NO20110682L - Method and apparatus for gripping a pipe on a drilling rig. - Google Patents

Abstract

There is disclosed a method and apparatus for carrying out the method, the method comprising: gripping the tube with a gripper; sending an electronic signal to a control unit indicating that the gripper engages the tube; and controlling activation of the gripper by using the control unit to prevent the pipe from being released by malfunction.

Description

METHOD AND APPARATUS FOR GRABING PIPE ON A DRILLING RIG

Embodiments of the present invention generally relate to a gripping assembly for gripping pipes. More specifically, the invention relates to a gripping device for connecting wellbore pipes on a drilling rig. Even more specifically, the invention relates to a gripping device which includes at least one redundant device for keeping gripping elements in contact with the pipe.

During the construction and completion of oil and gas wells, a drilling rig is located on the surface of the earth to facilitate the insertion and removal of pipe strings in and from a well hole. The pipe strings are built and driven into the hole by sinking a string into a wellbore until only the upper end of the pipe protrudes from the wellbore (or above the drill deck). A gripping device, such as a chain belt or a holding ring device, a so-called "spider", at the surface of the wellbore, holds the pipe in place with a bowl-shaped wedge belt while the next pipe to be connected is lifted over the wellbore centre. The next pipe typically has a lower end with a threaded male decoupling, for threaded connection to a female threaded coupling on the pipe string that protrudes from the wellbore. The pipe to be inserted is rotated, using a top-driven machine, in relation to the string until a joint is made between the pipes with a certain torque.

A pipe connection can be made near the deck of the drilling rig using power pliers. Alternatively, a top drive machine facilitates the joining of tubes by rotating the tube from its upper end. The top driven machine is typically connected to the pipe using a pipe gripping tool that grips the pipe. With the pipe connected to a top drive machine, the top drive machine can be used to tighten or break pipe connections, lower a string into the wellbore, or even drill with the string when the string includes an earth removal element at its lower end. One arrangement for connecting a pipe to a top drive machine is described in publication WO 01/79652.

An internal gripper or spear can grip the inside diameter of a pipe to temporarily hold the pipe while a string is built or rotated to drill. An internal gripper is typically connected at an upper end to a top drive machine and at a lower end the internal gripper includes outwardly extending gripper members configured to contact and hold the interior of a tube to transmit axial and torsional loads. The result is a rotationally fixed assembly. However, prior art gripper assemblies are provided with one primary actuator and one mechanical spring retainer to secure the gripper member. Since the fuse is a mechanical fuse, it is susceptible to mechanical failure. Furthermore, because the mechanical fuse is simply a spring, there is no way to remotely monitor its condition.

There is a need for an improved gripper assembly that has additional safety systems to prevent inadvertent disconnection of the string from the gripper. There is a further need for a safety system that utilizes a redundant actuator for the gripper. There is a further need for an integrated safety system between the gripper and a gripper on the drill deck.

Embodiments described herein relate to methods and apparatus for handling pipes on a drilling rig. The apparatus is adapted to grip a pipe and can be used with a top-drive machine.

The apparatus includes a coupling at one end for rotationally attaching the apparatus to the top drive machine and gripping elements at a second end for gripping the tube. The apparatus has a primary actuator configured to move and maintain the gripping members in contact with the tube and a locking assembly for maintaining the gripping member in contact with the tube.

According to a first aspect of the present invention, there is provided a method for handling a pipe, the method comprising: gripping the pipe with a gripping device; sending an electronic signal to a control unit indicating that the gripper is gripping the pipe; and controlling activation of the gripper using the control unit to prevent accidental release of the tube.

According to another aspect of the present invention, there is provided a pipe handling system comprising: a gripping device; and a control unit operable to receive an electronic signal indicating a position of the gripper, wherein the control unit is operable to control activation of the gripper to prevent accidental release of a tube carried by the gripper.

According to a third aspect of the present invention, there is provided a method for operating a pipe handling system, the method comprising: moving a gripping device towards a pipe; detecting the presence of an upper end of the pipe using a sensor located on the gripper; sending a signal from the sensor to a control unit indicating that the pipe is in a position for engagement; stopping movement of the gripper relative to the tube in response to the signal; and to grip the tube with the gripper.

According to a fourth aspect of the present invention, there is provided a pipe handling system comprising: a pipe gripping apparatus having a gripping mechanism; a sensor adapted to track movement of the gripper mechanism, wherein the sensor sends a signal to a control unit when the gripper is in a position consistent with the gripper being engaged with the pipe.

In order that the manner in which the above-presented features of the present invention can be understood in detail, a more detailed description of the invention, which is briefly summarized above, can be obtained by reference to embodiments, some of which are illustrated in the attached drawings. However, it should be noted that the attached drawings only illustrate typical embodiments of this invention and are therefore not to be regarded as limiting its scope, for the invention can accommodate other equally effective embodiments.

Fig. 1 shows a schematic diagram of a drilling rig and a wellbore according to one

execution described herein;

Fig. 2 shows a schematic diagram of a gripping element according to one embodiment which

is described herein;

Fig. 3 shows a schematic diagram of a gripping element according to one embodiment which

is described herein;

Fig. 4 shows a principle diagram of an actuator for a gripping element according to one

execution described herein;

Fig. 5 shows a schematic diagram of a hydraulic actuator according to one embodiment

as described herein;

Figs. 6A-6C show a schematic diagram of a gripping element according to one embodiment which

is described herein;

Fig. 6D shows a sectional view of a swivel according to an alternative embodiment; Fig. 7 shows a schematic diagram of a hydraulic actuator according to one embodiment described herein; Fig. 8A shows a schematic diagram of a hydraulic actuator according to one embodiment described herein; Figs. 8B-8E show a schematic diagram of multiple gripping elements according to one embodiment described herein; Figs. 9A-9B show a schematic diagram of a placement system according to one embodiment described herein; Figs. 10A-10B show a schematic diagram of a sensor according to one embodiment described herein; Figs. 11, 11A-11C show a schematic diagram of an adapter according to one embodiment which

is described herein;

Figs. 12A-12B show a schematic diagram of a cement plug lock according to one embodiment

as described herein;

Fig. 13 shows a schematic view of a trigger mechanism according to one embodiment

as described herein; and

Fig. 14 shows a schematic view of a pipe handling system and a control unit i

according to one embodiment described herein.

Figure 1 is a schematic diagram of a drilling rig 100 having a pipe handling system 102. As shown, the pipe handling system 102 includes a gripper 104, an actuator 106, a drive mechanism 108 and a hoist system 110. The pipe handling system 102 is adapted to grip a pipe 112 or a piece equipment 114 and lift it over the wellbore 115 and then complete a pipe run operation. The actuator 106 for the gripper 104 may be equipped with a backup safety assembly, a locking system and a safety system, which are described in more detail below, to ensure that the tube 112 is not released prematurely. The hoist system 110 and/or the drive mechanism 108 can lower the pipe 112 until the pipe 112 contacts a pipe string 116. The drive mechanism 108 can then be used to rotate the pipe 112 or the piece of equipment 114, depending on the application, to connect the pipe 112 to the pipe string 116 and thereby extend the pipe string 116 After the coupling, a gripper 119 on the drill deck 118, which initially holds the pipe string 116, can release the pipe string 116. The gripper 119, as shown, is a V-belt; however, it should be noted that the gripper 119 may be any gripper on the drill deck 118 including, but not limited to, a retainer ring. With the gripping device 104 gripping the pipe 112 and thereby the pipe string 116, the hoist system 110 and/or the drive mechanism 108 can lower the pipe

112 and the pipe string 116 until the top of the pipe 112 is near the drill deck 118. The gripper 119 is then reactivated to grip the extended pipe string 116 near the drill deck 118 and thereby holds the pipe string 116 in the well. The actuator 106 releases the gripper 104 from the pipe 112. The pipe handling system 102 can then be used to grip the next pipe 112 to be added to the pipe string 116. This process is repeated until the operation is completed. While the pipe string 116 is lowered, the drive mechanism 108 can rotate the pipe string 116. If the pipe string 116 is equipped with a drilling tool 120, shown schematically, rotation of the pipe string 116 can drill out the wellbore as the pipe string 116 is lowered. The pipe 112 can be any pipe or segment including but not limited to casing, extension pipe, production pipe, drill pipe.

Figure 2 shows a schematic view of the pipe handling system 102 according to one embodiment. The pipe handling system 102 includes a swivel 200, a seal 202, in addition to the drive mechanism 108, the actuator 106 and the gripper 104.

The gripping device 104, as shown in Figure 2, is an internal gripping device which is adapted to engage with the inside of the tube 112. The gripping apparatus 104 includes a wedge belt 208, a wedge lock 210 and a mandrel or stem 212 which is coupled to the actuator 106. The wedge belt 208 may be any wedge belt or gripping element adapted to grip the pipe 112 and the wedge belt 208 preferably has barbed grooves (not shown ) to provide interventions. The wedge lock 210 is connected to the mandrel 212 which can be connected to the actuator 106. The actuator 106 moves a sleeve 214, or holds (cage) down to move the V-belt 208 down. When the wedge belt 208 is moved downwards, the angle of the wedge belt and the angle of the wedge lock move the wedge belt radially away from the longitudinal axis of the gripper. This outward radial movement moves the V-belt 208 into engagement with the tube 112. With the V-belt 208 engaged with the tube 112, the weight of the tube 112 will increase the gripping force applied by the V-belt 208 due to the angles of the V-belt 210 and the V-belt 208. Although Figure 2 shows that the sleeve 214 moves downwardly to activate the V-belt 208, any suitable configuration may be used to bring the V-belt 208 into engagement with the tube 112. In another embodiment, the V-belt 208 is activated by moving the V-belt 210 upward relative to to the V-belt 208 and thus forces the V-belt 208 to move radially outward.

