气藏递减期生产动态预测定量关系模型

Production performance prediction quantitative relationship model of gas reservoir production decline period

稳产期结束后,气藏开发进入产量递减期。为快速、准确预测气藏生产动态规律,基于气藏采气速度与稳产期定量关系研究成果,结合定容气藏物质平衡方程和气井二项式产能方程,应用气藏工程原理,建立正常压力气藏递减期生产动态预测定量关系模型,得出了气藏递减期采气速度与生产时间定量关系式。以某气井为计算实例,将文中方法与数值模拟方法对比。计算结果表明:该模型能准确预测任意稳产期采气速度下产量递减期的生产动态。同时,从该模型中能得出部分影响气藏产量递减快慢的因素。

After finishing the production plateau duration, development of gas reservoirs enter into production decline period. For predicting the production performance of single reservoir, the material balance method and numerical simulation method have been widely adopted by previous researchers. It is time consuming and less efficient, if numerical simulation method was used to optimize development scheme. In order to predict the production performance precisely and rapidly, and evaluate economic benefit and design reasonable development plan of gas field. On the basis of research result of quantitative relationship between gas off-take and plateau duration of natural gas reservoir, and combining material balance equation of constant volume gas reservoir with gas well binomial productivity equation, a quantitative relationship model between gas offtake （the gas recovery per year）during production decline period and production time has been derived in this paper. Considering heterogeneity of real gas reservoir, reservoir numerical simulation method has been applied to determine the mod- el parameters. Taking a certain well as calculation example, comparison between the pro-posed method and reservoir simulation has been made. The calculation result shows that this model could predict production performance of decline period exactly. Meanwhile, part of the influence factors that affect the production decline speed of gas reservoir could be obtained.