珠江口盆地东沙隆起混合沉积特征及勘探潜力

Mixed sedimentary characteristics and exploration potential of Dongsha Uplift in Pearl River Mouth Basin

新近系中新统珠江组下段是珠江口盆地东沙隆起主要的油气勘探层段之一,且广泛发育混合沉积,前人主要以陆源碎屑沉积体系开展相关研究。依据录井、岩心和薄片鉴定等资料,同时结合区域油气地质背景,对混合沉积特征、成因、主控因素等进行了系统研究,详细阐述了研究区早中新世的混合沉积格局及成因模式。研究区主要发育混积潮坪相,混合沉积在微观上表现为陆源碎屑与碳酸盐组分上的混积岩,宏观上表现为混积岩、陆源碎屑岩和碳酸盐岩互层的混积层序。混积机理与海平面、物源和水动力条件等的频繁变化密切相关,混积方式以原地混合和相混合为主,见风暴成因的间断混合。通过混合沉积特征、控制因素、成藏潜力等研究,为研究区下一步油气勘探提供了支持。

The lowest member of the Neogene Miocene Zhujiang Formation is one of the primary oil and gas exploration intervals in the Dongsha Uplift of the Pearl River Mouth Basin.And mixed sediments have been widely formed.Terrigenous clastic sedimentary systems have been the main subject of previous studies.A systematic study was conducted on the mixed sedimentary characteristics,genesis,and main controlling factors based on the data from mud logging,core,and thin section identification,combined with the regional oil and gas geological background.The mixed deposition pattern and genetic model of the early Miocene in the study area were described in detail.In the research area,the mixed tidal flat facies is primarily established.The mixed sediments are represented macroscopically as mixed sequences of interbedded dialites,terrigenous clastics,and carbonates,and microscopically as dialites of terrigenous clasts and carbonate components.frequent changes in sea level,provenance,hydrodynamic conditions,etc.are all closely related to the mixing mechanism.The predominant mixing modes are in-situ mixing and facies mixing,with storm-induced intermittent mixing.Further oil and gas exploration in the region may be supported by studies of mixed sedimentary characteristics,controlling variables,reservoir formation potential,etc.