Dual-Reel Assembly For Coiled Tubing

Abstract

A coiled tubing reel assembly has two rotatable coiled, tubing reels that jointly hold a single continuous length of coiled tubing coiled wound around both of the reels. A drive mechanism provides controlled rotation to the reels and a levelwind mechanism positions the coiled tubing on the reels during reel rotation. The coiled tubing reel assembly allows transportation of greater continuous lengths of coiled tubing while minimizing the bending stresses associated with coiling and uncoiling the coiled tubing from the reels. Use of two coiled tubing reels also allows the overall dimensions of the reels to be minimized to facilitate transportation.

Description

FIELD OF THE INVENTION

The present invention pertains to coiled tubing units used in oil and gas industries. More specifically, the apparatus pertains to a coiled tubing unit having a dual reel coiled tubing reel assembly to transport coded tubing strings of greater continuous lengths from one location to another.

BACKGROUND

Coiled tubing units are used in workover operations on oil and gas wells to clean out the wellbores and to stimulate the production of oil and gas from the wells. Coiled tubing units are also used for both directional and non-directional drilling of oil and gas wells. A typical coiled tubing unit is comprised of as continuous length of tubing coiled around a tubing reel, an injector head, a control cabin, and a power pack. Depending upon the requirements of a particular well, the coiled tubing may have a continuous length of 20,000 feet or more and have a diameter ranging from 0.75 inches to as much as 4.0 inches. The length of coiled tubing transported on a tubing reel depends upon the dimensions of the reel and the size of the tubing.

The physical characteristics of the coiled tubing may also limit the length of continuous coiled tubing on a reel. Certain sizes of coiled tubing will require restrictions on the radius of curvature when be placed on a reel in order to keep bending stresses on the coiled tubing within acceptable limits. Doing so will require reels to have larger hubs upon which to wind the coiled tubing. These larger hubs will necessarily lead to larger reels in order to maximize the length of continuous tubing on the reel.

Trucks and trailers can transport a coiled tubing unit to a desired location as a complete package. More often, a truck or trailer transports some or all of the components of a coiled tubing unit separately. Truck and trailer height and width requirements imposed by roadway infrastructure and by transportation rules and regulations will limit the diameter and width of a coiled tubing reel and correspondingly the length of continuous coiled tubing on a reel. The available clearance at underpasses of bridges and by elevated obstructions such as streetlights and electrical wiring also impose height restrictions on trucks and trailers carrying coiled tubing reels.

State and local transportation regulations often require trucks and trailers carrying loads exceeding certain height and width standards to obtain special permitting. These regulations typically require a pilot car, or escort vehicle, with markings and warnings, to escort the load-carrying vehicle.

As a result of roadway infrastructure and by transportation rules and regulations, the route used by trucks or trailers transporting large equipment, such as a complete coiled tubing unit or a coiled tubing reel, must be planned well in advance to assure that the equipment can be transported efficiently and safely to a job site. Such pre-planning is not always feasible if it is necessary to bring a coiled tubing unit to a well site in an expedited fashion. Further, the expenses and delays associated with escort vehicles and permitting adds to the overall cost of well operations.

SUMMARY OF THE INVENTION

The present invention provides a coiled tubing reel assembly having two coiled tubing reels placed in tandem that jointly hold a single continuous coiled tubing string. The two reels are mounted in tandem on a longitudinally extending bed of a truck, a trailer, or a skid. When two or more reels are used, each reel rotates along a separate centrally positioned bearing and arbor arrangement. A drive mechanism rotates at least one of the reels to wind and unwind coiled tubing from the dual reels. The drive mechanism also provides a desired winding or unwinding torque to the reels and tension on the coiled tubing during the winding and unwinding of the coiled tubing. A levelwind mechanism distributes the coiled tubing in a desired position upon the tandem reels.

