考虑垂向裂缝发育的火山岩气藏部分打开井试井分析方法

针对准噶尔盆地克拉美丽火山岩气藏物性差、非均质性强、裂缝类型以垂向的斜交缝和高角度缝为主等因素导致压力动态变化难以准确描述等问题，建立了一种考虑垂向裂缝发育的部分打开井模型，运用点源法、分离变量法和拉普拉斯变换法等方法，求解得到拉普拉斯空间下的解，通过Stehfest数值反演法得到实空间的数值解，绘制典型曲线图版，典型曲线分为6个主要流动段：井储段、过渡段、球形流段、早期径向流段、不稳定窜流段和晚期径向流段。将研究成果应用于克拉美丽气田滴西18区块的某井，对该井的3次试井测试进行了分析和解释，结果表明：该井呈现部分打开特征，垂向渗透率较大，随着生产进行，打开程度逐渐减小，水平渗透率变化较小且不稳定窜流段无明显变化，与生产资料基本一致。该模型不仅可以用于垂向裂缝发育的部分打开井的压力动态变化研究，还可以进行实测试井资料的试井分析和解释，研究结果可为火山岩气藏有效开发提供一定的理论依据。

Well test analytical model for a partial opening vertical well in enriched vertical fracture tight gas volcanic reservoir

Aiming at the challenges of the difficulties in describing the dynamic changes of pressure caused by the complex reservoir characteristics ，which are poor property， strong heterogeneity， high angle and partial vertical fracture development， etc. in Kelameili tight gas volcanic reservoir. A partial opening vertical well test analytical model based on vertical fracture is established. The solution of bottom-hole pressure is obtained by using point source method， separate-variable method， etc. in Laplace space， and by using Stehfest numerical inversion method in real space. A type curve template is made， which includes 6 main flow regimes： wellbore storage， transition， spherical flow， early radial flow， dual-porosity transient flow and radial flow. This research result is applied to a well in Dixi 18 area of Kelameili Gasfield， the well test curves are analyzed and interpreted， and the results show that the well has the feature of partial opening， and vertical permeability is large， and the wellbore-opening degrees are gradually decreasing， the horizontal permeability changes little and the dual-porosity transient flows have no significant changes with the progress of production， which are basically consistent with the production data. The research results provide a research idea for the construction of well test analytical model of tight gas volcanic reservoir， and the partial opening vertical well model can not only analyze the dynamic changes of pressure of tight gas volcanic reservoir， but also be used for well test analysis of field examples， and provide a theoretical basis for the effective development of tight gas volcanic reservoir.