NL2034271B1

NL2034271B1 - Hydraulic workover unit with tubular handling mechanism for positioning tubulars above a well head.

Info

Publication number: NL2034271B1
Application number: NL2034271A
Authority: NL
Inventors: Poort Björn
Original assignee: Ter Bron Groep B V
Priority date: 2023-03-06
Filing date: 2023-03-06
Publication date: 2024-09-18
Also published as: WO2024184396A1

Abstract

The invention relates to a hydraulic workover unit (2) configured for performing well operations, comprising a supporting structure (18) configured to be arranged above a well head (6); a tubular handling mechanism connected to the supporting structure (18) and configured for positioning a tubular (26) in an upright position above the well head (6), Wherein in the upright position the tubular (26) has an upper end (32) facing substantially upwards and a bottom end (28) facing substantially downwards; a jacking system (10) mounted to the supporting structure (18) and arranged below the tubular (26) when in the first position, wherein the jacking system (10) is configured for applying a load on the tubular (26) in at least an axial direction; wherein the tubular handling mechanism is rotatable around a substantially vertical first rotation axis (A); and wherein the tubular handling mechanism is rotatable over an obtuse angle from a first position in which the tubular handling mechanism holds the tubular (26) in the upright position to a second position, and vice versa, around a second rotation axis (B) that is perpendicular to the first rotation axis (A).

Description

P36183NLO0/MOV

Title: Hydraulic workover unit with tubular handling mechanism for positioning tubulars above a well head.

FIELD OF THE INVENTION

The present invention relates to a tubular handling mechanism for a hydraulic workover unit configured for performing well operations, in particular to a tubular handling mechanism for a snubbing unit.

BACKGROUND OF THE INVENTION

Hydraulic workover units are widely used for well maintenance and interventions, such as running and retrieving pipes to perform fishing, milling, pumping or any other downhole operation. These units may reach heights up to 10 metres, or even more, dependent on the cavity which is required for staging in bottom hole assemblies during operations. In the case of live well operations, wherein the well is still pressurized, the hydraulic workover unit is a snubbing unit comprising blowout-preventers, thus increasing the size of the unit even more: snubbing units may reach up to 15 metres or higher. In conventional hydraulic workover units, the unit is placed over a well and pipes are hoisted to the top of a hydraulic workover unit, where a working platform is arranged. The operating personnel on the working platform must then manoeuvre and guide the hoisted pipes above the pipes already present, after which the pipes are connected and forced into the well by a jack. Hoisting of the pipes to the top of the hydraulic workover unit is performed by an external crane, a gin pole counterbalance winch system (including guywires and deadweights for wind loads) or a derrick. During operations, these hoisting systems grab a pipe which is stored on ground level by its upper end and hoist the tubular upwards until the bottom end of the tubular has reached workers on a working platform on top of the hydraulic workover unit, and vice versa.

These conventional systems thus require operators to work on top of a possibly pressurized well, on a small working platform surrounded by heavy moving machinery, high pressure hoses and possibly underneath a load. Generally, three workers are required on the working platform during standard operations. In case of a blowout during live well operations, even with emergency egress systems, operators are put in harm’s way. In addition, these external cranes or gin pole counterbalance winch systems are required to be at least the height of the tubular length on top of the hydraulic workover unit, which may amount to well over 20 metres. The enormous size and weight of the machinery that is required during operations can be a major disadvantage, especially during operations in relatively tight spaces such as small satellite platforms.

There are some alternative ways known in the art of drilling to supply rods to a drilling head. US2010/0021721A1 for example relates to an accessory for a drill rig used in drilling bore holes. The drill rig has an upstanding mast to which a support member is connected. Handling means supply drilling rods in a horizontal position from a storage zone to the support member, which support member rotates the rod to a vertical position above the drill string, after which the rod is engaged by a drive head which enables the rod to be engaged with a drill string that is located in the bottom of the mast. As such, there is no crewmember needed to manipulate and support the drill rod in its movement between the storage zone and the drill string.

Unfortunately, a system according to US2010/0021271A1 is impractical for use for hydraulic workover unit or snubbing units. The handling means are required to provide the drilling rods from the storage zone in a horizontal position. In the case of hydraulic workover unit or snubbing units, which can reach up to 10 or 20 metres heigh, the storage zone would be required to be positioned at such heights as well, which would require large and heavy equipment and the use of a derrick.

