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3rd EAGE St.Petersburg International Conference and Exhibition on Geosciences - Geosciences: From New Ideas to New Discoveries
- Conference date: 07 Apr 2008 - 10 Apr 2008
- Location: Saint Petersburg, Russia
- ISBN: 978-90-73781-52-8
- Published: 07 April 2008
61 - 80 of 193 results
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3D Seismic Image of the Pulytyinskaya Ring Structure, West Siberia
Authors K. Sydykov, C. Einchcomb and A. ZhukovA seismic 3D survey conducted in 2005-2007 in West Siberia has revealed a ring feature, which complicates the reflections from the very top to the bottom of the sedimentary cover. To identify the nature of the feature, horizontal and vertical slices across the feature, as well as maps of the major reflectors have been studied. Comparison of the data with existing images and results of case studies shows that the feature, with its 4.5 km diameter and a distinct central uplift, bears a strong resemblance to a classic complex impact crater. The structure is marked by a conic fault. The crater can be recognized on the remote sensing image and on the elevation map. The data represents the first-ever example of a full 3D seismic image of a terrestrial impact crater. Along with 3D seismic image of the Silverpit impact crater in the North Sea, the data on Pulytyinslaka ring structure marks a new era of quantitative studies of terrestrial impact craters.
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Peanut Like Fold - the Role of Pre-existing Salt Diapirs
Authors J.P. Callot, J. Letouzey, D. Frizon de Lamotte, J.C. Riengenbach and S. SherkatiThe aim of the paper is to discuss the role of pre-existing salt structures on the Zagros folds development, within the Southern Zagros fold and thrust belt, which is characterized by the large extend of the Hormuz salt layer. We based our interpretations on geological observations, with comparison with analogue sand box experiments. Folds formed on top of a preexisting diapir display a peanut like shape on map view with a strong focusing of strain at the location of the former salt body.
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About Alpine, Post-Alpine and Modern Geodynamics of Ukrainian Carpathians Tectonosphere
Authors A.V. Nazarevych and L.Y. NazarevychНа основе комплексной интерпретации геофизических, геологических, геодезических, геоморфологических и других данных предложена схема современной и альпийской геодинамики литосферы Карпатского региона Украины и ее связи с геодинамикой Карпато-Балканского мегарегиона. Предложено объяснение определенных особенностей образования, развития и современной геодинамики различных приповерхностных и глубинных тектонических структур литосферы региона. Сделано заключение, что благодаря наличию здесь астенолита и вертикальной реологической расслоенности литосферы, а также действию в Карпатском регионе Украины вызванного глобальным процессом (надвиганием с юга Африканской и Аравийской плит) сжатия вкрест Карпат в период альпийского тектогенеза здесь были реализованные процессы по типу так называемой «крокодиловой» тектоники, приведшие к образованию Украинских Карпат. При этом верхние, в том числе осадочные слои (до глубин 10-14 км) надвигались в северо-восточном направлении на юго-западный край Восточно-Европейской платформы, а нижние слои пододвигались под него. Проанализированы также особенности геодинамики литосферы региона в следующие периоды, в том числе в неогеновую вулканическую фазу и вплоть до настоящего времени
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Strike-slip Faulting and Block Rotations in the Donets Basin
Authors V.A. Privalov and O.A. PanovaAlthough abnormal tectonic evolution of the Donbas segment within the Pripyat-Dnieper-Donets-Karpinsky (PDDK) palaerift has been long time recognized and studied, the driving mechanisms and mechanics of the basin uplift and inversion remain poorly understood. In 3-D view, the Donbas is a deformed prismatoidal block located on the intersection of the NNW striking Early Proterozoic weak corridor zone within the Sarmatian segment of the East European Craton and the Late Devonian PDDK rift. In our approach we consider the role of strike-slip and rotational deformations in controlling the distribution of releasing-restraining jogs and generating of re-active compression stresses responsible for formation of the Donets Foldbelt pop-up structure. Our constraints are based on the analysis of an extensive database of subsurface and underground geological information in combination with existing geophysical information.