In an alternative embodiment, the gripping device 104 can be an external gripper to grip the tube 112 externally. The external gripper can incorporate V-belts which move against the longitudinal axis when activated. Furthermore, a combination of an internal and an external gripper 104 can be used. Even further, the outer gripper may incorporate gripper elements which rotate to engage with the tube. An exemplary external gripper is shown in patent application publication US 2005/0257933.

The actuator 106 is shown schematically in Figures 1 and 2 and may be an electrically powered, mechanically powered or fluid powered assembly designed to release and seat the gripper 104. Further, the actuator 106 may be any combination of electrically powered, mechanically powered or fluid driven actuator.

The swivel 200 allows an electrical source or a fluid source such as a pump (not shown) to transfer a fluid and/or an electric current to the actuator 106 during operation, and in particular during rotation of the actuator 106. The swivel 200 can be a normal swivel such as a SCOTT ROTARY SEAL™ with conventional O-ring type seals. The swivel 200 in Figures 2 and 3 is part of an intermediate piece 215 which has a lower male end 216 and an upper female end 217 for connecting the swivel 200 to other rig components such as, for example, a top-driven machine or the mandrel 212. The upper end of the mandrel 212 can optionally have an adapter 218 to connect the gripper 104 to the swivel 200 or drive mechanism 108. The adapter 218 may simply be a threaded connection as shown or incorporate a locking feature as described in more detail below. The drive mechanism 108 may be any drive mechanism known in the art to carry the pipe 112 such as a top drive machine, a compensator, or a combined compensator and top drive machine or a runner block. The connection between the drive mechanism 108 and the gripper 104 may be similar to the adapter piece 218 and will be discussed in more detail below. The mandrel 212 is configured so that the top drive machine will transmit a rotary motion to the V-belt, as discussed in more detail below.

The actuator 106 may be coupled to the mandrel 212 and operatively coupled to the swivel 200. The swivel 200 may generally be a hollow or solid shaft with grooves or contact rings and an outer ring having fluid ports or brushes. The shaft can rotate freely while the ring is stationary. The fluid is thus distributed from a stationary point to a rotating shaft where the fluid is in turn distributed to various components to operate the equipment that rotates with the mandrel such as the actuator 106 to tighten and release the V-belt 208.

In one embodiment, the actuator 106 is two or more annular piston assemblies 300 as shown in Figure 3. Each annular piston assembly 300 may include a piston 302, a fluid activation chamber 304, a control line(s) 308 (shown schematically), and a fluid inlet 310. Each annular piston assembly 300 is capable of activating the gripper 104 independently of the second piston assembly 300. It is thus built in redundancy to provide a backup safety system. That is, one of the annular piston assemblies 300 is a primary assembly necessary for operation of the actuator 106. The remaining annular piston assemblies 300 are redundant and provide an additional backup safety feature. Each annular piston assembly 300 operates by introducing fluid into the fluid activation chamber 304. The fluid in the activation chamber 304 applies pressure to the upper side of the piston 302. The pressure on the piston 302 moves the piston 302 downwards. The piston 302 is operatively connected to the gripper 104 via the sleeve 214. Although shown coupled to the sleeve 214, it should be understood that any form of activation of the gripper 104 with the pistons 302 is conceivable. To release the gripper 104 from the pipe 112, fluid can be introduced into a release chamber 306. When the fluid pressure in the release chamber 306 acting on the lower side of the piston 302 becomes greater than the fluid pressure above the piston 302, the piston 302 can move upwards and thereby release the gripper 104 from the tube 112. Each of the annular piston assemblies 300 may have the release chamber 306 or none may be equipped with the release chamber. It is conceivable that to release the gripper 104 the pressure in the actuation chambers 304 is simply relieved and the drive mechanism 108 can then be used to release the V-belt 208 as shown in Figure 2 from the tube 112. Although shown with two annular piston assemblies 300, it should be understood that a any number may be used as long as there is at least one primary piston assembly and one redundant or spare piston assembly.

The control lines 308 shown schematically in Figure 3 can be one control line or a series/plurality of control lines for supplying fluid to each individual annular piston assembly 300. The control lines 308 can include a monitoring line for transmitting information back to a control unit 312. The control lines 308 allow an operator or control unit 312 to monitor the conditions in the fluid chambers of each individual piston assembly 300, including but not limited to pressure and temperature. Therefore, if there is a sudden loss of pressure in one of the annular piston assemblies 300, the control unit 312 or the operator can make adjustments to the other annular piston assemblies 300 to ensure that engagement with the tube 112 is not lost. The control conduits 308, although shown as a control conduit, may be any fluid source known in the art such as an annulus surrounding the actuator 106.

In general, the control unit 312 may have additional control lines that operatively communicate with a runner block, a positioning system, a sensor, the drive mechanism, a forceps and/or a pipe handling apparatus. Furthermore, the control unit 312 receives data from the monitoring lines and the drive mechanism. The control unit 312, in various embodiments, can be in fluid, wireless (for example infrared, RF, bluetooth, etc) communication or communication via wire with components of the present invention. For purposes of illustration, the control unit 312 may be communicatively coupled to the drive mechanism, fluid chambers, gripper 104, a trigger, a placement system, one or more sensors, and other drilling rig components. The control unit 312 may generally be configured to operate and monitor each of the respective components in an automated manner (for example according to a programmed sequence stored in memory) or according to explicit user input.

Although not shown, the controller 312 may be equipped with a programmable central processing unit, a memory, a mass storage device, and well-known support circuits such as power supplies, clocks, caches, input/output circuits, and the like. As soon as it is switched on, the operator can control the operation of the gripper 104 by inputting commands into the control unit 312. For this purpose, another embodiment of the control unit 312 includes a control panel not shown. The control panel may include a keyboard, switches, buttons, a touch screen, etc.

With the control unit 312 monitoring and operating the drilling rig, an integrated safety system can be easily adapted to the drilling rig 100. A safety system can prevent a pipe 112 or a pipe string from being lost. In one embodiment, the safety system is adapted to provide an indication of whether the gripper 104 is properly engaged with the pipe 112. Thus, the safety system would let an operator or control unit 312 know that the gripper 104 is fully engaged with the pipe 112. When the gripper 104 engages the pipe 112, which is now part of the pipe string 116, is confirmed by the safety system, the control unit 312 or the operator can release the V-belt or retaining ring at the drill deck. The runner block would then lower the pipe string 116 so that the female end of the pipe is near the drill deck 118. The control unit 312 or the operator can then reactivate the V-belt or retaining ring to grip the pipe string 116. With the V-belt engaged with the pipe string 116, the control unit would allow the gripper 104 to release the pipe string 116 .The safety system is also capable of monitoring the proper amount of tightening torque in the pipe's 112 threads when tightening. This ensures that the threads are not damaged during tightening and that the connection is secure. Examples of suitable security systems are illustrated in US 6,742,596 and patent applications US 2005/0096846, 2004/0173358 and 2004/0144547.

In an alternative embodiment, the gripper 104's actuator 106 includes one or more piston and cylinder assemblies 400 as shown in Figure 4. The piston and cylinder assemblies 400 are connected to the mandrel 212 via a collar 402 and are movably connected to the sleeve 214 via a drag ring 404. 404 is coupled to a rod 406 in each of the piston and cylinder assemblies 400. The slip ring 404 is operatively coupled to the sleeve 214 to actuate the gripper 104. It should be understood that any method known in the art for securing the piston and cylinder assemblies 400 until mandrel 212 and sleeve 214 can be used. Any one of the piston and cylinder assemblies 400 is capable of moving the slip ring 404 to actuate the gripper 104, and therefore all but one of the piston and cylinder assemblies 400 are redundant or provide backup, and one of the pistons is the primary actuator. It should further be understood that other power sources besides fluid sources can also be used to provide power to the gripper 104 either separately or in conjunction with fluid power. These alternative power sources include, but are not limited to, electricity, batteries, and stored energy systems such as power springs and compressed gas.

In another embodiment, the actuator can be driven electrically. The electrically powered actuator may be equipped with a mechanical locking device that acts as a backup assembly that prevents release of the gripper 104. Furthermore, the electrically powered actuator may include more than one actuation element for redundancy or as a backup. Even further, the electrically powered actuator can send data to a control unit 312 to communicate its position to an operator. Thus, if one lock fails, the control unit 312 can take steps to prevent accidental release of the tube 112.

As described above, a separately operable redundant actuator, to provide for redundancy or safety assembly, may be used to ensure operation of the gripper 104 in the event of failure of the primary actuator. In one embodiment, the actuator 106, as shown in Figure 3, includes four piston assemblies 300. The primary actuator may be one of the piston assemblies 300, while any or all of the remaining piston assemblies 300 may act as the redundant actuator. The redundant actuator works in the same way as the primary actuator. That is, the redundant actuator applies an activation force to the gripper 104 when the fluid is supplied to the redundant actuator's activation chamber 304. As discussed above, the fluid pressure in the activation chamber 304 can be monitored by the control unit 312. The redundant actuator will provide the activation force to the gripper 104 even in the event that a primary actuator fails. Furthermore, further actuators, which are operated in the same or similar manner as the redundant actuator, can be provided.

