考虑流动边界影响的气井非达西效应评价

基于高产气井向井流的流动规律，从描述非达西流动的Forchheimer二次方程出发，建立了考虑非达西流动边界影响的产能方程，给出了相应的非达西流动系数与表皮系数的计算方法，从而完善了由稳定试井评价气井非达西流动效应的方法。流动边界对非达西流动系数影响的分析结果表明，当非达西流动半径与井筒半径可比时，忽略该流动边界影响，非达西流动系数明显偏大，会导致高估非达西流动效应。实例计算结果证实了非达西流动边界对非达西流动效应评价有显著影响。

Evaluation of non-Darcy flow effect in gas well considering influence of flow boundary

According to the flow law of gas through reservoir with non Darey flow around wellbore and Darcy flow far from wellbore of gas well with high production, the deliverability equation was found in consideration of the influence of flow boundary and derived from the Forchheimer formula for non-Darcy flow. The calculation method of non-Darcy flow coefficient and the skin factor was given, and the evaluation method of non-Darcy flow effect based on the steady state well testing was improved. The effects of flow boundary on non Darcy flow coefficient were analyzed. The result shows that the non-Darcy flow effect is overrated because higher non Darcy flow coefficient without considering the influence of flow boundary is given when the radius of non-Darcy flow and the radius of wellbore are comparable. The flow boundary of non-Darcy flow has obvious influence on the evaluation of non-Darcy flow effect.