IMPROVEMENTS RELATING TO COILED TUBING

Abstract

A length of tubing and related apparatus and methods are described, where the length of tubing is deployable from a coiled configuration to an uncoiled configuration for performing a coiled tubing operation in a wellbore. The length of tubing includes a pipe of metal, and a liner of composite material that lines the pipe. The liner or the lined pipe includes a wall structure that incorporates means to communicate at least one service along the tubing.

Claims

1. A length of tubing that is deployable from a coiled configuration to an uncoiled configuration for performing a coiled tubing operation in a wellbore, the length of tubing comprising: a pipe of metal; and a liner of composite material that lines the pipe, the liner or the lined pipe comprising a wall structure that incorporates means to communicate at least one service along the tubing.

2. The length of tubing as claimed in claim 1, wherein the communicated service comprises at least one of electric power, data, and control fluid.

3. The length of tubing as claimed in claim 1, wherein the means incorporated to communicate the service along the tubing comprises at least one of an electrical conductor, an optical fiber, and a fluid channel.

4. The length of tubing as claimed in claim 1, wherein the metal comprises steel.

5. The length of tubing as claimed in claim 1, wherein the composite material comprises fibers combined with a polymer.

6. The length of tubing as claimed in claim 5, wherein the polymer comprises at least one thermoplastic polymer selected from the group comprising: polyketones, polyphenylenesulphides, and fluorinated thermoplastics.

7. The length of tubing as claimed in claim 5, wherein the composite material comprises fibers selected from the group consisting of glass fibers, aramid fibers, carbon fibers, steel fibers, any combination of said fibres; thereof, and UD tapes of said fibres thereof.

8. The length of tubing as claimed in claim 1, wherein the liner of composite material comprises fibers combined with a polymer by at least one of pull-winding, pultrusion, and filament winding.

9. The length of tubing as claimed in claim 1, wherein the means incorporated to communicate the service along the tubing comprises at least one of an elongate member taking a spiral trajectory or a parallel trajectory along the tubing.

10. A length of tubing as claimed in claim 1, wherein the means incorporated to communicate the service along the tubing comprises an optical sensing fiber for sensing a condition in the tubing or for communicating data or signals along the tubing.

11. The length of tubing as claimed in claim 1, wherein the length of tubing is configured to provide a flowline for conveying a production fluid from a subsea production well toward a surface along an inside of the length of tubing, and wherein the means incorporated to communicate the service along the tubing is configured to generate heat inside the length of tubing to facilitate the conveyance of the production fluid.

12. The length of tubing as claimed in claim 1, wherein the liner is fitted to the pipe to have an outer surface of the liner in friction contact with an inside of the pipe.

13. The length of tubing as claimed in claim 1, wherein the pipe of metal is an outer pipe and the liner is an inner pipe within the outer pipe, and wherein the means to communicate the service along the tubing is incorporated in the material of the wall structure of the inner pipe.

14. The length of tubing is a coiled tubing, wherein the coiled tubing is fitted onto a reel.

15. (canceled)

16. A method of producing a length of coiled tubing that is deployable from a coiled configuration to an uncoiled configuration for performing a coiled tubing operation in a wellbore and comprising a pipe of metal and a liner of composite material that lines the pipe, the method comprising the steps of: providing the pipe of metal; and lining an inside of the pipe with a liner of composite material, the wall structure of the liner or the lined pipe incorporating means to communicate the service along the tubing.

17. The method as claimed in claim 16 further comprising producing the liner, the liner being produced by combining fibers and a polymer in one or more steps of pultrusion, filament winding, or pull winding.

18. The method as claimed in claim 16 or 17, wherein the pipe of metal is lined by inserting the liner into the pipe.

19. The method as claimed in claim 18, wherein the liner is inserted by applying pressure inside the liner against a closed end surface to drive the liner into the pipe.