In another embodiment, one or more valves 314, which are shown schematically in Figure 3, are arranged between the control line(s) 308 and the activation chamber 304 to provide the additional and/or alternative backup safety assembly. The valve 314 allows fluid to enter the activation chamber 304, but does not allow fluid to exit the activation chamber 304. The valves 314 can be set so that they release the pressure when the release chambers 306 are activated. The valve 314 is typically a one-way valve such as a check valve, however, it should be understood that any valve may be used, including but not limited to a cargo valve. In operation, the fluid enters the activation chamber 304 and activates the annular piston assembly 300, thereby engaging the gripper 104 V-belt 208 with the tube 112. The fluid also acts as redundancy to prevent the gripper 104 V-belt 208 from releasing from the tube 112 before pressure is applied to the opposite end of the piston 302. In this embodiment, the valve 314 acts so that it maintains a substantially constant pressure on the piston 302, even if the fluid pressure in the control line(s) is accidentally lost or selectively turned off. This in turn maintains a constant locking force on the V-belt 208. The valves 314 can be built into the actuator 106 or added and/or soldered in as an addition to the actuator 106. Furthermore, the valve 314 can be located anywhere between the fluid source for operation of the annular piston 300 and the actuation chamber 304. The valve 314 can be attached to each actuation chamber 304 or to any number of fluid chambers depending on the actuator 106 requirements. Thus, only one of the activation chambers 304 is necessary, during operation, for the V-belt 208 to engage. The additional activation chambers 304 may be equipped with the valve 314 as a safety chamber which, once activated, prevents the gripper 104 from accidentally releasing the tube 112. The valves 314 will operate on the basis of a single piston. Thus, if multiple pistons are used and if one piston is lost or leaks pressure due to a failed seal, the redundant actuator will continue to maintain the application force on the V-belt 208.

In yet another alternative embodiment, the redundant actuator is one or more of the piston and cylinder assemblies 400, and the primary actuator is one of the piston and cylinder assemblies 400, as shown in Figure 4. As described above, the primary actuator and each of the redundant actuators capable of independently operating the gripper 104. Further, as shown in Figure 3, the control unit 312 is capable of monitoring the conditions of the primary actuator and the redundant actuators to ensure that the gripper 104 remains engaged with the tube 112 when it is desired.

In yet another embodiment, at least some of the piston and cylinder assemblies 400 are provided with a valve 500, shown schematically in Figure 5, to provide a backup assembly as an additional safety feature to prevent inadvertent release of the gripper 104. As shown each of the piston and cylinder assemblies 400 includes a cylinder 502 and a piston 504. There may be two fluid control lines connected to each of the piston and cylinder assemblies 400. An actuator line 506 is connected to each cylinder 502. The actuator line 506 applies hydraulic or pneumatic pressure to each piston 504 to actuate the gripper 104 (shown in Figures 1-4). A release line 512 is connected to each of the cylinders 502 below the piston 504 to release the gripper 104. One or more feed lines 508 may be connected to each of the actuation lines 506. Additional separate feed lines may be used to provide power to each of the pistons. and the cylinder assemblies 400 separately. Each of the activation conduits 506 may be provided with the valve 500, but although each of the activation conduits 506 is shown as having the valve 500, it should be understood that as few as one valve 500 may be used.

To activate the gripper 104, fluid flows through the one or more feed lines 508. The fluid enters each of the activation lines 506 and then flows past the valves 500. The valves 500 operate in a manner that allows fluid to flow toward the cylinder 502, but not back. toward the feed line 508. As the fluid continues to flow past the valves 500, it fills up each of the lines downstream of the valves 500. The fluid can then begin to exert a force on the pistons 504. The force on the pistons 504 causes the pistons 504 to move the slip ring 404 (shown in figure 4) and activates the gripping device 104. The wedge belt 208 will then engage with the pipe 112. With the wedge belt in full engagement, the fluid will no longer move the pistons 504 downwards. Introduction of fluid can be stopped at a predetermined pressure which can be monitored by the control unit 312 or an operator. The only force on the pistons 504 in the activated position is the fluid pressure above the pistons 504. The system will remain in this state until the pressure is released by switches 510 or valves 500 or in the event of a system failure. Each of the valves 500 acts as a safety system to ensure that the gripper does not accidentally release the pipe 112. In operation, the V-belt 208 can be released by activating the switches 510 and allowing the fluid to leave the top of the pistons 504. Fluid is then introduced into the release lines 512 to push up underside of pistons 504. With the fluid released from the top of pistons 504, no additional force is required to release V-belt 208 other than friction between V-belt 208 and tube 112. Although valves 500 are shown in conjunction with piston and cylinder assemblies 400, it should be understood that the valves 500 and hydraulic system may be used in conjunction with any actuator disclosed herein.

In yet another alternative embodiment, one or all of the piston and cylinder assemblies 400 may be equipped with an optional accumulator 514, as shown in Figure 5. The accumulator 514 provides an additional safety feature to ensure that the gripper 104 does not prematurely release the tube 112. The accumulator 514 is located, as shown, between the valve 500 and the cylinder 502 within each of the activation lines 506. An accumulator line 516 fluidly connects the accumulator 514 to the activation lines 506. Each accumulator may include an internal bladder or membrane (not shown). The bladder is an impermeable elastic membrane that separates the piston and cylinder assembly 400 system fluid from the compressible fluid in the accumulator 514. Before the piston and cylinder assembly 400 system fluid is operated, the accumulator 514 is filled with compressible fluid to a predetermined pressure. With only the compressible fluid in the accumulator 514, the bladder will expand to cover the lower end of the accumulator 514 against the accumulator line 516. With the bladder in that position, the accumulator bladder has reached its maximum expansion. As the fluid to operate the piston and cylinder assemblies 400 enters the accumulators 514, the diaphragm of the bladder begins to move upward relative to the accumulator conduits 516. The bladder further compresses the compressible fluid as the bladder moves upward into the accumulators 516. When the V-belt is in full engagement , the fluid will no longer move the pistons 504 downwards. The system fluid will continue to cause the bladder to contract while compressing the compressible fluid in the accumulators 514. System fluid introduction will be stopped at a predetermined pressure. As discussed above, the system may remain in this state until the pressure is released by switches 510 or in the event of a system failure.

In the event that the hydraulic system leaks, the system will slowly begin to lose its system fluid. However, the compressible fluid in the accumulators 514 will maintain the pressure in the system fluid by adding volume when the system fluid is lost. As the compressible fluid expands, the bladder expands and thus maintains the pressure in the system fluid by adding volume to the system. The expansion of the bladder is proportional to the amount of systemic fluid that is lost. In other words, the pressure in the system fluid and in turn the pressure on the piston 504 remains constant when system fluid is lost, due to the expansion of the bladder. The bladder continues to move as systemic fluid leaks out until the bladder is fully expanded. Once the bladder is fully expanded, any further leakage of the system fluid will cause a loss of pressure in the system. The pressure in the accumulators 514 can be monitored by the control unit 312. Thus, upon loss of pressure in the accumulators 514, the control unit or an operator can increase the pressure in the piston and cylinder assemblies 400 and thereby prevent the gripper 104 from being released by accident. Each of the valves 500 and accumulators 514 act independently for each of the piston and cylinder assemblies 400. Therefore, there can be one primary piston having a valve 500 and an accumulator 512 and any number of redundant pistons having a valve 500 and an accumulator 514 which thereby provides an increased safety factor. The accumulators 514 may be used with any actuator described herein.

In an alternative embodiment to the swivel 200 discussed above, a swivel 600 is connected directly to the actuator 106, as shown in Figure 6A. This reduces the overall length of the gripper 104 in that the intermediate piece 215 is not required. The swivel 600 has a fluid nozzle 602 which is attached to a control line 604 which is connected to a fluid source or an electrical source 606 (shown schematically). The swivel 600 additionally has a fluid chamber 180 which communicates with the actuator 106 via a port 608 to release or engage with the V-belt

208. The swivel 600 contains a housing 610 which may comprise the fluid nozzle 602, two or more sealing rings 612 and a base unit 614 which is directly connected to the rotating element. Furthermore, the swivel 600 includes slip rings 616 that couple the housing 610 to the base assembly 614 while allowing the housing 610 to remain stationary while the base assembly 614 rotates. Figure 6B shows the swivel 600 coupled to an actuator 106A according to an alternative embodiment. Figure 6C shows two swivels 600 attached to an actuator 106B. Actuator 106B has a piston 618 which moves upward by fluid supplied from the lower swivel 600 and moves downward by fluid supplied from the upper swivel 600. The piston 618 operates the gripper 104. It should be understood that the swivels 600 may be used with any actuator device 106 disclosed herein or known in the art. Furthermore, any number of swivels can be used.

In yet another alternative embodiment, the redundancy for any of the actuators described above can be achieved by means of a primary fluid system with an electrically powered reserve. Furthermore, the primary system can be electrically operated and the redundant system can be fluid operated.

In yet another alternative embodiment, the above-described swivel 200 and/or 600 can take the form of a rotary coupling 620, as shown in Figure 6D. The rotary coupling

620 includes an inner rotatable member 622 and an outer stationary member 624. The inner rotatable member 622 may be coupled to the pipe handling system 102 rotating components, such as the drive mechanism 108 and the actuator 106. The outer stationary member 624 is adapted to be coupled to one or several steering wires to

operate the pipe handling system's 102 components. As shown, the rotary coupling 620 includes two inlets 626 for hydraulic fluid and four inlets 628 for pneumatic fluid. However, it should be noted that any combination of pneumatic fluid, hydraulic fluid, electrical, and fiber optic inlets may be used including only one hydraulic fluid inlet 626 and/or one pneumatic fluid inlet 628. The inlets 626 and 628

may optionally include a valve for controlling flow. A bearing 630 may be included between the inner rotatable element 622 and the outer stationary element 624 for storage of radial and axial forces between the two elements. As shown, the bearing 630 is located at each end of the outer stationary member 624.

