砂岩高岭石赋存状态、成因机制及其对物性的影响——以酒泉盆地营尔凹陷下沟组为例  

Occurrences and formation mechanisms of kaolinite cements in sandstones and their effects on sandstone property:taking Xiagou Formation in Yinger Depression,Jiuquan Basin as an example

作　　者：周晓峰[1,2,3] 唐海忠 魏军 周在华 肖文华 李景 于均民 ZHOU Xiaofeng;TANG Haizhong;WEI Jun;ZHOU Zaihua;XIAO Wenhua;LI Jing;YU Junmin(School of Petroleum Engineering,China University of Petroleum(Beijing),Beijing 102249,China;MOE Key Laboratory of Petroleum Engineering,China University of Petroleum (Beijing),Beijing 102249,China;State Key Laboratory of Petroleum Resources and Engineers,Beijing 102249,China;Exploration and Development Research Institute,PetroChina Yumen Oilfield Company,Jiuquan,Gansu 735019,China)

机构地区：[1]中国石油大学(北京)石油工程学院,北京102249 [2]中国石油大学(北京)石油工程教育部重点实验室,北京102249 [3]油气资源与工程国家重点实验室,北京102249 [4]中国石油玉门油田分公司勘探开发研究院,甘肃酒泉735019

出　　处：《东北石油大学学报》2019年第1期40-49,59,I0003-I0004,共12页Journal of Northeast Petroleum University

基　　金：中国石油天然气股份有限公司重大科技专项(2018D-0704)

摘　　要：酒泉盆地营尔凹陷下白垩统下沟组砂岩中发现高岭石以黏土膜和充填孔隙的赋存方式共存的现象。利用铸体薄片和扫描电镜方法,观察高岭石的赋存状态,研究成因机制及其对砂岩物性的影响。结果表明:高岭石黏土膜是由砂岩在表生成岩阶段遭受大气水淋滤所致,形成时间为晚白垩世;新近纪末期以来的中成岩阶段,砂岩具有强应力敏感而使流体流动能力降低,有机酸溶蚀长石和火山岩岩屑,产生的铝、硅质流体在附近的粒间孔隙中形成充填孔隙高岭石。高岭石黏土膜并不抑制次生石英加大,当有足够浓度的SiO2流体进入孔隙时,次生石英加大沉淀在高岭石黏土膜上;长石和火山岩岩屑溶蚀是砂岩孔隙度增加的过程,充填孔隙高岭石发育是优质储层的标志。该结果为营尔凹陷下沟组寻找充填孔隙高岭石发育的砂岩储层提供指导。Coexistence of kaolinite coat and pore-filling kaolinite has first been discovered in Low Cretaceous Xiagou Formation sandstones in Yinger Depression,Jiuquan Basin.By casting slice and scanning electron microscope the occurrences of kaolinite cements were observed,in order to study their formation mechanisms and effects on sandstone property.The result shows that the kaolinite coat formed with meteoric water leaching the sandstones during the Late Cretaceous exodiagenesis stage.Since the end of Neogene,the Xiagou Formation sandstones have entered upon the middle diagenesis stage.Because of the strong stress sensitivity of the sandstones causing the decrease of the fluid mobility,aluminium and siliceous fluids that come from feldspar and igneous rock particles dissolved by organic acid fluids deposit and form the pore-filling kaolinite in the nearby intergranular pores.The kaolinite coat hardly inhibited the quartz overgrowth.When SiO 2 fluid was enough in pores,the quartz overgrowth formed and settled on this coat.The formation of the pore-filling kaolinite by the dissolution of feldspar and igneous rock particles is a process that improves the sandstone porosity,so the pore-filling kaolinite is a sign of high quality reservoir.This result provides some guidance for searching for sandstone reservoirs with pore-filled kaolinite in Xiagou Formation of Yinger Depression.

关 键 词：高岭石黏土膜 充填孔隙高岭石 下沟组 营尔凹陷 酒泉盆地 

分 类 号：TE122.1[石油与天然气工程—油气勘探]