利用修正等时试井确定凝析气井拟压力产能方程

DETERMINING PSEUDOPRESSURE DELIVERABILITY EQUATION OF GAS CONDENSATE WELL WITH MODIFIED ISOCHRONAL TEST

在凝析气井产能评价中,利用拟压力两相渗流数学模型计算产能,能有效反映凝析气液两相渗流特征,比常规单相压力平方法计算的产能更准确,但模型涉及物性参数较多,参数间具有动态变化关系,因此,计算较为繁琐,方程系数不易确定。结合不稳定产能测试,引入修正等时试井方法及积分元素法对产能方程进行求解分析。首先基于考虑相变的凝析气井拟压力方法,建立气液两相渗流数学模型;然后结合实验室静态资料,运用积分元素法对模型中拟压力函数进行求解;再根据修正等时试井原理,利用不同工作制度下的动态测试产能点计算产能方程系数,从而确定凝析气井两相渗流拟压力产能方程。现场实例表明,与凝析气井常规单相渗流模型相比,运用该方法所得凝析气井产能偏小,这反映了凝析液析出对气井产能的影响,其结果更符合实际生产情况。因此为快速有效地确定凝析气井产能提供了一种实用方法。

For evaluating deliverability of gas condensate wells,the deliverability was calculated by pseudopressure two phases flowing model that reflected characteristic of gas-liquid two phases flowing better,but there are many parameters that have dynamic relationship each other in the model,and it is difficult for calculation.With transient deliverability testing,the deliverability was analyzed by method of modified isochronal test and element of integration.Firstly based on method of pseudopressure considering phase change,deliverability model of gas-liquid two phases flowing was established,and in process of the resolution,with experimental data,pseudopressure function of the model was analyzed by the way of element of integration.And then according to modified isochronal test rule,the deliverability equation factors were calculated with testing production data at condition of different working system,and deliverability equation of gas condensate well should be obtained.The absolute open flow was gained by drawing inflow performance curve based on deliverability equation.The gas field example indicated,in comparison with the conventional single phase flowing model,the result of evaluating deliverability by the method was smaller that reflects the influence of condensed liquid on deliverability,and it was more coincided with actual production.So,it provided a utility way for evaluating deliverability of gas condensate wells quickly and effectively.