Abstract: Staged multi-cluster fracturing technology is the key to the development of unconventional resources technology. The accurate understanding of the stress field change around the wellhole in the fracturing process is of great significance in fracture spacing optimization and reinforcing the effect of reservoir stimulation. Fractures-induced stress mathematical model was established based on the theory of elastic mechanics and displacement discontinuity. The model also takes into the consid-
eration the effect of wellbore pressure, in-situ stress, fracturing fluid seepage effect, thermal stress and perforation upon the stress field so as to find the strongest stress reversal zone as its object for optimization and thus to form a new inter-cluster fac- ture spacing optimization method. The results show that: for induced stress, the number in the direction of maximum horizon- tal principal stress and minimum horizontal principal stress direction is different and stress change is higher in the direction of maximum horizontal principal stress; the smaller the fracture spacing is, the more obvious the induced stress influence will be, and the smaller of the crack width in the middle becomes.