20. A method of performing a coiled tubing operation in a wellbore comprising: supporting a tool at an end of a length of tubing that is deployable from a coiled configuration to an uncoiled configuration for performing a coiled tubing operation in a wellbore and comprising a pipe of metal and a liner of composite material that lines the pipe; uncoiling the length of tubing from a drum into the well to deploy the tool in the wellbore; performing the operation using the tool; and communicating power, data or signals along the coiled tubing through the means incorporated in the material of a wall structure of the liner.

21. The method as claimed in claim 20, wherein the liner of composite material is adapted for lining an outer pipe of metal for producing the length of tubing and comprises the wall structure that incorporates means to communicate a service along the tubing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] There will now be described, by way of example only, embodiments of the invention, with reference to the accompanying drawings, in which:

[0041] FIG. 1 is a perspective sectional view of a length of tubing according to an embodiment of the invention;

[0042] FIG. 2 is a perspective view of a liner for a length of tubing according to an embodiment of the invention;

[0043] FIG. 3 is a sectional view of the length of tubing perpendicular to the longitudinal direction according to an embodiment of the invention;

[0044] FIG. 4 is a schematic representation of a step of a method of producing the tubing; and

[0045] FIG. 5 is a schematic representation of performing an operation in the wellbore using the tubing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0046] The length of tubing 1 in FIG. 1 has an outer pipe 3 of steel and an inner liner pipe 4 of composite material incorporating means in the form of elongate electrical conductors 7 for communicating power, data or signals along the tubing.

[0047] The tubing 1 has a central longitudinal axis 21. The electrical conductors 7 extend axially in parallel along the tubing 1. The electrical conductors are each associated with a radially protruding rib 8. The ribs 8 are in friction contact against an inside of the outer pipe 3. The liner pipe 4 is inserted into the outer pipe 3 in order to line the pipe to produce the lined tubing. The ribs 8 act to provide stand off from the inner surface of the pipe 3 so as to facilitate reduction of friction and provide space for escape of air upon inserting the liner into place.

[0048] In use, coiled tubing comprising the length of tubing of FIG. 1 can be employed in a wellbore with a tool on a far end of the tubing to perform an operation in the wellbore. The length of tubing is flexible and is deployed from coiled configuration on the reel to an uncoiled configuration where it is used in the wellbore. A work fluid for performing the operation can be transmitted through the bore 9 of the tubing 1 into the wellbore. Example work fluids include proppants or chemicals e.g., for treating the wellbore or formation.

[0049] In FIG. 2, an alternative liner pipe 4 is illustrated. The liner pipe of FIG. 2 can be fitted similarly to an outer pipe 3. In this case however, the liner pipe 4 has communication members in the form of three optical fibers 17 for data transmission along the tubing and three electrical conductors 7 for transmitting electrical power along the tubing. The ribs 8 are wider and fewer than in FIG. 1.

[0050] In FIG. 3, an alternative tubing 1 is depicted. The liner pipe 4 in this example does not have ribs, but the liner pipe is dimensioned relative to the outer pipe 3 to provide clearance 14 between the outer surface of the liner pipe 4 and the inner surface of the outer pipe 3, sufficient to allow insertion without succumbing to friction effects. Three conductors 7 are provided and incorporated into the material of the liner pipe.

[0051] The liner pipe 4 can be inserted into the outer pipe 3 as indicated in FIG. 4. An end of the liner pipe 4 is closed off by closure member 33. The liner pipe, closed end first, is inserted into the outer pipe 3. The interior 36 of the inner pipe is pressurized by delivering a pressurized fluid through inlet 37 at the opposite end. The pressure in the interior 36 acts against a surface of the closure member and drives the liner pipe 4 into the outer pipe to thereby form the lined tubing 1.

