The present invention provides a device and a method for manipulating tubular segments for make up and installation of a tubular string in a well.

Tubular strings installed in wells are made up by threadably coupling individual tubular segments at a well site. For example, a string of drill pipe is made from threadably coupling joints of drill pipe to rotate and advance a drill bit downhole. A casing string is made up by threadably coupling casing segments to line a drilled borehole to prevent collapse and to facilitate cementing. A production string is made up and run through casing strings to provide a conduit from the formation to the surface for producing oil or gas.

Valuable rig time is consumed in retrieving, positioning and threadably coupling segments of pipe into a string. Since hundreds of segments may be made up and run into a borehole, saving just seconds per connection results in a substantial savings in rig time.

The amount of time required to engage and rotate the pipe segment and make up the threaded connection to the pipe string is only a portion of the rig time consumed in making a connection. The time consumed in obtaining and positioning each add-on segment atop the string for make up is determined in part by the efficiency of tools used to retrieve and manipulate the segment.

Tools are available for manipulating and positioning segments for make up into a string. Existing tools typically consist of a single joint elevator suspended by a rope slung beneath a main string elevator. Suspending the single joint elevator by a rope imposes many limitations on the efficiency of the process of adding pipe segments to the pipe string. These existing systems require rig personnel to swing or carry the single joint elevator to the receiving door and place it onto the pipe segment to be added onto the string. Also, once the pipe segment is coupled to the rope and hoisted above the rig floor, the pipe segment will generally not hang vertical due to the force of gravity, and it is difficult and awkward to maneuver the pipe segment into a vertical position atop the pipe string suspended in the borehole. Finally, once the pipe segment is threadably coupled to the pipe string in the borehole, the single joint elevator must be removed from the path of the string elevator or top drive, and rig personnel are required to carry the elevator back to the receiving door or other location on the rig floor.

An improved method and apparatus are needed for manipulating segments to be made up into a pipe string. The method and apparatus would preferably provide more precise, safe and efficient manipulation of segments and save time in making up the string. The apparatus would preferably be light-weight, so that it can be easily removed from the path of the string elevator or top drive, but sufficiently robust to support and manipulate tubular segments.

GB2340858A discloses an apparatus for facilitating the connection of tubulars using a top drive. The apparatus comprises an elevator provided on bails which are hanged from the top drive. A pair of piston and cylinders are arranged between the bails and the top drive for moving the elevator from below the top drive to an out of the way position. This document is considered the closest prior art and corresponds to the preamble of claim 1.

US 2005/098352 A1 discloses a pipe handling device for use with a top drive. The device comprises a link arm having a first end pivotally connectable to move with the top drive and an outboard end pivotally connectable to a pipe elevator segment, and a drive system to drive the outboard end of the link arm at least between a lower position and a raised position.

US 4,489,794 discloses an apparatus having an elevator supported by elevator links which are hanged from a derrick. The apparatus further comprises a power actuated means for swinging the lower ends of the elevator links laterally so as to shift the suspended elevator to a side of the well axis.

US 2004/216924 A1 discloses an apparatus having a clamping head for engagement with a tubular. The clamping head is mounted on a pair of mechanical bails which are hanged from the top drive. A pair of pistons and cylinders are arranged between the bails and the top drive to swing the bails. Upon swinging the bails, the clamping head also swings to the side of the connection location so as to align with a tubular that is to be added to the string.

In accordance with an aspect of the present invention there is provided an apparatus for manipulating tubular segments for being made up into a tubular string, the apparatus having the features of claim 1 below.

One embodiment of the present invention comprises a single joint manipulator arm having a swing arm supporting a single joint elevator for securing a pipe segment to the swing arm. The swing arm is a strong and generally light-weight arm positionable with one or more cylinders or other actuators for rotatably aligning the segment with the string. In a first embodiment, the present invention provides a single joint manipulator arm that is pivotably securable to one or more bails that support a string elevator for lifting and lowering the pipe string into the borehole after each joint or stand of new pipe is threadably coupled into the string. The present invention provides a light-weight single joint manipulator arm that is easily and efficiently removed from the path of the string elevator or spider elevator. In a second embodiment, the present invention provides a single joint manipulator arm that is pivotably securable to a sub threadably coupled to a top drive shaft or quill. In this embodiment, the manipulator arm is pivotably secured to the sub above other components, such as a fill-up and circulation tool, or it is pivotably secured to a sub positioned below a top drive shaft and above a casing running tool.

