凝析气藏产能方程异常分析

Abnormal productivity equation of condensate reservoir

根据低渗、高温、异常高压凝析气井的试采资料,用传统的气藏工程方法建立的产能方程可能出现负斜率曲线的异常现象,由于获得相对渗透率等相关资料困难,凝析气拟压力方法难以操作。根据工程应用的需要,从产能基本方程入手,通过计算分析油气两相分离过程、状态方程、油气两相相对渗透率积分,提出便于操作而且实用的建立凝析气产能二项式方程的两种方法:劈分气相拟压力方法和基于区域平均相对渗透率曲线的两相拟压力方法。应用这种方法分析塔里木盆地柯克亚气田KS101井试采资料,计算的气井产能与实际生产资料符合。

Productivity equation based on traditional reservoir engineering method sometimes leads to negative slope, which is meaningless for the testing data of condensate well with low permeability, high temperature and very high pressure. And the pseudo-condensate pressure method remains to be inapplicable because of the difficulty to acquire the relative permeability data. Based on engineering demand and basic productivity equations, two methods to derive the binomial productivity equations are put forward by analyzing the separation of oil and gas, the equation of state and the integral of relative permeabilities: split gas pseudo-pressure (SGPP) method and typical regional relative permeability pseudo-pressure ( TRRPPP ) method. These pseudo-pressures make the productivity equation very applicable for condensate reservoir. The methods are used to interpret the well testing data of the Well KS101 in Kekeya gas field, Tarim Basin. The results present a high consistency with the daily performance of the well.