WO02016/167632 discloses another rod mounting device for a drilling machine which supplies the drill rod in a horizontal position to a rod clamp unit. The rod clamp unit rotates the drill rod to a vertical position, after which the drill rod is grabbed by a drill head. Supply of the drill rod is achieved by a rod supply unit, which elevates a rod in a horizontal state from where it is supplied to the rod clamp.

Similarly as to US2010/0021271A1, a system according to W02016/167632 cannot be used for hydraulic workover unit or snubbing units: the rod supply unit would have to elevate the rods up to 20 metres high, which would require additional heavy equipment.

DESCRIPTION OF THE INVENTION

The present invention aims to overcome the above disadvantages at least partly or to provide a usable alternative. In particular, the present invention aims to provide a hydraulic workover unit which comprises more compact equipment for hoisting tubulars.

Another object of the present invention is to provide a hydraulic workover unit which can be operated with less manual effort.

In a first aspect, the present invention provides a hydraulic workover unit configured for performing well operations, comprising a supporting structure configured to be arranged above a well head; a tubular handling mechanism connected to the supporting structure (and configured for positioning a tubular in an upright position above the well head, wherein in the upright position the tubular has an upper end facing substantially upwards and a bottom end facing substantially downwards, a jacking system mounted to the supporting structure and arranged below the tubular when in the first position, wherein the jacking system is configured for applying a load on the tubular in at least an axial direction; wherein the tubular handling mechanism is rotatable around a substantially vertical first rotation axis, and wherein the tubular handling mechanism is rotatable over an obtuse angle from a first position in which the tubular handling mechanism holds the tubular in the upright position to a second position, and vice versa, around a second rotation axis that is perpendicular to the first rotation axis.

The hydraulic workover unit according to the invention may be used for dead well operations, or it may be converted to a snubbing unit by including extra blowout preventers to perform live well operations. The hydraulic workover unit comprises a supporting structure configured to be arranged above the well head. The supporting structure is for example an externally prepared structure resting on the earth around the well head to support the hydraulic workover unit, a blowout-preventer or a jacking system structure when the hydraulic workover unit is solely supported by the well head. Connected to the supporting structure is a tubular handling mechanism, which is configured for positioning a tubular in an upright position above the well head, such that the tubular has an upper end facing substantially upwards and a bottom end facing substantially downwards. In this upright position, the tubular is positioned above a jacking system which is also arranged above the well head. This jacking system is preferably hydraulically driven, or alternatively pneumatically or electrically driven, and is configured for applying a load on the tubular in at least the axial direction of the tubular, to force the tubular into the well head or to retrieve the tubular from the well. In addition, the jacking system may also be configured for providing a torsional load on tubulars. Hence, in the case of threaded tubulars the jacking system may also be configured for rotating, and thereby tightening or loosening tubulars.

The tubular handling mechanism according to the invention is rotatable around a first axis that is substantially vertical. This allows the tubular handling mechanism to easily grab tubulars (or other materials) in a wide range around the hydraulic workover unit. The tubular handling mechanism may preferably rotate fully around the first axis, i.e. up to 360°. As such the tubular handling mechanism may grab tubulars (or other materials) around the full perimeter of the hydraulic workover unit. Alternatively, to prevent interference with the components of the hydraulic workover unit, the tubular handling mechanism may also for example rotate up to 180° about the first rotation axis. To drive the tubular handling mechanism in rotation, known rotational drive mechanisms may be used, such as a hydraulic or electrical slew drive.

The tubular handling mechanism is furthermore rotatable around a second rotation axis that is substantially perpendicular to the first rotation axis. The second rotation axis is thus substantially horizontal. The tubular handling mechanism may be rotated around the second rotation axis from a first position to a second position over an obtuse angle, e.g. over an angle of atleast 100° preferably at least 110°, and more preferably at least 120° from the second position to the first position. The rotating angle may depend on the height of the hydraulic workover unit. For example, in the case of smaller hydraulic workover units, a lower rotating angle in the range of 100-130°, such as 110-120°, may be favored. In the case of larger hydraulic workover units, such as snubbing units, a rotating angle in the range of 120-170°, such as 130-160°, may be favored. The rotation angle is preferably maximally 175°. The tubular handling mechanism may also be rotated in the opposite direction, i.e. from the second position to the first position. When the tubular handling mechanism is rotated, the bottom end of the tubular faces the hydraulic workover unit.