Fig. 1 is a side elevation view of one embodiment of a single joint manipulator arm of the present invention in its aligned position and suspended from the bails on a rig.

Fig. 2 is a side elevation view of the single joint manipulator of Fig. 1 in its removed or "luffing" position.

Fig. 3 shows the single joint manipulator arm of Fig. 1 coupled to a casing segment at the staging area.

Fig. 4 shows the single joint manipulator arm of Fig. 1 after the bails and the string elevator are elevated and the single joint manipulator arm and casing segment controllably rotated clockwise from its position shown in Fig. 3.

Fig. 5 is a side elevation view of the single joint manipulator arm of Fig. 1 after the bails and the string elevator are elevated from the position in Fig. 4, and the single joint manipulator arm and casing segment controllably rotated further clockwise to suspend the casing segment adjacent to the axis of the well.

Fig. 6 is a side elevation view of the single joint manipulator arm of Fig. 1 after being rotated further clockwise from its adjacent position shown in Fig. 5 to generally suspend the segment in a vertical position aligned with the string in the well.

Fig. 7 is a side elevation view of the single joint manipulator of Fig. 1 illustrating a safety fuse used for preventing tool failure from excessive load being applied.

Fig. 8 is a perspective view of the single joint manipulator arm of Fig. 1 showing a bifurcated pivoting attachment to the bails and powered rotation using a pair of actuators.

Fig. 9 is a perspective view of a modified lower portion of the single joint manipulator arm of the present invention comprising a slew actuator for angular displacement of the stand-offs to position a tubular segment secured within the single joint elevator.

Fig. 10 is a perspective view of an alternative embodiment of the single joint manipulator arm of the present invention pivotably supported by a sub that is threadably coupled to and suspended from a top drive. The sub also supports a casing running tool that is operated by the top drive to releasably engage and support the pipe string and a fill-up and circulation tool.

Fig. 11 is a perspective view of another alternative embodiment of the single joint manipulator arm of the present invention pivotably supported by a sub that is threadably coupled to and suspended from a top drive. The sub supports a fill-up and circulation tool that is aligned with the top drive and positioned to enter the proximal end of a pipe string secured within the string elevator.

Fig. 12 is a high-level method flowchart describing one embodiment of a method of the present invention.

The present invention provides an apparatus and method for manipulating casing segments to assemble a casing string in a borehole. A single joint manipulator arm may be used to safely and reliably manipulate casing segments as they are made up into a casing string and installed in a well. The embodiments disclosed below describe the manipulation of casing segments to assemble a casing string using the present invention. It is to be understood, however, that other types of tubular segments, including drill pipe and production tubing, may be similarly manipulated to assemble strings without departing from the scope of the invention. For the reason, the terms "pipe", "tubular" and "casing" are used interchangeably, as are the terms "segment" and "joint."

In one embodiment, an apparatus and method of the present invention are used to assemble and run a casing string. Once assembled, the casing string will include a plurality of casing segments threadedly coupled end-to-end and installed in a well. The rig on which this embodiment may be used includes a hoist movably suspending a pair of bails that, in turn, suspend a string elevator. A swing arm, having a proximal end, and a distal end is pivotally coupled at its proximal end to the bails at a location above the string elevator. The swing arm supports a single joint elevator at its distal end, which may be a hinged-body type elevator or a horseshoe elevator. The pivoting swing arm is angularly positionable relative to the bails using one or more actuators, such as cylinders. Control of the swing arm and the hoist enable the operator to efficiently retrieve a casing segment from a staging area and to move the casing joint into abutting alignment with the string for being threadably coupled into the string.

