Apparatus for gripping a downhole tubular

Abstract

A downhole tubular gripping and suspending apparatus adapted for gripping a downhole tubular and suspending said downhole tubular from said apparatus. The apparatus has a housing (2) and a bottom opening (6) for introducing said top end of said tubular into a reception chamber (5) via said bottom opening (6). External coupler gripping members (20) are mounted on said housing (2) and adapted to grip an exterior of the enlarged diameter part of the coupler Shoulder support members (30) are mounted on said housing (2) and adapted to engage under said shoulder (103) of a tubular top end received in said reception chamber (5).

Description

FIELD OF THE INVENTION

The present invention relates to an apparatus for gripping a downhole tubular for use in an oil and gas drilling system and the like.

BACKGROUND OF THE INVENTION

Drilling methods are known wherein a so-called top drive mechanism is used to rotate the string of drill pipe joints. Such a top drive mechanism comprises a body commonly suspended from a travelling block of a drilling rig and movable vertically along the well bore axis.

The top drive mechanism furthermore commonly comprises a motor (e.g. an electric or hydraulic motor) secured to the body and having a rotatable output member.

It is know to provide the top drive mechanism with an apparatus for gripping and suspending a downhole tubular. This apparatus is in general arranged beneath the motor of the top drive and interconnected thereto, so that not only the tubular can be raised and lowered but also a rotary motion can be imparted to the downhole tubular if desired, e.g. for drilling operations.

A known apparatus for gripping and suspending a downhole tubular includes a series of clamping jaws arranged in the housing of the apparatus and adapted to clampingly engage on the exterior of a drill pipe or casing pipe in a region remote from the top end of the pipe. This is done to avoid damage to the threaded top end of the pipe.

In the oil and gas drilling industry it is know to use tubulars wherein the top end is provided with an enlarged diameter coupler (the “box” as it is generally referred to for drill pipe, whereas the lower end is provided with a screwthreaded end referred to as the “pin”) or the threaded end of a casing pipe (which is often not provided with an enlarged diameter coupler).

Other tubulars handled by an apparatus for gripping and suspending as herein described are e.g. well linings.

It is generally known that a significant torque has to be exerted on a tubular in drilling operations. The known top drive mechanisms are found to be unsatisfactory in this regard.

A further issue is the safety of the known top drive mechanisms. Also in this regard the known mechanisms are found to be unsatisfactory.

OBJECT OF THE INVENTION

An object of the invention is to provide an improved apparatus for gripping and suspending a downhole tubular.

A further object of the invention is to provide an apparatus, which allows for the transmission of a high torque, without compromising the part of the tubular gripped by the apparatus.

A further object of the invention is to provide an apparatus, which can be operated safe and reliable.

SUMMARY OF THE INVENTION

The apparatus of the invention grips the coupler on the outside. As mentioned before drill pipe joints commonly have such a coupler (the box) which has a larger outer diameter than the drill pipe section and also is often made of a different steel and/or hardened, and commonly provided with a rugged coarse internal (conical) thread for interconnecting drill pipes. The gripping of the outside of the coupler can thus be effected with high loads on the coupler, without unacceptable damage to the coupler and also the diameter of the gripped surface is greater than the diameter of the pipe section. Both effects allow the transmission of a high torque to the drill pipe and a reliable grip on the coupler.

The apparatus also provides a support engaging the underside of the shoulder of the downhole tubular. This amongst others reliably prevents the tubular from disengaging from the apparatus and dropping down, e.g. into the well bore. This could e.g. be effective when the gripping members loose their grip on the coupler (e.g. the gripping members and/or the actuating means thereof becoming defective).

It is noted that the “shoulder” may be formed in different ways depending on the composition of the downhole tubular. One option is that the coupler itself, e.g. the lower end, forms the shoulder thereof. Also it is known to have drill pipes provided with an “upset” at the upper end thereof, which is commonly obtain by forging the upper end to obtain a section of increasing thickness and with a conical widening other diameter towards the upper end of the drill pipes. On top of this “upset” the coupler is then fitted, e.g. welded. In such a drill pipe the upset could provide the “shoulder” under which the shoulder support of the apparatus engages. This would even provide “drop down protection” of the drill pipe (or drill string of interconnected drill pipes) in the unlikely event that the coupler would become detached from the upset of the drill pipe, e.g. due to a defective or damaged weld.

Preferably the apparatus is designed such that upon insertion of the tubular top end into the reception chamber first the one or more shoulder support members are brought into their active position, then the shoulder is brought to bear on the one or more shoulder support members (e.g. by lifting the apparatus with respect to the tubular). Thereafter the gripping members are brought into tight gripping engagement with the coupler.

