四川盆地及其周缘海相页岩有机质炭化区分布规律与主控因素浅析  

Analysis on carbonization distribution and main controlling factors of organic matter in marine shale in Sichuan Basin and its periphery

作　　者：王玉满[1] 魏国齐[1] 沈均均[2] 邱振[1] 李新景[1] 张琴[1] 张磊夫 王灿辉 刘雯 WANG Yuman;WEI Guoqi;SHEN Junjun;QIU Zhen;LI Xinjing;ZHANG Qin;ZHANG Leifu;WANG Canhui;LIU Wen(PetroChina Research Institute of Petroleum Exploration and Development,Beijing 100083,China;Yangtze University,Wuhan 430100,China)

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]长江大学,湖北武汉430100

出　　处：《天然气地球科学》2022年第6期843-859,共17页Natural Gas Geoscience

基　　金：中国石油科技项目“海相页岩气勘探开发技术研究”(编号:2021DJ1904);中国石油勘探与生产分公司海相页岩气选区课题(编号:kt2018-01-06)联合资助。

摘　　要：高过成熟海相页岩有机质炭化点(区)的分布规律和主控因素是页岩气勘探面临的重要课题。围绕四川盆地及其周缘下寒武统和下志留统页岩分布区,以重点炭化区精细解剖为基础,开展了2套页岩有机质炭化区精细预测和热成熟度区域编图,探索海相页岩有机质炭化区分布规律和主控因素。研究认为:(1)在下志留统页岩分布区,存在川东—鄂西、鄂西北部、川南西部和仁怀—渝西南4个有机质炭化区,面积近40000 km^(2),其中川南西部炭化区主体位于峨眉玄武岩分布区。(2)在下寒武统页岩分布区,有机质炭化区面积占比超过80%,非炭化区仅分布于威远—资阳、磨溪—高石梯、长阳和瓮安—镇远等4个区块,面积约为62600 km^(2)。(3)峨眉火成岩省为晚二叠世的极热事件,使得川南西部下志留统和下寒武统页岩热成熟度RO值分别增加0.2%~0.4%和0.2%~1.0%。马边—峨边位于峨眉玄武岩厚度高值区,也是下寒武统和下志留统页岩有机质炭化程度最严重区域。(4)下寒武统和下志留统页岩有机质炭化的主控因素既有相似之处,也存在一定差异。前者主控因素为长期的深埋背景,晚二叠世的极热事件仅使局部地区炭化程度更趋严重。后者主控因素相对复杂,在仁怀—渝西南、川东—鄂西、鄂西北3个地区受深埋背景控制,在川南西部则受深埋背景和晚二叠世的高地温作用双重控制。The distribution and main controlling factors of organic matter carbonization points(zones)of overmature marine shale are important issues for shale gas exploration.This paper focuses on the Lower Cambrian and Lower Silurian shale in the Sichuan Basin and its periphery.Based on the detailed anatomy of key carbonization areas,predictions of shale organic matter carbonization areas and regional mapping of thermal maturity are carried out to explore and reveal the distribution and main controlling factors of the carbonization zones of organic matter in the two sets of shales.Four preliminary conclusions were obtained:(1)In the Lower Silurian shale distribution area,there are four organic matter carbonization zones,namely,eastern Sichuan-western Hubei,northwestern Hubei,southern Sichuan and Renhuai-southwestern Chongqing,covering an area of nearly 40000 km^(2),of which the main part of the western carbonization zone in southern Sichuan is located in the Emei basalt distribution area.(2)In the Lower Cambrian shale distribution area,the organic carbonization area accounts for more than 80%.The non-carbonization area is only distributed in Weiyuan-Ziyang,Moxi-Gaoshiti,Changyang and Weng’an-Zhenyuan with an area of about 62600 km^(2).(3)The Emei igneous rock event was an extreme heat event in the Late Permian,which increased the thermal maturity ROvalue of the Lower Silurian and Lower Cambrian shale in the western part of southern Sichuan by 0.2%-0.4% and 0.2%-1.0%,respectively.MabianEbian is located in the high-value area of the Emei basalt thickness,and is also the area with the highest degree of carbonization of organic matter in the Lower Cambrian and Lower Silurian shale.(4)The main controlling factors of organic matter carbonization of the Lower Cambrian and Lower Silurian shale have similarities and differences.The main controlling factor of the former is the long-term deep burial background,and the extremely thermal event in the Late Permian only made the degree of carbonization in some areas more serious.The l

关 键 词：四川盆地 下寒武统 下志留统 热成熟度 有机质炭化 低电阻率响应 峨眉火成岩省 

分 类 号：TE122.1[石油与天然气工程—油气勘探]