有水气藏开发早期动态储量计算方法研究

某地区须家河组有水气藏开发早期气水关系复杂,气井普遍产水,动态储量一直难以确定。根据低渗有水气藏生产动态及渗流特征,分析应用弹性二相法、压降法不能计算其动态储量。气井产水使气藏供气能力不足,气井生产制度不合理,造成用弹性二相法计算的动态储量偏低;产水气井和水淹井测得地层压力值偏低,导致压降法计算的动态储量必然误差较大。针对两种方法的缺点,建立了更适合产水特征的物质平衡方程,提出了计算有水气藏动态储量新方法——产量不稳定分析法,在计算过程中避免了"假拟稳态"的出现和实时测量井底流压的困难。通过实例分析研究表明,该方法计算简单、实用、准确,为气井的合理配产提供依据,对有水气藏的开发具有重要意义。

Research on Calculating Dynamic Reserve in the Early Stage of Water-drivenGas Reservoir Development

Xujiahe gas reservoir is characterized by complex relationship between gas and water , and gas well produced water generally, so calculating dynamic reserve gets difficult. From analysis of the production performance and percolating characteristics of low permeability water-driven gas reservoir, the elastic 2-phase method curves and pressure drawdown curves were not suitable for calculating dynamic gas reservoir. Water in gas well cause insufficient gas supply and low formation pressure, and create the dynamic reserve calculated being on the low side. Aiming to the problem of the dynamic reserves being hard to verify for the water-driven gas reservoirs with low permeability, the material balance equation is established for water-driven gas reservoirs. A new method to calculate the dynamic reserves for the water-driven gas reservoirs with low permeability is proposed. Using the method, the dynamic reserves can be verified respectively for the water-driven gas reservoirs with low permeability. With real cases, it is demonstrated the method is simple and practical, and has important significance for the development of the water-driven gas reservoirs with low permeability.