中哈边境吉木乃—斋桑盆地二叠系油气成藏要素  

Permian hydrocarbon accumulation factors in the Jimunai—Zaysan basin,China-Kazakhstan border

作　　者：冯杨伟 任艳[1] 屈红军 王云[3] 姜亭[4] FENG Yangwei;REN Yan;QU Hongjun;WANG Yun;JIANG Ting(School of Geography Science and Tourism,Nanyang Normal University,Nanyang,Henan 473061,China;School of Earth Sciences,East China University of Technology,Nanchang,Jiangxi 330013,China;Department of Geology,Northwest University,Xi'an,Shaanxi 710069,China;Xi'an Center of Geological Survey,CGS,Xi'an,Shaanxi 710054,China)

机构地区：[1]南阳师范学院地理科学与旅游学院,河南南阳473061 [2]东华理工大学地球科学学院,江西南昌330013 [3]西北大学地质学系,陕西西安710069 [4]中国地质调查局西安地质调查中心,陕西西安710054

出　　处：《地质学报》2021年第6期1935-1948,共14页Acta Geologica Sinica

基　　金：国家科技重大专项“大型油气田及煤层气开发”(编号2016ZX05026007);江西省自然科学基金资助项目(编号20202BABL211019);山东省沉积成矿作用与沉积矿产重点实验室开放基金(暨刘宝珺地学青年科学基金)(编号DMSM2019008)联合资助的成果。

摘　　要：吉木乃—斋桑盆地是古亚洲洋构造域西段勘探程度较低的重要二叠系含油气盆地,油气聚集成藏研究尚浅。基于区域地质、地质露头、钻井、地震、分析化验等资料,开展生、储、盖、圈、运、保油气地质条件分析,研究生烃过程、排烃动力和成藏动力与方式,制作含油气系统事件表,探讨油气成藏过程与油气成藏模式。吉木乃—斋桑盆地发育两套主力二叠系烃源岩:①下二叠统卡拉岗组/阿坎赛组浅湖相暗色泥岩,主要分布在盆地南部山前地区,发育于淡水湖泊轻微缺氧环境,TOC含量为0.936%;S_(1)+S_(2)为0.086mg/g,Ⅱ2-Ⅲ型干酪根,Ro为1.54%,成熟—过成熟阶段;②上二叠统麦恰特组深湖-半深湖黑色油页岩、泥岩,主要分布在斋桑坳陷中部地区,发育于咸水、强还原的环境,Ⅰ型干酪根,Ro为0.68%,孢粉色变指数为2.83,处于刚进入生油窗的低成熟阶段。储集层主要为二叠系砂岩和砾岩,二叠系麦恰特组与阿考尔康组泥页岩为重要的盖层。圈闭以岩性、背斜、断鼻、断块、地垒等形式为主,发育正断层、岩浆底辟构造油气短距离垂向运移和不整合面油气长距离侧向运移两类油气运移通道。主力烃源岩经历多次生排烃过程,早侏罗世达到生油高峰,古近纪达到生气高峰。油在异常过剩压力驱动下近距离进入二叠系岩性圈闭中成藏;部分通过断裂、岩浆底辟等通道垂向短距离运移,进入断背斜、底辟构造等圈闭中富集成藏;气经长距离侧向运移在古近系与下伏地层间的不整合面附近富集成藏。The Jimunai-Zaysan basin is an important Permian petroliferous basin with low degree of exploration in the western part of the paleo-Asian Ocean structural domain,with limited study of hydrocarbon accumulation.Based on regional geology,geological outcrops,core,lab tests,and seismic data,the petroleum geological conditions of generation,storage,cover,circle,transportation and preservation were analyzed.From this,the hydrocarbon generation process,driving forces for expulsion,reservoir forming power and mode were studied,the event chart of petroleum system was drawn,the hydrocarbon accumulation process with its model were comprehensively analyzed and summarized.Two sets of main Permian source rocks are developed in the Jimunai—Zaysan basin:①Lower Permian shallow lake dark mudstones in the Kalagang Formation or theАкансайскаяFormation is one set of source rocks,which is mainly distributed in the piedmont area in the south of basin,and developed in a fresh water lake with slight anoxic environment.The content of TOC is 0.936%,S_(1)+S_(2)is 0.086mg/g,kerogen type isⅡ2-Ⅲ,Rois 1.54%,and organic matter are basically at maturity&over maturity stage.②Upper Permian semideep to deep lake dark oil shale and the mudstone Maichat Formation is another set of source rocks,which mainly distributed in the central part of the Zaysan depression,and developed in saline and strongly reducing environment.Kerogen type isⅠ,Rois 0.68%,the color change index of sporopollen is 2.83,organic matter is in the low mature stage of oil generation window.The reservoir mainly consists of Permian sandstone and conglomerate.The shale of the Maichat Formation and the Kalagang Formation are important caprocks.The traps are mainly in the form of lithology,anticline,fault nose,fault block and horst.There were two types of oil and gas migration pathways,one was normal fault and magmatic cleavage short distance vertical migration pathway,the other was unconformity surface long distance lateral migration pathway.The main source rocks h

关 键 词：中哈边境 二叠系 斋桑坳陷 吉木乃 麦恰特组 卡拉岗组 油气聚集成藏 

分 类 号：P618.13[天文地球—矿床学]