WO2018064766A1

WO2018064766A1 - Wire screen assembly and method therefor

Info

Publication number: WO2018064766A1
Application number: PCT/CA2017/051183
Authority: WO
Inventors: Mike Claerhout
Original assignee: Rgl Reservoir Management Inc.
Priority date: 2016-10-04
Filing date: 2017-10-04
Publication date: 2018-04-12
Also published as: AR109803A1

Abstract

A screen assembly for tubing string used in a wellbore comprises a base pipe, a screen covering the base pipe and end caps for securing the screen to the base pipe, the end caps being formed of two or more sections that are connected together when forming the assembly. A method of securing a screen to a base pipe comprises: providing the screen over the base pipe; providing end caps at each end of the screen, each end cap covering a portion of the screen and a portion of the base pipe, and each end cap comprising two or more sections; and, connecting the sections of the end cap together, thereby locating the screen on the base pipe.

Description

WIRE SCREEN ASSEMBLY AND METHOD THEREFOR CROSS REFERENCE TO PRIOR APPLICATIONS [0001] The present application claims priority under the Paris Convention from US Application Number 62/404,046, filed October 4, 2016, the entire contents of which are incorporated herein by reference. FIELD OF THE DESCRIPTION [0002] The present description relates to devices for use in screening particulate matter. In particular, the description relates to screens, more particularly, wire wrap screens, for use in subterranean hydrocarbon wells. BACKGROUND [0003] Hydrocarbons, such as oil, are obtained from subterranean reservoirs by drilling wells from the surface into such reservoirs, or formations, and subsequently providing production tubing within the well to allow the hydrocarbons to flow to the surface. Production tubing typically comprises a plurality of tubular members that are secured end to end forming a production or tubing string. The portion of the production tubing within the reservoir is provided with a number of ports along its length to allow inflow of hydrocarbons. [0004] In some cases, the reservoirs are found in "unconsolidated" formations, wherein the rock material is not cohesive. Wells in such formations are known to produce sand in addition to the desired hydrocarbons. The sand often collects in and plugs the ports provided in the tubing and/or plugs the interior of the tubing itself or other components forming part of the tubing string. In either case, the flow of hydrocarbons is impeded. The sand can also erode the tubing and/or other wellbore equipment. Further, the sand produced with the hydrocarbons, must be filtered out before processing the hydrocarbons, resulting additional costs and production delays. [0005] To mitigate against the above-noted problems, screens are generally used to filter out the sand at the reservoir, before it enters ports and/or the tubing. Such screens, such as "wire wrap screens", are provided over the ports on the tubing string. As known in the art, screens of this type comprise a base pipe that is adapted to be connected to other tubular members of the tubing string. The base pipe includes one or more ports and is covered by a screen component. The screen is generally of a tubular shape, having an inner diameter that is greater than the outer diameter of the base pipe. The screens are slid over the base pipe and, once positioned over the respective ports, they are secured in place to the base pipe. This generally involves welding the ends of the screen to the wall of the base pipe. [0006] While the above-noted welding method serves to secure the screen in place, the process also introduces one or more undesired artefacts. For example, due the heat of the welding process, the welded regions of the base pipe experience changes in their metallurgical properties. In some cases, the welded portions of the base pipe may lose their physical strength characteristics and become brittle. Although this change in physical properties may be reversed using an annealing procedure. This requires an additional manufacturing step (and associated cost and time) and, of course, the screen would also be subjected to such procedure, which may change its physical properties in an undesired manner. It is also known that the weld between the screen and the base pipe may become corroded or otherwise lose integrity when the pipe is in use. [0007] Various solutions have been suggested to attach screens to base pipes to avoid the need for welding. Examples of such prior attempts are discussed in the following references: US Patent Application US 2012/0073801 ; US Patent 5,931 ,232; US Patent 7,854,257; US Patent 8,267, 169; and, US Patent 8,281 ,854. While these prior methods avoid the use of welds, and therefore the above-noted problems, they introduce other issues such as longer manufacturing time and/or added cost. In some cases, the screen is secured by means of friction, which may not be effective when the tubing is in use downhole. [0008] A needs exists for an attachment method for securing a sand screen to a base pipe that addresses at least one of the aforementioned deficiencies. SUMMARY OF THE DESCRIPTION [0009] In one aspect, there is provided a screen assembly for a wellbore tubing section, wherein the screen is located on a base pipe by means of end caps, and without welding to the base pipe. [0010] In one aspect, there is provided a method of securing a screen, such as a wire screen, to a base pipe using a mechanical restraint as opposed to welds. In another aspect, there is provided a screen assembly comprising a base pipe and a screen. [0011] In one aspect, there is provided a method of securing a screen to a base pipe, wherein the method comprises: providing a screen over the base pipe; providing end caps at each end of the screen, each end cap covering a portion of the screen and a portion of the base pipe, the end cap comprising two or more sections; and, connecting the sections of the end cap together, thereby securing the screen to the base pipe without welding to the base pipe. [0012] Thus, in one aspect, there is provided a screen assembly comprising:

