中阿拉伯盆地油气分布规律和主控因素研究

中阿拉伯盆地是中东油气区油气资源最为富集的盆地。本文以该盆地油气田的最新资料为基础,结合盆地构造-沉积演化过程,应用石油地质综合研究方法,探讨该盆地油气的时空分布特征及主控因素。中阿拉伯盆地内发育3个主要含油气系统:下志留统含油气系统、侏罗系复合含油气系统和白垩系复合含油气系统。中阿拉伯盆地油气的层系分布表现为"下气上油",上二叠统—下三叠统储集层富集了盆地内78.9%的天然气可采储量和83.7%的凝析油可采储量,而上侏罗统—下白垩统则富集了盆地内81.9%的石油可采储量。区域上,中阿拉伯盆地的石油储量主要聚集于西海湾坳陷、迪布蒂巴赫(Dibdibah)坳陷、盖瓦尔(Ghawar)凸起和安纳拉(An N`ala)凸起,天然气和凝析油则在卡塔尔凸起更为富集。中阿拉伯盆地的油气分布主要受3个因素控制:优质区域盖层控制了油气的层系分布,主力烃源岩展布和优势运移路径控制了油气的区域分布,基底断裂和盐运动构成的圈闭控制了油气藏的形成与富集。

Distribution and controlling factors of oil and gas in Central Arabian Basin

The Central Arabian Basin champions both in abundance and enrichment of oil and gas in the Middle East.The present paper focuses some new approaches to the spatio-temporal distribution and controlling factors of the oil and gas in Central Arabian Basin.Three petroleum systems are recognized,including the Lower Silurician petroleum system,Jurassic composite petroleum system and Cretaceous composite petroleum system.Stratigraphically,The Upper Permian-Lower Triassic reservoir rocks are host to 78.9% of recoverable gas reserves and 83.7% of condensate oil reserves in the basin,whereas the Upper Jurassic-Lower Cretaceous reservoir rocks contain 81.9% of recoverable oil reserves in the basin.Regionally,the oil reserves in the basin is enriched mostly in West Gulf depression,Dibdibah depression,Ghawar high and An N＇ala axis,whereas the gas and condensate oil reserves are more enriched in the Qatar Arch.The controlling factors of the hydrocarbons in Central Arabian Basin include the excellent regional cap rocks controlling the stratigraphic distribution of the hydrocarbons; the distribution and favourable migration pathways of the source rocks controlling the regional distribution of the hydrocarbons,and the traps caused by the basement faults and salt movement controlling the accumulation and enrichment of the hydrocarbons in the basin.