基于流动物质平衡原理计算气藏平均地层压力

Calculation of average reservoir pressure by using modified flowing material balance

平均地层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。文中针对定容气藏,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式,提出了在不关井的前提下,利用生产数据计算平均地层压力的方法。同时,依据该方法原理,给出了平均地层压力的计算图版,进一步提高了该方法的实用性。通过验证,利用该方法确定的平均地层压力误差在2%以内,具有较高的精度。

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 to obtain the data. 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, according to flowing material balance, average formation pressure calculation chart is given, which will further improves the practicability of this method. Through validation by reservoir numerical simulation, the error of average reservoir pressure calculated by this method is within 2%, which shows a high precision.