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New Seismic Data on the South and North Chukchi Sedimentary Basins and the Wrangel Arch and Their Significance for the Geology of Chukchi Sea Shelf (R
During the summer of 2006 TGS-NOPEC conjointly with “Geophysical Solutions Integrator” acquired new seismic data in the Russian part of the Chukchi Sea. The area of the Chukchi Sea studied includes (from S to N): South Chukchi sedimentary basin (1), Wrangel Late Kimmerian Arch (2), North Chukchi sedimentary basin (3). Due to the absence of offshore wells in the Russian sector of Chukchi Sea, the interpretation of acquired seismic data and definition of probable hydrocarbon potential must be based on the comparison with the US sector of the Chukchi Sea and the Alaska North Slope, as well as on the geology of Northern Chukotka and Wrangel Island. In the northern part of the Wrangel Arch most of the thrust faults are N-vergent, but double-vergent transpressional structures also occur. To the North of the Wrangel Arch, a clearly recognizable angular unconformity in the upper parts of the North Chukchi basin may correspond to the Lower/Upper Brookian (~Cretaceous/Tertiary) boundary, although it may be as old as Early Cretaceous (pre-Aptian) in age. The maximum Pz-Mz-Cz sediment thickness of the North Chukchi basin exceeds 16 km. In the South Chukchi basin the thickness of sediments (Late Cretaceous?-Cenozoic) mostly doesn’t exceed 3-4 km, but in some places reaches 5-6 km. The geometry of the faults indicates an extensional/transtensional setting of the South Chukchi rift basin development. The changes in phase or polarity in upper parts of the sedimentary cover, listric fault planes in the pre-rift sequences, associated with areas of reduced reflectivity in the upper sediments may point to a gas presence. The syn-orogenic (pre-rift) Upper Jurassic-Lower Cretaceous organic-rich terrigenous sequence (containing visible plant remnants), which is exposed onshore in Northern Central Chukotka and is probably present in the Chukchi Sea, may represent regional gas source rocks.
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Geoindicative Analysis of Geophysical and Cosmic Geological Data for Oil and Gas Search
Authors Yu.N. Gololobov, A.I. Atakov and A.A. KirsanovThe method of tomographic geological sections construction based on the geoindicative geological and geophysical data has been fulfilled. Geoindicators is the fields of formalized signes of geological objects (subsurface substantial-structural nonuniform space), revealed during approximation of geophysical anomalies and processing of satellite images. Geoindicative analysis of geological and geophysical data is effective one on any stage of oil and gas prospecting. It’s results can serve as universal base for regularities of fields location studying and for development of forecast criteria.
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Tube-wave Reflections in Cased Boreholes
Authors D.V. Alexandrov, S.R. Ziatdinov, A.V. Bakulin and B.M. KashtanAt low frequencies tube or Stoneley waves represent a dominant arrival propagating along boreholes. It was proven in previous studies that 1D effective wavenumber approach provides simple and accurate low-frequency description of tube-wave propagation in open boreholes surrounded by radially homogeneous formation. In this study we apply 1D effective wavenumber approach to radially inhomogeneous media and demonstrate that it still provides excellent description of low-frequency tube-wave propagation. In particular, we focus on the models of cased boreholes: reflection from geological interfaces behind casing, reflection from corroded casing section and reflection from idealized disk-shaped perforation in cased hole. In considered cases frequency-dependent reflection coefficient obtained by 1D effective method and by finite-difference computations show excellent agreement.
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Investigation of Dependency of Elastic Wave Rate
Authors A.E. Sobolev, M.V. Chertenkov and A.N. KasimovBased on the measurements of kinematic and dynamic parameters of seismic waves, acquired data analysis and the correction of geological model of medium, it is proposed to study the extent of oil pool warming-up and the propagation of heated zone in order to estimate the effectiveness of warming-up during oil pool development. On the basis of VSP method we have tested an approach for the P-wave velocity estimation in the real geology conditions. It was determined that the warming-up of rocks saturated with heavy oils leads to the change of rock P-wave velocity. The influence of temperature on the velocity of P-waves on the different warming-up stages is different. Thus, on the basis of P-wave velocity measurements it is possible to define the position, size and movement of warming-up zone boundary in order to estimate the effectiveness of warming-up during oil pool development. This information is vital for the decision making regarding expediency and intensity of oil production.
