Abstract: Various conditions and stress mechanisms result in the complicated tectonic settings of the Kunbei fault terrace belt. Two series of tectonic simulation experiments are designed for the primary-order and second-order main faults, and the third-order and other secondary order faults, respectively. The first series of experiments simulate the primary-order and second-order main faults and the results reveal that a series of unbalanced thrust fault systems are developed on the Kunbei fault terrace belt under the continuous compression of N-S trending tectonic dynamics during Himalaya orogeny, which highly matches with the 5 seismic interpretation sections in the study area. The second series of experiments simulate the third-order and other secondary order fault structures and suggest that these faults are controlled by the maximum shear stress, in which 2 fault systems including conjugate reverse fault and tearing reverse fault are developed, which matches with the characteristics of fault systems displayed on the time slices in the study area. The numerical simulation results can further verify the conclusions of the 2 series of experiments and show that the secondary fault systems can improve the accumulation properties of reservoirs. Wellblocks of Qie-16, Qie-6, Qie-12 and Qie-4 in Kunbei oilfield have been proved to be the hydrocarbon enrichment areas, which well matches with the experiment results and can be the guidance and references for oil and gas exploration.

Key words: Kunbei fault terrace belt, fault characteristic, forming mechanism, tectonic simulation experiment, maximum shear stress, oil and gas enrichment