川中地区茅口组碳酸盐岩层序地层及沉积相特征  

Sequence stratigraphy and sedimentary facies characteristics of the Maokou Formation carbonate rocks in central Sichuan Basin

作　　者：匡明志 张小兵[1,2] 袁海锋[1,2] 陈聪 张玺华[3] 彭瀚霖 徐婷 肖钦仁[1,2] 李天军 山述娇 KUANG Mingzhi;ZHANG Xiaobing;YUAN Haifeng;CHEN Cong;ZHANG Xihua;PENG Hanlin;XU Ting;XIAO Qinren;LI Tianjun;SHAN Shujiao(College of Energy,Chengdu University of Technology,Chengdu 610059,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China;Research Institute of Exploration and Development,PetroChina Southwest Oil&Gas Field Company,Chengdu 610041,China)

机构地区：[1]成都理工大学能源学院,四川成都610059 [2]成都理工大学油气藏地质及开发工程全国重点实验室,四川成都610059 [3]中国石油西南油气田分公司勘探开发研究院,四川成都610041

出　　处：《古地理学报》2024年第5期1201-1220,共20页Journal of Palaeogeography：Chinese Edition

基　　金：国家自然科学基金面上项目(编号:41872130);四川省自然科学基金青年基金项目(编号:2023NSFSC0759)共同资助.

摘　　要：四川盆地二叠系茅口组碳酸盐岩是油气勘探的重要层位,川中八角场—磨溪—龙女寺地区茅二段目前已获得勘探突破,但因其层序地层结构尚不明确,制约了茅口组沉积演化研究与储集层预测。本研究基于川中广安华蓥山二崖剖面茅口组高精度岩相特征,综合实际钻井资料,开展茅口组沉积相和层序地层格架分析,并解释层序格架对储集层发育特征和分布规律的控制作用。研究结果表明:(1)川中地区茅口组碳酸盐岩可分为8类岩石微相,在茅口组沉积中晚期,构造作用驱动茅口组由缓坡沉积体系向“台地—台内海槽”沉积体系转换。(2)栖霞组上部层序界面SB1和茅二下亚段上部层序界面SB2均为Ⅱ型岩相转换界面,茅二上亚段顶界面SB3为Ⅰ型淹没不整合界面,茅三段顶界面SB4为Ⅰ型剥蚀不整合面。(3)二崖剖面茅口组可划分为3个三级层序、5个四级层序:茅一段构成三级层序SQ1的海侵体系域;茅二下亚段中—下部对应三级层序SQ1的高位体系域,而上部发育三级层序SQ2陆架边缘体系域;茅二上亚段和茅三段分别对应三级层序SQ2和SQ3。(4)磨溪—龙女寺地区茅二下亚段云化储集层分布在三级层序SQ1高位体系域和三级层序SQ2陆架边缘体系域,分别以准同生晚期和准同生早期云化作用为主,受控于Ⅱ型层序界面SB2;广安—八角场地区茅二上亚段台缘滩相白云岩储集层分布在三级层序SQ2高位体系域并且受控于Ⅰ型层序界面SB3,经历了准同生早期基质云化—准同生晚期颗粒溶蚀—埋藏期云化作用阶段。该研究为四川盆地茅口组白云岩储集层分布规律的预测和成因研究提供了层序和沉积约束,对茅口组的油气勘探具有一定的参考意义。The carbonate rocks of the Permian Maokou Formation in the Sichuan Basin are crucial for oil and gas exploration.Significant breakthroughs have been achieved in the exploration of the Maokou Formation in the Bajiaochang-Moxi-Longnüsi area of central Sichuan Basin.However,the unclear stratigraphic structure impedes the study of sedimentary evolution and reservoir prediction of the Maokou Formation.This research is based on high-precision lithofacies characteristics of the Maokou Formation at the Er’ya section in the Huaying Mountain of Guang’an in central Sichuan Basin.It integrates actual drilling data to analyze the sedimentary facies and sequence stratigraphic framework of the Maokou Formation,explaining the influence of the sequence framework on the development characteristics and distribution patterns of the reservoirs.The research findings indicate that:(1)The carbonate rocks of the Maokou Formation in the central Sichuan Basin can be divided into eight lithofacies.During the late stage of deposition of the Maokou Formation,tectonic activity facilitated the transition from a gentle slope sedimentary system to a“platform-platform interior sea trough”sedimentary system.(2)The upper sequence interface SB1 of the Qixia Formation and the upper sequence interface SB2 of the lower submember of Member 2 of the Maokou Formation are both classified as type II lithofacies transition interfaces.The top interface SB3 of the upper submember of Member 2 of the Maokou Formation is identified as a type I drowning unconformity interface,while the top interface SB4 of Member 3 of the Maokou Formation is classified as a type I erosion unconformity interface.(3)The Maokou Formation in the Er’ya section can be divided into three third-order sequences and five fourth-order sequences.Member 1 of the Maokou Formation constitutes the transgressive system tract of third-order sequence SQ1.The middle to lower parts of the lower submember of Member 2 correspond to the high-position system tract of third-order sequence SQ1,whi

关 键 词：碳酸盐岩 微相分析 层序划分 储集层分布 中二叠统 四川盆地 

分 类 号：P539.2[天文地球—古生物学与地层学]