It is envisaged that the apparatus according to the invention is integrated in a top drive mechanism, but other applications, e.g. for lifting etc. of downhole tubulars in oil and gas drilling operations and the like are also feasible.

The invention achieves one or more of the above objectives by providing an apparatus which comprises:

a housing having a reception chamber with at least a bottom opening for introducing said top end of said tubular into the reception chamber via said bottom opening;

external coupler gripping means including:

• • one or more coupler gripping members moveable mounted on said housing and adapted to grip an exterior of the enlarged diameter part of the coupler of a tubular top end received in said reception chamber,
  • actuating means that cause movement of said one or more coupler gripping members between an inactive position, allowing introduction of said top end of said tubular into said reception chamber, and an active position, wherein said coupler is gripped by said coupler gripping members;

shoulder support means including:

• • one or more shoulder support members moveable mounted on said housing and adapted to engage under said shoulder of a tubular top end received in said reception chamber,
  • actuating means that allow displacement of each shoulder support member between an inactive position, allowing introduction of said top end of said tubular into said reception chamber, and an active position, wherein each shoulder support member engages under said shoulder.

Further advantageous embodiments of the apparatus are disclosed in the appended claims and the description.

The invention also relates to a top drive mechanism including an apparatus for gripping and suspending a downhole tubular as herein described.

The invention also relates to a drilling rig including such a top drive mechanism, as well as to a drilling method wherein use is made of the apparatus for drilling and suspending a downhole tubular as herein described.

The invention will now be described in more detail referring to the description wherein a preferred embodiment is disclosed with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows in longitudinal section a preferred embodiment of an apparatus for gripping and suspending a downhole tubular according to the invention, the left-hand half with the coupler gripping members and shoulder support members in active position and the right-hand half with these members in inactive position,

FIG. 2 shows on a larger scale the lower part of the apparatus of FIG. 1,

FIG. 3 shows a cross section along the line III-III in FIG. 2 with the shoulder support members in active position,

FIG. 4 shows a cross section along the line IV-IV in FIG. 2 with the coupler gripping members in active position,

FIGS. 5a-f show in different successive stages the gripping of a tubular top end using the apparatus of FIG. 1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

FIGS. 1 and 2 show a downhole tubular gripping and suspending apparatus 1 adapted for gripping a downhole tubular 100 and suspending said downhole tubular 100 from said apparatus 1.

The apparatus 1 as depicted is adapted to be integrated into a top drive drilling mechanism. Here the apparatus 1 has a housing 2 fitted with a central shaft 3, which central shaft 3 is provided with a connector (not shown) for connecting the central shaft to a motor of a top drive drilling mechanism.

As is generally known a top drive drilling mechanism is movable up and down in a drilling rig, e.g. suspended from a travelling block of the rig, so that the gripped and suspended tubular, e.g. a string of drill pipes or casing pipes can be raised or lowered (into the well bore). By its connection to the top drive motor, the housing 2 can be made to rotate and thereby the gripped and suspended tubular can also be made to rotate, e.g. for effecting rotation of a drill bit or the like connected to the tubular. Such a rotary top drive mechanism could also be employed for interconnecting and/or decoupling screwthreaded tubulars.

The tubular 100 here is a common drill pipe, e.g. of a 30 ft length, having a tubular pipe section 101 of essentially uniform diameter and a top end provided with a coupler 102, generally called the box, for interconnecting tubulars 100. The coupler 102 has an enlarged diameter part of greater diameter than the pipe section 101. As is common for drill pipes of this type the top end of said tubular 100 also has an exterior shoulder 103, here a conical shoulder forming the transition between the pipe section exterior and the enlarged diameter part of the coupler 102.

As can be seen the coupler 102 has a tapering internal screw thread for interconnecting tubulars.

The housing 2 in general forms a reception chamber 5, here with a bottom opening 6 for introducing said top end of said tubular 100 into the reception chamber 5 via said bottom opening 6.

In the housing 2 external coupler gripping means are arranged for gripping the coupler 102 in such a manner that a tight grip is obtained and large torsional forces can be transmitted from the motor of the top drive to the coupler 102 and thus to the tubular 100.

In this embodiment the coupler gripping means include multiple coupler gripping members, distributed around the reception chamber for the tubular top end, so as to engage on the coupler at circumferentially spaced locations (see also FIG. 4).

