CA3059902A1

CA3059902A1 - Linear tubular assist device and method

Info

Publication number: CA3059902A1
Application number: CA3059902A
Authority: CA
Inventors: Eldon D. Schelske
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-10-24
Filing date: 2019-10-24
Publication date: 2021-04-24

Abstract

A linear motor for use in the field of oil and gas, and more specifically to installation of tubulars in horizontal sections of oil and gas wells. A linear motor for moving a ferromagnetic object in a horizontal bore of a well. The linear motor having a hollow cylindrical casing and a conductive coil wrapped around the cylindrical casing. A cable electrically connected to the conductive coil is configured to energize the conductive coil to generate a magnetic field within the cylindrical casing. The magnetic field inducing motion of the ferromagnetic object along the cylindrical casing.

Description

LINEAR TUBULAR ASSIST DEVICE AND METHOD
FIELD
[0001] This invention is in the field of oil and gas, and more specifically to installation of tubulars in horizontal sections of oil and gas wells.
BACKGROUND
100021 In the oil and gas industries, coiled tubing refers to a long metal pipe in diameter which is supplied spooled on a large reel. The main benefits is the ability to push the coil tubing into the hole rather than relying on gravity.
SUMMARY
[0003] The aspects as described herein in any and/or all combinations. In an aspect, there is provided a linear motor for moving a ferromagnetic object in a horizontal bore of a well. The linear motor may comprise: a hollow cylindrical casing; a conductive coil wrapped around the cylindrical casing; a cable electrically connected to the conductive coil and configured to energize the conductive coil to generate a magnetic field within the cylindrical casing; and the magnetic field inducing motion of the ferromagnetic object along the cylindrical casing.
DESCRIPTION OF THE DRAWINGS
[0004] While the invention is claimed in the concluding portions hereof example embodiments are provided in the accompanying detailed description which may be best understood in

2 conjunction with the accompanying diagrams where like parts in each of the several diagrams are labeled with like numbers, and where:
100051 Figure 1 is a side cross-sectional view of a drill site;
100061 Figure 2 is a side view of a tubular assist device; and 100071 Figure 3 is a side cross-sectional view demonstrating an electrical configuration for the tubular assist device.
DETAILED DESCRIPTION
[0008] As shown in FIG. I, a side cross-sectional view of a drill site 100 is shown. The drill site 100 may comprise a drill rig 102, or other type of rig, such as for example a coiled tubing unit (not shown) or a workover/service rig (not shown), located above a bore 104 that has been drilled by a drill bit (not shown). The bore 104 extends down from the drill rig 102 in a vertical portion 106 to a heel 108 at which the bore 104 changed to a generally horizontal portion 110 to the toe (not shown) where the bore 104 ends. The bore 104 may comprise a casing 132 formed of concrete sections (not shown).
[0009] The casing 132 may receive coiled tubing 130 fed from the drill rig 102. The coiled tubing 130 may be pushed using a pushing force from the surface 308 to the toe of the bore 104.
The coiled tubing 130 may be sufficiently flexible for the coiled tubing 130 to bend such that the coiled tubing 130 may pass through the heel 108. At the end of the coiled tubing 130 may be a tool string 112. The tool string 112 may comprise bottom hole assemblies such as a mud motor and bit, jetting tool, cup tool, packers, and/or perforating guns. In this aspect, the tool string 112 may comprise a material responsive to a magnetic field, such as a ferromagnetic (e.g. iron,

