LEVEL-WIND SYSTEM FOR COILED TUBING

FIELD OF THE INVENTION

[0001] The present invention relates in general to coil tubing systems and in particular to a level- wind system for coil tubing units.

BACKGROUND

[0002] Level-wind systems have been provided for spooling coiled tubing onto a reel when removing the tubing from a well and guiding the tubing off of the reel when injecting the tubing in a well. In many of the prior systems, the level-wind system is positioned by the reel's drive mechanism. These systems included many shortcomings that result in mechanical failures or failure to properly spool the tubing on or off of the reel. Additionally, the tubing guide heads of these prior systems are not adaptable to various tubing diameters and are subject to excess failures. These prior systems are also expensive to implement, maintain, and operate.

[0003] An improved level-wind system was taught in co-owned U.S. Patent 6,264,128, which is incorporated by reference herein. The level-wind system of the '128 patent addressed many of the shortcomings of the prior level- wind systems.

[0004] However, there still exists a need to further address the shortcomings of the prior level- wind systems. It is a still further desire to provide an improved tubing guide head.

SUMMARY OF THE INVENTION

[0005] Thus, it is a desire of the present invention to provide a level-wind system that addresses shortcomings and disadvantages of the prior level-wind systems.

[0006] It is a further desire of the present invention to provide a level-wind system that is less expensive to manufacture, maintain, and operate relative to prior art systems.

[0007] It is a still further desire of the present invention to provide a level-wind system that reduces points of failures in relation to the prior systems.

[0008] It is a still further desire of the present invention to provide a level-wind system which can accommodate multiple sizes of tubing without requiring adjustment or replacement of parts.

[0009] Accordingly, a level- wind head and level-wind system for coiled tubing is provided. The system including a coiled tubing reel mounted for rotation about a horizontal axis, a level-wind head comprising only one pair rollers mounted in spaced relation to one another to form a throat sized to pass various outside diameter coiled tubing, without replacement or repositioning of the pair of rollers, to or from the reel, and a positioning system in connection with the level-wind head for selectively positioning the level-wind head proximate the reel.

[0010] The foregoing has outlined the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The foregoing and other features and aspects of the present invention will be best understood with reference to the following detailed description of a specific embodiment of the invention, when read in conjunction with the accompanying drawings, wherein:

[0012] Figure 1 is a side-view of an embodiment of a level-wind system of the present invention mounted on a trailer;

[0013] Figure 2 is a perspective view of an embodiment of a skid-mounted coiled tubing system of the present invention;

[0014] Figure 3 is a perspective view of a level-wind system, as illustrated in Figure 2, in isolation;

[0015] Figure 4 is a perspective view of another embodiment of a skid-mounted coiled tubing system of the present invention in isolation;

[0016] Figure 5 is a front view of the coiled tubing system of Figure 5; and

[0017] Figure 6 is a view of a level-wind head of the present invention illustrating the passing of coiled tubing.

DETAILED DESCRIPTION

[0018] Refer now to the drawings wherein depicted elements are not necessarily shown to scale and wherein like or similar elements are designated by the same reference numeral through the several views.

[0019] Figure 1 is a side view of an embodiment of a trailer mounted coiled tubing unit of the present invention, generally designated by the numeral 10. A reel 12 for spooling coiled tubing T is mounted on a trailer. Coiled tubing T is spooled from reel 12 to injector 14 for injecting coiled tubing T into a well, and spooled onto reel 12 when removing coiled tubing T from the well. Reel 12 having an axle 16 is rotatably mounted on struts 18. Axle 16 defines the longitudinal axis of reel 12. A hydraulic motor 20 is connected to reel 12 for rotating reel 12. Hydraulic motor 20 and the drive connections, not shown, to reel 12 are generally referred to as the reel's drive mechanism.

[0020] A level-wind system 22 having an arm 24 and a level-wind head, or roller head, 26 is positioned proximate reel 12. Level-wind head 26 serves to hold and guide coiled tubing T to and from reel 12. Arm 24 of the present embodiment includes an elongated member 28 having a first end 30 pivotedly connected to a support structure 32 and a free end 34. Level-wind head 26 is connected to free end 34.

[0021] A positioning system comprising a vertical positioning mechanism 36 and a horizontal positioning mechanism 38 in connection with arm 24 may be provided. The positioning system facilitates precise positioning of level- wind head 26 relative to reel 12. A positioning system is provided in co-owned US Patent 6,264,138 which is incorporated herein by reference. The

positioning system may be operated independently of the rotation of reel 12. Desirably, the positioning system maintains a force on coiled tubing T.

[0022] Figure 2 is a perspective view of an embodiment of a skid-mounted coiled tubing system 10 of the present invention in isolation. Reel 12 and axle 16 are rotatably mounted on struts 18 of support structure 32.

[0023] In the embodiment of Figure 2, arm 24 is an elongated member 28 having a first end 30 and a free end 34. First end 30 is pivotedly connected to support structure 32 permitting both vertical and horizontal movement of arm 24 in relation to the longitudinal axis (axle 16) of reel 12. Level- wind head 26 is rigidly connected to free end 34 of arm 24 preventing rotating, pivoting, and translating movement of level-wind head 26 in relation to arm 24.

