下扬子地区海陆过渡相页岩气成藏条件与主控因素:以萍乐坳陷二叠系乐平组为例  

Accumulation Conditions and Main Factors of Marine-Continental Transitional Shale Gas in the Lower Yangtze Area of China:A Case of Permian Leping Formation in the Pingle Depression

作　　者：吴小力[1] 李荣西[1] 李尚儒 何攀 邓金辉 乔博 王建广 韦景林 井阳 Wu Xiaoli;Li Rongxi;Li Shangru;He Pan;Deng Jinhui;Qiao Bo;Wang Jianguang;Wei Jinglin;Jing Yang(School of Earth Science and Resource, Chang＇an University, Xiran 710054, China;Shale Gas Investigation and Development Research Institute of Jiangxi, Nanchang 330002, China;Exploration and Development Research Institute, Huabei Oil{ield Company, CNPC, Renqiu Hebei 062552, China;Changqing Division, PetroChina Logging Co. Ltd., PetroChina, Xi＇an 710299, China)

机构地区：[1]长安大学地球科学与资源学院,西安710054 [2]江西省页岩气调查开发研究院,南昌330002 [3]中国石油华北油田分公司勘探开发研究院,河北任丘062552 [4]中国石油测井有限公司长庆事业部,西安710299

出　　处：《地质科技情报》2018年第1期160-168,共9页Geological Science and Technology Information

基　　金：国家自然科学基金项目(41173055);中央高校基本科研业务费专项资金项目(310827172101)

摘　　要：萍乐坳陷二叠系乐平组是典型的下扬子地区海陆过渡相泥页岩的发育层系。通过野外地质调查、样品采集和分析测试等对萍乐坳陷二叠系乐平组泥页岩的发育特征、有机地球化学特征、储层特征和含气性等页岩气成藏地质条件进行了分析。结果表明:萍乐坳陷二叠系乐平组页岩单层厚度小、累积厚度大,横向、纵向连续性差;有机质丰度较高,w(TOC)以1.0%~2.5%为主,有机质类型以Ⅲ型和Ⅱ2型为主,有机质成熟度Ro分布在0.6%~4.5%之间,以高成熟-过成熟为主。页岩矿物组成中黏土矿物较为富集,储层孔隙类型主要为微孔隙和微裂缝,储层物性较差;总含气量和最大吸附气含量都较小。在页岩气成藏地质条件研究的基础上,结合区域沉积-构造背景的分析表明,页岩气成藏控制因素为:沉积环境、构造运动和保存条件。综合分析表明萍乐坳陷二叠系乐平组页岩气成藏条件一般,但在有机质丰度高、物性较好、埋藏适中的构造稳定地区仍然有较好的页岩气资源前景。Permian Leping Formation in the Pingle Depression is typical marine-continental transitional shale in the Lower Yangtze area of China.Based on the field geological investigation,sample collection and laboratory analysis,this paper discusses the shale gas accumulation conditions of Permian Leping Formation in the depression such as distribution characteristics,geochemical characteristics,reservoir characteristics and gas content.The results show that Permian Leping Formation shales are horizontally and vertically changeable and have relatively small monolayer thickness and big overall thickness.The total organic carbon content of the shale is high and distributed mainly1.0%-2.5%.The organic matter types are mainly typeⅢandⅡ2.The thermal evolution degree of the shale is mainly in high mature and post mature phases with Roin the range of 0.6%-4.5%.Clay content in the shale reservoir is high,and reservoir pore types are mainly micro pores and micro cracks with relatively poor reservoir properties.Both the gas content and the Langmuir gas volume are relatively small.Combining the study of shale gas accumulation conditions and the regional sedimentary-tectonic background,this paper suggests that sedimentary environments,tectonic movement and gas preservation conditions are the main control factors of the shale gas accumulation.The comprehensive analysis shows that accumulation conditions of Permian Leping Formation shale gas are not good enough,but the prospect of the shale gas resources is still good in the areas with high organic material content,relatively good reservoir properties,moderate burial depth and stable tectonic setting.

关 键 词：页岩气 海陆过渡相 下扬子地区 萍乐坳陷 二叠系 成藏条件 

分 类 号：P618.13[天文地球—矿床学]