The rotation of the tubular handling mechanism over the obtuse angle enables efficient supply of the tubulars from a low height, such as from ground level, to the height where the tubular is eventually required during well operations. The top of the pipe thus does not have to be lifted to above the top of the hydraulic workover unit by a crane or gin pole as done in conventional systems, which systems therefore are required to be at least the height of the hydraulic workover unit plus the tubular. The rotation of the tubular handling mechanism over the obtuse angle thus advantageously eliminates the need for large, high and heavy equipment such as cranes, gin poles or horizontal tubing lifting machinery. The whole system and value chain of operations therefore becomes more compact, simpler, and safer.

Moreover, assembly of the hydraulic workover unit with a tubular handling mechanism according to the invention is more convenient. Large and heavy cranes (which need to be recertified regularly) are required during the assembly phase of conventional hydraulic workover units, especially for installing e.g. the gin pole counterbalance system. After assembly of the hydraulic workover unit these cranes are either not used or dismantled. As the overall height of a hydraulic workover unit with a tubular handling mechanism according to the invention is less, the hydraulic workover does not require the use of these larger cranes during assembly and installation. This is especially advantageous for offshore operations where cranes are not always present or are limited in capacity, and also provides advantages in terms of sustainability as no less heavy machinery is required to be transported to the platforms.

In addition, the tubular handling mechanism has the advantage that, after rotating, the tubular is immediately in or close to the upright position. It may only be required to perform a translational or rotational movement of the tubular after rotating, to ensure that the tubular is in the correct upright position above the well head. These movements are preferably automated. The need for operators who manually position the tubular in the correct position is thereby eliminated. A hydraulic workover unit with a tubular handling mechanism according to the invention therefore requires less or no more operators to be present on the working platform. This is especially advantageous during operations on small satellite platforms, where a restriction on the maximum number of persons on board (POB) is in place and deck space is limited, which may provide a bottleneck to the speed and efficiency of operations.

The tubular handling mechanism can also advantageously be used for the removal of cut or severed cemented casings. In conventional systems, these old pieces of tube retrieved from wells are heavy and have no lifting points. It is therefore required to mill holes in them after they have been pulled out of the well, and a hoisting device is placed in these holes to bring it from the well to ground level. The hydraulic workover unit with tubular handling mechanism according to the invention is instead configured for engaging the tubular, which eliminates the need for milling holes. Moreover, the tubular handling mechanism may be used for wire-line or slick-line activities in the well.

An additional advantage of the hydraulic workover unit according to the invention is that the handling of a wash pipe may be more convenient. A wash pipe may be used to recover a stuck pipe, debris or lost equipment. In conventional constructions, the handling of the washier pipe requires additional operations: a tubular which is held by the gin pole or the external crane should be lowered, the wash pipe should be picked up and transported back and from the workover unit. It is furthermore required to attach and re-attach the pump hose and hydraulically actuated well control valve, and the connection must be pressure tested each time. The tubular handling mechanism according to the invention in contrast may be used to pick up the wash pipe when it is stored on the hydraulic workover unit, e.g. in a wash pipe storage space, such as a mousehole. The wash pipe storage space is preferably mounted to the hydraulic workover unit. The pump hose and well control valves are preferably attached to the wash pipe when it is stored. As the tubular handling mechanism is rotatable around the first rotation axis, the tubular handling mechanism may be used to pick the wash pipe from the wash pipe storage space, displace the wash pipe to the required position above the well head, and afterwards put the wash pipe back in the storage space. The tubular handling mechanism may optionally comprise well control apparatus configured for automatically closing tubulars in the case of blowouts. A well control apparatus is for example a hydraulic feature, such a hydraulic well control valve, e.g. a full opening safety valve, a stabbing valve or an inside blowout preventer, with which a tubular can be closed from a distance. In conventional systems, these valves are closed manually by operators present on the working platform, which puts them at great risk of harmful accidents.

In an embodiment of the invention, the tubular handling mechanism comprises engaging means configured for engaging the tubular, such as one or more clamping devices or one or more grippers. The engaging means may be configured for engaging the tubular when in an inclined position, e.g. with a bottom end upwards relative to a horizontal plane, or when in a horizontal or vertical position. The engaging means may engage the tubular when it is positioned at a low height, e.g. when positioned in a storage space near ground level, or whenitis provided by a tubular supply unit, such as a telescopic handler or a truck mounted crane.

