Mechanical Behaviors of Deep Reservoir Rocks: An Experimental Study and Elastoplastic Constitutive Analysis

Abstract

The deep earth is rich in resources. However, the combined increase in the confining pressure and temperature enhances the rock plasticity, which severely restricts efficient development. This study conducted rock compression experiments that involved different combinations of pressures and temperatures. According to the findings, the confining pressure primarily enhanced rock plasticity, while temperature exacerbated plasticity under confining pressure. Applying pressure prevented the rapid development of heat-induced microcracks, ultimately improving plasticity. An elastoplastic constitutive model was established that considered nonlinear hardening, while the model parameter changes at different buried depths were investigated. This offers a novel method for characterizing the mechanical properties of reservoirs with varying buried depths. The finite element secondary development method was used for numerical realization, while the accuracy of the model was verified via comparison with the experimental results, the correlation coefficient was 92.3%. This allowed for the effective delineation of the mechanical deep reservoir characteristics, providing theoretical support for related engineering design.