of West Siberian oil and gas basin, a method of searching on the basis of seismic data, proved that served as the source of hydrocarbons Jurassic deposits.
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The SiO2 Occurrence and Origin in Shale Reservoir, a Case Study from the Yanchang Formation, Ordos Basin
By L.G.H liuThis study employs samples from the Yanchang Formation of Ordos Basin, probing the SiO2 occurrence and origin in shale reservoir in order to figure out the effect of SiO2 on physical shale properties.In order to research the SiO2 occurrence and origin in shale reservoir a series of integrated and repeatable methods has been used including X-ray diffraction of bulk and clay minerals, cathode luminescence analysis, Ar-ion polishing, focused ion beam scanning electron microscopy (FIB-SEM) and energy dispersive spectrometry. three point-views were drawn about SiO2 occurrence and its effect on rock property.
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A New Method for Semi-Quantitative Analysis of Amorphous SiO2 in Terrestrial Shale a Case Study About Yanchang Formation
By L.G.H liuYanchang Formation shale of Ordos basin contains a certain amount of amorphous SiO2, which proved by SEM observation and X-ray diffraction analysis of bulk rock. The three methods proposed by now to calculate the quantity of amorphous SiO2 have their own flaws. The disadvantages of chemical denudation are experimental period and unconvinced accuracy because of dissolving other minerals. Quantitative analysis of amorphous silica by X-ray diffraction possesses high personal error on the integrated intensity of dome-shaped scattering curve in XRD spectrum of amorphous SiO2. The doping method has high deviation and needs to compound standard sample, while some kinds of pure minerals are hard to get. On the basis of summarizing researches have been done, a new method that combines QEMSCAN and XRD is proposed for the issue of amorphous SiO2 calculation in multiphase system. The new method avoids the flaws in approaches have been proposed, and calculates the amount of amorphous SiO2 indirectly according to the quantities of quartz and SiO2 measured respectively.According to QEMSCAN 650F integrated with XRD and gravity drainage method, we can calculate the mass percentage of amorphous silica, and the mass percentage of amorphous silica of YQ8 sample is 7.75%.
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The Exquisite Comparison of Shale Reservoir Characteristic Between Chang 7 Member and Chang 9 Member in Yanchang Formation
By L.G.H liuThe purpose of this article is to provide awareness of the subtle difference among these three sections shale.In order to figure out the exquisite distinction, nearly 200 samples have been used in a series of integrated and repeatable methods, including XRD, SEM-EDS, trace elements analysis, TOC and ROCK-EVAL.II Methodology, Vitrinite reflectance analysis, N2 adsorption analysis, CH4 adsorption analysis, and rock property analysis.
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Experimental Measurement and Mathematical Model for Intrinsic Permeability of Tight Rocks and Shale at Low Pressure
More LessGas flow in porous media differs from liquid flow due to the large gas compressibility and the klinkenberg effect. Klinkenberg effect is not negligible when the pressure is low or the permeability of the reservoir is very small. Enhancing the backpressure could eliminate the klinkenberg effect. However, high pressure is not always accessible under the lab or field production condition. As intrinsic permeability is important not only for the reservoir simulation but also for the theoretical study of gas flow in unconventional reservoir, a new method for determining the intrinsic permeability of tight and shale rocks was developed, excluding the effect of klinkenberg via both experimental measurements and numerical calculation. The steady state measurements were conducted with high purity helium. A mathematical model was then derived to determine the intrinsic permeability based on the measured gas fluxes and pressure profile. To test the presented method, extra measurements were conducted for methane flooding on three shale cores at low outlet pressure (lower than the minimum backpressure), showing good agreement with the data obtained from our model. The advantage of the method lies in two points: one is that the results are much more accurate than that from traditional PPD method when error exists in the existence of klinkenberg effect. This advantage is especially significant for tight and shale cores because the extra low permeability makes the effect of klinkenberg effect non-neglected. The other is that this method could be applied to any outlet pressure excluding the effect of klinkenberg effect.