A segment of large casing to be lifted using the manipulator arm may weigh 2,000 pounds (980 kg). A casing string may weigh 400,000 pounds (181,600 kg). The string elevator is very heavy compared to the single joint manipulator arm, and the moment imposed on the bails by the light-weight single joint manipulator arm and the casing segment do not significantly deflect the string elevator and the heavy bails from the vertical orientation.

Fig. 1 is a side elevation view of one embodiment of a single joint manipulator arm 10 the present invention. A perspective view of this same embodiment is shown in Fig. 8. A string elevator 12 is secured to a pair of bails 14, 114 at lifting ears 16, 116. The string elevator 12 is sized and configured for coupling to and supporting a casing string by securing the proximal end of the casing string (not shown in Figs. 1 or 8 - see element 36 in Figs. 3-6). The bails 14, 114 are configured for supporting the weight of the string elevator and the casing string, and are coupled at their supported ends to a block suspended by a draw works (not shown).

The single joint manipulator arm 10 of the present invention comprises a swing arm 18 pivotally coupled at swing arm pivots 28b, 128b to bails 14, 114. The swing arm 18 includes an upper portion 20 that forms an angle to the swing arm and provides offset clearance around the string elevator 12 when the swing arm 18 is generally vertical (see Fig. 6). Single joint elevator 22 is supported from stand-off members 52 and 152 pivotally coupled to the distal end 17 of the swing arm 18 for releasably securing and supporting a casing segment (not shown in Figs. 1 and 8 see Figs. 3-6).

Typically, an internally threaded coupling is used to threadably couple two casing segments end-to-end. This coupling structure provides an external circumferential shoulder that a single joint elevator 22 may engage to support the add-on casing segment. However, it is within the scope of the present invention to use a single joint elevator adapted for securing integral connection segments by clamping along the length of the body of the pipe segment in place of the horseshoe elevator shown in Fig. 1 or the hinged-body type elevator shown in Fig. 9. The string elevator, horseshoe elevator and hinged-body type elevator shown in the drawings are included in the disclosed embodiment of the present invention for illustration only.

The generally light-weight swing arm 18 of the single joint manipulator arm of the present invention may be extendable, such as by axially telescoping. As shown in Figs. 1 and 8, the length of the swing arm 18 may be adjustable in length by telescoping an inner beam member 26 from within an outer beam member 24, then securing the outer and inner beam members 24, 26 by, for example, inserting a pin 28 through a pair of alignable holes 27. The use of tubular or squared tubular steel may provide a good strength to weight ratio.

The swing arm 18 is controllably rotatable about the pivots 28b, 128b using an actuator, such as a pair of pneumatic or hydraulic cylinders 21, 121. The cylinders 21, 121 each comprise a piston (not shown) coupled to selectively extendable and retractable rods 23, 123, respectively, that are axially positionable with respect to cylinders 21, 121. The rods 23, 123 in Figs. 1 and 8 are shown in the extended condition to position the swing arm 18 in a substantially vertical position generally parallel to the bails 14, 114.

Fig. 2 is a side elevation view of the single joint manipulator arm 10 in a substantially horizontal or luffing position. The rods 23 and 123 (the latter not shown in Fig. 2) are shown retracted into the cylinders 21 and 121 (the latter not shown in Fig. 2) to position the swing arm 18 generally perpendicular to the bails 14 and 114 (the latter not shown in Fig. 2). The luffing position illustrated in Fig. 2 serves two purposes. Casing segments are sometimes presented to the rig floor at a receiving door in a substantially horizontal condition. The luffing position shown in Fig. 2, or a position near horizontal, may be suitable for coupling the elevator 22 supported by the single joint manipulator arm 10 to casing segments presented in this condition. Also, the luffing position removes the single joint manipulator arm 10 and the supported elevator 22 from obstructing the full descent of the string elevator 12 (or, in other embodiments, a casing running tool or a top drive) as it lowers a casing string into the borehole after an add-on casing segment is made up into the casing string.

Receiving doors, or staging areas, on some rigs present add-on pipe segments to the rig floor in a position angled between vertical and horizontal (see Fig. 3). In use on these rigs, the cylinders 21 and 121 (the latter not shown in Fig. 3) may be used to position the elevator 22 supported by the single joint manipulator arm 10 to a suitable angled position between vertical and horizontal for coupling to the presented casing joint 30. When the single joint manipulator arm 10 is moved to the desired initial position, a presented casing segment 30 is secured to the single joint manipulator arm 10 at the presented end 32 by securing the segment in the single joint elevator 22.

