考虑天然气高压物性变化的气藏平均压力计算方法

地层平均压力是气藏分析的重要参数,虽然目前计算方法较多,但大多需要通过关井来实现。针对定容气驱气藏,在考虑天然气高压物性随压力变化的基础上,结合物质平衡原理及气藏渗流机理,建立了地层压力与生产数据的关系等式,提出了在不关井的前提下,利用生产数据计算地层平均压力的方法。同时依据该方法,给出了地层平均压力的计算图版,进一步提高了该方法的实用性。通过验证,利用该方法确定的地层平均压力误差在2%以内,具有较高的精度。

The Calculation Method of Average Reservoir Pressure Considering Natural Gas High Pressure Physical Properties Changing

Average reservoir pressure is one of the important parameters of gas field analysis, although the calculation methods are various, most of which need gas well shut-in. In this paper, we establish a method to calculate average reservoir pressure by using production data without shut-in, which is on the basis of material balance principle and the gas seepage mechanism. In this method, natural gas high pressure physical properties changing with pressure is also considered. Meanwhile, average formation pressure calculation chart is given according to flowing material balance, which will further improve the practicability of this method. Through validation by reservoir numerical simulation, the error of average reservoir pressure determined by this new method is within 2%, which make a high precision.