— The paper considers the geologic structure of the region and the current problems and prospects for the development of its energy potential and environmental safety. We provide grounds for the necessity of integrated projects aimed at studying the deep structure of the Caspian region as a single object by its five coastal states: Azerbaijan, Iran, Kazakhstan, Russia, and Turkmenistan. The proposed Geokhazar project is aimed at obtaining the lacking parametric geological and geophysical information about the deep subsurface structure of the water area of a sedimentary basin in the unique intracontinental catchment of the Earth. The project provides for the development of a universal prospecting concept taking into account the emplacement and conservation of hydrocarbon fields under severe thermobaric conditions at great depths and the absence of regionally consistent drainage systems; the determination of the factors influencing the nature of long- and medium-frequency eustatic fluctuations in the Caspian Sea level; and the assessment of the energy (geothermal and hydrocarbon) resources of the deep subsurface in the Caspian, cis-Caucasian–Mangyshlak, and South Caspian oil and gas provinces.

The authors have proposed a scheme for the formation of the hydrocarbon capacity of the West Siberian oil and gas basin in a paleosubduction geodynamic setting and continue developing the idea concerning the abiogenic deep genesis of hydrocarbons due to the low-temperature serpentinization of mantle peridotites during spreading in the Ordovician back-arc basin, which occupied at that time within the area of the future West Siberian basin, and the high-temperature hydration of peridotites in the mantle wedges above the subduction zones during the Selurian and Devonian. Another source of abyssal hydrocarbons is the serpentinization of mantle peridotites fragments in water saturated basement. A major role is being established in the formation of hydrocarbon deposits in the sedimentary cover of Western Siberia in the vertical migration of deep hydrocarbon fluids through degassing pipes, including anomalous annular zones, through deep thrusts, which are active gas-oil supply channels and along a large zone of Neogene-Quaternary low-amplitude horizontal shifts in the basement thickness. Deep-seated faults that comprise triassic rift system of West Siberian play a major role in water removal from deep sources. The feeding with new portions of oil and gas in hydrocarbon fields of West Siberian basin continues in present time, which provides renewability of regional hydrocarbons. The total volume of methane generated in the serpentinization zones of mantle peridotites is formed from two sources — abiotic (reaction of hydrogen with carbon dioxide dissolved in seawater) and biotic (methanogens). The origin of hydrocarbons is considered in the context of a new polygenetic scheme of oil and gas formation in the process of «abiogenic-biogenic» synthesis.

Global experience in oil exploration and the discovery of the Tupi field in Brazil and the Tiber field in the Gulf of Mexico in the last decade have confirmed the existence of giant oil fields with abnormally high formation pressures at depths of 10 km or greater. Until recently, the discovery of large oil accumulations in deeply buried reservoirs was considered as theoretically impossible. This work suggests that giant oil accumulations at great depths (6–10 km) should be considered important hydrocarbon exploration targets in the Russian Federation and the countries of Eurasian Economic Union. The first-priority oil and gas exploration targets at great depths are deeply buried horizons of the sedimentary cover of the Precaspian basin, whose subsalt hydraulic system is characterized by ubiquitous abnormally high formation pressures. The deeply buried reservoirs in the Astrakhan oil and gas accumulation zone are considered the most promising for the discovery of giant oil accumulations.

Мировой опыт нефтепоисковых работ последнего десятилетия и открытие месторождений Тупи в Бразилии и Тайбер в акватории Мексиканского залива показал существование гигантских месторождений нефти в условиях аномальных давлений на глубинах 10 км и более. До настоящего времени возможность обнаружения крупных скоплений нефти на больших глубинах считалось теоретически невозможным. В работе предлагается рассматривать поиск гигантских скоплений нефти на больших глубинах (6–10 км) в качестве одного из актуальных направлений геологоразведки на территории Российской Федерации и стран Еразийского экономического союза. Первоочередными объектами поисковых работ, связанными с выявлением залежей нефти и газа на больших глубинах, рассматриваются глубокие горизонты осадочного чехла Прикаспийской впадины, подсолевая гидросистема которых повсеместно обладает аномальными высокими давлениями. Наибольшие перспективы обнаружения гигантских скоплений нефти связываются с изучением глубокопогруженных залежей в Астраханской зоне нефтегазонакопления. Показано, что поиски и обнаружение гигантских скоплений нефти на больших глубинах требует особых условий ведения геологоразведочных работ.

