各向异性油藏水平井变流量压力动态响应计算方法

A calculation method for the pressure behavior response of horizontal well in anisotropic reservoirs at variable flow rate

为了解决海上油田现场缺少高精密压力监测数据的问题,利用水平井历史生产数据和不稳定试井分析方法进行各向异性油藏水平井的评价和预测。基于水平井的三维源函数和Newman乘积原理建立变流量各向异性油藏水平井压力动态响应关系,并将该关系式离散化转换为可实际应用的卷积和矩阵形式的水平井变流量压力响应试井模型,最后应用最优化算法求解模型最优解。该模型可用于评价水平井油藏生产动态特性,同时也确定了计算过程中构成水平井点源函数中级数项数目,应用最优化方法求解确定的模型参数也可用于生产动态预测。实际现场应用结果表明,变流量水平井压力动态响应模型的计算结果符合实际生产动态,相对误差平均3.1%,对评价水平井油藏特性、预测水平井开发生产具有现实指导意义。

Offshore oilfields are lack of high-precision pressure monitoring data. In order to solve this problem by applying the historical production data and transient well test method to evaluate and predict horizontal wells in anisotropic reservoirs, the pressure behavior response relation of horizontal well in anisotropic reservoirs at variable flow rate was established based on the three dimension point source function of horizontal well and the Newman product principle. Then, this relation was discretely transformed into the pressure response well test model of horizontal well at variable flow rate in the form of convolution and matrix which is practically applicable. Finally, the solution was calculated by means of the optimization algorithm. It is indicated that this model can be used to evaluate the production performance of horizontal wells and determine the number of the series terms constituting the point source function of horizontal well in the process of calculation, and the model parameters determined by the optimization algorithm can be also used for production performance prediction. Field application results show that the calculation results of the pressure behavior response model of horizontal well at variable flow rate is accordant with the actual production performance, and the average relative error is 3.1%. The research results are practically of instructive significance to evaluate the oil reservoir characteristics of horizontal wells and predict the development and production of horizontal wells.