EXPANSION APPARATUS

Abstract

An expansion apparatus and a method of manufacturing an expansion apparatus are provided. The expansion apparatus comprises an expandable element having a monolithic wall structure circumscribing a longitudinal axis and enclosing a space for receiving a pressurised fluid for use in inflating the expandable element between a non-expanded configuration and an expanded configuration. The wall structure is formed by additive manufacturing to have an initial non-expanded profile in which a perimeter length of the wall structure is greater than an outer gauge perimeter of the wall structure. Expansion during inflation is achieved by reforming the initial non-expanded profile of the wall structure to increase the outer gauge perimeter.

Claims

1. An expansion apparatus comprising: an expandable element having a monolithic wall structure circumscribing a longitudinal axis and enclosing a space for receiving a pressurised fluid for use in inflating the expandable element between a non-expanded configuration and an expanded configuration; the wall structure being formed by additive manufacturing to have an initial non-expanded profile in which a perimeter length of the wall structure is greater than an outer gauge perimeter of the wall structure, wherein expansion during inflation is achieved by reforming the initial non-expanded profile of the wall structure to increase the outer gauge perimeter.

2. The expansion apparatus of claim 1, wherein the perimeter length of the wall structure varies along the longitudinal axis.

3. The expansion apparatus of claim 1, wherein the wall structure comprises: a first perimeter length at a first axial location; a second perimeter length at a second axial location; and a third perimeter length at a third axial location which is intermediate the first and second axial locations, wherein the third perimeter length is greater than the first and second perimeter lengths.

4. (canceled)

5. The expansion apparatus of claim 3, wherein: a first flank angle is formed between the longitudinal axis and a line connecting the first axial location and the third axial location, a second flank angle is formed between the longitudinal axis and a line connecting the second axial location and the third axial location, and the first and second flank angles are equal.

6. The expansion apparatus of claim 1, wherein an inner perimeter length of the wall structure varies along the longitudinal axis.

7. The expansion apparatus of claim 1, wherein the wall structure comprises: a first inner perimeter length at a first axial location; a second inner perimeter length at a second axial location; and a third inner perimeter length at a third axial location which is intermediate the first and second axial locations, wherein the third inner perimeter length is greater than the first and second inner perimeter lengths.

8. (canceled)

9. The expansion apparatus of claim 1, wherein the wall structure comprises: a first section; a second section; and a third section, the third section being longitudinally intermediate the first and second sections.

10. The expansion apparatus of claim 9, wherein the wall structure has a greater thickness at a transition area between the first and third sections and/or between the third and second sections.

11. The expansion apparatus of claim 9, wherein the outer gauge perimeter at least one increases or decreases through the first and/or second sections, and remains constant through the third section.

12. (canceled)

13. The expansion apparatus of claim 1, wherein the expandable element is hollow, longitudinally asymmetric, substantially inelastic, or combinations thereof.

14. (canceled)

15. (canceled)

16. The expansion apparatus of claim 16, wherein the wall structure comprises folds, and wherein the folds are circumferentially distributed.

17. (canceled)

18. The expansion apparatus of claim 16, wherein at least one of the folds define a generally serpentine cross-section in a circumferential direction, and the folds extend longitudinally.

19. (canceled)

20. The expansion apparatus of claim 16, wherein each fold has an associated depth and the fold depth varies along the longitudinal axis of the wall structure, or wherein each fold has a generally arcuate section with axially extending sections extending from end thereof.

21. (canceled)

22. The expansion apparatus of claim 1, further comprising a layer surrounding the wall structure, the layer configured to create a seal in the expanded configuration.

23. (canceled)

24. A computer program comprising computer executable instructions that, when executed by a processor, cause the processor to control an additive manufacturing apparatus to manufacture the expansion apparatus of claim 1.

25. A method of manufacturing an expansion apparatus via additive manufacturing, the method comprising: obtaining an electronic file representing a geometry of the expansion apparatus of claim 1; and controlling an additive manufacturing apparatus to manufacture, over one or more additive manufacturing steps, the expansion apparatus according to the geometry specified in the electronic file.

26. A method of providing a seal, the method comprising: locating the expansion apparatus of claim 1 in a wellbore; and inflating the expansion apparatus in the wellbore to provide a seal.

