Patent Application
20130341001
The present invention is directed to the field of oil and gas drilling and well servicing operations, and in particular to mobile coiled tubing rigs used in oil and gas drilling and well servicing operations.
Coiled tubing is a continuous string of steel tubing that is rolled onto a spool, and is used for a wide range of oil field services, including but not limited to drilling, logging, cleanouts, fracturing, cementing, underreaming, fishing, completion and production.
To facilitate coil tubing operations, mobile coiled tubing units, or rigs as they are also known, have been developed that can be easily transported to and from the relevant well site. The rigs comprise certain conventional elements, namely: a wheeled platform or frame forming the base of the rig, a reel to store and dispense the coil tubing string as needed, an injector head that is used to insert and retract the coiled tubing string from the well bore, some form of mast or hoist to elevate the injector above the well head, a control center for the operator, a power source for system power. In many, instances, to facilitate ease of transport, the unit comprises a tandem/tri-drive truck and dedicated coil rig chassis such as a flat bed trailer.
Existing mobile coiled tubing rigs having certain limitations. The various elements comprising the unit, in particular the spool of coiled tubing, are extremely heavy and if they not balanced correctly with respect to each other then the stability of the mobile platform during transport can be greatly impaired. Such instability can compromise the safe handling of the rig, especially during highway driving conditions. Further, on existing mobile coiled tubing rigs the various elements are in fixed positions dictated by the need to have certain required spacing between the coil and the injector during the performance of the down hole work. This fixed positioning of the various elements greatly impairs the mobility of the rig because the weight distribution in uneven and suboptimal to balanced transport and often results in certain axle grouping arising that is over the allowed weight.
Rough and uneven terrain also poses a challenge to existing mobile units. In particular, the limited clearance between the ground and the bottom of the coiled tubing spool often restricts the ability of the mobile unit to traverse uneven ground. This can be problematic given the remote nature of a great many well sites.
Another limitation of existing mobile units is the limit placed on mast size. The physical size of the mobile platform that the elements are mounted on are strictly regulated by transportation laws, and this coupled with the need to promote stability in accordance with all applicable transportation regulations, dictates the maximum mast length that can be used. This frequently results in the use of a mast length that is shorter than the optimal length for coiled tubing operations.
A further limitation of existing mobile coiled tubing units is the difficulty in aligning the injector and lubricators with the well head. Limited movement of the mast results in the need to repeatedly move the entire apparatus using the tractor until alignment is achieved. Movement of the entire apparatus with a tractor is time consuming and difficult. As a result, coiled tubing operations are frequently conducted without optimal alignment which poses obvious safety risks. Existing mobile units also have limited capacity to readily maintain the alignment of the injector with the well head following the addition and removal of lubricators which alters the relative height and alignment of the injector to the well head.
A further limitation faced by operators of existing mobile coiled tubing units arises by virtue of transportation and hauling regulations and rules that differ across various jurisdictions. In particular, each jurisdiction has particular weight and balance guidelines for trailers and as such, while a mobile unit may comply in one province, state or territory, it may not comply in another. This is problematic during long haul transportations, or if the well site straddles the boundary between two jurisdictions. Currently, with certain prior art mobile coiled tubing rigs, the reel has to actually be removed and transported separately because of non-conformity with the relevant transportation rules and regulations.
What is needed is a mobile coiled tubing rig that mitigates at least some of the limitations of the prior art.
In one aspect, the invention may comprise a mobile coiled tubing rig comprising:
In one embodiment, the mast assembly may comprise a mast base which is moveable longitudinally along the frame. The mast assembly may also comprise a mast sleeve within which the mast may telescopically extend or retract. The rig may further comprising a plurality of retractable support jack assembly, each support jack assembly comprising a support jack and a telescoping horizontal cylinders affixed to the frame, the support jack assemblies being moveable between a horizontal storage position and a deployed position wherein the support jacks engage the ground beneath the frame, and wherein the telescoping horizontal cylinders may be used to actuate lateral movement of the frame relative the support jacks when in the deployed position.
