准噶尔盆地西北缘中拐—五八区二叠系天然气有利成藏条件及主控因素分析

Favorable Conditions for Forming Permian Gas Reservoirs in Zhongguai 158 Area in Northwestern Margin of Junggar Basin and Their Main Controlling Factors

准噶尔盆地西北缘中拐—五八区西南面紧临玛湖、盆1井西和沙湾三大富生烃凹陷,长期处于油气运移的有利指向区,资源基础好,并存在有利的储盖组合、输导体系、有效圈闭及良好的保存条件,具有天然气成藏的有利条件,进而使该区具备形成中小型气田的可能。结合区内典型气藏分析,指出二叠系佳木河组和上乌尔禾组是该区天然气藏勘探的主要目的层,二叠系地层不整合面、沉积相带以及断裂是影响二叠系天然气成藏的主要因素,二叠系不整合面附近以及二叠系有利的沉积相带是天然气勘探的重要领域。

The southwest of Zhongguai 158 area is next to three major source sags including Mahu Sag,Pen1 Well West Sag,and Shawan Sag.It is long- term in favorable directional zone of hydrocarbon migration and hence has a sound basis at resources.Reservoir-cap assemblages,passage systems, effective traps,and preservation conditions are favorable for forming gas reservoirs.So it is possible to develop medium and small sized gas fields in the area.Based on the analysis of the typical gas reservoirs in the area,Permian Jiamuhe Formation and Upper Wuerhe Formation are taken as main targets for natural gas exploration.Unconformity surfaces,sedimentary facies belts,and faults are main factors that affect gas accumulation of Permian Formation. Favorable sedimentary facies belts near unconformity surfaces of Permian Formation are the main target for natural gas exploration.