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Problems of a Choice of Profitable Hydrated-Gas Accumulations for Operation
By A.S. BabaevDiscovery in water areas of the seas, oceans and some lakes of set of deposits of gas hydrates and their detection confinedness to areas with the raised values of geothermal fields have made a choice of criteria of search of the deposits most favourable to working out especially actual. Thereupon the author makes a number of the requirements, which performance at a choice gas hydrates deposits will allow to make gas production of it profitable. It is found out that to these conditions more all corresponds to a deposit of the hydrates generated by griffons functioning throughout a long time interval of operating underwater mud volcanoes. On the basis of calculations it is proved that thickness of layers of hydrates this deposits depends on volume of gas emissions of a griffon, and also depth of the sea on which there are griffons. The area of sedimentation of hydrates round a griffon at 20-50 time is less than flood area breccia during eruption also does not exceed first tens hectares. It is shown that process of thermal destruction hot breccia the rest which has generated for years of a volcano of a hydrated-clay layer does not change essentially volume-mass indicators of this layer
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The Stability of the Horizontal Wellbore while Drilling the Bazhenov Formation in Western Siberia
Authors E.A. Gladkov, E.E. Gladkova, E.G. Karpova and N.E. PulkinaThe results of studies of the behavior of core samples graded among ULTRADRIL, KCl-POLYMER, as well as in fresh water. The results of studies of the behavior of core samples fractionated in a medium Ultradril, KCl-Polymer, and also in fresh water showed complete inertness breed. Actual data proved that for horizontal drilling in different types of drilling mud will be mainly mud weights, instead of its formulation. It should be an in-depth study of geomechanical drillings rocks, with mandatory corin
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3D Geological Modelling Methodology for Unconventional Reservoirs of the Bazhenov Formation
Authors A. Telnova, V. Baranov, N. Bukhanov and P. BeschasovaThe Bazhenov is been researching during more than 50 years, but up to now the petroleum potential, optimal STOIIP or resources estimation approaches, reservoirs selection, petrophysical properties definition methodology are not clear. Distinctive features of bituminous shale are specific geochemical properties which were chosen as base parameters for the Bazhenov deposits geological modelling and key areas recognition. Main objective of this paper is choosing optimal algorithm of 3D geological modelling and testing it with conventional (petrophysical) and specific (geochemical) properties.
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Classification of the Bazhenov Formation Using Well Logs (R Field)
Authors D.A. Simonov, V. Baranov, N. Bukhanov and P. BeschasovaThis paper consider the main aspects of the Bazhenov formation interpretation and applying of machine learning algorithms in cases a of Kolpashev type section of the Bazhenov formation. Application of automatic algorithms of classification which would transfer the scale of research from small to large. Machine learning algorithms help to interpret the Bazhenov formation in reference well and in the other wells. During this work the unsupervised and supervised machine learning algorithms were applied to interpret the lithology and reservoir properties. This greatly simplifies the routine problem which deals with manual interpretation and has an economic effect deal with cost of laboratory analysis.
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On the Selection of the Optimal Mode of the Wave Stimulation in Oil Production
Authors E.A. Marfin, A.A. Abdrashitov and Y.I. KravtsovThe work dedicated to the problem mode selection of the wave stimulation to improve the efficiency of oil extraction. The method of combining with wave action by SAGD with two-wellheads reviewed. The process of formation of standing waves in the injection well and the energy propagation of elastic vibrations into a producing reservoir through the wall of the well is investigated. The existence range of the exposure frequency, at which there is minimal absorption of elastic waves, is set. It is shown that with increasing distance from the injection well a value optimum frequency shifts downwards. Obtained results may be the basis for selecting the optimal frequency wave stimulation.
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Genesis and Geological Structure of Oil Pools in the Sediments of Abnormal Bazhenov Formation Section
Authors V. Grishkevich, V.K. Kasatkin, S. Lagutina and E. PaninaThe article describes the concept of genesis of sand and silt bodies in the anomalous section of Bazhenov formation (ASBF), which is represented as postsedimentary gravitational displacement and plastic deformations of sedimentary rocks on the slope of Neocomian sedimentary side fill basin. Practical examples of the oil deposits in areas ASBF are shown.
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Features of Lithology and Geochemistry of Organic Matter of the Bazhenov Formation Pavlovskaya Area with the Use of GIS
Authors I.A. Zhigulsky, V.G. Eder, I.S. Sotnich, E.A. Kostireva and M.A. HalikovaLithological, geochemical and geophysical parameters of the Bazhenov Formation were analyzed in the poorly studied region in the south of the South-Nadimskaya megamonoclise on the Povhovskaya area. The bottom-to-top sequence of the Bazhenov Formation in this region is composed of 4 patterns: siliceous mudrocks – kerogenous siliceous mudrocks – clayey-siliceous mudrocks carbonate-siliceous mudrocks with carbonate lenses. These lithotypes differ by TOC values. GIS data of the studied section were comparing with the core. According to the cross-plot modeling (GIS-GIS ratios) 4 types of rocks were distinguished, that are characterized by their own area of parameters distribution. No differences were revealed in the lithotypes by biomarker parameters. According to geochemical parameters organic matter is related to the II type of kerogenous, that is aquagenous, and correspond to the main oil formation stage. In general Bazhenov Formation rocks characterized by low porosity (0,32-2,32 %). The structure of the Bazhenov Formation section of the studied region in general looks like to the Salum region sections. In the investigated area in the Upper Jurassic-Lower Cretaceous period hemipelagic conditions occurred. Reduced conditions distinguished during sedimentation and diagenesis. Both these factors controlling high concentrations of TOC in sediments.
