摘要
珠江口盆地东部在珠江组早期,沿东沙隆起一带发育碎屑岩-碳酸盐混合沉积.混合沉积类型主要包括组分混合和地层混合等,且混合沉积与岩性油气藏关系密切,统计资料表明,94%已发现岩性油气藏都分布于该混合沉积区.区内岩性油气藏储层岩性为碎屑岩,封堵岩性则为泥岩、混积岩或碳酸盐.分析认为,该类型岩性油气藏的有利地质条件包括:陆相湖盆提供的巨量烃源岩、古珠江物源形成的三角洲和深水扇体系作为优质储层、碎屑岩-碳酸盐混积区特有的低含砂率利于岩性圈闭侧向和垂向封堵、晚期构造活动与继承性构造脊利于油气运移保存等.结合勘探实践,认为在混合沉积区开展岩性勘探应以富生烃凹陷作为含油气系统的分析单元,重点寻找不同沉积体系混合沉积区内的碎屑岩砂体.进而将研究区划分为3大含油气系统,并确定4大有利岩性油气聚集带.
Mixed siliciclastic-carbonate developed around Dongsha massif in early Zhujiang Formation,with the mixing types divided into compositional mixing and strata mixing.The statistic data show that the development of lithological reservoir is closely related with the distribution of mixed-sedimentation area,as 94%of the discovered lithological reservoirs are concentrated in mixed-sedimentation area.Oil and gas are accumulated in sand rocks and sealed by mud rocks or mixed rocks in lithological reservoirs.The key geological factors on lithological reservoir are studied,showing that the formation condition of lithological reservoir was controlled by terrestrial lakes,sand rocks were sourced from paleo-Pearl River,and seal rocks formed in mixed siliciclastic-carbonate sedimentation zone for its low sand ratio as the result of distal provenance,late tectonic activity and inherited structural ridges.Furthermore,integrated with oil accumulation analysis,it is suggested that lithological exploration should be focused on petroliferous sags,and centered on siliciclastic reservoirs in mixed sedimentary zone,on basis of which 3 hydrocarbonbearing systems and 4 favorable zones are figured out in the study area.
作者
梁卫
李小平
Liang Wei;Li Xiaoping(Shenzhen Branch of China National Offshore Oil Corporation Limited,Shenzhen 518067,China)
出处
《地球科学》
EI
CAS
CSCD
北大核心
2020年第10期3870-3884,共15页
Earth Science
关键词
珠江口盆地
混合沉积
岩性油气藏
勘探潜力
沉积
Pearl River Mouth basin
mixed sedimentation
lithological reservoir
exploration potential
sedimentation
