水驱气藏动态储量及水侵量计算新方法

A NOVEL METHOD OF CALCULATING WATER-FLOODED GAS IN PLACE AND WATER INFLUX OF WATER DRIVE GAS RESERVOIRS

对于水驱气藏 ,特别是比较活跃的水驱气藏 ,水侵主要维持地层压力 ,并将产量维持在初始产量 ,直到水锥突破 ,其结果直接影响到气藏的采收率 ,因此如何准确计算水驱气藏储量和水侵量大小 ,从而进行动态预测显得非常重要。通过对物质平衡方程的分析 ,提出了利用地层压力及采出量等生产数据建立目标函数 ,利用最小二乘法进行自动拟合 ,直接计算水驱气藏动态地质储量及水侵量的新方法 ,同时该方法还可以确定水驱强度指数的大小。通过实例分析对比验证说明该方法计算结果准确、可靠 ,计算简单。

In water drive gas reservoirs, especially large water influx gas reservoirs, the water influx helps to maintain the reservoir pressure, and thus maintain gas productivity at initial productivity, at least until water breakthrough. As a result, the process directly affects the recovery. Therefor, it is of great importance to obtain accurate data of dynamic gas in place and water influx of the gas reservoir so as to make correct performance forecast. In this paper, a novel method is proposed. In the method the measured formation pressure and production data are used to build an objective function, and least square best-fitting is performed to obtain automatic matching, and thus the dynamic gas in place and water influx of the gas reservoir can be calculated directly. Comparative analyses of the results from this and other methods indicate that the proposed method is simpler and easier to use as well as accurate and reliable.