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Forecast of Perspective Areas in the Oligocene Deposits Using a Comprehensive Analysis of Geological-Geophysical Data
Authors Y. Varov, F. Bars, O. Karamisheva and O. SivalnevaBased on the integrated analysis of a comprehensive geological and geophysical data lithological and geophysical characteristic of the Oligocene rocks was formed. It is the basis for the forecast of potentially productive interval distribution in the Khadum horizon and Batalpashinsk formation. These intervals are characterized by a low clay content, high brittleness and fracturing. Determination their distribution allows to predict of perspective zones for prospecting and exploration areas. The integrated geological and geophysical analysis approach may be applied to study of unconventional reservoirs within other areas of the North-Caucasian oil and gas province.
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Updating of Geological Oil and Gas Zonation of the Russian Federation (Onshore and Offshore)
Authors V.S. Shein and A.A. KnipperThe advantages of zonation based on using plate tectonics are given in this work. «Trial map of geological oil and gas zonation of the Russian Federation (onshore and offshore) based on using plate tectonics» is proposed. The comparison of traditional and new zonation methods is given.
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Tectonic Structure of the Conjunction Zone of the Laptev Sea Shelf and the Siberian Plate (From the Finding of 2D CDP Reflection Seismic Studies of 2013 - 2014)
By Y. VasilyevaBased on 2D CDP reflection seismic studies conducted by JSC SEVMORNEFTEGEOFIZIKA in 2013 – 2014, the tectonic structure of the northwestern part of the conjunction zone of the Laptev Sea shelf and the Siberian Plate was studied. Disjunctive dislocations were revealed on time seismic sections of the Laptev Sea shelf, i.e. dip-slip faults that had led to the formation of horsts and grabens. Within the Siberian Plate, dip-slip faults, reverse faults and overthrust reverse faults were observed, forming flower structures. The conjunction zone of the Laptev Sea and Siberian plates includes the continuation of the South Taymyr fold zone with overthrust reverse faults. In the southeastern part of the area, the conjunction of the Laptev Sea and Siberian plates is represented by a series of reverse faults and a high-amplitude regional dip-slip fault. The following tectonic elements were revealed in the revised schematic tectonic map of the Laptev Sea and northwestern margin of the Siberian Plate: the Lena-Anabar marginal zone with South Taymyr High and the Kharaulakh Marginal Zone. It was assumed that the South Taymyr High and the Kharaulakh Marginal Zone are divided by a regional oblique-slip fault on the continuation of the Khatanga-Lomonosov transform fault
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Features in the Sedimentation and Organic Geochemistry of the Lower Toarcian Clays in Northern Eastern Siberia
Authors E.A. Fursenko, B.L. Nikitenko and V.G. KnyazevRecently the interest is increasing to the Arctic region, which are regarded as the areas with significant hydrocarbon resources. So the important task is the comprehensive geological and geochemical studies in the Arctic to identify enriched dispersed organic matter, a potentially oil source strata. As is well known the crisis events in the biosphere (eg T-OAE) are most favorable for the formation of such sequences. It has been shown that T-OAE had a significant impact to features on Pliensbachian - Toarcian clay strata exposed in outcrops Kelimyar River (the Olenek river district, Eastern Siberia).
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Tectonic and Paleogeographic Conditions of Anadyr Trough Petroleum Systems
Authors E.A. Lavrenova, N.A. Malishev, V.V. Obmetko, A.A. Borodulin and A.A. GorbunovBasin analysis as well as petroleum system modeling within Anadyr trough have been performed. It was revealed that Anadyr trough includes several sedimentary basins with different development. These differences determine petroleum system evolution and therefore Anadyr trough oil and gas prospects
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Geological and Geophysical Criteria for Identifying Zones of Productivity Bazhenov Formation of the Salym Group of Field
Authors S.I. Bilibin, A.V. Vovk, T.F. Diakonova, T.G. Isakova and E.A. YukanovaThe proposed indirect geological and geophysical criteria for identification pale geological signs with the current state of the Bazhenov formation. Geological properties of the Bazhenov formation, due to conditions sedimentation, structural factors, the temperature of the reservoir and other. The quantitative basis for the division of indirect criteria for grading is their comparison with the accumulated oil production and the ratio of the specific productivity of the wells.
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Multiple-Point Geostatistical Modeling with Training Images
By M.S. VolkovaIn this paper, some aspects of practical application of multiple-point statistical simulation are considered. Multiple-point simulation is aimed to overcome the certain restrictions, which exist in classical geostatistics. Methods of multiple-point geostatistics include an ensemble of sequential simulation algorithms which use the training image as input data for the description of spatial structure of geological object. The results of modeling with various training images are presented. The next kinds of training images were used: stationary, nonstationary, categorical (for facial modeling), continuous (for modeling of effective thickness). In the DV-Geo module of multiple-point statistics the Direct Sampling algorithm (Mariethoz et al., 2010) is realized. It is possible to say that Direct Sampling algorithm successfully operates on fields with small and large number of wells. The demanded computer memory and CPU time do not depend on the volume of well information
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The Studying of Features of Reservoir Pressures in Area of Yamal-Nenets Autonomous District
Authors P. Gorbunov and S. VorobyevAuthors describe the features of changes of reservoir pressures at oil and gas fields of the Yamal-Nenets Autonomous District. This research based on the results of hydrodynamic and thermometric studies in prospecting and exploration wells of Yamal-Nenets Autonomous District. In the Cenomanian, Albian, Aptian and in the top of Neocomian deposits, according to research, reservoir pressure usually equal to hydrostatic pressure. At the bottom of the Neocomian and Jurassic deposits set zones with abnormally high reservoir pressures within Gydan and Yamal Peninsula and in the Nadym-Pur-Taz interfluve. The results of the survey should improve the efficiency of exploration drilling by preventing complications and accidents during this operation in zones with abnormally high reservoir pressures.
