川东北元坝西部须二段—须三段沉积相及其对储层控制作用  

Sedimentary Facies and Its Controls on the Reservoir of Xu-2-Xu-3 Member in the Western Yuanba,Northeast Sichuan Basin

作　　者：王爱 肖开华[1] 刘忠群 黄彦庆[1] 乔大伟 WANG Ai;XIAO Kaihua;LIU Zhongqun;HUANG Yanqing;QIAO Dawei(Petroleum Exploration and Production Research Institute,SINOPEC,Beijing 100083,China)

机构地区：[1]中国石化石油勘探开发研究院,北京100083

出　　处：《现代地质》2024年第2期350-361,共12页Geoscience

基　　金：中国石油化工股份有限公司科技部项目(P19012-2,P23130)。

摘　　要：川东北元坝西部须二段—须三段是重要的油气产层。本文利用钻井岩心、测井资料和三维地震资料对川东北元坝西部上三叠统须二段—须三段沉积相类型、沉积特征、沉积模式及其对储层发育控制作用开展详细的研究,以指导该地区的油气勘探部署。结果表明,川东北元坝西部须二段—须三段主要为辫状河三角洲相和湖泊相沉积,能够识别出三角洲平原、三角洲前缘、前三角洲和浅湖4种亚相,可进一步划分出9种微相。须二段—须三段沉积时期发育两种沉积模式,须二段为缓坡型宽河道辫状河三角洲沉积模式,主要发育宽河道,砂体叠置连片;须三段为陡坡型窄河道辫状河三角洲沉积模式,主要发育窄河道,砂体沿河道呈条带状分布。须二段主要发育中粒长石岩屑砂岩和中粒石英砂岩两种有利储集岩类型,主要分布于三角洲前缘水下分流河道砂体中;须三段发育中粗粒钙屑砂岩和砂质细砾岩两种有利储集岩类型,主要分布于三角洲平原辫状河道—三角洲前缘水下分流河道过渡带砂体中。缓坡型宽河道辫状河三角洲中发育的中粒长石岩屑砂岩和中粒石英砂岩储层物性和孔隙结构明显好于陡坡型窄河道辫状河三角洲中发育的中粗粒钙屑砂岩和砂质细砾岩。The Upper Triassic Xu-2-Xu-3 Member in the western Yuanba of Northeast Sichuan is an important oil and gas reservoir.In this study,we used drilling cores,logging data,and 3D seismic data to study the sedimentary facies,sedimentary characteristics,depositional models,and their effects on the reservoir development of the Upper Triassic Xu-2-Xu-3 Members,as to guide the deployment of oil and gas exploration in the region.The results show that Xu-2-Xu-3 Members are mainly braided river delta facies and lacustrine facies.Four subfacies have been recognized,as delta plain,delta,front delta,and coastal shallow lake,which can be further divided into 9 microphases.Two depositional models were developed during the depositional period of Xu-2-Xu-3 Member.Xu-2 Member shows a model of gentle slope wide channel braided river delta deposition,and mainly develops wide river channels with overlapping sand bodies.Xu-3 Member shows a model of steep slope narrow channel braided river delta deposition,and mainly develops narrow river channels,and the sand bodies are distributed as strips along the river channel.Xu-2 Member mainly develops two favorable reservoir rock types,medium feldspar sandstone and medium-grained quartz sandstone.Xu-3 Member also develops two favorable reservoir rock types,medium-coarse calcareous sandstone and fine sandy conglomerate.The high-quality reservoirs of Xu-2 Member are mainly distributed in the sand bodies of the underwater distributary channel of the delta front.The high-quality reservoirs of Xu-3 Member are mainly distributed in the sand bodies of the braided channel-delta front of the underwater distributary channel transition zone in the delta plain.The physical properties and pore structure of feldspar sandstone and quartz sandstone are significantly better developed than those of the calcareous sandstone and sandy conglomerate.

关 键 词：辫状河三角洲 沉积模式 优质储层 须家河组 川东北地区 

分 类 号：P618.13[天文地球—矿床学] P534.41[天文地球—地质学]