Figs. 3-6 are sequential side elevation views of the single joint manipulator arm 10 of Fig. 1 showing the process of manipulating a casing segment from an initial position in a staging area (Fig. 3) to an aligned position for rotatably coupling to a casing string in a well (Fig. 6). To retrieve a casing segment from the staging area of a rig, an actuating member first moves the swing arm outwardly away from vertical to position an end of the swing arm in proximity to a staging area wherein casing joints are presented. Fig. 3 shows one embodiment of the single joint manipulator arm 10 in an initial position for retrieving a casing segment 30 from a rig staging area 35. The horseshoe elevator 22 is engaged just below a collar 32 of the presented casing segment 30. Once the segment is secured to the swing arm 18, the hoist raises the bails 14, 114 (the latter not shown in Fig. 3) the swing arm 18 and the casing segment 30. As the casing segment 30 is raised, it slides along ramp 37, and the swing arm 18 controllably rotates in the clockwise direction against the damping force of cylinders 21 and 121 (the latter not shown in Fig. 3). This clockwise rotation of the swing arm 18 against the damping force controllably moves the casing segment 30 in the direction of the casing string 34 (see Fig. 6). A damping member, such as a hydraulic, pneumatic or inert gas-charged cylinder, is used to dampen and control movement of the swing arm as it rotates from the initial position the equilibrium position. The damping member provides controlled and manageable movement in manipulating the casing segment.

Fig. 4 is a side elevation view of the single joint manipulator arm 10 of Fig. 3 showing the bails 14 and 114 (the latter not shown in Fig. 3) elevated from their initial position shown in Fig. 3, and the single joint manipulator arm 10 rotated further clockwise against the damping force of the cylinders. The casing segment 30 in Fig. 4 is shown substantially raised along ramp 37 from its initial position shown in Fig. 3. As the bails 14 and 114 (the latter not shown in Fig. 3) raise the single joint manipulator arm 10 and the casing segment 30 along ramp 37 in staging area 35, the weight of the casing segment 30 increasingly urges the swing arm 18 to rotate clockwise. The cylinders 21 and 121 (the latter not shown in Fig. 4) dampens the rate of clockwise swing of the swing arm 18, and the damping action provided by cylinders 21 and 121 will prevent rapid or uncontrolled swing of the casing segment 30 across the rig floor after the casing segment 30 clears the ramp 37.

Fig. 5 is a side elevation view of the single joint manipulator arm 10 of Figs. 3 and 4 showing the bails 14 and 114 (the latter not shown in Fig. 5) raised from the position shown in Fig. 4 and the swing arm 18 rotated further clockwise from its position shown in Fig. 4. The casing segment 30 shown in Fig. 5 hangs from single joint elevator 22 substantially vertically in an equilibrium position, but it is not aligned with the casing string 34 in the well supported by the spider 36 because of the offset provided by the angled portion 20 at the top of the swing arm 18. As shown in Fig. 5, this equilibrium position is not aligned with the casing string 34, and the casing segment 30 hangs offset from alignment with the top connection with the casing string 34. The casing segment 30 hangs slightly suspended from the single joint elevator 22 like a pendulum, and the single joint elevator 22 imparts generally negligible torque on the casing segment 30. The equilibrium position of the swing arm 18 shown in Fig. 5 and the amount of offset is determined by the dimensions and weights of both the single joint manipulator arm 10 and the casing segment 30 when cylinders 21 and 121 (the latter not shown in Fig. 5) are inactive. Since the casing segment 30 is generally significantly heavier than the swing arm 18, the casing segment 30 will generally hang near vertically below the pivots 28b and 128b (the latter not shown in Fig. 5) securing the pivot arm 18 to the bails 14 and 114 (the latter not shown in Fig. 5).