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Regional Patterns of Porosity Evolution During Diagenesis of the South Barents Basin
Authors P.O. Sobolev and M.A. LavrentevaThe porosity studies results of the sedimentary rocks from the South Barents Sea Basin are discussed. The porosity was estimated by several methods including well logging analysis and core measurements. As a result of the research generalized porosity trends with depth were obtained for the upper part of the basin (about 3-4 km). Main factors affecting the porosity and permeability of siliciclastic rocks were assessed. The greatest influence on the porosity has a compaction (depth). Also, both porosity and permeability depend on the cement type and grain size. These patterns have been used to study the processes of diagenesis, estimation of uplift/erosion, basin burial and petroleum systems modeling.
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Hydrocarbon Potential of Izhma-Pechora Basin and Adjacent Pechora Sea as a Result of Basin Modeling
More Lesshis is the first work summarizing old and new geological and geochemical data on the working area. The results of 1D, 2D and 3D basin modeling give us a forecast for the hydrocarbon potential. Main source rocks were determined, directions of migration were traced. A forecast for accumulation was given.
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Petroleum Potential of Marginal Parts of the Timan-Pechora Sedimentary Basin
Authors O.M. Prischepa and O.V. ChumakovaThe Timan-Pechora sedimentary basin is characterized by complex geological structure and uneven geological and geophysical level of study. The lowest level of study belongs to its marginal parts - junction zones with Pre-Ural trough on the east and Timan ridge on the west. The exploration performed in recent years on the basis of the state budget programs has made it possible to clarify the prospects, reestimate hydrocarbon resources, identify new areas of exploration and priority objects for further exploration. The unity and continuity of the geological structure in the junction areas of land, transit zones and waters are proved. The extensive development of pre-Devonian sediments complexes, including the Vendian - Late Riphean is revealed that led to rethink the age of the basement in the western part of the basin.
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Substandard Carbonate Reservoirs of the Timan-Pechora Oil and Gas Province and Their Development Prospects
More LessCurrently, up to 75% of recoverable oil reserves of the oil balance of the Russian Federation are characterized as hard-to-recover. The biggest part of these reserves are concentrated in low-permeability reservoirs - up to 44%. The largest hydrocarbon deposits of the Timan-Pechora province have been explored and are in development. The oil reserves growth from newly discovered fields (most of them are small) does not renew extracted oil and gas. The hard-to-recover oil resources are already dominated in the structure of the mineral resource base of the Timan-Pechora province. The oil extraction of hard-to-recover resources is increasing due to the application of modern technologies, however the rate of growth of these reserves exceeds the rate of production. A large proportion of hydrocarbons confined to the deposits with unfavorable reservoirs remains unrecovered regardless of the mode of development. High rates of development of scientific and technical ideas in petroleum geology allow us to pass to the development and exploitation of carbonate reservoirs with substandard parameters of porosity and permeability through integrated high-tech methods of development, which makes it possible to substantially increase the resource base of hydrocarbons in areas with developed oil infrastructure. Involvement of substandard reservoirs in the development requires new approaches to their prospecting and forecasting. In order to identify criteria for the forecast of such objects a comprehensive study of rocks with low permeability reservoir parameters should be carried out at different depths by means of geological, geophysical, lithological and petrophysical methods.
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Features of Geological Structure Oligocene Deposits of the East Ciscaucasia
Authors A.V. Postnikov, Y.V. Lyapunov and N.A. OsintsevaThe paper studies the Oligocene deposits of the Eastern Ciscaucasus which are promising in the search for oil and gas. A geological model of Oligocene deposits is proposed based on cyclostratigraphic analysis with potential reservoir-rocks confined to the thin layers of turbidites.
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Ways of Growth Hydrocarbon Resources in Russia
Authors V.L. Shuster, S.A. Punanova and A.V. SamoilovaPerspective directions of exploration are suggested to increase oil and gas resources in Russia. Criteria for evaluation of these directions are proposed to select the priority of them in the short and medium term.
