Simulation on Deviatoric Fracture Propagation Path during Refracturing Process

Refracturing is an important technique treatment for enhancing oil or gas well productivity at the middle and late stage of low-permeability reservoir development. On the theoretical study of refracturing, most of researchers only focused on the reorientation of refracture while few studies focus on the refracture propagation path simulation. Due to the refracture propagation path depending on the stress field before refracturing, based on elasticity fracture mechanics and fluid-solid coupling theory, the mathematical solving model of induced stress field on the refracturing well is set up, which is combined with the propagation criteria of fracture, the computing method of refracture propagation path is deduced and the correlating calculation program is developed. The calculation results show that the reversal of stress orientation may occur owing to the effect of induced stress field near the well, and refracture will propagate at 90 degrees to the initial fracture azimuth at stress reversal region, until it reaches the stress isotropic point, where after, the refracture starts to reorient itself at some direction beyond the isotropic point, finally the refracture will propagate in a direction parallel to the initial fracture. For the simulation deviatoric path, the main factor affecting the refracture deviatoric distance is the straight length between the isotropic point and well bore, which perpendicular to the initial fracture azimuth.