考虑酸蚀蚓孔区影响的酸压油井产能方程

酸压过程中形成的蚓孔区将对酸压井产能产生影响。针对酸压后形成蚓孔区，根据压后流体渗流规律变化，建立了酸压井的物理渗流模型，推导建立了启动压力梯度和应力敏感共同影响下低渗油藏有限导流垂直酸压裂缝井产能预测模型，通过实例分析各因素对产能特征的影响。研究结果表明：油井产量随启动压力梯度增大而呈近似线性下降趋势；基于Terzaghi有效应力的应力敏感对油井产量的影响作用显著，油井产量下降幅度随压差增大而增大；油井产量随裂缝半长增加而增加，但增加幅度随之减小，而在一定裂缝长度下，裂缝导流能力存在一个最佳值；蚓孔区系统中的蚓孔长度和蚓孔区渗透率对油井产量的影响非常小，可忽略不计。

Productivity equation of acid fracturing oil well considering the effect of acid wormhole zone

The wormhole zone formed during acid fracturing can affect productivity of acid fracturing well. In view of the wormhole zone, based on change of fluid seepage law after fracturing, a physical seepage model for acid fracturing wells was established. And a productivity prediction model for vertical acid fracturing wells with finite conductivity in low - per- meability reservoirs was set up which is affected by start - up pressure gradient and stress sensitivity. From case analysis, it was studied on effect of various factors on productivity features. Results indicate that oil well productivity decreases with the increase of the start - up pressure gradient in a linear relationship ; the stress sensitivity based on the Terzaghi＇ s effec- tive stress significantly affect the oil well productivity, and decreasing rang of the oil well productivity increases with the in- crease of the production differential pressure;the oil well productivity increases with crack length increase, increasing range of the oil well productivity after certain value decreases, and there is an optimum fracture conductivity under a certain crack length;wormhole length and permeability of acid wormhole zone have very little effect on the oil well productivity.