27. The method of claim 26, wherein inflating further comprises increasing the outer gauge perimeter of the wall structure of the expansion apparatus.

28. The method of claim 26, wherein inflating further comprises providing a seal with a surface of the expansion apparatus or a sleeve surrounding the expansion apparatus.

29. (canceled)

30. A method of manufacturing an expansion apparatus, the method comprising: forming, by additive manufacturing, an expansion apparatus comprising an expandable element having a monolithic wall structure circumscribing a longitudinal axis and enclosing a space for receiving a pressurised fluid for use in inflating the expandable element between a non-expanded configuration and an expanded configuration, the wall structure having an initial non-expanded profile in which a perimeter length of the wall structure is greater than an outer gauge perimeter of the wall structure, wherein the initial non-expanded profile is reformable by inflation to increase the outer gauge perimeter.

31. (canceled)

32. (canceled)

Description

BRIEF DESCRIPTION OF THE FIGURES

[0173] A description is now given, by way of example only, with reference to the accompanying drawings, in which:

[0174] FIG. 1 is a perspective view of an expansion apparatus illustrated in a non-expanded configuration;

[0175] FIGS. 2A to 2C are sequential perspective views of the expansion apparatus of FIG. 1 being formed through an additive manufacturing process;

[0176] FIG. 3 is a perspective view of an axial segment of the expansions apparatus of FIG. 1;

[0177] FIG. 4 is a perspective view of the expansion apparatus of FIG. 1 illustrated in an expanded configuration;

[0178] FIG. 5A to 5C are elevation sectional views of alternative forms of an expansion apparatus taken along the longitudinal axis in non-expanded configurations;

[0179] FIG. 6A is a perspective view of an alternative form of an expansion apparatus in a non-expanded configuration;

[0180] FIG. 6B is an elevation sectional view of the expansion apparatus of FIG. 6A taken along the longitudinal axis;

[0181] FIGS. 7A to 7C are sequential perspective views of the expansion apparatus of FIG. 6A being formed through an additive manufacturing process;

[0182] FIG. 8A is a perspective view of an expansion apparatus with a sleeve;

[0183] FIG. 8B is a perspective sectional view of the expansion apparatus of FIG. 8A taken along the longitudinal axis;

[0184] FIG. 9A is a perspective view of an expansion apparatus in an expanded configuration;

[0185] FIG. 9B is a sectional elevation view of the expansion apparatus of FIG. 9A;

[0186] FIG. 9C is a perspective elevation view the expansion apparatus of FIG. 9A with a sleeve;

[0187] FIG. 10 is a perspective view of a tool string comprising an expansion apparatus;

[0188] FIG. 11A is a perspective view of an expansion apparatus in an expanded configuration;

[0189] FIG. 11B is an elevation view of the expansion apparatus of FIG. 11A;

[0190] FIG. 12A is a perspective view of an expansion apparatus in an expanded configuration on a pipe;

[0191] FIG. 12B is an elevation sectional view of the expansion apparatus and pipe of FIG. 12A taken along the longitudinal axis;

[0192] FIG. 12C is an elevation sectional view of the expansion apparatus and a pipe of FIG. 12A taken along the longitudinal axis;

[0193] FIG. 13A is a perspective view of an expansion apparatus in an expanded configuration having a slip and on a pipe;

[0194] FIG. 13B is an elevation sectional view of the expansion apparatus having the slip on the pipe of FIG. 13A; and

[0195] FIG. 14 is a perspective view of an axial segment of an expansions apparatus.

DESCRIPTION OF SPECIFIC EMBODIMENTS

[0196] The foregoing summary, as well as the following detailed description of certain embodiments will be better understood when read in conjunction with the accompanying drawings. As will be appreciated, like reference characters are used to refer to like elements throughout the description and drawings. As used herein, an element or feature recited in the singular and preceded by the word “a” or “an” should be understood as not necessarily excluding a plural of the elements or features. Further, references to “one example” or “one embodiment” are not intended to be interpreted as excluding the existence of additional examples or embodiments that also incorporate the recited elements or features of that one example or one embodiment. Moreover, unless explicitly stated to the contrary, examples or embodiments “comprising”, “having” or “including” an element or feature or a plurality of elements or features having a particular property might further include additional elements or features not having that particular property. Also, it will be appreciated that the terms “comprises”, “has” and “includes” mean “including but not limited to” and the terms “comprising”, “having” and “including” have equivalent meanings.

