GB2493512A

GB2493512A - Oil derrick breakout unit

Info

Publication number: GB2493512A
Application number: GB201113090A
Authority: GB
Inventors: Peter Holland
Original assignee: Northern Hydraulic Cylinder Engineers Ltd
Current assignee: Northern Hydraulic Cylinder Engineers Ltd
Priority date: 2011-07-29
Filing date: 2011-07-29
Publication date: 2013-02-13
Anticipated expiration: 2031-07-29
Also published as: GB2493512B; GB201113090D0

Abstract

A breakout unit is mountable on an elongate body and comprises a breakout gripper 52 and a motorisation gripper 51 connected together by an actuator 53. The actuator 53 is configured to generate relative movement between the breakout 52 and motorisation grippers 53 and each gripper is provided with a clamping means adapted to selectively clamp in place the gripper with respect to an elongate body upon which the gripper may be mounted. A breakout gripper 52 includes at least one actuator arranged to exert a force on an object adjacent the breakout gripper along the longitudinal axis of the elongate body.

Description

OIL Rig Derrick Breakout Unit

Field of the Invention

The present invention relates to oil rig derricks and iii particular to a device for moving such a derrick along skids upon which it is mounted.

Background of the Invention

On many oil rigs the drilling pipe is mounted on a derrick. In many drilling situations it is desirable to be able to move the position of the drilling pipe with respect to thc entrance into the well. Tl'his is particularly so whet-c wells that have been used previously arc revisited for further extraction, which often involves directing the drill to one side or another of the previously exploited well. The drilling pipe can be used in one of t-wo ways. Either the whole rig can he moved, which is not desirable, or the derrick in which the drill pipe is niounted can be moved, if that is the derrick is suitably mounted on the oil rig to provide for such rnovetnent.

It is common for the derrick is itself to he nv)unted on two sets of rails, one mounted perpendicular to and below the other. Tn fact, the derrick is mounted on an upper set of rails, and that set of rails is mounted on alower set of rails. To facilitate movement, each rail is provided with a skid system. This is a hydraulically operated piece of equipment that allows the derrick to be pulled along the 1-ails.

Whilst the skid systems provided to move the derrick along the skids ought to be capable of moving the derrick, it is often found that they are not in fact capable of doing so. An oil rig derrick is itself a heavy object, often in excess of two hundred tonnes. The derrick may carry a quantity of drill pipe having a weight greater than the weight of the derrick. hence, the friction forces between the derrick and the rails upon which it is mounted can he very significant, and niust be overcome by the skid system if the derrick is to he moved along the skids.

Whei-e there is a need to move the derrick, this need is infrequent. lbe envi -onmental conditions where oil rigs are deployed are harsh and liable to cause corrsin. The cornhination of forces arising from friction due to the mass of the derrick and the drill pipe it carries acting on the skids and corr)sion het'veen the skids and the rails often cannot he overcome by the hydraulic tanis of the skid systems.

The present solution within the indusrry is to off load at least some of the drill pipe carried by the derrick to i-educe the mass and therefore the friction force that must he ovei-come hy the hydraulic ranis of the skid system. Whilst this works, it is very cosfly, and involves a certain element of danger. If drill pipe is to be off loaded, a harge must he hrought along side the rig to receive the drill pipe. This involves cost.

Further, transferring heavy objects from an oil rig to a barge at sea is hazardous. Still further, during the time when the drill pipe is being off loaded, and then re-loaded the oil rig is out of production, and hence not generating revenue.

It wotdd therefore be desirable to provide an improved system for moving a derrick on an oil rig.

