Loading diagrams and parameters of the model of elastic-pseudoplastic deformation of black shale rocks of the Bazhenov formation

Abstract

The results of the analysis of experimental data on pseudotriaxial loading of full-size samples of black shale rocks of the Bazhenov Formation are presented. The experiments were carried out under conditions of uniaxial loading and at lateral compression pressures of 20 and 40 MPa. It is shown that in the considered load range, the deformation of the rock beyond the elastic limit proceeds in different modes: dilatancy and compaction. Despite the low porosity of the rock, the transition from dilatation to compaction occurs at a pressure not exceeding 34 MPa. Based on the analysis of the obtained data, the stages of deformation in the loading diagrams are distinguished and the parameters of the mathematical model with a combined limiting surface are determined, which describes the deformation process in dilatancy and compaction modes.