Fig. 6 is a side elevation view of the single joint manipulator arm 10 of Figs. 3-5 with the casing segment 30 vertically positioned above and axially aligned with the casing string 34, positioned to be lowered by the hoist (not shown in Fig. 6) to engage the casing string 34. The swing arm 18 has been rotated slightly further clockwise from its equilibrium position shown in Fig. 5 by energizing the cylinders 21 and 121 (the latter not shown in Fig. 6) to extend the rods 23 and 123 (not shown in Fig. 6) to rotate the swing arm 18 from its equilibrium position of Fig. 5 to the aligned position shown in Fig. 6. Energizing the cylinders 21, 121 to extend the rods 23, 123 rotates the swing arm 18 further clockwise from its position shown in Fig. 5 and slightly vertically lifts the casing segment from its equilibrium shown position of Fig. 5 as it vertically aligns the single joint elevator 22 and the casing segment 30 with the casing string 34. The capacity to rotate the single joint manipulator arm 10 clockwise from its equilibrium position shown in Fig. 5 provides substantially all of the rotational movement required to position casing segment 30 may be alignment with the casing string 34. A lower, distal end 33 of the casing joint 30 is positioned to be threadably coupled with the proximal end of casing string 34. The string elevator 12 is substantially axially aligned with casing string 34 so that the hoist (not shown) and bails 14 and 114 may be lowered, along with the string elevator 12, to provide abutting contact for casing make up.

Once the casing segment 30 has been brought into aligned contact with the casing string 34, a power tong or other torquing device engages and axially rotates casing segment 30 to make up the threaded connection between the casing segment 30 and the casing string 34. After the connection is made, the single joint elevator 22 is released from the casing segment 30 and the swing arm 18 is rotated counterclockwise using cylinders 21 and 121 to its luffing position shown in Fig. 2. The hoist (not shown in Fig. 2) and bails 14 and 114 may then be lowered to bring the string elevator 12 to the proximal end 32 of the casing joint 30. The string elevator 12 may be engaged with the proximal end 32 of the casing segment 30, and the entire casing string 34 is lifted by the hoist (not shown) and the string elevator 12 to allow disengagement of the spider 36. The string elevator 12 is then lowered until the proximal end 32 of the casing segment 30 reaches the same elevation as previously occupied by the proximate end of the casing string 34 shown in Fig. 6. The spider 36 is then engaged to support the casing string 34 in the well, and the string elevator 12 may be disengaged from the casing segment 30.

The process described above in connection with Figs. 3-6 is repeated with additional casing segments until the casing string 34 achieves the desired length.

To further enhance safety, the apparatus may include a safety fuse, such as a shear pin, that will audibly shear if the swing arm supports a load that is substantially heavier than a segment of the casing being made up and run into the well. Fig. 7 is a side elevation view of one embodiment of the single joint manipulator arm 10 for illustrating a load safety fuse 50. A pair of stand-offs 52, 152 (the latter not shown in Fig. 7) are secured at their first ends 52a, 152a (the latter not shown in Fig. 7) to the lower portion 17 of the swing arm 18 at pivot 54. A sacrificially failing safety link 58 is pivotally coupled to the swing arm 18 at pivot 58a located generally intermediate the pivotal coupling 54 of the stand-offs 52, 152 and angled portion 20. The safety link 58 is coupled between pivot 58a and shackle 57 which is, in turn, coupled to the first ends 56a, 156a of cables 56 and 156 (elements 156a and 156 not shown in Fig. 7 - see Fig. 8). The second ends 56b and 156b of cables 56 and 156 are coupled and supported to the second ends 52b and 152b of stand-off members 52 and 152. The safety link 58 generally is held by stand-offs 52, 152 at an angle to the swing arm 18. As shown in Fig. 7, that angle is about 20 degrees, with the stand-offs 52, 152 being supported substantially in positions perpendicular to the swing arm 18. The weight of the single joint elevator 22 biases the stand-offs 52, 152 generally downwardly when the single joint manipulator arm 10 is vertical, pulling cables 56 and 156 taut.