In one embodiment, the reel assembly may comprise a vertical lift mechanism comprising a horizontal pivot and a hydraulic cylinder to pivotably lift or lower the reel assembly. The reel assembly may be mounted to a slide track on the frame, and is pushed or pulled along the slide track by a hydraulic cylinder. The reel assembly may comprises a reel drive comprising a rack and pinion drive driven by a closed-loop hydraulic motor.
In one embodiment, the mast assembly may comprise a pair of mast sleeves and a pair of parallel masts, interconnected by at least one cross member, wherein one end of the at least one cross member is pivotably attached to one mast and the other end is removably latched to the other mast.
In another aspect, the invention may comprise a mobile coiled tubing rig comprising:
In one embodiment, the mast assembly may comprise a mast sleeve within which the mast may telescopically extend or retract. The reel assembly may be movable longitudinally along the frame, and vertically in relation to the frame.
In the drawings, like elements are assigned like reference numerals. The drawings are not necessarily to scale, with the emphasis instead placed upon the principles of the present invention. Additionally, each of the embodiments depicted are but one of a number of possible arrangements utilizing the fundamental concepts of the present invention. The drawings are briefly described as follows:
The invention relates to a mobile coiled tubing unit. When describing the present invention, all terms not defined herein have their common art-recognized meanings. To the extent that the following description is of a specific embodiment or a particular use of the invention, it is intended to be illustrative only, and not limiting of the claimed invention. The following description is intended to cover all combinations of features, alternatives, modifications and equivalents that are included in the spirit and scope of the invention, as defined in the appended claims.
In this description the terms “coiled tubing”, “coiled tubing string” shall be used interchangeably but in each instance shall mean the continuous steel tube pipe used in oil and gas drilling, production and maintenance operations.
The present invention is directed to a mobile coiled tubing unit, or rig as it is also known, having a moveable coiled tubing reel or a moveable mast, or both a moveable reel and mast. In one embodiment, the unit is configured for transport using a moveable coiled tubing reel and a moveable mast that is retractable into a mast sleeve to achieve dimensional requirements for transport. The apparatus itself can be moved laterally using retractable jacks and hydraulic cylinders for well alignment and moving from one well to the next. In one embodiment, the mast base moves forward and back to achieve well head alignment and injector alignment in various positions without need of repositioning or altering rig heights. The reel can also be raised to increase clearance to facilitate transportation over rough or uneven terrain, thereby allowing the rig to accommodate a larger reel.
The frame (12) comprises cross members (17) spanning the trailer in an orientation that is perpendicular to the longitudinal axis. In one embodiment, the frame members are reinforced or have greater structural strength in the vicinity of the reel.
The frame (12) has a plurality of ground-engaging wheels (14) proximate to its rear end (13) and a hitch (18) proximate to its front end (11). In one embodiment, the hitch (18) consists of a king pin that mates with fifth wheel mounted on the tractor (50). The hitch (18) and wheels (14) allow the apparatus (50) to be towed by a tractor (52) in a conventional manner. In one embodiment, a booster component attached to the back of the frame and/or a jeep disposed between the truck and the frame may be used to increase the capacity of the combined truck and trailer by distributing weight to the extra wheels. They can be used separately or together as needed in order to help the unit conform to highway weight regulations. During operation, the rig (50) may be decoupled from the tractor (52) and stabilized in a horizontal orientation using retractable hydraulic rig jacks (9) located proximate to each corner of the rectangular frame (12). Additional jack stands (9A) may be provided for use when the rig is not in use and not coupled to a tractor or jeep.
In one embodiment, a control cabin (16) is mounted on the frame in position proximate to the front end (11). The control cabin (16) contains all of the controls and instrumentation necessary to operate the apparatus (50). The control cabin may be provided on a separate trailer unit, or the unit may be remotely controlled.
A coiled tubing reel (46) is mounted on an axle (48) extending the width of the frame (12) and attached at each end to a reel drive frame assembly (66) mounted on the long sides of the frame (12). In one embodiment, the reel is approximately longitudinally centred on the frame. In the embodiment shown in the Figures, the reel axle is driven by hydraulic motors (70) through a pinion gear box (64) and a drive adapter plate (68), all of which is mounted on the reel drive frame assembly (66). The drive adapter plate has a keyed opening which mates with an axle adapter plate (69) fixed to the end of the axle (48). This configuration permits the reel axle (48) to slide into the drive adapter plates (68) during assembly. The adapter plates are fixed together with a drive clamp (67) which encircles the adapter plates (68, 69). The drive clamp may comprise of two semi-circular portions which are hinged together at one end, and which bolt together at the other.