The engaging means are optionally rotatable around a third rotation axis that is substantially perpendicular to the longitudinal axis of the tubular handling mechanism for rotating the tubular around said axis. The tubular may for example be rotated around the third rotation axis from a position substantially parallel to the longitudinal axis of the tubular handling mechanism to the upright position, or from a horizontal or vertical position to a position substantially parallel to the longitudinal axis of the tubular handling mechanism.

Additionally or alternatively, the engaging means are rotatably mounted to the tubular handling mechanism, such that the engaging means are rotable around a fourth rotation axis that is substantially parallel to the longitudinal axis of the jib arm.

Additionally or alternatively, the engaging means comprises an extension mechanism to enable a translation movement of the tubular with respect to the tubular handling mechanism. The engaging means may for example be extendable by means of a scissor mechanism to translate the tubular such that the tubular is moved from the rotated position to the upright position, or vice versa.

In an embodiment of the invention, the engaging means are configured for engaging at least two tubulars and/or for engaging at least a tubular and a well control apparatus, or for engaging at least three objects, such as two tubulars and a well control apparatus. The engaging means are preferably two grippers rotatably mounted opposite of each other to the jib arm. The engaging means may for example be configured for engaging a regular pipe and a wash pipe which is used to recover a stuck pipe, debris or lost equipment. In conventional constructions, where only one tubular is lifted to or from the hydraulic workover unit, the handling of the washier pipe requires additional operations: a tubular which is held by the gin pole or the external crane should be lowered, the wash pipe should be picked up and transported back and from the workover unit, and the tubular should afterwards be picked up and transported. It is furthermore required to attach and re-attach the pump hose and hydraulically actuated well control valve, and the connection must be pressure tested each time. When the hydraulic workover unit instead comprises a jib arm with rotatably mounted engaging means configured for engaging at least two tubulars, the wash pipe may be present on the jib arm at all times. To transport the wash pipe to the top of the hydraulic workover unit therefore only requires rotation of the engaging means. Additionally or alternatively to the wash pipe, the engaging means may engage a well control apparatus configured for closing off the well in the case of a blowout without the requirement of manual operations. Such a well control apparatus is for example a valve which may be hydraulically driven, e.g. a full opening safety valve, a stabbing valve or an inside blowout preventer. Such a well control feature is preferably present on the wash pipe. The well control apparatus comprises for example a stabbing valve which is controlled via suitable control lines and which is positioned on top of the wash pipe. The valve is via a pump inlet connected a pump hose. In the case of a blowout, the rotatable engaging means are rotated to position the wash pipe above the well head, after which the valve can be closes from a distance via the suitable control lines. The engaging means, such as clamps are then preferably configured for carrying heavy loads.

In an embodiment of the invention, the tubular handling mechanism is extendable in a longitudinal direction of the tubular handling mechanism, e.g. by a telescopic extension mechanism. This advantageously makes the tubular handling mechanism more versatile and allows the tubular handling mechanism to reach tubulars and other materials that are further away from the hydraulic workover unit.

In a preferred embodiment of the invention, the tubular handling mechanism comprises a jib arm which comprises a first end that is rotatably mounted to the supporting structure and asecond end. The jib arm is a relatively small apparatus which requires minimal space on the hydraulic workover unit, while also being able to rotate the tubular around the second rotation axis over a wide angle to easily move the tubular to the top of the hydraulic workover unit.

The range over which the jib arm is rotatable is preferably preset at a fixed range such that the movement of the jib arm is automated, and the first and second position are fixed. In the first position, the second end of the jib arm is pointing substantially upwards, and in the second position the second end of the jib arm is pointing relatively downwards.

It is preferred that the engaging means are provided at substantially the second end of the jib arm, to ensure that the tubular handling mechanism may easily grab tubulars from low heights, e.g. from ground level,

The jib arm may also advantageously be used to install wireline or coiled tubing which are for example used to determine the condition/integrity of the cement behind the casings in dismantling processes, or any other intervention, such as plug setting, logging or perforating.

In conventional hydraulic workover units, a separate crane is required for installing the wireline or coiled tubing, and when having a gin pole present, it should be moved away as it forms an obstruction. The jib arm, on the other hand, is an efficient and compact alternative that eliminates these disadvantages.

