鄂东X区8号煤层构造演化及控藏作用分析  

Analysis of Structural Formation Evolution and Reservoir Control Effect of No.8 Coal Seam in X Area,Eastern Ordos Basin

作　　者：郭晓娇 刘之的 刘桂珍[1,2] 胡建波 王成旺[4,5] 金鑫 GUO Xiao-jiao;LIU Zhi-di;LIU Gui-zhen;HU Jian-bo;WANG Cheng-wang;JIN Xin(School of Earth Science and Engineering,Xi'an Shiyou University,Xi'an 710065,China;Shaanxi Provincial Key Laboratory of Oil and Gas Reservoir Geology,Xi'an Shiyou University,Xi'an 710065,China;College of Resources,China University of Geosciences(Wuhan),Wuhan 430074,China;PetroChina Coalbed Methane Co.,Ltd.,Beijing 100028,China;Research Institute of Engineering Technology,PetroChina Coalbed Methane Co.,Ltd.,Xi'an 710082,China)

机构地区：[1]西安石油大学地球科学与工程学院,西安710065 [2]西安石油大学陕西省油气成藏地质学重点实验室,西安710065 [3]中国地质大学(武汉)资源学院,武汉430074 [4]中石油煤层气有限责任公司,北京100028 [5]中石油煤层气有限责任公司工程技术研究院,西安710082

出　　处：《科学技术与工程》2024年第29期12431-12441,共11页Science Technology and Engineering

基　　金：西安石油大学硕士研究生创新与实践能力培养计划(YCS23113044);陕西省重点研发计划(2022GY-130);中石油煤层气有限责任公司科技重大专项(2021-KJ-04)。

摘　　要：鄂尔多斯盆地东部X区本溪组煤层气区域性富集,生产资料显示其成因与构造有一定关联,但其缺乏明确的富集规律与地质理论。鉴于此,分析X区煤层构造演化历程,对比井上热演化史及生烃史分析成果,以期明确构造演化对深部煤层气富集的控制作用。结果表明:本溪组煤层生烃主要发生在晚二叠-早三叠世与晚侏罗-早白垩世两个阶段,其中晚侏罗-早白垩世大量生烃。两次生烃期煤层顶部古构造对于煤层气的富集、高产均具有一定的控制作用,且第二次生烃期古构造控藏作用明显,煤层气主要在煤层顶部古构造低洼处富集、高产;工区受多期构造运动影响,8号煤层气主要富集在煤层顶部现今构造缓坡段,陡坡段极少或者不富藏,且煤层顶部现今构造高度相对越低,产气量表现为上升趋势;综合构造演化史认为深部煤层气的富集、高产主要受第二次生烃期古构造洼地和后期抬升作用控制。研究结果为古构造源内控藏理论及深层煤层气富集、高产成因提供了一定的地质理论依据。The regional enrichment of coalbed methane in the Benxi Formation of the X region in the eastern Ordos Basin is evident from production data,and it is believed to be correlated with tectonic structures.However,a clear comprehension of the enrichment patterns and geological theories remains unclear.To address this,an analysis of the tectonic evolution of the coal seams in the X region was conducted.This analysis compared the thermal evolution history and hydrocarbon generation history obtained from wells,aiming to clarify the controlling role of tectonic evolution on the enrichment of deep coalbed methane.The results indicates that the hydrocarbon generation in the coal seams of the Benxi Formation primarily occurred during two periods:the late Permian-early Triassic and the late Jurassic-early Cretaceous,with significant generation during the latter.During these periods,the ancient structures overlying the coal seams exerted a controlling influence on the enrichment and high production of coalbed methane,with a more pronounced effect observed during the second period.In particular,methane accumulated primarily in the low-lying areas of these structures.The study area is affected by multiple tectonic movements,leading to a No.8 preferential concentration of coalbed methane in the gently sloping sections of the current structures overlying the coal seams.Conversely,steep slope sections exhibit minimal or no enrichment.Furthermore,a decrease in the structural height overlying the coal seams is associated with an increasing trend in gas production.A comprehensive analysis of the tectonic evolution history suggests that the enrichment and high production of deep coalbed methane are primarily controlled by ancient structural depressions formed during the second hydrocarbon generation period and subsequent uplift processes.These findings provide a solid geological theoretical basis for understanding the internal control mechanisms of ancient structures on reservoirs and the genesis of deep coalbed methane enrichment and

关 键 词：鄂尔多斯盆地 深部煤层气 构造演化 古构造 控藏分析 

分 类 号：P542.5[天文地球—构造地质学]