The coiled tubing string is wound onto the dual reels in a two-step process. First, the entire length of the tubing string is wound onto the hub of one reel by rotation of a drive mechanism in a conventional manner. Next, the distal end of the tubing string is attached to the hub of the second reel, and a portion of the tubing string is pulled from the first reel and wound onto the hub of the second reel. The result will leave coiled tubing on both the first and second reels with a segment of the tubing string spanning the reels at a tangent to the tubing coils on each reel. To unwind the coiled tubing from the dual reels, the winding process is reversed. Coordinating the tangential pulling force and the winding/unwinding torque will allow transfer from one reel to the other without backlashing. A levelwind mechanism controls the position of the tubing laterally along the reel keeping it neatly wrapped,

U.S. Pat. No. 6,494,397 to Jens Myklebust, U.S. Pat. No. 5,839,514 to Thomas C. Gipson, and. U.S. Pat. No. 3,646,599 to Alexander Lightbody, among others, describe drive mechanisms for coiled tubing reels. U.S. Pat. No. 5,090,039 to Michael F. Gard et al., U.S. Pat. No. 5,865,392 to Curtis G. Blount et al., and U.S. Pat. No. 6,264,128 to Rod W. Shampine et al, among others, describe levelwind mechanisms for coiled tubing reels. Similar drive and levelwind mechanism are employed in the tandem reel assembly of the present invention.

In one embodiment, the dual or tandem coiled tubing reel assembly of the present invention has reels with takedown side flanges. These takedown side flanges will allow an even further reduction of the in the height of the reels during transportation from one location to another while still allowing an increase in the length of a coiled tubing string that may be delivered to desired location.

The coiled tubing reel assembly of the present invention will reduce the cost, time, and logistical problems associated with height and width restrictions when transporting coiled tubing units to a desired location such as a well site. Using two or more reels for a single length of coiled tubing will allow the diameter of the hub of each of the reels to be increased. Increasing the hub diameter will increase the minimum radius of curvature of the reel to reduce bending stresses in the coiled tubing caused by winding on a reel without limiting the length of the continuous coiled tubing carried by a transporting vehicle. The coiled tubing reel assembly having at least two coiled tubing reels will allow as reduction in the height of the reels required to accommodate a coiled tubing string of a desired continuous length of coiled tubing and enhance the available clearance at roadway underpasses of bridges and other elevated obstructions.

The principle object of the invention is provide two or more reels for a string of coiled tubing in order to maximize the length of coiled tubing for a given reel width and height.

Another object of the present invention is to provide a coiled tubing reel assembly for transporting greater continuous lengths of coiled tubing without regard to roadway height and width restrictions.

An additional object is to provide a coiled tubing reel assembly for transporting greater lengths of continuous coiled tubing while maintaining a larger interior reel hub diameter to reduce the bending stress and resulting metal fatigue on the coiled tubing string resulting from being wound around the coiled tubing reel.

Still another object of this invention is to provide a coiled tubing reel assembly for transporting a continuous length of coiled tubing on two reels in order to reduce the cost of transportation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view of the coiled tubing reel assembly mounted on the bed of a trailer or a truck and trailer combination.

FIG. 2 is a schematic side view of the coiled tubing reel assembly mounted on a skid.

FIG. 3a is a schematic side view illustrating the first step of the process of winding or coiling a single continuous length of coiled tubing onto the dual reels, i.e., winding the entire length of coiled tubing onto a first reel of the dual reels.

FIG. 3b is a schematic side view illustrating the second step of the winding process, i.e., winding a portion of the length of coiled tubing onto the second reel of the dual reels.

FIG. 4a is a schematic side view illustrating the first step process of the process of unwinding or uncoiling a single continuous length of coiled tubing onto the dual reels, i.e., unwinding the entire length of coiled tubing from the second reel of the dual reels onto the first reel of the dual reels.

FIG. 4b is a schematic side view illustrating the completed first step of the unwinding process with the coiled tubing completely unwound from the second reel of the dual reels.

FIG. 5 is a schematic end cross-section view of a coiled tubing reel that may be incorporated in the coiled tubing reel assembly of FIG. 1.

FIG. 6 is a schematic end cross-section view of another embodiment of the coiled tubing reel that may be incorporated in the coiled tubing reel assembly of FIG. 1.

FIG. 7 is a schematic end view of an embodiment of the reels of the coiled tubing reel of FIG. 1 with collapsible flange segments.

FIG. 8 is a partial schematic cross-section view of a reel flange of the coiled tubing reel of FIG. 7 at the junction of the flange segments showing a flange latch with the collapsible flange segment in an erect position.