The jib arm is preferably a fly jib configured for rotating over an angle of up to 210° to provide a compact configuration usable e.g. during transportation. The fly jib may even be stored within the hydraulic workover unit itself during transportation. The fly jib arm comprises a jib arm base with which the jib arm is mounted to the jacking structure. The jib arm is with the first end rotatably mounted to the jib arm base and has a second free end. For rotating over an angle of up to 210° the jib arm comprises a cylinder which has a fulcrum at which two lever members are engaged, wherein a first lever member also engages the first end of the jib arm and a second lever member also engages the jib arm base. When the cylinder extends, the lever members are moved and the jib arm is thereby rotated around the second rotation axis.

In a preferred embodiment of the invention, the jacking system of the hydraulic workover unit comprises a pipe makeup (and breakout) assembly, such as a tong assembly or a bucking unit, configured for connecting and disconnecting tubulars. The assembly can be chosen from known device and preferably comprises at least a tong member, such as a backup tong, for engaging the tubular and a torque member, such as a rotary table or a power tong, for applying a torsional load on the tubular. The torque member is often driven by known rotational drive mechanisms, such as a hydraulic or electrical slew drive. The pipe makeup and breakout assembly is preferably arranged within the jacking system, such as at least a part of the pipe makeup and breakout assembly being arranged between a stationary and a traveling slip of the jacking system. Advantageously, the use of such an integrated pipe makeup and breakout assembly eliminates the need for an operator who manually attaches an external tong to the tubulars for threading. The assembly, in particular the tong member, preferably comprises a compensation system, e.g. of a spring type, which enables the tubular to be moved slightly upwards or downwards during the threading of the tubular with a bottom tubular.

In an embodiment of the invention, the torque member of the pipe makeup assembly is formed by the traveling slip of the jacking system. The traveling slip may then be configured for applying both an axial load as week as a torsional load on the tubular. Thus advantageously, no separate torque member is required to rotate the tubular. This advantageously reduces the costs of the machinery. The backup tong is preferably arranged between the stationary and the traveling slip.

In a second aspect, the present invention relates to a hydraulic workover unit configured for performing well operations, comprising a supporting structure configured to be arranged above a well head a tubular handling mechanism connected to the supporting structure and configured for positioning a tubular in a upright position above the well head, wherein in the upright position the tubular has an upper end facing substantially upwards and a bottom end facing substantially downwards, a jacking system mounted to the supporting structure and arranged below the tubular when in the upright position, wherein the jacking system is configured for applying a load on the tubular in at least an axial direction; wherein the tubular handling mechanism is configured for engaging the tubular in a substantially horizontal or vertical position, and wherein the tubular handling mechanism is rotatable over an obtuse angle from a first position in which the tubular handling mechanism holds the tubular in the upright position to a second position, and vice versa, around a substantially horizontal rotation axis.

The tubular handling mechanism of the hydraulic workover unit of the second aspect of the invention may be rotatable for example over an angle of at least 100°, preferably at least 110°, and more preferably at least 120° from the second position to the first position.

The rotating of the tubular handling mechanism over an obtuse angle enables efficient supply of the tubulars from a low height, such as from ground level to the height where the tubular is eventually required during well operations. The tubular handling mechanism may further be rotatable around a substantially vertical rotation axis. This allows the tubular handling mechanism to easily grab tubulars (or other materials) in a wide range around the hydraulic workover unit. To prevent interference with the components of the hydraulic workover unit, the tubular handling mechanism may for example rotate up to 180° about the first rotation axis. To drive the tubular handling mechanism in rotation, known rotational drive mechanisms may be used, such as a hydraulic or electrical slew drive.

The tubular handling mechanism, such as a jib arm, preferably comprises engaging means configured for engaging the tubular. These engaging means are preferably rotatable around a rotation axis substantially perpendicular to a longitudinal axis of the tubular handling mechanism.