[0197] As used herein, the term “and/or” may include any and all combinations of one or more of the associated listed elements or features.

[0198] It will be understood that when an element or feature is referred to as being “on”, “attached” to, “connected” to, “coupled” with, “contacting”, etc. another element or feature, that element or feature may be directly on, attached to, connected to, coupled with or contacting the other element or feature or intervening elements may also be present. In contrast, when an element or feature is referred to as being, for example, “directly on”, “directly attached” to, “directly connected” to, “directly coupled” with or “directly contacting” another element of feature, there are no intervening elements or features present.

[0199] It will be understood that spatially relative terms, such as “under”, “below”, “lower”, “over”, “above”, “upper”, “front”, “back” and the like, may be used herein for ease of describing the relationship of an element or feature to another element or feature as depicted in the figures. The spatially relative terms may however, encompass different orientations in use or operation in addition to the orientation depicted in the figures.

[0200] Reference herein to “example” means that one or more feature, structure, element, component, characteristic and/or operational step described in connection with the example is included in at least one embodiment and or implementation of the subject matter according to the present disclosure. Thus, the phrases “an example,” “another example,” and similar language throughout the present disclosure may, but do not necessarily, refer to the same example. Further, the subject matter characterizing any one example may, but does not necessarily, include the subject matter characterizing any other example.

[0201] Reference herein to “configured” denotes an actual state of configuration that fundamentally ties the element or feature to the physical characteristics of the element or feature preceding the phrase “configured to”.

[0202] Unless otherwise indicated, the terms “first,” “second,” etc. are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to a “second” item does not require or preclude the existence of lower-numbered item (e.g., a “first” item) and/or a higher-numbered item (e.g., a “third” item).

[0203] As used herein, the terms “approximately” and “about” represent an amount close to the stated amount that still performs the desired function or achieves the desired result. For example, the terms “approximately” and “about” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, or within less than 0.01% of the stated amount.

[0204] Some of the following examples have been described specifically in relation to well infrastructure relating to oil and gas production, or the like, but of course the systems and methods may be used with other well structures. Similarly, while in the following example an offshore well structure is described, nevertheless the same systems and methods may be used onshore, as will be appreciated.

[0205] Aspects of the present disclosure relate to an expansion apparatus which may be used in a wellbore. It should be understood that the drawings presented are not to scale, and may not reflect actual dimensions, ratios, angles, numbers of features or the like.

[0206] A perspective view of an expansion apparatus 100 is shown in FIG. 1, in an initial non-expanded configuration. Although any use may be made of the apparatus 100, in the present example the expansion apparatus 100 is for use in a downhole environment to provide a seal. The expansion apparatus 100 comprises an expandable element 102 having a monolithic wall structure circumscribing a longitudinal axis A-A. The wall structure has an initial non-expanded profile as illustrated in FIG. 1 in which a perimeter length of the wall structure is greater than an outer gauge perimeter of the wall structure.

[0207] The outer gauge perimeter is defined by the outer envelope of the wall structure. The outer envelope envelops, completely encloses or enfolds the wall structure as if with a covering.

[0208] The perimeter length of the wall structure is defined by tracing the outer surface of folds 106 which form the monolithic wall structure. In the non-expanded profile illustrated in FIG. 1, the perimeter length is greater than the outer gauge diameter. As will be described in more detail bellow, the expansion apparatus 100 having a perimeter length which is greater than the outer gauge diameter is provided by additive manufacturing. In this respect, it should be understood that the term “fold” is used herein for convenience and simplicity in describing the geometry of the illustrated wall structure when in the initial non-expanded configuration, and is not intended to impart any limitation as to the method used to form this folded geometry. That is, the term “fold” is directed to the wall geometry, and not a folding forming process.

