Geological justification for increasing the efficiency of development of deposits of hard-to-recover oil reserves in the collectors of the Tyumen arch of the Surgut (Western Siberia)

Abstract

The article deals with the results of studies of the geological structure features of the US2 oil-bearing stratum in the upper part of Tyumen suite (a case study of the Surgut arch fields). Object US2 is represented by low-permeability reservoirs with complex facies variability and an uneven distribution of reservoir properties over area and section, characterized by a thin-layered structure. In this regard, the oil reserves of the US2 structure are naturally classified as hard-torecover, requiring additional work to further study its structure and features for effective development of oil reserves. The facies of river channels, riverbank shoals and sands of floodplain spills were identified, based on the analysis of geological and geophysical materials: 3D seismic survey, core studies, well testing data, sampling and dynamics of wells operation in the area of the deposits in the upper part of the US2 horizon. Based on the analysis of the detailed correlation, three types of section of the US2/1 formation were identified, differing in the nature of the reservoir spread. Based on the 3D seismic survey data, in order to clarify the structure of the US2 formation, a dynamic analysis of the attributes of the seismic record was carried out. Significant coefficients of cross-correlation between the dynamic characteristics and production parameters of the US2/1 formation were not obtained. It is necessary to develop optimal methods for exploration and clarification of the features of the geological structure and forecasting the distribution of reservoir properties, rational methods and approaches to the development of hard-to-recover reserves of Tyumen suite objects with a complex distribution of reservoir properties and variability of productive thicknesses.