珠江口盆地白云凹陷原油中典型生物标志化合物组合及其地球化学意义

Biomarker compositions and geochemical significance of crude oils of Baiyun Sag, Pearl River Mouth Basin

冉子超 李美俊 李友川 时阳 王宁 杨永才 卢晓林 肖洪

RAN Zichao LI Meijun LI Youchuan SHI Yang WANG Ning YANG Yongcai LU Xiaolin XIAO Hong

中国石油大学(北京) 油气资源与探测国家重点实验室，地球科学学院，北京 102249 长江大学 油气资源与勘探技术教育部重点实验室，资源与环境学院，武汉 430100 中海油研究总院有限责任公司，北京 100027 中国石油 南方石油勘探开发有限责任公司 勘探开发研究中心，海口 570216 中海油能源发展股份有限公司 工程技术分公司 中海油实验中心(深圳)，广东 惠州 516000

State Key Laboratory of Petroleum Resources and Prospecting, College of Geosciences, China University of Petroleum (Beijing), Beijing 102249, China Key Laboratory of Exploration Technologies for Oil and Gas Resources, Ministry of Education, College of Resources and Environment, Yangtze University, Wuhan, Hubei 430100, China CNOOC Research Institute Company Limited, Beijing 100027, China Exploration and Development Research Center of PetroChina South Petroleum Exploration and Development Co., Ltd., Haikou, Hainan 570216, China CNOOC Experimental Center of Engineering Technology Branch of CNOOC Energy Development Co., Ltd. (Shenzhen), Huizhou, Guangdong 516000, China

珠江口盆地白云凹陷原油中富含新C15倍半萜烷、特殊构型的三环萜烷和四环萜烷(X、Y、Z和X1、Y1、Z1)及双杜松烷等指示陆源高等植物有机质输入的典型生物标志化合物以及常见的指示被子植物有机质输入的生物标志化合物奥利烷。基于白云凹陷13件原油样品饱和烃色谱质谱分析结果，对原油中典型生物标志化合物的组成及其地球化学意义进行了探讨。研究表明，降A-奥利烷(Y1)和C27四环萜烷(Z1)可能具有相同的生物来源；而根据相关化合物分子结构及各区域丰度相关性分析，判断出新C15倍半萜烷、降A-奥利烷和C27四环萜烷及双杜松烷可能具有不同的生源或演化过程。另外，不同区域原油的生物标志化合物组成差异明显。这些生物标志化合物是研究区原油族群划分的良好指标。经分析，双杜松烷与新C15倍半萜烷的分布受到沉积环境的影响较大，可能更富集于偏氧化的沉积环境；降A-奥利烷、C27四环萜烷和奥利烷的分布主要受到生源的影响，而受沉积环境影响较小。白云东北、东区原油降A-奥利烷、C27四环萜烷和奥利烷相对丰度明显偏高，这在一定程度上反映了位于白云东部的东沙隆起和云荔低隆起可能是研究区陆源有机质的重要来源地。

Crude oils from the Baiyun Sag of Pearl River Mouth Basin have high abundance of diagnostic biomarkers including novel C15 sesquiterpene, special configurated tricyclic sesquiterpenes and tetracyclic sesquiterpenes (X, Y, Z and X1, Y1, Z1), and bicadinanes, which indicate the contributions from terrestrial higher plants to the organic matters. These oils are also rich in oleanane, which is a diagnostic biomarker for angiosperm organic matter. Based on the analysis of 13 crude oils from the Baiyun Sag, the compositions and geochemical significance of typical biomarkers were revealed. Results indicate that C24-des-oleanane (Y1) and C27 tetracyclic (Z1) may share a similar biological origin. Novel C15 sesquiterpene, C24-des-oleanane and C27 tetracyclic, and bicadinanes may be derived from different higher plants according to the molecular structure and abundance correlation analysis of the related compounds. In addition, the biomarker compositions of crude oils from different regions are significantly varied, which will benefit the oil group classification in the Baiyun Sag. The distribution of novel C15 sesquiterpene and bicadinanes was influenced by sedimentary environment, and may be more enriched in oxidized environment. The distribution patterns of C24-des-oleanane, C27 tetracyclic and oleanane are principally affected by biogenic input, but are less influenced by sedimentary environment fluctuation. The relatively high abundance of C24-des-oleanane, C27 tetracyclic and oleanane in the crude oil in the northeastern and eastern Baiyun area reflects that the Dongsha Uplift and the Yunli Low Uplift may be an important source of terrigenous organic matter in this area.

中海石油(中国)有限公司北京研究中心与中国石油大学(北京)的合作项目“白云凹陷有效烃源岩灶研究” CCL2020RCPS0039ESN

https://doi.org/10.11781/sysydz2022061059