Roller subs
AssigneeHunting Cromar Limited
InventorsFrederick Duguld McKay, Richard John Gilchrist, Colin Alexander Black
Life of this patent
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Abstract
A roller sub system for reducing friction between a tool string and a wall in a well bore for use in the oil and gas industry. The apparatus has a roller body and wheel sub system, which is configured to have removably mounted wheels of variable diameters. A plurality of different diameter wheel sets are described for mounting on the roller sub axles and orientating the system in the well bore. The wheels are fixed to the roller sub axles through a quick-release mechanism. A single apparatus can thus be employed with different diameter wheels to operate in well bores of variable diameters.
Claims12
A roller sub system for use in a tool string to reduce friction between the string and a well bore in which the string is run, the system comprising:
- an elongate body including connector means for locating the body on the string:
- and
- one or more pairs of roller wheels mounted on the body for contacting a wall of the well bore;
- wherein the body comprises a plurality of narrowed portions on a first plane parallel to a central longitudinal axis of the body through which are located respective axles perpendicular to the longitudinal axis, a pair of wheels being mounted an each axle;
- and wherein each wheel includes an outward facing substantially hemispherical surface with a circumferential edge to contact the well bore wall;
- and further wherein each pair of wheels is located on a respective axle such that the hemispherical surfaces of the wheels in each pair describe an ellipse on the first plane.
Dependencies are inferred from the claim text.