鄂尔多斯盆地中生界延长组陆相页岩油富集特征与资源潜力

Enrichment characteristics and resource potential of continental shale oil in Mesozoic Yanchang Formation, Ordos Basin

付锁堂 姚泾利 李士祥 周新平 李明瑞

FU Suotang YAO Jingli LI Shixiang ZHOU Xinping LI Mingrui

低渗透油气田勘探开发国家工程实验室, 西安 710018 中国石油 长庆油田公司, 西安 710018 中国石油 长庆油田公司 勘探事业部, 西安 710018 中国石油 长庆油田公司 勘探开发研究院, 西安 710018

National Engineering Laboratory of Low Permeability Oil and Gas Field Exploration and Development, Xi'an, Shaanxi 710018, China PetroChina Changqing Oilfield Company, Xi'an, Shaanxi 710018, China Exploration Department of PetroChina Changqing Oilfield Company, Xi'an, Shaanxi 710018, China Research Institute of Exploration and Development, PetroChina Changqing Oilfield Company, Xi'an, Shaanxi 710018, China

鄂尔多斯盆地中生界延长组长7段主要发育半深湖—深湖相泥页岩，是盆地中生界油藏的主力烃源岩层，源内页岩油资源丰富。与北美海相页岩油相比，长7页岩油沉积相变化快、地层连续性差、非均质性强，其富集特征和分布规律更为复杂。基于盆地30余口长7段全取心井开展精细岩心描述和3万余块次实验分析测试，明确了长7烃源岩层系页岩油基本地质特征和富集主控因素，客观评价了页岩油资源潜力，2019年发现了10亿吨级庆城页岩油大油田。长7段泥页岩层系发育源储分异型（Ⅰ类）、源储一体型（Ⅱ类）及纯页岩型（Ⅲ类）三种页岩油类型。高有机质丰度烃源岩是页岩油富集的物质基础，多成因类型砂岩储层发育数量众多的微纳米孔喉单元，是页岩油赋存的主要空间与渗流通道，多类型细粒沉积岩间互分布构成了良好的源储共生配置，高强度生烃和异常高压持续充注形成了源内高含油饱和度页岩油。长7段页岩油发育陇东、陕北两大含油区带，初步落实页岩油储量规模30~50亿吨，2025年有望建成500万吨页岩油生产基地。

The Chang 7 Member of the Mesozoic Yanchang Formation in the Ordos Basin mainly developed as a semi-deep to deep lacustrine mudstone and shale.It is the main oil-rich source bed for the Mesozoic reservoir in the basin. Compared with North American marine shale oil, the Chang 7 shale oil has diverse sedimentary facies, poor stratigraphic continuity and strong reservoir heterogeneity, and its enrichment and distribution characteristics are more complicated. The fine scale core descriptions of the Chang 7 Member from more than 30 wells and the experimental testing and analysis of more than 30 000 samples were carried out. The basic geological characteristics and main factors controlling enrichment of shale oil in the Chang 7 source beds were clarified, and the shale oil resource potential was evaluated. A major breakthrough was made in the Chang 7 Member shale oil exploration, and the Qingcheng Oilfield, a 1 billion ton large shale oil field, was discovered in 2019. There are three types of shale oil in the Chang 7 Member of Yanchang Formation, including the source-reservoir differentiation type (type Ⅰ), the source-reservoir integration type (type Ⅱ) and the pure shale type (type Ⅲ). The hydrocarbon source rocks with high abundance of organic matter provides the material base for the enrichment of shale oil, the sandstone reservoirs have numerous micro pores and nano throats, which are the main spaces and seepage channels for shale oil. The inter-distribution of multiple types of fine-grained sediments constitutes a good source-reservoir configuration, and high-intensity hydrocarbon charging and abnormal high pressure form reservoirs with high saturation in source rocks. The Chang 7 Member developed in the Longdong and northern Shaanxi shale oil-bearing areas, and the shale oil reserves have been initially estimated to be 3 to 5 billion tons, showing great exploration and development potential. By 2025, a production base of 5 million tons is expected.

国家科技重大专项“大型油气田及煤层气开发” 2016ZX05050;国家重点基础研究发展计划（973计划）“淡水湖盆细粒沉积与富有机质页岩形成机理” 2014CB239003

https://doi.org/10.11781/sysydz202005698