The gripping members each are designed here as a clamping jaw 20, slidable along an associated guide 21 of the housing 2. The guides 21 each form a guide surface 22 tapering to a reduced diameter in the direction of the bottom opening 6 so that when the clamping jaws 20 advance towards said bottom opening 6 said clamping jaws move into their active position and a clamping surface 23 of each clamping jaw grips enlarged diameter part of the coupler 102. It is clear that such a clamping surface 23 can be of a grip enhancing design, e.g. with a roughened surface or the like.

The apparatus 1 further includes shoulder support means including one or more shoulder support members 30 moveable mounted on said housing and adapted to engage under said shoulder 103 of a tubular top end 100 received in said reception chamber 5.

In the embodiment shown here multiple shoulder support members 30 are provided, distributed about the reception chamber 5 for the tubular top end, here near the bottom opening 6, so as to engage under the shoulder 103 at circumferentially spaced support locations (see also FIG. 3). In this example three shoulder support members 30 are used.

In the design shown here each shoulder support member 30 is pivotable about an associated pivot axis 31, here about a pivot axis in a plane at right angles to the tubular 100 to be supported. In the shown version each support member 30 can be moved between a raised inactive position (see right-hand side in FIGS. 1, 2) and a lowered active position (see left-hand side in FIGS. 1,2).

Below each of the shoulder support members 30 the housing 2 provides a stop 32 for abutment of the shoulder support member 30 in its active position, so that the force by the tubular 100 on the shoulder support is directly transferred to the housing. It is noted that this force could be enormous, e.g. several hundreds of tonnes (e.g. over 200 tonnes), e.g. due to the weight of the drill string, the force required to pull the drill string from a well bore, etc.

In the FIGS. 1 and 2 it can be seen that each pivotable shoulder support member 30 is linked to a clamping member 20 located essentially above the shoulder support member, here via an associated connector rod 35.

In the design shown each connector rod 35 is pivoted to the support member 30 at a distance remote from the associated pivot axis 30 via a hinge 36. The other end of the rod 35 is pivoted to a clamping jaw 20, wherein the pivot axis 37 is guided in an elongated slot 26 of the jaw, extending essentially in the direction of the tubular to be supported.

For actuation of the clamping jaws 20 each jaw 20 is connected by an associated connecting rod 40 to a common ring member 41 which is slideable with respect to the housing 2. The connecting rods 40 are pivotable connected at both ends thereof.

In this embodiment the apparatus 1 has a spring 50 which is arranged here such that the spring urges the clamping jaws to their active position. The spring 50 here is common for all clamping jaws 20, but it can also be envisaged that each jaw 20 is associated with its own spring. The spring 50 here is arranged around the shaft and here is capable of exerting a significant force (the diameter of the shaft could e.g. be 300 mm). The spring here rests at its upper end against an support ring 51 fitted on the shaft 3. The lower end of the spring 50 acts on the ring member 41 and urges the ring member 41 downwards. Here intermediate ring members 42, 43 are positioned between the lower spring end and the ring member 41.

For compressing the spring 50, that is raising the ring member 41 in this embodiment, a power actuator, here a hydraulic actuator 70 is provided.

In this embodiment the actuator 70 also allows for the exertion of a downwards force on the ring member 41 and thus on the clamping jaws 20.

Here the actuator 70 is of annular design having an inner ring wall 71 supported by suitable bearings 72 on the shaft 3 (above the spring 50) and an outer wall 73 slidable up and down with respect to the inner wall 71. The outer wall 73 is connected by roller bearings 75 to an intermediate ring member 43.

The inner wall 71 is fitted with an annular piston 74 to form a lower and upper variable hydraulic chamber 76a, 76b to which hydraulic fluid can be supplied by a suitable hydraulic power pack.

As the tubular 100 here is a drill string the central shaft 3 here is provided with a central fluid channel 80 extending from an upper mouth to a fluid connector device extending in the reception chamber 5, said fluid connector device being adapted to connect to the tubular 100 so as to establish a fluid connecting between said tubular 100 and said central fluid channel 80, e.g. to feed drilling mud into the tubular during drilling operations.

In the embodiment shown the fluid connector comprises a tube part 85 connected to the housing 2 and in communication with the central fluid channel 80, said tube part being insertable into the top end of the tubular 100. There is a sealing arrangement provided for establishing a fluid seal between said tube part and the tubular top end.

In this embodiment the sealing arrangement includes a sealing ring 86 extending around the tube part 85 and slideable with respect to said tube part along a sliding section thereof, while maintaining a fluid seal between said ring 86 and said tube part 85, said ring 86 being dimensioned to sealingly engage the top end of the tubular 100.

