南海油气分布特征及主控因素探讨

以最新油气田储量数据为基础,运用统计学与石油地质综合分析相结合的方法,研究表明,南海以气为主,其油、气探明储量分别占总探明储量的38%和62%。总探明储量中:碎屑岩储层油气田所占比例最高,占57%;其次为生物礁碳酸盐岩储层油气田,占36%;前第三系基岩裂缝型储层油气田,占7%。碎屑岩储层油气田主要分布于近物源区域,生物礁储层油气田主要分布于远离物源的台地区,基岩裂缝型储层油气田主要分布于南海西部走滑带控制的盆地中。油气主要分布于中中新统,其次为下中新统与前第三系基岩,它们分别占总探明储量的51%、17%和11%。高地温梯度与烃源岩的有机质类型决定了南海油气资源以气为主,盆地类型的差异决定了南海南部油气资源较北部丰富。盆地构造演化史和周边古水系控制了南海油气田储集类型和时空分布。

Characteristics and Controlling Factors of Hydrocarbon Distribution in South China Sea

The last statistic data for reserves in offshore fields have shown that natural gas is more than oil in South China Sea.Proved oil reserves and gas reserves take up 38% and 62% respectively of the total.Among the total proved reserves,the reserves in clastic reservoirs occupy 57%,the ones in carbonate reservoirs do 36% and the ones in pre-Tertiary fractured bedrock reservoirs are 7% of the total.The fields of clastic reservoirs are commonly located in the areas near sediment source.The ones of carbonate reservoirs are mainly distributed in the platform areas away from the sediment source.The ones of pre-Tertiary bedrock reservoirs are mostly in strike-slip basins that are located at the west margin of the sea.The proved reserves distribute respectively in the Miocene rocks(51%),in the Lower Miocene rocks(17%) and in the pre-Tertiary bedrocks(11%).High geothermal gradient and the types of organic matter in source rocks are the reasons that gas is richer than oil in resource and the different types of basins decide that resource is richer in the southern part of the sea than in the northern part of it.The tectonic history and the peripheral paleo-river system controls the reservoir types of fields and temporal and spatial distribution of fields.