裂缝型产水气藏水侵机理研究

在裂缝-孔隙型有水气藏开采过程中，边水或底水容易沿裂缝通道向生产井窜流，形成气水两相流，增加渗流阻力，封闭并分隔部分气区，降低井产量和气藏采收率，对采气危害很大。针对裂缝型产水气藏的储集层特征，建立了水驱气渗流的物理实验模型，通过实验，从微观机理上揭示了裂缝型气藏发生水侵时天然气主要以绕流封闭气、卡断封闭气和水锁封闭气的形式存在。气藏水侵在宏观上主要表现为低渗透岩块水侵、气藏水侵和关井复压“反向水侵”，其结果是水对气区进行封闭、封隔和水淹，堵塞部分气区的渗流通道，使可动气变成“死气”。结合气藏水侵机理研究了K6井裂缝系统的水侵规律，为该气藏开发调整提供了有效的依据。

Studies on Water Invasion Mechanism of Fractured-watered Gas Reservoir

During the development of fractured and watered gas reservoir,production wells can be easily accessed by the edge water or bottom water along the fracture channel,and gas-water flow is developed.This causes the increase of flow resistance,closure and separation of some gas area,hence,the decrease of well production and recovery,which has great harm to gas production.Based on the characteristics of the fractured and watered gas reservoir,a physical model of displacement of gas by water is established.By means of water invasion seepage modeling experiment,the microscopic mechanism of water invasion about the gas reservoir is found.When the gas reservoir is watered,gases are dominated by trapped gas,cut gas and water-locked gas.Water invasion of gas reservoir can be macroscopically classified into water invasion of rocks with low permeability,water invasion of gas reservoir and “reverse water invasion” of well shutdown.It makes the gas area separated and watered,and changes the mobile gas into “dead gas”.Combined with the mechanism of water invasion of gas reservoir,the water invasion rules of K6 gas well fracture system has been studied,which provided a sound basis for the development and adjustment of gas reservoirs.