珠江口盆地白云凹陷北坡—番禺低隆起油气来源及成藏分析

过去一直认为珠江口盆地白云凹陷北坡-番禺低隆起油气为文昌组和恩平组烃源岩混合来源。在前人研究基础上做了进一步的研究工作,包括重新大量取样,应用前人在白云凹陷烃源研究中尚未用过的分析技术(如热解吸附烃分析方法、异构烷烃GC/MS技术、单体烃同位素分析技术等)分析样品,根据新资料进行综合分析等。综合研究认为:番禺低隆起油气主要源自恩平组烃源岩,没有文昌组中深湖相烃源岩的贡献;研究区没有发现文昌组油气是由于文昌组烃源岩主要生烃期与白云凹陷北坡-番禺低隆起圈闭形成期、油气成藏期匹配不好所致;白云凹陷北部生气南部生油,白云主洼南部以及白云凹陷南部地区是文昌组油气的有利聚集区,应是下一步勘探方向。

An analysis of hydrocarbon source and accumulation in Panyu low-uplift and north slope of Baiyun sag, Pearl River Mouth basin

It has been known that the hydrocarbon in Panyu low-uplift and north slope of Baiyun sag has a mixed source of Wenchang and Enping Formations.A further study based on previous results was conducted,including a large size of resampling,an application of analytical techniques that have not been used previously in hydrocarbon study in Baiyun sag(such as pyrolytic analysis of adsorbed hydrocarbon,GC/MS technique of isoalkane,and monomer hydrocarbon isotope analysis),and a comprehensive analysis based on new data.The study results show that hydrocarbon in Panyu low-uplift is mainly derived from Enping Formation and is not contributed by deep lacustrine source rocks in Wenchang Formation.Furthermore,the reason why no hydrocarbon derived from Wenchang Formation is found in the study area may be the absence of match of the main hydrocarbon-generation stage of Wenchang Formation source rocks,the forming stage of traps in Panyu low-uplift and north slope of Baiyun sag and the hydrocarbon accumulation stage.Because gas is generated in the northern Baiyun sag,and oil in the southern sag,the south part of Baiyun main subsag and the southern sag are favorable accumulation areas of Wenchang Formation hydrocarbon,and should become the targets of further exploration.