考虑温度影响的摩阻扭矩计算模型及应用

A torque and drag calculation model with consideration of temperature effect and its application

管柱在井下受热,产生的热应力会改变管柱轴向力,影响摩阻扭矩的计算。通过实验测量钻井液在不同温度下的润滑系数和泥饼黏滞系数,拟合出其随温度变化关系,结合热应力的作用,建立考虑温度影响的摩阻扭矩计算模型。实验结果表明,KCl聚合物润滑钻井液和油基钻井液的润滑系数和泥饼黏滞系数随温度升高而增大。应用该模型对涪陵页岩气焦石坝区块X井进行摩阻扭矩计算,得出考虑温度影响的计算模型顶驱扭矩误差为3. 7%,大钩载荷误差为4. 4%,计算精度较高。

When drill pipes are subjected to variable circulating temperatures in the wellbore,the thermal stress induced will change the axial forces on the pipes,which can affect the calculation of the torque and drag.In this study,the effects of temperature on the lubricity coefficient and cake frictional coefficient of drilling fluids were measured via indoor experiments,and a torque and drag prediction model was established considering the effect of temperature on the friction coefficient and axial force.The results show that both the lubricity coefficient and cake frictional coefficient of KCl polymer drilling fluids and oil based drilling fluids can increase with temperature.A case study for well drilling in Fuling Jiaoshiba region was conducted,and the results show that the errors of the top drive torque and hook load can be of 3.7%and 4.4%,respectively,when the effect of temperature is not considered.