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5th EAGE St.Petersburg International Conference and Exhibition on Geosciences - Making the Most of the Earths Resources
- Conference date: 02 Apr 2012 - 05 Apr 2012
- Location: Saint Petersburg, Russia
- ISBN: 978-90-73834-23-1
- Published: 02 April 2012
1 - 100 of 178 results
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Overview of the Cretaceous Evolution of the North-western Barents Sea
Authors A. Escalona and S. OlaussenThe northwestern Barents Sea is mostly under explored and covers a large part of the Norwegian and Russian continental margins. Most reservoirs are Carbonifeours to Jurassic in age, and little attention has been paid to the Cretaceous intervals which may hold enormous potential. After the newly discovered liquid petroleum system in the western margin of the Barents Sea (i.e. Skrugard) the link between the conjugate margin offshore North East Greenland and western Barents Sea becomes of particular interest. In addition, the northern boundary of the Cretaceous interval represents a key transition time in the evolution of the northern Arctic region which affected large areas of the Barents Sea and was the time where most of the North American arctic basins developed. Plate tectonic models during this time are quite uncertain due to the lack of constrains, but until the late Jurassic/early Cretaceous, most arctic basins seem to be related. In this presentation, an overview of the Cretaceous evolution of the Arctic, with focus on the plate setting of the northwestern Barents Sea is provided in order to highlight areas that require further analysis to evaluate the petroleum potential.
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The History of Development and Prospectives of the Jurassic Deposits on the Barents Sea Shelf
Authors A.A. Suslova, A.V. Stoupakova, Y.K. Burlin and R.S. SautkinReservoirs of Jurassic complex in the Barents Sea sediments were formed under transgressive-regressive regime of sedimentation in the midst of the marine basin’s general transgression. In Jurassic time eastern and western sectors of the Barents Sea basin developed as a single basin under calm tectonic environment. This gives the possibility to identify general sedimentation cycles within the limits of this region.
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Geological Structure and Petroleum System of South Kara Basin
Authors N.A. Malyshev, V.A. Nikishin, V.V. Obmetko, B.I. Ikhsanov, Y.V. Reydik, K.A. Sitar and D.S. ShapabaevaGeological model of South Kara basin (SKB) based on 2D seismic and regional lines 2-AR and 3-AR. The SKB is filled by Upper Triasic(?)-Cenosioc clastic sediments together with the Late Permian(?)-Mid Triassic synrift megasequence. The rifts base is tracked at the depth up to 11-12 km. Using new seismic data, we identify grabens and semi-grabens at the base of the basin. They are filled by partly deformed sediments. The 3D basin model is done and shows oil and gas windoows. Many structures identify on Paykhoy-Prinozemelskiaya monokline such as Universitetskaya, Vikulovskaya and Tatarinovskaya.
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Constraints on Magnitude of Cenozoic Uplift and Petroleum Systems Modelling for the Russian Barents Sea
By P.O. SobolevThe Cenozoic regional uplift remains very poor investigated for the Russian part of the Barents Sea. Several methods were used to estimate magnitude of the uplift and erosion for the Eastern Barents Sea. First method was related with using of generalized porosity-depth trends. Geophysical well logging data from the Russian Barens Sea (about thirty deep offshore wells) were compiled and processed. The joint interpretation of sonic, gamma-ray, resistivity, spontaneous potential logs were used to calculate porosity and shale fraction for siliciclastic rocks. Comparison of smoothed exponential porosity-depth curves from different wells reveals the rate of compaction for the different kinds of sediments (sands, silts and shales) and different level of erosion. Similar results were obtained with Magara’s approach for sonic logs of shales. We used vitrinite reflectance data for the independent evaluation of the uplift and for calibration. Combining the data on wells we have determinated uplifts ranging from 300 m in the south (Pechora Sea) to 700 m in the central part of the South-Barents deep and to 2 km in the Franz-Joseph Land. The magnitude of erosion increase eastward as well. Seismic profiles and structural maps were used to trace and interpolate the estimates of uplift between wells.
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Looking for the Giants - Sedimentation and Basin Modelling Application for South Kara Basin
Regional modeling approach including Sedimentation and Basin modeling had been applicated with use of Beicip Franlab software tools (Temis and Dionisos) in Kara Sea regional studies at Gazpromneft Science and Technology Centre. As a result of the modeling, the possibility of further discoveries of giant fields in South Kara Basin is pretty high. Although gas accumulations are predominating in the basin, oil-and-gas condensate fields with sufficient part of liquid hydrocarbons could be found in the areas where the source rocks facies and maturation is favorable. We assume that the main source for the hydrocarbons, accumulated in the South Kara Basin in Cretaceous reservoirs are the Uppermost Jurrasic, as well as Lowermost and Middle Jurrasic shales with mostly marine type of kerogen. Lower Cretaceous (apt-alb) sediments enriched in terrigenous organic matter and containing coaly layers never entered the “oil window”, so they could produce only shallow biogenic gas, which can’t be assessed quantitatively using basin modeling technique and may affect the pools, mixing with the thermogenic gas from Jurrasic source rocks. Further studies and new geological and geochemical data required to refine the model and make sure that the geological and geochemical model assumptions were correct.
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Lower-upper Permian and Triassic Seismostratigraphic Complexes in the South-eastern Barents Sea
Authors D.A. Norina, G.S. Kazanin, S.P. Pavlov and A.V. StoupakovaPresent evaluation of Lower-Upper Permian and Triassic clastic deposits in the Russian Barents Sea shelf are based on detailed geological and seismostratigraphic interpretation of regional seismic lines acquired by MAGE in 2007-2009. Active uncompensated subsidence of South Barents and pre-Novaya Zemlya depressions in Early-Late Permian and sea level changes led to the formation of three sequences in which low-stand, transgressive and high-stand system tracts were identified. Low stand system tracts infill central parts of the basin and contain high-amplitude discontinuous reflections which may indicate sandstones of basin fans. High-stand system tracts are characterized by sigmoid progradational reflection pattern with high-amplitude facies at clinoform bends corresponding to perspective shallow-water reservoirs. Pemian-Triassic erosion unconformity is well-traced at the basin margins. Triassic strata in the study area were formed in deltaic, coastal and shallow-marine conditions under constant compensation of basin subsidence with large volumes of sediments. They are characterized by hummocky high-amplitude reflection configuration at basin margins and low-amplitude sub-parallel discontinuous seismic pattern in the central parts. Bright, parallel, continuous reflections in the Middle Triassic correspond to sea level rise and shale deposition. Structural and stratigraphic traps were identified in Triassic complex.
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Hydrocarbon Potential of Riphean-paleozoic Deposits of Taimyr
By V.A. BaldinRegional 2D seismic explorations of enhanced depth were carried out at the beginning of XXI century for the first time. They allowed together with other geological-geophysical data fundamentally change the model of structure of Yenisey-Khatanga regional depression, Taimyr mountain area, Siberian Platform and Western-Siberian plate. New largest (of superorder and I-II orders) structural-tectonic units were defined on the north of Siberia. Hydrocarbon potential of north-east of Western Siberian, north-west of Siberian Platform and western part of Taimyr fold system was evaluated based on the new attitude. The new hydrocarbon potential sedimentary basin in Riphean-Paleozoic deposits (South-Taimyr oil-and-gas province) was defined on the southern part of Taimyr belt of thrust faults. On the north-west of Siberian Platform the Igarsko-Norilsk oil-and-gas province was defined where the main zones of potential oil and gas accumulation may be megabars with accessible for drilling Riphean-Paleozoic complexes.
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Hydrocarbon Systems of Tatar Strait Sedimentary Basins and its Prospective Production Analysis
More LessThe article discribes the main stages of the section hydrocarbon productivity forming. It is based on the generation and migration processes and their evolution during the geological history. The main result of the project is the new objects for exploration studies and phase composition prediction for the possible hydrocarbon deposit.
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Geological Prerequisites of Formation of Big Oil and Gas Centers in Eastern Siberia
Authors V. Kharakhinov and S. ShlenkinTheoretical estimates of oil-and-gas generation in East Siberia revealed by our complex analysis allowed us to draw a conclusion that oil-and-gas potential of East Siberia is underestimated.
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Using Onshore Geology to Predict the Hydrocarbon Potential of a Frontier Arctic Region - The Laptev Shelf, East Arctic
Authors J.S.K. Barnet, O.J. Ralph, C.M.J. Davies, A. Davies and M.D. SimmonsWith growing interest in the hydrocarbon potential of the circum-Arctic, increasing attention is turning to the frontier shelves of the East Arctic such as the Laptev Shelf. No deep wells have been drilled offshore, with stratigraphic predictions based on study of onshore outcrops, including the Taimyr Peninsula, northern mainland Siberia and New Siberian Islands. The discovery of hydrocarbon fields in Jurassic-Early Cretaceous clastics of the Yenisey-Khatanga and West Siberian basins, and in Permian-Triassic clastics of the Lena-Anabar Basin, highlight Late Palaeozoic-Mesozoic potential in the neighbouring offshore. Early Cretaceous post-orogenic and Late Cretaceous-Palaeogene syn-rift coal-bearing clastics could represent the most significant source rocks. Marine organic-rich facies of the PETM and Middle Eocene “Azolla” event may constitute oil-prone source rocks in restricted grabens. Oligocene-Early Miocene sandstones and Late Miocene-Pliocene marine shales could represent regional reservoirs and seals respectively. We have conducted a study of the region using a global sequence stratigraphic model, drawing on data available in the public domain. This interpretation allows enhanced understanding of the shifting distribution of transgressive and regressive reservoir facies. When placed in a regional palinspastic framework, models of source rock deposition can be developed, and used to better predict timing and extent of deposition.