The safety link 58 comprises a sacrificially failing member that is designed to fail under a predetermined load. Thus, the safety link 58 is designed to withstand the load produced in cables 56 and 156 when the weight of segment of casing is supported by the single joint elevator 22. A load significantly heavier than that of a casing segment plus the elevator 22 will cause the sacrificial member to fail, such as a shear failure, without dropping the load. The sound of the sacrificial failure is loud enough to alert the rig operator. In response to the sacrificial failure of the safety link 58, the stand-offs 52, 152 will slightly rotate about pivot 54 counterclockwise (in Fig. 7) but will remain coupled by safety link 58 to avoid dropping the casing segment coupled to the single joint elevator 22.

Fig. 8 is a perspective view of the embodiment of the single joint manipulator arm 10 in Figs. 1-7. The lifting ear 16 on the bail 14 is accompanied by a second lifting ear 116 on bail 114. These bails are movably suspended from a block (not shown), and are capable of supporting very heavy loads, such as a casing string. The angled portion 20 of the swing arm 18 comprises a pair of generally parallel prongs 18a, 18b that are pivotally coupled to bail clamps 29, 129, respectively, at swing arm pivots 28b, 128b, respectively. The bail clamps 29, 129 are secured to bails 14, 114, respectively, using fasteners. The hydraulic cylinder 21 is accompanied by a second generally parallel hydraulic cylinder 121 for balanced damping of swinging loads applied to swing arm 18. The cylinders 21 and 121 comprise extendable and retractable piston rods 23, 123 that are pivotally coupled to swing ears 25, 125, respectively, of the swing arm 18. Cylinders 21, 121 are each pivotally coupled to bail clamps 29, 129, respectively, at pivots 28a, 128a, respectively. These pivoting cylinder couplings on bail clamps 29, 129 are each secured to the bails at a spaced distance above swing arm pivots 28b, 128b that pivotally secure the prongs 18a, 18b of swing arm 18 to the bail clamps 29, 129, respectively. The swing ears 25, 125 are offset from the swing arm so that pivoting of the swing arm 18 toward its equilibrium position (see Fig. 5) under the force of gravity rotates the swing ears 25, 125 away from the cylinders 21, 121 and requires substantial extension of the rods 23, 123 from cylinders 21, 121, respectively, for rotation. The resistance to extension of the rods 23, 123 from cylinders 21, 121 substantially dampens the rate of rotation of the swing arm 18 as compared to unrestrained swinging of the swing arm 18. Similarly, force imposed by powered retraction of rods 23, 123 into the cylinders 21, 121 pulls against swing ears 25, 125, respectively, to controllably rotate the swing arm 18 to the desired angular orientation, either to an initial position (see, for example, Fig. 3) for coupling the single joint elevator 22 to a presented casing segment 30, or to the luffmg position (see Fig. 2) for either coupling the single joint elevator to a horizontally presented casing segment or for removing the swing arm 18 from obstructing the descent of the string elevator 12 to the spider 36.

In the embodiments discussed in connection with Figs. 1-8, hydraulic cylinders 21, 121 provide a dual function. According to a first function, the cylinders 21, 121 substantially slow and dampen movement of the swing arm 18 under the load of a casing segment secured in the elevator 22 as the single joint elevator and the load is lifted from a staging area. According to a second function, cylinders 21, 121 are used as actuators to rotate the swing arm 18 beyond its equilibrium (shown in Fig. 5) to selectively position the swing arm 18 and thereby align the casing segment with the casing string, and also to rotate the swing arm 18 to the luffing position or to an angle for securing the elevator to a presented casing segment. Other embodiments may employ independent devices to actuate the swing arm 18 to align with the casing string and to dampen movement of the swing arm under load. For example, it is within the scope of the present invention for one cylinder may be used as an actuator to rotate the swing arm and another cylinder may used to dampen swing rotation of the swing arm.

As previously mentioned, the swing arm 18 may comprise a telescoping portion. The outer beam 24 may slidably receive an inner beam 26. In other embodiments, a swing arm may be axially extendable without these beams being concentric as in the embodiments of Figs. 1-8. For example, it is within the scope of the present invention for one beam to secure to the other using a slot on one beam and a bolt or pin on the other beam that is receivable and securable within the slot to lock the beams together to form a single load-bearing member.

