鄂尔多斯盆地东北部石炭系本溪组铝土岩储层特征及形成机理  

CHARACTERISTICS AND FORMATION MECHANISM OF CARBONIFEROUS BENXI FORMATION BAUXITE RESERVOIR IN NORTHEASTERN ORDOS BASIN

作　　者：彭帅杰 赵俊兴[1,3] 张佳超 李宁 雷迅[4] 李文涛 胡潇 魏克颖 解古巍 徐潇[1] 张林林 PENG Shuaijie;ZHAO Junxing;ZHANG Jiachao;LI Ning;LEI Xun;LI Wentao;HU Xiao;WEI Keying;XIE Guwei;XU Xiao;ZHANG Linlin(Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu,Sichuan 610059,China;The Third Gas Production Plant,petrochina Changqing Oilfield Com pany,Wurin Banner,Inner Mon-golia500063,China;National Engineering Laboratory for Exploration and Development of Low Permeability Oil and Gas Fields,Xi'an,Shaanri710018,China;Natural Gas Evaluation Project Department,PetroChina Changqing Oilfield Company,Qingyang,Gansu 745099,China)

机构地区：[1]成都理工大学沉积地质研究院,四川成都610059 [2]中国石油长庆油田分公司第三采气厂,内蒙古乌审旗500063 [3]低渗透油气田勘探开发国家工程实验室,陕西西安710018 [4]中国石油长庆油田分公司天然气评价项目部,甘肃庆阳745099

出　　处：《矿物岩石》2024年第3期192-205,共14页Mineralogy and Petrology

摘　　要：近年来,在鄂尔多斯盆地西南部陇东地区石炭系太原组的铝土岩中首次取得天然气藏勘探突破,铝土岩型气藏成为找气新领域,盆地东北部石炭系本溪组铝土岩发育,存在一定勘探潜力。本次研究通过岩石铸体薄片观察、扫描电镜、能谱分析、全岩及黏土矿物X衍射、物性分析、微量元素分析等手段,对盆地东北部本溪组铝土岩的储层特征及形成机理开展研究,结果表明:①铝土岩沉积序列自下而上为底部铁铝质铝土岩及铝土质泥岩、中部含高铝质铝土岩及铝土质泥岩、顶部铝土质泥岩构成;②铝土岩结构主要为豆鲕状、多孔团块状、致密状、碎屑角砾状等,铝土岩矿物成分主要为铝铁质矿物、黏土矿物、钛质矿物、微量矿物等;③研究区铝土岩储层发育良好,储集空间类型主要为蜂窝状溶蚀孔、晶间孔等,孔隙度介于0.3%~11.6%,平均值为2.86%,渗透率介于(0.002~21.400)×10^(-3)μm^(2),物性良好,具一定成储潜力,可动流体饱和度平均大于45%,孔隙连通性好;④盆地东北部本溪组铝土岩储层的控制因素为:前期构造抬升运动提供成岩物质来源、封闭-半封闭的潮坪-滨岸环境提供成岩环境、潜坑-阶地微古地貌控制储层品质,为主要的勘探有利区、后期有机酸对储层孔隙进一步改造。本次的研究成果为盆地东北部地区铝土岩系气藏新领域勘探提供了重要参考。In recent years,significant strides have been made in gas exploration within the bauxite depos-its of the Carboniferous Taiyuan Formation in the Longdong area of the southwest Ordos Basin,marking a new frontier in gas exploration.Research indicates that there is potential for natural gas exploration in the Carboniferous Benxi Formation bauxite in the northeastern Ordos Basin.This study investigates the reser-voir characteristics and formation mechanisms of the Benxi Formation bauxite in the northeastern Ordos Basin through methods including optical thin section observation,scanning electron microscopy,energy spectrum analysis,whole rock and clay mineral X-ray diffraction,physical property analysis,and trace el-ement analysis.Research findings indicate the sedimentary sequence of Carboniferous Benxi Formation bauxite comprises ferritic bauxite and aluminous mudstone at the base,transitioning to high alumina baux-ite and alumina mudstone in the middle,and concluding with alumina mudstone at the top.The bauxite rocks predominantly exhibit structures such as pisoloidal,porous massive,compact,and clastic breccia-ted.They are composed primarily of alumino-ferric minerals,clay minerals,titanium minerals,and trace minerals.In terms of reservoir characteristics,the bauxite reservoirs in the study area are notably well-de-veloped,featuring honeycomb-like dissolution pores and intercrystalline pores as the primary reservoir types.Porosity ranges from 0.3%to 11.6%(average of 2.86%),and permeability spans from 0.002 to 21.400×10^(-3)μm^(2).These reservoirs exhibit favorable physical properties with good pore connectivity.On average,mobile fluid saturation exceeds 45%,suggesting significant reservoir potential.The controlling factors influencing the Benxi Formation bauxite reservoir in the northeast basin include early tectonic uplift movements providing diagenetic materials,an enclosed to semi-enclosed tidal flat-shore environment foste-ring diagenetic processes,and micro-paleotopography of buried pit-terraces influencing r

关 键 词：鄂尔多斯盆地 铝土岩储层 本溪组 沉积环境 古地貌 

分 类 号：TE122.1[石油与天然气工程—油气勘探]