Research on stress alternation effects and fracture reorientation for refracturing treatment

Trying to induce fracture reorientation in refracturing is important because it means stimulating areas with more residual oil and intersecting less depleted pressure. To verify the possibility of reorientation during refracturing, a hydraulic–mechanic coupling model is built and solved using COMSOL Multiphysics based on poroelastic and seepage theory; pore porosity and strain change of formation are analyzed and verified to alter the stress around the fracture; then the dynamic stress field of depleting development is obtained; factors that cause the alternation of stress are analyzed by comparing the altered minimum and maximum horizontal stress; and the area of stress reversal region is calculated. To further evaluate the oil recovery of different angles of reoriented fractures, geological and numerical models are simulated using data of an actual reservoir with a rhombus inverted nine spots well pattern. The results show that producing underground liquid leads to a change of the pore pressure and the ...