Предложена новая техника интерпретации данных пассивного сейсмического мониторинга, позволяющая на основе учета напряженно-деформированного состояния в зоне ГРП уточнять геометрию гидроразрывов. Эта техника опробована на экспериментальных данных скважинного пассивного сейсмического мониторинга ГРП на нефтяных месторождениях в Республике Казахстан и в Западной Сибири.

Specific deformation patterns in sediments associated with small-amplitude strike-slip faults in the basement have been recognized over a large territory of the West Siberian basin due to 3D seismic exploration advance. These patterns represent shear structures which turn to be a phenomenon beyond the classical views of the regional basin architecture. Many densely faulted oil and gas fields of a complex geometry in reservoir rocks of a wide stratigraphic range fall in zones of shear structures. Prospecting, test drilling, and oil enhancement activities in these fields are risky without a solid mechanic and kinematic background based on simulation of sedimentary fracture patterns which are associated with basement-involved strike-slip faults and may govern hydrocarbon migration as structure controls, fluid channels, or screens.

The problem considered is necessity and possibility of automatic well-to-well correlation, for oil fields having a big number of wells. The conclusion is made that successful strategy is to find a compromise between formal automatic and informal interactive tools. Two different automatic procedures are analyzed, first one implemented in AutoCorr program and the second in DV-Geo modeling system. The analysis shows that the compromise existing in one system is complimentary to the compromise existing in the another. Thanks to this feature, joint correlation processing in AutoCorr and in DV-Geo becomes very efficient. New automated technology is realized by each system updating in part of share data processing tools. Examples of the technology application are shown as well.

Сейсморазведка 3D впервые выявила в осадочном чехле Западно-Сибирской плиты необычный парагенез структур, осложняющий нефтегазоносные брахиантиклинальные поднятия. Он представлен в плане линейными системами кулисообразно расположенных малоамплитудных сбросов, приуроченными к сдвигам в фундаменте. На разных крыльях сдвига сместители сбросов падают в противоположные стороны, образуя структуру, напоминающую лопасти пропеллера. В разрезе, параллельном сдвигу, границы слоев и сместители сбросов также падают в противоположных направлениях. В сечении вкрест простирания сходящихся к фундаменту сбросов слои обрисовывают антиформу с “просевшим” по сбросам сводом (структура “цветка”). Данный структурный парагенез сформировался в результате интерференции полей напряжений горизонтального сдвига вдоль вертикальной плоскости (порожденного сдвигом в фундаменте) и горизонтального сдвига вдоль горизонтальной плоскости (обусловленного “гравитационным” сопротивлением чехла); при этом смещения по сбросам в чехле происходили как в вертикальном, так и в большей степени в горизонтальном направлениях, так что по существу разрывы чехла являются сбросо-сдвигами. Генеральной причиной сдвиговых перемещений вдоль разломов фундамента, имеющих СЗ и СВ простирание и образующих в плане ромбовидную систему, является общее для Западно-Сибирской плиты субмеридиональное сжатие. В крупных новейших сдвиговых зонах Западной Сибири встречаются нефтегазоносные брахиантиклинальные поднятия, оси которых, вопреки канонам тектонофизики, ориентированы в направлении, близком к направлению оси максимального сжатия. Наши эксперименты с эквивалентными материалами показали, что возможной причиной их формирования является локальное поле напряжений, которое возникает вблизи окончаний формирующихся в зоне сдвига эшелонированных сколов Риделя. Прогрессирующее удлинение последних вызывает соответствующее удлинение брахиантиклиналей, расположенных между их концами. Проведенное исследование показало, что к известным типам интерференции элементарных геодинамических обстановок, таким как горизонтальный сдвиг вдоль вертикальной плоскости + горизонтальное сжатие (транспрессия) и горизонтальный сдвиг вдоль вертикальной плоскости + горизонтальное растяжение (транстенсия), можно добавить сочетание того же горизонтального сдвига вдоль вертикальной плоскости с горизонтальным сдвигом вдоль горизонтальной плоскости, вызывающим тектоническое расслаивание (lamination). Мы предлагаем назвать этот тип интерференции элементарных сдвиговых геодинамических обстановок, по аналогии, “трансламинацией”. Именно в геодинамической обстановке трансламинации и возникают нефтегазоносные структуры “пропеллерного” типа.

