四川盆地及周缘寒武系洗象池组层序-岩相古地理演化与天然气有利勘探区带  

Sequence-based lithofacies paleogeography and favorable natural gas exploration areas of Cambrian Xixiangchi Formation in Sichuan Basin and its periphery

作　　者：文华国[1,2] 梁金同 周刚 邱玉超[3] 刘四兵 李堃宇 和源[3] 陈浩如 WEN Huaguo;LIANG Jintong;ZHOU Gang;QIU Yuchao;LIU Sibing;LI Kunyu;HE Yuan;CHEN Haoru(Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu 610059,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu 610059,China;Research Institute of Exploration and Development,PetroChina Southwest Oil and Gas Field Company,Chengdu 610041,China;College of Energy Resources,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]成都理工大学沉积地质研究院,成都610059 [2]油气藏地质及开发工程国家重点实验室,成都610059 [3]中国石油西南油气田分公司勘探开发研究院,成都610041 [4]成都理工大学能源学院,成都610059

出　　处：《岩性油气藏》2022年第2期1-16,F0003,共17页Lithologic Reservoirs

基　　金：四川省青年科技创新研究项目“天然气成藏物质基础”(编号:22CXTD0064)资助。

摘　　要：综合利用钻井、测井、露头剖面、岩心和地震等资料,对四川盆地及周缘地区寒武系洗象池组层序岩相古地理开展综合研究。研究结果表明:①研究区洗象池组主要为碳酸盐岩台地沉积环境,自西向东依次发育混积潮坪、局限台地、开阔台地、台地边缘、斜坡—盆地相沉积。应用层序地层学方法可将洗象池组自下而上划分为5个三级层序(SQ1—SQ5)。②局限台地相是四川盆地主要发育的沉积相类型,并可细分为台坪、台内滩、半局限瀉湖3个沉积亚相;台内滩亚相早期呈点状分布,后期随着滩体规模增大,表现为连片分布的特征。③洗象池组发育台内滩颗粒白云岩和台内晶粒白云岩储集体,整体物性呈“低—特低孔渗”的特征;优质储层发育同时受滩相沉积、溶蚀改造和裂缝作用的控制。洗象池组储层虽然单层厚度普遍较薄,但垂向累计厚度可达5~40 m;储层平面展布连续性较差,集中分布在蜀南、川东和川东北部地区。④四川盆地洗象池组发育5个天然气有利勘探区,分别位于川中古隆起、威远古隆起、川东—川东南地区以及川东北地区,勘探面积超过2×10^(4) km^(2),为四川盆地潜在的后备勘探领域。Drilling logs,outcrop profiles,cores and seismic data were used to study the sequence-based lithofacies palaeogeography of Cambrian Xixiangchi Formation in Sichuan Basin and its periphery.The results show that:(1)Xixiangchi Formation was dominated by carbonate platform facies,in which mixed tidal flat,restricted platform,open platform,platform margin,and slope-basin units were developed from west to east.By applying the principles and methods of sequence stratigraphy,the Xixiangchi Formation was divided into five third-order sequences(SQ1-SQ5)from bottom to top.(2)The restricted platform was the dominant sedimentary facies type in Xixiangchi Formation,which can be subdivided into three sedimentary subfacies,namely platform,intra-platform shoal,and semi-restricted lagoon.The intra-platform shoals were distributed in points in the early stage,and later as the shoals increased in size,they were of continuous distribution.(3)There are two kinds of reservoirs of granular dolomite and crystal dolomite in Xixiangchi Formation,and the overall physical properties are characterized by low to extra-low porosity and permeability.The development of high-quality reservoirs was controlled by shoal facies deposition,dissolution reformation and fracturing action.The reservoir thickness is generally thin,but the vertical cumulative thickness mainly ranges from 5 to 40 m.The horizontal distribution of reservoirs is of poor continuity,and is concentrated in southern,eastern and northeastern Sichuan Basin.(4)There are five favorable exploration targets developed in Xixiangchi Formation in Sichuan Basin,which are located in the central Sichuan paleo-uplift,Weiyuan paleo-uplift,eastern to southeast Sichuan and northeastern Sichuan.The available exploration area exceeds 20000 km^(2),which serves as a potential reserve exploration area in Sichuan Basin.

关 键 词：局限台地 台内滩 层序地层 岩相古地理 天然气勘探 洗象池组 寒武系 四川盆地 

分 类 号：TE122[石油与天然气工程—油气勘探] P618.13[天文地球—矿床学]