FIG. 9 is a schematic side view of the coiled tubing reel assembly mounted on the bed of a trailer or a truck and trailer combination with the reels of FIG. 7 in a collapsed position for clearing an overhead obstruction.

DETAILED DESCRIPTION OF THE DRAWINGS

Unless otherwise specified, the drawings provide schematic diagrams of exemplary features of varying detail of certain embodiments of the invention. Unless otherwise specified, features, components, elements, and/or aspects of the drawings can be otherwise combined, interconnected, sequenced, separated, interchanged, positioned, and/or rearranged without materially departing from the disclosed invention. Elements illustrated in the drawings are not to scale or shown with precise accuracy and are primarily intended to facilitate an understanding of the disclosed invention. Features well established in the art and that do not bear upon points of novelty are omitted in the interest of descriptive clarity.

FIG. 1 is a schematic side view of the coiled tubing reel assembly (10) mounted on the bed (42) of a trailer or a truck and trailer combination (40). The reel assembly (10) shown is a dual reel assembly comprised of first and second coiled tubing reels (12) rotatably mounted on the axles (14) of reel supports (45). The reel supports (45) are arranged in tandem along the length of the trailer bed (42) with that the axles (14) of each reel support (45) positioned parallel to each other. The reels (12) jointly hold a continuous string of coiled tubing (30).

The reel supports (45) are fitted with a drive mechanism (46) having a motor and belt, chain, gear, or other drive system for rotating and controlling the rotation of the reels (12). Levelwind mechanisms (47) are provided to aid in placing and positioning the coiled tubing (30) on each reel (12). Reel drive mechanisms and levelwind mechanisms are known in the art and any one of a number of such mechanisms may be incorporated into the reel assembly (10).

FIG. 2 shows the coiled tubing reel assembly (10) of FIG. 1 mounted on a skid (43). Mounting the coiled tubing reel assembly (10) on the skid (43) will facilitate transportation on marine vessels such as a barge or a supply boat when the assembly (10) is shipped for use on at offshore location. The skid (43) may be provided with pad eyes (41) for attachment to slings to facilitate lifting and placing the skid (43) on a vessel or on the bed of truck or trailer for transportation.

The process of winding or coiling the single continuous coiled tubing (30) onto the dual reels (12) of the assembly (10) is illustrated in FIGS. 3a and 3b. The process of unwinding or uncoiling the single length of coiled number is shown in FIGS. 4a and 4b. Each reel (12) rotates on its axle (14) of support (45) during winding and unwinding process. The direction of rotation is shown as R in FIGS. 3a, 3b, 4a, and 4b. The direction of torque applied counter to the direction of rotation R is shown as T in FIGS. 3a, 3b, 4a, and 4b.

The first step of winding process, as shown in FIG. 3a, is winding the entire tubing string (30) around the hub of a first rotatable reel (12). For winding to commence, an end of the tubing string (30) is first affixed to the hub of the first reel. Then the reel drive mechanism (46) is the used to rotate the reel to apply torque to pull the tubing string (30) from a source spool and wind it onto the first reel (12). This continues until desired entire length tubing string (30) is wound upon the first reel (12). The second reel (12) is not used in this initial step.

The second step of winding process, as shown in FIG. 3b, is winding a portion of the tubing string (30) around the hub of a first rotatable reel (12). The distal end of the tubing string (30) on the first reel (12) of step 1 is affixed to the hub of the second reel (12). The drive mechanism (46) of the second reel (12) is then rotated to apply torque to the second reel (12) to pull a portion of the tubing coiled string (30) from the first reel (12) unto the second reel (12). Rotation of the second reel (12) is continues until a desired portion of the coiled tubing string (30) on the first reel (12) is wound onto the second reel (12). The drive mechanism (46) of the first reel (12) is engaged to provide rotational torque counter to the rotation of the reels (12) to keep the tubing string (30) under tension. This tension, along with the levelwind mechanisms (47), prevents backlash and keeps the coiled tubing string (30) neatly wrapped on the reels (12). The drive and levelwind mechanisms are not shown for clarity purposes.