Strike-slip fault structures have been identified with confidence in the vast area of the West Siberian north and characterized in detail by the Central Geophysical Expedition. Various structural paragenesis of strike-slip deformations ranging from drag folds arranged in an echelon manner and early shear systems to linear suture zones of rock mass discontinuities in the sedimentary cover can be mapped there. Strike-slip fault structures have been identified in a giant territory extending from the southern border of the Yamal-Nenets Autonomous Area up to the polar latitudes, covering an area of over 500 thousand square kilometers and holding largest hydrocarbon deposits. The study of hydrocarbon fields shows a significant impact exerted by strike-slip faults on the formation of hydrocarbon deposits, on regularities in their spatial-stratigraphic distribution, on reservoir properties and sealing ability of rocks.

An unusual structural paragenesis, complicated by brachyanticlines, is revealed for the first time in the sedimentary cover of the West Siberian Plate by 3D seismic surveying. These are linear (in plan view) systems of en-echelon arranged low-amplitude normal faults related to wrench faults in the basement. On different sides off a wrench fault, the planes of normal faults dip in opposite directions, forming a helicoidal structure that resembles the blades of a propeller. In the section parallel to the wrench fault, the boundaries of the beds and normal fault planes dip in opposite directions as well. In the section across the strike of the normal faults converging toward the basement, the beds take the shape of an antiform with a crest sagged along the normal faults (flower structure). This structural assembly was formed as a result of interference of stress fields of horizontal shear in the vertical plane (induced by faulting in the basement) and in the horizontal plane (caused by gravity resistance of the cover). In this case, the displacements along the normal faults develop in both the vertical and, to a greater extent, horizontal directions, so that the faults in cover are actually characterized by normal-strike-slip kinematics. The regional N-S-trending compression of the West Siberian Plate is the main cause of shearing along the NW- and NE-trending faults in the basement, which make up a rhomb-shaped system in plan view. Petroliferous brachyanticlines, whose axes, notwithstanding tectonophysical laws, are oriented in the direction close to the maximum compression axis, are known in the large wrench fault zones of Western Siberia. Our experiments with equivalent materials showed that a local stress field arising at the ends of echeloned Riedel shears within a wrench fault zone may be a cause of the formation of such brachyanticlines. The progressive elongation of Riedel shears leads to the corresponding elongation of the brachyanticlines located between their ends. The performed study has shown that the known types of interference of elementary geodynamic settings such as horizontal shear along the vertical plane + horizontal compression (transpression) and horizontal shear along the vertical plane + horizontal extension (transtension) may be supplemented by combination of horizontal shears along the vertical and horizontal planes, resulting in tectonic lamination. By analogy, we propose to name this type of interference of elementary shear settings translamination. Petroliferous helicoidal structures arise in the given geodynamic setting of translamination.

H038 Automatic Well-to-Well Correlation Based on Consecutive Uncertainty Elimination E.V. Kovalevskiy* (Central Geophysical Expedition JSC) G.N. Gogonenkov (Central Geophysical Expedition JSC) & M.V. Perepechkin (Central Geophysical Expedition JSC) SUMMARY The problem considered is a detailed well-to-well correlation of log data for oil fields with a developed borehole grid. Special software is designed with automatic correlation procedure for log intervals of 60-80 m long as a main part of it. An automatic procedure is based on (1) correlation uncertainty presentation in the form of alternative assumptions and on (2) subsequent algorithm for uncertainty elimination which implements logical reasoning on a triangulation