鄂尔多斯盆地东南部上古生界煤层分布特征  

Geophysical identification and distribution of Upper Paleozoic coals in southeastern Ordos Basin

作　　者：吴疆[1] 关蕴文 蒲仁海[2] 高小平[3] WU Jiang;GUAN Yunwen;PU Renhai;GAO Xiaoping(Sinopec Petroleum Exploration and Production Research Institute,Beijing 100083,China;Department of Geology/State Key Laboratory of Continental Dynamics,Northwest University,Xi’an 710069,China;Yanchang Petroleum Group Exploration Company,Yan’an 716000,China)

机构地区：[1]中国石化石油勘探开发研究院,北京100083 [2]西北大学地质学系/大陆动力学国家重点实验室,陕西西安710069 [3]延长石油集团油气勘探公司,陕西延安716000

出　　处：《西北大学学报（自然科学版）》2023年第5期830-842,共13页Journal of Northwest University（Natural Science Edition）

基　　金：国家自然科学重大基金项目(41390151)。

摘　　要：根据岩心、测井、地震资料综合分析鄂尔多斯盆地东南部煤层识别方法、厚度变化及其与古地貌和沉积相关系。研究发现,该区在山西组下段和本溪-太原组发育两套较厚煤层,它们具有低自然伽马、低密度、高电阻率和高时差测井特征,在地震剖面上形成半个周期的上谷下峰特强振幅反射。两套煤层累计厚度1~10 m,平均累厚2.4 m,单层煤最厚5.5 m。单层厚度大于2 m的煤层面积约2500 km 2,煤层埋深一般2500~3000 m。研究认为,本溪-太原组厚煤层主要分布在近源的、具有下切成因的奥陶系古岩溶凹地,而无下切的、远源的奥陶系古岩溶凹地为同时代或近时代的灰岩沉积;上古生界的煤层与分流河道砂岩在平面上的分布具互补关系。Based on core,logging,and seismic data,a comprehensive analysis was conducted on the identification methods of coal seams,thickness changes,and their relationship with paleogeomorphology and sedimentary facies in the southeastern part of the Ordos Basin.The lower part of Shanxi Fm and the upper part of Taiyuan Fm in the southeastern part of the basin characterize low natural gamma ray,low density,high resistivity and high sonic logging values.As the coal velocity is very low and alternates with high-velocity Taiyuan Fm and Ordovician limestones,the two sets of coalsbelow and above Taiyuan limestonesform an extremely-strong amplitude reflection on the seismic profile.The two sets of coals are 1~10 m thick cumulatively,average 2.4 m,with 4 m as the maximum induvial thickness.The coal seam with an individual layer thicker than 2 m covers an area of about 2500 km 2,and the buried depth of the coal seam range from 2500 to 3000 m.Research has shown that the thick coal seams of Taiyuan Fm are mainly distributed proximally in the Ordovician paleokarst depression with incised origin,while the Ordovician paleokarst depression without incised origin was deposited by distal coeval limestone rocks.There is a complementary relationship between the coal seams and the thickening zone of distributary channel sandstone for the Shanxi Fm.

关 键 词：煤层分布 测井与地震响应 古地貌 沉积相 

分 类 号：P618.13[天文地球—矿床学]