The first step of the unwinding or uncoiling the single continuous coiled tubing string (30) from the first and second dual reels (12) of the assembly (10) is shown in FIG. 4a. For unwinding the drive mechanism (47) of the first reel (12) is used to apply rotation in direction R to pull the portion of tubing string (30) on second reel (12) onto the first reel (12) until the entire tubing string (12) is wound around the first tubing reel (12) as shown in FIG. 4b. The tubing string (30) may then be pulled from this first reel (12) by other means for injection into a well bore or pipeline or for being wound upon an additional reel for storage or disposal. The drive mechanism (46) maintains rotational torque in direction T counter to the unwinding rotation R during this unwinding process to prevent backlash.

Various rollers, tubing guides, and bend limiting devices can also be used to restrict or limit the bending of the coiled tubing to an acceptable level when coiling and an uncoiling coiled tubing string (30) onto and from the dual the reels (12). Bend limiting and tubing feeding devices have been described in U.S. Pat. No. 2,576,009 to Calhoun, et al U.S. Pat. No. 5,660,235 to Sola; U.S. Pat. No 5,360,075 to Gray and elsewhere and are known in the art. Similar bend limiting mechanisms may be employed in the reel assembly (10) of the present invention.

FIGS. 5 and 6 show embodiments of coiled tubing reels (12) that may be incorporated into the reel assembly (12). The reels (12) in FIGS. 5 and 6 have a hub (20) with a bore (18) for mounting the reel on axle (14) of reel supports (45) and reel flanges (22) that extend radially outward from the hubs (20). The height (H) and width (W) of the reels in FIGS. 7 and 6 are the same. The reels of FIG. 5 and FIG. 6 differ only in the diameter of their respective hubs (20), the diameter of hub (20) in FIG. 5 having a diameter (A) and the diameter of hub (20) in FIG. 6 having a greater diameter designated as (AA). This difference in diameters creates a flange (22) having a radial dimension (B) in FIG. 5 and a flange (22) having a lesser radial dimension (BB) in FIG. 6.

It will be appreciated that coiled tubing coiled around hub (20) of the reel (12) in FIG. 5 will result in producing greater bending stresses than when that same coiled tubing is coiled around the hub (20) in FIG. 6 because the hub (20) in FIG. 6 has a greater diameter than the hub (20) in FIG. 5. It will also be appreciated that a greater length of coiled tubing may be coiled around the reel (12) in FIG. 5 than the reel (12) of FIG. 6 because the flanges (22) extend radially outward from the hub (20) a greater distances than the flange (22) of the reel (12) FIG. 6. When the coiled tubing reel assembly (10) incorporates the reel (12) of FIG. 6, the coiled tubing capacity is greater than the capacity of a single reel (12) as shown in FIG. 5 and the bending stresses placed upon the coiled tubing will be minimized because of the greater hub diameter (AA) of the reel (12) in FIG. 6.

FIG. 7 shows an alternate embodiment for flanges (22) the reels (12) of the coiled tubing reel assembly (10). In FIG. 7 the radially extending flanges (22) are comprised of a fixed flange segment (24) and a collapsible or articulating takedown flange segment (26). The takedown flange segment (26) is pivotally attached to the fixed flange segment (24) by a hinge or hinges (28). Flange latches (28) between flange segments (24) and (26) hold flange segments (26) in an erect position as shown in FIG. 8.

FIG. 8 is a partial schematic cross-section view of a reel flange (22) of the coiled tubing reel of FIG. 7 at the junction of the flange segments (24) and (26). The section shows is flange latch (16) with the collapsible or takedown flange segment (26) in an erect position atop fixed flange section (24). Flange latch (16) is comprised of a tubular link (25) mounted of fixed flange segment (24) and a corresponding tubular link (25) mounted on takedown flange segment (26). A pin or a threaded bolt (27) in the corresponding tubular links (25) and secured with a removable nut (29) holds flange segment (26) in an erect position. To takedown or collapse flange segment (26), nut (29) is removed and pin or bolt (27) is removed from links (25). This will allow flange segment (26) to pivot or articulate on hinge (28) to the collapsed position shown in FIG. 7. Similar latches (16) may be furnished to releasably hold a flange segment (26) in place in the collapsed position shown in FIG. 7.

