Impact of block tectonics on mode of BS3 reservoir occurrence in Tevlinsko-Russkinskoye oilfield

The paper presents the findings of a research study of BS102+3 reservoir geology, including classification of well logs based on thorough correlation between stratum thicknesses and their quantities. Hydrodynamic study has allowed us to confirm the occurrence of faults, review their impact on connectivity across BS102+3 reservoir and reveal potentially bypassed areas for further investigation, completion and enhancement of oil recovery factor. It has been found that distribution of facies is related to NS tectonic deformation.
Materials and methods
Basic values for the research have been derived from logging data of 2500+ wells of Tevlinsko-Russkinskoye oilfield, as well as core data, seismic and hydrodynamic data, and archive records on geophysics, lithology, survey and other studies. Research methodology, used to study geology of Early Cretaceous deposits, is based on automatic correlation of well logs with Autocorr software and proven technique of integration of logging, seismic, core and geological field data.
Results
The devised classification has provided for scientific justification of radically new block structure model of BS102+3 reservoir with a stepwise pattern of change of oil-water contact (OWC) in Tevlinsko-Russkinskoye oilfield. Fault blocks are characterized by well logs of a certain type. The field study has revealed that there is a link between changes of bed thickness in BS102+3 reservoir and minor faults, which are not traced by seismic data and which determined stepwise pattern of OWC change. The paper suggests there may be areas of oil, bypassed during reservoir development, resulting from minor tectonic faults. It has also been explored how lateral tectonics impact lithofacies zoning, degree of hydrodynamic connectivity of adjacent blocks across BS102+3 reservoir and orientation of river network on the surface.
Сonclusions
Data acquired from detailed correlation of well logs of Tevlinsko-Russkinskoye oilfield along with seismic, coring and geological field data have been implemented and practiced at OOO LUKOIL-West Siberia. They may be further used to estimate hydrocarbon reserves and review design solutions in the course of development of Early Cretaceous deposits in Tevlinsko-Russkinskoye oilfield.