Method and apparatus for placing a cement lining in a borehole.

摘要

A cement lining is placed in a borehole using a cementing apparatus including a centralized stinger (6) which is suspended from a cement injection tubing (5). In use a cement slurry is introduced into the annular space (3) surrounding the tubing and stinger and after subsequently filling the interior of the tubing and stinger with mud the apparatus is pulled thereby leaving in the borehole a cement plug with an open or soft core. The centralization of the stinger ensures that after hardening of the cement a cement layer of a constant thickness is created alongside the borehole wall (1).