Abstract: Based on the rules of rock fracture, the relationship between the paleo- and present stresses and the fracture parameters is established, and the feature and direction of paleo-stress during the fracture initiation period are determined by structural analysis. The present stress' direction and size are calculated using sonic velocity, hydraulic fracturing and acoustic emission methods. By substituting the fracture parameter calculation model into the numerical simulation result of the paleo- and present stress fields, the fracture aperture, porosity and density of the Permian volcanic reservoir in Tahe oilfield are simulated and calculated. The fracture parameters from the core observation and log interpretation are used to plot the contour map of fractural line and volume density in the whole area for verification. The result shows that the simulated results are reliable.

Key words: Tarim basin, Tahe oilfield, volcanic rock, fracture, numerical simulation, stress field