白云凹陷文昌组湖相烃源岩油源贡献再认识  

Reassessment of oil contribution of lacustrine source rocks to Wenchang Formation in Baiyun Sag

作　　者：杨永才 杨东升 谢晓军 黄胜兵 王升兰 杨树春 兰蕾 王柯 林青 郝建荣 YANG Yongcai;YANG Dongsheng;XIE Xiaojun;HUANG Shengbing;WANG Shenglan;YANG Shuchun;LAN Lei;WANG Ke;LIN Qing;HAO Jianrong(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》2025年第2期82-90,共9页China Offshore Oil and Gas

基　　金：国家自然科学基金企业创新发展联合基金重点支持项目“南海北部深水区深层温压场差异性演化对优质储层的控制机理(编号:U24B2016)”;国家自然科学基金项目“南海深海地质演变对油气资源的控制作用(编号:91528303)”;“十三五”国家科技重大专项“大型油气田及煤层气开发(编号:2016ZX05026)”;国家重点基础研究发展计划(973)项目“南海深水盆地油气资源形成与分布基础性研究(编号:2009CB219400)”。

摘　　要：珠江口盆地白云凹陷是南海北部深水区主要勘探领域,已发现22个油气田,但原油的主力油源贡献长期存在争议。借鉴邻区珠一坳陷文昌组烃源岩沉积相特征,同时结合地球化学特征,对白云凹陷已发现原油开展了文昌组湖相烃源岩油源判识的精细研究。研究表明:(1)白云凹陷原油主要划分为2类,A类原油具有高双杜松烷、低奥利烷、低4-甲基甾烷的典型特征,B类原油具有低双杜松烷、中低奥利烷,低4-甲基甾烷;(2)A类原油为恩平组上段煤系烃源岩生成的原油,B类原油主要来源于恩平组上段陆源海相烃源岩生成的原油,可能具有文昌组滨湖相烃源岩、恩平组中下段滨浅湖相烃源岩的油源贡献;(3)白云主洼文昌组半深湖—深湖相烃源岩对白云凹陷主洼原油的油源贡献很小;(4)环白云主洼的周缘凹陷具有发育文昌组半深湖—深湖相优质烃源岩地质条件,并且具有油气来源贡献的佐证。本研究为南海北部深水区白云南洼等原油勘探的有利新领域优选提供依据。Baiyun Sag in the Pearl River Mouth Basin is the main exploration region in the deep-water areas of the northern South China Sea,where 22 oil and gas fields have been discovered.However,for a long time,the major source contribution of crude oil has been controversial.Based on the combination of sedimentary facies characteristics of hydrocarbon source rocks of Wenchang Formation in ZhuⅠDepression and the geochemical characteristics,this paper carried out a detailed study on the oil source identification of the lacustrine hydrocarbon source rocks of Wenchang Formation.The results are as follows:①The crude oil in Baiyun Sag is mainly divided into two categories.Specifically,category A crude oil typically features high dicadinanes,low oleanane,and low 4-methylsteranes,while category B crude oil has low dicadinanes,medium-low oleanane,and low 4-methylsteranes.②Category A is derived from the coal-bearing source rocks of the upper member of the Enping Formation,while category B mainly comes from the terrestrial marine source rocks of the upper member of the Enping Formation,and may have oil source contributions of shore-shallow lacustrine hydrocarbon source rocks of Wenchang Formation and the middle and lower members of Enping Formation.③The semi-deep and deep lacustrine source rocks of the Wenchang Formation in the Baiyun main sag contribute little to the oil source of the main Baiyun sag.④The peripheral sub-sags around the main Baiyun sag have geological conditions for developing high-quality source rocks of semi-deep and deep lacustrine facies in the Wenchang Formation,with evidence showing the contribution of oil and gas sources.This study provides a basis for the selection of new favorable oil exploration areas such as the southern Baiyun sub-sag in the deep-water areas of the northern South China Sea.

关 键 词：半深湖—深湖相 4-甲基甾烷 油源对比 白云凹陷 珠江口盆地 

分 类 号：TE122.1[石油与天然气工程—油气勘探] P744.4[天文地球—海洋科学]