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Wave Field Excitation in Thin Fluid-filled Fracture of Finite Size by External Seismic Wave and its Interaction
Authors G.A. Maximov, A.V. Derov, M.Y. Lazarkov, B.M. Kashtan and A. BakulinThe problem on excitation and propagation of slow eigen mode in thin fluid-filled fracture under action of external seismic wave is considered in the report. Based on averaging procedure the non-uniform pseudo-differential wave equation for slow eigen mode in fluid-filled fracture is derived in space-time representation for the long wave approximation by fracture opening. The derived wave equation takes into account strong dispersion of slow eigen mode and contribution of incident external seismic field. The space-time description of slow eigen mode in fracture allows to state and solve the boundary problem on the slow mode excitation by fracture tips and to estimate the contribution of this effect at the tube wave generation in a well. Numerical calculation show that the magnitude of this effect can achieve several percents of the principal tube wave amplitudes and hence it can be used for fracture size characterization.
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New Method for Improved Accuracy of Acoustic Measurements in Thin Bed Analysis
Authors R.D. Achmetsafin, D. Patterson and V. DubinskyThis new method has been tested with various data sets for normal and somewhat problematic acoustic logging data with various devices containing different size receiver arrays. The results demonstrate overall improvement in data quality and show promising results for robust acoustic data analysis with enhanced accuracy in thin-bedded environments.
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Cementation Factor Effect on Calculated Porosity and Water Saturation
Authors M. Mirzaee and M. Nabi-BidhendiThe Cementation factor (m) has an important role in the calculation of hydrocarbon/water saturations from electrical wireline logs. Cementation factor is determined by laboratory data. This is done by performing laboratory measurements on core plugs obtained during a drilling job. However, often these laboratory measurements are not available. In this study a series of sensitivity tests were carried out for a carbonate reservoir containing oil, in order to assess the relative impact of cementation factor (m) on log-derived porosity and water saturation. It is concluded that calculated water saturation increases with increasing cementation factor especially in low porosity rocks. Therefore, special care must be taken when dealing with low porosity carbonate rocks as water saturation is extremely sensitive to cementation factor.
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Capabilities of Induced Polarization Electrometry Using Scanning Lateral Logging Complex for Oil-and-Gas Boreholes Surve
Authors A.V. Gulimov, T.S. Mamleev, Y.V. Nikolaev and V.N. DanilenkoПоказана эффективность электрометрии ВП комплекса сканирующей модификации БК для оценки проницаемости карбонатных коллекторов и оценки текущей насыщенности в обсаженной стальной колонной скважинах.
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Development of VSP Data Acquisition and Processing Methods - Results and Future Promise
By G. ShekhtmanВ настоящее время при проведении исследований методом ВСП применяют одномерные (1D), двумерные (2D) и трехмерные (3D) модификации метода. Каждая из модификаций имеет присущие ей достоинства, недостатки и ограничения. На этапе проведения работ основная задача состоит в том, чтобы осветить должным образом изучаемый объект, обеспечив тем самым возможность корректной последующей обработки. Основным ограничением при проведении работ традиционными и нетрадиционными модификациями метода является сложная геометрия вышележащих границ. Поэтому для обеспечения существования в волновом поле падающих и отраженных волн требуемого типа перед проведением работ рассчитывают положение пункта возбуждения (ПВ), используя априорную информацию о покрывающей толще. При работах 2D-ВСП модификация ВСП с подвижным источником колебаний (ВСП-ПИ) обладает рядом преимуществ перед модификацией непродольного ВСП (НВСП), однако ограничением ВСП-ПИ является неустойчивость по латерали верхней части разреза. Это ограничение снимается на этапе обработки путем автоматического определения статического сдвига для каждого нового положения источника колебаний и/или зонда ВСП. Аналогичный подход применим к профильным и площадным модификациям 3D-ВСП. Современную скважинную сейсморазведку вполне можно рассматривать как многоволновую, высокоразрешающую и объемную, хотя далеко не всегда эти ее качества реализуются одновременно из-за условий проведения работ и поставленных задач. Положения доклада и возможности метода иллюстрируются экспериментальными и модельными результатами.
