一种确定水驱气藏动态储量及水体能量的新方法

A new method for determining dynamic reserves and water energy in water drive gas reservoir

动态储量及水体能量作为含水气藏开发过程中的2个关键参数,目前的研究方法及求解方式均基于物质平衡原理,且参数获取及求解过程较为繁琐。以水驱气藏物质平衡原理为基础,建立水驱气藏物质平衡数学理论模型,并引入新的水体能量参数,结合气水两相相渗曲线,在动态储量和水体强度为未知数的条件下,得到累计产气量与累计产水量的关系式,建立了求解动态储量及水体能量参数的最优化模型。实例分析表明:利用本文模型能够较为快速地同时计算出动态储量与水体能量参数;与4种经典方法对比,绝对误差与相对误差均较小,且避免了地层压力测试及水侵量计算过程。敏感性分析表明,随着水体能量的逐渐增大,气藏动态储量逐渐减小,表明了水封气对动态储量的影响较为明显。研究成果为水驱气藏开发研究提供了理论依据。

Dynamic reserves and water energy are both important parameters during developing water drive gas reservoirs.The current method to calculate them are both from the foundation of principle of material balance,and the way to get the parameters and solution procedure are both complicated.Based on the principle of material balance equation in water drive gas reservoir,this paper deduces the material balance equation,defines the parameter of water energy,and combines with gas-water relative permeability curve to get the relation between cumulative gas production and cumulative water production including the unknowns of dynamic reserves and water energy parameters,and build an optimization model to solve the dynamic reserves and water energy parameters.Case study shows that dynamic reserves and water energy parameters can be quickly calculated by the new model,and the results calculated by the new method in this paper have less absolute and relative errors than that calculated by 4 classical methods,and using the new model does not need pressure test and water influx calculation.Sensitivity analysis shows that dynamic reserves decreases with water energy increase,indicating that water-trapped gas has much influence on dynamic reserves.The research results provide theoretical basis for the development of water drive gas reservoirs.