Patent Description:
Tubular drilling, reaming and running tools are mechanisms used in well bore completion services and are used to grip, rotate and reciprocate sections of tubular or an entire string of tubulars installed in an oil and gas wellbore. The engagement, dis-engagement and operation of tubular(s) can be performed mechanically using the power provided by the top drive or by using an external source of energy. One example can be found in the document <CIT>.

Conventional mechanically activated tubular drilling, reaming and running tools require a torsional reaction against the tubular to operate, engage or disengage the tool. Typically, the "bumper plate" is designed to engage the exposed face of the tubular and requires a compressive load at this interface. The friction component of this compressive load provides said torsional resistance. The ability or lack thereof for these types of tubular drilling, reaming, and running tools to develop adequate torsional resistance consistently, is dependent on many factors including set-down load, friction enhancing components, materials and inner springs.

The exposed face of the tubular is usually the female half of a threaded connection, sometimes referred to as a coupling. Depending on the frictional resistance between the coupling face and the tool has proven to be problematic because a considerably small surface area of the tubular face implies a great and sometimes dangerous set-down force required to generate adequate torsional resistance. This can cause severe damage to the tubular connection and therefore cause catastrophic failureincluding loss of life and possible loss of control of the well.

Thus, there is a need for a mechanically activated tool that is not dependent on this set down force or the frictional characteristics on the tubular connection.

In a preferred embodiment, the present inventions rely on fluid pressure to provide an alternative means to facilitate the torque reaction required to set or release slips from a pipe and eliminate the need for set down force or other frictional measures on a tubular.

One method utilized to create this reaction force relies on a series of gears interconnected with each other through a fluid driven clutch that can be engaged and disengaged. The hold back torque generated through the clutch driven system when coupled to a power screw female (threaded nut), can convert the rotational motion of the top drive to axial motion of the slips facilitating the tool to grip or release the tubular.

Another technique to create the reactionary force is to utilize a series of axial pistons attached to the moveable half of a hirth coupling, or other friction member, e.g. brake pad material or similar material used to create frictional forces between two surfaces sufficient to transfer torque. In the current inventions the preferred method is a hirth coupling. However, this is not the only device that can be used.

Shifting the torsional reaction from tool-tubular interface to the top drive-tubular running tool interface eliminates potential damage to the critical threads of boththe pin and receiving female threads of the tubular.

Both methods of the current inventions provide the reaction force (torque) from the rig's top drive system. This eliminates the need to rely on the friction created between the female end of the tubular and tool.

It will be evident with the inventions that little to no set down weight on the tubular is needed to facilitate setting or releasing the slips. The first embodiment of the current inventions utilizes a power screw (male thread) and nut (female thread). The female thread is kept from rotating via a series of gears and a fluid operated clutch. Thegear arrangement delivers a multiplication effect to the torque output of the clutch.

The clutch essentially acts as a holding brake to the female thread until the desired torque and thereby the set force on the tubular is reached. The driller can engage the clutch from the driller's cabin and re-engage at any time in case the slips need to reset on the pipe.

The clutch/gearbox assembly can achieve the reaction torque from several static components on a rig, the top drive or the bails being one such example and can be activated via fluid (hydraulic or pneumatic) or electronic activation.

Other features, aspects and advantages of the present inventions will become apparent from the following discussion and detailed description.

The foregoing summary, as well as any detailed description of the preferred embodiments, is better understood when read in conjunction with the drawings and figures contained herein. To illustrate the inventions, the drawings and figures show certain preferred embodiments. It is understood, however, that the inventions are not limited to the specific methods and devices disclosed in such drawings or figures. Further, any depicted dimensions or material selections are illustrative only and are not intended to be, and should not be construed as, limiting in any way.

Reference numbers depicted in the attached drawings correspond to the following components:.

The scope of protection of the invention is defined by the appended claims.