- a base pipe comprising one or more ports on the wall thereof and being adapted to be connected to tubular members of a tubing string;

- an annular screen provided coaxially over the base pipe and covering at least one of the ports, the screen having first and second ends;

- a first end cap adapted to locate the first end of the screen on the base pipe; and, - a second end cap adapted to locate the second end of the screen on the base pipe; wherein each of the first and second end caps comprises two or more sections that are connected together when provided on the base pipe. [0013] In another aspect, there is provided a method of securing a screen to a base pipe, the screen comprising an annular body and the base pipe comprising one or more ports in the wall thereof, the method comprising:

- providing the screen coaxially over the base pipe and locating the screen over at least one of the ports;

- providing end caps at each end of the screen, each end cap having a screen engaging portion, covering a portion of the screen, and a base pipe engaging portion, covering a portion of the base pipe, each end cap comprising two or more sections; and, - connecting the sections of the end cap together to locate the screen on the base pipe. BRIEF DESCRIPTION OF THE FIGURES [0014] The features of certain embodiments will become more apparent in the following detailed description in which reference is made to the appended figures wherein: [0015] Figure 1 is a partial cut-away side perspective view of a base pipe having a wire screen as known in the art. [0016] Figure 2 is an end view of the base pipe with wire screen of Figure 1. [0017] Figure 3 is a partial side cross-sectional view of the base pipe with wire mesh shown in Figure 1 . [0018] Figure 4 is a side perspective view of a portion of another base pipe and screen combination as known in the art. [0019] Figure 5 is a side cross-sectional view of a portion of a base pipe and screen combination according to one aspect of the description. [0020] Figure 6 is a side perspective view of a base pipe and screen combination according to one aspect of the description. [0021] Figure 7 is a side view of a base pipe according to one aspect of the description. [0022] Figure 8 is a side cross-sectional view of a base pipe and screen combination according to one aspect of the description. DETAILED DESCRIPTION [0023] As used herein, the term "wire screen" or "screen" will be understood to mean a screen that is used with base pipes that serves to screen out particulate material, such as sand, from entering ports provided on the base pipe. It will be understood that the filtering function will be limited to particles greater than or equal to a given size, depending upon the size of the openings provided on the screen. [0024] As used herein, the term "base pipe" will be understood as being a tubular member that is adapted to be connected to a tubing string or production string or other such tubular component that is used in subterranean wells for the production of hydrocarbons. While the present description is particularly suited for use in tubing associated with subterranean hydrocarbon wells, it will be understood that the description can also be adapted to any screen or screen assembly that is used on other piping or tubing

