油气藏型储气库产能计算新方法

A new method for production capacity calculation of gas storage in oil and gas reservoirs

气井产能研究不仅是气藏动态描述的核心,也是储气库注采气能力分析、注采方案编制的重要依据。目前常规二项式、指数及一点法产能方程是针对气藏开发建立的,对储气库周期性高速注采的适用性还没有相关研究。为此,针对油气藏型储气库产能计算方法开展相关研究,通过储气库气井地层压力、井底流压和注采气量的关系,建立了油气藏型储气库产能方程,并明确方程中各参数的物理意义,进而界定层流和紊流的阈值。不同于常规气藏产能方程,油气藏型储气库产能方程中的生产压力平方差与产量的平方比随着产量的增加而降低,呈無函数关系,在双对数坐标系中呈线性关系。建立的油气藏型储气库产能方程是对常规气藏产能方程的拓展,为储气库的注采气能力研究提供了理论依据。为验证新建立产能方程的适用性,分别应用二项式产能方程和新建立的产能方程对X储气库4口压力监测井的实测生产数据进行拟合对比,结果表明新建立的产能方程更符合油气藏型储气库产能变化规律。

The research on the production capacity of gas wells is not only the core of the performance description of gas reservoirs but also an important basis for the analysis of gas injection and production capacity and the preparation of injection and production schemes of gas storage.At present,the conventional binomial,exponential,and one-point productivity equations are established for gas reservoir development,and there is no relevant research on the adaptability of cyclic high-rate injection and production of gas storage.Therefore,this study investigated the productivity calculation methods for gas storage in oil and gas reservoirs.On the basis of the relationships between formation pressure,bottomhole flow pressure,and injection and production capacity in gas storage in oil and gas reservoirs,the productivity equation of gas wells in gas storage was established,and the physical significance of various parameters in the newly established productivity equation of gas wells was clarified to define the thresholds of laminar flow and turbulent flow.Different from the productivity equation of the conventional gas reservoirs,the newly established equation demonstrates that the ratio of the difference of squares of production pressure to the square of production decreases with the increase in production,which satisfies the power function relationship and shows a linear relationship in the double logarithmic coordinate system.The established productivity equation of gas storage in oil and gas reservoirs is an extension of the conventional productivity equation,which provides a theoretical basis for the study of gas injection and production capacity of gas storage.To verify the applicability of the equation proposed in this paper,we used the binomial productivity equation and the newly established equation to fit the measured production data of four pressure monitoring wells in X gas storage for comparison.The results show that the equation established in this paper is more in line with the productivity change laws of gas storage in oil and gas reservoirs.