库车坳陷的地质结构及其对大油气田的控制作用  

Geological Structure and Its Controls on Giant Oil and Gas Fields in Kuqa Depression,Tarim Basin:A Clue from New Shot Seismic Data

作　　者：何登发[1] 周新源[2] 杨海军[2] 雷刚林[2] 马玉杰[2] 

机构地区：[1]中国地质大学(北京)海相储层演化与油气富集机理教育部重点实验室,北京100083 [2]中国石油塔里木油田公司,新疆库尔勒841000

出　　处：《大地构造与成矿学》2009年第1期19-32,共14页Geotectonica et Metallogenia

基　　金：国家重点基础研究发展计划(编号:2006CB202300);国家自然科学重点基金(编号:40739906)资助

摘　　要：库车坳陷是在晚二叠世之前的古生代褶皱基底上历经晚二叠世-三叠纪的前陆盆地、侏罗-古近纪的伸展坳陷盆地和新近纪-第四纪陆内前陆盆地的演化而形成的。基底中的软弱层、侏罗系煤层和古近系库姆格列木组与新近系吉迪克组膏盐(泥)岩构成了自山前向盆地内部逐渐抬升的滑脱面,与自山前向盆地内部逐渐趋缓的地表面构成楔形体。该楔形冲断体的内部结构具有"垂向分层、横向分带与纵向分段"特点,NW向的阿瓦特-喀拉玉尔滚和NE向的库车横向构造转换带将其分割为乌什、拜城与阳霞3个构造区段。构造层发育特点决定了库车坳陷发育三叠-侏罗系的区域展布的有效烃源岩和(侏罗系、)白垩系-第三系储盖组合;分层变形特点导致盐下层形成叠瓦冲断构造组合,冲断层成为油源断层;叠瓦式的冲断层相关褶皱背斜组合导致了复式天然气聚集区带的形成,即在大北-克拉苏式的构造带上每一冲断层相关褶皱背斜带独立成藏,复合连片形成复式油气聚集(区)带,目前拜城北、克深、克拉苏背斜带已呈现这种趋势;撕裂断层则决定着构造带上具体的油气富集区段。库车坳陷油气资源丰富,地质结构特点决定了不同类型油气田分布的分区性。The Kuqa depression of Tarim basin formed on the pre-Late Permian Paleozoic folded basement and has undergone the evolution of foreland basin in Late Permian to Triassic, extensional sag basin in Jurassic to Paleogene, and rejuvenated foreland basin in Neogene to Quaternary, respectively. The weak intervals in the basement, the Jurassic coal beds, and the gypsum and salt or mud intervals of Paleogene Kumgrim Formation in the west and the Neogene Jidik Formation in the east have contributed as a whole to detaching shallowly upward from the north to the south. The detachment and the surface which dips shallowly basin-ward, constitute a typical tectonic wedge. The internal structure of the thrust wedge is characterized by the stratification in vertical, zonation horizontally, and segmentation in longitude. The N-W trending Awat-Karayuergun fault and the N-E trending Kuqa fault divide the Kuqa depression into three segments as Wushi sag, Baicheng sag, and Yangxia sag from west to east. The characters of structural layers have controlled largely the regional development of the effective source rocks in Triassic to Jurassic and the occurrence of reservoir-cap rock associations. The structural deformation with a stratification character has decided upon the formation of sub-sah imbricate structures with the thrust faults as the pathways for oil and gas. The combination of fault-related folds and the accordingly imbricate structures have resulted in the occurrence of such composite oil and gas zones or plays. For example, each fault-related folds in the Dabei-Kelasu structural belts has accumulated oil and gas separately, and then they combined together to form a larger composite gas plays. This kind of phenomenon has at present been proven partly by the Dabei gas play, the sub-Kelasu gas play and the Kelasu gas play. The tear faults or the transfer faults have controlled the enrichment in oil and gas in different blocks or segments. The Kuqa depression is a favorable area for oil and gas to accumulate. Thus, it is a pro

关 键 词：地质结构 油气成藏 复式聚集区(带) 库车坳陷 塔里木盆地 

分 类 号：P542[天文地球—构造地质学]