Abstract: For the extended well, high angle drilling, horizontal drilling and deep well drilling, or in the well section of large dogleg severity, or the long open hole, casing wear often happens. As a result, the collapse resistance and the bursting pressure of the worn casing will decrease, which will affect the well
completion, well test, and oil well life, and sometimes gives rise to the abandonment of a well section or the whole well. Hence, the scholars at home and abroad have obtained some measures to abate the casing wear. In this paper, the principle of theses measures was studied, which will help the oil field to select or the researcher to study. Because of the good effect and
convenience of the hardbanding, it is a good method to use in the oil field.

Key words: casing wear, hardbanding, wear resistance connector