The various embodiments of the hydraulic workover unit according to the first aspect of the invention, described above, are similarly applicable to the hydraulic workover unit according to the second aspect of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention shall now be explained in more detail below by means of describing some exemplary embodiments in a non-limiting way with reference to the accompanying drawings, in which:

Fig. 1 shows an embodiment of a snubbing unit with a jib arm according to the invention;

Fig. 2 shows a sequence of moving a tubular to an upright position with a snubbing unit with a jib arm according to the invention;

Fig. 3 depicts an embodiment of a snubbing unit with a jib arm according to the invention;

Fig. 4 depicts a hydraulic workover unit with a fly jib according to the invention;

Fig. 5 depicts an embodiment of a jacking system with a tong assembly on a hydraulic workover unit according to the invention;

Fig. 6 depicts a jib arm with rotatable engaging means on a hydraulic workover unit according to the invention;

DETAILED DESCRIPTION OF THE DRAWINGS

In fig. 1 the hydraulic workover unit, in this embodiment a snubbing unit, is in its entirety denoted with reference number 2. The snubbing unit comprises a stack of blowout-preventers 4 which are positioned above a well head 8, with an annular blowout-preventer 8 positioned at the top of the stack 4. The height of the blowout-preventers 4 is dependent on the amount of cavity which is required during operations, and for snubbing units may amount up to 10 or 15 meters. A jacking system 10 configured for applying at least an axial on a tubular is mounted on top of the blowout-preventers 4. The jacking system 10 comprises a jacking structure 12, a stationary slip 14 and a traveling slip 16 which are hydraulically driven using hydraulic cylinders 17 when forcing a tubular in the well head 6 or when retrieving a tubular. A supporting structure 18 further supports the hydraulic workover unit 2.

Mounted to the jacking structure 12 is a tubular handling mechanism, in this embodiment a jib arm 20. The jib arm 20 extends between a first end 22 that is rotatably mounted to the hydraulic workover unit and a second end 23. To rotate around the first rotation axis A, the jib arm 20 is rotatably connected to a column24 that is present on the hydraulic workover unit. A drive, such as a slew drive, is used for driving the jib arm in rotation around the first rotation axis

A

The jib arm may furthermore rotate over an obtuse angle a around a second rotation axis

B that is perpendicular to the first rotation axis A. The jib arm 20 may rotate from a first position in which the jib arm holds the tubular 26 in the upright position to a second position, and vice versa. When a snubbing unit 2 is used for operations, the angle over which the tubular 26 is rotated is preferably up to 140° or even 150°.

The jib arm 20 is also configured for the reverse movement: after the jacking system 10 has retrieved a tubular 26 from the well, the jib arm 20 engages the tubular 26 in the upright position, after which the jib arm 20 is rotated to the supply configuration, from where it can be taken over by the supply unit (not shown).

The tubular is positioned on ground level, in this embodiment in a horizontal position in a storage space. At the second end 23 of the jib arm 20, engaging means 27 are provided which are configured for engaging a tubular 26. When engaging the tubular 26, the tubular may be in e.g. a horizontal position, a vertical position or in an inclined position. The engaging means 25 are rotatable around a third rotation axis C which is substantially perpendicular to a longitudinal axis of the jib arm 20, such that the tubular 26 may e.g. be rotated from the horizontal position to a position substantially parallel to the longitudinal axis of the jib arm 20.

An optional sequence of steps in which the jib arm 20 rotates over an angle a to position the tubular 26 in the upright position is shown in fig. 2. In fig. 2A, the jib arm 20 engages a tubular 26 from a storage space. The jib arm 20 is in its second position in which the second end 230f the jib arm is pointing relatively downwards such that the engaging means 25 can engage the tubular 26. The jib arm 20 is then optionally retracted and partially rotated around the second rotation axis B (fig. 2B) and/or alternatively the engaging means partially rotate the tubular around the third rotation axis C while the jib arm 20 rotates around the second rotation axis B (fig. 2B). The engaging means 27 then rotate the tubular 26 around the third rotation axis

C for positioning the tubular parallel to the jib arm (fig. 2D). The jib arm may then be rotated to its first position (2E). To position the tubular in the upright position, the jib arm rotates around the first rotation axis A (2F). Alternatively, the engaging means may rotate around a fourth rotation axis D that is substantially parallel to the jib arm for positioning the tubular in the upright position.

Optionally, a final translational or rotational movement of the tubular 26 may be required after bringing the jib arm 20 to its first position to ensure that the tubular 26 is in the correct upright position above the well head 6. When the tubular 26 is in this upright position, the traveling slip 16 of the jacking system 10 moves upwards and engages the tubular 26 and the tubular 26 is ready to be connected to a bottom tubular (not shown). Alternatively, the jib arm 20 may also retract to lower the tubular 26 after which the tubular 26 is engaged by the jacking system 10.