A spring 87 is provided for urging said sealing ring 86 in sealing engagement with said tubular 100.

Referring to FIGS. 5a-f it will be shown how a tubular 100 can be gripped by the apparatus 1.

In FIG. 5a only the very top end of the tubular 100 is visible, the apparatus 1 being held above this top end. It can be seen that the clamping jaw 20 has been pulled upwards by means of the hydraulic actuator 70 so that it is in its inactive position. Thereby the shoulder support member 30 has also been brought in its raised inactive position.

The apparatus 1 is then lowered onto the top end of the tubular 100, so that the coupler 102 enters the reception chamber 5 via bottom opening 6. The front face of the tubular 100 comes to bear against the sealing ring 86. (see FIG. 5b).

Thereafter the hydraulic actuator 70 is operated to allow for expansion (lengthwise) of the spring 50, so that the jaws 20 are lowered along their guides 21. Before the jaws 20 actually clampingly engage on the coupler 102, the shoulder support members 30 reach their active position resting now on the stops 31 of the housing 2. (see FIG. 5c).

Once the shoulder supports 30 have reached their active position the apparatus 1 is lifted with respect to the tubular 100 which causes the shoulder 103 of the tubular 100 to come to firmly bear on the support members 30 (see FIGS. 5d and e).

It is preferred that only now the hydraulic actuator 70 is operated to press the clamping jaws 20 downward, so that the coupler is tightly gripped by the jaws 20 (see FIG. 5f).

It will be appreciated that as soon as the shoulder support members 30 are in their active position any risk of the tubular 100 falling out of the apparatus 1 is avoided. Also the support members 30 hold the coupler 102 in its place when the jaws 20 are forced with great force downward along the coupler 102 to obtain the tight grip.

A preferred detail of the support members 30 is that in the active position the contact surface with the shoulder 30 is located above the pivot axis 31, with the effect that any downward movement of the tubular 100 results in a tighter clamping of the shoulder by said support members 30.

The present invention also relates to a downhole tubular gripping and suspending apparatus adapted for gripping a downhole tubular and suspending said downhole tubular from said apparatus, said downhole tubular having a tubular pipe section of essentially uniform diameter and a top end of said tubular having a coupler for interconnecting tubulars, said top end of said tubular also having an exterior shoulder,

wherein said apparatus comprises:

a housing having a reception chamber with a bottom opening for introducing said top end of said tubular and a part of the tubular pipe section into the reception chamber via said bottom opening;

external tubular gripping means including:

• • a plurality of tubular gripping members mounted on said housing and adapted to grip the exterior of the tubular pipe section,
  • actuating means that allow displacement of said tubular gripping members between an inactive position, wherein said top end of said tubular can be introduced into said reception chamber, and an active position, wherein said tubular is gripped by said tubular gripping members;

shoulder support means including:

• • one or more shoulder support members mounted on said housing and adapted to engage beneath said shoulder of a tubular top end received in said reception chamber,
  • actuating means that allow displacement of said shoulder support members between an inactive position, wherein said top end of said tubular can be introduced into said reception chamber, and an active position, wherein each shoulder support members engages beneath said shoulder.

Claims

1-16. (canceled)

17. A downhole tubular gripping and suspending apparatus adapted for gripping a downhole tubular and suspending said downhole tubular from said apparatus, said tubular having a tubular pipe section of essentially uniform diameter and a top end of said tubular having a coupler for interconnecting tubulars, said coupler having an enlarged diameter part and said top end of said tubular also having an exterior shoulder,

wherein said apparatus comprises:

a housing having a reception chamber with at least a bottom opening for introducing said top end of said tubular into the reception chamber via said bottom opening;

external coupler gripping means including: one or more coupler gripping members moveable mounted on said housing and adapted to grip an exterior of the enlarged diameter part of the coupler of a tubular top end received in said reception chamber, actuating means that cause movement of said one or more coupler gripping members between an inactive position, allowing introduction of said top end of said tubular into said reception chamber, and an active position, wherein said coupler is gripped by said coupler gripping members;

shoulder support means including: one or more shoulder support members moveable mounted on said housing and adapted to engage under said shoulder of a tubular top end received in said reception chamber, actuating means that allow displacement of each shoulder support member between an inactive position, allowing introduction of said top end of said tubular into said reception chamber, and an active position, wherein each shoulder support member engages under said shoulder.

18. An apparatus according to claim 17, wherein multiple shoulder support members are provided, distributed about the reception chamber for the tubular top end, so as to engage under the shoulder at circumferentially spaced support locations.

