Abstract: An in-situ stress analysis method is introduced to understand the reason for increase of water-breakthrough wells and the mechanism of mismatch of gas-water contact rising at different structural positions. After the establishment of a 3D dynamic in-situ stress field model, shear stress and effective normal stress on the surfaces of faults and fractures are extracted, variation of shear stress to effective normal stress ratio is calculated, mechanical activity performances of faults and fractures during stress field evolution are evaluated, by which the corresponding relation with water-breakthrough in gas production wells could be found and the mechanism of water-breakthrough in them could be clearly understood. . The study shows that the enhancement of fault and fracture activities during the dynamic change process of in-situ stress is the main reason for water production in the gas field. Additionally, the differences of mechanical activity performances of faults and fractures at different structural positions result in the mismatch of gas-water contact rising at different structural positions