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Carboniferous Paleogeography of North-eastern Siberia
Authors V. Ershova, A. Khudoley and A. ProkopievThe study area is located on the northeastern margin of the Siberian Craton. The Carboniferous time was marked by extensive transgressions with widespread distribution of marine deposits throughout the study area. The Carboniferous deposits show transition from deep see basin environment through distal prodelta environments to prograding deltaic (delta front and delta plain) environment. One of the main questions for this region is a source area for Carboniferous deposits of North-East Siberia. We are presenting here a provenance pioneer study based on detrital zircon dating. All samples contain zircons with similar age populations, although relative abundance of each population varies. Zircons of Palaeoproterozic-Archean, Neoproterozoic and Devonian-Early Carboniferous ages are most widespread, whilst zircons of Cambro-Ordovician ages constitute an insignificant portion. Similarly, the Siberian Craton provenance must be rejected as a possible source area for Palaeozoic zircons in the studied samples, as felsic Palaeozoic magmatic rocks are also absent in the Siberian Craton basement. The only known potential provenance area with magmatic rocks comparable in age with the studied Palaeozoic zircon populations are the Altay-Sayan and/or Taimyr - Severnaya Zemlya fold and thrust belts
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Laptev Onshore to Offshore Relation
Authors B.C. Mouly and D. FrankeOur approach consists in 1. constraining the evolution of rifted shelf with the age of magnetic chrons in the Eurasia basin, and interpret a break-up unconformity that correlates in time with the emplacement of the oldest oceanic crust in the Eurasia Basin 2. Differentiate on seismic the sedimentation patterns from greenhouse conditions from those of icehouse conditions, as documented by the ACEX well drilled on Lomonossov Ridge. 3. Correlate nearshore structural cross sections, calibrated on deep wells with shallow water seismic data 4. Compare the basement structure prepared from magnetic records with the acoustic basement interpreted from seismic data 5. Calibrate older seismic data against newer, acquired with long-streamer, to better define the base of the rift infill and its relation to regional structural styles existing from Verkoyansk to Annabar.
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Model of Regional Tectonics and Hydrocarbon Potential Offshore Russia and Foreign Sectors of the Black Sea - Caspian Region
By B.V. SeninAnalysis of new geophysical data on the Black Sea – Caspian Region acquired since late 90-ties, partial reprocessing and reinterpretation of archival geophysical and geological results of oil and gas prospecting both offshore and on adjacent land areas, systematization and generalization of the entire dataset enabled the represented corrections of traditional views upon tectonics and hydrocarbon potential of the Caspian Sea, the Black Sea, the Sea of Azov, and adjacent terrain.
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Regional Seismoprospecting Works in Coastal Territory of Republic Dagestan and in a Shallow Zone Adjoining to it
Authors L.T. Guseinova and R.D. YusufovThe uplift of cretaceous reflecting horizons revealed earlier in a sea direction, has allowed to suggest presence of structures not defined earlier, located in a coastal zone which could be perspective objects for searches of hydrocarbonic raw materials. A neogene – upper cretaceous deposits are perspective here according to prospecting--production drilling. The second regional stage of inspection of southern Foothill Dagestan which has included inspection of a coastal and shoaly zone of the Dagestan part of Caspian sea was finished in 2007-2008. Newly interpreted received results of regional seismic operations, in inspecting the South Dagestan bow area, have allowed to specify a structural and tectonic construction on a neogene- upper cretaceous deposits, to substract in a coastal and shoaly zone 14 new structures perspective for searches of oil and gas and to give them a resource estimation
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Seismic Facies Model of the Lower Cretaceous Eastern Part of the Azov Sea
Authors G.M. Makanova and I.V. ShiryaevaОсновным этапом исследований являлось проведение сейсмофациального анализа. Использование методов сейсмостратиграфии позволило разработать седиментационную модель нижнемеловых отложений неизученной бурением акватории Азовского моря. Полученные результаты использованы для оценки перспектив газоносности выявленных антиклинальных структур.
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New Approach for Building a Tectonic Model of the Black Sea Depression
Authors A.V. Khortov, B.V. Senin, S.D. Kakaranza, N. Kaymakсi, E. Kozhuharov, I. Gabriel, M.I. Leonchik, N.V. Amelin, E.I. Petrov and B.W. HornВ работе представляются результаты новой серии региональных сейсмических профилей, пересекающих всю Черноморскую впадину и отработанных с использованием современных технических средств и технологий спустя 30 лет после проведения здесь первой серии подобных исследований. Полученные материалы позволяют по новому представить ряд аспектов геологического строения, тектоники, истории формирования впадины и её современной геодинамики.
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Reservoir Properties Forecasts in BS10-2+3 Layer Based on Different Geostatistical Inversion Techniques
Authors I.S. Tsybulkina, K.E. Filippova, P.G. Ponomarenko, V.M. Vingalov and S.V. LyagushevВопрос выбора наиболее достоверного метода прогноза коллекторских свойств является весьма сложным и актуальным. Поэтому на примере Северо-Конитлорского месторождения были оценены возможности прогноза коллекторских свойств пласта БС10-2+3 в условиях его значительной латеральной изменчивости и при малых толщинах коллекторов с использованием двух типов геостатистических инверсий, а именно: полнократного куба и частично-кратных сумм.
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AVA Stack Rotation as Fast Track Tool for Seismic Reservoir Characterization - A Case Study from a Pre-Caspian Basin
Authors A. Shestakov and A. JangirovA modified approach of AVA analysis is presented in this paper. It is AVO screening technology which combines AVO analysis and statistical rock physics study for gaining insight into the hydrocarbon reservoir.This workflow is time-efficient and allows for the analysis of large seismic volumes with limited or no well control.
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Biot Inversion of Microseismic Data for Permeability Estimation - A Feasibility Study
Authors R. Shigapov, A. Droujinine and B. KashtanThe estimation of poroelastic properties of reservoir rocks is a very important and topical problem. In this work we focused on the permeability estimation. Assuming that the input data were obtained during hydraulic fracturing experiments, our goal is to estimate the rock permeability using elastic full waveform inversion of microseismic data. We have done a set of numerical tests in order to study stability of the method to noise and velocity model errors.
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CRS Prestack Data Conditioning for Extending AVO Analysis to Low-fold and Low-quality Data Zones
Authors H. Trappe, G. Gierse, J. Pruessmann, G. Harms and H. VosbergThe Common-Reflection-Surface (CRS) method may improve seismic processing beyond imaging, e.g. in an enhanced Amplitude Versus Offset (AVO) analysis. Various applications have shown that the more realistic subsurface assumptions, and the increased fold of the CRS imaging allow to extend AVO analysis into noise zones and to deep targets with low signal quality. Extreme fluctuations of AVO parameters are removed, and AVO anomalies are enhanced. The CRS method assumes subsurface reflector elements with dip and curvature, which implies large-fold stacking surfaces extending both across offset, and across neighboring CMP locations. The extension across neighboring CMPs defines a CRS gather at the central CMP location, comprising data from a multitude of traces. The CRS moveout correction compensates for the local dip across these neighboring CMPs, thus contrasting to conventional AVO super-gathers based on NMO correction that collect dipping events horizontally at varying phase. The presented case studies show that CRS-AVO attribute stacks are produced with a much higher signal-to-noise ratio from CRS gathers than from CMP gathers in conventional AVO. The CRS-AVO attribute sections clearly distinguish anomalies at known or expected gas-bearing reservoirs.
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Prestack Inversion and Probabilistic Lithofluid Classification - A Case Study from the Caspian Sea
Authors S. Klarner, N. Buxton and S. BenkoThe Caspian Sea is currently one of the focus areas for exploration and production in the FSU. Logistically a challenge (large areas with very shallow water) and ecologically sensitive (endemic flora and fauna), it demands operators to develop a sustainable approach to hydrocarbon development in the region. In that context, a better understanding of the subsurface helps to optimize drilling activity as one of the factors having a huge environmental impact. The AVO inversion and probabilistic lithofluid classification approach presented in the current paper, is one of the technologies applied to improve the subsurface understanding of the area in order to optimize the future field development. The workflow includes seismic data improvement by reservoir oriented processing procedures, a comprehensive rock physics analysis on well data, simultaneous inversion of angle stacks, crossplot analysis of inversion results and probabilistic lithofacies classification in the AI-Vp/Vs domain using the established depth dependent rock physics trend. First experience of using a probabilistic approach to quantify the reservoir properties shows that potentially even pore fluids can be estimated from seismic data.
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From Rock Physics Study through Inversion to Seismic Litho/fluid Prediction - A Case Study from Precaspian Basin
By A JangirovIn this paper a new approach is proposed for seismic reservoir characterisation. The workflow shows how rock property trends can be derived, compared with seismic amplitudes and used in prediction of litho/fluid content based on observed seismic amplitudes. The workflow is supported by case study using the data from Precaspian basin.
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Choosing Seismic Dataset with Application of Deterministic Full Stack Inversion
Authors K.E. Filippova, A.A. Kozhenkov, J.L. Debrouх and D.V. IsakovIt is common that several seismic datasets are available on the same project as a result of reprocessing. Different companies may reprocess the same datasets using various technologies and different processing sequence and interpretation team have to choose the most suitable volume for interpretation and reservoir properties forecast. Sometimes it is a really difficult choice.
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Seismic Inversion Potential for Carbonate Reservoir Modeling, as Exemplified by Samara Region
Authors I.A. Babenko, T.V. Nekrasova, V. Sheppard and I. GontarenkoThe paper describes the use of seismic inversion for the purpose of prediction and delineation of oil-saturated reservoir areal Samara region fields.
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SGS-based Stochastic Inversion Workflow for Clastic Thin Layer Properties Recovery in Carbonate Medium
More LessThe problem of recovery clastic layer properties in carbonate medium was solved with Sequential Gaussian Simulation (SGS)-based stochastic inversion. Stability analysis of this workflow results was presented. The estimate of identification possibility low-impedance object in high-impedance medium. Method of assessing sufficient for practice multiple realizations of stochastic inversion was proposed.
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Geology as the Main Factor in Determining the Technology Required in Seismic Inversion and Interpretation
Authors M. Romanenko, D. Kutcheryavenko, S. Iliin, A. Dubok and D. EmeliyanovВ условиях активного развития и применения методик сейсмической инверсии ключом к успешному решению задач прогноза является не столько алгоритм, сколько понимание особенностей геологического строения изучаемых объектов. В рамках работы над одним из производственных проектов мы столкнулись с очень интересным и нестандартным для Западной Сибири геологическим строением изучаемой толщи, которое поставило много нетривиальных задач для акустической и синхронной инверсии. На нескольких примерах с различных этапов проекта показано, каким образом понимание особенностей геологического строения района и целевого интервала может повлиять на методику расчета и интерпретации кубов упругих параметров. В заключении работы даны практические рекомендации, которые могут быть полезны, специалистам работающим в области интерпретации данных сейсморазведки.
