| 摘要 |
A string of well tubulars, such as a well casing or a drill string, is prior to installation of the string in a borehole magnetized along at least part of the length thereof by creating a magnetic field having flux lines which pass in a substantially longitudinal direction through an elongate section of the string, thereby magnetizing said section such that it has opposed magnetic poles having a polestrength of more than 3000 mu Wb. |
