以缝洞型油藏单井缝洞单元注水压降试井过程中流体的流动过程及能量平衡状态为基础,建立注水压降试井过程中井底压力与关井时间的变化关系。研究表明,可以将碳酸盐岩缝洞型油藏注水压降试井过程中的压力降落分为三个部分:流体在近井地带克服"表皮效应"产生的压降;流体在裂缝系统中克服渗流阻力产生的压降;裂缝系统向溶洞系统补充能量产生的压降。在此基础上建立了一种估算储集体地层参数的方法,与传统解析试井方法对比,该方法基于物质平衡方程,从能量平衡的出发,对非均质性强的地层适应性更好。使用现场生产实践获得的实测数据对新模型进行验证,发现新模型与实测曲线拟合精度高,计算参数满足工程精度并且计算步骤简便。因此,该方法对于碳酸盐岩缝洞型油藏工程决策的制定有所帮助。
According to fluid flow process and energy balance of draw-down well test in fractured-vuggy units of fractured-vuggy reservoir, this paper establishes a change relation between bottom hole pressure and shut in time. The research shows that the pres- sure drawdown can be divided into three parts: the first one is that the pressure drawdown produced near wellbore area by overcom- ing "skin effect", the second one is that the pressure drawdown produced in fracture network by overcoming fihrational resistance, the third one is that the pressure drawdown produced between fracture network and vuggy system, accordingly, a method to estimate formation parameters is established. Compared with traditional analytical well test method, this method is based on material bal- ance equation, which has better adaptability for strong heterogeneity reservoir. Field data are used to show that the predictions from this approach are in agreement with the results calculated from field data and can be obtained very quickly. As a result, this method can provide references for making decision for carbonate fractured-vuggy reservoir.