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The Detailed Facial Model of Complex Clastic Reservoir Based on Geostatistical Inversion Results
Authors K.E. Filippova, P.G. Ponomarenko, I.S. Tsybulkina, V.M. Vingalov and S.V. LyagushevРассмотрены возможности использования геостатистической сейсмической инверсии для уточнение строения залежи и выделения зон выклинивания и литофациальных изменений продуктивного интервала. Данная методология может быть успешна применена для уточнения строения пластов месторождений Западно-Сибирской нефтегазоносной провинции.
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Electroacoustic Logging and Joule Heating
Authors B. Plyushchenkov and A. NikitinIt is well known that electromagnetic field excites acoustic wave in a porous elastic medium saturated with fluid electrolyte due to electrokinetic conversion effect. Pride's equations describing this process are written in isothermal approximation. Update of these equations, which allows including influence of Joule heating on acoustic waves propagation into account, is proposed here. This update includes terms describing the initiation of additional acoustic waves excited by thermoelastic stresses and the heat conduction equation with right side defined by Joule heating. Results of numerical modelling of several problems of propagation of acoustic waves excited by an electric field source with and without consideration of Joule heating effect in their statements are presented. From these results, it follows that influence of Joule heating should be taken into account at the numerical simulation of electro-acoustic logging and at the interpretation of its log data.
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Deep Fracture Imaging Using Dipole Acoustic Data
Authors A.O. Bolshakov, D.J. Patterson and C. LanCharacterizing acoustic fractures in reservoir rocks is important because these fractures provide critical conduits for hydrocarbon production from the reservoir into the wellbore. The standard method uses shallow borehole imaging services, both acoustic and resistivity, which image the intersection of the fractures at the borehole wall. Cross-dipole technology has extended the depth of evaluation some 2 to 4 ft around the borehole by measuring the fracture-induced azimuthal shear-wave anisotropy. A recently developed shear-wave reflection imaging technique provides a method for fracture characterization in a much larger volume around the borehole with a radial extent of approximately 70 ft. This technique uses a dipole acoustic tool to generate shear waves that radiate away from the borehole and strike a fracture surface. The tool also records the shear reflection from the fracture. The shear-wave reflection, particularly the SH waves polarizing parallel to the fracture surface, is especially sensitive to open fractures, enabling the fractures to be imaged using this dipole-shear reflection data. We use field examples to demonstrate the effectiveness of this shear-wave imaging technology that maps fractures up to 70 ft away and even detects fractures that do not intercept the borehole.
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Inversion of 1D VES Data Using New a Technique Called Recursive Ant Colony Optimization (RACO)
Authors Y. Arora, D.K. Gupta, J.P. Gupta and U.K. SinghIn this abstract a new algorithm is proposed named Recursive Ant Colony Optimization (RACO) for inversion of 1D VES data. RACO is derived from a more general global technique known as Ant Colony Optimization (ACO). In this new algorithm, results obtained from first run (first depth) are fed to next run (next depth) which is called recursion. The level of recursion of the process is defined by the term “depth” and hence directly affects the accuracy of the results. Advantage of using the recursion in this algorithm is that the convergence of the problem becomes exponential which is linear in ACO thus this approach become different from its general form. This code is written in C++ which makes it more time efficient. To make this algorithm stable it is tested on synthetic data of 3 layers earth model and 5 layers earth model. Both of the examples chosen are difficult to delineate due to presence of high resistive layers (K-type and HKH-type curve). Then this method applied to field data from Satkui and Tangasol region of Midnapur district of West Bengal, India. Results obtained after completion of the inversion process are found to be in agreement with the available results.
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The System of Adaptive Well Log Data Interpretation in Geological Modeling
Authors A.N. Petrov, D.A. Kozhevnikov, K.V. Kovalenko and I.S. DeshenenkovWide spread application of 3D geological modeling, oil and gas field development practices resulted in substantiation of the necessity for transition from the traditional concept of “absolute pore volume” to the concept of “effective pore volume”. This could be achieved with the geophysical and logging data algorithms interpretation and procedures system directed to the determination of reservoirs dynamic characteristics with high vertical resolution united with principles of adaptability and petrophysical invariance of reservoirs. Adaptive petrophysical models make possible the quantitative estimation of effective porosity and effective/phase permeability. Formation parameters, which characterize the content of bound water in the matrix and cement, maximum possible total porosity and effective porosity, relations between effective porosity and effective permeability are estimated according to outcomes of petrophysical modeling. Effective porosity is calculated with the standard logs data interpretation. The distribution of reservoir properties in three-dimensional space is carried out with geostatistical simulation techniques. Application of effective porosity to prediction of relative permeability and capillary pressures with log data was realized as an important task for field development design. The test of the proposed technology is conducted on a large number of wells worldwide. Formations consist of clastic fine-grained sandstones with complex cement mineral composition.
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Determination of Capillary Pressures and Relative Permeabilities with Well Logging Data
Authors A. Petrov, D.A. Kozhevnikov, K.V. Kovalenko and I.S. DeshenenkovIn oilfields development process it is necessary to determine attitude of fluidal contacts performedby the deposit area on the base of geological, geophysical and petrophysical data integration add‐in advanced well logging techniques. We propose new capillary model, controlled by a single parameter that is closely related to permeability. Developed model allows more accurate determination of the displaced fluid share at a given capillary pressure during drainage in comparison with analogues. Saturation estimation algorithm based on proposed model was proposed. The advantage of the algorithm is the possibility of hydrocarbon saturation reliable prediction in case of resistivity logging is non-informative due to the low vertical resolution in the layers of low width and anisotropic reservoirs. In practice, Burdine and Brooks-Corey model as the most common approximations of relative permeability curves are used. But these models describe laboratory core measurements data poor in low relative permeability area. New analytical approximations for more detailed and accurate description of relative permeability curves was obtained. Description results show that proposed model has better accuracy in comparison with known analogues. Relative permeabilities can be used for prediction of the brine share in production volume with Leverett function and have great practical importance for field development design.
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Velocity Detection by Duplex Wave Migration
Authors N. Marmalevskyi, S. Gorbachev, Z. Gornyak, G. Dubrova and B. LinkThe sensitivity of the duplex wave migration to the wave propagation velocities is considered. On the field 3D data, the evaluation criteria for detection of correct velocity assignment are shown for the duplex wave migration based on the Kirchhoff integral The opportunities of definition of velocity in thin layers, which thickness is less than length of a seismic wave and complicated with permeable fractures corridors are considered.
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Velocity-less Pre-stack Time Migration in Application to Hard Rock Environments
Authors K. Tertyshnikov, A. Bóna, R. Pevzner and B. GurevichReflection seismic techniques have a number of limitations to get suitable images in hard rock environment. Many seismic migration algorithms need to know the values of propagation velocity of acoustic waves. In sedimentary basins, where layers are usually continuous reflectors, that information could be obtained directly from acquired data, but there are many steeply dips and lack of the horizontal boundaries in hard rock media. In this way, the estimation of velocity model is a really difficult task. Here we describe the velocity-less pre-stack time migration in application to hard rock conditions and demonstrate the results on synthetic data.
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Non-linear Analysis of Low-frequency Microseismic Background
Authors S.B. Turuntaev and O.Y. MelchaevaLow frequency seismic data were analyzed with the help of non-linear Grassberger-Procaccia method. Two data sets were considered: microseismic background inside and outside gas field (“passive” method) and the microseismic background recorded before and after vibrations over an oil field with complicated unknown boundaries (“active” method). It was found, that an application of non-linear methods has to be done with caution. Only the analysis of the records containing pulses allowed to distinct the microseismic background inside the gas field from the background outside the field. The analysis of the records obtained after the vibrator works showed an appearance of deterministic component in the microseismic background after the vibrations at several studied points. Two wells were drilled in proposed points, and the both were successful.
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Incorporation of Multiples for Migration Velocity Analysis with VSP Data
Authors D.A. Nasyrov, D.A. Kiyashchenko, Y.V. Kiselev, B.M. Kashtan and I.V. AbakumovWe demonstrate the original method for the migration velocity analysis with VSP data. The method is based on the use of surface-related multiples jointly with the primary reflected data for the VSP imaging. Velocity updates are carried out by matching the images obtained by using different types of waves. To do it automatically we introduce a cross-correlation type objective function and develop a maximization algorithm based on the adjoint-state method. We show that maximization of the cross-correlation of the images built on different types of waves allows to retrieve the velocity parameters. At the same time the refinement of the velocity model could lead to significant improvements of the seismic images.
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Improved Depth Imaging by CRS Signal Enhancement in Input Shot Gathers
Authors G. Gierse, G. Eisenberg-Klein, H. Trappe, J. Pruessmann and M. ZehnderNoise suppression and signal enhancement prior to prestack depth migration (PreSDM) may significantly increase the resolution of the depth image, and the effectiveness of the PreSDM workflow. The Common-Reflection-Surface (CRS) technique was previously used for this enhancement of seismic prestack data, providing so-called CRS gathers with regularized CMP and offset coverage, and with a strong noise suppression. These CRS gathers considerably improved the depth image in Kirchhoff PreSDM but were not suited for shot-based PreSDM algorithms. This case study now presents a straightforward way to produce geometry-preserving CRS gathers that similarly increase the signal-to-noise ratio. In a first implementation, CRS prestack data interpolation is performed at the existing trace locations providing a straightforward and automatic preservation of the original shot geometry. Application to 3D seismic land data demonstrates the improved signal-to-noise ratio and resolution both in the geometry-preserving CRS shot gathers, and in the corresponding QC stack. As in the Kirchhoff migration of regularized CRS gathers, such enhancements are expected for Reverse Time Migration of CRS shot gathers as well.