19. An apparatus according to claim 17, wherein each shoulder support member is pivotable about an associated pivot axis between a raised inactive position and a lowered active position.

20. An apparatus according to claim 19, wherein the housing provides a stop for abutment of the shoulder support member in its active position, so that the force by the tubular on the shoulder support is directly transferred to the housing.

21. An apparatus according to claim 17, wherein multiple coupler gripping members are provided, distributed around the reception chamber for the tubular top end, so as to engage on the coupler at circumferentially spaced locations.

22. An apparatus according to claim 17, wherein a coupler gripping member is a clamping jaw, slidable along an associated guide of the housing.

23. An apparatus according to claim 22, wherein said guide forms a guide surface tapering to a reduced diameter in the direction of the bottom opening so that when the clamping jaw advances towards said bottom opening said clamping jaw moves into its active position and a clamping surface of said clamping jaw grips the coupler.

24. An apparatus according to claim 19, wherein the shoulder support members are each linked via an associated connector rod to a clamping jaw in order to achieve actuation of the shoulder support members through actuation of the clamping jaws.

25. An apparatus according to claim 24, wherein the shoulder support members are each linked via an associated connector rod to a clamping jaw such that first the shoulder support members reach their active position, where after the shoulder is brought to bear on these shoulder support members, and then the clamping jaws are brought into their active position.

26. An apparatus according to claim 22, wherein each clamping jaw is connected by an associated connecting rod to a common ring member which is slideable with respect to the housing.

27. An apparatus according to claim 26, wherein a power actuator is provided for the common ring member to move the common ring member towards a position corresponding to the inactive position of the clamping jaws, and wherein a spring is provided urging the common member towards a position corresponding to the active position of the clamping jaws.

28. An apparatus according to claim 17, wherein the apparatus includes a central shaft fitted to the housing, which central shaft is provided with a connector for connecting the central shaft to a motor of a top drive drilling mechanism.

29. An apparatus according to claim 28, wherein the central shaft is provided with a central fluid channel extending from an upper mouth to a fluid connector device extending in the reception chamber, said fluid connector device being adapted to connect to the tubular so as to establish a fluid connecting between said tubular and said central fluid channel.

30. An apparatus according to claim 29, wherein the fluid connector comprises a tube part connected to the housing and in communication with the central fluid channel, said tube part being insertable into the top end of the tubular, a sealing arrangement being provided for establishing a fluid seal between said tube part and the tubular top end.

31. An apparatus according to claim 30, wherein the sealing arrangement includes a sealing ring extending around the tube part and slideable with respect to said tube part along a sliding section thereof, while maintaining a fluid seal between said ring and said tube part, said ring being dimensioned to sealingly engage the top end of the tubular.

32. A downhole tubular gripping and suspending apparatus adapted for gripping a downhole tubular and suspending said downhole tubular from said apparatus, said downhole tubular having a tubular pipe section of essentially uniform diameter and a top end of said tubular having a coupler for interconnecting tubulars, said top end of said tubular also having an exterior shoulder,

wherein said apparatus comprises:

a housing having a reception chamber with a bottom opening for introducing said top end of said tubular and a part of the tubular pipe section into the reception chamber via said bottom opening;

external tubular gripping means including: a plurality of tubular gripping members mounted on said housing and adapted to grip the exterior of the tubular pipe section, actuating means that allow displacement of said tubular gripping members between an inactive position, wherein said top end of said tubular can be introduced into said reception chamber, and an active position, wherein said tubular is gripped by said tubular gripping members;

shoulder support means including: one or more shoulder support members mounted on said housing and adapted to engage beneath said shoulder of a tubular top end received in said reception chamber, actuating means that allow displacement of said shoulder support members between an inactive position, wherein said top end of said tubular can be introduced into said reception chamber, and an active position, wherein each shoulder support members engages beneath said shoulder.

33. A top drive mechanism including a body suspendable in a drilling rig for vertical movement, said top drive mechanism further including a motor having a rotatable output member, and further including an apparatus for gripping and suspending a downhole tubular as in claim 17, said apparatus being connected to said body so as to allow the vertical motion of a downhole tubular as well as rotary motion of the downhole tubular.

34. A drilling rig for use in oil and gas drilling including an apparatus for gripping and suspending a downhole tubular as in claim 17.

35. A method of drilling and/or servicing a well bore for oil and/or gas, wherein use is made of an apparatus for gripping and suspending a downhole tubular as in claim 17.

36. An apparatus according to claim 22, wherein the shoulder support members are each linked via an associated connector rod to a clamping jaw in order to achieve actuation of the shoulder support members through actuation of the clamping jaws.