南海北部深水区白云凹陷中深层油气成藏过程初探  

Discussion on Hydrocarbon Accumulation Process in Middle-Deep Layers of Baiyun Sag in Deep Water Area of the Northern South China Sea

作　　者：张忠涛 王卓超 陈聪 吴哲 陈淑慧 翟普强 ZHANG Zhongtao;WANG Zhuochao;CHEN Cong;WU Zhe;CHEN Shuhui;ZHAI Puqiang(Shenzhen Branch,CNOOC(China)Ltd.,Shenzhen,Guangdong 518054,China;Deepwater Development Co.,Ltd.,CNOOC,Shenzhen,Guangdong 518054,China)

机构地区：[1]中海石油(中国)有限公司深圳分公司,广东深圳518054 [2]中海石油深海开发有限公司,广东深圳518054

出　　处：《西安石油大学学报（自然科学版）》2023年第2期43-52,共10页Journal of Xi’an Shiyou University（Natural Science Edition）

基　　金：国家重大专项(2016ZX05026-003-008);中海油有限公司重大项目(KJZH-2021-0003-00)。

摘　　要：珠江口盆地深水区白云凹陷具有极为特殊的油气地质条件,近几年,在中深层渐新统珠海组及下伏始新统恩平组见到了规模且连续分布的气层,并具有超压特征,其研究对白云凹陷中深层油气富集规律的认识和勘探实践有重要意义。目前由于受样品等资料少的限制,对其油气成藏过程的研究非常薄弱。通过白云凹陷深层超压的研究,认为其成因为生烃增压传导所致,说明白云凹陷具有极强的生烃能力,同时由于超压封闭原因,大部分油气应被封存在超压箱内。在此基础上,对B-2低渗超压气藏进行解剖,运用天然气地球化学与成藏动态研究方法,在明确天然气成因、成熟度及来源的基础上,分析天然气充注期与储层孔隙、压力演化的关系,解析该低渗气藏成藏过程。研究认为,珠海组下段-恩平组大型三角洲沉积“甜点”储层分布区与具备“原油早期充注-储层低渗化-超压-天然气晚期充注”型成藏过程的叠合区,是有利勘探区带,为白云凹陷中深层勘探指明了一定方向。The petroleum geology is unique in Baiyun Sag locating in deepwater area of Pearl River Mouth Basin.For a long time,the research of hydrocarbon accumulation in this area is little due to limited drilled holes and other reasons.However,in the exploration practice in recent years,large-scale and continuous gas layers with overpressure characteristics have been found in the middle-deep Oligocene Zhuhai Formation and the underlying Eocene Enping Formation,which is of great significance to the recognization of oil and gas enrichment law and exploration practice in the middle-deep layers of Baiyun Sag.Through the study of deep overpressure in Baiyun Sag,it is held that the overpressure is caused by the conduction of hydrocarbon generation pressurization,indicating that Baiyun Sag has strong hydrocarbon generation capacity,and the most of hydrocarbon should be sealed in the overpressure box.Based on this,the B-2 low permeability overpressure reservoir is anatomized,and the relationship between the natural gas filling period and the evolution of reservoir pore and pressure is analyzed using the natural gas geochemical and hydrocarbon accumulation dynamic research methods on the basis of determining the origin,maturity and source of natural gas,and the hydrocarbon accumulation process of the low permeability gas reservoir is analyzed.It is shown that the distribution area of"sweet spot"reservoirs in large delta sedimentation in the lower section of Zhuhai Formation to Enping Formation is overlapping with the hydrocarbon accumulation process of"early filling of crude oil-low permeability of reservoir-overpressure-late filling of natural gas",and it is favorable exploration zone,which indicates a certain direction for the oil and gas exploration in the middle and deep layers of Baiyun Sag.

关 键 词：白云凹陷深水区 超压低渗气藏 生烃增压 成藏过程 

分 类 号：TE122[石油与天然气工程—油气勘探]