下扬子地区上二叠统页岩气成藏条件分析  

Analysis of shale gas accumulation conditions of the Upper Permian in the Lower Yangtze Region

作　　者：李琪琪 徐尚 陈科 宋腾 孟凡洋 何生[1] 陆永潮[1] 石万忠[1] 苟启洋 王雨轩 LI Qiqi;XU Shang;CHEN Ke;SONG Teng;MENG Fanyang;HE Sheng;LU Yongchao;SHI Wanzhong;GOU Qiyang;WANG Yuxuan(Key Laboratory of Tectonics and Petroleum Resources,Ministry of Education,China University of Geosciences,Wuhan 430074,Hubei,China;Shandong Provincial Key Laboratory of Deep Oil&gas,China University of Petroleum(East China),Qingdao 266580,Shandong,China;Center of Oil&Gas Survey,China Geological Survey,Beijing 100083,China)

机构地区：[1]中国地质大学(武汉)构造与油气资源教育部重点实验室,湖北武汉430074 [2]山东省深层油气重点实验室,中国石油大学(华东),山东青岛266580 [3]中国地质调查局油气资源调查中心,北京100083

出　　处：《中国地质》2022年第2期383-397,共15页Geology in China

基　　金：国家自然科学基金优秀青年科学基金(42122017);国家自然科学基金创新群体(41821002);山东省重点研发计划(2020ZLYS08);中国地质调查局项目(DD20190561);中国石油大学(华东)自主创新研究计划(21CX06001A)联合资助。

摘　　要：【研究目的】下扬子地区上二叠统广泛发育龙潭组-大隆组暗色页岩,是中国页岩气调查的重点层位。目前该区勘探程度低,导致对该区页岩气成藏条件认识不清。【研究方法】通过龙潭组和大隆组页岩地球化学特征、储集性能,以及保存条件等方面的研究,对该区页岩气资源潜力进行了评价,对有利区进行了优选。【研究结果】龙潭组和大隆组有机质丰度高,TOC含量普遍大于2.0%,热演化程度适中(介于1.3%~2.5%),储集空间以墨水瓶和狭缝状中孔为主,脆性矿物含量普遍高于50%,具有较好的生烃物质基础和可压裂性。龙潭组页岩累计厚度较大,具有良好的自封闭能力,保存条件总体优于大隆组。二者均发育多种类型的裂缝,是页岩气逸散的主要通道,此外,后期岩浆活动较为频繁,对于页岩气有很强的破坏作用,保存条件是页岩气富集的关键。【结论】下扬子地区上二叠统页岩气选区评价应以沉积环境、生烃能力、储集性能等为基础,以页岩气保存条件为关键,采取“强中找弱”的原则进行,最终在下扬子地区大隆组和龙潭组分别划分了5个有利区。This paper is the result of oil and gas exploration engineering.[Objective]The dark shale of the Longtan-Dalong Formation is widely developed in the Upper Permian of the Lower Yangtze region, which is the key formation for shale gas exploration in China. At present, the degree of exploration in this area is low,resulting in unclear understanding of shale gas accumulation conditions. [Methods]The geochemical characteristics, reservoir properties, and preservation conditions of the Longtan Formation and Dalong Formation shales were studied to evaluate shale gas exploration potential and optimize favorable exploration areas. [Results]The organic matter abundance of the Longtan Formation and Dalong Formation is high, TOC content is generally greater than 2.0%, the thermal evolution degree is moderate(between 1.3% and 2.5%), the reservoir space is mainly ink bottle and slit-like mesopores, the brittle mineral content is generally higher than 50%,with good hydrocarbon generation material basis and fracturability. The Longtan Formation shale is thick, with good self-sealing ability, and the preservation conditions are generally better than those of the Dalong Formation. Both of them develop various types of fractures, which are the main channels for shale gas escape. In addition, the late magmatic activity is frequent, which has a strong destructive effect on shale gas, and the preservation conditions are the key to shale gas enrichment. [Conclusions]The evaluation of the Upper Permian shale gas in the Lower Yangtze area should be based on sedimentary environment, hydrocarbon generation capacity, and reservoir conditions, taking the shale gas preservation conditions as the key and adopting the principle of finding weak areas in the context of strong tectonic activity. Finally, five favorable areas were divided in the Dalong Formation and Longtan Formation in the Lower Yangtze area.

关 键 词：页岩气 海陆过渡相 富集条件 上二叠统 下扬子地区 油气勘查工程 

分 类 号：P641[天文地球—地质矿产勘探]