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Geological Structure of the Predsettedaban Trough
By I.N. NafikovThe geological structure, main tectonic elements and the nature of distribution of major units of the fill of Predsettedaban trough are analyzed on the basis of the newest data obtained. Newest data was reprocessed by specialists of VNIGRI and OAO Yakutskgeophysika. This area is the southeast boundary of link structures of the Siberian platform. Major tectonic elements of the region is the Aldan-Maya depression. Depression was formed in place pericratonal deflection on eastern edge of Aldan anticlise. On top of foundation Aldan-Maya depression is a monocline submerged under Verkhoyansk-Kolyma fold-thrust system. Foundation of the region represented deep-metamorphosed rocks of Archaean. Sedimentary fill composed by four structural tiers: Proterozoic(?)-Lower Riphean, Riphean, Vendian-Cambrian and Mesozoic. Riphean deposits have interesting petroleum potential prospects.
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Litho-Facial Reconstructions of the Upper Jurassic Deposits in the Central and Southern Parts of the W. Siberia Basin
Authors I.S. Nizyaeva, V.V. Shimansky, N.V. Taninskaya and N.N. KolpenskayaPotentially productive Upper Jurassic (Oxfordian) deposits widely distributed in the eastern part of the Khanty-Mansi Autonomous Okrug and the north-eastern part of the south Tyumen region have been investigated using multidisciplinary approach, which allows recognition of structural feathers of reservoirs and reconstruction of sedimentary basin evolution. On the basis of detailed setimenthological core description, interpretation of LOGs and complex analyses of obtained laboratory results 7 characteristic facies have been determined: channels, proximal and distal deltaic fans, barriers, coastal plain, offshore and shelf. Then litho-facial map of the Oxfordian was constructed in coordination with 2D and 3D seismic data. Channels, proximal deltaic fans and barriers facies distributed in the eastern and western parts of the Khanty-Mansi Autonomous Okrug and the north-eastern and central parts of the south Tumen region are considered to be most perspective for hydrocarbon sources.
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Guided Waves Leaking From High-Velocity Elastic Layer
Authors P.E. Znak, B.M. Kashtan and V.N. TroyanGuided waves comprise relatively fast leaking modes and have the potential for P-wave velocity inversion. That is the reason for the geophysical prospecting community to pay more and more attention to them. Nonetheless, described by frequency dependent complex roots within the Riemann surface of multivalued dispersion equation, they still remain unstudied even for models with one plane-parallel elastic layer. The property of guided waves to demonstrate the frequency tuning effect in case of a waveguide is known. Recently, we succeeded in an accurate numerical calculation of the leaking modes dispersion and attenuation curves with the help of the so-called outpost method. It turns out that the guided waves leaking modes complex slowness oscillate near the correspondent acoustic solution for normal modes in case of close to 1/2 Poisson ratio inside the layer. Here we replace the material parameters of the layer by the material parameters of the environment and check if there is any similar behavior of the leaking modes in case of a high Poisson ratio outside the layer.
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Statistical Analysis of Free-Surface Variability's Impact on Seismic Wavefield
Authors D.R. Kolyukhin, V.V. Lisitsa and V.A. TcheverdaOne of the main challenges in seismic monitoring is the repeatability of the experiment conditions. Among other reasons changes in surface topography over time may cause strong non-repeatability in acquired seismic data especially in desert environment where the sand dunes can move between surveys. In this paper we present a numerical study of the effects of free-surface variation, defined as homogeneous Gaussian random field, on the seismic data. We show that for homogeneous models repeatability metrics (such as NRMS and predictability) using the early arrivals as measured by buried receivers depend mainly on the perturbation, but not on the smooth trend of the free–surface topography. For models with complex near-surface velocity NRMS for the thin sand area (<5 m) is almost twice as high as in the thick sand area (>10 m). Moreover, we demonstrate that significant non-repeatability (NRMS up to 70%) can be caused by just surface elevation changes.
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Poroelastic seismic modeling to study the implications of mesoscopic-scale fluid flow
Authors R. Wiley, S.W. Peters and P.H. WilsonWe investigate the effect that fluid flow in a porous medium has on seismic reflection data. By using a mesoscopic-scale poroelastic model for the attenuation effects in the fluid filled porous layer, we are able to construct seismic traces which exhibit the effects of poroelastic layers. The results are seismic data which show changes in frequency and phase due to the presence of the mesoscopic-scale heterogeneities.
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Use of Discontinuous Grids for Solving Helmholtz Equation in Complex Models
Authors A. Zaitseva, V. Lisitsa and S. SolovyevIn this paper, we consider 2D Helmholtz equation with complex shift and assume it to be solved using domain decomposition technique where finite-difference method on fine and coarce meshes applied in the upper and lower parts of the model respectively. We proved that the use of different grids leads to nonsymmetrical perturbation of the original operator, thus causes the irreducible error in the solution – artificial reflections from the boundaries of the subdomains, even though the residual tends to zero exponentially with respect to the number of iteration.