Fig. 3 shows another embodiment of a hydraulic workover unit according to the invention. The jib arm 20 is rotatably mounted to the jacking structure 12 and is rotatable over an obtuse angle from a first position in which the jib arm 20 holds the tubular 26 in the upright position to a second position, and vice versa, around a substantially horizontal rotation axis B.

The jib arm furthermore comprises rotatable engaging means 27 that may rotate around a rotation axis D that is substantially parallel to the longitudinal axis of the jib arm 20 and/or that may rotate the tubular 26 around a rotation axis C which is substantially perpendicular to a longitudinal axis of the jib arm 20The engaging means may engage a tubular 26 that is substantially horizontal or vertical, e.g. from a storage space near ground level or from a fingerboard

Fig. 4 shows a jacking system 10 with a jib arm 20 in a transportation configuration during transportation of the hydraulic workover unit 2 to or from an operation site. The jib arm 20 comprises a jib arm base 40 with which the jib arm 20 is mounted to the jacking structure 12. The jib arm 20 is with the first end 22 rotatably mounted to the jib arm base 40 and has a second free end 23 which extendible in the longitudinal direction of the jib arm 20 by a telescopic extension mechanism 42. The jib arm 20 comprises a cylinder 44 with which the jib arm 20 is rotated around the second rotation axis B. The cylinder 44 has a fulcrum 45 at which two lever members 46, 47 are engaged, wherein a first lever member 46 also engages the first end 22 of the jib arm 20 and a second lever 47 member also engages the jib arm base 40. When the cylinder 44 extends, the lever members 46, 47 are moved and the jib arm as thereby rotated around the second rotation axis B, enabling the jib arm 20 to rotate over an angle of up to 210°. Due to this large rotating range the jib arm 20 can be stored compactly in the hydraulic workover unit 2 during transport.

Fig. 5 shows a detailed version of the mechanism for providing a torsional load on the tubular 26 as depicted in Fig. 1. The backup tong 34 is positioned within the jacking structure, and specifically below the traveling slip 16. The backup tong 34 is configured for rotating the tubular 26 around the longitudinal axis of the tubular 26. As such, that the tubular 26 may be connected to or disconnected from a bottom tubular. The backup tong 34 is driven by a rotational drive mechanism 36, such as a hydraulic or electrical slew drive, which is in this embodiment positioned below the traveling slip 16 of the jacking system 10. The backup tong 34 comprises a compensation system, e.g. of a spring type, which enables the tubular 26 to be rotated and simultaneously to be moved slightly upwards or downwards during the threading of the tubular 26 with a bottom tubular (not shown).

Fig. 6 shows a jib arm 20 having rotatable engaging means 27 which are rotatable around the fourth rotation axis D. The rotatable engaging means 30 in this embodiment consist of two grippers 50, 52 which are rotatably mounted opposite of each other to the jib arm 20. Each gripper 50, 52 is configured for engaging a tubular 26, such as a general pipe and a wash pipe 54. The wash pipe 54 may therefore be present on the jib arm 20 at all times.

Instead of picking up and transporting the wash pipe 54 to the hydraulic workover unit 2 when required, the rotatable engaging means 30 are rotated and the wash pipe 54 is in position.

The wash pipe 54 preferably also comprises a well control apparatus 56 which is shown in more detail in the figure.

The well control apparatus 56 comprises of a valve 58,

preferably a hydraulic valve such as a stabbing valve, which is controlled via suitable control lines 60 and which is positioned on top of the wash pipe 58. The valve 58 is via a pump inlet 62 connected a pump hose 63. In the case of a blowout, the rotatable engaging means are rotated to position the wash pipe 54 above the well head and to close the valve 58 from a distance via the suitable control lines 60. This eliminates the need for manual closing of the well during a blowout and greatly increases the safety of the operators.

Claims

CONCLUSIONS

1. A hydraulic overwork unit (2) configured for performing wellbore operations, comprising a support structure (18) configured to be positioned above a wellhead (6); a tubular handling mechanism connected to the support structure (18) and configured to position a tubular (26) in an upright position above the wellhead (6), the tubular (26) in the upright position having an upper end (32) directed substantially upward and a lower end (28) directed substantially downward; a jacking system (10) mounted to the support structure (18) and disposed below the tubular (26) in the first position, the jacking system (10) configured to exert a force on the tubular (26) in at least an axial direction; the tubular handling mechanism being rotatable about a substantially vertical first rotational axis (A); and wherein the tube handling mechanism is rotatable through an obtuse angle from a first position in which the tube handling mechanism holds the tube (26) in the upright position, to a second position, and vice versa, about a second axis of rotation (B) perpendicular to the first axis of rotation (A).