The hydraulic fluid inlet 626 is connected to an annular chamber 632 via a port 634 through the outer stationary element 624. The annular chamber 632 encloses the entire inner diameter of the outer stationary element 624. The annular chamber 632 is fluidically connected to a control port 636 which is located inside the inner rotatable element 622. The control port 636 can be fluidically connected to any components of the pipe handling system 102. For example, the control port 636 can be connected to the actuator 106 to operate the primary actuator and/or the redundant actuator.

To prevent leakage between the inner rotatable member 622 and the outer stationary member 624, a hydrodynamic seal 638 may be provided at a location in a recess 640 on each side of the annular chamber 632. As shown, the hydrodynamic seal 638 is a high speed lubrication fine) which is adapted to seal the increased pressure needed for the hydraulic fluid. The hydrodynamic seal 638 may be made of any material including, but not limited to, rubber, a polymer, an elastomer. The hydrodynamic seal 638 has an irregular shape and/or location in the recess 640. The irregular shape and/or location of the hydrodynamic seal 638 in the recess 640 is adapted to create a cavity 641 or space between the walls of the recess 640 and the hydrodynamic seal 638. In operation, the hydraulic fluid enters the annular chamber 632 and continues into the cavities 641 between the hydrodynamic seal 638 and the recess 640. The hydraulic fluid moves in the cavities when the inner rotatable element 622 is rotated. This movement circulates the hydraulic fluid within the cavities 641 and drives the hydraulic fluid between the contact surfaces of the hydrodynamic seal. The circulation and operation of the hydraulic fluid creates a layer of hydraulic fluid between the surfaces of the hydrodynamic seal 638, the recess 640 and the inner rotatable element 622. The hydraulic fluid layer lubricates the hydrodynamic seal 638 to reduce heat generation and extend the life of the hydrodynamic seal. In an alternative embodiment, the hydrodynamic seal 638 is narrower than the recess 640 while having a height substantially equal to or greater than the recess 640. The hydrodynamic seal 638 may also be circumferentially longer than the recess. This configuration forces the hydrodynamic seal 638 to flex in the recess as shown as a wavy hidden line in Figure 6D. When rotated, the hydraulic fluid circulates in the cavities 641 as described above. Each of the inlets may include the hydrodynamic seal 638. Each of the inlets may have the control port 636 for operating separate tools in any of the components of the pipe handling system 102.

A seal 642 may be located between the inner rotatable member 622 and the outer stationary member 624 at a location in a recess 640 on either side of the annular chamber 632 of the pneumatic fluid inlets 628. The seal 642 may include a standard seal 644 on one side of the recess and a low friction pad 646. The low friction pad may comprise a low friction polymer including, but not limited to, Teflon™ and PEEK™. The low friction pad 646 reduces friction on the standard seal 644 during rotation. Any of the seals described herein may be used for any of the inlets 626 and/or 628.

The pipe handling system 102 may include a compensator 700, as shown in Figure 7. The compensator 700 compensates for the length loss due to the thread tightening without having to lower the drive mechanism 108 and/or the top drive machine during the connection of the pipe 112 to the pipe string 116. This system does not only length compensation when the threads are tightened, it also controls the amount of weight placed on the threads being tightened so that the threads are not subjected to too much weight during tightening. The compensator 700 consists, as shown, of one or more compensating pistons 702 which are connected at one end to a fixed location 704. The fixed location 704 can be connected to any part of the pipe handling system 102 which is longitudinally fixed in relation to the pipes 112. The fixed location 704 is, as shown, coupled to the top driven machine. The other end of the compensating pistons 702 is operatively connected to the piston and cylinder assemblies 400 via a coupling ring 708. The piston and cylinder assemblies 400 are connected to the gripper 104 as described above. The compensating pistons 702 are adapted to remain stationary until a preset load is reached. When the load is reached, the compensator pistons 702 will allow the coupling ring 706 to move with

the load thereby allowing the gripper 104 to move.

In operation, the gripper 104 grips the tube 112. With only the tube 112 connected to the gripper, the compensator piston 702 will remain in its initial position. The pipe 112 will then engage the pipe string 116, shown in Figure 1. The drive mechanism 108 will then rotate the pipe 112 to connect the pipe 112 to the pipe string 116. As the threaded connection is tightened, an additional load is applied to the gripper 104 and thereby to the compensating pistons 702. The compensating pistons 702 will move in response to the additional load thereby allowing the gripper to move longitudinally downward as the thread connection is completed. Although the compensator 700 is shown with the piston and cylinder assemblies 400, it should be understood that the compensator 700 can be used in conjunction with any actuator described herein.

The compensator pistons 702 can be controlled and monitored by the control unit 312 via a control line(s) 708. Control line(s) 708 enable the pressure in the compensating pistons 702 to be controlled and monitored according to the operation being carried out. The controller 312 is able to adjust the sensitivity of the compensator pistons 702 to enable the compensator pistons to move in response to different loads.

In another embodiment, the compensator 700 is simply a splined sleeve or collar, not shown. The keyway sleeve allows longitudinal release or movement between the drive mechanism 108 and the gripper 104. In yet another embodiment, the compensator may include a combination of pistons and the keyway sleeve.

The actuator 106 can be adapted for variable and/or modular use, as shown in Figures 8A-8E. That is, one actuator 106 can be adapted to operate any size or variation of a modular gripper 804. Figure 8A shows that the actuator 106 has the piston and cylinder assemblies 400, one or more compensator pistons 702 and an adapter 218 to connect the actuator 106 to the drive mechanism 108 (shown in figure 1). The adapter 218 may include a torque spacer to monitor torque applied to the pipe 112. Figures 8B-8E show various exemplary modular grippers 804 that may be used with the actuator 106. Activation of the selected gripper 804 is accomplished using a modular slip ring 802. The modular slip ring 802, which is similar to slip ring 404 described above, connects to piston and cylinder assemblies 400 and can be moved with them, as described above. The modular drag ring 802 is adapted to be coupled to an attachment drag ring 806 in the modular gripper 804. When coupled to the attachment drag ring 806, the drag ring 802 can activate the gripper 104 as described above. In this regard, slip rings 802 and 806 move in unison in response to actuation of the piston and cylinder assemblies 400 which in turn causes the gripper to engage with or disengage from the tube 112. Torque from the drive mechanism 108 can be transmitted to the modular gripper 804 by using a universal joint 808. As shown, the universal joint 808 is located at the end of a rotatable shaft 810 in each modular gripper 804. The universal joint 808 is adapted to connect to a shaft inside the actuator 106. With the universal joint 808 connected to the actuator 106 shaft, rotation can is transferred from the drive mechanism 108 to the rotation shaft 810 and in turn to the pipe via the modular gripper 804.

In operation, the modular construction of the pipe handling system 102 allows quick and easy fitting of any size pipe 112 without the need to remove the actuator 106 and/or the drive mechanism 108. Thus, the external modular gripper 804, which is shown in Figure 8B, can be used for basically to grab, connect and drill with the pipe. The external modular gripper 804 can then be removed by disconnecting the drag ring 806 from the drag ring 802. The internal gripper 804, which is shown in Figure 8E, can then be used to continue connecting, driving and drilling with pipe 112. It is expected that gripper of any suitable size may be used in operation. Furthermore, any of the actuators 106 described herein may be used in conjunction with the modular gripper 804.

Figures 9A and 9B show a positioning system 900 that can be used with any gripper assembly and any of the actuators 106 disclosed herein. The position system 900 can be incorporated into the actuator 106 which has the piston and cylinder assembly 400, as shown. The positioning system 900 is adapted to track the movement of the slip ring 404 or the piston rod 406 as it is moved by the piston and cylinder assemblies 400. The positioning system 900 may be in communication with the control unit 312 to monitor the engagement and release of the gripper 104. The positioning system 900 tracks the position of pistons and thus the position of the gripper 104 is tracked. The positioning system 900 may include a wheel 902 which is connected to an arm 904 which is connected to the piston rod 406, or in the alternative, to the sleeve 214 or the slip ring 404. When the piston rod 406 moves the slip ring 404 from the released position to the engaged position, the wheels roll on a track 906. The track 906 may include a raised portion 907. As the wheel 902 reaches the raised portion 907, it moves the arm 904 radially away from the gripper 104 mandrel 212. The arm 904 is engaged to a trigger 908 which activates a position indicator 910. Thus, when the trigger 908 engages with the position indicator 910, the height and position of the trigger 908 within the position indicator 910 indicates the position of the piston rods 406 and or the slip ring 404 and thus the position of the V-belt 208, not shown. Although groove 906 is shown with one raised portion, it should be understood that groove 906 may have any configuration and indicate the full range of positions where piston rod 406 and/or slip ring 404 may be during activation and release of the gripper. The position system 900 can send and/or receive a pneumatic and/or a hydraulic signal to the control unit 312 and/or the fluid source and can further send an electronic signal, either wirelessly or by means of a wired communication line. Furthermore, the position system 900 can be any position sensor including, but not limited to, a Hall effect sensor, a strain gauge, or any other distance sensor. The sensor's communication signal can be sent back through the swivel and/or sent via radio frequency.

In yet another embodiment, the gripper 104 includes a sensor 1000 for indicating that a stop collar 1002 in the gripper 104 has reached the top of a pipe 112, as shown in Figures 10A and 10B. The stop collar is adapted to prevent the pipe 112 from moving past the gripper 104 when the gripper 104 engages the pipe 112. The sensor 1000 can detect the pipe 112 when the pipe 112 is close to the stop collar 1002. In use, the hoist system 110 and/or the drive mechanism 108 will initially lower the gripping device 104 against the tube 112 to press the engaging part of the gripping device to enter the tube 112, or encircle the tube 112 if the gripping device is an external gripping device. As the hoist system 110 and/or the drive mechanism 108 continues to move the gripper 104 relative to the pipe 112, the sensor 1000 will be activated when the pipe 112 reaches a predetermined distance from the stop collar 1002. The sensor 1000 may send a signal to the control unit 312 or an operator to indicate that the stop collar 1002's predetermined proximity to the pipe 112 is reached. The control unit 312 and/or the operator can then stop the hoist system 110 and/or the drive mechanism 108 from further movement of the gripping device 104 in relation to the pipe 112. The gripping device can then be activated to grip the pipe 112 to start drilling and/or driving operations.

