准噶尔盆地中拐凸起南部佳木河组储层发育特征及演化序列OA

The Lower Permian Jiamuhe Formation in the south of Zhongguai Uplift is an important pe-troleum exploration hotspot of the deep-ultra-deep tight sandstone(conglomerate)in the northwestern margin of Junggar Basin.The reservoir petrology,reservoir physical properties and reservoir space de-velopment characteristics are characterized by using core thin section,high pressure mercury injection,SEM and core three-dimensional CT scanning,and reservoir control factors and evolution process are discussed.The results show that:the reservoir lithology in the study area is dense conglomerate rich in laumontite cement,which has the characteristics of medium-high porosity and low permeability.The reservoir space is dominated by late dissolution pores.The pore throat coordination number and the pore connectivity are bad.Fan delta front is the main facies belt of reservoir development.Compaction and cementation lead to reservoir densification.The dissolution of laumontite is the main internal factor of tight reservoir accumulation.The tectonic effects such as faults and unconformities affect the elimina-ting densification process of reservoirs by enhancing the breadth and depth of dissolution.Affected by tectonic uplift leaching and source rock evolution,the reservoir was modified by three stages of dissolu-tion:weak acid water on the surface,organic acid in the early stage of hydrocarbon expulsion and partial pressure rise of CO2 with crude oil cracking in the over-mature stage.Among them,the leaching of weak acid water on the surface is the main reason for reservoir eliminating densification.The results provide a reference for the exploration and development of the study area and the same type of reservoir.