Failure Analysis on Friction and Wear of Tool Joints

Abstract

Due to complex working conditions, such as deep wells, ultra-deep wells and extended reached horizontal wells, etc, the failures of friction and wear on tool joints often occur, which become one of the main failure models of tool joints. In this paper, some failure cases of the tool joint, including longitudinal crack, axial wash-out, necking deformation, and fracture were analyzed, and their macro profiles, micro characteristics and microstructure transformation were investigated. The results showed that since the material performances of tool joints met the requirements of product standard, the cracks, deformation and even strength degradation of tool joints can be caused by the heat generated by friction and wear between tool joint and the well wall, meanwhile, the heat didn't drain away in time. As a result, effective method to reduce friction heat generation, including improving quality of wellbore trajectory, reducing contact pressure, enhancing the stability of wellbore and so on, should be suggested in the field