Method for drilling deviated wellbores.

摘要

Directional drilling of a high-angle wellbore is carried out by the drilling of a vertical first portion (3) to a kick-off point (7) at which a high-angle, deviated second portion (9) is initiated. The wellbore is cased to at least below the kick-off point. A casing liner (31) is lowered through the wellbore so that it extends coextensively with the casing (13). The liner is spaced from the casing by a casing hanger (32) positioned above the kick-off point. The liner is sealed in the casing and prevented from rotating during drilling by a packer bore receptacle (35) positioned between the lower end of the liner and the casing. During the drilling of the deviated second portion of the wellbore, the casing liner protects the casing from wear due to the rotation of the drill string (17) as it lies on the lower side of the high-angle wellbore.