components. For example, the description can also be applicable for tubing used for water wells and the like. [0025] The terms "comprise", "comprises", "comprised" or "comprising" may be used in the present description. As used herein (including the specification and/or the claims), these terms are to be interpreted as specifying the presence of the stated features, integers, steps or components, but not as precluding the presence of one or more other feature, integer, step, component or a group thereof as would be apparent to persons having ordinary skill in the relevant art. [0026] Figures 1 to 3 schematically illustrate a known screen, in particular a wire wrap screen. As shown, a base pipe 10 includes one or more ports 16. Such ports may be provided circumferentially or in certain specific location along the circumference of the base pipe. Further, the ports 16 may be provided in discrete locations along the length of the base pipe. The base pipe 10 is provided with a number of ribs 12 that extend generally axially along the length of the base pipe. In the screen shown in Figures 1 to 3, a wire is wrapped over the ribs 12 to form a wire screen, or "wire wrap screen", 14. As shown, the wire forming the screen 14 is wrapped circumferentially over the ribs 12 and is wrapped in such a manner as to provide a desired or pre-determined spacing between each winding in order to allow the wire to act as a screen. As shown in Figure 1 , a wire wrap screen is typically attached to the base pipe 10 by means of a weld 18. It will be understood that a weld will also be provided on the opposite end (not shown) of the screen 14. [0027] Figure 4 illustrates another known screen, in particular a slotted screen 14a, comprising a slotted sheet that is wrapped around a base pipe 10a. In this version, the base pipe 10a may also be provided with ribs as described above (but not shown in Figure 4). Figure 4 also illustrates another known method of attaching a screen 14a to the base pipe 10a, which includes providing a housing, or cap 20, at each end of the screen 14a. The cap 20 comprises a generally ring-shaped structure that includes a first end that is adapted to extend over a portion of one end of the screen 14a. The first end of the cap 20 is secured to the screen 14a by means of a weld 17. The cap also includes a second end that is adapted to overlap a portion of the base pipe. The second end of the cap 20 is secured to the base pipe by means of a weld 19. [0028] As will be understood the welds such as 18 and 19 serve to secure the screen (such as a wire screen 14 or slotted screen 14a as described above) to the base pipe 10 or 10a. In this way, the screen is maintained in position over the ports 16 and is prevented from moving at least axially with respect to the base pipe. For example, during the procedure of running-in the tubing into a well, the screen 14, 14a would be subject to axial stresses due, for example, to contact with the wellbore. In addition, once in position, the high temperature subterranean environment may exert an axial force on the screen and/or the base pipe due to different thermal expansion properties of the base pipe and the screen. In these cases and others, the welds 18 and 19 serve to prevent movement of the screen with respect to the pipe. However, as discussed above, such welding procedures introduce potential deficiencies. [0029] Figures 5 and 6 illustrates one aspect of the present description, wherein a base pipe 100 is provided with a wire wrap screen 103, comprising a number of ribs 102 overlaid by a wire wrap 104. Such a screen 103 is similar to that shown in Figure 1. However, as shown in Figure 5, the screen 103 is not secured to the base pipe 100 by a weld. Instead, according to an aspect of the present description, there is provided a first housing, or first end cap 106 that is comprised of two or more sections that are adapted to be

