广义管流-渗流耦合试井分析模型

A well test analysis model of generalized tube flow and seepage coupling

利用“广义流度”实现了管流和渗流模型在形式上的统一、实现了常用线性和非线性流动规律在形式上的统一,使得油气藏在不同区域或不同尺度上能够使用相同形式的运动方程构建统一的控制方程。定义了不同流动条件的广义流度,并由此建立了广义管流-渗流耦合的基本流动控制方程,构建了管道形复合储集体模型和部分打开圆柱形储集体模型这两种典型管流-渗流耦合的试井分析示例模型。管道形复合储集体模型压力降落双对数图可呈现两组线性流特征。部分打开圆柱形储集体模型压力降落双对数图可出现球形流和线性流特征,亦可出现球形流和径向流特征。两个示例模型的压力恢复导数曲线在前期与各自压力降落导数曲线基本重合,在后期均呈下坠特征,且生产时间越短下坠特征出现的时间越早。通过3个应用实例分析验证了模型的实用性和可靠性。图15表4参36。

"Generalized mobility"is used to realize the unification of tube flow and seepage in form and the unification of commonly used linear and nonlinear flow laws in form,which makes it possible to use the same form of motion equations to construct unified governing equations for reservoirs of different scales in different regions.Firstly,by defining the generalized mobility under different flow conditions,the basic equation governing fluid flow in reservoir coupling generalized tube flow and seepage is established.Secondly,two typical well test analysis models for coupling tube flow and seepage flow are given,namely,pipe shaped composite reservoir model and partially open cylindrical reservoir model.The log-log pressure draw-down type-curve of composite pipe shaped reservoir model can show characteristics of two sets of linear flow.The log-log pressure drawdown plot of partially opened cylindrical reservoir model can show the characteristics of spherical flow and linear flow,as well as spherical flow and radial flow.The pressure build-up derivative curves of the two models basically coincide with their respective pressure drawdown derivative curves in the early stage,pulling down features in the late stage,and the shorter the production time is,the earlier the pulling down feature appears.Finally,the practicability and reliability of the models presented in this paper are verified by three application examples.