In one embodiment, a closed-loop hydraulic motor (70) is used to control the torque being placed on the reel drive system, and tension of tubing between the reel and injector.
In one embodiment of the present invention, the reel assembly comprises a level wind assembly (71). The level wind assembly (71) positions the tubing (not shown) as it is being wound onto the reel (46). The level wind assembly (71) is comprised of a tubing guide (75), a level wind screw (72), and a hydraulic worm drive gear box (74), a controller and an encoder (73). The lateral position of the tubing guide (75) is controlled by the controller which determines the rotation of the level wind screw (72). In one embodiment, the level wind screw is driven through an enclosed hydraulic drive gear box (74), although other drive mechanisms such as a conventional chain and sprocket drive system may also be suitable. The worm drive gear box system reduces moving parts subject to wear and improves control of the tubing position on the reel. Tubing size adjustments can be made remotely with the controller so no mechanical changes need to be made. An encoder (73) accurately determines the lateral position of the tubing guide and the information is sent to the controller that controls the hydraulic worm drive (74).
The reel drive frame assembly (66) and the axle (48) and the reel (46) mounted thereon, are movable backwards and forwards along slide tracks (23) mounted on the frame (12). Accordingly, the reel (46) may be moved to a position more proximate to the front end (11), or more proximate to the rear end (13) as desired by the operator, or for transport purposes. The longitudinal actuation of the reel assembly (66) may accomplished with a pair of hydraulic cylinders (22).
The reel may also be raised vertically by pivoting the reel drive frame assembly (66) upwards about a pivoted connection (27) between the reel drive frame assembly (66) and the slide track (23), as shown in
The ability to move the reel (46) both longitudinally and vertically may provide several advantages. First, the reel (46) can be raised to increase clearance thereby facilitating transportation of the rig (50) over rough or uneven terrain. Second, the reel (46) when loaded with coiled tubing is extremely heavy, and the longitudinal and vertical movement of the reel (46) can be used to balance the load so that the apparatus (50) is more stable during transportation. For example, the reel (46) may be moved towards the second end (13) during transport and towards the first end (11) during operation. Furthermore, different jurisdictions have differing weight balance guidelines, rules and regulations for mobile coiled tubing rigs, and thus the ability to move the reel (46) may allow conformity with the rules of the relevant jurisdiction.
Mounted at the rear end (13) of the frame (12) is a mast assembly comprising a mast base (1). A mast sleeve (7) is pivotally mounted on the mast base (1). A mast (4) is slidably mounted within the mast sleeve (7) and has an upper end (38) and a lower end (40). A hydraulic cylinder (6) is used to extend or retract the mast (4) within the sleeve (7). In one embodiment, the sleeve is open at the bottom end, so that the bottom of the mast may protrude when in a lowered position. In one embodiment, the mast (4) may comprises two parallel masts each having its own mast base (1) and sleeve (7), interconnected by cross members (34) and a base cross member (1A). In one embodiment, one or more of the cross members (34) may be removably latched at one end and may be pivoted out of the way using a cylinder (35) to allow the cradle (60) to pass, as shown in
A pair of hydraulic cylinders (44) actuate the mast sleeve and mast between a transport position where the mast is substantially horizontal as shown in
A cradle (60) supports the injector (5) and goose neck (20) and is slidably moveable along the length of the mast (4). During transportation, the cradle (60), injector (5) and goose neck (20) are lowered to the lower end (40) of the mast (4). In one embodiment, the goose neck (20) is comprised of hinged parts to allow it to be transported in a folded configuration. To facilitate coiled tubing operations, when the mast is raised, in one embodiment, the cradle (60) is raised up the mast (4) by hydraulic motors driving pinion gears that engage a gear rack on each side of the mast (not shown). When the mast is raised to an operating position, and the cradle (60) is raised towards the upper end (38) of the mast (4), lubricators (28) and a blow out preventer (32) may be suspended beneath the injector (5) and are connected to the well head (30) in conventional manner.