2. Hydraulic overwork unit (2) according to claim 1, wherein the tube handling mechanism is rotatable through an angle of at least 100°, preferably at least 110°, and preferably at least 120°, from the second position to the first position, and vice versa, about the second rotation axis (B).

3. A hydraulic overwork unit (2) as claimed in claim 1 or 2, wherein the tube handling mechanism (20) comprises gripping means (27) configured to grip the tube (26), and wherein the means (27) are rotatable about a third axis of rotation (C) substantially perpendicular to a longitudinal axis of the tube handling mechanism.

4. Hydraulic overwork unit (2) according to any one of the preceding claims, wherein the gripping means are rotatable about a fourth axis of rotation (D) which is substantially parallel to the longitudinal axis of the tube handling mechanism.

5. A hydraulic overwork unit (2) as claimed in claim 3 or 4, wherein the gripping means (27) are configured to hold at least two pipes (26) and/or at least one pipe (26) and a well control device (56).

86. Hydraulic overwork unit (2) according to any of the preceding claims, wherein the jacking system (10) comprises a pipe tightening device that applies a torsional load to the pipe (26) for connecting or disconnecting pipes.

The hydraulic overwork unit (2) of claim 6, wherein the tube fixing device comprises a coupling member configured to rotate the tube (26), the coupling member being formed by a displacement plate (16) of the jacking system (10) configured to apply an axial and a torsional load to the tube (26).

8. Hydraulic overwork unit (2) according to claim 7, wherein the tube fastening device comprises a fastening pliers, and wherein the fastening pliers are positioned under the displacement plate (16) of the jacking system (10).

9. Hydraulic overwork unit (2) according to any of the preceding claims, wherein the tube handling mechanism is extendable in the longitudinal direction of the tube handling mechanism.

10. Hydraulic overwork unit (2) according to any one of the preceding claims, wherein the tube handling mechanism comprises a swing arm (20) extending between a first end pivotally attached to the support structure (18) about the second rotation axis (B), and a second end (23).

11. Hydraulic overwork unit (2) according to claim 10, wherein the gripping means (27) are arranged at the second end (23) of the swing arm.

12. Hydraulic overwork unit (2) according to any of the preceding claims, further comprising a wash tube storage space, the wash tube storage space preferably being attached to the hydraulic overwork unit.

13. Hydraulic overwork unit (2) according to any of the preceding claims, wherein the hydraulic overwork unit (2) is a snubbing unit with blowout prevention systems (4) positioned above the wellhead (6) and below the jacking system (10).

14. A hydraulic overwork unit (2) configured for performing wellbore operations, comprising a support structure (18) configured to be positioned above a wellhead (6); a tubular handling mechanism connected to the support structure (18) and configured to position a tubular (26) in an upright position above the wellhead (6), the tubular (26) in the upright position having an upper end (32) directed substantially upward and a lower end (28) directed substantially downward; a jacking system (10) mounted to the support structure (18) and disposed below the tubular (26) when positioned in the upright position, the jacking system (10) configured to exert a force on the tubular (26) in at least an axial direction; the tubular handling mechanism being configured to retain the tubular (26) in a substantially horizontal or vertical position; and wherein the tube handling mechanism rotates through an obtuse angle from a first position, wherein the tube handling mechanism holds the tube (26) in the upright position, to a second position, and vice versa, about a substantially horizontal axis of rotation.

15. Hydraulic overwork unit (2) according to claim 14, wherein the tube handling mechanism is rotatable through an angle of at least 100°, preferably at least 110°, and preferably at least 120°, from the second position to the first position, and vice versa.

16. A hydraulic overwork unit (2) as claimed in claim 14 or 15, wherein the tube handling mechanism (20) comprises gripping means (27) configured to grip the tube (26), and wherein the gripping means (27) are rotatable about a rotational axis substantially perpendicular to a longitudinal axis of the tube handling mechanism.

17. Hydraulic work according to any of the preceding claims 14-16, wherein the gripping means are rotatable about a fourth axis of rotation (D) which is substantially parallel to the longitudinal axis of the tube handling mechanism.