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Khuff组成藏组合是波斯湾盆地最重要的天然气成藏组合,二叠系Khuff组储层和层间硬石膏盖层构成了成藏组合的基本要素。下志留统Qusaiba段热页岩是Khuff组成藏组合的烃源岩,其分布广、有机质含量高,在晚白垩世大面积成熟生烃,而大部分圈闭形成早于主生烃期,且基底断裂发育,充当了烃类由Qusaiba段热页岩向Unayzah组砂层运移的垂向通道,Unayzah储层充当了主要的油气平面运移通道;面积广阔、沉积相稳定的Khuff组内碳酸盐岩和硬石膏旋回层序既提供了储层,也提供了成藏组合内绝大部分气田的优质盖层。同时,储层的原始物性好,鲕粒、球粒、生物泥粒灰岩及粒屑灰岩都具有很好的印模孔隙和粒间孔隙,此外,后期的淋滤作用加上白云岩化产生的晶间孔隙极大地改善了储层的质量。在大部分区域内,后期断层活动并没有破坏盖层的封闭性,天然气资源的散失量小。Khuff组成藏组合的未来勘探地区主要分布在Qusaiba段烃源岩的成熟区内,最有潜力的地区为层间硬石膏与Qusaiba段烃源岩成熟区重合的部分,包括波斯湾水域、波斯湾西北部及加瓦尔油田以南地区。大型低幅度构造的识别是将来的重点工作之一,同时,由于中东地区油气勘探生产的经济门限较高,相对较小规模的油气藏的开发要依赖高气价的推动作用。
The Khuff Formation is the most important gas reservoir assemblage in the Persian Gulf basin. Permian Khuff Formation and intergranular anhydrite cap formations constitute the basic elements of the reservoir assemblage. The Lower Silurian Qusaiba section shale is a source rock of the Khuff formation and assemblage. It has a wide distribution, high organic matter content and large-area mature hydrocarbon generation in the Late Cretaceous, with most of the traps formed earlier than the main hydrocarbon generation period. And the basement faulting develops. It acts as a vertical channel for hydrocarbons migrating from the Qusaiba section to the Unayzah Formation sandstone. Unayzah reservoir serves as the major channel for hydrocarbon migration. The Khuff Formation, with a large area and stable sedimentary facies, Carbonate and anhydrite gyration sequences provide both reservoirs and good cap formations for the vast majority of gas fields in the reservoir assemblage. At the same time, the reservoir has good original properties. Both ooids, pellets, biolayered limestone and granulitic limestone have good impression porosity and intergranular porosity. In addition, the later leaching and dolomitization The resulting intergranular porosity greatly improves the quality of the reservoir. In most areas, the late fault activity did not destroy the caprock closure and the loss of natural gas resources was small. The future exploration area of the Khuff assemblage is mainly located in the mature area of the Qusaiba source rock. The most promising area is the overlap between the interlayer anhydrite and the mature area of the Qusaiba source rock, including the Persian Gulf waters, the Persian Gulf Northwest and Gavar oilfield south of. Large-scale low-amplitude structural identification is one of the key tasks in the future. At the same time, due to the high economic threshold of oil and gas exploration and production in the Middle East, the development of relatively small-scale reservoirs depends on the promotion of high gas prices.