The sensor 1000, as shown in figures 10A and 10B, is a mechanical sensor which rests in a recess 1004 in the stop collar 1002 and is influenced to protrude below the bottom surface of the stop collar 1002. Figure 10 B shows the sensor 1000 connected to an activator 1006 which operates a control valve 1008. The activator 1006 is, as shown, a rod that projects through the stop collar 1002 and is connected to the control valve 1008 at one end and to a contact 1010, which is adapted for to engage with the pipe 112, at the other end. The sensor 1000 may include a spring 1007 to bias the actuator 1006 towards the free position. Thus, the contact 1010 approaches the upper end of the pipe 112 when the gripper is lowered into the pipe 112. As soon as the contact 1010 engages with the pipe 112, the control valve 1008 is activated and sends a signal to the control unit 312 or the operator indicating that the gripper 104 is inside in tube 112. Although sensor 1000 is shown as a mechanical sensor, it should be understood that sensor 1000 may be any sensor known in the art, such as a piston-and-rod assembly, a tension flap, one of -position sensor, an optical sensor, infrared, a laser sensor. The sensor 1000 helps prevent the full weight of the hoist system 110, actuator 106, and drive mechanism 108 from being placed on top of the pipe 112 before the pipe 112 is connected to the pipe string 116. In one embodiment, the status of the sensor 1000 can be sent back through the swivel and/or transmitted via radio -quence.

In yet another embodiment, the adapter 218, which can provide a connection between the components of the pipe handling system 102, includes a latch 1100 as shown in Figure 11. The adapter 218 is located between the drive mechanism 108 and the actuator 106, however, it should be understood that the adapter 218 can be placed between any of the pipe handling system 102 components. The lock 1100 prevents the erroneous release of a connection between components of the pipe handling system 102 as a result of rotation of the components. As shown, the connection includes a male coupling 1102 in the drive mechanism 108 which is adapted to couple to the female end 1103 of the actuator 106. Both the male coupling 1102 and the female end 1103 have a shaped outer surface 1104. The shaped outer surface 1104 shown in Figure 11A is an octagonal configuration, however, it should be understood that the shape can be any configuration capable of transmitting torque, such as a gear or knurled, a hexagon, a square, a keyway, etc. The shaped outer surface 1104 is configured to fit with a shaped inner surface 1106 in the latch 1100. The latch 1100 may include a locking screw 1108 to connect the latch 1100 to the male connector 1102. Although the locking screw 1108 is shown connected to the male connector 1102, it should be understood that the locking screw 1108 can be connected to any part of the connection as long as the lock 1100 engages with both the male connector 1102 and the female end 1103. Thus, the lock 1100 is placed, in operation, on the male connector a 1102 and the female end 1103 are connected to the male connector 1102. The lock 1100 is then moved so that the shaped inner surface 1106 engages with the shaped outer surface 1104 on both the male connector 1102 and the female end 1103. The locking screws 1108 then connect the lock 1100 to the male connector 1102. The drive mechanism 108 can then activated to rotate the pipe 112. As the drive mechanism pulls the coupling, load is transferred through the lock 1100 in addition to the threaded connection. The lock 1100 prevents overloading or tearing of the threads (unthreading) of the connections. Although the drive mechanism 108 is shown with a male end and the actuator 106 with a female end, any configuration may be used to ensure connection. Further, the latch may include a sprag clutch to engage with a top drive machine hollow shaft, eliminating the requirement to modify the top drive machine hollow shaft diameter, not shown.

In yet another embodiment, the adapter 218 is an external locking tool 1110 as shown in Figures 11C and 11B. The external locking tool 1110 may include two or more link members 1112 that are connected to enclose the connection between the components of the pipe handling system 102. As shown, the link members 1112 are rotatably connected to each other via a bolt 1114. The bolts 1114 can be removed to open the external locking tool 1110 and place the external locking tool 1110 around the connection. The bolt 1114 can then be reinstalled to lock the external locking tool 1110 around the connection. Furthermore, any number of link elements 1112 can be removed or added to adjust the size of the connection. The link elements 1112 form, when connected, an inner diameter having two or more slopes 1116. Each link element 1112 may have one or more recesses 1117 to accommodate the slope 1116. The inner diameter is adapted to be equal to or greater than the outer diameter of the connection between the pipe handling system 102 components, the trays 1116 have an engagement surface adapted to engage with the outer diameter of the connection between the pipe handling system 102 components. In one embodiment, the slopes are large enough to cross the connection between the pipe handling system's 102 components. Optionally, the slopes 1116 can be radially adjustable via one or more adjustment screws 1120. As shown, the adjustment screw 1120 crosses each of the link elements 1112. The adjustment screw 1120 engages with the slope 1116 on the inside of the link element 1112 and is accessible on the outside of the link element 1112. Although the adjustment screw 1120 is shown as a screw, it should be understood that any means of radially moving the trays may be used, including but not limited to a fluid actuated piston, an electric actuator, or a bolt. In this way, the link elements 1112 with the slopes 1116 can be connected together around a connection between two components. The lugs 1116 can then be adjusted, if necessary, via the adjustment screws 1120 to engage with the connection. Each hill 1116 will span the (transverse) connection and thereby engage both components. The feet 1116, which are connected to the link elements 1112 will prevent the components from rotating in relation to each other, thereby preventing the release of the coupling by accident.

Figure 11B shows an alternative embodiment of the external locking tool 1110. As shown, each link element 1112 has at least two separate lugs 1116. The lugs are individually adjustable via the adjustment screw 1120. This allows each lug 1116 to independently engage with each connecting component. Therefore, the components can have varying outer diameters and still be gripped by the separate jaws 1116 in the external locking tool 1110. With the jaws 1116 in fixed engagement with the components, relative rotation between the components is prevented in the same way as described above.

In another embodiment, equipment 114 is a cement plug sluice 1200 adapted for use with the gripper 104 as shown in Figures 12A-12B. The cement plug sluice 1200 can be adapted to be gripped by any pipe handling system 102 described herein in addition to any pipe travel device in a drilling rig. For example, the cement plug sluice can be adapted to interface with an internal gripper, an external gripper, or any combination of an external and/or internal gripper. Use of the cement plug sluice 1200 in conjunction with the gripper 104 allows an operator to use a cementing tool without the need to rig down the gripper 104 prior to use. This saves rig time and reduces exposure of the pipe string 116 to the uncemented wellbore. Furthermore, the cement plug sluice 1200 can be brought to the drill deck as a complete assembly that can be handled and connected to the pipe string 116 with the grabber. This allows rapid operation while protecting the plugs inside the casing and the equipment 114. Furthermore, only the cement plug sluice 1200 needs to be attached to the pipe handling system 102 when the cementing operation is to take place. The cement plug sluice 1200 can allow the pipe string 116 to be cemented in place without the need to pump cement through the gripper 104, the actuator 106 and the drive mechanism 108.

The cement plug sluice 1200 will be described as used with an internal gripping device 104. As shown in Figure 12A, the sluice 1200 has an upper pipe length 1202 and an optional sluice swivel 1204, a fluid inlet 1205 and a valve 1206. The swivel 1204 may function in the same manner as the swivels mentioned above. The valve 1206 is shown as a check valve, however, it may be any type of valve including but not limited to a ball valve, a gate valve, a one-way valve, a relief valve, and a so-called TIW valve. The valve 1206 is adapted to prevent cement and/or drilling fluids from flowing through the cement plug sluice 1200 during a cementing operation. Furthermore, the valve 1206 can prevent the pump pressure from affecting the gripping device 104's load capacity during circulation or cementation. The upper pipe length 1202 of the cement plug sluice 1200 is adapted to be gripped by the gripping device 104. Thus, after the pipe string 116 has been driven and/or drilled and/or reamed to the desired depth, the gripping device 104 can release the pipe string 116 and pick up the sluice 1200. To grip sluice 1200, the gripping device 104 is introduced into the upper pipe length 1202. The actuator 106 then activates the V-belt 208 to engage with the upper pipe length 1202. The gripping device 104 and the cement plug sluice 1200 are then lifted by the hoisting system over the pipe string 116. The hoisting system can then lower the cement plug sluice 1200 towards the pipe string 116 for engagement with it. The drive mechanism 108 can then rotate the cement plug sluice 1200 to connect the cement plug sluice 1200 to the pipe string 116. Thus, a cementing operation can be performed with little or no modification to the pipe handling system 102. In one embodiment, the pipe handling system 102 can have the sealing feature that allows fluid to be pumped into the cement plug sluice. 1200 internal diameter above valve 1206.

The cement plug sluice 1200 shown in Figure 12A shows a typical sluice head as described in US 5,787,979 and 5,813,457, and the additional features of the sluice swivel 1204 and the upper pipe length 1202 adapted to be gripped by the gripper 104. The sluice 1200(a) shown in Figure 12B shows the use of a plug sender system as a user

conventional plugs as well as non-rotating plugs as described in US 5,390,736. The sluice 1200(a) further includes a sluice swivel 1204 which allows fluid to be pumped into the well while the valve 1206 prevents fluid from flowing to the grabber 104. The fluid can be any fluid known in the art such as cement, production fluid, separation fluid (spacer fluid), mud, fluid to convert mud to cement, etc. Plug sluice assembly 1200 and 1200A may allow the tubing string 116 to be rotated during the cementing operation. Figure 12C shows the cement plug sluice 1200(b) which is adapted for remote control and which will be described below.