In the drawings, certain features well established in the graphics are omitted in the interest of descriptive clarity. Such features may include weld lines, threaded fasteners, surface finishes, etc..

<FIG> shows a specific embodiment of the current inventions in the released mode. If the tool is in the set mode and the driller wants to release the tool from the tubular, he first needs to stop rotation and set the spider. Pressure (air or hydraulic) then is applied to clutch assembly <NUM>. Once pressure has been applied, the torque is multiplied by planetary gear drive <NUM>, pinion gear <NUM> and ring gear <NUM> causing ring gear <NUM> to be held to a specific torque value. This gear train mechanism is shown in <FIG>.

<FIG> shows the transmission of torque through ring gear sleeve <NUM> onto female spline ring <NUM>. The female spline <NUM> is rigidly attached to power screw female <NUM>.

Once the clutch is engaged, the top drive can now turn counterclockwise in order to release the slips. Once the top drive turns counterclockwise, the power screw male <NUM> turns with the tool body <NUM> through the torque key(s) <NUM>. This torque is translated into axial force through the power screw female <NUM>. Push plate <NUM> does not rotate due to engagement with push plate bearings <NUM> and <NUM> while the top drive rotates.

Pressure on clutch assembly <NUM> must be present the entire time the tool is releasing or setting in order for the tool to deliver the holding torque required to the power screw female <NUM>. When the tool is in operation, clutch assembly <NUM> is released and freely rotates.

<FIG> shows a specific embodiment of the current inventions in the set mode. If the tool is in the released mode and the driller wants to set the tool on the tubular to make-up a joint, pressure must be applied to clutch assembly <NUM>. The torsional force applied by the top drive is transmitted through the planetary gear drive <NUM>, pinion gear <NUM> and ring gear <NUM> through to the ring gear sleeve <NUM> and further to female spline ring <NUM>. The female spline <NUM> is rigidly attached to power screw female thread <NUM>. Once the clutch is engaged the driller can now rotate the top drive clockwise to set the slips.

The top drive rotates clockwise which turns the power screw male thread <NUM> with the main tool shaft <NUM> through the torque key <NUM>. The torque keys <NUM> allow the power screw male thread <NUM> to rotate at the set top drive torque to set the tool to the correct axial force. This torque is translated to axial force through the power screw female thread <NUM>. The push plate <NUM> pushes the slips <NUM> through the main slip push bars <NUM> and secondary slip push bars <NUM> onto the pipe. This axial force pushing down on the slips <NUM> allows sufficient gripping force to resist rotational and axial load on the tubular.

<FIG> illustrates the tool being set on the tubular, ready for make-up. During make-up, clutch assembly <NUM> is released, the reaction torque is gone, and all the bearings are free to rotate. The tool transmits the top drive torque through to the tubular. When the tubular is made up, the top drive lifts the tubular and the slips on the rig floor are released. The tool can now be used as a running, drilling or reaming tool. The tool itself is not fluid actuated, but rather mechanically actuated, so there are no speed restrictions on rotating, except for the speed limitations of the top drive system ofthe rig.

An alternate method that can be used with the current inventions has a piston driven moveable hirth coupling transferring the reaction force onto the female nut of the power screw. This enables the movement of the slip assemblies to engage or dis-engage from the pipe. Once the engagement I disengagement is complete, the pressure to the actuator is relieved and the hirth coupling is disengaged by way of the spring assemblies pulling the hirth out of engagement automatically.

In this embodiment, the torque reaction of the female nut of the power screw is provided by the bails via the anti-rotation deck. This plate meets bails which act as a back stop for the reaction of the screw nut being screwed together. The anti-rotation deck is the preferred method, but not the only method. A bracket could also loosely grip the outside of the gripper box, or the top plate could be anchored to the gripper box with a bolt on bracket.

<FIG> illustrates another embodiment of the fluid controlled mechanical casing running tool. This embodiment utilizes a movable hirth coupling half <NUM> and alower fixed hirth coupling half <NUM>.