circumferentially provided over the base pipe 100 in a "clamshell" format. For example, as shown in Figures 5 and 6, the end cap 106 is shown as comprising two sections, 107 and 109. In use, the two sections of the end cap 106 are positioned over the base pipe 100 and the wire wrap 104 of the screen 103. Once so positioned, the gaps between the sections 107 and 109 are permanently connected together by welds 1 16. As will be understood, the cap 106 can be formed with any number of sections as needed. Although a cap 106 with two sections is shown in Figure 6, the actual number of sections can vary based on, for example, the diameter of the base pipe or any other characteristic. Thus, the end cap 106 can be formed of 2, 3, 4, 5, 6, 7, 8 or more sections. For typical wellbore applications, an end cap having two sections would be preferred. However, the description is not limited to the number of sections forming the end cap 106. [0030] To further secure the end cap 106 to the base pipe 100, an arrangement such as shown in Figure 5 is used. In the illustrated example, the outer surface of the base pipe 100 is provided with one or more grooves, such as shown at 108 and 1 10. The grooves may, for example, be machined (such as with a lathe) or grinded (such as with an abrasive grinder or other such milling machine) into the wall of the base pipe 100. Although two grooves are shown in this example, it will be understood that any number of grooves may be provided. Correspondingly, the portions of the interior surface of the sections 107 and 109 of the end cap 106 that are to contact the base pipe 100 are provided with one or more ribs or protrusions, such as shown at 1 12 and 1 14 that are adapted to engage one or more of the grooves 108, 1 10. For example, in a preferred embodiment, when the sections of the end cap 106 are combined, the protrusions 1 12, 1 14 combine to form circumferential ribs on the inner diameter of the cap 20, wherein such ribs are adapted to be received within respective grooves 108 and 1 10 when the end cap 106 is installed on the base pipe 100. As can be seen in Figure 5, and as will be understood, once the end cap 106 is provided over the base pipe 100, and the sections (e.g. 107 and 109) of the end cap are welded together, the engagement of the ribs, 1 12 and 1 14, with the respective grooves, 108 and 1 10, serves to anchor the end cap 20, and therefore the screen 103, to the base pipe 100. In this way, the end cap is prevented from moving axially on the base pipe 100 and, therefore, serves the same purpose as the welds, such as those shown at 18 and 19 in Figures 1 and 4. As discussed above, by avoiding the use of welds on the base pipe, the above-noted problems or potential problems are avoided. In the above description, reference is made to the protrusions 1 12 and 1 14 forming circumferential ribs. Although such ribs may be continuous, the protrusions may comprise a plurality of independent protrusions with spaces there-between. In such case, the ribs would not be continuous; however, such ribs would still achieve the same purpose as discussed above. In some embodiments, the inner surface of the end cap 20 may be provided with a sealing member, such as an O-ring or the like, to aid in preventing fluids from passing underneath the cap when mounted on a base pipe. [0031] The end cap 106 may be secured to the wire wrap 104 of the screen 103 by a weld if necessary. Alternatively, the joint between the end cap 106 and the screen may be left open or may be sealed by any known means, such as with O-rings etc. [0032] Figures 7 and 8 illustrate another aspect of the present description, showing a base pipe 120, and a screen 121 formed by ribs 124 and a wire wrap 126. In this case, the base pipe 120 is provided with a single groove 122 instead of multiple grooves as described above. As shown, the single groove 122 may be wider than the previously described grooves. As shown in Figure 8, the sections forming the end cap 128 are, in turn, provided with a single rib, or protrusion, 130, which is adapted to be received within the groove 122. As with the previous description, when the sections of the end cap 128 are joined together, the individual protrusions 130 combine to form a circumferential rib on the inner diameter of the end cap 128. As discussed above, the rib may be continuous or comprised of a plurality of protrusions. In a manner similar to that discussed above, the engagement of the protrusions 130 within the groove 122 serves to axially anchor the end cap 128 to the base pipe. [0033] The advantage of using a single wide groove as shown in Figures 7 and 8 is primarily economic. That is, the provision of one wide groove is generally less time consuming than providing a number of smaller grooves. Further as illustrated in Figure 8, the circumferential rib provided on the end cap 128 need not occupy the entire space of the groove 122. Although this may result in some small amount of axial movement of the end cap 128 with respect to the base pipe 120, such movement would be limited by the boundary of the groove 122 and would not be problematic as long as the ports of the base pipe 120 remain covered by the screen. Thus, when providing a wide groove 122 on the base pipe 120 and allowing some clearance between the groove and the rib of the end cap 128, a greater sizing tolerance can be used when providing the groove. In other words, the groove may, for example by cut using a grinder rather than a more precise lathe. [0034] As discussed above, the end cap 128 shown in Figure 8 can be secured to the screen 121 by welding. Alternatively, the joint between the end cap 128 and the screen 121 may be left open or may be sealed such as with a sealing member (i.e. an O-ring) or the like. [0035] In general, the grooves provided in the base pipe may extend about 5 to 10% into the thickness of the base pipe wall. In this way, the grooves would not affect the integrity of the base pipe and would be within the tolerance limits under API specifications. [0036] In the above discussion, the end cap has been described as being formed of two or more sections that are separate and welded together when positioned over the base pipe and screen. However, in other aspects, the end cap sections may be partially connected together and include slots or other such openings cut therein, which can be expanded when installing over a base pipe. Once installed in the manner shown and discussed herein, the slots or openings can be welded together to form a unitary end cap body over the base pipe and screen combination. Alternatively, the end cap can be swaged using known methods so as to force the slots or openings to close. In this way, the end cap would be secured onto the base pipe and the screen without a further welding procedure being necessary. In another aspect, the pieces of the end cap may be hinged or otherwise connected at adjacent sides and coupled together when installed on a base pipe. It will be understood that the sections forming each end cap can be secured together by a variety of methods, some of which are discussed above. [0037] In the above description, reference has been made to one end cap; however, it will be understood that end caps are provided on opposite ends of the screen and, as such, each assembly or apparatus discussed herein will include two end caps provided on a base pipe. [0038] In the present description, reference has been made to wire screens. However, it will be understood that the present invention is not limited to wire screens and it may be used with slotted screens or any other screens known in the art. Thus, the term "screen" as used herein is intended to encompass a variety of known screens. [0039] Although the above description includes reference to certain specific

