Prospects of productive strata of the pre-Jurassic complex of Western Siberia for the discovery and involvement in the development

   The article discusses the prospects of productive strata of deposits of the pre-Jurassic complex of Western Siberia for searching, forecasting and involving in the development. Some features of the geological structure of Triassic volcanic-sedimentary deposits and formations of the Paleozoic basement have been identified within the pre-Jurassic complex. The construction of digital geological models of Triassic and Paleozoic formations, which are fundamentally different in the geometry of the internal structure of the hydrocarbon deposits discovered in them, is based on 3D seismic information and its interpretation. In deposits of Triassic and Paleozoic sediments, significant differences in the composition and filtration-capacitive properties of rock reservoirs have been recorded; the principles for creating the structural frameworks of their digital models are also different. 3D seismic data makes it possible to correlate the Triassic strata and identify individual cycles, the boundaries and geometry of which are used to create digital three-dimensional geological models. When creating models of hydrocarbon deposits in Paleozoic formations confined to basement high areas, based on the interpretation of 3D seismic survey materials and analysis of seismic attributes, in combination with information on core, petrophysics and well testing, a forecast is made for the development of areas and strata of increased fracturing of rocks, which are the main inflow strata in production wells. Using the example of individual developed deposits confined to the pre-Jurassic complex in the fields of Western Siberia, the actual results of integrating geological and geophysical information with 3D seismic data are shown. Based on these results not only an assessment of the geological reserves of hydrocarbons was carried out, but also hydrodynamic calculations were conducted to perform history matching, as well as recommendations were made for the locations for drilling wells, their geometry and test strata. The accumulated experience in exploration and development of productive deposits of the pre-Jurassic complex allows us to assess the geometry and features of objects of interest in this interval, select the most informative methods for their mapping and methods for creating digital geological models that are the basis for designing the development.

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