Abstract: The numerical simulation and fractural prediction of paleotectonic stress field of $E^2_3$ reservoir in Wellblock YH-1 of Gaskula oilfield, Qaidam basin are made with finite element method, and the paleotectonic stress field of distributed main oil zones and their fractural orientation and density distribution characteristics are obtained. It shows that there exist differences of the fractural orientations in different tectonic parts and different depths, with NEE and NWW for the shear fractures, near EW for the lateral tension fractures and near SN for the vertical tension fractures. In axis and higher parts of the tectonic, fractures develop well than flank and lower parts, and with increase of the tectonic buried depth, fractures tend to more and more development.

Key words: Qaidam basin, Gaskula oilfield, reservoir, stress field, numerical simulation, fracture