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Band-limited Ray-tracing through Rugose Interfaces
Authors C.E. Yarman, X. Cheng, D. Nichols, K. Osypov and M.I. ProtasovStandard ray-tracing is a very efficient way of approximating wave propagation for small wavelengths, or, equivalently, high frequencies. Furthermore, it is still valid when the medium parameters and the wavefields are smooth on the scalelength of the width of the Fresnel volume (Kravtsov and Orlov, 1990). Standard ray-tracing validity conditions break down in the vicinity of an interface when there is high contrast between the two sides of the interface and/or the interface has a complex structure. In this study, we present a new band-limited ray-tracing method that aims to overcome some of the limitations of standard high-frequency ray tracing in complex velocity models that contain complex interfaces. With a modest increase in computational cost, the method presented captures the wave kinematics that are comparable to finite-difference wave propagation with higher fidelity while staying within the ray-tracing framework, without requiring processing or alteration to the original model.
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3D Velocity Model Building Based on Diffractions
Authors S. Dell and D. GajewskiDiffracted events are of great importance in the seismic processing because they allow to identify the presence of small heterogeneities, truncations, faults. However, to reliable interpret such subsurface features caused by diffractions, the letter ones should be properly imaged. An inherent part of the imaging is therefore a migration velocity analysis which should be tuned to diffractions. Moreover, imaging of diffractions is inherently a 3-D problem. In real geological environments one can not expect diffractors to be located below 2-D profiles. The 3-D effects of diffractors located transverse to the profile line leads to a smeared and less reliable diffraction images. We present a method for 3-D velocity analysis based on diffracted events. We perform migration velocity analysis by evaluating the semblance norm along diffraction traveltimes both in the depth and time domain. Finally, we perform Kirchhoff type of poststack migration with estimated velocities to validate the presented velocity analysis.
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Interval Anisotropic Parameter Estimation from Walkaway and 3D VSP Data
By E. BliasThe purpose of this paper is to present a new method for interval VTI anisotropic parameter estimation above and within VSP array. Above receiver array, the method utilizes duplex downgoing multiples (multiples with two reflections: from the boundary and free surface) for estimation of a layered depth velocity model above the borehole receiver array. A three-term NMO approximation function is used to estimate NMO velocity and a non-hyperbolic parameter. Dix-type inversion is applied to the three parameters to invert them to interval Thomsen anisotropic parameters ε, δ above the receivers. Velocity gradient influence is analyzed analytically. It is shown that in many cases we can neglect its influence on anisotropy estimates. Within the VSP receiver array, the method creates a virtual horizontal reflector at each receiver depth by calculating reflected traveltimes as a sum of two first breaks from the symmetrical source points. For 3D or multi-azimuthal walkaway survey, this approach is generalized for a model with horizontal homogeneous orthorhombic layers.
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The Detalization of Difficult Constructed Objects on the Base of Seismic Processing Interpretation
By A.A. NikitinThe article deals with new seismic attributes and processing technologies that provide difficult constructed objects with the forecast of hydrocarbon identification.
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Complexing of the Reflected and Refracted Waves in the Processing and Interpretation of Multichannel Marine Seismic Data
More LessRefracted waves usually removed for processing and interpretation of the marine seismic data. However, they can provide additional information about the structure of the section and the presence of local low velocity zone. In this work the seismic section of the refracted waves along the profile 5-AR (East Siberian Sea) was constructed. With help the refracted and reflected waves was detected the low-velocity anomaly due to hydrocarbon deposit. Made refinement of the structure of the upper part of the lifting of Wrangel. Showed the advantage of using refracted waves for processing of the multichannel marine seismic data. Proposed to use the refracted wave in the processing and interpretation of marine seismic data. Showed the original method of determining the low-velocity anomalies, wich located in the sedimentary rocks.
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Advanced Modern Technologies for Old 3D Seismic Data Reprocessing - Case Study, Kharyaga Field
New seismic processing technologies can help extract additional useful information even if they are used with old seismic data. Seismic acquisition was performed in 2001 with the vibroseis and slanted NonWAZ acquisition system resulting in original bin size of 12.5x25m and nominal fold of 40. New advanced technologies were applied to get get better quality seismic imaging from full data reprocessing sequence. 5D seismic data regularization and interpolation to a denser shot and receiver grid were done to make possible the implementation of WAZ processing sequence. Data was, in fact, mapped to a new perfectly regular survey on bin grid 12.5x12.5m, which had higher fold of 160 and more regular offset and azimuth distribution. WAZ approach made possible COV- processing, azimuthal velocity analysis and 3D Radon using. The main features of our PSDM processing included separate PSDM runs for different azimuth sectors, PSDM from floating datum with shallow velocity derived from refraction statics model and using of non-linear hybrid tomography. Improvements in seismic data resolution, small magnitude faults imaging and correlation with well data are observed as the result of advanced technologies applying.
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Petroleum Systems in the Okhotsk Sea Region
More LessResearch targets are the largest basins of the Okhotsk Sea region (Northern and Western Sakhalin, Northern Okhotsk and Western Kamchatka). The data on composition, petrophysical and geochemical properties of borehole sections’ rocks, seismic survey (CDP technique) were analyzed. Particular attention was paid to the tectonic and sequence stratigraphic subdivision of covers, identifying sediment structure of petroleum systems and relationships between its components: oil source suits, reservoirs and cap rocks. Three groups of petroleum systems were distinguished: Upper Cretaceous, Lower Cenozoic (Pre-Upper-Oligocene) and Upper Cenozoic (Upper Oligocene-Pliocene). The Upper Cretaceous petroleum systems are the top of the folded (mostly destroyed) basement. The Lower Cenozoic petroleum systems are represented by the rift system with complex sediment structure and random pattern distribution of low permeable reservoirs. The Upper Cenozoic petroleum systems pose the highest petroleum potential. This petroleum systems are characterized by asymmetry associated with unilateral progradation of sequences towards deep-sea trenches. Reservoirs prevail in the proximal and central parts of the sequences; siliceous-argillaceous strata with high oil generation potential are predominated in the distal parts of the sequences.
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Making Seismic Data as CSEM Data through the Bäcklund Transform
Authors J.M. Virieux, R. Brossier, S. Garambois, S. Operto and A. RibodettiBäcklund transform is applied to a seismogram in order to construct a new signal where the time is transformed in a pseudo‐time the square of its dimension is expressed in seconds. The Bäcklund transform links partial differential equations related to wave propagation to partial differential equations related to diffusion. Potential applications have been performed previously from magnetotelluric data to pseudo‐seismic signals by using the inverse of the Bäcklund transform. This transform could be applied to the seismic signal through real computations. Therefore, we propose to transform seismic data into pseudo‐CSEM signals for possible applications of these diffusive signals as the initial stage of the full waveform inversion of seismic data.
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Quantitative Analysis of Seismic Uncertainty
Authors K. Osypov, D. Nichols, C.E. Yarman, F. Qiao, M. Woodward, N. Ivanova, Y. Yang, R. Bachrach and Y. LiuUncertainty is inherent in E&P business and understanding uncertainty enables mitigation of E&P risks. Therefore, quantification of uncertainty is essential in decision-making and managing uncertainty generates business value. One of the most critical parameters for reserves uncertainty and well placement is positioning of interpreted geological structure in the depth domain. Even with our best efforts to combine all available data there is still ambiguity in our models, caused by the inherent non-uniqueness of the seismic experiment. The result is uncertainty in the true positions of events in our images. These uncertainties can lead to exploration risk (e.g. trap failure), drilling risk (e.g. dry wells), and volumetric uncertainties. Whilst the underlying ambiguity can never be fully eradicated, a quantified measure of these uncertainties provides deeper understanding of the risks and leads to more informed decision making. We introduced a workflow for the statistical analysis of structural uncertainty associated with the ambiguity of tomographic velocity model building. Our method provides a quantitative way to determine the trap risk. Here we present this seismic-driven uncertainty analysis method and a case study for its application in the Gulf of Mexico.
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Geometric Analysis of Seismic Imaging Operators and Continuation Operators
By A.A. DuchkovIn this paper we provide an overview of some concepts and results by S.V.Goldin in the field of geometric theory of seismic imaging. Then we present some recent results on velocity continuation of seismic images developing his ideas. We will provide a few examples of Hamiltonians describing propagation of singularities during a velocity continuation of seismic (extended) images and propagation of isochrones in the framework of constant-offset migration.
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SVD for Macro-velocity Model Reconstruction by Full-waveform Inversion
Authors I. Silvestrov, D. Neklyudov and V.A. TcheverdaThe key element of seismic processing workflow in areas with complex geology is a depth velocity model building. A full-waveform inversion technique is considered currently both by academia and industry as a potential solution of the problem. The resolution and sensitivity of the method can be studied reliably by considering the Frechet derivative of the original nonlinear forward map. Examining its singular value decomposition provides the detailed information about the inverse problem, particularly about the low-frequency velocity model reconstruction ability. In the current work we present such study considering a look-ahead VSP experiment in which the velocity model below the borehole bottom is inverted. Using truncated SVD we show that success of the inversion strongly depends on the available low frequencies in the data and on the noise level. For the particular model we find the acceptable noise level and the required frequency content of the data needed for reliable inversion of the smooth velocity model. The presented approach may be adapted to any particular model and acquisition system and may be used as a tool for prediction the solution properties prior to any inversion procedure and for producing the requirements to the data which are necessary for successful inversion.
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Reliable Interval Q-factor Estimation from VSP Data
By E. BliasThe purpose of this paper is to present a new method for interval Q-factor estimate using near-offset VSP data. This method is based on objective function minimization of the difference between actual layered Q estimates and those calculated through interval Qs. To calculate interval Qs, we use Q estimates for all receiver pairs that provide reasonable Q values. To estimate layered Q between two receiver levels, we utilize an exponent approach which provides more accurate Q values than the spectral ratio method. Application of this method to real data demonstrates good correspondence between Q estimates and vertical velocity changes.
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Application of Perturbation Theory to TTI Media
Authors A. Stovas, T. Alkhalifah and P. GolikovUsing an elliptical tilted TI medium as a background we apply the perturbation method to compute both the eikonal and the slowness surface equations in a general TTI medium.
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Krauklis Wave - Half a Century After
Authors G. Goloshubin, V. Korneev, B. Kashtan, A. Bakulin, V. Troyan, G. Maximov, L. Molotkov, M. Frehner, S. Shapiro and R. ShigapovHalf a century after the original publication by Pavel Krauklis in 1962, the slow fluid wave in a fracture filled by fluid has got the name of its discoverer. This is the seventh personal name given to an elastic wave and which is now standing in a row with other remarkable scientists: Rayleigh, Love, Lamb, Stoneley, Scholte, Biot. The Krauklis wave is a slow dispersive wave mode that propagates in a fluid layer bounded by elastic media. There are indications that Krauklis wave plays a significant role in a variety of wave propagation phenomena in seismology, acoustics, engineering and hearing physiology. It is distinct by its large amplitudes, high dispersion and confinement to the fractures filled with fluid. In the prospecting seismology Krauklis wave might be an important component of the hydro-fracturing process, seismic wave propagation in fractured reservoirs, and fracture detection.