[0052] In use, apparatus 100 is generally depicted where coiled tubing 1 is uncoiled from a reel 105 that is located topsides at surface 106, e.g., a rig. The tubing 1 is being used in a wellbore 109 for performing a downhole operation in the wellbore. Sensors (not shown) are provided on the coiled tubing 1 in the wellbore. Data from the sensors are communicated up through the coiled tubing 1 to surface through the communication means, e.g., conductor or optical fiber, in the material of the wall structure of the liner pipe of the tubing. Thus, data can be obtained during wellbore operations. Work fluid can be transmitted through the interior of the tubing 1 and delivered into the wellbore in the wellbore operation as indicated by arrow W.

[0053] Operational temperatures in the well are typically up to 150 to 170 degrees Celsius. The coiled tubing is subjected to tough chemical conditions. Materials are selected and the coiled tubing constructed accordingly. The outer pipe is in this case is a flexible pipe of steel.

[0054] The composite material of the liner is a combination of polymer and fibers, and the polymer can be for instance a thermoplastic polymer such as one of polyetheretherketone PEEK, polyethylene sulphide PPS, and perfluoroalkoxy PFA. PVDF is an alternative for lower temperatures below 140 degrees Celsius. PEEK can be advantageous in the well in that it has low water absorption, and can cope well with chemicals such as ammonia gas, carbon monoxide gas, ethylene glycol (50%), hydrogen sulphide gas, methane, phosphoric acid (50%), sodium hydroxide solution, and sulphur dioxide gas. PPS can be advantageous in that it can have very high resistance to thermal degradation and chemical reactivity and low moisture absorption under high heat and humidity conditions. It can cope well with methane, carbon dioxide, hydrogen sulphide, hydrogen gas, nitrogen, potassium chloride, sulphur dioxide, salt water/seawater. PFA resins may be advantageous in good chemical and thermal stability.

[0055] The composite fibers can be selected suitably for reinforcement of the tube for facilitating circumferential, axial and radial strength to withstand high operating pressures and tensile and compression stresses. The fibers can be provided in fiber reinforced UD tapes with carbon or glass fibers. The form of fiber reinforcement can be decided as appropriate for the processing technique for producing the tubing.

[0056] The liner pipe of composite material can suitably be produced by pull winding. The conductors, e.g., wires, are incorporated in the wall of the liner pipe by appropriate placement of the conductor in the course of the manufacturing process. A monitored process is employed, where the wire/conductor is guided into the center of the wall at the appropriate stage, e.g., after an inner portion of the wall has been formed and before an outer portion of the wall is formed. Visible light and/or x-ray illumination of the liner pipe under manufacture is used to control the process and ensure proper placement of the conductor, preferably embedded centrally in the wall material of the composite liner pipe. The conductor can be positioned in desired position within a tolerance in the range of 0.3 mm to 0.5 mm. The ribs 8 of the external structure of the tubing are produced by the die and/or mold in the pull winding process. The die/mold gives the desired design, shape and structure which can be predefined as required.

[0057] The technique can provide significant benefits as data can be collected and retrieved in real time and throughout operations being carried out in the wellbore. The provision of the communication member in the material of the wall of the tubing can provide a robust positioning for the communication member, where it may not be susceptible to the effects of work fluid transmitted through the tubing. Thus, risks of damage, wear, and pauses in operations can be avoided or reduced. Provision of the liner, in effect in the form of a flexible sock that can be readily inserted and retrofitted to metal coiled tubing pipes. The outer pipe of steel can in itself be comparable in performance of flexure, strength, integrity etc. to traditional steel coiled tubing, although the performance is enhanced in the present concept by the provision in addition of the liner pipe.

[0058] Various modifications and improvements may be made without departing from the scope of the invention herein described. For example, in some variants an electrical conductor may instead be an optical fiber for data communication and/or sensing conditions in the tubing. A fluid conduit may be provided in place of an electrical conductor for conveying control fluid along the tubing e.g., for controlling a downhole valve or the like.

[0059] Changes and modifications in the specifically-described embodiments may be carried out without departing from the principles of the present invention, which is intended to be limited only by the scope of the appended claims as interpreted according to the principles of patent law including the doctrine of equivalents.