低渗致密气藏压裂水平井产能预测新方法

A New Method of Predicting Gas Wells′Productivity of Fractured Horizontal Well of Low-permeability Tight Gas Reservoir

压裂水平井是有效开发低渗致密气藏和页岩气藏的主要手段,压裂水平井产能是决定非常规气藏开发成败的关键技术指标。但目前能够经济、快速地获得低渗致密气藏压裂水平井产能的方法很少。基于此,采用理想模型与数值模拟相结合的方式,得出了一种能快速评价低渗致密气藏压裂水平井产能的新方法。根据我国低渗透致密气藏的地质特点,建立了单井数值模拟模型。设计了8组16次正交试验,并对其进行了修正等时试井数值模拟。模拟结果表明,储层渗透率和储层有效厚度是影响气井产能的2个主要因素,并建立了不同裂缝条数的压裂水平井的二项式产能方程系数A和B与地层系数的经验关系。通过实例验证,该方法具有计算简单、适用性强、结果可靠的特点,能够节省大量时间和成本,适合现场快速评价应用。

Fractured horizontal well is an effective method to develop low-permeability tight gas reservoirs and shale gas reservoirs. And the productivity of fractured horizontal well is the key factor which can determine whether un- conventional gas reservoirs could be developed effectively. However, there are rare methods which can be used to calculate productivity rapidly,effectively and simply. Therefore, under such a circumstance,it is imperative that re- searchers should make out new effective measures to improve current condition. To solve this problem, based on numerical simulation and an ideal model, this paper established a new method which could predict fractured horizon- tal gas wells＇ productivity in low-permeability tight gas reservoirs rapidly, economically and efficiently. According to the geological characteristics of low-permeability tight gas reservoirs in China, single well＇s simulation model has been established. Then a 8 × 16 orthogonal vector was set up and the processes of revision isochronal well test were simulated. The simulation results show that effective permeability and thickness of the reservoir are the most im- portant two parameters among those which can influence the productivity of gas wells. At the same time, the results can be regressed to relationship equations between binomial deliverability equations＇ factors （A and B） and forma- tion capacity. The practical application shows that this method has convenient operation and reliable result, and is well-adopted, economical and time saving. Particularly, these productivity equations are suitable for field application.