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Direct Problems in Seismic Data Processing and Interpretation
Authors D.B. Finikov, S.A. Kaplan, E.B. Lebedev and A.V. ShalashnikovThe solution of direct problems in the process of seismic data processing and interpretation is an important element which determines the information capability of the method in the specific seismic environment and with the account of the specific geological objectives. It is used at the stage of the choice of a seismic acquisition design, seismic processing sequence, the type and the content of seismic record attributes, as well as the correctness of the obtained results (structural models, the forecast of lithofacial characteristics of deposits, prospective oil & gas deposits and their reservoir properties). In addition, only the processing and interpretation of wave fields synthetic data may help to determine the real possibilities of Geophysics for the specific region. The usage of different solutions of direct problems, including the calculation of synthetic seismograms, is explained in this paper. The authors show the results obtained under the conditions of salt tectonics with the usage of complex processing sequence, including wave fields transformation procedures (such as datuming & redatuming).
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Cluster Implementation of Low-Rank Multifrontal Direct Solver for 3D Helmholtz Problem
Authors S. Solovyev, V.I. Kostin and D. VishnevskiyThe modern methods of processing the geophysical data, such as Reverse Time Migration (RTM) and Full Waveform Inversion (FWI) require solving series of forward problems where the main step is solution of Systems of Linear Algebraic Equations (SLAE) of big size. For big sizes, it is time and memory consuming problem. In this paper, we present a parallel direct algorithm to solve boundary value problems for 3D Helmholtz equation discretized with help of finite differences. The memory consumption has been resolved due to Nested Dissection approach, low-rank approximation technique and HSS format. OpenMP parallelization is based on standard BLAS and LAPACK functionality. For MPI parallelization, we propose a novel algorithm that uses dynamical distribution of the elimination tree nodes across cluster nodes. Numerical experiments show performance benefits of the proposed cluster algorithm compared to the not parallel version and demonstrate significant memory advantages over direct solvers without low-rank approximation.
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Numerical Simulation of Sonic Log for Anisotropic Media
Authors G. Reshetova, V. Lisitsa and V. TcheverdaIn this paper we present an efficient and accurate numerical algorithm for simulation of sonic logging experiments. The basis of the approach is a heterogeneous finite difference method applied to acoustic-elastic wave equation written in velocity-stress formulation. The approach was designed to simulate wave propagation in 3D arbitrary anisotropic elastic media with attenuation. Moreover due to universality of heterogeneous finite-differences the algorithm allows to handle with surrounding models of extreme complexity. We also present and discuss results of simulation for arbitrary anisotropic inhomogeneous models.
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A Finite Element Method Whose Shape Functions are Constructed Thanks to a Boundary Element Method
Authors H. Barucq, A. Bendali, M. Fares, V. Mattesi and S. TordeuxThe numerical solution of wave propagation problems on very large domains (with respect to the wave length) is a very challenging problem. This is particularly true in the context of three dimensional problems where the large number of degrees of freedom can rapidly exceeds the capacity in storage and in computing even in the framework of massively parallel computer platforms. For time harmonic wave equation, classical volume methods suffer from the so called numerical pollution effect. Roughly speaking, it is necessary to augment the density of nodes to maintain a given level of accuracy, when increasing the size of the computational domain. This is mainly due to a bad approximation of the speed of propagation of the wave. However, these methods are well adapted to heterogeneous media. Numerical methods based on integral equation formulation, like boundary finite element method, do not suffer from the pollution effect since these technique are based on the evaluation of the Green function which contains exact information about the phase. In contrary, these techniques are hard to implement for heterogeneous media. During this talk we would like to present a numerical method which benefits from the advantages of both methods: low pollution effect and ability to handle heterogeneous media.
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3D Gaussian Beam Imaging of 3D3C VSP Data
By M. ProtasovThe approach to true amplitude seismic imaging for 3D Vertical Seismic Profile (VSP) three component data is presented and discussed. This approach is migration procedure based on weighted summation of prestack data. True amplitude weights are computed with application of Gaussian beams. In order to get difraction image these beams are taken in a way forming so called selective images. Their geometry provides suppression of regularly reflected waves and, thus, emphasizes the presence of small-scale heterogeneities that give rise to diffracted/scattered waves. The use of P- and S-wave Gaussian beams provides the possibility to handle raw multi component data without of their preliminary separation to PP and PS waves.
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Efficient Deflection Angle Based Filtering for Waveform Inversion
Authors V.V. Kazei, E. Tessmer and T. AlkhalifahThe importance of accessing the scattering angle information has been recognized in ray-based applications a long time ago, but only recently became available in the field of wave equation based imaging and inversion. First it was implemented for wave equation migration velocity analysis, then reverse-time migration and finally full-waveform inversion. Conventional access to the scattering angle information in seismic imaging via wavefield continuation requires an extension either in space or in time, which is costly in terms of computational resources. For a single frequency this filtering can however be interpreted as a non-stationary convolutional filtering, which is expensive in general, but more so in 3D models. To obtain a more efficient scattering angle filter, we develop techniques that utilize the mapping nature (no domain extension) of the scattering angle based filter for constant-velocity background models. We split the background velocity model into regions with different velocity ranges, generating an "extension in velocity", so that in each region the velocity is assumed not to vary much. A numerical example demonstrates that a few samples in the newly introduced dimension is enough to apply the scattering angle filter. The filter can be utilized either for full-waveform inversion preconditioning or to clean up reverse-time migration artifacts. A novel interpolation is obtained by splitting the background velocity model with a smooth decomposition of unity
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Diffraction imaging of fault facies models
Authors M. Protasov, D. Kolyukhin, D. Qu, V. Tchevreda and J. TverangerSeimic data represent a largely untapped source for characterising of fault zones. The key for using it lies in linking fault zone structure and properties to seismic response. The recent development of outcrop-based fault zone models allows this links to be studied. A seismic imaging procedure for fault zones, using multicomponent surface data generated for statistical fault facies models, is presented and discussed. It is based on a specific imaging procedure, which consists in a weighted summation of multicomponent multishot/multioffset data and spectral filtering of seismic data. The imaging procedure presented here is capable of resolving details inside the fault zone, which opens up for using seismic data to characterize sub-surface faults.