An advantage of an extendable swing arm is that it provides the ability to adjust the length of the swing arm to manipulate different lengths of casing segments, to adjust the single joint manipulator arm to cooperate with the height of the spider at the rig floor, or generally to accommodate different drilling rig configurations. Additional versatility is realized by use of the embodiments of the tool of the present invention shown in Figs. 9-12. The single joint manipulator arm can be adapted for use with fill-up and circulation tools, pipe gripping assemblies and slew actuators that enhance the capacity of the tool to manipulate and position tubular segments for make-up into a tubular string.

Fig. 9 is a perspective view of a modified lower portion of the single joint manipulator arm of the present invention comprising a slew actuator for angular displacement of the stand-offs to position a tubular segment secured within the single joint elevator. Fig. 9 shows an alternate embodiment of the single joint manipulator arm 10 of the present invention having enhanced capacity to manipulate and position tubular segments supported in the single joint elevator 22. Fig. 9 shows a lower portion 20 of the single joint manipulator arm of the present invention equipped with a slew actuator. A pair of stand-offs 52 and 152 are pivotally secured at their first ends 52a, 152a (the latter not shown in Fig. 9) to the lower portion 17 of the swing arm 18. The second ends 56b and 156b of cables 56 and 156 are coupled to the second ends 52b and 152b of stand-offs 52 and 152. The stand-offs 52, 152 are supported by cables 56 and 156 in positions generally perpendicular to the swing arm 18. The weight of the single joint elevator 22 and any tubular segment secured therein biases the stand-offs 52, 152 generally downwardly when the single joint manipulator arm 10 is vertical, thereby pulling cables 56 and 156 taut.

The enhanced capacity for manipulation and positioning of tubular segments provided by the slew actuator shown in Fig. 9 is best understood by consideration of the ranges of controlled movement, relative to a classic x-y-z three-dimensional coordinate system, provided by the single joint manipulator arm. As seen in Figs. 3 - 6, the cylinders 21 and 121 provide controlled rotation of the swing arm 18 and the supported casing segment 30 in the x-y plane. This movement of the tubular segment 30 secured in the elevator 22 is primarily along the x-axis when the cylinders 21 and 121 position the swing arm 18 in the generally vertical orientations shown in Figs. 5 and 6. Vertical displacement of the tubular segment secured in the elevator 22 along the y-axis is provided by the rig hoist (not shown) that raises and lowers the drawworks, block and the sub and/or bails to which the single joint manipulator arm is secured. The slew actuator shown in Fig. 9 provides for controlled movement along the z-axis.

Fig. 9 shows the components of one embodiment of the single joint manipulator arm equipped with a slew actuator providing enhanced positioning and manipulation of the suspended tubular joint. The slew actuator housing 42 generally surrounds a slew actuator 43, which may be a cylinder, for positioning a slew rod 44 generally perpendicular to the pivotable stand-offs 52 and 152. While the actual movement of stand-offs 52 and 152 is radial about stand-off pivots 46a and 46b, respectively, the movement of a tubular segment (not shown in Fig. 9) secured in the elevator 22 upon actuation of the slew actuator 43 is substantially along the z-axis as defined above. Accordingly, this embodiment of the present invention provides superior control and manipulation of casing segments for being made up into a casing string.

Fig. 10 is a perspective view of one embodiment of the single joint manipulator arm 10 of the present invention secured to and supported by a top drive and supporting a fill-up and circulation tool and a pipe gripping assembly. The single joint manipulator arm 10 is pivotably secured to an enlarged portion of a sub 88 that is threadably coupled at its inlet 88a (above the sub 88) to a top drive and supports a casing running tool 104 from its discharge 88b (below the sub 88). In this embodiment, the discharge 88b of the sub 88 supports a casing running tool 104 having a gripping assembly sized for being received into a casing segment (not shown). The casing running tool 104 comprises a plurality of pipe gripping shoes 105 that are deployable and retractable radially outwardly to grip and release the internal wall of a casing segment to support the casing string or to rotate the casing segment to make up the connection with the casing string.

