Device for hydraulically operating a drive wheel of a wellbore tractor, e.g. a motor, and related tractor, wellbore string, and method

A wireline tractor arm including a distributor for distributing hydraulic fluid in a device for operating a drive wheel of a wellbore tractor, the device comprising at least one cam and a rotatable assembly rotatable about an axis of rotation relative to the cam, the distributor comprising:

• an inner part;
• an outer part arranged around the inner part;
• and
• a chamber between the inner and outer parts;
• either the inner part or the outer part comprising at least one supply port for transmitting hydraulic fluid therethrough from the chamber to a connected piston of the rotatable assembly for energizing the piston;
• wherein the inner or outer part is movable with respect to an other of the inner and outer parts between first and second positions, for forward rotation of the rotatable assembly when in the first position and reverse rotation of the rotatable assembly when in the second position.

A method of operating a tractor in a wellbore, the tractor having at least one section comprising at least one drive wheel mounted on an end of an arm, the arm being extractable from a body of the section, and the arm including a device comprising at least one cam;

• a distributor;
• and a rotatable assembly arranged to be rotatable with respect to the at least one cam and the distributor about an axis of rotation, the rotatable assembly comprising at least one piston;
• the distributor comprising:
• an inner part;
• an outer part arranged around the inner part;
• and a chamber between the inner and outer parts;
• either the inner part or the outer part comprising at least one supply port for supplying hydraulic fluid therethrough from the chamber to the at least one piston for energizing the at least one piston, the at least one supply port being arranged to be moved between first and second positions relative to the at least one cam;
• wherein, in the first position, the at least one piston connects to the at least one supply port and be energized to impart force against the at least one cam for producing forward rotation of the rotatable assembly, and in the second position, the at least one piston connects to the at least one supply port and be energized to impart force against the cam for producing reverse rotation of the rotatable assembly, the method comprising the steps of:
• extracting the arm to push the drive wheel against a surrounding wall of the wellbore;
• supplying hydraulic fluid to the chamber of the device to generate rotation of the tractor wheel in either the forward or reverse direction corresponding to the position of the port or ports, the hydraulic fluid supplied to the chamber through the arm.

A method of configuring a wellbore tractor, the tractor having at least one section which comprises at least one device, comprising at least one cam;

• a distributor;
• and a rotatable assembly arranged to be rotatable with respect to the at least one cam and the distributor about an axis of rotation, the assembly comprising at least one piston;
• the distributor comprising:
• an inner part;
• an outer part arranged around the inner part;
• and a chamber between the inner and outer parts;
• either the inner part or the outer part comprising at least one supply port for supplying hydraulic fluid therethrough from the chamber to the at least one piston for energizing the at least one piston, the at least one supply port being arranged to be moved between first and second positions relative to the at least one cam;
• wherein, in the first position, the at least one piston connects to the at least one supply port and be energized to impart force against the at least one cam for producing forward rotation of the rotatable assembly, and in the second position, the at least one piston connects to the at least one supply port and be energized to impart force against the cam for producing reverse rotation of the rotatable assembly, the method comprising the step of:
• moving the port between the first position and the second position to set the port in either the first position for generating forward motion of the drive wheel or the second position for generating reverse motion of the drive wheel.

A device for hydraulically operating a drive wheel of a wellbore tractor, the device comprising:

• at least one cam;
• a distributor;
• a rotatable assembly arranged to be rotatable with respect to the at least one cam and the distributor about an axis of rotation, the assembly comprising at least one piston;
• the distributor comprising:
• an inner part;
• an outer part arranged around the inner part;
• and
• a chamber between the inner and outer parts;
• either the inner part or the outer part comprising at least one supply port for supplying hydraulic fluid therethrough from the chamber to the at least one piston for energizing the at least one piston, the supply port being arranged to be moved between first and second positions relative to the cam;
• wherein, in the first position, the at least one piston can connect to the at least one supply port and be energized to impart force against the at least one cam for producing forward rotation of the rotatable assembly, and in the second position, the at least one piston can connect to the at least one supply port and be energized to impart force against the cam for producing reverse rotation of the rotatable assembly;
• a coupling for transmitting rotation to the drive wheel in correspondence with the reverse or forward rotation of the rotatable assembly.

A distributor for distributing hydraulic fluid in a device for operating a drive wheel of a wellbore tractor, the device comprising at least one cam and a rotatable assembly rotatable about an axis of rotation relative to the cam, the distributor comprising:

• an inner part;
• an outer part arranged around the inner part;
• and
• a chamber between the inner and outer parts;
• either the inner part or the outer part comprising at least one supply port for transmitting hydraulic fluid therethrough from the chamber to a connected piston of the rotatable assembly for energizing the piston;
• wherein the inner or outer part is movable with respect to an outer of the inner and outer parts between first and second positions, for forward rotation of the rotatable assembly wherein the first position and reverse rotation of the rotatable assembly when in the second position;
• a locking device for locking the inner part in fixed relationship with respect to the outer part in the first or second position, wherein the locking device comprises a locking ring and a fastener for fastening the locking ring to either the inner or outer part, so that the locking ring prevents relative movement between the inner and outer parts, wherein the outer part is lockable to obtain a fixed relationship with respect to the inner part in either the first or the second position.