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Monitoring of Hydraulic Fractures Using Tube Waves in a Well Generated by Krauklis Wave Coming from Fracture Tips
By G.A. MaximovIn previous publications of the authors (Derov&Maximov, 2008, Maximov&al, 2011) the new active method for estimation of hydraulic fracture parameters was grounded. This approach is based on registration of the primary and the secondary tube waves in a well at incidence of external seismic wave on a well with fracture. The primary tube waves are generated when incident seismic wave intersect cross point of fracture and a well. The secondary tube waves are the result of interaction of Krauklis wave with a well. The Krauklis wave propagates along fluid filled fracture and is generated on fracture tips under action of incident seismic wave. The time delay between the primary and the secondary tube waves allows us to estimate the linear size of hydraulic fracture. The key question of this approach is amplitude of the secondary tube waves to detect them among other arrivals and noise. The developed mathematical model and numerical calculations represented in the report show that amplitudes of the secondary tube waves have the same order as amplitudes of the primary tube waves and hence they can be detected by VSP technique for both cases of subhorizontal and vertical hydraulic fractures for general 3D statement of the problem.
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A Frequency Dependent Ray Tracing for a Non-flat Boundary
Authors M. Protasov and K. OsypovThis paper presents an approach to ray propagation through a non flat boundaries. There is a fundamental problem in a ray based theory application in complex model that particularly contains complex boundaries. In many cases ray based theory breaks down (for example when boundary is rough with respect to wavelength) while physically there is wave propagation and it means actually there is ray propagation. But these rays are not high frequency rays actually these rays depends on frequency. The presented approach gives the way to compute frequency dependent rays within the ray propagation through boundaries. It is based on usage of boundary integrals. Outside the boundary it is a conventional ray tracing. The approach is applicable for ray based imaging and ray based tomography.
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Footprint of the Fine Structure of the Reservoir in Scattered Waves
Authors V. Cheverda, V. Khaidukov, V. Lisitsa, G. Reshetova, V. Pozdnyakov and V. ShilikovIn order to simulate interaction of seismic waves with cavernous/fractured reservoirs the finite-difference technique based on locally refined in time and space grids is used. The need to use these grids is due to essentially different scales of heterogeneities in the reference medium and in the reservoir. Parallel computations are organized on the base of 3D Domain Decomposition into elementary subdomains in the both reference medium (coarse grid) and reservoir (fine grid). Each elementary subdomain is assigned to its specific Processor Unit forming two groups – for reference medium and for reservoir. The data exchange between PU within the same group is performed in a standard manner – by nonblocking iSend/iReceive commands. The data exchange between two groups is done simultaneously with coupling of coarse and fine grids and is controlled by specially designated master PU. Results of numerical simulation for a realistic model of the carbonate reservoir are presented and discussed. On the base of numerical simulation an approach to recovery of orientation of fracture corridors is proposed and verified by comparison with direct observation of fractures within a well.
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Methodology for Evaluation of Fluid Saturation of Fractured Reservoirs on the Base of 3D Simulation of Seismic Waves
A detailed study of fractured reservoirs requires the use of all types of wave fields, as each of them displays its different properties the reflected waves are responsible for its correct positioning in space, while scattering ones bring information about its internal fine structure. Therefore, full description of the reservoir need an adaptive procedure for the construction of seismic wave images of different scales. It should be able to image not regular interfaces only, but microheterogeneities like caverns, cracks and fractures as well. In the paper we discuss some new approaches to scattered waves imaging on the base of accurate finite-difference simulation.
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Feasibility of Cross-well Hydrofracture Monitor by Accurate Numerical Simulation of Seismic Waves Propagation through Mu
Authors V.V. Lisitsa, C. Economides, G.V. Reshetova and V.A. TcheverdaIn this paper we present full scale numerical simulation of cross-well observations for shale gas exploration. The main technology used in production is based on hydro fracturing, however it is reported as a rule only about 20% of fluid used for fracturing gets back. Thus some fluid remains in the fractures blocking them from gas penetration. On the base of the full scale numerical simulation the principal ability to use time-lapse 3C cross-well observations in order to recover extremely fine variations of the background, including movement of watering zone was shown. Moreover strong diffraction was observed from the gas-water contact which allows to exploit intensively developed approaches of diffracted/scattered waves elimination and imaging to recognize the movement of the contact.
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Efficient Finite-difference Algorithm for Simulation of Seismic Waves in Models with Anisotropic Formations
Authors D.M. Vishnevsky, V.V. Lisitsa and V.A. TcheverdaAnisotropy is wide-spread in the Earth’s interior; however anisotropic formations typically comprise relatively small part of the models. It means that use of computationally expensive numerical algorithms for full anisotropy inside whole computational domain is rather inefficient. So, we present an original advanced finite-difference algorithm based on the domain decomposition technique with individual scheme, used inside subdomains. It means that in the main part of the model which is isotropic or VTI, a standard staggered grid scheme (SSGS) is utilized while the Lebedev anisotropy-oriented scheme is used inside domains with anisotropic formations. On the one hand this approach is as efficient and computationally cheap as SSGS. On the other hand it allows simulation of seismic wave propagation in arbitrary anisotropic formations.
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Layer-stripping with Offset Variable Parameters Compensating for the Reflected PS-waves Splitting in an Azimuthally Anisotropic Layer
Authors W.V. Karsten, E.V. Afonina and S.B. GorshkalevLayer-stripping algorithm with the offset variable parameters is applied to the synthetic data for the model with two different anisotropic layers. Layer-stripping with offset variable parameters and with constant parameters are compared. Variable parameters make it possible to compensate for the PSwave splitting in the upper anisotropic layer more correctly. Removing the influence of the upper anisotropic layer permits investigation the anisotropy of the lower layer
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New Prospects Discovery by Geological Support of Development Drilling
Authors A.G. Dubok, T.S. Zhuzhel, S.A. Potapenko and R.S. SharipovIn the current paper a successful example of solving a goal which took place over development drill support process is presented. The work was carried out using 3D seismic data reinterpretation (seismic facies analysis) and by operative involving of 8 drilled wells information into the model. Onshore oilfield X is located in Western Siberian region, productive formation is related to Upper Jurassic sistem and characterized by numerous uncertainties, including wide tuning zone, reservoir properties distribution. Data integration and effective drill support process allows to reduce uncertainty in J1 fm area of distribution, discover new perspective area to the following drilling. Additional oil reserves and high permeability of the formation are greatly increased drilling profitability.
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Correlation of Stratigraphic and Structural Framework of Begal Basin
Authors M. Jain and M. RastogiProlific hydrocarbon accumulations in eastern part of Bangladesh indicate the presence of active petroleum systems in the Bengal basin. Petroleum system analysis of the Bengal basin using available sand–shale percentage and organic carbon content, rock-eval pyrolysis and geological data help us to determine the probable Kitchen areas. Bakhrabad Gas Field being a well known gas field in the basin area, has been chosen for applying current methodology and then apply the same technique to an unknown Sariakandi-Madarganj area in the shelf-slope area. Detailed structural and seismo-stratigraphy of the Bengal basin have been established. Regional depth contour maps of different seismo-stratigraphic horizons of Madarganj-Sariakandi and Bakhrabad areas have been prepared to determine the sedimentary structures and spatial distribution of the stratigraphic units. In areas where there were no wells pseudo wells have been generated from those depth contour maps for the purpose of determining the kitchen areas. The analysis revealed presence of type I, II, and III kerogens. Petroleum systems analysis of Basin area (Greater Bakhrabad) and Shelf area (Madarganj-Sariakandi) areas revealed hydrocarbon generation, expulsion and potential of the Bengal basin and this may lead to new discoveries in future.
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Application of Electroprospecting Methods for the Prediction of Oil and Gas
By D. PopovThe paper is devoted to the experience of joint use of such methods as Transient Electromagnetic soundings (TEM) and Differential Normalized Method of Electrical prospecting (DNME) in the Siberian platform. Profiles and maps of geoelectric parameters were obtained. Well data were used to determine the electrical resistance typical for a hydrocarbon reservoir. According to the results of DNME identified areas with anomalous polarization coefficient, which in some conditions can be due to hydrocarbon accumulations. Based on these methods the forecasting of oil and gas locations have been done. The high convergence of results from different methods is observed. Keywords: electroprospecting methods, Transient Electromagnetic soundings, Differential Normalized Method of Electrical prospecting, electrical resistance, induced polarization, Siberian platform, search for oil and gas deposits.
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Geochemical Source Rocks Evaluation and Hydrocarbons Studies in North of Dezful Embayment
Authors M. Daryabandeh and F. TezhehIn the context of this evaluation, the most relevant ones are the Lower Cretaceous Garau, and Middle to Upper Cretaceous Kazhdumi and Gurpi Formations and the Tertiary Pabdeh. The potential source rocks investigated include the Pabdeh, Kazhdumi and Garau Formations. These three formations, which are important source rocks in the basin and have been discussed extensively in the literature, were used as a laboratory standard in this study. The crude oils examined in this study were obtained from reservoir formations of various ages from throughout the area. The source rock screening analysis indicates that the Garau and Kazhdumi especially from the Northwestern part of the area, and Pabdeh in the southeastern part have substantial oil-generation potential. The Gurpi is not a source rock, although has mostly black shales. Selected source rock and oil samples were characterized in more detail, and the distributions and concentrations (both relative and absolute concentrations) of biomarkers in different source rocks and oils were determined. The biomarker characteristics were combined with other geochemical and geological data to interpret the sources, depositional environments, lithology and maturity. Oil–source rock correlations were made between source rocks and a number of crude oils based on quantitative and qualitative biomarker distributions.
