A semi-analytic (p/z) rate-time relation for the analysis and prediction of gas well performance
A semi-analytic (p/z) rate-time relation for the analysis and prediction of gas well performance
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DOI：
10.2118/66280-pa
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发表时间：
2000-12-01
影响因子：
2.1
通讯作者：
Blasingame, TA
中科院分区：
文献类型：
--
作者：
Ansah, J;Knowles, RS;Blasingame, TA
在本文中，我们提出了储层枯竭期间边界主导气流解决方案的严格理论发展。这些解是通过将稳定流方程与气体物质平衡方程直接耦合而导出的。由于气体流量方程的高度非线性性质，多年来一直使用伪压力和伪时间函数来分析生产率和累积产量数据。虽然伪压力和伪时间函数确实提供了气体流量方程的严格线性化，但这些变换不提供直接解。此外，伪时间函数需要平均油藏压力历史记录，而这在大多数情况下根本不可用。我们的方法使用函数模型将粘度压缩率乘积表示为油藏压力/z 因子 (p/z) 剖面的函数。这些模型为边界主导流动期间的气流建模提供了近似但直接的解决方案。为了方便起见，解以无量纲变量的形式呈现，并表示为类型曲线图。这项工作的其他成果是 p/z 和 G(p)(t) 的显式关系。这些解决方案可以轻松适应现场应用，例如预测速率或累积产量。我们还使用数值模拟结果验证新的流量和压力解决方案，并使用现场示例演示这些解决方案的应用。
In this paper we present a rigorous theoretical development of solutions for boundary-dominated gas flow during reservoir depletion. These solutions were derived by directly coupling the stabilized how equation with the gas material balance equation. Due to the highly nonlinear nature of the gas flow equation, pseudopressure and pseudotime functions have been used over the years for the analysis of production rate and cumulative production data. While the pseudopressure and pseudotime functions do provide a rigorous linearization of the gas flow equation, these transformations do not provide direct solutions. In addition, the pseudotime function requires the average reservoir pressure history, which in most cases is simply not available.Our approach uses functional models to represent the viscosity-compressibility product as a function of the reservoir pressure/z-factor (p/z) profile. These models provide approximate, but direct, solutions for modeling gas flow during the boundary-dominated flow period. For convenience, the solutions are presented in terms of dimensionless variables and expressed as type curve plots. Other products of this work are explicit relations for p/z and G(p)(t). These solutions can be easily adapted for field applications such as the prediction of rate or cumulative production.We also provide verification of our new flow rate and pressure solutions using the results of numerical simulation and we demonstrate the application of these solutions using a field example.