Brief Description of the Drawings

In the drawings, which ifiustrate pi-eferi-ed embodiments ofa break out unit according to the in ennon: Figure 1 is schematic plan view of a derrick mounted on two sets of rails running perpendicular to one another; Figure 2 is-a schematic side view of the derrick illustrated in Figure 1, with the breakout unit of the invention in position; Figures 3a to 3e illustrate the breakout unit of the invention iii cross-section in different spates of actuatioii; Figure 4a is a plan view of the break out unit of the invention; Figure 4b is all end vlew of the break out unit Elf the invention illustrated in Figure 4a; Figure 5 is an end view ola skid beam upon which the breakout unit of the invention sits; Figure 6 is a cross-sectional side view of the breakout unit of the invention positioned for moving the derrick; Figure 7a is a schematic represention of a hydrauhc hand pump of the invention; Figure 7h is a hydraulic circuit diagram of hydraulic hand pump and the hydi-aulic circuits of which the pump forms a part; and Figure 8 illustrates plan and side views of a skid clamp of the npe known in the prior art.

Detailed Description of the Preferred Embodiments

Figure 1 illustrates the general arrangement of a derrick 1 mounred on an upper set olrails 2, the upper set of rails being mounted on a lower set of rails 3 and lying perpendicular thereto.

The derrick I is arraiged to slide on the upper set of rails 2, with the upper set of rails 2 being arl--inged to slide on the lower set of rails 3. Tn rhis way, the derrick 1 can he positioned anywhere within the bounds of the four rails.

Figure 2 is a side view of the general arrangement illustrated in Figure 1 and shows a skid unit 4 and a breakout unit 5. The skid unit 4 is essentiailv a skid svstelll of the type i-hat is already known in the art and comprises a grippet 41 and a ram 42. lIhis skid system is illustrated in more detail in Figure 8, which is described in greater detail below.

lihe break out unit 5 comprises a motot-isation gripper 51 and a bi-ealtout gripper 52, which are described in greater detail below with reference to Figures 3 to 7.

Referring now to Figures Pa, 4h and 6, the breakout umt 5 comprises a nittoris wIn gripper 51 and a breakout gripper 52. The function of die motorisation gripper Si is to move the breakout gripper 52 along the rail 2, whereas the function of the breakout gripper 52 is to exert a force on the derrick 1.

The motorisarion gI-ipper 51 is connected to the breakout gripper 52 by an actuator, which in the illustrated example is a hydraulic rain 53, respective ends of the ram 53 being attached to bifurcated brackets 54, 55 by pills 56. By extending and retracting the ram 53 the distance between the motorisation gripper and the breakout gripper may be adjusted. The inotorisation gripper includes a top plate 57 and a clamping plate 58 mounted below the top plate and connected thereto by a pair of spaced apart actuators 59 and side plates that are attached to the top plate 57 by fasteners (threaded bolts in the fflusftated example). The side plates 60 include portions 62 that extend under the rail 2. \K/hen the actuators 59 (which are hydraulic rams) are energised to extend them, the clamping plate 58 is forced against the upper surface of the rail 2, and the upper surfaces of portions 62 of side plates 60 are brought into engagement with the underside of the rail 2.

When so arranged, the motorisation gripper 5! is held stationary. The hydraulic ram 53 may then he actuated to change the position of the breakout gripper 51 on the rail 2.

The break otit gripper 52 comprises a top plate 70 and a clamping plate 71. Side plates 72 are attached to the top plate 70 by fasteners 73, which in the present example are threaded bolts. The side plates 72 include portions 72a and 72b, which extend over a part of the top plate 70 and under a part of the rail 2 respectively. A number of actuators 74 (in the present example six hydraulic rams arranged in two rows of three) are situated between the top plate 70 and the clamping plate 71.

Each of the side plates 72 mounts an actuator 75 that is Lrranged with its longitudinal axis lying substantially paraliel with the longitudinal axis of the rail 2. Further, the clamping plate 71 mounts a plurality of actuators 76, agaIn each with its longitudinal axis lying substantially pal-allel to the rail 2. In the illustrated embodiment, the clamping plate 71 includes a recess in one end thereof bounded by downwardlly extending side walls 71a, and the undcrsidc of an upper surface 7W. Thc actuators 76 are mounted in the rccess.