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Stratification of the Upper-Jurassic Sediments Based on 3D-seismic Survey (Middle Near-Ob' Region)
Authors S.V. Lyagushov and I.A. PeshkovaLayering of the Achimov sediments based on 3D seismic survey data to trace the top and the bottom of the Achimov sediments, to establish a strong correlation between seismic characteristics and log data, and, as a result, to develop seismogeological base for geologic modeling. Efficient use of seismic inversion for layering structurally complex Achimov sediments and solid forecast of their reservoir properties
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Inversion History of the Southern Area of the Llanos Basin, Colombia
Authors A. Escalona and C. Moreno-LopezThe Llanos basin is the most prospective basin for hydrocarbons in Colombia. Usually the main hydrocarbon system is related with the foreland basin phase developed during the Tertiary. However, recent discoveries in the southern Llanos basin associated with inversion of Paleozoic structures forming gentle anticline structures in the Cenozoic interval indicates a new trend in exploration. This study uses seismic and well data, in addition to previous work in the area, to describe the tectono-stratigraphic evolution in order to understand the different styles and timing of deformation and how the Paleozoic inverted structures control the petroleum system.
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Regularities of Lithofacial Variation of Productive Series Sediments of South Caspian Basin
More LessIn the last hydrocarbon exploration has intensified in the offshore part of the South-Caspian Basin (SCB). New data allowed detailing regional distribution of reservoir beds and facies change of the Productive Series. Regional patterns of change in reservoir and lithofacial properties of the Productive Series (PS) deposits of SCB have been studied on over 1000 rock samples from 40 wells, as well as on 25 thin sections. Determination of lithological and reservoir properties of rocks allowed drawing a series of maps reflecting regional variation of the parameters. In addition, 5 lithofacial zones encompassing the upper and lower divisions of the PS (except for the Baku Archipelago). Facies of the PS lower division have been found to differ from those of the upper division in that south-westerly silty-clayey fraction exhibits substantial increase and carbonate content of rocks increases slightly.
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The Influence of the Bazhenov Structure on the Reservoirs Formation on Kalchinskaya Area
Authors R.R. Khalimova, L.V. Chernovets and I.A. RafikovThe Bazhenov suite sediments are one of the prospects and at the same time unique in the architecture on the Uvat area. Bazhenov suite is one of the main source rocks, seal for overlying layers, and also is independent oil reservoir at that part of area where it has anomalous structure. Complicated tectonic structure is one of the possible migration paths for overlying Neocomian sediments and perhaps it is the cause of insignificant presence of hydrocarbonate in the underlying Jurassic sediments. In this paper we present complex logging analysis, sedimentological core analysis, seismic facies analysis and dynamic 3D seismic data analysis and acoustic inversion interpretation results
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Sequence Stratigraphy as a Tool for Geological Interpretation of Seismic Data - Case Studies
Authors E.O. Malysheva, V.V. Bykov, D.A. Daudina, M.L. Evdokimov and T.F. SokolovaSequence stratigraphy was introduced and applied to geological studies as a tool for prediction of reservoirs, seals and source rocks. It integrates regional geological, well and seismic data. Current paper presents the results of case studies in different sedimentary basins of Russia. Sequence stratigraphy was applied to the fields and areas with different structural and depositional paleoenvironments. It proved to be most effective in the The Western Sybirian clinoform neokomsky formation (K1). The approach, used to identification of sequence boundaries, maximum flooding and transgressive surfaces, was based both on seismic and well data. The most favourable location of reservoirs was predicted in fan and channel complexes of lowstand sequence tract and shelf bar complexes of highstand sequence tract.
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Geological Model of Deepwater Turbidities of Tuapse Trough Based on Seismic Attributes, Spectral Decomposition and RGB
Authors O.A. Almendinger, A.V. Mituykov and M.M. PopovRecent advances in deep water drilling technology have opened new domains for hydrocarbon exploration. And now they have became one of the main targets for drilling. Nevertheless because of the high costs when operating offshore in deep water, requires an integrated approach. This study is an example of detailed approach taken to the characterization and interpretation of deepwater fans of Tuapse Trough in Black Sea. Use of variety of 3D standart seismic attributes, spectral decomposition and RGB blending has considerably advanced the geological model of fan complexes.
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New Approaches to Geological and Hydrodynamical Modelling of Fractured Reservoirs in East Siberia on the Base of Complex
Authors V. Kharakhinov, S. Shlenkin, V. Zereninov, O. Koulishkina and A. MasjukovWe propose a technology for geological and hydrodynamic modelling of fractured carbonate reservoirs. The technology is based on integrated interpretation of 3D seismic reflected and scattered fields and the borehole information.
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The Prediction of Oil-gas Perspective Reservoirs in Terrigenous Vendian and Lower Cambrian Deposits of East Siberian
Authors V.I. Mitasov, I.A. Kushmar and V.A. KondratevПрогноз залежей нефти и газа в продуктивных терригенных отложениях Восточной Сибири по данным сейсморазведки представляет собой весьма сложную задачу, что обусловлено отсутствием структурного контроля этих залежей. Поэтому различие между коллектором и неколлектором должно быть зафиксировано по характеру изменения динамических атрибутов сейсмического волнового поля. Подобная процедура осуществляется уже на этапе первичной обработки полевых сейсмических материалов с сохранением динамики сейсмического волнового поля. Это значительно улучшает выразительность сейсмического волнового поля и повышает соотношение «полезный сигнал»/«помеха» практически на порядок а сейсмические горизонты в интервале А-Ф прослеживаются по латерали в виде четких когерентных отражений. Расчет теоретических значений плотности на основе использования параметров петрофизической модели, позволяет определить геоакустические свойства изучаемой среды, что обеспечивает установление устойчивых коррелятивов между атрибутами сейсмического волнового поля и коллекторскими свойствами горных пород через их акустические жесткости. Анализ динамических атрибутов сейсмического сигнала позволил выделить наиболее информативные из них, позволяющих зафиксировать различие в волновой картине между «сухими» и «приточными» скважинами, расположенными на одном профиле. В результате двумерного сейсмоакустического моделирования было оптимизировано число атрибутов, которые имеет смысл использовать для установления их количественных взаимосвязей с коллекторскими свойствами. Установлено, что наиболее информативными атрибутами явились те, в формирование которых существенный вклад привнесла амплитудная составляющая. Приводятся практические примеры прогноза нефтегазоперспективных оюъектов в сложных геологических условиях Восточной Сибири.
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Structural and Sedimentological Criteria for Traps Prediction in Miocene Deposits, Abin-Ukrainian Field
Authors P.A. Zemtsov, V.S. Derduga, A.V. Derduga and S.V. KuksovResearch area is located within southern flank of the West Kuban Trough. The final stages of the trough forming are connected with both the intensive growth of Caucasia orogen and the thick molasses filling. This has led to the post and synsediment tectonic processes and, as consequence, all this has been the reason of forming of the oil-fields with the specific geological complexity which are greatly differ from the HC traps in a platform conditions. Most of the fields in this area are mature. However structural analysis and sedimentological researches have been conducted quite rare and, commonly, in the initial exploration stage. As a result these parts of the structures, which were not enough studied by the drilling, are remained disputed. This has predetermined a need of the wells and seismic data review on the basis of modern techniques of of geological interpretation.
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Degree of the Level of Scrutiny and the Basic Directions of Prospecting Works in the Northern Part of the East Kamchatka Deflection
Authors N.A. Kulakovskiy and M.A. GrigoryevИзложены перспективы нефтегазоносности северной части Восточно–Камчатского прогиба
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3D Joint Inversion of Marine Magnetotelluric and Controlled-source Electromagnetic Data
Authors A.V. Gribenko, M.S. Zhdanov and G.A. WilsonMagnetotelluric (MT) data naturally manifests itself as noise in marine controlled-source electromagnetic (CSEM) data. It follows that MT data can be extracted from measured CSEM data for the relatively negligible cost of additional data processing. MT data has a lower yet broader frequency content relative to the higher and narrower frequency content of CSEM data. Moreover, MT and CSEM methods are sensitive to different geological structures. With the availability of complimentary data sets, we present a new approach to the 3D joint inversion of both CSEM and MT data. Our method is based on the 3D integral equation method for modeling, and focusing regularized inversion. Our examples of a hydrocarbon-bearing reservoir adjacent to a salt dome show that joint CSEM and MT inversion has better model resolution compared to CSEM or MT inversion alone.
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3D CSEM for Hydrocarbon Exploration in the Barents Sea
Authors D.V. Shantsev, P.T. Gabrielsen and S. FanavollLarge multi-client 3D CSEM surveys have been acquired in the Barents Sea in 2008 and 2010. This data has been used by oil companies in Norwegian license application rounds to support their geological models and prospects. We show case examples where 3D resistivity models obtained by inverting CSEM data help locate areas of interest and update prospect risks. Despite the challenges often associated with the Barents Sea, such as a complex overburden and large resistivity anisotropy, the producing Snøhvit Field is imaged as a CSEM anomaly with the correct burial depth and lateral extension. This shows that CSEM data can be an important exploration tool in the Barents Sea.
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Advances in Multigrid Solution of 3D Forward MCSEM Problems
More LessIn this note we concentrate on iterative solution of the linear algebraic systems resulting from the finite-difference discretization of 3D forward mCSEM simulation. We review and test a recently developed multigrid preconditioner to an iterative solver and introduce some changes into the smoothing scheme of the multigrid algorithm. We substitute the originally used symmetric multiplicative Schwarz smoothing scheme with that of additive Schwarz. We also found an approximately optimal value for the scaling factor needed for additive Schwarz smoothing. Our changes result in a faster and naturally parallelizable algorithm.
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Effective Calculation of EM Green’s Functions Applied to MCSEM Forward Modelling
More LessIn this paper, we present an algorithm for calculating Green’s functions and EM fields for a dipole transmitting source embedded in a layered homogeneous earth. We first set up a fictitious interface through the source parallel to layer boundaries. The EM potentials are continued upward and downward from the interface with continuity conditions, where the reflection coefficients are derived from the accumulated impedances or conductances. The source coupling is treated as a jump of boundary conditions at the fictitious interface. In this way, the source term in the mathematical formulation is separated from the propagation terms. This generalizes the algorithm for any form of electrical and magnetic transmitting dipole sources and simplifies the mathematical formulation and programming. We demonstrate the effectiveness of the technique by considering a horizontal electrical dipole as transmitter for marine CSEM forward modeling.