It should be understood that the cement plug locks 1200 and 1200A can be used in conjunction with clamps, casing claws, or even another gripping device such as a spear or external gripping device to connect with the previously run tubing string 116.

The cement plug locks 1200 and 1200A are shown with manual plug releases. In yet another alternative embodiment, the cement plug locks 1200 and 1200A are equipped with a remote-operated activation system. In this embodiment, the manual plug releases are replaced by or equipped with plug activators. The plug activators are controlled fluidically, electrically or wirelessly from the control unit 312. Therefore, the control unit or an operator at a remote location can trigger each plug 1208 and 1210 at the desired time using the plug activators. The plug activators typically remove an element that prevents the plugs 1208/1210 from traveling down the cement plug sluice 1200/1200(a) and into the pipe 112. Thus, the plug 1208/1210 performs the cementing operation, with the element removed after activation of the plug activator. The fluid line or electrical line used to operate the plug actuators may include a swivel to communicate with the plug actuators during rotation of the cement plug sluices 1200 and 1200(A). Alternatively, the plug activators may release a ball or release plug (dart) adapted for use with plugs 1208 and 1210.

During a cementing operation, it may be advantageous to move the pipe string 116 back and forth and/or to rotate the pipe string 116 when the cement enters the annulus between the wellbore 115 and the pipe string 116. The movement, back and forth and/or rotating, can be performed using the hoist system 110 and the drive mechanism 108 and helps to ensure that the cement is distributed in the annulus. The remote actuation system for the cement plug sluice can be useful during the movement of the pipe string 116 to prevent the operators from being injured while releasing the plugs 1208 and 1210, due to the movement of the cement plug sluice.

Although the cement plug sluice may be used or referred to in connection with the redundant safety mechanism for a gripping device, it will be understood that the sluice need not be associated with any other aspect or subject matter included herein.

In a further embodiment, the pipe handling system 102 may include a trigger 1300 as shown in Figure 13. During operation of the pipe handling system with an internal wedge-type gripper, it is possible that the wedge belt 208, which is shown in Figure 2, may become stuck in the pipe 112. This can happen when the gripping device 104's V-belt 208 engages with the tube 112 accidentally in a position where the gripping device is unable to move in relation to the tube 112. The gripping device's 104 stop collar 1002 hits, for example, the top of the tube 112 and the V-belt 208 engages with the pipe 112. Now the V-belt 208 further engages with the pipe 112 if the gripping device 104 is pulled up in relation to the pipe 112, and further downward movement in relation to the pipe 112, to release the V-belt 208, is prevented due to the stop collar 1002 and the top of the tube 112 are in contact with each other. The trigger 1300 is adapted to selectively release the gripping device 104 from the tube 112 in the event that the gripping device is stuck and may be incorporated into the stop collar 1002 or it may be a separate unit. The trigger 1300 may have a trigger piston 1302 and a trigger chamber 1304. The trigger chamber 1304 may be coupled to fluid resistance 1306, such as a LEE AXIAL VISCO JET™ and a valve 1307. The valve 1307 shown is a one-way valve or a check valve. The fluid resistance 1306 prevents fluid pressure in the trigger chamber 1304 from activating the trigger piston 1302 quickly. The valve 1307 prevents fluid from flowing from the trigger chamber towards the trigger piston but allows fluid to flow in the opposite direction. The release 1300 may further include an impact element 1308 which is adapted to influence the release piston 1302 towards the released position as shown in Figure 13. The release 1300 operates when the stop collar 1002 engages with the tube 112 and weight is placed on the mandrel 212 of the gripper 104 by means of the hoist system, shown in figure 1. The mandrel 212 can be coupled to the release piston 1302 by means of a coupling device 1309. A downward force applied to the mandrel 212 compresses the fluid in the release chamber 1304. The initial compression will not move the release piston 1302 due to the fluid resistance 1306. Continued compression of the fluid chamber 1304 slowly flows fluid through the fluid resistance 1306 and acts on the release piston 1302. When the release piston 1302 activates a piston cylinder 1310, the piston cylinder 1310 moves the mandrel 212 upwards relative to the stop collar 1002. Thus, the mandrel 212 slowly releases the V-belt 208 from the tube 112 with continued compression of the release chamber 1304 Further h internal fluid resistance 1306 accidental release of V-belt 208 caused by sudden loading on mandrel 212. Continued actuation of trigger chamber 1304 to maximum piston stroke will release V-belt 208. Gripper 104 can then be removed from the tube. When weight is removed from the stop collar 1002, the pressure in the release chamber drops rapidly. Actuator 1308 pushes the piston back toward the released position and valve 1307 allows fluid to return to the trigger chamber. In another embodiment, the trigger 1300 is provided with an optional shoulder 1312. The shoulder 1312 is adapted to rest on top of the tube 112.

Figure 14 is a schematic view of an integrated security system 1400 and/or a lock. The integrated safety system 1400 can be adapted to prevent damage to the pipe 112 and/or the pipe string 116 during operation of the pipe handling system 102. In one embodiment, the integrated safety system 1400 is controlled electronically using the control unit 312. The integrated safety system 1400 is adapted to prevent the release of the gripper 104 before the gripper 119 grips the pipe 112 and/or the pipe string 116. For example, in a pipe driving operation, the control unit 312 may initially activate the gripper 104 actuator 106 to grip the pipe 112. The control unit 312 may then

activate rotation of the gripper 104 to connect the pipe 112 to the pipe string 116. The control unit 312 can then release the gripper 119 while still gripping the pipe 112 and the pipe string 116 with the gripper 104. The control unit 312 will prevent the release of the pipe 112 until the gripper 119 again grips the pipe 112 and the pipe string 116. As soon as the gripper 119 has gripped the pipe 112 again, the control unit will allow the gripper unit 104 to release the pipe 112.

The integrated safety system 1400 may be able to monitor the proper amount of tightening torque in the pipe 112 threads during tightening. This ensures that the threads are not damaged during tightening and that the connection is secure. Examples of suitable security systems are illustrated in US 6,742,596 and patent applications US 2005/0096846, 2004/0173358 and 2004/0144547.

In another embodiment, the integrated security system 1400 can incorporate the positioning system 900. The positioning system 900 sends a signal to the control unit 312 which gives the gripping device 104's status in relation to the pipe 112. In other words, the positioning system 900 indicates to the control unit 312 when the gripping device is gripping the pipe 112 or not. In operation, after the gripper 104 grips the pipe 112, the positioning system 900 sends a signal to the control unit 312 indicating that the pipe 112 is gripped and that it is safe to lift the gripper 104. The gripper 104 is manipulated by the drive mechanism 108 and/or the hoist system 110 to engage the pipe 112 to the pipe string 116. The control unit 312 can then open the gripper 119 to release the pipe string 116. The pipe

112 is lowered and grasped again by the gripper 119 as described above. The control unit 312 then releases the gripper 104 from the tube 112. The positioning system 900 informs

moves the control unit 312 when the gripper 104 is safely released from the pipe 112. The gripper 104 can then be removed from the pipe 112 without marking or damaging the pipe 112.

The integrated security system 1400 can incorporate a sensor 1000 in another embodiment. The sensor 1000 sends a signal to the control unit 312 when the stop collar 1002 is close to the pipe 112. Therefore, a signal is sent to the control unit 312 when the gripper 104 approaches the pipe 112 and/or the pipe string 116, before the stop collar 1002 hits the pipe 112. The control unit 312 can then stop the gripper 104 movement, and in some cases raise the gripper, depending on the operation. The stop of the gripper prevents weight from being placed on the pipe 112 when it is not desired. In another embodiment, the signal can initiate a visual and/or an audible alarm to allow an operator to make the decision about what necessary steps must be taken.

In yet another embodiment, the integrated security system 1400 may incorporate the trigger 1300. The trigger 1300 may send a signal to the control unit 312 when the trigger begins to activate the slow release of the gripper. The controller 312 can then override the trigger 1300, lift the gripper 104 and/or initiate the actuator

106 to override the trigger 1300 depending on the situation. For example, if the gripper slow release is initiated by the trigger 1300 before the gripper 119 grips the tube 112, the control unit may override the trigger 1300 and thereby prevent the gripper 104 from releasing the tube 112.

In yet another embodiment, the integrated safety system 1400 is adapted to control the compensator 700 via the control unit 312. When the compensator 700 is initiated during the coupling of the pipe 112 to the pipe string 116, the compensator 700 can send a signal to the control unit 312. The compensator 700 can measure the distance that the pipe 112 has moved downwards during connection. The distance that the compensator 700 has traveled would indicate whether the connection between the pipe 112 and the pipe string 116 was made. With the connection made, the control unit 312 can now allow the gripper unit 104 to release the pipe 112 and/or the compensator to return to its original position.

In an alternative embodiment, the integrated safety system can be one or more mechanical locks that prevent operation of individual control units for one rig component before another rig component is engaged.

In operation, the gripping device 104 is attached to the drive mechanism 108 or the swivel 200 which is connected to the rig 100's hoisting system 110. The pipe 112 is engaged by a pipe clamp (not shown). The pipe clamp may be any pipe clamp known in the art and may be connected to the pipe handling system 102 by any method known in the art. The pipe clamp then brings the pipe 112 close to the gripper 104. In an alternative embodiment, the gripper can be brought to the pipe 112. The gripper 104 is then lowered by the hoist system 110, or the pipe clamp raises the pipe 112 relative to the gripper 104 until the V-belt 208 is inside the pipe 112. When the gripper 104 stop collar 1002 comes close to the pipe 112, the sensor 1000 can send a signal to the control unit 312. The control unit 312 can then stop the relative movement between the gripper 104 and the pipe 112.

