渝西地区须家河组辫状河三角洲沉积特征及演化模式  

Sedimentary characteristics and evolution of braided river delta of the Xujiahe Formation in Western Chongqing Area

作　　者：王欣[1] 陈龙 庹聪 刘建平 罗龙 高儇博 王濡岳 汪飒黎 吴永宏 彭文杙 余信 魏倩倩 谭先锋 WANG Xin;CHEN Long;TUO Cong;LIU Jianping;LUO Long;GAO Xuanbo;WANG Ruyue;WANG Sali;WU Yonghong;PENG Wenyi;YU Xin;WEI Qianqian;TAN Xianfeng(Chongqing Gas District,PetroChina Southwest Oil&Gasfield Company,Chongqing 401120,China;School of Petroleum Engineering,Chongqing University of Science and Technology,Chongqing 401331,China;Chongqing Key Laboratory of Complex Oil and Gas Exploration and Development,Chongqing 401331,China;Petroleum Exploration and Production Research Institute,SINOPEC,Beijing 102206 China)

机构地区：[1]中国石油西南油气田分公司重庆气矿,重庆401120 [2]重庆科技大学石油与天然气工程学院,重庆401331 [3]复杂油气田勘探开发重庆市重点实验室,重庆401331 [4]中国石油化工股份有限公司石油勘探开发研究院,北京102206

出　　处：《东北石油大学学报》2024年第6期81-97,108,I0006,I0007,共20页Journal of Northeast Petroleum University

基　　金：国家自然科学基金项目(42072140);国家自然科学基金项目(42102133);国家自然科学基金项目(42202170);重庆市自然科学基金项目(CSTB2022NSCQ-JQX0031);重庆市自然科学基金项目(CSTB2022NSCQ-MSX1166);重庆市自然科学基金项目(CSTC2021JCYJ-MSXMX0455);重庆市教委科技重大项目(KJZD-M202101502);重庆市教委科学技术研究项目(KJQN202201511)。

摘　　要：基于渝西地区须家河组钻测井、岩心、野外及地震资料,采用地层对比、沉积相分析及地震属性刻画等方法,研究须家河组沉积特征及演化模式。结果表明:渝西地区须家河组为发育于盆缘斜坡部位的辫状河三角洲沉积,发育辫状河三角洲平原辫流河道、越岸沉积、前缘水下分流河道、河口坝和远砂坝等沉积微相,湖泊相分布相对局限;沉积演化受温暖湿润—炎热干燥古气候波动影响下的湖平面变化及可容空间变化和沉积物供给的相对关系(A/S比值)控制,须三、须五段沉积时期,气候温暖湿润,湖盆水体加深,A/S比值增大,区内主要发育辫状河三角洲前缘沉积,须四、须六段沉积时期,气候炎热,蒸发量增大,湖盆变浅,A/S比值减小,以发育辫状河三角洲平原为主,厚层砂体连片发育,是致密砂岩储层发育的主力层段。该结果为晚三叠世川东地区古地理格局及须家河组致密油气勘探提供依据。In order to clarify the sedimentary characteristics and evolutionary patterns of the Upper Triassic Xujiahe Formation in the Western Chongqing Area.In this study of the Xujiahe Formation in the Western Chongqing Area,based on drilling,logging,core,field and seismic data,sedimentary characteristics and evolution patterns were investigated using techniques such as stratigraphic correlation,sedimentary facies analysis,and seismic attribute characterization.The results indicate that:the Xujiahe Formation in the Western Chongqing Area mainly consists of braided river delta deposits developed on the slope of the basin margin,with sedimentary microfacies including braided river delta plain braid channel,overbank deposits,subaqueous distributary channels,river mouth bars and distal sand bars,and a relatively limited distribution of lacustrine facies;the sedimentary evolution of the Xujiahe Formation in the Western Chongqing Area is controlled by lake level changes and A/S ratio fluctuations under warm-humid to hot-dry ancient climatic conditions,establishing an evolution model for braided river deltas in the region;during the deposition of the Xujiahe Formation,the climate was warm and humid in the XuⅢand XuⅤstages,with deepening lake water and increasing A/S ratio,mainly developing front deposits of braided river deltas in the area;in the XuⅣand XuⅥstages,the climate was hot,with increased evaporation,shallowing lake basin,and decreasing A/S ratio,primarily developing delta plain of braided river deltas,during which thick sand bodies were continuously developed,forming the main reservoir intervals for tight sandstones in the area.The research results provide a theoretical basis for understanding the Late Triassic paleogeography of the Eastern Sichuan Area and the exploration of tight oil and gas in the Xujiahe Formation in the study area.

关 键 词：辫状河三角洲 致密砂岩 沉积演化 须家河组 四川盆地 渝西地区 

分 类 号：P618.13[天文地球—矿床学] TE122.2[天文地球—地质学]