温度和机械载荷联合作用下油田超深井中硬质涂层膨胀锥与套管的屈服挤毁压强及试验验证

Yield collapse pressure between expansion cone with hard coating and casing in ultra deep well in oilfield under temperature load and mechanical load and experimental confirmation

在充分考虑温度载荷、机械载荷、硬质涂层膨胀锥硬度、套管硬度对膨胀锥与套管之间屈服挤毁压强影响的基础上,根据分形理论和接触力学推导出膨胀锥与套管之间屈服挤毁压强的计算公式.数值分析表明:膨胀锥与套管之间的屈服挤毁压强随最终温度、分形粗糙度、线膨胀系数、硬质涂层膨胀锥布氏硬度、中间主应力系数、套管壁厚的增大而增大;当分形维数从1增大时,膨胀锥与套管之间的屈服挤毁压强随分形维数的增大而减小;当分形维数增大到接近于2时,膨胀锥与套管之间的屈服挤毁压强随分形维数的增大而增大;随拉压强度比的增大,膨胀锥与套管之间的屈服挤毁压强减小.屈服挤毁压强的计算值与试验测试值之间的相对误差为-8.9253%^-0.9901%.

With sufficient consideration about temperature load,mechanical load,expansion cone hardness with hard coating and casing hardness,the computational equation was deduced to calculate yield collapse pressure between expansion cone and casing by fractal theory and contact mechanics.Digital analyses show that yield collapse pressure between expansion cone and casing adds with the increasing final temperature,fractal roughness,linear expansion coefficient,Brinell hardness of expansion cone with hard coating,intermediate principal stress coefficient and casing wall thickness.Yield collapse pressure between expansion cone and casing decreases with the increase in fractal dimension from 1.Yield collapse pressure between expansion cone and casing enhances with the augment in fractal dimension close to 2.Yield collapse pressure between expansion cone and casing reduces due to the increase in tensileto-compressive strength ratio.Relative errors between calculable values for yield collapse pressure and experimental measurement ones lie within the range from-8.9253%to-0.9901%.