目前对活跃边水气藏稳产期末的采出程度预测没有特别有效的手段,经常出现产量在没有任何征兆的情况下发生快速递减。以雅克拉水驱气藏储层长岩心物理模型为基础,通过水驱气实验模拟水侵过程气水两相渗流特征;以水驱物质平衡方程为理论方法,引入水侵系数概念描述气藏水侵特征。由于注入水的含烃孔隙体积与水侵系数概念一致,通过水驱实验模拟活跃边水气藏水侵对气藏的影响是可行的。实验结果表明,当注入水达到0.3 ~ 0.45倍HPV（含烃孔隙体积）时,水驱前缘突破,天然气产能从稳产期进入快速递减期。生产历史表明,中下气层水侵系数达到0.33 ~ 0.36时,天然气产能快速递减,实验和生产实际基本吻合。通过对上气层开展水侵系数计算,2019年8月至2020年2月水侵系数达到0.33 ~ 0.36时,进入稳产末期,和数值模拟结果基本一致,需及时对高风险井进行调整。

At present, there is no particularly effective method to predict the degree of production at the end of the stable production period of gas reservoirs with active edge water. The production often declines rapidly without warning. Based on the physical model of long core of gas reservoirs by water flooding in Yakela area, the characteristics of gas-water two-phase seepage during water invasion are simulated by the experiment of gas recovery by water flooding. Taking the material balance equation of water flooding as the theoretical method, the concept of water invasion coefficient is introduced to describe the water invasion characteristics of gas reservoirs. As the hydrocarbon pore volume（HPV） of the injected water is consistent with the concept of water invasion coefficient, it is feasible to simulate the effect of water invasion on gas reservoir by water flooding experiments. The experimental results show that when the injected water reached 0.3 ~ 0.45 times of HPV, the waterflood front breaks through, and the gas production enters the rapid decline period from the stable production period. The production history shows that when the water invasion coefficients of the middle-lower gas reservoir reach 0.33 ~ 0.36, the gas production decreases rapidly, and the experiment is basically consistent with the production practice. By calculating the water invasion coefficient of upper gas reservoir, when the water invasion coefficients reach 0.33 ~ 0.36 from August 2019 to February 2020, the end of stable production period will come. It is basically consistent with the results of numerical simulation and necessary to adjust the high risk wells in time.