The mast base (1), and correspondingly the mast sleeve (7) and the mast itself (4), are movable along the longitudinal axis (A) of the apparatus (50) by means of a sliding track (3) and a pair of hydraulic cylinders (2). In one embodiment, the mast base (1) can be extended such that it overhangs the rear end (13) of the frame (12) as shown in
In one embodiment, retractable hydraulic rig jack assemblies comprising rig jacks (9) are located at each corner of the rectangular frame (12), and each rig jack (9) is hingedly connected to a telescoping cylinder (10) that moves horizontally in and out of the frame (12).
When the apparatus is in a desired position, the telescoping cylinders (10) extend the jacks outwards. The jacks (9) are then deployed downwards to support the weight of the apparatus. As a result, the telescoping nature of the telescoping cylinders (10) allows lateral movement of the entire apparatus (50) when the weight of the apparatus (50) is supported by the jacks (9). The operator can utilize this lateral movement to align the injector (5) and lubricators (28) with the well head (30). During transportation, the retractable jacks (9) fold up and insert into the telescoping cylinders (10) and the telescoping cylinders (10) retract into the frame (12).
Accordingly, it can be understood that after the apparatus (50) has been positioned proximate to the well head (30) using the tractor, the cylinders (10) and jacks (9) are deployed to stabilize the apparatus (50) and the tractor (52) is decoupled. The reel (46) is moved into its operational position using the associated cylinders (22) and the mast is raised into its substantially vertical operational position using associated cylinders (44). The operator is then able to utilize the longitudinal movement of the mast (4) on the sliding tracks (3), and the lateral movement of the apparatus (50) using the cylinders (10) and jacks (9), the height of the mast (4) using the cylinders (6) to raise and lowers the mast within the sleeve (7), and the ability to raise and lower the injector (5) up and down the mast (4) in the cradle (60) to precisely align the injector (5) and the lubricators (28) with the well head (30). As lubricators (28) are added or removed depending on the nature of the coiled tubing operation, the operator may utilize the same movement capabilities to facilitate alignment of the injector (5) with the well head (30). The ability to alter the relative position of the various components of the apparatus, and the ability to move the apparatus (50) laterally, greatly reduces the time and effort required to achieve alignment in comparison to existing rigs.
During transportation, the mast (4) is fully retracted into the sleeve (7) thereby ensuring that the upper end (38) of the mast (4) does not protrude beyond the tractor (52). During operation, the mast (4) can be extended from the sleeve (7) to give the mast (4) additional height. Also, the operator can also retract or extend the mast (4) incrementally to assist with alignment of the injector (5) with the well head (30) and allows the operator to run the injector (5) in a relatively tall or short configuration.
In one embodiment, for smaller units the mast (4) may be transported separately and assembled and installed on the rig at site. As such, the rig would transport the reel and the injector between sites, as shown in
In another embodiment of the present invention, the control cabin may be a remote location on a separate trailer unit. In a further embodiment, the separate trailer unit may also comprise of any or all of a hydraulic accumulator for the blow out preventers, a HPU (Hydraulic Power Unit), a control cabin, a fuel tank, a generator and a tool room and a tool room.
Further, in the embodiments described above, hydraulic cylinders are utilized to move various components of the rig such as the reel (46), the mast base (1), mast (4), telescoping cylinders (10) and support jacks (9). One skilled in the art will understand that there may be other suitable mechanical means to achieve such movement such as rack and pinion drives with electric or hydraulic motors, or chain drives or cable drives, without deviating from the scope and spirit of the present invention.
As will be apparent to those skilled in the art, various modifications, adaptations and variations of the foregoing specific disclosure can be made without departing from the scope of the invention claimed herein.
This application claims the priority benefit of U.S. Provisional Patent Applications 61/657,548 filed Jun. 8, 2012 and 61/701,448 filed Sep. 14, 2012, the entire contents of both which are incorporated herein in their entirety (where permitted).
| Number | Date | Country | |
|---|---|---|---|
| 61657548 | Jun 2012 | US | |
| 61701448 | Sep 2012 | US |