With the gripper 104 in the desired location, the control unit 312, either automatically or at the command of an operator, activates the actuator 106. At least the primary actuator of the actuator 106 is activated to drive the V-belt 208 into engagement with the pipe 112. One or more redundant actuators can be activated either simultaneously with or after the primary actuator is activated. The primary actuator will ensure that the V-belt 208 grips the pipe while the redundant actuators will ensure that the pipe 112 is not released prematurely from the gripping device 104. The operation of the primary actuator and the redundant actuators is monitored by the control unit 312 and/or the operator.

When the actuator 106 activates the gripper 104, the positioning system 900 can send a signal to the control unit 312 regarding the location of the V-belt 208 in relation to the pipe 112. After engagement with the pipe 112, the drive mechanism 108 and or the hoist system 110 can carry the weight of the pipe 112 for connection with the pipe string 116. Pipe handle The ring system 102 then lowers the pipe 112 until the pipe 112 engages the pipe string 116. The drive mechanism 108 can then rotate the pipe 112 to connect the pipe 112 to the pipe string 116. During the connection of the pipe 112 to the pipe string 116, the compensators 700 can compensate for any axial movement of the pipe 112 relative to the drive mechanism 108. The compensation prevents damage to the pipe 112 threads. The compensator 700 can indicate to the control unit 312 the degree of connection between the pipe 112 and the pipe string 116. When the drive mechanism 108 transfers rotation to the pipe 112 via the gripper 104 and the V-belt 208, the swivel takes care of the communication between the rotating components and the control unit or any other fluid sources or electrical sources. After the connection between the pipe 112 and the pipe string 116 is tightened, the gripper 119 can release the pipe string while the gripper continues to bear the weight of the pipe 112 and the pipe string 116. The hoist system 110 then sends the pipe string 116 to the desired location. The gripper 119 then grips the pipe string 116. The control unit 312 can then release the V-belt 208 either by using the trigger 1300 or by deactivating the actuator 106 to release the pipe string 116. During this sequence, the integrated safety system 1400 can prevent the pipe string 116 from being accidentally dropped in the well hole 115. The process can then be repeated until the pipe string 116 has the desired length. When the pipe string 116 is lowered into the wellbore 115, drilling fluids can be pumped into the pipe string through the grabber 104. The drilling fluids flow through the flow path 206 (shown in Figure 2) in the grabber 104. A gasket 204 in the seal 202 prevents the drilling fluids from accidentally escaping from the top of the drill string 116.

After the pipe 112 and pipe string 116 are lowered, the gripper 104 can then be used to grip the equipment 114 in the manner described above. In one embodiment, the equipment is the cement plug sluice 1200/1200A shown in Figures 12A-12B. The gripping device 104 first grips the upper pipe length 1202 and then the cement plug sluice 1200 is connected to the pipe string 116. Then a first plug 1208 is dropped into the pipe string, either by the control unit 312 or manually by an operator. Cement can then be pumped into the cement plug sluice 1200 via the fluid inlet 1205 and flow down the pipe string 116 behind the first plug 1208. The swivel 1204 allows the cement to be pumped into the cement plug sluice 1200 while the drive mechanism 108 rotates and/or moves the pipe string back and forth, if necessary. After the required volume of cement has been pumped into the pipe string 116, the control unit 312 or an operator releases a second plug 1210. The second plug 1210 can be pushed down the pipe string using any suitable fluid such as drilling fluid. The second plug 1210 continues to move down the pipe string 116 until it lands on the first plug 1208. The cement is then allowed to dry in an annulus between the pipe string 116 and the wellbore 115. The cement plug sluice 1200 can then be removed from the pipe string 116 and then disconnected from the grabber 104 .

With the pipe string 116 cemented in place, the gripper 104 can be removed from the actuator 106. One of the modular grippers 804, shown in Figure 8, can then be connected to the actuator 106 to accommodate a different size pipe. A new pipe string 116 can be built up and driven into the cemented pipe string 116 in the same way as described above. The new pipe string can be equipped with a milling and/or drilling tool at its lower end to be able to mill out scrap (debris) in the pipe string 116 and/or drill the well hole 115. The same procedure as described above is used to drive and set this pipe string 116 into the wellbore. This process can be repeated until the run of pipes is complete. This process can be reversed to remove pipe from the wellbore 115.

In yet another embodiment described herein, an apparatus is provided for gripping a tube to be used with a top drive machine. The apparatus includes a coupling at one end for rotationally attaching the apparatus to the top drive machine and one or more gripping elements at a second end for gripping the tube. Further, the apparatus includes a primary actuator configured to move and hold the gripping members in contact with the pipe and a backup assembly adapted to hold the gripping member in contact with the pipe.

In yet another embodiment, the primary actuator is operated fluidically.

In yet another embodiment, the primary actuator is electrically operated.

In yet another embodiment, the backup assembly comprises a selectively operated redundant actuator.

In yet another embodiment, the primary actuator is operated hydraulically.

In yet another embodiment, a monitor is connected to a control unit for monitoring the condition of a backup assembly.

In yet another embodiment, the monitor monitors the condition of the primary actuator.

In yet another embodiment, the backup assembly includes a one-way valve that operates in conjunction with the primary actuator to ensure that the primary actuator remains operational in the event of a hydraulic failure.

In yet another embodiment, the backup assembly further includes an additional fluid source to ensure that the primary actuator remains operational in the event of a hydraulic failure.

In yet another embodiment, a first swivel is configured to communicatively couple the primary actuator to a fluid source. In addition, a second swivel can be connected to the backup assembly that is configured to communicatively connect the backup assembly to the fluid source. In addition, a second fluid source can be provided.

In yet another embodiment, the coupling includes a lock to prevent the apparatus and top drive machine from rotating independently of each other. Furthermore, the lock may include a shaped sleeve for engagement with a shaped outer diameter on the top drive machine and apparatus. Alternatively, the lock may include two or more link members configured to encircle the coupling, and one or more gripping jaws on an interior surface of each link member, wherein the one or more gripping jaws are configured to grip the apparatus and top drive machine.

In yet another embodiment, a trigger may be actuated by applying weight to the apparatus to actuate a fluid piston. Furthermore, the fluid operated piston can be connected to a resistor to constrict fluid flow. In addition, the fluid resistance may serve to release the gripping members from the tube by applying a substantially constant force applied over time.

In yet another embodiment described herein, an apparatus is described for gripping a pipe for use in a wellbore. The apparatus may include a gripping member for gripping the tube in which the gripping member is coupled to a rotating mandrel. Furthermore, the apparatus can include an actuator for activating the gripping element and a locking element for locking the gripping element in engagement with an internal diameter in the pipe. In addition, the apparatus may include a swivel for connecting the actuator to the gripping member.

In yet another embodiment, the actuator comprises one or more chambers which are controlled by fluid pressure. Furthermore, the fluid pressure can activate a piston.

In yet another embodiment, the locking element includes one or more pressure chambers which are connected to a fluid source.

In yet another embodiment, the locking element is one or more one-way valves provided between a fluid source and one or more pressure chambers.

In yet another embodiment, a control unit is provided for monitoring the fluid pressure in the one or more pressure chambers.

In yet another embodiment, a trigger is included which is activated by applying a weight to the gripper to activate a fluid operated piston. Furthermore, the fluid-operated piston can be connected to a fluid resistance for limiting fluid flow. In addition, the fluid resistance may serve to release the gripping elements by applying a constant force over time.

In yet another embodiment described herein, an apparatus is described for gripping a pipe for use in a wellbore. The apparatus may include a set of V-belts which may be connected to a rotating mandrel to engage the inner diameter of the pipe. Furthermore, the apparatus may include a plurality of fluid chambers to activate the V-belt and a swivel to fluidly connect a fluid source to the plurality of fluid chambers.

In yet another embodiment, the chambers comprise one or more primary actuators and one or more redundant actuators.

In yet another embodiment, the redundant actuator has a locking element.

In yet another embodiment, the locking element comprises a one-way valve configured to maintain pressure in the redundant actuator. Furthermore, the one-way valve may allow one-way flow into at least one of the fluid chambers.

In yet another embodiment, the fluid source supplies a hydraulic fluid.

In yet another embodiment, the fluid source comprises a pneumatic fluid.

In yet another embodiment, a control unit is provided for monitoring at least one of the fluid chambers.

In yet another embodiment, a sensor may be coupled to a stop collar, wherein the sensor is configured to communicate to the control unit when the stop collar engages the pipe.

In yet another embodiment, a control line may be connected to the swivel and the plurality of fluid chambers.

In yet another embodiment described herein, a method for connecting a pipe is described. The method includes providing a fluid pressure from a fluid source and conveying the fluid pressure through a swivel to a plurality of chambers. Furthermore, the swivel can have two or more annular seals located in a recess on each side of the fluid inlet. The method further includes activating a gripping member to grip the tube, wherein the gripping member is actuated by applying a fluid pressure to a piston within the plurality of chambers. The method may additionally include rotating the tube using the gripping member and moving a pressurized fluid into a cavity between the two or more annular seals and the recesses in response to rotating the tube. Furthermore, the method may include continuing to deliver the fluid source through the swivel and into the chambers via the swivel during rotation.

In yet another embodiment, the method further includes locking at least one chamber of the plurality of chambers upon activation, wherein locking the at least one chamber may include flowing fluid through a one-way valve.