The underside of the clampingplate 71 sits on the uppcr surface of the rail 2. When it is dcsiied to fix the position of the breakout gripper 52, the actuatots 74 are extended. This has the effect of lifflng the top plate 70 upwards and engaging the upper horizontal surface of the portion 72h with the underside of the rail 2 and thereby locking the breakout gripper 52 in place. This action also changes the pesition of the actuators 75 with respect to the actuators 76, bringing them to lie on substantially the same horizontal axis.

Figure 6 shows the breakout gripper 52 in position for moving or assisting in moving the derrick 1.

The actuators 74 are extended and hence the rail 2 is gripped between the clamping plate 71 and the portions 72b of the side plates 72, which are themselves attached to the top plate 70. The actuators 75,76 he on the same horizontal plane and are aligned with a pan 80 of the structure of the derrick 1. With the breakout gripper 52 fixed in position and the actuators 75, 76 lying in the same plane, the actuators 75, 76 are extended to push the pan 80 and hence the derrick 1 along the rail 2.

Figures 3a to 3e demonstrate the sequence of action of the breakout unit 5.

In Figure 3; the actuators 74 of the breakout gI-ipper 52 a'e extended, locking the hi-eakout gripper in place. The actuators 59 of the inotorisation gripper 51 are released.

In Figure 3b, the condition of the actuators 74 and 59 remains as in Figure 3a, hut the-acrjator 53 has been extended.

In Figure 3c, the actuators 74 of the breakout gripper 52 have been released and the actuators 59 of the niotorisation gripper 51 have been extended, locking the motorisation gripper 5! in place. The actuator

S

53, which is a douhk acting actt,atot, is then retracted, pulling the breakout gripper 52 along the tail 2 towards the motorisation gripper 51.

In Figure 3d, the actuators 74 have been eninded, locking the breakout gripper 52 in place. This beings die actuators 75, 76 to lie in a common place. They are then energised to extend them to overconle the forces resisting movement of the derrick I relative to the tail 2.

In Figure 3e, the acruatoi-s 75, 76 are shown in an at least parl-iallv extended state.

Figure 5 ifiustrates the skid rail 2 on which the derrick 1, skid unit 4 and breakotit unit 5 sit. The rail 2 is pro'ided with wear plates 81, 82 mounted on the upper and lower surfaces of the hori2ontal surface of the ail 2.

Figure 8 illustrates a skidder unit 4, which is of the same type as known in the art. The skidder unit 4 conipi-ises a skid clamp 80 which mounts a plurality of actuators 81 (eight in this example). \Vhen die actuators 8! are actuated the skid clamp 80 is clamped to the skid rail 2. The skid clamp 80 is attached to a hydraulic ram 82 by means of a coupling 83, with a further coupling 84 being attached to the piston of the ram 82. Tn use, the derrick 1 is attached to the coupling 84 by a suitalile pin.

When the derrick is to he moved, any locks holding the derrick in place are released and, assuming the skid unit 4 is to pull the derrick, the skid clamp 80 is positioncd such that the derrick I may he attached ru the coupling 84 of the ram 82 with the ram in an extended state. The skid clamp 80 is clamped on to the rail 2 and the ram 82 retracted, thereby pulling the derrick along the rails 2. Conversely, if the derrick is to he pushed, i-he skid unit is positioned oil the skid -ail 2 such that the derrick 1 may be attached to the coupling 84 of the rain 82 with the ram in a retracted stare.

Moing the derrick 1 with a skid unit 4 presents two problems. The first, as outlined above relates to the inability of the skid unit 4 to overcome the fbrces arising from friction and due to corrosion between the derrick and the skid tail. The second lies in the liability of the derthck to crab on the I-ails as it is being pulled or pushed I the ram 82. Typically, a skid unit 4 is provided on each rail, so that the derrick I is pushed or pulled along the axes ()ft'.v() spaccd apart rails. However, the arrangement olcouplings 83,84 mean that sonic ct-abbitig can OCCUr.

lihe combination of a skid unit 4 pulling the derrick 1 and the breakout unit 5 pushing the derrick can lessen the likelihood of die derrick crabbing on the tails.

