判别分析油源对比方法及应用——以渤海湾盆地渤中凹陷为例  

Discriminant analysis-based oil-source correlation method and application:A case study of Bozhong depression in Bohai Bay basin

作　　者：周姗姗 李友川 杨树春 兰蕾 李建平 ZHOU Shanshan;LI Youchuan;YANG Shuchun;LAN Lei;LI Jianping(CNOOC Research Institute Ltd.,Beijing 100028,China)

机构地区：[1]中海油研究总院有限责任公司,北京100028

出　　处：《中国海上油气》2023年第5期35-46,共12页China Offshore Oil and Gas

基　　金：中海石油(中国)有限公司综合科研“油气三维运移动态成藏关键技术研究(编号:KJZH-2023-2105)”部分研究成果。

摘　　要：渤海湾盆地发育多套优质湖相烃源岩,不同烃源岩地球化学特征相似,油源对比难度大。针对常规油源对比方法无法有效区分不同湖相烃源岩的问题,以渤中凹陷为研究靶区,引入判别分析油源对比方法,利用108件烃源岩样品建立判别模型,判识了115个原油样品的油源,并结合成藏条件对判别结果进行合理性探讨。研究表明,利用判别分析方法筛选出的C_(19)/C_(23)三环萜烷、C_(21)/C_(23)三环萜烷、ααα-C_(29)甾烷(20R)/C_(30)藿烷等17个生物标志化合物参数组合,可以在多维空间有效区分渤中凹陷沙三段、沙一段和东三段3套湖相烃源岩;判别分析油源对比模型初始验证正确率达92.6%,交叉验证正确率达83.3%,提高了油源对比可靠性。该油源对比方法不仅适用于渤中凹陷,也可推广应用至其他多源供烃的含油气盆地。The Bohai Bay basin is characterized by the presence of multiple sets of high-quality lacustrine source rocks with similar geochemical characteristics,posing challenges in distinguishing different lacustrine source rocks for oil-source rock correlation.In this research,a discriminant analysis-based oil-source rock correlation method was introduced to address the limitation of conventional oil-source rock correlation methods in effectively distinguishing between various lacustrine source rock formations.A discriminant model was established by utilizing analytical test data from108 source rock samples,enabling the identification of oil sources for 115 crude oil samples within the Bozhong depression.The rationality of the discrimination results was evaluated in conjunction with the trapping conditions.The results show that a combination of 17 biomarker compound parameters,including C_(19)/C_(23)tricyclic terpanes,C_(21)/C_(23)tricyclic terpanes,ααα-C_(29)sterane(20R)/C_(30)hopane,etc.,selected by discriminant analysis,can effectively differentiated the three sets of lacustrine source rocks,namely,Sha-3,Sha-1,and Dong-3,within the Bozhong depression in a multidimensional space.The model achieved a high correct discrimination rate using original validation(92.6%)and leave-one-out cross-validation(83.3%),significantly improving the reliability of oil-source rock correlation.This oil-source rock correlation method is not only applicable to the Bozhong depression but also has the potential to be extended to other hydrocarbon-bearing basins with multiple sources of hydrocarbon generation.

关 键 词：渤海湾盆地 渤中凹陷 油源对比 判别分析 生物标志化合物 混源油 

分 类 号：TE121.3[石油与天然气工程—油气勘探] P744.4[天文地球—海洋科学]