陆相富有机质页岩与泥岩的成藏差异及其在页岩油评价中的意义  

Accumulation contribution differences between lacustrine organic-rich shales and mudstones and their significance in shale oil evaluation

作　　者：赵文智[1] 朱如凯[1] 胡素云[1] 侯连华[1] 吴松涛[1] ZHAO Wenzhi;ZHU Rukai;HU Suyun;HOU Lianhua;WU Songtao(PetroChina Research Institute of Petroleum Exploration&Development,Beijing 100083,China)

机构地区：[1]中国石油勘探开发研究院,北京100083

出　　处：《石油勘探与开发》2020年第6期1079-1089,共11页Petroleum Exploration and Development

基　　金：国家科技重大专项(2016ZX05046、2017ZX05001);中国石油天然气股份有限公司项目(2019E-2601)。

摘　　要：页岩和泥岩的有机质丰度与岩石组构差异较大,决定了二者对常规油气与页岩油气成藏贡献的不同,未来进入源灶区勘探后所倚重的烃源岩评价标准也应有别。页岩沉积于半深湖-深湖环境,沉积速率低并伴有程度不等的化学沉积作用;泥岩多形成于滨-浅湖环境,沉积速率快且多具密度流特征。火山灰沉落与热液注入导致“肥沃效应”、放射性物质促使生物超量超速生长、深水厌氧环境与低沉积速率保护有机物堆积不被稀释等因素促使页岩段有机物富集。页理易剥离成为储集空间,生烃产生的酸性水溶蚀部分颗粒形成增孔效应;泥岩呈块状,黏土矿物含量高,基质孔隙不发育。页岩段总有机碳含量高,页理发育,储集性相对较好,脆性矿物含量相对较高,是页岩油勘探开发最有利的岩相类型。开展页岩与泥岩成藏差异研究,以页岩、泥岩为端元,落实资源分布,确定“甜点”评价参数类型和标准,优选页理发育的“甜点区/段”,使用有效开发技术,对客观评价页岩油资源总量、经济性与规模有效开发都具重要意义。Shales and mudstones differ greatly in organic matter abundance and rock fabric,resulting in their different roles in the formation of conventional and shale oil/gas reservoirs.The evaluation criteria of source rocks are different in the future exploration in self-sourced petroleum systems.Shales are deposited in deep/semi-deep lacustrine at a low deposition rate accompanied with chemical depositions of various degrees,while mudstones are mostly formed in shallow lacustrine/lakeside at a high deposition rate,showing characteristics of density flow.Three factors contribute to the enrichment of organic matter in shales,including the"fertile effect"caused by volcanic ash settling and hydrothermal injection,excessive and over-speed growth of organisms promoted by radioactive materials,and low dilution of organic matter in deep water anaerobic environment where the deposition rate is low.Lamellations in shales tend to be separated to form new storage space,and acid water generated during hydrocarbon generation can dissolve some particles to generate new pores.The massive mudstones with high clay content are of poor matrix porosity.Shales with high total organic carbon,developed laminations,relative good reservoir property,and high brittle mineral content,are the most favorable lithofacies for shale oil exploration and development.It is urgent to carry out investigation on the differences between shale and mudstone accumulation,to identify resources distribution in shale and mudstone formations,determine key parameters and standards for“sweet-spot”evaluation,select“sweet-spot areas/sections”,and adopt effective development technologies.All of these are of great significance for the assessment of shale oil resources and economically and effectively exploitation of shale oil.

关 键 词：页岩 泥岩 总有机碳含量下限 岩石组构 成藏差异 陆相页岩油 甜点选区 

分 类 号：TE122.1[石油与天然气工程—油气勘探]