中江沙溪庙组致密砂岩气藏气水分布及主控因素

为明确中江沙溪庙组深源浅聚型致密砂岩气藏气水分布规律及主控因素，应用岩芯分析、测井、试气、生产、核磁共振和地层水化学分析等资料，对地层水的微观赋存状态、宏观分布规律及主控因素进行了研究。结果表明，中江沙溪庙组地层水矿化度为III$\sim$V类CaCl$_2$型地层水，地层水以束缚水和毛细管水的形式赋存于储层中，宏观上气水分布受断砂配置、局部构造和河道内部非均质性控制。断层既是天然气充注的基础，又是散失的通道，控制着气、水的宏观分布特征；近断层处天然气易散失，以气水同层为主。河道内部非均质性和局部构造共同控制气、水的局部分布特征，其中，河道内部发育的岩性（物性）封堵能阻止天然气向高部位断层处的运移和散失，并使得气水呈“香肠式”分布，构造低部位也可见气层发育。无岩性封堵河道气水呈“上气下水”分布模式，局部构造高部位为气层，构造相对低部位为水层或气水同层。

Gas and Water Distribution and Main Controlling Factors of Tight Sandstone Gas Reservoir in Shaximiao Formation,Zhongjiang

In order to clarify the gas-water distribution law and main controlling factors of Shaximiao Formation deep source shallow accumulation tight sandstone gas reservoir in Zhongjiang. Based on the data of core analysis, well logging, gas test, production, nuclear magnetic resonance and formation water chemical analysis, the microscopic occurrence state, macroscopic distribution law and main controlling factors of formation water are studied. The results show that the formation water salinity of Shaximiao Formation is CaCl$_2$ type III$\sim$V, and the formation water exists in the reservoir in the form of bound water and capillary water. The distribution of gas and water is controlled by faults, local structures and internal heterogeneity of channels. Fault is not only the basis of gas charging, but also the passage of loss, which controls the macroscopic distribution characteristics of gas and water. Fractures develop in the near fault layer, and natural gas is dispersed during gas reservoir adjustment. Gas-water cobedding is dominant in channel near fault. The local distribution characteristics of gas and water are controlled by the heterogeneity and local structure in the channel. The lithologic (physical) sealing developed in the channel can prevent the migration and loss of natural gas to the high fault layer, and make the gas and water distribution in the sausage type, while the gas layer is developed in the lower part of the structure. The distribution pattern of gas and water in the channel without lithologic sealing is "upper gas and water", the high part of local structure is gas layer, and the lower part of structure is water layer or gas and water layer.