川东地区台内洼地二叠系生物礁、滩沉积格局及勘探意义  

Sedimentary pattern and exploration significance of Permian reefs and shoals in intra-platform depressions,eastern Sichuan Basin

作　　者：蒋裕强[1,2] 周亚东 陈智雍 谷一凡[1,2] 付永红 易娟子[3] 张洁伟 蒋增政 Jiang Yu-qiang;Zhou Ya-dong;Chen Zhi-yong;Gu Yi-fan;Fu Yong-hong;Yi Juan-zi;Zhang Jie-wei;Jiang Zeng-zheng(School of Geoscience and Technology y Southwest Petroleum University,Chengdu 610500,China;PetroChina Unconventional Key Laboratory Branch of Southwest Petroleum University,Chengdu 610500,China;Chongqing Gas Field,PetroChina Southwest Oil and Gas Field Company,Chongqing 400021,China;Northeastern Sichuan Oil and Gas District,PetroChina Southwest Oil and Gas Field Company,Dazhou 635000,China;Sichuan Geotech Science and Technology Ltd.,Chengdu 610041,China)

机构地区：[1]西南石油大学地球科学与技术学院,四川成都610500 [2]中国石油非常规重点实验室储层评价实验室,四川成都610500 [3]中国石油西南油气田公司重庆气矿,重庆400021 [4]中国石油西南油气田公司川东北气矿,四川达州635000 [5]四川杰瑞泰克科技有限公司,四川成都610041

出　　处：《天然气地球科学》2019年第11期1539-1550,共12页Natural Gas Geoscience

基　　金：国家科技重大专项“四川盆地大型碳酸盐岩气田开发示范工程”(编号：2016ZX05052);中国石油重大科技攻关项目“四川盆地老区气田稳产保效关键技术研究与应用”(编号：2016E-0607)联合资助

摘　　要：川东地区晚二叠世-早三叠世发育武胜-石柱台内洼地和重庆-綦江台内洼地,明确环台洼边缘分布的生物礁滩沉积格局及演化对四川盆地二叠系-三叠系礁滩气藏勘探的重要指导意义。基于川东地区卷洞、菊花坝、太运和冷水溪剖面长兴组的现场实测和系统取样分析,结合实际钻井资料和前期研究成果,认为长兴组沉积早期,除开江-梁平海槽外,研究区内其余地区均处于缓坡沉积环境,以硅质结核灰岩和泥晶灰岩等较深水沉积为主;而随着长兴组沉积中-晚期海退,开始出现明显的沉积分异现象,由南向北呈"两洼"-"一台"-"一槽"的沉积格局,即重庆-綦江台内洼地亚相及其以北的武胜-石柱台内洼地亚相("两洼")、武胜-石柱台内洼地亚相与开江-梁平海槽之间的台坪亚相("一台")及开江-梁平海槽主体("一槽")。沿武胜-石柱台内洼地南、北两侧台洼边缘带,发育生物礁滩组合,生物礁滩组合在北侧主要发育在长二段-长三段下部,在南侧则发育在长三段上部,具有"北早-南晚"的沉积特征,认为长兴期沉积古地貌上具有"北高-南低"的特点。研究区台内洼地沉积格局及生物礁滩演化规律的明确,为川东地区二叠系长兴组礁滩气藏勘探新领域评价提供了依据。There existed Wusheng-Shizhu and Chongqing-Qijiang intra-platform depressions in eastern Sichuan Basin during the Late Permian to Early Triassic. The clear understanding of sedimentary pattern and evolution of reef-shoal which surrounding the depression-margin has practical significance for guiding the exploration and development of the Permian-Triassic reef and shoal gas reservoirs. Based on measurement,systematic sampling and laboratory analysis of typical outcrops of Changxing Formation such as Juandong section,Juhuaba section,Lengshuixi section and Taiyun section which located in eastern Sichuan Basin,combined with the real drilling data and previous research,it is illustrated that the study area is dominated by ramp sedimentary environment except Kaijiang-Liangping Trough in the early sedimentary period of Changxing Formation. The main deposits are siliceous-nodule limestone and micrite meantime. With the regression in the middle-late sedimentary period of Changxing Formation,distinct sedimentary differentiation began to appear. From south to north in the study area during Changxing period,there is a"Two Depressions"-"One Platform"-"One Trough"sedimentary pattern,i.e. subfacies of Chongqing-Qijiang intra-platform depression and Wusheng-Shizhu intra-platform depression to its north(Two Depressions),platform-terrace subfacies between Wusheng-Shizhu intra-platform depression and Kaijiang-Liangping Trough,and the main body of the Kaijiang-Liangping Trough. In the depression-margin zone on both sides of the intra-platform depression,the reef-shoal assemblage mainly develops in the lower part of Chang2 member-Chang3 member on the north side and in the upper part of Chang3 member on the south side. It has the sedimentary characteristics of"early in north-late in south". It is considered that the sedimentary palaeogeomorphology of Changxing period is characterized by"higher in the north-lower in the south". The clear understanding of sedimentary pattern and evolution law of reef-shoal around Wusheng-Shizhu intra-pla

关 键 词：武胜-石柱 川东地区 礁滩 二叠系 台内洼地 台洼边缘 沉积格局 

分 类 号：TE122.1[石油与天然气工程—油气勘探]