北部湾盆地涠西南凹陷东南斜坡原油成因类型及成藏特征

凹陷油气勘探具有重要指导意义。
关键词：碳同位素；生物标志化合物；油源对比；成藏特征；涠西南凹陷；北部湾盆地
中图分类号：TE122.1
文献标志码：A
Genesis types and accumulation characteristics of crude oil in southeast slope of Weixinan Depression，Beibuwan Basin
岩的上组合和流二段底部油页岩-流三段上部泥岩的下组合。③应用生物标志物和同位素组成等参数
进行油源精细对比可以得出，第 Ⅰ 类原油来源于上组合，第 Ⅱ 类原油来源于下组合。烃源岩岩相控制
了不同类型原油的分布，东南斜坡的流二段、流三段、角尾组、下洋组及基底风化壳均是寻找第 Ⅱ 类原
油的有利区，东南斜坡流一段岩性圈闭是寻找第 Ⅰ 类原油的有利区。该研究成果对北部湾盆地涠西南
展了原油生物标志物分析和同位素等地球化学分析。结果表明：①涠西南凹陷东南斜坡原油可 划分为
2 类，Ⅰ类为具有较低的 4-甲基甾烷丰度和较轻的碳同位素特征的原油，主要分布在流一段；Ⅱ类原油
具有较高的 4-甲基甾烷丰度和较重的碳同位素特征，主要见于流二段、流三段和涠洲组。②东南斜坡
钻遇流沙港组烃源岩，地球化学特征揭示其存在上、下 2 个供烃组合，即包括流一段泥岩-流二段中部泥
Basin. Lithologic Reservoirs，2020，32（1）：11-18.
北部湾盆地涠西南凹陷东南斜坡原油成因类型 及成藏特征
金秋月
（中海石油（中国）有限公司湛江分公司，广东 湛江 524057）
摘要：北部湾盆地涠西南凹陷东南斜坡是重要的油气聚集区。为研究其原油成因类型及成藏特征，开
第 32 卷 第 1 期 2020 年 2 月
岩性油气藏 LITHOLOGIC RESERVOIRS
Vol. 32 No. 1 Feb. 2020
文章编号：1673-8926（2020）01-0011-08
DOI：10.12108/yxyqc.20200102
引用：金秋月 . 北部湾盆地涠西南凹陷东南斜坡原油成因类型及成藏特征 . 岩性油气藏，2020，32（1）：11-18. Cite：JIN Q Y. Genesis types and accumulation characteristics of crude oil in southeast slope of Weixinan Depression，Beibuwan
JIN Qiuyue
（Zhanjiang Branch of CNOOC Limited，Zhanjiang 524057，Guangdong，China）
Abstract：The southeast slope in Weixinan Depression of Beibuwan Basin is an important hydrocarbon accumu‐ lation area. In order to study the genesis types and accumulation characteristics of its crude oil，the biomarkers and isotopic geochemical characteristics of the crude oil in the southeast slope were analyzed. The results show that：（1）The crude oil in the southeast slope can be divided into two types. The first type of crude oil has low 4methyl sterane abundance and low carbon isotope，and mainly distributed in the first member of Liushagang For‐ mation，while the second type of crude oil has high 4-methyl sterane abundance and higher carbon isotope，and mainly distributed in the second and third member of Liushagang Formation and Weizhou Formation.（2）Hydro‐
区。Email：jinqiuyue2007@。12岩性油气藏来自第 32 卷 第 1 期
carbon source rocks in the southeast slope can be divided into two hydrocarbon combination through geochemistry characteristics in combination with sedimentary environment. The upper hydrocarbon combination mainly in‐ cludes the mudstone of the first member of Liushagang Formation and the middle mudstone of the second mem‐ ber of Liushagang Formation，while the lower hydrocarbon combination mainly includes the bottom oil shale of the second member of Liushagang Formation and the upper mudstone of the third member of Liushagang Forma‐ tion.（3）Through analyzing the biomarkers and isotopic characteristics of oil and source rocks，it is concluded that the first type of crude oil is from the upper hydrocarbon combination，and the second type of crude oil is from the lower hydrocarbon combination. The petrofacies of source rocks controlled the distribution of different types of crude oil. The second and third member of Liushagang Formation，Jiaowei Formation，Xiayang Forma‐ tion and basement weathering crust in the southeast slope are all favorable areas for searching for the second type of crude oil，while lithologic traps in the first member of Liushagang Formation are favorable areas for searching for the first type of crude oil. Key words：carbon isotope；biomarkers；oil source correlation；accumulation characteristics；Weixinan Depression；Beibuwan Basin
收稿日期：2019-07-08；修回日期：2019-07-25；网络首发日期：2019-08-09 基金项目：国家科技重大专项“南海西部凹陷比较性研究与有利勘探方向预测”（编号：2016ZX05024002-009）和“南海西部海域低渗油藏
勘探开发关键技术”（编号：2016ZX05024-006）联合资助 作者简介：金秋月（1988—），男，硕士，工程师，主要从事石油地质、油气成藏综合研究工作。地址：（524057）广东省湛江市坡头区南油一