番禺低隆起—白云凹陷北坡超晚期天然气成藏特征

CHARACTERISTICS OF ULTRA-LATE GAS RESERVOIRING IN PANYU LOW SWELL,NORTHERN SLOPE ZONE OF BAIYUN SAG

中海油近期在南海北部深水区白云凹陷的深水天然气勘探取得了重大突破,对开辟我国深水油气勘探新领域具有重要意义。通过构造发育史分析以及对典型气藏的解剖,论证了珠江口盆地番禺低隆起—白云凹陷北坡天然气藏属典型超晚期成藏。对该区气藏形成地质条件的研究表明:新近纪以来白云凹陷一直处于主生、排烃期以及东沙运动引起的断裂活动,是该区超晚期成藏形成的2个必要条件,二者的相互匹配则是超晚期成藏的充要条件。进而对该区提出勘探建议:以断层为依托、以超晚期油气平面运移路径为指向,寻找有利保存条件区。

A major breakthrough of gas exploration has been made recently by CNOOC in Baiyun sag located in the northern deep water of South China Sea.It is of great significance for opening up deep water frontiers in China.An analysis of the structural history and a detailed study of typical gas reservoirs show that the gas pools are characterized by ultra-late reservoiring in Panyu low swell-northern slope zone of Baiyun sag,the Pearl River Mouth Basin.A study of the geological conditions of gas reservoiring in the study area reveals that the peak hydrocarbon generation and expulsion in Baiyun sag since Neogene and the faulting resulted from Dongsha movement are two necessary conditions for ultra-late reservoiring in the study area,while their timing is the adequate condition.Concerning exploration in the study area,it is proposed to search for areas with favorable preserving conditions based on recognition of faults and ultra-late lateral hydrocarbon migration pathways.