3 carbon steel). In other aspects, the tool string 112 may comprise an electromagnet. In some aspects, the coiled tubing 130 may comprise the material responsive to the magnetic field and/or the electromagnet.
[0010] When the coiled tubing 130 contacts the casing 132, the coiled tubing 130 experiences friction. For example, if a section of the coiled tubing 130 is in tension when passing through a curved portion of the bore 104, such as the heel 108, the tension causes the coiled tubing 130 to be pushed against an inside of the curve. With increased tension, a radial load is greater pushing the coiled tubing 130 against the wall of the casing 132 resulting in friction. Similarly, when the coiled tubing 130 is in compression, the coiled tubing 130 is pushed against the outside curve also resulting in friction. When the coiled tubing 130 passes through the heel 108 in this manner, the friction forces may be known as a capstan effect.
100.11.1 When the coiled tubing 130 is pushed horizontally along the horizontal portion 110 of the bore 104, the pushing force required to push the coiled tubing 130 is equal to a total weight of the coiled tubing 130 and the tool string 112 in the casing 132 multiplied by a friction coefficient between the casing 132 and the coiled tubing 130. As the length of the coiled tubing 130 increases, the force required to overcome the friction force also increases.
When the pushing force exceeds a sinusoidal buckling load, the coiled tubing 130 starts to form a sinusoid within the casing 132 at the toe end.
[0012] When the coiled tubing 130 is continued to be pushed, a first portion of the coiled tubing 130 may continue to be straight in the casing 132 and a second portion will be lying in a sinusoid on the bottom of the casing 132. Once the pushing force exceeds a helical buckling load, the

4 coiled tubing 130 forms a helix portion within the casing 132. The helix causes additional wall contact forces that increases the friction between the coiled tubing 130 and the casing 132.
100131 As the coiled tubing 130 is pushed further into the bore 104, the helix portion of the coiled tubing 130 increases in length at the toe end. The increase in the helix portion results in increased wall contact forces resulting in a helical lockup where the coiled tubing 130 may be pushed no further into the bore 104 no matter how much axial force may be applied. The helical lockup may limit a maximum length of the horizontal portion 110.
[0014] Further details regarding calculating coiled tubing forces may be provided by "Basic Tubing Forces Model (TFM) Calculation" by Ken Newman & Kenneth Bhalla, CTES, L.P., published January 13, 1999, herein explicitly incorporated by reference in its entirety and updated in "Basic Tubing Forces Model (TFM) Calculation" by Ken Newmann, Kenneth Bhalla, and Albert McSpadden, CTES L.P., published October, 2003, herein explicitly incorporated by reference in its entirety.
100151 The problems associated with helical lockup are generally a result of the coiled tubing 130 being pushed from the surface 308. Some of the friction may be addressed through the use of lubricants between the coiled tubing 130 and the casing 132 of the bore 104. In some aspects, lubricants may be insufficient, expensive, and/or unsuitable 100161 In this example, one or more linear motors 120, 122 may be placed along the horizontal portion 110 of the bore 104. The linear motors 120, 122 may provide a motive force to the coiled tubing 130 and/or the tool string 112. The motive force may pull on the toe end of the coiled tubing 130 causing the coiled tithing 130 to maintain a straight configuration within the

5 casing 132 and thereby reducing a probability of helical lockup and/or frictional forces between the casing 132 and the coiled tubing 130.
100171 Turning to FIG. 2, a linear motor 200 may comprise a section 240 of casing 132 constructed of concrete, carbon steel, or similar material. The linear motor 200 may be constructed by using a joint of the production casing 132. Once installed in the well, the casing 132 may be cemented in place. The cementing of the casing 132 may be performed by pumping a cement slurry through the casing 132 and displacing fluid until an annulus between the casing 132 and the well bore wall is full of cement. Once this operation is completed the linear motor 200 may be permanently installed in the well. In some aspects, the cement may comprise thermal cement in order to prevent degradation over time due to heat produced by the linear motor 200.
[0018] After installation, the section 240 may comprise a cylinder having a generally hollow interior 202 for receiving the coiled tubing 130. In some aspects, the diameter of the section 240 may comprise casing diameters selected from 4.1/2, 5.1/2', and 7". The section 240 may comprise a threaded end 260 where the threads are on the exterior of the section 240 for screwing the section 240 into other sections of casing 132. Opposite the threaded end 260 may be a coupler 250 configured to receive the threaded end of other sections of casing 132. In this aspect, the coupler 250 may be threaded on the interior of the section 240.
[0019] A conductive coil 230 may be wrapped around the section 240 of casing 132. In this aspect, the conductive coil 230 may be a copper material or any other type of conductor, although copper may be the most cost-effective conductor. A maximum thickness of the coil 230 may be equal to the outer diameter of the particular casing's coupling.
For example, a 5.1/2"

