库车前陆盆地大北地区盐下致密砂岩储层具有埋藏深度大、低孔和低渗的特征,以产气为主并伴生少量的轻质原油.在对大北地区盐下致密砂岩储层特征、油气成熟度、油气充注史研究基础之上,结合致密砂岩孔隙演化特征综合分析油气充注与储层致密化的时间关系.大北地区盐下致密砂岩储层孔隙空间主要以次生溶蚀孔为主,大部分孔隙空间都被沥青充填,由孔隙和沥青组成的空间网络具有较好的连通性,压实作用为储层致密化重要成因,碳酸盐胶结作用应该主要在库车组沉积之前使孔隙度降低.致密砂岩储层中发育沥青,油气地球化学特征以及流体包裹体分析结果均表明库车前陆盆地大北地区致密砂岩储层存在两期油和一期天然气充注.晚期原油充注发生在距今5~4Ma,对应库车组沉积早期,天然气充注发生在距今3~2Ma,对应地层抬升剥蚀时期.库车前陆盆地大北地区盐下砂岩储层在油充注时期埋藏深度较浅,具有较高的孔隙度,而天然气充注时期,砂岩储层已经遭受了强烈的压实作用达到了致密化程度. The tight sandstone reservoirs in the Dabei area of ​​the Kuqa foreland basin have the characteristics of large buried depth, low porosity and low permeability, and are mainly gas-producing and associated with a small amount of light crude oil. Based on the previous studies on the characteristics of oil and gas evolution, the relationship between the filling of oil and gas and the densification of reservoir, the pore space of the tight sandstone reservoir in the Dabei area is mainly divided into The pores are mostly filled with bitumen, and the space network composed of pores and bitumen has good connectivity. Compaction plays an important role in the densification of the reservoir. The carbonate cementation should be mainly in the reservoir The porosity of the car group decreases before sedimentation.The developed bitumen in the tight sandstone reservoirs, the geochemical characteristics of oil and gas and the analysis of fluid inclusions show that there are two phases of oil and one phase of natural gas in the tight sandstone reservoirs in the Dabei area of ​​the Kuqa foreland basin Note that the late charge of crude oil occurred 5 ~ 4Ma ago, corresponding to the early deposition of the Kuqa Formation, and the filling of natural gas occurred within 3 ~ 2Ma, corresponding to the uplift and erosion period of the strata. The Kuqa foreland basin Dabei area Under-salt sandstone reservoirs are shallow buried during oil filling period and have high porosity. During natural gas filling, sandstone reservoirs have undergone strong compaction and reached the degree of densification.