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Spectral Induced Polarization Measurements of Hydrocarbon-bearing Rocks and Fluids
Authors V. Burtman, M. Endo, T. Ingeman-Nielsen and M.S. ZhdanovAs part of our research into spectral induced polarization (IP) methods, we have measured the complex resistivity (CR) spectra of hydrocarbon-bearing rock and fluid samples from 0.1 Hz to 1 MHz using laboratory CR and dielectric spectroscopy equipment. Our rock-fluid samples included artificial and sandstone reservoir rocks saturated with synthetic oil, tap water, and distilled water. Our fluid samples included oil-based mud, tap water, and distilled water. Statistical analysis of our measurements conclude that hydrocarbon-bearing rock and fluid samples contain significant SIP responses; the mechanisms of which are only partially understood at present. Additional research is needed to clarify the different IP mechanisms in different frequency regimes, but we can conclude that it will be necessary to account for SIP effects when interpreting electromagnetic (EM) data for hydrocarbon exploration and formation evaluation.
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Study of the Inductively Induced Polarization of the Near-surface in Eastern Siberia by TEM Sounding
Authors S.V. Kompaniets, N.O. Kozhevnikov and E.Y. AntonovIn Eastern Siberia, the TEM sounding method has found wide use in studies of sedimentary basins, search and prospecting of oil and gas fields and ore deposits, and solving other geological problems. As a rule, TEM data are interpreted in the context of conductive non-polarizable geological media. In most cases it is a reasonable practice, but TEM data measured in some regions couldn’t be interpreted without regard for the inductively induced electrical polarization. The inversion of the TEM data in terms of 1D conductive polarizable earth model has shown that induced polarization effects are due to near-surface layers rather than to the deep ones. It some cases taking into consideration induced polarization effects provides insight into the nature of geological objects under study.
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Geostatistical Estimation of Different Interpolation Techniques
Authors Е.V. Kovalevskiy JSC and М.V. Perepechkin JSCВыполняется сравнение различных методов детерминированной и стохастической интерполяции скважинных данных. Показано, что воспроизвести в объеме среды и гистограмму, и вариограмму исходных скважинных данных очень непросто
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A Pre-processing Workflow for Multi-point Statistics Modelling Involving Training Image Construction and Well Validation
Authors P.J. Ruelland, C. Ronot, E. Wirbel, F.J. Laugier and P. Biverwells is enabled by “printing” into the simulation grid an appropriate 3D pattern of connected facies extracted from the 3D training image, after a full scan of the training image has been performed. Multiple-point simulation can be run using either stationary or non-stationary training images.
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Determination of Geological Heterogeneities Producing Formations on the Basis of Spatial-temporal Interpolation
By I.I. EfremovIdentified shortcomings of digital 3D geological models of oil and gas in its adaptation to the development history. Shown that the results of a study of deviations of actual rates of development for the project data often have very valuable information, particularly about the structure of the fractured reservoirs, the presence of channel filtering on areas previously undetected areas of destruction. The presented method based on the process of spatial-temporal interpolation of data obtained from the monthly performance report. Using techniques to determine the geological previously unidentified heterogeneity, hydrodynamically correctly adapt the original model to the geological features of the real field.
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Simulation of Fault-related Small Scale Convection
By D.D. DoganIt is well known that temperature distributions of geothermal areas are strongly affected by the local fluid circulations. Particularly, fault zones with high permeabilities can trigger fluid circulation depending on their permeability contrast on the surrounding medium and on their spatial extension. In this study, evolution of time-dependent, fault related hydrothermal circulation and resulted temperature distribution were investigated. Various fault geometries and depth extensions were used to simulate the small scale convection pattern related to the fractures. In the models, dramatic increase in heat flux was observed with the increasing number of fault zones.
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The Issues of Resources Provision and Methods of Solving this Question of the Layer O4, Tolkaevsko-Sorochinsk Dome, Sorochinsko-Nikolskoe Field, Orenburg Region
Authors N.N. Myakinina and E.S. LopatinaСуществует проблема несоответствия ресурсной базы месторождений и данных по добыче нефти, связанная с возможным недоучетом начальных геологических запасов. Одним из них является Сорочинско-Никольское месторождение. Уникальным объектом здесь представляется пласт О4, который содержит карбонатные коллекторы. Так на Толкаевско-Сорочинском куполе на 2010 год по этому пласту обеспеченность запасами углеводородов составляла 1 год, при достаточно высокой и стабильной среднегодовой добыче и низкой обводненности продукции. Рассмотрение корреляции пластов, анализ обоснования принятых ВНК, определение условий формирования, характеристики коллекторов на основе диагенеза карбонатной толщи окского надгоризонта, переинтерпретация данных сейсморазведки 3Д, атрибутный анализ, уточнение петрофизических параметров привело к построению новой геологической модели. В результате на примере группы пластов О4, О4а/, О4а и О4б окского надгоризонта Толкаевско-Сорочинского и Бородиновского куполов Сорочинско-Никольского месторождения выделен единый работающий резервуар, произведено укрупнение геологических объектов и, как результат, установлена причина несоответствия извлекаемых запасов и добычи углеводородов и предложен метод решения
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Application of a Digital Workflow to Integrate Geosteering and Field Development Planning
Authors A. Kharitonov, J. Pitcher, E. Bikchandaev, A.A. Alabushuin and Y.V. YuvzhikOne of the challenges of modern oilfield development is integrating data acquired while drilling horizontal development wells into a geological framework. As part of an ongoing development program in the Kyrtael field, Komi Republic, a new integrated geosteering platform was introduced to assist in well placement and field development. The platform linked a structural model of the field to a real-time geosteering application, to allow rapid transfer of interpreted data between the real time well construction environment and the geological interpretive environment An example of the value of such a platform was demonstrated on a recent well. A previously unknown geological discontinuity was encountered in a well that was being actively geosteered. Although several geological interpretations of the discontinuity exist, the size and position are mapped in the existing wellbore and when transferred to the interpretive environment, consideration of that feature can be made during the planning process for two further upcoming wells. Understanding that the feature exists and its potential impact on upcoming wells adds significant value to the understanding and process of developing well plans. By integrating all of the data in a common environment enables rapid appraisal of new data and its impact on future development plan.
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Reservoir Permeability and Horizontal Well Drainage Volume Identification on the Initial Stage of Field Development
By A. SemenovИспользование горизонтальных скважин стало стандартной практикой при разработке ряда месторождений. Ряд математических моделей, предложенных Joshi S.D. (1991) и Butler R.M. (1994), используется для математического описания работы горизонтального ствола. В настоящее время под математическим моделированием понимают чаще всего моделирование резервуара и скважины в гидродинамическом симуляторе. Однако данное описание системы скважина-пласт с одной стороны является слишком простым для описания реальной природы в силу дискретности и ряда модельных предположений, с другой стороны – слишком сложным для принятия ряда повседневных решений инженера по разработке резервуара. Целью данной работы являлась разработка и применение на практике аналитических инструментов для математического моделирования горизонтальной скважины. Приток к горизонтальной скважине отличается от притока к вертикальной скважине не стационарностью, необходимостью обладания более полной информации о коллекторе при прогнозировании. Не стационарность можно представить как зависимость коэффициента продуктивности скважины от времени (материальный баланс для замкнутой зоны дренирования). Как показал Semenov A.A. (2010, 2011), формализованное сравнение модельных кривых зависимости продуктивности от времени с данными реальных замеров со скважин позволяют определить зону дренирования горизонтальной скважины и получить уточненное распределение ФЕС (фильтрационно-емкостные свойства) пласта. Что дает возможность оценить дренируемые запасы залежи, и оптимизировать плотность сетки скважин в зонах с наилучшими свойствами. Решение данных задач показано на примере залежи пластов Як3-7 Ванкорского месторождения.
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An Experimental Study of Aphron Based Drilling Fluids
Authors S. Gokavarapu, S. Gantla, J. Patel, D. Shah and N. NatrejaIn order to drill depleted reservoir, high permeability formations, and other under pressure zones we require drilling fluids which are having density lesser than that of water. Thus, various methods have been developed by injecting air or inert gases in the drilling fluids in order to reduce the equivalent density of the drilling fluids. In order to solve the problem Aphron based drilling fluids are used for drilling to eliminate the problem associated with the above mentioned reservoirs. A laboratory study was initiated to determine the physical and rheological properties of Aphron based drilling fluids for successful completion of wells and its cost depends to a considerable extent on the properties of the drilling fluids. There is no need of injecting air or gases because Aphrons are produced easily at the surface with mixing equipment. This paper gives the detail description of composition and properties of oil based and water based Aphron drilling fluid systems. At last, the potential application of Aphron Based Drilling Fluid Technology in Indian Scenario has been highlighted
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Improved Oil Recovery of High-viscosity Oil Pools by Combined Steam Injection and Physicochemical Stimulation
Authors L.K. Altunina, V.A. Kuvshinov, S.O. Ursegov and M.V. ChertenkovPresented are the results of laboratory research and field tests of physicochemical technologies intended to improve oil recovery of high-viscosity oil pools developed by steam injection (SI). To increase SI efficiency we proposed to combine it with physicochemical methods using gel-forming systems to increase reservoir coverage and oil-displacing systems to provide additional oil displacement. Two IOR technologies have been developed with thermotropic gel-forming polymer and inorganic systems, which under surface conditions are low-viscosity aqueous solutions, whereas under reservoir conditions they are converted into gels. Gelation time ranges from some minutes to several days at 30-320оС. In 2002-2006 pilot tests were carried out in Russia and China. Since 2007 technologies are commercially used, 124 wells were treated, additional oil production amounted to 340 thou tons. We developed technology alternating SI and physicochemical stimulation with oil-displacing systems based on surfactants, generating СО2 and alkaline buffer solution in situ. Pilot tests were carried out in Russia and China. At steam flooding water cut decreased by 10-20%, oil production rate increased by 40%. At cyclic steam stimulation oil production increased 1.8-2.3 times and prolonged for 3-5 months, oil viscosity decreased 3 times. The systems are commercially produced in Russia and China.
