确定产水气井流入动态关系的新方法

当地层为单相气体渗流时，气井二项式产能方程系数A、B中的渗透率为地层渗透率；当地层为气水两相流动时，则系数A、B中的渗透率为气相渗透率。为确定产水气井的产能方程，基于气体地下稳态渗流理论建立的产能方程，在没有产能试井资料的情况下，提出了利用产水气井生产动态参数确定产水气井流入动态关系的新方法。该新方法主要包括：首先根据垂直管气水两相流压力计算方法，结合产水气井动态参数，确定对应的井底流压；进而利用初期不产水时的不稳定试井解释成果，结合目前的生产动态资料及压力资料，确定对应的气相渗透率；最后，根据确定的气相渗透率，结合产水气井气相二项式产能方程，确定产水气井流入动态关系。利用该新方法对产水气井进行了实例计算，分别获得了不产水及产水情况下的二项式产能方程。计算结果表明，气井产水使得二项式产能方程系数A、B变大，气井无阻流量大大降低。

A new method of determining the inflow performance relationship in water producing gas wells

When it comes to a single phase flow in the strata, the permeability in binomial coefficients A and B of binomial deliverability equation for a gas well stands for formation permeability, but when it comes to a gas water two phase flow, it turns to be gas phase permeability. Based on the deliverability equation established upon the steady seepage theory of gas underground, and in the absence of deliverability test data for a gas well, this paper presented a new method of determining inflow performance relationship of water producing gas wells by using dynamic production parameters of water producing wells. This new method mainly includes the following contents: First, the corresponding bottomhole flowing pressure is determined according to the gas & water flowing pressure calculation method of a vertical pipe and dynamic parameters of a water producing gas well. Second, the corresponding gas permeability is determined according to transient well test results while non water producing at the preliminary stage in combination with dynamic production parameters and pressure data at the current stage. Finally, the inflow performance relationship of a water producing gas well is determined according to the calculated gas permeability and binomial deliverability equation for a water producing gas well. This method was put into practice for the calculation of a water producing well, and the binomial deliverability equations were obtained for a gas well with and without water production respectively. The calculation results show that when there is water produced in a gas well, the coefficients A and B in the binomial deliverability equation for the well are made greater and its open flow capacity is remarkably reduced. This study provides a new idea for determining the deliverability equation of a water producing gas well.