With fluid power, the movable hirth half <NUM> is forced to mate with the lower fixed coupling half <NUM>. This action makes the two halves come together and become torsionaly mated. This couples the anti-rotation deck <NUM> with the female power screw thread <NUM> which enables the deck to be held against the top drive's bails. This restricts tool rotation while the top drive is in use, rotating the power screw <NUM>. With thefemale power screw thread <NUM> held, it traverses down the male power screw thread <NUM>. Trunnion slots <NUM> keep the trunnions located (not shown) on the female nut from rotating. This converts rotational torque into axial force, moving the slip push plate carrier <NUM> which will set or release the slips depending on rotation (clockwise to set and counterclockwise to release).

Once the slips are set or released, the fluid actuated movable hirth is released, and the return springs <NUM> pull the movable hirth out of harm's way.

<FIG> depicts a specific embodiment of a fluid actuator of the current inventions. The actuator assembly may consist of a plurality of fluid pistons <NUM> that provide the axial force to forcethe movable hirth coupling half <NUM> into engagement with the fixed hirth coupling half <NUM>. The return springs <NUM> compress against the spring retaining bolt <NUM> when the fluid pistons <NUM> are energized. Once the actuator is de-energized, the compressed return springs <NUM> return to a relaxed state, pulling the movable hirth coupling half <NUM> out of engagement with the lower fixed hirth coupling half <NUM>.

Torque resisted by the anti-rotation deck <NUM>, is transmitted through the movable hirth coupling half <NUM> with the help of the torque pins <NUM>. The torque pins <NUM> move in an axial plane with the movable hirth coupling half <NUM>. The air breather ports <NUM> prevents build up of gas behind torque pins <NUM> when moving axially. The fluid pistons <NUM> receive the fluid through the fluid port <NUM> and fluid supply galley <NUM>. The fluid port is sealed by the static seal ring <NUM> which in turn are sealed by the static O-ring seals <NUM>.

The gripper box extend port, as well as any other usable ports on the rotary joint manifold (not shown), supplies the fluid axial piston assembly <NUM> with fluid. However other sources of fluid power mounted internally on the casing running tool or external to the casing running tool can be used to provide fluid to either method of operating the tool. A regenerative system using fluid from a reservoir or an external power unit are examples of such sources.

<FIG> illustrates the lower fixed hirth coupling half <NUM>, a toothed flat spline plate that can engage a mating part and provide a torsional stiff coupling.

Claim 1:
An apparatus for transferring torque comprising:
a main tool body (<NUM>);
a main tool shaft (<NUM>) disposed in the main tool body (<NUM>);
a power screw male thread (<NUM>) disposed around the main tool shaft (<NUM>), and configured to turn with the main tool shaft (<NUM>);
a power screw female thread (<NUM>) movably engaged with the power screw male thread (<NUM>);
a gear assembly (<NUM>) connected to the power screw female thread (<NUM>);
a clutch (<NUM>) connected to the gear assembly (<NUM>), the clutch (<NUM>) having an engaged position and a disengaged position, the clutch and gear assembly configured to cooperate to restrict rotation of the power screw female thread (<NUM>) when the clutch (<NUM>) is in its engaged position, the clutch and gear assembly configured to cooperate to permit rotation of the power screw female thread (<NUM>) when the clutch (<NUM>) is in its disengaged position; and
a set of slips (<NUM>) connected to the main tool body (<NUM>), the set of slips (<NUM>) having a set position in which the set of slips (<NUM>) are adapted to engage a tubular member, the set of slips (<NUM>) having a released position in which the set of slips (<NUM>) are adapted to disengage from the tubular member, the set of slips (<NUM>) being moved into the set position when the clutch (<NUM>) is in its engaged position and the main tool shaft turns in one direction, and the set of slips (<NUM>) being moved into the released position when the clutch (<NUM>) is in its engaged position and the main tool shaft turns in the opposite direction.