Chistyakova 4-2024

N.F. Chistyakova, V.D. Nemova, M.D. Subbotin

West Siberian Bazhenov rocks: deformation behaviour and strength properties

DOI 10.47148/0016-7894-2024-4-41-54

Key words: Bazhenov formation; high-bituminous argillaceous-carbonate-siliceous rocks; Organic Matter; deformation behaviour and strength properties; crack formation; secondary reservoir; brittleness index.

For citation: Chistyakova N.F., Nemova V.D., Subbotin M.D. West Siberian Bazhenov rocks: deformation behaviour and strength properties. Geologiya nefti i gaza. 2024;(4):41–54. DOI: 10.47148/0016-7894-2024-4-41-54. In Russ.

The authors present the results of laboratory analysis of lithological composition, Organic Matter content, deformation behaviour and strength properties of 35 samples of Mesozoic Bazhenov bituminous argillaceous-carbonate-siliceous rocks taken in Sredneobsky Petroleum Region. According to the content of main rock-forming components and Organic Matter, the studied samples are classified into three lithological types, they are: high-carbon argillaceous-siliceous-carbonate and carbonate-argillaceous-siliceous, and carbonaceous argillaceous-siliceous rocks. Each lithotype is characterized by specific values of the parameters studied. It is found that the increase in Organic Matter content in rocks is accompanied by a change in the breaking strength of bituminous rocks, which impacts on their deformation behaviour and strength properties. The first cracks appear in high-carbon argillaceous-siliceous-carbonate (coccolithophorid-bearing) rocks containing 19% of Organic Matter on average at overburden load of 66.9 MPa; next — in the high-carbon carbonate-argillaceous-siliceous rock containing 12.5 % of Organic Matter at overburden load of 67.4 MPa; and then — in carbonaceous argillaceous-siliceous rocks containing 7 % of Organic Matter on average at overburden load of 71.6 MPa.