Conceptual sedimentation model as the basis of geological correlation in a case study of AT6-8 reservoirs of Beregovoye field in West Siberia

Abstract

For the Beregovoye field (West Siberia, Yamalo-Nenets Autonomous Okrug), a new subsurface geologic model for AT6-8 group of reservoirs in the Lower Cretaceous (Hauterivian-Aptian) interval within Ereyamskaya formation was built following the reprocessing and reinterpretation of 2D and 3D seismic data in 2020, drilling of new wells (new wells, which were drilled after 2016, account for about 10 % of the total well stock that penetrated the AT6-8 reservoirs), updating the structural framework, additional core studies, and revising the well test results. Well log correlation in the AT6-8 interval was based on the reservoirs formation in alluvial and tidal delta plain environments. Multidirectional source areas formed disconnected zones in the net reservoir interval, which controlled the oil and gas content of these reservoirs. Taking into account the results of the geochemical survey, a stage-by-stage approach to hydrocarbon accumulations (light oil and gas condensate) formation was proposed, which led to vertically and laterally varied phase compositions of the discoveries.