embodiments, various modifications thereof will be apparent to those skilled in the art. Any examples provided herein are included solely for the purpose of illustration and are not intended to be limiting in any way. Any drawings provided herein are solely for the purpose of illustrating various aspects of the description and are not intended to be drawn to scale or to be limiting in any way. The scope of the claims appended hereto should not be limited by the preferred embodiments set forth in the above description, but should be given the broadest interpretation consistent with the present specification as a whole. The disclosures of all prior art recited herein are incorporated herein by reference in their entirety.

Claims

WE CLAIM:

1. A screen assembly comprising:

- a first end cap adapted to locate the first end of the screen on the base pipe; and,

- a second end cap adapted to locate the second end of the screen on the base pipe; wherein each of the first and second end caps comprises two or more sections that are connected together when provided on the base pipe.

2. The screen assembly of claim 1 , wherein the first and second end caps are not welded to the base pipe.

3. The screen assembly of claim 1 or 2, wherein two or more sections of the end caps are connected together by welding.

4. The screen assembly of claim 1 or 2, wherein the two or more sections of the end caps are connected by a swaging operation.

5. The screen assembly of any one of claims 1 to 4, wherein each end cap includes a screen engaging portion and a base pipe engaging portion, the screen engaging portion having a larger internal diameter than the base pipe engaging portion.

6. The screen assembly of claim 5, wherein the base pipe engaging portions of the end caps are provided with one or more protrusions for engaging one or more corresponding grooves provided on the base pipe.

7. The screen assembly of claim 6, wherein the one or more protrusions comprise one or more circumferential ribs.

8. The screen assembly of claim 7, wherein the one or more circumferential ribs have a width that is smaller than the width of the corresponding grooves on the base pipe.

9. A method of securing a screen to a base pipe, the screen comprising an annular body and the base pipe comprising one or more ports in the wall thereof, the method comprising:

- providing end caps at each end of the screen, each end cap having a screen engaging portion, covering a portion of the screen, and a base pipe engaging portion, covering a portion of the base pipe, each end cap comprising two or more sections; and,

- connecting the sections of the end cap together to locate the screen on the base pipe.

10. The method of claim 9, wherein the end caps are not welded to the base pipe.

1 1 . The method of claim 9 or 10, wherein the step of connecting the sections of respective end caps together comprises welding.

12. The method of claim 9 or 10, wherein the step of connecting the sections of respective end caps together comprises swaging procedure.