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Uncertainty from Grain Scale to Reservoir Scale
Authors B.T. Wells, O. Hinds, R.A. Duller and R. WordenThe usefulness of reservoir modelling, and Earth modelling in general, is being significantly enhanced through incorporation of uncertainty analysis. Indeed the acceptance of geostatistics in general within the oil and gas industry relies largely on the ability of geostatistics to combine modelling of uncertainty with traditional modelling: the best prediction of values. This combination is accomplished by treating variance as a primary variable which has implications for those responsible for data collection. We seek to identify useful data collection strategies and highlight the changes necessary if data are to be used to model uncertainty in reservoir models.
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The Criteria of Decision-Making with Account of Risk and Uncertainty in Petroleum Exploration
Authors V.I. Poroskun and N.M. EmelyanovaThere are following criteria which are usually used while decision-making in petroleum exploration
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Evaluation the Value-of-Information (VOI) and Look Back Analysis During Modelling of the Exploration Works
Authors D.N Peskova, A.V. Sizykh and V.S. RukavishnikovPaper deals with actual problem about making decisions while development of the field. The main aim was to apply method ''Value of information'' in order to estimate the necessity of exploration works for the field and show the effectiveness of this method. The object of analysis - field X, which is located in the Eastern Siberia. The reservoir is B13 formation of Vend age. Field has complex structure, and divided into blocks by faults. During evaluation of the project, main uncertainties and oil in place were obtained for three blocks of the field. According to uncertainty analysis, it was suggested to drill new exploration well, and value of information method was applied to estimate results from this exploration works. Economic evaluation the value of information was made on the base of choosing optimal development strategy. According to the obtained results, drilling of the exploration wells for blocks 1 and 3 of the field X is a good decision, while drilling of a well in the second block is risky and not recommended. Also using the value of information, optimal well locations were advised – well 1_1e for the first block, and well 3_3 for the third block.
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Probabilistic and Statistical Model for Evaluation of Geological Uncertainties Influence on Project Economics
Authors M.V. Naugolnov, A.A. Borodkin, N.F. Teplyakov and M.S. BolshakovThis paper is dedicated to determination of the value of geological uncertainties and risks influence on project’s economic efficiency. Particularly, the developed software that is able to provide the full cycle of probabilistic and statistical oil field development evaluation is considered. The cycle of evaluation includes STOIIP estimation, reservoir evaluation (on depletion) and project’s economic evaluation
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A Stochastic Analysis of Value-of-Information Derived From Petroleum Systems Modelling
Authors A. Beha, G. Martinelli, D.A. Surovtsev and S.S. HuseinThis paper proposes a methodology to assess the value added to a prospect assessment through information provided by basin and petroleum system modeling methodology. The effects of a more detailed petroleum system model on a prospect assessment are usually more difficult to evaluate than the effect of new 3D seismic surveys on exploration prospects since the information provided by a BPSM has primarily a basin- or a play-wide extent. In order to evaluate potential benefits of a BPSM consistently we start by studying and evaluating in detail the ability of BPSM to predict hydrocarbon accumulations in a known (benchmark) basin. Second, we evaluate and quantify the sensitivity and specificity of this information in order to have a probability measure that could be generalized. Third, we apply such measurements to the assessment of the studied prospect in an analogue basin in order to calculate the revised geological chance of success. Fourth, we evaluate the impact of this revision on NPV through a full cycle analysis using a hypothetical development plan of the prospect to come up with a Value of Information assessment.
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Selection of the Optimal Regular Development Scheme under Conditions of Considerable Geological Uncertainties
Authors A.F. Nazmutdinov, A.P. Roshchektaev and V.N. SibilevThe objective of this project is to choose optimal development scheme of block Z Field Y that is stable for uncertainty in geology. “Optimal” here means “optimal in the mean” that brings the highest EMV. Absolute permeability field and relative permeabilities curves were chosen as uncertainties to investigate. Three relative permeability curves and three fields of absolute permeability were chosen, i.e. totally 9 geologies were involved in selection of the optimal development scheme process. Many calculations of various development schemes for each geologies (absolute and relative permeabilities) were made. Optimal completion type and well pattern were determined. Then there was an attempt to create NPV proxy model by means of spline approximation and artificial neural network. Both methods, based on 27 points for training showed poor results, that is number of training data points (simulation runs) should be increased to obtain satisfactory results. Obtained proxy models helps to assess influence of the Corey relative permeabilities’ parameters to production and therefore to the NPV.
