SIMULATION STUDY ON THE INFLUENCE OF ROCK EXPANSIBILITY ON THE PREDICTION OF IN-SITU STRESS UNDER HIGH TEMPERATURE CONDITION

In the process of oil and gas resource geological exploration, mastering the geostress and distribution state is one of the most important problems. However, the distribution of initial in-situ stress field is affected by many factors. How to improve the accuracy of in-situ stress inversion field is an urgent problem to be solved. Finite element analysis has become one of the current mainstream in-situ stress prediction schemes because it can better fit the reality. However, with the increase of measurement depth, the rock mass expands at different temperatures, and the resulting thermal stress will have a certain impact on the original in-situ stress field. The influence of temperature stress produced by thermal expansion of rock on the distribution of initial stress field is analyzed by considering the topographical structure, temperature and other factors. The results show that with the increase of the linear expansion coefficient, the temperature stress produced by the thermal expansion of rock shows a gradual increase under the displacement boundary conditions and stress boundary conditions. Under the displacement boundary condition, affected by the temperature gradient, the amplitude of the initial stress field value decreases gradually with the increase of the measurement depth and tends to be stable. Under the stress boundary condition, affected by the temperature gradient, the amplitude of the initial stress field value increases with the measuring depth and the increment increases gradually.