2nd EAGE St Petersburg International Conference and Exhibition on Geosciences

The genetic evolution of sedimentary basins involves basin formation, fill, and maturation of rocks and fluids within that basin.
The petroleum systems of Russia cover an extreme chronology from Pre-Cambrian to Recent for both source rock deposition as well as timing of petroleum emplacement. The oldest systems are driven by Riphean source rocks which matured under Vendian load and are reservoired in the ‘snowball-earth’ Vendian glacial deposits of East Siberia.
The evolution of these systems requires an understanding of Arctic, Tethyan, Atlantic and Pacific tectonics and their interplay.

As an example, the protracted Baltica – East Siberian craton suturing in the Uralian ruptures Paleozoic plays in West Siberia but sets up source deposition and loading in the Timan Pechora basin. The collapsed accretionary crust formed in West Siberia provides the substrate for Mesozoic deposition including the prolific Bazhenov source of the Late Jurassic. Trap formation occurs in West Siberia as a result of the far field effect of the India collision re-activating this older accretionary grain during peak petroleum generation.

This talk describes the petroleum systems of the major onshore provinces in Russia, linked to their controlling tectonic and depositional events.

The regional geophysical works, which were recently carried out by the use of the high technologies and equipment, extended the potential of oil-and-gas content of the different structures, explored during the preceding years.

The Aquitaine Basin is located in the south-western part of France, extending from the Gironde Arch to the north, to the Pyrenean Mountain Chain to the south. It corresponds to a triangular shape domain of 35000 km2 acreage. This presentation aims to describe the history and the dominant Petroleum System of the Aquitaine Basin including both its northern and southern domains. This is an original approach compared to most of the presentations already published.

Oil fields of the Timano-Pechorskaya oil-and-gas province (located in Nenetskiy autonomous national area of Russia) characterized by the complicated geology with sharp facies variations by lateral, steep slopes of the structures, pinch-out zones presence, large number of tectonic faults and non-anticline traps. These result in large number of ambiguousness of the geological and geophysical interpretation and, thereby, bring to difficulties in geological modeling.
Acoustic inversion results which are used in seismic interpretation process have some advantages since, firstly, both seismic and well data are used in computations. Also prior geological information can be included that leads to more stable result.
In the paper results of the acoustic inversion of the southern part of Inzyreiskoe oilfield are discussed. Single impedance cube was calculated for two target intervals – Middle Devonian terrigenous and Upper Devonian carbonate complexes. For Upper Devonian complex we managed to perform the facial classification and particularly define the high cavernosity and karsting zones. The main results for Middle Devonian complex are improvement in seismic correlation in zones with complicated interference patterns, correction of pinching out lines of sand reservoirs and definition of consolidation zones and shaling outs of reservoirs.

Пиролиз керогена 151 образца керна и шлама скв. № 11 Ванкорской, впервые в этом районе вскрывшей разрез средней и верхней юры, а также генетические корреляции типа «нефть-нефть» и «нефть-битумоид предполагаемой нефтематеринской свиты» привели к идентификации нефтяной яновстанской свиты и газоконденсатной среднеюрской (малышевская и вымская свиты) в качестве основных источников коммерческой нефтегазоносности.
Установлено, что нефти продуктивных пластов неокома принадлежат к одному генетическому семейству, связанному в основном с яновстанским источником нефти.
Юго-восточный Пендомаяхский очаг генерации углеводородов интенсивно функционировал в эоцен-плиоценовое время. Критический момент для яновстанско-неокомской системы наступил в раннемиоценовое время, а среднеюрско-неокомской – в позднеэоценовое. С этим периодом времени был связан активный этап формирования залежей нефти и газоконденсата в Ванкорском месторождении, который продолжается и в настоящее время. Вертикальное перераспределение в пределах Ванкорской структуры было особенно интенсивным на новейшем этапе тектонической истории района.

The geological risk quantification technique on perspective geological objects localizating, well position foundation and hydrocarbon resources estimation is considered. It bases on spatial reliability function and risk function stochastic estimation. We use structural mapping error and capacity characteristic crosswell-space error field simulation.

Reservoir description using seismic data has two major components: inversion of seismic data to extract attributes such as P- and S-wave velocities and bulk densities, and relate those parameters to reservoir properties, such as rock and fluid types, fluid saturation, porosity and pore pressure through fundamentals of rock physics. In seismic acquisition, we have seen considerable advancement that contributed to the quality of the seismic data, especially in the prestack domain. These are: single sensor recording (a large number of channels/offset), accurate and calibrated source and receivers and their positions, digital group forming, and towing cables at shallow water depths to minimize swell noise. All of these enable us to access surface seismic data with high S/N and fidelity that often rivals the fidelity of the Vertical Seismic Profiles (VSP).

In this paper, we use high quality seismic data to carry out Full Waveform Prestack Inversion to extract reservoir parameters, such as porosity and saturation. We use rock physics principles to constrain our inversion algorithm and then quantify our uncertainty using Bayesian approach that accounts for errors in upscaling and noise in the data and the model. We illustrate the entire procedure with examples from several basins.

A combined teqnique to predict reervoir properties from seismic inversion results is considered. Classification methods, multiple regression models and neural networks are employed to obtain predicted values of reservoir properties. A case history of porosity prediction, confirmed by subsequent drilling and geophysical survey, is provided.

To advance the mathematical and computational treatments of direct problems of the AVO involving multilayered media, a new derivation of the RT matrix method (reflection-transmission matrix method) is presented. This method allows calculate the complete dynamic response including both the displacement and stress fields in a layered half-space. The stability and accuracy of the direct problem’s solution are studied by numerical experiments on the model data. The synthetic seismogram building is realized. Based on actual data performance capabilities of the AVO inverse problems’ solution are investigated using iterative selections of models of the medium. It is shown that selection of models of the medium using a realized algorithm allows tracing the alterations of the medium parameters (bed thicknesses) between key wells.