6 casing may have a thickness of 1" and therefore, the thickness of the coil 230 may be less than or equal to 1". The conductive coil 230 may be covered with an insulating coating 230 electrically insulating the conductive coil 230 from the bore 104. In this aspect, the coating 230 may comprise a polyurethane material to protect the coil windings as the conductive coil 230 is .. installed into the well. The conductive coil 230 may be electrically connected to a cable connection 210 on the coupler end 250 of the section 240. The cable connection 210 may have a positive and a negative/ground terminal.
[0020] Turning to FIG. 3, a cable 302 comprising at least two electrical lines, one for ground and one for power (not shown) may be run along the exterior of the casing 132 and may be banded to the exterior of the casing 132. The electrical cables 302 run from the surface 308 to the cable connection 210 on the linear motor 200 forming an electrical circuit. In some aspects with more than one linear motor 200, the cable 302 may comprise a control line (not shown) that may communicate a signal to activate a relay (or similar electrical device) 312 associated with each of the linear motors 200. When a particular relay 312 becomes activated, the linear motor 200 associated with the relay 312 passes current through the linear motor 200. In some aspects, each linear motor 200 may be installed at least 1000-m apart. The cable 302 may then continue on to the relay 312 of the next linear motor 310.
[0021] When the conductive coil 230 is energized using the pair of electrical lines, a magnetic field may be induced within the center of the coil 230. Since the tool string 112 may comprise .. the magnetic responsive material, the magnetic field may induce motion of the tool string 112.
For example, when the current flows in one direction through the coil 230, the magnetic field generated pulls on the tool string 112 in one direction. When the current flows in the opposite direction through the coil 230, the magnetic field generated pulls on the tool string 112 in the

7 opposite direction. An amount of current required to move the magnetic responsive material may be determined based, in part, on the casing size, length of cable, the size of the linear motor 200, and/or a combination thereof. A plurality of linear motors 200 may be placed adjacent to each other and turned on sequentially in order to further accelerate the tool string 112 in one direction or another. The pulling of the tool string 112 may alleviate problems associated with the helical lockup of the coiled tubing 130 by pulling on the end of the coiled tubing 130 reducing sinusoidal buckling and/or helical buckling.
[0022] To use and control the linear motor 200, an electrical generator 304 and a Variable Frequency Drive 306 may be connected to the cable at the surface 308. The VFD
306 may control a frequency, a duration, the current, and/or a direction of the motive force on the tool string 112 and/or coiled tubing 130 passing within the linear motor 200.
[0023] To install the linear motor 200, the section 240 may be threaded into other sections of the casing 132 forming a casing string. The casing string may be landed past the heel 108 of the well 100 in the horizontal section 110. Once the casing string has been landed, cementing of the casing string may take place. A casing slip and seal assembly (not shown) may then be installed and the electrical cable may be routed out of a port in a tubing hanger section (not shown) of the wellhead 102.
[0024] Although the aspects described herein demonstrate the linear motor 200 acting on the tool string 112, other aspects may have the linear motor 200 acting on the coiled tubing 130, tubulars, telemeters, and/or other downhole tools.
100251 The dimensions depicted in the figures may not be to scale. Certain features may have been exaggerated in order to facilitate identification.

8 10026] The foregoing is considered as illustrative only of the principles of the invention.
Further, since numerous changes and modifications will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all such suitable changes or modifications in structure or operation which may be resorted to are intended to fall within the scope of the claimed invention.

Claims

What is claimed is:

1, A
linear motor for moving a ferromagnetic object in a horizontal bore of a well, the linear motor comprising:
a hollow cylindrical casing;
a conductive coil wrapped around the cylindrical casing;
a cable electrically connected to the conductive coil and configured to energize the conductive coil to generate a magnetic field within the cylindrical casing; and the magnetic field inducing motion of the ferromagnetic object along the cylindrical casing.