«Oilfield engineering»

Impact of sedimentation conditions of Tyumen formation on the oil reserves recovery

UDC: 622.276.43
DOI: 10.33285/0207-2351-2022-9(645)-19-24

Authors:

¹ Industrial University of Tyumen, Tyumen, Russia
² LUKOIL-Western Siberia, Kogalym, Russia
³ LUKOIL-Engineering Limited KogalymNIPIneft Branch Office in Tyumen, Tyumen, Russia
⁴ LUKOIL, Moscow, Russia

Keywords: Tyumen geological interval, low-productive reservoirs, dual flow conditions, matrix and fractured reservoirs, features of development, core analysis, production profile

Annotation:

In 21 oilfields being developed by LUKOIL–Western Siberia LLC in Shaimsky oil- and gas-bearing region 36 % of recoverable oil reserves are accumulated in the Middle Jurassic reservoirs. These intervals are of complex geological structure and characterized by cross-sectional heterogeneity and discontinuity, have low reservoir properties in general. Therefore, oil reserves in the Tyumen geological interval reservoirs are classified as hard-to-recover ones. As of 01.01.2022, the share of the remaining recoverable reserves is over 64 %. Recovery rate from the initial recoverable reserves – 1,2 % per year. Thus, research of the development of Tyumen geological interval reservoirs is a relevant exercise.

The purpose of the research is to reveal the key geological-physical features of the Tyumen geological interval reservoirs in order to identify the best methods and technologies to increase the efficiency of their development by applying the following methods: literature analysis, analysis and generalization of the available experience of the development of Tyumen geological interval reservoirs based on the example of three fields of LUKOIL–Western Siberia LLC.

The specificities of the geological structure, the results of the reserves recovery from Tyumen geological interval reservoirs are studied and the main trend of the development technology improvement is substantiated. Significant differences in the efficiency of oil reserves recovery are revealed. According to the results of the facies analysis and the study of the core from the three fields, the correlation between the sites of high production rates and the reservoirs of alluvial river deposits with dual media is revealed. Two out of three concerned fields have more than 15 % of the reservoirs associated with such deposits, while the third field has less than 8 %. Low development efficiency of the Tyumen geological intervals the designing of which was done on the geologically insufficient information about the deposits is revealed.

The geological-hydrodynamic models were used to evaluate the recoverable oil reserves and prediction of the oil recovery volume of a porous-fractured reservoir was performed by applying displacement characteristics corresponding to the type of a production formation.

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