四川盆地高陡构造区凉高山组页岩油气地质特征  

Geological characteristics of shale oil and gas of Lianggaoshan Formation in high-steep structural zone, Sichuan Basin

作　　者：李楠 洪海涛 李国辉 周红飞 贾敏 康家豪 Li Nan;Hong Haitao;Li Guohui;Zhou Hongfei;Jia Min;Kang Jiahao(Exploration and Development Research Institute,PetroChina Southwest Oil&Gasfield Company,Chengdu,Sich­uan 610041,China;School of Geoscience and Technology,Southwest Petroleum University,Chengdu 610051)

机构地区：[1]中国石油西南油气田公司勘探开发研究院,四川省成都市610041 [2]西南石油大学地球科学与技术学院

出　　处：《天然气勘探与开发》2022年第4期86-95,共10页Natural Gas Exploration and Development

摘　　要：四川盆地下侏罗统凉高山组为三角洲—湖泊沉积,盆地东部地区为沉积次中心。由于盆地东部地区高陡构造发育,过去浅层勘探一直未受重视,研究较少。本次研究通过野外露头、岩心,薄片、扫描电镜、X衍射、氮气吸附等方法,对侏罗系凉高山组岩石学特征、有机地球化学特征、储层特征、含油气性、保存条件等要素进行分析,指出川东高陡构造区凉高山组湖相页岩油气具有较大的勘探潜力。结果表明:(1)凉高山组页岩厚度大,平均为34 m,以Ⅱ型干酪根类型为主,少量Ⅲ型,有机碳(TOC)平均含量1.4%,Ro值1.0%~1.4%,平均孔隙度3.49%,具备良好的页岩油气地质条件。(2)凉高山组为粉砂岩、细砂岩与富有机质泥页岩的混合沉积,发育砂岩及页岩两种储层,储层品质优,烃储搭配良好,利于页岩油气富集。(3)川东地区凉高山组页岩脆性矿物平均含量61.3%,水平应力差较小,向斜区地层压力系数大于1.0,有利于页岩储层改造和油气富集。(4)距离断裂带5 km以外,埋深1 000 m以深的地区保存条件好,勘探潜力大,确定开江、涪陵及忠县地区为勘探有利区。The Lower Jurassic Lianggaoshan Formation in Sichuan Basin is a deltaic-lacustrine deposit, with the sub-center of deposition in eastern basin. The research on shallow exploration was not valued in the past due to the high-steep structures developed in the eastern basin. In this study, the Jurassic Lianggaoshan Formation was analyzed in terms of petrological and organic geochemical characteristics, reservoir properties, hydrocarbon-bearing potential, and preservation conditions by using the methods of field outcrops,cores, thin sections, scanning electron microscopy, X-ray diffraction, and nitrogen adsorption, indicating a great exploration potential of shale oil and gas in this high-steep structural zone. Results show that the shale in Lianggaoshan Formation is 34 m thick on average,dominated by Type II kerogen with minor Type III, with an average TOC of 1.4%, Ro of 1.0%–1.4%, and average porosity of 3.49%,showing good geological conditions. The Lianggaoshan Formation is the mixed deposits of siltstone, fine sandstone and organic-rich shale, with two types of high-quality reservoirs(sandstone and shale) developed. The source-reservoir assemblage is favorable for hydrocarbon enrichment. The shale exhibits an average content of brittle minerals of 61.3%, small horizontal stress difference, and formation pressure in the syncline area greater than 1.0, which are conducive to reservoir stimulation and hydrocarbon accumulation. The areas, 5 km away from the fault zone and deeper than 1 000 m of burial depth, have good preservation conditions and great exploration potential. Favorable exploration zones such as Kaijiang, Fuling and Zhongxian were identified.

关 键 词：四川盆地 高陡构造区 早侏罗世 凉高山组 湖相页岩 地质特征 保存条件 勘探潜力 

分 类 号：P618.13[天文地球—矿床学]