塔里木盆地库车坳陷中生代原型盆地性状及其石油地质意义  

Characteristics of Mesozoic prototype basin in the Kuqa depression of Tarim basin and its petroleum geological significance

作　　者：吴超 孙晶[2] 章国威 赵天天 程旺明 漆家福[2] WU Chao;SUN Jing;ZHANG Guowei;ZHAO Tiantian;CHENG Wangming;QI Jiafu(R&D Center for Ultra-deep Complex Reservoir Exploration and Development,CNPC,Korla,Xinjiang 841000,China;State Key Laboratory of Petrolem Resources and Prospecting,China University of Petroleum,Beijing 102249,China;Engineering Research Center for Ultra-deep Complex Reservoir Exploration and Development,Xinjiang Uygur Autonomous Region,Korla,Xinjiang 841000,China;Xinjiang Key Laboratory of Ultra-deep Oil and Gas,Korla,Xinjiang 841000,China)

机构地区：[1]中国石油天然气集团有限公司超深层复杂油气藏勘探开发技术研发中心,新疆库尔勒841000 [2]中国石油大学(北京)地球科学学院,北京102249 [3]新疆维吾尔自治区超深层复杂油气藏勘探开发工程研究中心,新疆库尔勒841000 [4]新疆超深油气重点实验室,新疆库尔勒841000

出　　处：《地质学报》2024年第12期3715-3734,共20页Acta Geologica Sinica

基　　金：中国石油天然气集团有限公司科技项目(编号2023ZZ14YJ02);中国石油天然气股份有限公司科技专项(编号2022KT0201);国家自然科学基金项目(编号42072060)联合资助的成果。

摘　　要：塔里木盆地北部边缘的库车坳陷充填了巨厚的中生界碎屑岩沉积地层(最大残留厚度可达6000 m以上),其中三叠系、侏罗系包含的多个泥岩、含煤泥岩层被认为是库车坳陷的主力烃源岩层。受地表条件复杂、地下构造变形复杂等因素影响,基于地震资料解释的中生界分布一直不甚清楚,中生代原型盆地性状的认识也有很大的分歧。近几年在库车坳陷实施了大连片三维地震资料的统层解释。结果表明中生界下部发育有大量控制三叠系、甚至下侏罗统沉积厚度分布的同生正断层。这些正断层的发现,暗示库车坳陷早中生代原型盆地可能具有伸展或走滑伸展断陷盆地性质。本文基于三维地震资料解释成果分析了库车坳陷中生代盆地结构及后期构造演化过程,认为早中生代同生正断层在晚中生代、新生代区域挤压及新天山构造隆升作用下发生了不同程度的改造(反转),导致形成复杂的冲断构造变形,一些区段的中生界烃源岩成为后期逆冲褶皱变形的局部滑脱层,而另一些区段则被后期逆冲断层掩覆成为断陷正反转构造的“死带”。这一新的构造解释模型不仅可以合理地解释库车坳陷油气聚集的分区、分段差异性,也进一步明确了深层油气勘探领域及需要研究的地质问题。库车坳陷那些位于正反转断层(包括拆离断层)下盘“死带”中的三叠系、侏罗系烃源岩的存在为深层油气成藏奠定了物质基础。The Kuqa depression,located at the northern edge of the Tarim basin,is filled with extremely thick Mesozoic clastic sedimentary strata,with a maximum residual thickness exceeding 6000 m.The mudstone and coal-bearing rocks contained in the Triassic and Jurassic formations are considered the primary hydrocarbon source rocks in the depression.Due to the complex surface conditions and underground tectonic deformation,the distribution of the Mesozoic strata in the Kuqa depression revealed by seismic data is not clear.This led to significant differences in understanding the characteristics of the Mesozoic prototype basin.Recent interpretations of extensive 3D seismic datasets acquired across the Kuqa depression have identified a large number of deep-seated normal faults in the lower Mesozoic strata.These faults control the distribution of sedimentary thickness in the Triassic and even the Lower Jurassic.The discovery of these deep normal faults,which controlled the early Mesozoic sedimentation,indicates that the early Mesozoic Kuqa depression basin should be an extensional or strike-slip extensional faultcontrolled basin.This paper,based on the results of 3D seismic data interpretation,analyzes the structure of the Mesozoic basin in the Kuqa depression and its subsequent tectonic evolution.The results show that the late Mesozoic basin was an extensional basin superimposed on the Hercynian orogenic wedge of the southern Tianshan.Under the influence of late Mesozoic and Cenozoic regional compressions and the uplift of the new Tianshan,the early Mesozoic normal faults were reconstructed or inversed to different degrees,resulting in the formation of complex contractional structural deformation.The Mesozoic source rocks in some areas became the local detachment layer of late thrust fold deformation,while others were overthrust to become the“dead zone”under the detachment fault in the deeper fault depression.This new structural interpretation model for the Early Mesozoic basin not only explains the variations in oil and

关 键 词：中生界 正反转断层 分层滑脱构造 烃源岩分布 库车坳陷 

分 类 号：P618.13[天文地球—矿床学]