Low-torque centralizer

USH1192H · kind H · statutory invention registration

Assignee

• Exxon Production Research Company · US

Inventor

• Stuart R. Keller · Houston, US

Key dates

• Grant date: Jun 1, 1993

Classification

• Technology area (CPC —): General

Abstract

An improvement to a centralizer that may reduce the torque required to rotate a casing in a borehole during primary cementing is disclosed. In a first embodiment, the improvement is adapted to a bow spring type centralizer having intermediate fixed and slidable sleeves with each sleeve circumscribed by an end band. The end bands are connected to each other by a plurality of bow springs. The improvement includes interposing a sleeve bearing between each end band and its respective intermediate sleeve. The sleeve bearings may be attached to the intermediate sleeves to permit their rotation with the casing relative to the stationary end bands and bow springs. Alternatively, the intermediate sleeves may be eliminated and the sleeve bearings interposed directly between the outer surface of the casing and inner surfaces of their respective end bands.