沾化凹陷渤南洼陷沙河街组原油成因类型及分布特征

Genetic types and distribution characteristics of crude oils from Shahejie Formation in Bonan Subsag, Zhanhua Sag, Jiyang Depression

宋国奇 刘华 蒋有录 谷国翠 刘雅利 卢浩

Song Guoqi Liu Hua Jiang Youlu Gu Guocui Liu Yali Lu Hao

中国石化 胜利油田分公司, 山东 东营 257001 2. 中国石油大学 地球科学与技术学院, 山东 青岛 266580

SINOPEC Shengli Oilfield Company, Dongying, Shandong 257001, China 2. School of Geosciences, China University of Petroleum, Qingdao, Shandong 266580, China

利用饱和烃色谱、色—质谱谱图特征及生物标志化合物指标，在沙河街组不同层系烃源岩地化特征差异性对比的基础上，结合原油地化特征，分析了沾化凹陷渤南洼陷已发现油气的成因类型及其分布规律。分析表明，渤南洼陷发育沙三段和沙四段2套有效烃源岩，其中沙四段烃源岩按照地化特征差异又细分为膏盐间和膏盐下烃源岩，三者在伽马蜡烷含量、姥植比和成熟度指标上存在明显差异。油源对比表明，目前已发现的原油存在5种成因类型，且具有一定的分布规律。沙三Ⅰ型和沙三Ⅱ型原油均来源于沙三段烃源岩，但是在成熟度和分布上明显不同，沙三Ⅰ型原油分布在洼陷区的沙三中上亚段，成熟度相对较低；沙三Ⅱ型原油分布层位较深，成熟度较高。沙四Ⅰ型原油分布零星，来源于沙四段膏盐间烃源岩。沙四Ⅱ型原油主要来源于沙四段膏盐下烃源岩，多为自生自储型油藏；混源型油气来源于沙三和沙四段烃源岩。油气分布远离油源中心，多位于断阶带上，断层作用对其分布影响明显。

According to the characteristics of saturated hydrocarbon chromatography, GS/MS and biomarker index, combined with the geochemical features of crude oil, the hydrocarbon genetic types and distribution laws of the Bonan Subsag in the Zhanhua Sag have been analyzed based on the comparison of geochemical features of source rocks from different layers of the Shahejie Formation. The research shows that there are 2 suits of hydrocarbon source rocks in the Bonan Subsag, the 3rd member and the 4th member of the Shahejie Formation. The source rocks in the 4th member of the Shahejie Formation can be further divided into evaporate and sub-evaporate ones. All of the source rocks are obviously different in gammacerane content, Pr/Ph ratio and maturity parameters. Oil source correlation indicates that there are 5 types of oil and they have certain laws in distribution. The crude oils of types Ⅰ and Ⅱ in the 3rd member of the Shahejie Formation both originate from the source rocks in the 3rd member of the Shahejie Formation; however, they are obviously different in maturity and distribution. The crude oils of type Ⅰ in the 3rd member of the Shahejie Formation locate in the middle and upper sections of the 3rd member of the Shahejie Formation in the depression, with relatively lower maturity. The crude oils of type Ⅱ in the 3rd member of the Shahejie Formation locate in deeper formations, with relatively higher maturity. The crude oils of type Ⅰ in the 4th member of the Shahejie Formation distribute sporadically, and originate from the evaporate source rocks in the 4th member of the Shahejie Formation. The crude oils of type Ⅱ in the 4th member of the Shahejie Formation come from the sub-evaporate source rocks in the 4th member of the Shahejie Formation, and are mainly self-generated and self-reserved. Mixed oil and gas come from source rocks in both of the 3rd and 4th members, and locate far away from source center influenced by faults, mainly in step-fault zones.

国家科技重大专项（2011ZX05006-003）资助。

https://doi.org/10.11781/sysydz201401033