提高边水气藏采收率的方法研究

气藏开发实践表明，边水气藏的采收率要比定容气藏低得多。如何采取有效的方法提高边水气藏的采收率一直是气藏开发领域的一大难点。为此，从目前边水气藏的采收率普遍较低的现状分析出发，通过对边水气藏气、水两相渗流特征及影响水驱气藏采收率机理的分析发现，气藏的废弃压力和水侵波及系数是控制气藏一次采收率的主要因素。为提高边水驱气藏的采收率，目前传统的做法是控制气藏开采速度、保持气藏能量、尽可能地延长气藏的无水采气期和控制边水的入侵速度，这种开采方式最终造成边水气藏水淹时的废弃压力很高，而采收率较低的局面。由此建立了加快边水气藏开采速度、降低气藏废弃压力、增大水侵体积系数可以有效地提高边水气藏采收率的观点，文章从理论上论证了该思路的可行性，并以实际边水气藏为例进行了计算，计算结果说明了本思路的正确性。

THE METHOD OF IMPROVING RECOVERY EFFICIENCY OF EDGE WATER DRIVE GAS RESERVOIRS

Gas reservoir development indicates that edge water drive gas reservoir is much lower in recovery efficiency compared to fixed volume gas reservoir. It has remained a challenge of gas development how to enhance edge water drive gas reservoir recovery efficiency. This paper analyzes edge water drive gas reservoir gas-water two phase flow characteristics and mechanism affecting recovery efficiency, then points out that the main factors which affects its' recovery efficiency are abandonment pressure and water invasion index. To increase recovery efficiency, traditional methods have been used to control the development rate and conserving reservoir energy in order to prolong water-free gas production period and control edge water cut rate, which eventually brings about high abandonment pressure and low recovery efficiency. Therefore, it is presented a new point of view, that is, high recovery efficiency for edge water drive gas reservoirs can be achieved by speeding up development, reducing low abandonment pressure, and increasing big water invasion index. It is demonstrated that proposed viewpoint is feasible in theory and exemplifies with real edge water gas reservoir calculation, and the correctness of the approach can be indicated by the outcomes.