Figures 7aand 7b ifiustrate the hydraulic hand pump unit 90 and associated hydraulic circuit for cnergising the actuators of thc breakout unit 5. The pump unit 90 thdudes alow pressure high v(Aume pump 91 and a high pressure bw voiume pump 92. A handle 93 is pivotallv connected to a post 94 that is attached to a frame 95 in which the pumps 91, 92 are mounted. The handle 93 is attached to the pumps 91, 92 by a bifurcated bracket 96. In the exampk, the low pressure pump 91 genentes a pressure of 1500 psi and the high pressure pump a pressure of 5000 psi.

As can be seen from the hydraulic circuit 7b, the low pressure and high pressure pumps 9!, 92 are hvdraLdically connected. By provithag a low pressure high volume pump when the actuators are under only a modest load, the actuators can hc extended or retracted quickly. For cxample, the ram 53 may he extended and retracted reiafiveiv quickly to move the mototisauon gripper and the breakout gripper as shown in Figures 3a to 3e through the congurations shown in Figures 3a to 3d. However, in Figures 3d and 3e, where the breakout Ullit is in position for pushing the derrick 1, a higher pressure is required and hcncc the high pressure pump 92 must be used. This is achieed by opening i. vake 97, so tirat oil from the ow pressure pump 91 is clumped. When the li)w pressure pump 9! is again t-equit-ed, the valve 97 is closed.

The breakout unit has been described with reference to exerting a force on the derrick. This is so for the breakout unit mounted on the upper rail, but the breakout unit mounted on the lower rail, rather thtn exerting a foi-ce directly on the derrick, the force is exerted on one of die upper i-ails, causing the upper rail to move, and hence move the derrick which is mounted on the upper rails.

The present invention provides a device that is capable of generating a hrcakout force capable of moving the derrick of an oil rig. Further, the device is able to move itself along the rail upon which it is mounted and assist in moving the derrick to a desired position after initiating movement.

The object ro he moved in the above description is'a derrick. I lowever, the problem associated with the oil rig derrick may he found in other situations where a heavy object is mounted on a rail, and/or all object is mounted on a rail and situated in an environment where corrosion is likely to occur.

