塔里木盆地库车坳陷北部油气资源丰富,但由于受研究区地表和地下构造双重复杂特征及巨厚膏盐层的影响,其深层地震资料的成像质量与精度不理想,准确研究盐下构造形态存在较大难度.为此,基于前人的研究成果,根据最新的三维叠前深度偏移地震剖面,建立了克拉苏构造带盐下构造层的初始构造模型,并运用面积深度法分析了盐下构造层的变形特征和变形机制.结果表明:①盐下层构造的分布以克拉苏断裂为界线,断裂以北主要发育基底卷入的高角度逆冲构造,而断裂以南则主要发育滑脱构造;②克拉苏断裂以南区域滑脱面的位置介于8.01～10.23 km深度,推测该滑脱层为三叠系与下伏基底之间的不整合面;③博孜区域的滑脱距离为7.49 km,大北区域的滑脱距离为14.35 km,克深5区域的滑脱距离为12.46 km,克深1-2区域的滑脱距离则为16.32 km,该区盐下构造层的滑脱距离呈现出自西向东逐渐增加的趋势,表明从西向东构造变形越来越强烈.

基于地表露头调查、地震资料解释、钻井及与盐相关的构造样式分析,对库车坳陷中部构造变形特征进行研究。结果表明:库车坳陷中部具有南北分带、东西分段、垂向分层的变形特征。以库姆格列木群膏盐岩为界可以分为盐上构造层、盐构造层、盐下构造层及基底构造层4层结构。该区域主要发育收缩构造样式及盐构造样式,盐上构造层、盐构造层及盐下构造层的构造样式及分布具有明显差异。盐上层主要发育逆冲断层及褶皱,盐岩层则以盐流动构造样式为主,盐下层则发育逆冲叠瓦断层等大规模推覆构造。研究区具有明显的分段变形特征,可划分为博孜—却勒构造段、大北—西秋构造段、克深—西秋构造段、克拉3—东秋构造段,其差异性主要表现为地表线性褶皱带分布、盐构造样式、盐下构造变形的差异。区域构造演化剖面研究表明库车坳陷主要经历了中生代伸展坳陷盆地（三叠纪—白垩纪）、新生代早期"挠曲"盆地（古近纪—中新世）及新生代晚期前陆盆地（上新世—第四纪）的演化过程。现今构造主要形成于库车组沉积的中晚期。

The salt layer thickness of Kuche depression varied dramatically because of the strong tectonic extrusion,and the distribution of salt layer and salt-related structure have some pattern. Based on the style of pre-salt structure,we studied the salt layer and pre-salt structure of middle Kuche depression,and divided the salt-related structures of Kuche depression into three types and five structural styles. We elaborated the block and belt characteristics of different types of salt-related structures,studied the formation mechanism of salt-related structures in middle Kuche depression,and found that the key control factor of the salt-related structures is tectonic extrusion and differential load.

DB1 gasfield is situated in the western part of Kelasu structural belt in Kuqa depression,the gas reserve in DB1 is more than 1 000×108 m3.The structural and geological conditions are very complicated,there are thick gravel areas and high mountains on the surface,evaporate salt bed developed underground.The structural styles are mainly fault-propagation folds above the salt layers and fault-bend folds under it.The research concludes that DB1 structure is complicated,in which the faults control hydrocarbon's accumulation and structural characteristics,not only influence the reservoir,but also connect to reservoir and source rock,and decide the condition of the reservoir preserved or destroyed.Above all,it is the key factor to study fault characteristics which could make us know DB1 gas field better.

DN gas fields are located in the Dongqiulitage structure belt in Kuqa depression.Currently,three gas reservoirs,DN1,DN2 and DN3,have been discovered with 3P reserves of more than 2 000×108m3 in the reservoirs.More gas are expected to be discovered.With the successful application of varying velocity mapping technology,we have estimated the DN2 gas field and discovered the DN3 gas reservoir.Interval velocity is the key factor in discovering traps.This paper discusses the method about varying velocity mapping used in estimating the DN2 gas field and discovering the DN3 gas reservoir.The good method to discover or estimate traps is that the prestack depth migration technology is used in 3D work area and the interval velocity filling is used in 2D work area.

The analysis of Early-Middle Jurassic structural and lithofacies in Kashi sag shows that the Lower-Middle Jurassic strata developed respectively in two sedimentary systems, namely Kuzigongsu-Keziletao strike-slipping pull-apart faulted-depression and piedmont faulted-depression. Both of the sedimentary systems resulted in the different features of lithology, lithofacies, sedimentary thickness and distribution. The system of strike-slipping pull-apart faulted-depression of great thickness of Jurassic is controlled by the Talaso-Ferghana fault, with high-quality source rocks made up of coal-bearing strata and deep-semideep lake mudstone. The system of piedmont faulted-depression with relative thinner thickness of Jurassic possesses good source rocks formed by locally distributed coal-measure strata in south Tianshan mountain and west Kunlun mountain. The oil and gas derived from the Lower-Middle Jurassic source rocks reach the key moments for hydrocarbon accumulation at end of Paleogene and Pliocene, respectively. It is concluded that the petroleum exploration in view of the Jurassic petroleum system should focus on the structural positions where the later structural transformation is relatively weak, or on the secondary oil-gas accumulation.

The correlation and study of Upper Carboniferous in west section of Megati slope show that two unconformities occur within the Carboniferous: one lies in major limestone between Nanzha formation of Permian and Xiaohaizi formation of Carboniferous,which is of distinct litho-electric feature and oil/gas-controlled process;the other lies at the top of Kalashayi formation of Carboniferous in west section of Mageti slope,being a large and regional unconformity.It is concluded that the latter is shaped by regression and tectonic movement in Late Carboniferous in Tarim basin.