SPECIFIC ASPECTS OF OIL RESERVES DEVELOPMENT FROM DISCONTINUOUS LOW-PRODUCTIVE RESERVOIRS OF TYUMEN GEOLOGICAL INTERVAL (ON THE EXAMPLE OF JSC LUKOIL-WEST SIBERIA FIELDS)

Abstract

Research relevance. Middle Jurassic reservoirs are oil-bearing in 21 fields from total of 26 being produced by JSC LUKOIL-West Siberia in the Shaimsky oil-and-gas area, they contain 56 % of recoverable oil reserves. Middle Jurassic reservoirs have complex geological structure and are characterized by cross-sectional heterogeneity and lateral discontinuity, have low reservoir properties in general. Oil reserves in the reservoirs of Tyumen geological interval are classified as hard-to-recover based on the fields stratigraphy. Cumulative oil production from these reservoirs reached only 8,6 % from the total initial recoverable reserves as of 01.01.2021. Production rate is 0,4 % of the initial recoverable reserves per year. Research of the development of Tyumen geological interval reservoirs is a relevant exercise. The purpose of the research is to reveal key geological and geophysical features of the development of Tyumen geological interval reservoirs in order to identify the best methods and technologies to increase efficiency of their development. Subject: reservoirs of Tyumen geological interval in the Shaimsky area. Methods: literature research, analysis of the available experience of the development of Tyumen geological interval reservoirs based on the example of three fields of JSC LUKOIL-West Siberia. Executive summary. The paper analyzes and summarizes the specificities of geological structure, experience of the development of Tyumen geological interval reservoirs and the main methods of production enhancement and improvement of field development. Significant distinctions in the efficiency of field development are revealed based on the results of the carried-out analysis of geological and geophysical characteristics of the development of Tyumen geological interval reservoirs. According to the results of interpretation of the hydrodynamic researches conducted on considered fields, in two of them reservoirs with dual flow conditions (through both matrix and fractures) have been identified, which could have essential impact on the efficiency of development of these specified fields. Low performance of the development of Tyumen geological interval reservoirs is often caused by the use of uniform grid of the production wells, chosen due to insufficient knowledge of fields geological structure. The key issue is the evaluation of the recoverable reserves and the possibility to forecast production parameters using corresponding characteristics of oil drainage in accordance with the type of produced reservoir.

Keywords

• tyumen geological interval
• low-productive reservoirs
• dual flow conditions
• matrix and fractured reservoirs
• features of development
• hydrodynamic researches
• water injection