关键词: 水平气井, 试井分析, 数学模型, 典型曲线, 特征值方法

Abstract: The seepage flow mechanism in horizontal gas well is complicated, and the analysis of test data from the transient well is also difficult. A mathematical model was established for well test analysis of horizontal gas well with boundless horizontal extension. The typical curves of well test analysis were plotted by Stehfest inversion algorithm to distinguish different flow stages and obtain reservoir parameters. There are four obvious stages on the pressure derivative curve, including pure well bore storage stage, early vertical radial flow stage, early linear flow stage and late horizontal radial flow stage. The characteristic lines manifested by derivative curve with four stages were used to derive the formulas of horizontal permeability, vertical permeability, skin factor and initial reservoir pressure. The characteristic value method for the well test analysis of horizontal gas well was proposed and verified by an exact case.

Key words: horizontal gas well, well test analysis, mathematical model, typical curve, characteristic value method