摩阻判断井眼情况的误差探讨

Error of Friction in Judging Wellbore Conditions

目前在现场,通常使用摩阻值或观察大钩载荷曲线是否有突变点,判断井下是否正常,但是摩阻取值和突变量没有定量评价标准。计算表明,井况正常时,下井钻具增加,摩阻增加;井斜增大,导致摩阻增加;更换钻具组合,大钩载荷曲线会发生突变,由此判断井下情况,会导致误差。本文提出使用摩擦系数客观定量评价井下情况,该方法可以消除钻具组合、井斜方位、井深、密度等参数变化的影响。

At present,the friction value or observation of the hook load curve is commonly used to determine whether the downhole is normal or not in the field.However,there is no quantitative evaluation standard for the friction value and the amount of mutation.Calculations show that when the well condition is normal,the drilling tool downhole increases and the friction also increases accordingly.The increase of well deviation can also cause the rise of friction.If the drilling tool assembly is replaced,the hook load curve has abrupt changes,which leads to errors in determining the downhole conditions.This paper proposes to use the friction coefficient to objectively and quantitatively evaluate the downhole conditions.This method can eliminate the influence of changes in parameters such as drilling tool assembly,well deviation azimuth, well depth, density and so on.