中阿拉伯盆地Khuff—Sudair组油气藏地质特征及成藏模式

Geological Characteristics and Hydrocarbon Accumulation Model of the Upper Paleozoic Khuff-Lower Mesozoic Sudair Play in the Central Arab Basin

Khuff—Sudair组油气成藏组合是中阿拉伯盆地重要的油气成藏组合。通过对该成藏组合古地理演化、烃源岩、储集层、盖层、成藏过程和模式的分析认为,下志留统Qusaiba段烃源岩于中侏罗世卡洛夫期开始生油,早白垩世土仑期开始生气;生成的油气通过断层、裂缝垂直运移和上覆地层砂岩水平运移到上二叠统Khuff组储集层内;下三叠统Sudair组提供了有效的区域盖层;由于石油的生成和排烃早于圈闭的形成,所以很难聚集成藏,而天然气的生成和排烃时间与圈闭的形成时间一致,所以天然气在基底活动形成的构造圈闭中聚集成藏。目前世界最大的天然气田North-South Pars气田特有的Khuff—Sudair组油气成藏组合是中阿拉伯盆地今后油气勘探的重点。

The Khuff-Sudair play is an important play in Persian Gulf Basin. This paper studied the paleogeography evolution, hydrocarbon source rocks, reservoir rocks, cap rocks and hydrocarbon accumulation process and model of the Khuff-Sudair play. The Lower Silurian Qusaiba source rock was deposited in anoxic marine shelf in fast subsiding depo-center of Arabian platform. Its source rock went into oil window in the Callovian period of Late Middle Jurassic and into gas window in the Early Cretaceous-Turonian period. The oil and gas migrated vertically through faults and fractures and horizontally through overlying sandstone into the Khuff reservoir of the Upper Permian. The Sudair formation of Lower Triassic provided an effective regional seal. The time of oil generation and expulsion was earlier than the time of trap formation, so the oil was difficult to accumulate. The time of gas generation and expulsion was at the same time with the trap formation, so the gas accumulation occurred in the structural trap formed by the basal activity. The Upper Paleozoic Khuff-Lower Mesozoic Sudair play in the North-South Pars gas field could be a major target for petroleum exploration in the Mid-Arab ersian Gulf basin in the future.