蓬莱19-3/25-6油田未熟—低熟油特征与成因  

Characteristics and genesis of immature and low-matire oils in Penglai 19-3 and 25-6 oilfields

作　　者：王广源 周心怀 王昕 王应斌 郭永华 刘廷海 

机构地区：[1]中国海洋石油(中国)有限公司天津分公司渤海油田勘探开发研究院,天津300452

出　　处：《石油实验地质》2014年第2期230-237,共8页Petroleum Geology & Experiment

基　　金：国家科技重大专项(2011ZX05023-006-002)资助

摘　　要：利用大量最新的原油和烃源岩等实验资料,系统分析了蓬莱19-3/25-6油田未熟—低熟油的特征、来源及其形成条件,并探讨了未熟—低熟油的主要成因机理。研究结果表明,蓬莱19-3/25-6油田未熟—低熟油埋藏较浅,具有密度高、黏度高、饱和烃含量低、饱/芳比低、非烃含量高、非沥比高、Pr/Ph低、重排甾烷丰度低和Ts<Tm等特征。油源对比结果表明,这些未熟—低熟油来自本井区及邻近沙一、二段和沙三段未熟—低熟烃源岩,强还原的半咸水—咸水沉积环境、烃源岩有机质丰度高且类型好、主要生烃母质为藻类和有机质中的各种细菌是这2套烃源岩形成未熟—低熟油的有利地质条件,藻类有机质早期生烃、细菌改造有机质早期生烃和碳酸盐岩低温热催化早期生烃是主要成因机理,这些成因机理共同作用生成了大量的未熟—低熟油资源,对蓬莱19-3/25-6大型油田的形成具有不可忽视的贡献。Based on the experimental data of crude oils and source rocks, the characteristics, sources and generation conditions of immature and low-mature oils from the Penglai 19-3/25-6 oilfields were analyzed systematically, and the main generation mechanisms were also discussed. The immature and low-mature oils from the Penglai 19-3/25-6 oil-fields were buried in shallow formations, and were featured by high density, high viscosity, low content of saturated hydrocarbon, low saturated/aromatic ratio, high content of non-hydrocarbon, high non-hydrocarbon/asphalt ratio, low Pr/Ph ratio, low abundance of rearranged sterane and Ts＆lt;Tm. The correlations of oils and sources showed that these immature and low-mature oils came from the immature and low-mature source rocks in the first-second and third members of the Shahejie Formation in the Penglai 19-3/25-6 oilfields and their neighboring areas. Strong anoxic semi-saline/saline environments, high organic matter abundance and oil-prone type kerogen, alga as main hydrocarbon-generating material, and bacterium in organic matter were the favorable geologic conditions for the generation of immature and low-mature oils from the above-mentioned 2 sets of source rocks. The main generation mechanism included the early-stage hydrocarbon generations of organic matter in algae, organic matter reformed by bacterium, and carbonate catalysis at low temperature. A large amount of immature and low-mature oils which generated under the joint action of the mechanisms was contributive for the formation of the Penglai 19-3/25-6 oilfields.

关 键 词：未熟-低熟油 生标化合物 成因机理 蓬莱19-3油田 蓬莱25-6油田 

分 类 号：TE122.1[石油与天然气工程—油气勘探]