Boring or penetrating the earth – With tool drive prime mover or above-ground mechanical...
Patent
1996-11-27
1998-09-08
Bagnell, David J.
Boring or penetrating the earth
With tool drive prime mover or above-ground mechanical...
166 771, 1662425, F21B 1908, F21B 33072
Patent
active
058031910
DESCRIPTION:
BRIEF SUMMARY
This invention relates to well or borehole drilling equipment having means for handling wireline equipment and similar flexible elongate equipment which may be inserted into a well or borehole.
The use of wireline instruments for well inspection and logging is well known. Conventionally, however, the use of wireline instruments necessitates the removal of the derrick mud hose to permit entry of the wireline. This has the result that drilling mud cannot be circulated during use of the wireline, with consequent risk of well blow-out. There is also the consequence that the mud pump cannot be used to drive the wireline tool through the well bore, which would be desirable for example in highly deviated wells.
There are also problems in the conventional method of feeding wireline into the drill string through the top drive motor housing, since this involves passing the wire through a tight angle which interferes with ready feeding of the wire.
Accordingly, the invention provides a well entry tool comprising an upper tubular member and a lower tubular member connected together by an intermediate assembly; the upper and lower tubular members being provided with outer end portions for connection of the tool in a drill string for fluid flow therethrough; the intermediate assembly comprising a hollow body including axially aligned, spaced bearing devices receiving the upper and lower tubular members to provide rotation of the tubular members relative to the hollow body, a power transmission mechanism within the hollow body for transmitting torque from the upper tubular member to the lower tubular member, and an entry device allowing a flexible elongate member to pass sealingly from the exterior to the interior of the hollow body.
The elongate member may be a wireline, coil tubing or any other flexible elongate member which it is desired to insert into a borehole or well.
Preferably, the hollow body comprises a tubular outer housing and a pair of end plates.
The bearing means may be mounted in the end plates.
The power transmission mechanism suitably comprises respective annular cogs secured to the inner ends of the tubular members and interconnected by means of meshing cogs mounted on one or more layshafts.
Preferably, three layshafts are used, which are equispaced circumferentially of the tool. The layshafts may conveniently be rotatably mounted on the end plates.
In an alternative arrangement, each layshaft is associated with an intermediate layshaft providing an additional cog, whereby the upper and lower tubular members rotate in opposite directions.
The entry device preferably comprises a passage through the upper end plate aligned at an acute angle to the bore of the lower tubular member. Typically, the acute angle is a shallow angle. Preferably, the tool is used for wireline and the entry means forms a wireline entry means. Said passage may be provided by a grease tube threadedly secured in an angled bore in the upper end plate. The grease tube is preferably provided at its outer end with a pack-off.
The grease tube may optionally be contained within an outer tubular member for additional strength and safety. The wireline will typically enter the outer tubular member via a stuffing box.
The outer housing is preferably securable to a tie rod assembly adapted for fixing, for example, to the bail arms of a drill rig.
The invention, from another aspect, also provides a grease tube for use in the foregoing tool, the grease tube comprising two longitudinal tube halves releasably secured together to define a bore for passage of a wire. The tube halves may be secured together by interengageable lugs and slots, which preferably exert a wedging force. Preferably, the tube halves are provided with external formations which, when the tube halves are secured together, form means (for example a screw thread) for securing the grease tube to a wireline entry tool as defined above.
The grease tube may further be provided with an outer tubular member, which may be provided at one end with a stuffing box.
An advantage of the inv
REFERENCES:
patent: 1509906 (1924-09-01), Sawtelle
patent: 2815969 (1957-12-01), Lebourg
patent: 4681162 (1987-07-01), Boyd
patent: 5284210 (1994-02-01), Helms et al.
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