NUMERICAL SIMULATION OF STRUCTURAL STRESS FIELD IN FUNING SEDIMENTARY PERIOD AND PREDICTION OF THE DEVELOPMENT LAW OF LOWER-ORDER FAULTS IN CHAJIAN SLOPE ZONE

Chajian slope zone is located in the south of the western slope, Jinhu sag. It has mainly experienced the Wubao and Sanduo tectonic movements during the sedimentation in Tertiary, which formed the complicated fault system and made it into a complex fault-block reservoir. There are many lower-order faults in this area, which makes great influence to the reservoir description and the development deployment, but they cannot be described correctly only based on the seismic data. The determination of the structural stress direction in Funing sedimentary period, which is NW350°, is based on the areal description of the faults. The method of numerical simulation of tectonic stress was applied to make the geological model and simulate the description of structural stress in Funing sedimentary period. The development law of the lower-order faults was predicted according to the description of structural stress. The results show that the maximum and the minimum principal stress were both in the horizontal direction, which usually forms tenso-shear faults. The development of the lower-order fault is mainly influenced by the difference between the maximum and minimum principal stress and the shear stress. In other words, the difference between principal stresses control the advantage area of the fault development, the plane shear stress control the strike of the fault, and the profile shear stress control the dip direction.