The embodiment in Fig. 10 also comprises a fill-up and circulation tool 100 supported underneath the casing running tool. The elastomeric seal 103 is sized for engaging the internal wall of a casing string (not shown in Fig. 10) upon insertion. The seal enables pressurization of the casing string so that pressurized fluid introduced into the bore of the casing string through the bore 101 of the fill-up and circulation tool 100 can be circulated down the casing string and back to the surface through the annulus formed between the casing string and the borehole.

Fig. 11 is a perspective view of another embodiment of the present invention. The single joint manipulator arm 10 of the present invention is secured to and supported by a top drive, and supports a fill-up and circulation tool 100 comprising an elastomeric seal 103. A bore 101 formed by aligned bores in the top drive, sub 88 and the fill-up and circulation tool 100 provides a conduit for introducing fluid into the casing string. The single joint manipulator arm 10 is pivotably secured to an enlarged portion of a sub 88 that is threadably coupled at its inlet 88a (above the sub 88) to a top drive and supports the fill-up and circulation tool 100 from its discharge 88b (below the sub 88). In this embodiment, a pair of bails 14, 114 is suspended from a support ring 89 that is rotatably supported by the top drive.

Fig. 12 is a flowchart describing one embodiment of a high-level method of manipulating casing segment to assemble a casing string. In step 60, the swing arm is rotated to an initial position. A hydraulic cylinder or other actuator is used to rotate the pivot arm away from vertical and to a desired angle according to the orientation of a selected joint in the staging area. In step 62, the hoist is lowered as necessary to position a first elevator, such as a horseshoe elevator, near a proximate end of the targeted casing segment. In step 64, the single joint elevator is coupled to the proximate end of the targeted joint. In step 66, the hoist is raised to begin moving the joint into a suspended position. As the joint is lifted along the ramp to leave the staging area, the swing arm rotates clockwise toward an equilibrium position, and the rotation is dampened in step 68. Once the swing arm and the casing segment are substantially vertical and the joint is suspended in the offset position, the joint is then aligned with the casing segment by powered rotation of swing arm and lowered to abut the casing string in steps 70 and 72. Once the distal end of the joint is in contact with the upper end of the casing string, the joint is threadably coupled to the casing string in step 74. A power tong may be used to rotate the joint to threadedly couple the joint to the casing string. Then, in step 76, the hoist is lowered while the single joint elevator is disengaged from the proximate end of the joint. Lowering the hoist brings the string elevator near the proximate end of the casing string and, in step 78, the string elevator engages the proximate end of that uppermost joint of the casing string. In step 80, the casing string is lifted up slightly. This releases the load on the spider so the spider is released according to step 82. In step 84, with the casing string released by the spider, the hoist is lowered to install the casing string further into the borehole to about the position of the casing string prior to connecting the additional joint in step 74. The spider slips are moved into contact with the casing string to support it in the well. In the step 86, if the string has achieved the desired length, work stops. Otherwise the process repeats as the swing are is rotated to an initial position in step 60.

Embodiments of the invention provide a safe and efficient way to assemble a casing string. A highly maneuverable single joint manipulator arm retrieves a casing joint from a variety of angles to access a staging area. The single joint manipulator arm then positions the casing joint into alignment with the casing string in a controlled manner using a damper. A casing string may also be assembled quickly and efficiently, minimizing the time and expense associated with casing make up.

The terms "comprising," "including," and "having," as used in the claims and specification herein, shall be considered as indicating an open group that may include other elements not specified. The terms "a," "an," and the singular forms of words shall be taken to include the plural form of the same words, such that the terms mean that one or more of something is provided. The term "one" or "single" may be used to indicate that one and only one of something is intended. Similarly, other specific integer values, such as "two," may be used when a specific number of things is intended. The terms "preferably," "preferred," "prefer," "optionally," "may," and similar terms are used to indicate that an item, condition or step being referred to is an optional (not required) feature of the invention.

The terms "segment" and "joint" are used interchangeably to refer to individual portions of casing. The term "casing" is used to refer to casing, production tubing, drill pipe and all other tubulars that may be coupled end-to-end and installed in a well.

While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the claims.