Claims

<claim-text>Claims 1. A breakout unit mountable on an elongate body, the breakout unit comprising a breakout gripper and a motorisation gripper connected together by an actuator, the actuator being configured to generate relative movement between the breakout and motorisation grippers, wherein each gripper is provided with a clamping means adapted to selectively dantp in pEace the gripper with respect to all elongate body upon which the gripper may he mounted, and wherein the breakout gripper inchides at kast one actuator arranged to exert a force on an object adjacent the breakout gripper along the Eengitudrnal axis of the elongate body.</claim-text> <claim-text>2. A breakout unit according to (Jaim 1, wherein the breakout gripper inchides a body and a chunping member tnountcd in the body and at least one actuator arranged to exert a force sekctively on the clamping member to cause rehitive movement between the body and file damping member.</claim-text> <claim-text>3. A breakout unit according to (ilaim 1 or 2, wherein die motonsation gripper indudes a body and a clamping member mounted in the body and at least one actuator arranged to exert a force selectively on the clamping member to cause relative moxement between the b(dy and the clamping member.</claim-text> <claim-text>4. A breakout unit according to Claim 2 or 3, wherein die body includes side member, at Eeast one base member arid a top member, wherein the base nemher extends to one side of the side member.</claim-text> <claim-text>5. A breakout unit according to Claim 4, wherein the base member extends inwardly of the side member.</claim-text> <claim-text>6.Ahreakout unit according to Cairn 4 or 5, wherein die top member extends to one side of the side member.</claim-text> <claim-text>7. A breakout unit according to Chdm 6, wherein the top member extends inwardly of the side member.</claim-text> <claim-text>8. A breakout unit according to any of Chints 2 to 7, wherein a reaction member is mounted in the body, and is fixed with respect thereto, and wherein the clamping mcmher is movabk with respect to the body and the reacfio member and wlieiein the at least one actuator is situated between the cFamping meniber and the reaction member.</claim-text> <claim-text>9.Al,reakout unit according to any of (ilalins 2 to 8, wherein a plurality of actuators are arranged to exert a force selectively on the damping member.</claim-text> <claim-text>10. A ht-eakout unit according to Claim 9, wherein the plurahty of actuators comprises an even number of actuators, and wherein half of the actuators are disposed to one side ofalongitudinal centre axis of the clamping member and half of the actuators are ehsposeel to another side of the longituehnal centre axis of the clamping member, the actuators being disposed equidistantly from the said longitudinal centre axis.</claim-text> <claim-text>I. A bi-ealtout unit according to any of Claims 4 to 7, comprising an even number of actuators, half the actuators mounted between the clamping member and the top member -associated with one of the side members and half the >tctuators mounted between the claniping member and the top member associated with the other of the side members.</claim-text> <claim-text>12. A breakoutunit according to any of Claims 2 to II, wherein the breakoutgrippermounts at least one actuator arranged to exert a foice on all object adjacent die breakout gi-ipper along the longitudinal axis of the elongate body in the clamping member.</claim-text> <claim-text>13. A breakout unit accoreling to any Claims 4 to 12, wherein each of the side members of the breakout gripper comprises an actuator arranged to exert a force on an object adjacent the breakout gripper along the longitudinal axis of the elongate body.</claim-text> <claim-text>14. A breakout unit according to Claim 13 when dependent on Clalin 12, wherein the actuator mounted in the clamping member is arranged to lie on the same axis as the actuators comprised in the side members when the clamping member is in a clamping position.</claim-text> <claim-text>15. A breakout unit according to any preceding claini, wherein the actuators are hydraulic actuators.</claim-text> <claim-text>16. A breakout unit according to Claim 15, further including a Iiydtaulic power source.</claim-text> <claim-text>17. A breakout unit according to Cairn 16, wherein thc hydraulic power source isa hand pump unit.</claim-text> <claim-text>18. A breakout unit according to Claim 17, wherein the hand pump unit comprises first and second pumps, one of the first and second pumps being configured to deliver hydraulic field at higher pressure and in smaller volume for each stroke of the pump than the other.</claim-text> <claim-text>19. A breakout unit according to Claim 18, wherein the hand pump indudes a lever and a bifurcated bracket, the bifurcated bracket attaching to the first and second pumps.</claim-text> <claim-text>20. A breakout unit according to Cairn 18 or 19, wherein the first and second pumps are connected by a common hydraulic circuit.</claim-text> <claim-text>21. A breakout unit according to Claim 20, wherein the hydraulic circuit indudes a valve associated with the pump arranged to deliver hydraulic fluid at lower pressure and in higher volume per stroke said valve being selectively opened to release hydraulic fluid from said pump to an unpressudsed reservoir.</claim-text> <claim-text>22. An assembly comprising at least one rail, an object mounted on the at least one rail and at least one breakout unit according to any of Claims 1 to 21, wherein one breakout unit is mounted on one rail, wherein the breakout unit is moveable along the rail and adapted to exert a force on the object in the longitudinal direction of the rail when clamped thereto adjacent the object 23. An assembly according to Claim 22, wherein the assembly comprises two parallel rails, and wherein a breakout unit according to any of Claims 1 to 21 is mounted on each of the rails.24. An assembly according to Claim 22 or 23, the assembly comprising at least one upper rail and at least one lower rail mounted below the at least one Erst rail and oriented perpendicular thereto, and wherein the lower rail has mounted thereon a breakout unit according to any of Claims 1 to 21.25. An assembly according to Claim 24, wherein the assembly comprises two parallel lower rails, and wherein a breakout unit according to any of Claims 1 to 21 is mounted on each of the rails.</claim-text>