Abstract：Refracturing is an important technique for enhancing or stabilizing well productivity in the low-permeability oilfield. The reorientation of refracture is fairly difficult and most important in refracturing. The refracture orientation depends on the stress field in vertically-fractured gas well. The stress field，especially the orientation of horizontal principal stress in vertically-fractured gas well，determines the azimuth of refracture creation and refracture propagation. The stress characteristics of vertically-fractured gas well and the main factors affecting the change of stress value and the stress orientation are studied systematically. It is proved that the induced stress resulting from the initial hydraulic fracture and the variation of pore pressure resulting from production can change the distribution of stress field of the gas well and lead to the reorientation of stress field. Using the theory of elasticity and fluid-solid coupling，the mathematical model of induced stress of refracturing gas well is set up and the software is developed to quantitatively analyze and simulate the stress filed before refracturing for vertically-fractured gas well. The application to Xinchang gas field shows that the initial differential stress and production time are the key factors to determine the stress reorientation in refracturing gas well.