[0024] Vertical and horizontal positioning mechanisms 36, 38 are shown connected between arm 24 and support structure 32 for positioning level-wind head 26 relative to reel 26. As illustrated positioning mechanisms 36, 38 are hydraulic cylinders. Again, the positioning system and hydraulic circuits are described in US Patent 6,264,128 which is incorporated herein. Other positioning systems may be utilized and fall within the scope of the present invention.

[0025] Figure 3 is a perspective view of a level-wind system 22, as illustrated in Figure 2, in isolation. Level-wind head 26 includes a frame 40 holding a single pair of rotating rollers 42a and 42b. Rollers 42a and 42b are each substantially one-sheet hyperboloid shaped. Rollers 42a and 42b are spaced apart for each other in a manner to form a throat 44 of sufficient size to pass

coiled tubing of varying outside diameters, without repositioning or replacing rollers 42. The operation and positioning of rollers 42 is described further in relation to Figure 6.

[0026] Figure 4 is a perspective view of another embodiment of a skid-mounted coiled tubing system 10 of the present invention in isolation. Reel 12 and axle 16 are rotatably mounted on struts 18 of structure 32. Level-wind head 26 is connected to arm 24. Level-wind system 22 is connected within an arm assembly 46 to facilitate the positioning of level-wind head 26 relative to reel 12.

[0027] Arm assembly 46 is described with reference to Figures 4 and 5. Arm assembly 46 includes a pair of extensions 48a and 48b, a cross-bar 50, and horizontal positioning mechanism 38 comprising a leadscrew 52 and an actuator 54. Extensions 48a, 48b are elongated members each having a first end 56 and a distal end 58. First ends 56 are hingedly connected to support structure 32. A cross-bar 50 may be connected between the distal ends 58a, 58b to provide structural support. Leadscrew 52 includes threads and is rotatably mounted between distal ends 58a, 58b. An actuator 54 is functionally connected to leadscrew 52 to provide controlled rotational movement. Actuator 54 may be an electric motor or hydraulic driving mechanisms. Actuator 54 may be operationally connected to the drive mechanism of reel 12 or may be controlled independent of reel's 12 drive mechanism.

[0028] Horizontal positioning mechanism 38 is a leadscrew system for converting rotary to linear motion. Horizontal position mechanism 38 includes leadscrew 52, actuator 54 and arm 24. Arm 24 is a nut that is slidingly mounted on leadscrew 52 in a manner such that arm 24 and level-wind head 26 move substantially parallel to the longitudinal axis of reel 12 in response to

the rotation of leadscrew 52 as illustrated by the arrow in Figure 5. The leadscrew system may include, but is not limited to, acme screws and ballscrews.

[0029] Referring back to Figure 4, vertical position mechanism 36 is shown connected between support structure 32 and arm assembly 46. Vertical position mechanism 36 operates as described above an in U.S. Patent 6,264,128.

[0030] Figure 6 is a view of a level-wind head 26 of the present invention showing coiled tubing passing through the head at various angles. Rollers 42a and 42b are one-sheet hyperboloid shaped members spaced apart in a manner to form a throat 44 of sufficient size to pass coil tubing T of various diameters, without requiring the repositioning or replacement of rollers 42a and 42b. Desirably, throat 44 is sized to pass coiled tubing T having an outside diameter substantially from 1 inch to 2.5 inches. In particular, the throat is desired to accommodate coiled tubing T having an outside diameter of 1.25 inches to 2.375 inches. Rollers 42 may be constructed of various material, including, but not limited to, Nylatron, stainless steel, or polyurethane. The utilization of a material having self-lubricating properties, such as Nylatron, eliminates the requirement of bearing thus reducing a point of failure and an element of additional cost.

[0031] As described with reference to Figures 1-6, level-wind head 26 may be rigidly or non- moveably connected to arm 24. By eliminating the pivoting requirement and connection of the prior level-wind heads another point of failure and cost is eliminated. The pivoting requirement of level-wind head 26 in relation to arm 24 is eliminated by facilitating the passing of coiled tubing T through level-wind head 26 at various angles.

[0032] As shown in Figure 6, the single pair of rollers 42 having a one-sheet hyperboloid shape facilitate the passing of multiple diameter coiled tubing T at various angles through throat 44. Various strings of coiled tubing are shown superimposed upon one-another to illustrate various angles of travel through throat 44. The various coiled tubing strings are identified as Tl, T2, T3, T4, T5, T6, T7. and T8.

[0033] From the foregoing detailed description of specific embodiments of the invention, it should be apparent that a level-wind coil tubing system that is novel and unobvious has been disclosed. Although specific embodiments of the invention have been disclosed herein in some detail, this has been done solely for the purposes of describing various features and aspects of the invention, and is not intended to be limiting with respect to the scope of the invention. It is contemplated that various substitutions, alterations, and/or modifications, including but not limited to those implementation variations which may have been suggested herein, may be made to the disclosed embodiments without departing from the spirit and scope of the invention as defined by the appended claims which follow.