FIG. 9 is a schematic side view of the coiled tubing reel assembly (10) mounted on the bed (42) of a trailer or a truck and trailer combination (40) with the takedown flanges (26) shown in FIG. 7. As shown the takedown flanges (26) are in a collapsed position. Collapsing the flanges (26) of the reels (12) will further enhance the clearance between the vehicle (40) and assembly (10) and an overhead obstruction (60).

The coiled tubing reel assembly (10) and method of Applicant's invention and many of its attendant advantages will be understood and appreciated from the foregoing description by those skilled in the art. The description and drawings provide only exemplary embodiments of the coiled tubing reel assembly (10) and its methods of use. The invention can be practiced by other than the described embodiments, which are presented only for illustration and not limitation. Changes in the form, construction, and arrangement of the parts of the assembly (10) may be made without departing from the spirit and scope of the invention or sacrificing any of the invention's material advantages.

Claims

1. A coiled tubing reel assembly comprising:

(a) a first reel;

(b) a second reel;

(c) at least one drive mechanism providing controlled rotation of said first and second reels; and

(d) a single continuous length of coiled tubing coiled around both said first reel and said second reel.

2. The coiled tubing reel assembly recited in claim 1 further comprising a levelwind mechanism positioning said length of coiled tubing on said first reel.

3. The coiled tubing reel assembly recited in claim 2 further comprising a levelwind mechanism positioning said length of coiled tubing on said second reel.

4. The coiled tubing reel assembly recited in claim 3 wherein said first and second reels are mounted on the bed of a transport vehicle.

5. The coiled tubing reel assembly recited in claim 2 wherein said first and second reels are mounted on a skid.

6. The coiled tubing reel assembly recited in claim 3 wherein said first and second reels are mounted on a skid.

7. The coiled tubing reel assembly recited in claim 3 wherein said first and second reels have a radially extending fixed flange segment and a detachable flange segment.

8. The coiled tubing reel assembly recited in claim 7 further comprising a hinge holding said detachable flange segment to said fixed flange segment.

9. The coiled tubing reel assembly recited in claim 8 further comprising a latch holding said detachable flange segment in an erect position relative to said fixed flange segment.

10. A coiled tubing reel assembly comprising:.

(a) two rotatable reels;

(b) a drive mechanism providing controlled rotation for said reels;

(c) a levelwind mechanism engaging a continuous length of coiled tubing; and

(c) wherein said rotatable reels jointly hold a continuous length of coiled tubing wound around said rotatable reels.

11. The coiled tubing reel assembly recited in claim 10 wherein said rotatable reels are mounted on the bed of a transport vehicle.

12. The coiled tubing reel assembly recited in claim 10 wherein said rotatable reels are mounted on a skid.

13. The coiled tubing reel assembly recited in claim 10 wherein said rotatable reels have a radially extending fixed flange and a radially extending detachable flange segment.

14. A method for transporting a continuous segment of coiled tubing comprising the steps of:

(a) providing two rotatable reels;

(b) providing a drive mechanism providing controlled rotation for said reels;

(c) providing a continuous length of coiled tubing;

(d) rotating said reels with said drive mechanism whereby said continuous length of coiled tubing is coiled around each of said rotatable reels; and

(e) wherein said rotatable reels jointly hold said continuous length of coiled tubing.

15. The method for transporting a continuous segment of coiled tubing recited in claim 14 comprising the additional steps of:

(a) providing a levelwind mechanism;

(b) engaging said continuous length of coiled tubing with said levelwind mechanism; and

(c) positioning said length of coiled tubing on said reels.

16. The method for transporting a continuous segment of coiled tubing recited in claim 15 comprising the additional step of mounting said rotatable reels on a skid.

17. The method for transporting a continuous segment of coiled tubing recited in claim 15 comprising the additional step of mounting said rotatable reels on the bed of a vehicle.

18. The method for transporting a continuous segment of coiled tubing recited in claim 17 comprising the additional steps of:

(a) providing each of said rotatable reels with a fixed flange segment and detachable flange segment;

(b) detaching said detachable flange segment from said fixed segment of said rotatable reels; and

(c) transporting said rotatable reels on said vehicle.

19. The method for transporting a continuous segment of coiled tubing recited in claim 18 comprising the additional steps of:

(a) attaching said detachable flange segment to said fixed segment of said rotatable reels; and

(b) uncoiling said coiled tubing from each of said rotatable reels.