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Field Development and EOR
More LessToday, one of the most effective methods to increase oil recovery and stabilization and reduction water cut in the wells is a measure for the construction of lateral wellbores. The purpose of the course work is to analyze the operation of wells and sidetracks to prove the effectiveness of this technology in the oil and gas fields.
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Reflection of No Equilibrium Two Phase Processes of Filtration in Heterogeneous Media in the Active Seism Acoustic Borehole Monitoring Data
Authors O.A. Hachay, V.V. Dryagin, G.V. Igolkina and O.Y. KhachayПроизводится сопоставление неравновесных эффектов при независимом гидродинамическом и сейсмоакустическом воздействии на нефтяной пласт. Известно, что при дренаже и пропитке проявляется эффект гистерезиса на кривых относительной фазовой проницаемости в зависимости от водонасыщенности пористой среды при нескольких циклах воздействия: дренаж-пропитка-дренаж. В предыдущих работах произведен анализ данных сейсмоакустического мониторинга в режимах фонового излучения, отклика на первое воздействие заданной частоты и на второе воздействие. Для анализа сейсмоакустического отклика во времени на фиксированных интервалах по скважине предложен алгоритм построения фазовых диаграмм состояния многофазной среды. В настоящей работе на основе имеющегося алгоритма добавлен алгоритм анализа изменения пространственного, но интегрального по времени за одинаковые периоды наблюдения методом фазовых диаграмм состояния многофазной среды в пределах нефтяного пласта.
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First Deep Horisontal Boreholes Drilling and Pumping for Oil Extraction at the Urubcheno-Tohomskoe Oil-gas Condensate
Authors A.G. Vakhromeev, R.U. Siraev, V.M. Ivanishin and R.K. AkchurinProblems of deep pumping oil horizontal borehole drilling and postcompletional flow testing in basal carbonate crevice oil complex at the biggest in eastern siberia urubcheno-tohomskoe oil-gas-condensate pool are discussion. Key words: horizontal borehole drilling, geology and technology conditions, oil reservoir (deposit)
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A New Chemical Additive for Preventing Shale and Marl Layers from Swelling During Well Operation
More LessThe collapse of shale and marl layers is a significant challenge in drilling oil and gas wells.The suitable fluid must have tailor-made rheological properties to assist it in dissolving and dispersing clay minerals especially Illite, Montmorilonite, Chlorite, and Kaolinite. Production of this kind of fluid demands in depth geological and drilling studies on shaly-marly formations. Various drilling fluid chemical additives including glycol, which is customarily used in South oil regions of Iran, were investigated and drilling problems in marl and shale layers are discussed. In the following sections an account of seven wells from the Marun field encountering stuck pipe is given. Details of these cases such as depth of stuck pipe, pipe releasing approach and new types of utilized fluids are also presented. Experiments were conducted with a tablet-making metal apparatus to study the effectiveness of proposed substances on dispersion of shale and marl formations and overcoming the stuck pipe problem in the Petroleum laboratory.
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Estimation of Gas Hydrate Saturation from Sonic Log Data in the Krishna Godavari Basin, India
Authors D. Bhowmick, D.K. Gupta, U. Shankar and K. SainThis paper is based on the determination of gas hydrate and free saturations in the Krishna Godavari Basin of India using two different rock physics modelling approaches. The rock physics models are used to generate the initial models for the inversion procedure and the sonic log data is provided as its input. We have also introduced a new and fast hybrid inversion technique formed from the combination of sequential inversion and Multivariate Newton Raphson method. The results obtained from both the models are compared. It is found that both the models show variations in results. The three phase weighted method estimates about 10-12% gas hydrate and 0.5-0.7% free gas in the region. On the other hand, the saturations of gas hydrate and free gas obtained from effective medium model are found to be 16-20% and 1.0-1.2% respectively. The results obtained from the later model are found to be in good agreement with the previous results.
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Estimation of Gas Hydrate Saturation Using Rock Physics Modelling - A Case Study in the Krishna-Godavari Region
Authors D. Bhowmick, D.K. Gupta and U. ShankarThe NGHP Expedition 01 confirmed the presence of gas hydrate in the Krishna Godavari basin region. We have used the LWD sonic log of the NGHP-01-05 site obtained during this expedition and determined the hydrate reservoir properties using two different rock physics modelling approaches. We applied the ant colony global optimization technique to invert the acoustic properties into reservoir properties. The initial models used during the inversion were generated using rock physics equations. The region lying above the BSR was subjected to determination of gas hydrate saturation while the one below BSR was analyzed for free gas. The saturations of hydrate and free gas and also the porosity of the sediments were mapped for the NHGP-01-05 well. It was found that the sediments at the site are saturated with about 12-20% gas hydrate and 0.5-1.5% free gas.
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Kinematic and Dynamic Characteristics of Seismic Pulses in Porous-fractured Rocks with Effective Spatial Wave Dispersion
Authors S.M. Glubokovskikh and V.E. RokThis work concerns with seismic pulses propagation in porous-fractured rocks. Such geological media could possess strong macroscopic spatial dispersion of seismic waves. Results of physical modelling are compared with theoretical estimations of group velocities based on linear slip model of fluid-saturated fracture. They are in good agreement. Computer 3D full waveform simulation of compressional pulses reflection on the boundary of isotropic and transverse isotropic media with horizontal symmetry axis provide a validation that use of group velocities instead of phase ones raises accuracy of the Rueger's approximate equations when concerning utilized in practice seismic signals.
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Rock Physics Modelling for Successful Well-log Interpretation
Authors L.A. Uspenskaya, D.V. Emelyanov, A.P. Kulik, D.A. Garenskih and A.A. BelomestnykhEvaluation of influence of fluid saturation and lithological composition on elastic properties becomes one of the most relevant objective today. For a solution of such problems using a petroelastic model based on the effective media theory. The practical realization was carried out for East Uvat oilfield (West Siberia region). The area was divided in north and south parts characterized by different lithologic composition. The south part are characterized by limestone and sandstone with a small volume of shale, in contrast in south part the north part are characterized by polymict sandstone, siltstones and shales. The primary parameter adjustment for creating of petroelastic model was attended using wells with complete logs data. Further adjustment parameters implements using serial iteration of interpretative parameters that influence on elastic properties. A more iterations was necessary for wells without measured density and bad quality log data. Thus, petroelastic modeling solves the problems related not only with influence fluid saturation and lithologic composition on elastic properties of rocks, but also log data interpretation is more accurate with petroelastic modeling than without it. Our goal, in preparing this article, is to help illustrate the powerful role that rockphysics can play in well log interpretation.
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GIS-based Analysis for Petroleum Exploration - Case Study of Northern South America
Authors L. Bingham, A. Escalona and R. Zurita-MillaThe petroleum industry uses geographic information systems (GIS) for mapping and database needs as GIS elucidates spatial relationships between geologic and geophysical data. Generally, however, the petroleum industry does not exploit the full potential of GIS for analysis in exploration activities. Multi-criteria evaluation (MCE) combines data showing areas best fulfilling specific criteria. There are many different MCE methodologies, all of which are subjective. Petroleum exploration requires a method which is spatial, flexible for combining data, considers the data’s interpretive nature, is geologically applicable, and is applicable for frontier areas or where there is little information regarding probabilities of petroleum. This study created an MCE method for petroleum exploration based on fuzzy logic which fulfills the requirements above using 16 subcriteria and 1 constraint combined in tiers to produce a favorability map of potential exploration. A case study shows new exploration areas in the Cretaceous, Paleogene, and Miocene. By comparing known producing fields to the favorability outputs of one non-geologic-age-specific and three geologic-age-specific favorability maps in the case study, the method is validated. It is concluded that the method can be applied in an exploration setting and is applicable for other regions of the world.
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Prospects of Application of Geographic Information Technologies in Exploration for Oil and Gas
Authors M.A. Spikin, V.A. Pozdnyakov and S.S. HudyakovThe paper describes the experience in application of geographic information technologies and satellite imagery of high spatial resolution for solving practical problems in finding hydrocarbon deposits. It gives an example of a geographic information system based on WEB-technologies for making design decisions and monitoring exploration works in the Krasnoyarsk Krai.
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A Ghost-free Solution for Marine Seismic Acquisition
Authors Y. Ampilov, E. Fromyr and S.J. PharezThe ghost in marine seismic recording is the result of a reflection of the acoustic wavefield from the sea surface. Up-going waves are reflected back with reversed polarity, interfering constructively for certain frequencies and destructively for other frequencies dependent solely on source and receiver depths. Conventional marine seismic acquisition therefore involves a trade-off between the various frequency ranges. Recently a dual-sensor streamer, with collocated pressure and motion sensors, has been developed which removes the receiver ghost while maintaining the efficiency of towed streamer acquisition. A ghost-free source can be achieved with a time and depth distributed source using sub-sources deployed at specific depths and fired with specific firing time delays. The depths of the sub-sources are chosen such that the ghost functions are complementary, avoiding deep notches in the spectrum. Techniques for separating the wavefields from sub-sources have been developed that utilize the known firing time delays. The subsequent source ghost removal step involves re-combining those wavefields using well established techniques. De-ghosting or wavefield separation for source and receiver is based on first principle science and makes no restricting assumptions. The resultant seismic data has broader bandwidth both at the high end and the low end of the frequency spectrum.
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About Seismoprospecting Works on Water Area of the Nizhnekamsk Water Basin
Authors I.L. Dagaev, V.V. Chernyev and E.M. IgnatovaWork carried out now on generalization of all geologo-geophysical data will allow to specify potential resources of region.
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Comparison of Cable and Cableless Seismic Systems on Land and Marine
Authors Y.V. Roslov, V.A. Telbukhov, I.N. Kadurin and E.G. ZhemchuzhnikovNowadays cableless seismic is widely developed for land and marine applications. Comparing cable and cableless systems two key parameters have to be considered: data quality and operation cost. The data quality/operation cost ratio should be maximized in modern seismic. How to compare this ratio for cable and cableless systems? GeoEnergyGroup and SeismoShelf decided to joint efforts in order to carry out two filed experiments: land and marine for both systems simultaneously. SeismoShelf contributed with 4C seismic nodes and GeoEnergyGroup organized two test sites with on-going industrial acquisitions with cable systems. Finally two seismic surveys: onshore and offshore have been performed. Field data acquired with cable and nodal systems are demonstrated and discussed.
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