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Integrated Sedimentological Analysis: a Key Approach for Volumetric Evaluation and Risk Assessment of Achimov Plays
Authors V.K. Piskunov, J. Rubino, S. Vitoux, T.S. Rychkova and O. SiccardiWidely spread in Western Siberia Achimov deposits are represented by fan complexes in slope and basin parts of Neocomian clinoform formation. Stratigraphic trapping plays a key role especially in areas outside of structural highs. Sequence stratigraphy analysis together with defining fan relationship with slope allows predicting main and intermediate seals effectiveness as well as reservoir position inside the clinoforms. Prediction of reservoir facies distribution combined with regional and worldwide analogs analysis also a key element for volumetric reserves evaluation. Defining of architectural elements such as lobes, slumps and channels helps to estimate reservoir geometry and range of key parameters (Gross&Net thickness, NTG, Porosity and Permeability). Thus complex sedimentological model based on logs, seismic, core and analogs analysis allows evaluating uncertainty range of parameters and probability of success especially in poorly well constrained areas. Such detailed approach resulted in identification of areas with reserves density above economic threshold. As a consequence exploration well drilling is now considered to prove the presence of developable reservoirs within the considered license.
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Studies of Mid-Jurassic Thin Beds in Conditions of Presence of the Anomalous Bazhen Suite (Shirotnoe Priobje Case)
Authors M.V. Skaryatin, A.V. Shubin, D.V. Klyazhnikov and V.I. RyzhkovAuthors propose guidelines for investigation of thin reservoirs in conditions of overlaying amplitude anomalies noise. The Mid-Jurassic rocks were deposited in different sedimentary environments. The lower part represents fluvial bodies deposited inland and in delta plain, and the upper part is transgressive shoreface sand. Small thicknesses of the sand bodies do not allow to be resolved in seismic due to the vertical resolution limitation. However, these bodies can be laterally resolved and mapped. The presence of coal beds and overlaying anomalous section of the Bazhen Suite complicates the interpretation. The proposed solutions include creation of the mask of the Bazhen Suite amplitude anomalies, combination of attribute analysis, inversion, Bayes probability classification and well data. The overlapped Bazhen mask with maps can filter the influence of the anomalous Bazhen Suite. As a result of the Bayes classification, the effective thickness map was formed. Shapes of the various attribute anomalies underline the lateral distribution of sand bodies and help in tracing of those. Well data provided facies control of the identified sand bodies. The applications of the proposed methods cover Shirotnoe Priobje region and other fluvial systems around the world, which are prospective in terms of discoveries of hydrocarbon accumulations.
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Jurassic and Cretaceous Tectonic Evolution of the Demerara Plateau – Implications for South Atlantic Opening
Authors K.C. Casey, A.K. Krueger and I. NortonThe Demerara Plateau is located on the northeast South America continental margin between 5° and 10° North, marking the northwest corner of the equatorial segment of the Atlantic Ocean. It is conjugate to the Guinea Plateau on the African margin which rifted from the Demerara during the Early Cretaceous opening of the Central Atlantic. Published studies of the Demerara Plateau are focused on its Cretaceous history, when the northern edge of the platform was formed by trans-tensional deformation along Atlantic transform faults, and its eastern edge by extensional deformation during rifting. The platform itself is commonly interpreted as a continental block left behind following South Atlantic rifting. Seismic data across the plateau reveal significant compressional deformation beneath an Albian unconformity. We suggest that this deformation is the result of early opening of the South Atlantic, with a rotation pole located close to the present-day Amazon delta. Allowing for this compression in plate reconstructions of the South Atlantic results in restorations which do not require large amounts of intra-continental deformation in South America, and consequently in a relatively simple plate model for the South Atlantic
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Prediction the Relative Changes of the Reservoir Permeability
Authors E.A. Korolev, A.I. Rozhkova, A.A. Shevchenko, K.A. Smirnov and G.M. GoloshubinTraditional approach to predict reservoir properties involves map construction of the expected net thicknesses and porosity on the base of attribute analysis of the wave field and inversion results. The reservoir permeability is an important parameter for field development and its forecast on the base of seismic data analysis is not widely spread, although there are publications that illustrate the possibility of such forecast. The article presents the results of applying the frequency-dependent seismic attribute, which can be characterized as an indicator of fluid mobility and may represent the relative changes in the reservoir permeability. This attribute aimed at detecting of frequency anomalies in the spectrum of the wave group, reflected from porous fractured reservoir. In accordance with analytical solution the changing of the attribute values along the reflector indicates the proportional variation of the reservoir permeability.
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