四川盆地西北部中二叠统茅口组岩相古地理、古岩溶地貌恢复及其油气地质意义  

Reconstruction and petroleum geological significance of lithofacies paleogeography and paleokarst geomorphology of the Middle Permian Maokou Formation in northwestern Sichuan Basin,SW China

作　　者：钟原 杨跃明[3] 文龙 罗冰 肖笛 李明隆 陈聪 赵立可 芦飞凡 谭秀成 ZHONG Yuan;YANG Yueming;WEN Long;LUO Bing;XIAO Di;LI Minglong;CHEN Cong;ZHAO Like;LU Feifan;TAN Xiucheng(Research Institute of Exploration and Development,PetroChina Southwest Oil and Gas Field Company,Chengdu 610041,China;Division of Key Laboratory of Carbonate Reservoirs,CNPC,Southwest Petroleum University,Chengdu 610500,China;PetroChina Southwest Oil and Gas Field Company,Chengdu 610051,China;School of Earth Sciences and Engineering,Nanjing University,Nanjing 210023,China)

机构地区：[1]中国石油西南油气田公司勘探开发研究院,成都610041 [2]中国石油天然气集团有限公司碳酸盐岩储层重点实验室西南石油大学研究分室,成都610500 [3]中国石油西南油气田公司,成都610051 [4]南京大学地球科学与工程学院,南京210023

出　　处：《石油勘探与开发》2021年第1期81-93,共13页Petroleum Exploration and Development

基　　金：国家自然科学基金项目(41802147);中国博士后科学基金资助项目(2019M651785);中国石油-西南石油大学创新联合体科技合作项目(2020CX010000)。

摘　　要：基于野外剖面、地震、测井及钻井等资料分析,结合大地构造背景,对四川盆地西北部(简称川西北)地区中二叠统茅口组岩相古地理及古岩溶地貌特征进行恢复并探讨其油气地质意义。研究表明,川西北地区茅口组可进一步划分为LSC1、LSC2、LSC3共3个长期旋回,分别对应茅一段、茅二段、茅三段。受上扬子地块北缘勉略古洋盆扩张所形成的伸展构造及地幔柱隆升产生的基底断裂控制,在北西西及北东方向产生构造分异,沉积基底自北向南呈幕式沉降,导致茅一段—茅三段沉积体系由碳酸盐台地逐渐演变为台地-斜坡-广海陆棚共存的特征。根据残余厚度恢复出岩溶高地、岩溶斜坡、岩溶洼地等古岩溶地貌单元,岩溶地貌单元是在沉积地貌基础上继承性发展形成的。沉积相及古岩溶地貌对于油气储集具有重要意义,高能滩与溶丘组合、台缘斜坡与岩溶斜坡组合是川西北地区茅口组最优质的储集区带组合类型,将优质储集相带叠合古岩溶地貌,对这两类储集区带平面展布特征进行预测。研究结果将为四川盆地中二叠统茅口组勘探部署提供新的思路与借鉴。Based on analysis of outcrop,drilling,logging and seismic data,and geotectonic background,the lithofacies paleogeography and paleokarst geomorphology of the Middle Permian Maokou Formation in the northwestern Sichuan Basin were reconstructed,and the petroleum geological significance of the lithofacies paleogeography and paleokarst geomorphology were discussed.The Maokou Formation is divided into 3 long-term cycles,namely LSC1,LSC2 and LSC3,which correspond to the Member 1,Member 2 and Member 3 of the Maokou Formation,respectively.Controlled by the extensional structure caused by opening of the Mianlue Ocean in the north margin of the upper Yangtze blocks and basement faults produced by mantle plume uplifting,the area had tectonic differentiation in NWW and NE,and sedimentary basement took on episodic settlement from north to south,as a result,the sedimentary systems of Member 1 to Member 3 gradually evolved from carbonate platform to platform-slope-continental shelf.According to the residual thickness,paleokarst geomorphologic units such as karst highland,karst slope and karst depression at different stages were reconstructed.The karst geomorphological units were developed successively on the basis of sedimentary geomorphology.Sedimentary facies and paleokarst geomorphology are of great significance for oil and gas accumulation.The Maokou Formation in northwestern Sichuan has two kinds of most favorable reservoir zone combinations:high energy grain shoal and karst monadnock,platform margin slope and karst slope.Based on this understanding,the planar distribution of the two kinds of reservoir zones were predicted by overlapping the favorable reservoir facies belt with paleokarst geomorphology.The study results provide a new idea and reference for the exploration deployment of the Middle Permian Maokou Formation in the Sichuan Basin.

关 键 词：中二叠统 茅口组 层序地层 岩相古地理 古岩溶地貌 沉积相 四川盆地西北部 

分 类 号：TE121.1[石油与天然气工程—油气勘探]