Abstract：Appreciation and prediction of micro-fractures in reservoir and verifying their distribution are important contents of integrative reservoir appreciation for micro-fractured reservoirs. Starting from analyzing the theory of plane stress field,the paper introduced mechanical mode for simple fold and composite structural mode and analyzed the theory of structural fracture. Onthatbasis,thepaper computed plane stress field. According to distribu-Lion and direction of major,minor principle stress and shear stress,the theoretical development for longitudinal,transverse and shear tensile fractures of paleo-structure and new-structure and its extenlion can be analyzed. The method was applied in W2 fault block which gained a good result.
