Mechanical Analysis of a Multi-Test String in High-Temperature and High-Pressure Deep Wells

The mechanical behavior of the test string in deep wells is generally relatively complex as a result of the high temperature and high pressure, severe dogleg and buckling effects, which in some circumstances can even lead to string failure. Traditional computational methods for the analysis of these behaviors are often inaccurate. For this reason, here a more accurate mechanical model of the test string is introduced by considering variables such as temperature, pressure, wellbore trajectory, and buckling, as well as combining them with the deformation and string constraint conditions brought in by changes in temperature and pressure during the tripping, setting, and test operations. The model is validated by applying it to a specific high-pressure gas well (located in Northeast Sichuan).