Relationship Between Present Tectonic Stress Field and Natural Gas Distribution in Kuqa Depression,Tarim Basin

The present plane and sectional tectonic stresses were recovered by finite element numerical simulation,their distribution characteristics were summarized,and the relationship between the tectonic stress and the natural gas distribution was analyzed.The results show that in plane,the distribution of maximum principal stress of the sub-salt reservoir in different structural zones is not uniform and characterized by bigger stress in the north than in the south,roughly band-distributing toward near E-W,in the northern part with serious structural compression formed many low-stress areas;in cross section,the maximum principal stress is smaller at the territorial gypsum-salt caprock and its overlying strata,and bigger at the sub-salt strata;and the maximum principal stresses of the Triassic and Jurassic source rocks are generally bigger than that of overlying Cretaceous reservoir.The relative low-stress areas are formed in Kela faulted anticlines and fault blocks in Kelasu structural belt with strong tectonic compression,anticlinal apex and the side of faulted anticline in the upper close to the fault of Keshen zone.The natural gas pools discovered in Kuqa depression up to now are located at the relatively low areas of maximum principal stress.