In yet another embodiment, the method further includes monitoring at least one chamber of the plurality of chambers with a controller. In addition, the gripping member may be operatively connected to a top drive machine. Furthermore, the gripping element can be rotated by the top driven machine.

In yet another embodiment described herein, a pipe handling system is described. The pipe handling system includes a pipe pulling device connected to an elevator system and a gripping device. In addition, the pipe handling system includes a cement plug sluice configured to selectively have a tubular housing for receiving the gripping member, and one or more plugs located within the tubular housing configured to perform a cementing operation.

In yet another embodiment, a one-way valve may be located within the tubular housing configured to prevent fluid flow from the sluice to the gripper. A control unit and one or more cementing plug activators to remotely release the one or more plugs can be provided.

In yet another embodiment, a swivel is provided which allows fluid to be pumped into the sluice while the attraction device rotates the sluice.

In yet another embodiment, the gripping element comprises a spear.

In yet another embodiment, the gripping element comprises an external pipe gripper.

In yet another embodiment described herein, a method for completing a wellbore is described. The method includes providing a pipe handling system which is connected to an elevator system in which the pipe handling system comprises a gripping device, an actuator and a pulling device. The method further includes gripping a first pipe using the gripping apparatus and connecting the first pipe to a pipe string by rotating the first pipe using the pulling apparatus, where the pipe string is partially inside the wellbore. In addition, the method may include lowering the first tube and the tube string and releasing the first tube from the gripper. The method may further include gripping a cementing tool using the gripping apparatus and connecting the cementing tool to the first pipe by rotating the cementing tool. In addition, the method may include flowing cement into the cementing tool and cementing at least a portion of the pipe string into the well hole.

In yet another embodiment, the method includes preventing cement from flowing into contact with the gripper by means of a one-way valve.

In yet another embodiment described herein, a trigger is described for releasing the gripper from a pipe. The trigger includes a piston and a piston cylinder operatively connected to a mandrel in the gripper. The trigger further includes a fluid resistance configured to fluidly couple a trigger chamber to the piston by providing a constricted flow path. In addition, the trigger may include a shoulder adapted to engage a tube and increase pressure in the trigger chamber when weight is applied to the shoulder, wherein continued weight on the shoulder slowly activates the piston thereby slowly releasing the gripper from the tube.

In yet another embodiment described herein, a security system for use with a pipe handling system is described. The safety system includes a sensor adapted to track the movement of a V-belt for activation of a gripper, wherein the sensor sends a signal to a control unit when the gripper is in a position consistent with the gripper engaging the pipe.

In yet another embodiment, the sensor comprises a trigger actuated by means of a wheel coupled to an arm, wherein the wheel moves along a track coupled to an actuator as the actuator moves the V-belt ring. In addition, the track may have one or more detents configured to move the wheel radially and actuate the trigger when the wheel rolls.

In yet another embodiment described herein, a method is described to

monitor a pipe handling system. The method involves moving a gripper toward a pipe and engaging a sensor located on a stop collar on the gripper to an upper end of the pipe. The method further includes sending a signal from the sensor to a control unit indicating that the pipe is in an engaged position and stopping movement of the gripper relative to the pipe in response to the signal. In addition, the method may include gripping the tube with the gripping apparatus.

In yet another embodiment, the method further includes monitoring a position of one or more engaging elements in the gripper relative to the pipe using a second sensor, and sending a second signal to the control unit indicating that the gripper is engaged with the pipe.

In yet another embodiment, the method further includes connecting the pipe to a pipe string held by a retaining ring on the drill deck and verifying that the pipe connection is secure.

In yet another embodiment, the method further includes allowing the control unit to release the retaining ring after verifying that the pipe coupling is secure and that the gripper is secured.

Claims (34)

1. Procedure for handling a pipe, characterized in that it includes: gripping the tube with a gripping device; sending an electronic signal to a control unit indicating that the gripper is gripping the pipe; and to control activation of the gripper using the control unit to prevent accidental release of the pipe. 2. Method according to claim 1, wherein it further comprises activating a top-driven machine using the control unit to rotate the gripper and the tube. 3. Method according to claim 1 or 2, wherein it further comprises connecting the pipe to a pipe string which is carried by a holding device, and controlling activation of the holding device using the control unit to prevent the pipe string from accidentally being released. 4. Method according to claim 3, where it further comprises: releasing the pipe string from the holding ring apparatus while the pipe and pipe string are carried by the gripping apparatus; lowering the pipe and pipe string through the holding ring apparatus; grasping the tube with the holding ring apparatus; and using the control unit to prevent the gripper from releasing the pipe before both the pipe and the pipe string are carried with the holding ring apparatus. 5. The method according to claim 4, wherein it further comprises activating the holding device using the control unit to thereby grasp the pipe. 6. Method according to claim 5, where it further comprises sending an electronic signal to the control unit indicating that the holding device is gripping the pipe, and then activating the gripping device using the control unit to thereby release the pipe. 7. Method according to any one of claims 1-6, which further comprises monitoring a position of the gripping device in relation to the pipe, and sending an electronic signal to the control unit indicating the position of the gripping device. 8. Method according to claim 7, wherein monitoring the gripper's position comprises tracking a position of a slip ring or a piston rod in a piston assembly which can be operated to activate the gripper. 9. Method according to claim 7, where monitoring the position of the gripping device comprises monitoring a distance the gripping device has in relation to the pipe. 10. A method according to any one of claims 1-9, wherein it further comprises measuring a pressure amount or temperature in a piston assembly operable to activate the gripper, and sending an electronic signal to the control unit indicating the pressure amount or temperature. 11. A method according to any one of claims 2-10, wherein it further comprises activating a top drive machine to rotate the gripper and the pipe and thereby connect the pipe to the pipe string to form a pipe connection. 12. Method according to claim 11, where it further comprises monitoring an amount of torque used when creating the pipe connection, and sending an electronic signal to the control unit indicating the amount of torque. 13. Method according to claim 11, where it further comprises monitoring an amount of distance that a compensator moves while the pipe connection is established, in which the compensator is connected to the gripping device, and sending an electronic signal to the control unit indicating the amount of distance that the compensator moves. 14. A method according to any one of claims 1-13, wherein it further comprises activating a hoist assembly using the control unit to thereby raise or lower the gripper. 15. Pipe handling system, characterized in that it includes: a gripping device; and a control unit operable to receive an electronic signal indicating a position of the gripper, wherein the control unit is operable to control activation of the gripper to prevent accidental release of a tube carried by the gripper. 16. Pipe handling system according to claim 15, wherein it further comprises a top driven machine, wherein the control unit is operable to activate the top driven machine to rotate the gripper. 17. Pipe handling system according to claim 15 or 16, where it further comprises a holding device, in which the control unit can be operated to control activation of the holding device to prevent a pipe string carried by the holding device from being released by accident. 18. Pipe handling system according to claim 17, where it further comprises a sensor that can be operated to monitor a position of the holding ring apparatus and can be operated to send an electronic signal to the control unit indicating the position of the holding ring apparatus. 19. Pipe handling system according to any one of claims 15-18, wherein it further comprises a sensor operable to monitor the position of one or more engaging elements of the gripping apparatus, and operable to send the electronic signal to the control unit indicating the position of the engaging element or elements position. 20. A pipe handling system according to any one of claims 15-19, further comprising a top drive machine operable to rotate the gripper. 21. Pipe handling system according to any one of claims 15-20, wherein it further comprises a sensor operable to monitor an amount of torque supplied by the pipe, and operable to send an electronic signal to the control unit indicating the amount of torque. 22. Pipe handling system according to any one of claims 15-21, wherein it further comprises a hoist assembly which can be operated using the control unit to thereby raise or lower the gripper. 23. Procedure for operating a pipe handling system, characterized in that the procedure comprises: moving a gripper against a pipe; detecting the presence of an upper end of the pipe using a sensor located on the gripper; sending a signal from the sensor to a control unit indicating that the pipe is in a position for engagement; stopping movement of the gripper relative to the tube in response to the signal; and to grip the tube with the gripper. 24. Method according to claim 23, where the pipe is stopped before it comes into contact with a stop collar in the gripper. 25. Method according to claim 23 or 24, where it further comprises monitoring a position of one or more engaging elements in the gripping device in relation to the pipe using a second sensor, and sending a second signal to the control unit indicating that the gripping device is engaged with the tube. 26. Method according to claim 25, where monitoring a position of one or more engagement elements comprises monitoring a whole spectrum of positions for the engagement elements. 27. Method according to claim 25, where monitoring a position of one or more engagement elements comprises monitoring a piston for activating the engagement elements. 28. Method according to claim 27, where the second sensor comprises a wheel connected to the piston. 29. Method according to claim 25, where it further comprises connecting the pipe to a pipe string held by a retaining ring on the drill deck and verifying that the pipe connection is secure. 30. Method according to claim 29, where it further comprises, after verification that the pipe connection is secured and that the gripping device is secured, that the control unit allows the release of the retaining ring. 31. Pipe handling system, characterized in that it includes: a pipe gripping apparatus having a gripping mechanism; a sensor adapted to track movement of the gripper mechanism, wherein the sensor sends a signal to a control unit when the gripper is in a position consistent with the gripper being engaged with the pipe. 32. Pipe handling system according to claim 31, where the sensor comprises a trigger which is activated by a wheel which is connected to an arm, in which the wheel moves along a track which is connected to an actuator, when the actuator moves the gripping mechanism. 33. Pipe handling system according to claim 32, wherein the track has one or more breaks configured to move the wheel radially and activate the trigger when the wheel rolls. 34. Pipe handling system according to claim 31, where it further comprises an indicator sensor for indicating a position of the gripping device in relation to the pipe.