Abstract: Qingxi oilfield is a fractured reservoir. The fractures are the main oil-gas reservoir space and controlling factors for petroleum enrichment. To well predict the distribution area and development extent, finite element method (FEM) is applied to make numerical simulation of tectonic stress field for No.1 and No.3 members of Xiagou formation. According to the data of structural evolution, core and well logging，this paper suggests that the effective fractures of Qingxi reservoir were mainly formned in period of Himalayan orogeny. The main types of the fractures are dip-crossing fracture with low angle, interlayer fracture and few high angle fractures. According to the numerical simulation results and Coulomb-Mohr's criterion of fracture, these structural fractures are predicted. The result shows that the fractures are generally developed in this studied area. The major fractured areas are located in eastern and southern Qingxi oilfield. And the high-yielding wells are all situated at the well fractures areas. So these areas are favorable ones for oil-gas exploration and development.

Key words: Qingxi oilfeld, finite element method, tectonic stress field, numerical simulation, fracture, prediction