库车坳陷中秋构造转换带三维构造模型及成因机制分析  

Structural Model and Deformation Mechanism of the Zhongqiu Transfer Zone in Kuqa Depression

作　　者：谢会文[1] 汪伟[2] 徐振平[1] 尹宏伟[2] 罗浩渝[1] 杨庚兄 章学歧 段云江[1] XIE Huiwen;WANG Wei;XU Zhenping;YIN Hongwei;LUO Haoyu;YANG Gengxiong;ZHANG Xueqi;DUAN Yunjiang(Research Institute of Petroleum Exploration and Development,Tarim Oilfield Company,PetroChina,Korla 841000,Xinjiang,China;School of Earth Science and Engineering,Nanjing University,Nanjing 210046,Jiangsu,China)

机构地区：[1]中国石油塔里木油田公司勘探开发研究院,新疆库尔勒841000 [2]南京大学地球科学与工程学院,江苏南京210046

出　　处：《大地构造与成矿学》2022年第5期898-910,共13页Geotectonica et Metallogenia

基　　金：国家自然科学基金项目(41572187、41272227、41927802);国家油气重大专项(2017ZX005008001);中国博士后科学基金项目(2020M671432)联合资助。

摘　　要：分段变形是褶皱冲断带的典型特征之一,揭示分段变形构造转换带的变形特征与成因机制是深入解析褶皱冲断带变形机制的关键。通过典型剖面解析和三维构造模型,对库车坳陷东、西段构造转换区域的中秋构造转换带进行系统的分析。中秋构造转换带具有垂向分层变形的特征,盐上层构造差异表现为构造变形传播的距离向东减小,导致盐上层秋里塔格背斜走向角度的改变。盐下层构造差异位于盐下冲断变形构造的前缘,自西向东,盐上和盐下分层变形减弱,构造样式由盐上层滑脱变形和盐下层等距离逆冲构造向盐上和盐下层一体楔体逆冲转变。中秋构造转换带盐下层变形前缘的构造样式差异主要通过雁行排列的断层来调节,库姆格列木群膏盐层和吉迪克组膏盐层在该区域的转换是控制构造转换带的重要因素。同时差异变形的传播范围在构造转换带前缘形成压扭应力环境,使得雁行次级断裂走向为北东向。构造转换带内部雁行排列的次级断裂形成的圈闭与克拉苏构造带盐下圈闭的储盖组合模式类似,是有利的油气富集区域。但是有限的分布范围和压扭的应力环境是该区域油气勘探面临的挑战。Revealing the structural model and deformation mechanism of the transfer zone is critical for understanding the evolution of fold and thrust belt. Typical transfer zones commonly have varied structural styles along strikes. The Zhongqiu transfer zone of the Kuqa Depression has been analyzed systematically, and the 3D geometry of the transfer zone is built. The decoupling deformation above and below the salt layer exists in the Zhongqiu transfer zone. The propagation distance of deformation in the suprasalt units decreases from west to east, causing the direction rotation of the suprasalt structural strike. The changing structural style along the strike of the subsalt units occurs in the frontier of the deformation zone. Structures above and below the salt layer are apparent different in the western zone, with the suprasalt structure composed of detachment folds while the subsalt structure composed of equidistant thin-skinned thrust faults. Only one wedge structure was formed in the eastern zone which is composed of a deep thrust fault and shallow back-thrust fault. The transfer zone is associated with en echelon faults to accommodate the different structural styles along the strike, which is controlled by the distribution and efficiency of the shallow detachment. The increasing distance of deformation propagation from east to west forms a shear stress field in the transfer zone, causing the NE trending of the en echelon faults. The traps formed by the en echelon faults are favorable hydrocarbon accumulation zone, which have reservoir and caprocks similar to those of the Kelasu structure zone. In addition, the limited range and shear stress of the en echelon faults in the transfer zone should be taken into consideration in the hydrocarbon exploration.

关 键 词：库车坳陷 构造转换带 盐构造 三维构造分析 雁行断层 

分 类 号：P542[天文地球—构造地质学]