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Fractures Zones Determination for Carbonate Rocks on Bayandyskaya Field by Using FMI and VSP Data
Authors M.V. Chertenkov, A.N. Kasimov, V.V. kim, A.V. Pokul and T.N. KuptsovaOne of the most effective ways of fractures zones definition and characterization is wave pattern analysis of near wellbore zone in combination with azimuthal borehole measurements of receptivity’s heterogeneity of rocks. Obtained results allow us to evaluate qualitative characteristics for franko-zadonsky carbonate deposits and highly fractured intervals definition.
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Comparison of Different Approaches to 3D VSP Data Migration
Authors V.A. Mishin, S.I. Alexandrov and M.V. PerepechkinThe comparison of different 3D VSP migration methods was made on real data. The new techniques of spectral and finite-difference alghorithms is offered.
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Vector Representation of Wavefields
Authors A.N. Kasimov, I.A. Seleznev, S.A. Kasimov and V.A. RedekopThis work suggests an approach making it possible to identify wavefields on the basis of vector representation; at that, a vector determined in each, specified in advance, increment of the space by wave approach direction, and which is also described by a number o additional parameters. These parameters include: velocity, approach angle, azimuth, amplitude-frequency response, coordinates, and a number of other parameters.
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Active Thermometry During the Control of Development of Oilfield
Authors R.A. Valiullin, R.F. Sharafutdinov, N.V. Ovchinnikova and V.Y. FedotovOne of the perspective direction of the development of well thermometry is the use of artificial heat marks, which is concluded in the research of temperature distribution formation, caused by artificial heat source, for example during the inductive influence. It is an important task in the oilfield to determine the intervals of behind-the-casing flows. The nowadays thermometry can't solve this problems always, especially when it is observed the behind-the-casing flow from the "up". In the work it is given the results of theoretic and experimental researches of heat anomalies, caused by the inductive influence in the well with behind-the-casing flows. It is developed the mathematical model, taking into consideration the heat generation in the casing dusring the inductive influence, conductive and convective heat transfer in the radial and vertical directions, throttle heating of the fluid in the behind-the-casing space. For the experimental researches of heat distributions it is developed the well model. Analyze of theoretical and experimental researches shows the new approach to the well thermometry for the solution of problems of well technical condition estimation.
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Depth estimation of subsurface cavities using Hopfield Neural Networks
Authors A. Hajian, H. Zomorrodian and C. LucasThe method of Artificial Neural Network is used as a suitable tool for intelligent interpretation of gravity data in this paper. We have designed a Hopfield Neural Network to estimate the gravity source depth. The designed network was tested by both synthetic and real data. As a real data, this Artificial Neural Network was used to estimate the depth of a Qanat located in north entrance of institute of geophysics and the result was very near to the real value of depth.
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Crustal and Isostasic Model for North-West of Iran Plateau Using Gravity Data
Authors A Motasharreie, J. Piri, R. Kiamehr and H. ZomorrodianA new 3-D crustal model for North-West of Iran Plateau is presented base on the improved gravity database. The area consists of flat and mountainous regions. The Bouguer anomaly variations are of the order of more than three hundreds of miligals. In order to calculate the isostasic gravity residual a crustal model is assessed using the terrain model of the region. The higher frequency of the gravity signal and the terrain model are filtered using 2d discreet wavelet analysis. The thickness of the zero level roots is estimated by comparing with the new crust model. The synthetic gravity for the A-H model is calculated by Forsberg formula. Subtracting the synthetic gravity from the measured gravity, the isostasy residual anomaly for the region is calculated. Large positive anomalies are observed in Alborz mountains.
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Gravimagnetic Anomaly Formulae for Extended Homogeneous Prisms
Authors H. Holstein, C. Anastasiades and B. KetteridgeAnomaly formulae are known in closed form for homogeneous prismatic targets, as well as their limiting forms for prisms of infinitesimal or infinite extent, but the transition from finite to limiting form is numerically ill-conditioned. In the case of elongated prisms and thin sheets, we show how dominant terms in the polyhedral anomaly formulae can cancel analytically before numerical evaluation, allowing the limiting forms to be approached in a numerically stable way. We demonstrate the superiority of the new formulae over standard anomaly formulae by computing the relative anomaly deviation from the limiting form. Numerical breakdown is avoided in the new formulation.
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