南海北部边缘盆地油气主要成因类型及运聚分布特征

Main Genetic Types of Oil & Gas and Characteristics of Their Accumulation and Distribution in North Marginal Basins,South China Sea

南海北部边缘盆地处在欧亚、印—澳及太平洋三大板块交汇处,区域地质背景特殊,第三系沉积发育,油气地质现象丰富多彩,油气成因类型及分布规律复杂。根据南海北部边缘盆地油气勘探及研究程度,迄今为止所发现的油气可以划分为生物气及生物—低熟过渡带气(亚生物气)、热成因正常成熟油气和高熟—过熟油气等3大类7亚类,CO2等非烃气可划分为3型4类,其中成熟陆源石蜡型油气主要分布于北部湾、珠江口盆地,成熟—高熟煤成凝析油气主要分布于琼东南盆地西部及珠江口盆地部分地区,煤成气及CO2等非烃气则主要运聚于莺歌海盆地泥底辟带浅层、琼东南盆地东部和珠江口盆地部分地区。

The north marginal basins of South China Sea are located at the junction of the Eurasian, the Pacific Ocean and the Indian-Australian plates. The geological setting is complex, the Tertiary sediment developed well, and petroleum geological phenomena are rich and colorful. Based on the previous research and exploration, the discovered oil and gas can be divided into three types, biogenic and sub-biogenic gas, normal mature oil ＆gas, highly and over-mature oil ＆ gas. And there are also three types of non-hydrocarbon gas. The normal mature continental paraffin oil ＆ gas are mainly distributed in the Beibuwan Basin and the Pearl River Mouth Basin. The highly and over-mature coal-related condensate gas oil ＆ gas are mainly found in the Qiongdongnan Basin and some areas of the Pearl River Mouth Basin. Coal-related gas and non-hydrocarbon gas are mainly formed in mud diapiric zones of the Yinggehai Basin, the Eastern Qiongdongnan Basin and some areas of the Pearl River Mouth Basin.