Most of the currently known fields of the West Siberian oil and gas province are characterized by a complex geological structure and the presence of reserves difficult to recover. The development of these complex features will help maintain declining production from discovered and developed fields in Western Siberia. Efficient development of deposits of the Bazhenov formation and Achimov formation is possible only if there are objective ideas about the geological structure of these deposits. It seems important to link the features of the formation of these objects at the junction of the Jurassic and Cretaceous periods.
Based on the results of the detailed well log correlation of the entire well stock for the Nong-Eganskoye field, this article will show what processes took place during the formation of the Bazhenov-Achimov rock complex and their results. It has been established that the currently observed sharp "jumps" of the Bazhenov formation itself on the correlation schemes and seismic sections are the result of keyboard block subsidence along consedimentary faults. The analysis of structural and thickness maps of the anomalous section of the Bazhenov formation, the Bazhenov formation itself, and the Achimov compensation pack, showed almost identical outlines of the configurations of the positive or negative structures of the three studied objects, which indicate the tectonic nature of their formation. The use of such research methods as successive paleoprofiling and reduction of to one thickness made it possible to substantiate the formation of the Bazhenov-Achimov rock complex by tectonic movements. Genesis of this complex has a block character of multispeed subsidence of adjacent block. Undisturbed character bedding of rocks deals with different-velocity subsidence of the seabed in the same time interval within the blocks.
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