确定钻井液侵入油层伤害的数值模拟计算方法

Numerical stimulating model for determining formation damage because of drilling fluid invasion

钻井液会侵入油气层并在近井眼周围形成伤害区,其伤害深度和程度可应用钻井液侵入模型来计算。该方法在建立了预测侵入近井眼地带钻井液的浓度随径向距离变化的数学模型的基础上,通过数值积分确定钻井液侵入深度和伤害油层程度,计算中不需要复杂的钻井液滤失的岩心流动实验,只需钻井液性能参数和地层孔渗资料,应用钻井现场资料就可以较准确地确定钻井液侵入深度和伤害程度,方法简单,应用方便。通过试井方法证明该方法是正确的。

The invasion of drilling fluid into formation may cause severe damage around the near borehole area, and by applying the numerical stimulating model, its damaging depth and degree may be worked out. Basing on the mathematical model of predicating the drilling fluid concentration near the wellbore area according to the radical distance changes, and by the way of numerical integration, drilling fluid invasion depth and formation damage degree can then be determined. Core flow test is not required, and only drilling fluid performance parameters and formation porosity and permeability data is needed, and these can be obtained from rig site data. This method is simple and easy for use, and it is proved reliable through well testing.