[0209] The folds 106 are distributed circumferentially and each fold 106 spans a length of the wall structure. As shown in FIG. 1, the depth of the folds 106 increases through a first section 110 of the expansion apparatus to a third section 114, and increases through a second section 112 to the third section 114. The depth of the folds 106 remains constant in the third section 114. A shown in FIG. 1, each individual fold spans the first, second and third sections 110, 112, 114, respectively. The outer gauge perimeter increases from one longitudinal end of the expandable element 102 through the first section 110 to the third section 114. The outer gauge perimeter remains constant through the third section 114. The outer gauge perimeter increases from the other longitudinal end of the expandable element 102 through the second section 112 to the third section 114.

[0210] The expansion apparatus 100 further comprises connectors 108 associated with each longitudinal end of the expansion apparatus 100. The connectors 108 are affixed to the ends of the expansion apparatus 100. While not shown in FIG. 1, the connectors 108 are hollow allowing for fluid to be delivered into a space enclosed by the wall structure. The connectors 108 are configured to connect to other downhole elements such as a tubing, tool string, production string, running string, drill string, etc. One or both of the connectors 108 may be formed integrally with the wall structure, or alternatively may be separately formed and secured thereto.

[0211] As noted above, the wall structure of the expandable element 106 is formed by additive manufacturing, which is sequentially exemplified in FIGS. 2A to 2C. As illustrated in FIG. 2A, a processor 8 receives a design file or CAD file 6 of the expansion apparatus 100 to be manufactured by a print head 10 of an additive manufacturing printer. The print head 10 is communicatively connected to the processor 8. The processor 8 may include any suitable memory or storage device such as random-access memory (RAM), static RAM (SRAM), dynamic memory (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM) or Flash memory useable to store one or more design files 6. The design file 6 may be physically stored in the memory of the processor 8. The design file 8 may be translated between different formats to generate computer readable instructions or code to operate the processor 8 to control the print head 10 such that the print head 10 manufactures, via additive manufacturing, the expansion apparatus 100 specified in the design file 8. While the processor 8 and design file 6 have been illustrated in FIG. 2A, they are also present in FIGS. 2B and 2C, but have been omitted for clarity.

[0212] The print head 10 dispenses print material 12. Layers of the wall structure are added to directly form the initial non-expanded profile of the wall structure. The wall structure encloses a space 104 for receiving a pressurised fluid for use in inflating the expandable element 102 between a non-expanded configuration and an expanded configuration. The print head 10 initially forms the first section 110. The print head 10 dispenses print material such that the first section 110 has an increasing perimeter length and an increasing outer gauge perimeter. The print head 10 then forms the third section 114 as shown in FIG. 2B which may have a different perimeter length and thickness than the first section 110. The print head 10 dispenses print material 12 to form the third section 114 having a constant perimeter length and a constant outer gauge perimeter. The print head 10 then forms the second section 112 as shown in FIG. 2C which may have a different perimeter length and thickness than the first and third sections 110, 114. The print head 10 dispenses print material 12 to form the second section 112 having a decreasing perimeter length and a decreasing outer gauge perimeter. In the illustrated arrangement, the print head 10 dispenses print material 12 such that the perimeter length and outer gauge perimeter of second section 112 decrease at the same rate which the perimeter length and outer gauge perimeter of first section 110 increase at. The print head 10 may also form the connectors 108.

[0213] An axial segment of the expansion apparatus 100 is shown in FIG. 3. In the illustrated arrangement, the folds 106 have a generally serpentine shape which span the circumference of the expansion element 102.

[0214] The folds 106 generally have a radially tortuous or serpentine path. Each fold 106 comprise an arcuate section with sections extending from either end of the arcuate section.

[0215] The folds 106 define peaks 20 with a trough 22 between adjacent peaks 20. Each peak and each trough 22 is generally rounded. Each peak 20 has a generally tear drop shape such that each peak 20 defines a pocket 24. The sidewalls of the wall structure of a peak 20 define the pocket 24. The sidewalls of the peak 20 are almost in contact to define the pocket 24. One or more of the pockets 24 may expand upon inflation of the expandable element 102. Altering the shape, dimension and configuration of one or more of the peaks 20, trough 24 and pockets 24 may alter the inflation profile of the expansion apparatus.

[0216] Manufacturing the wall structure of the expandable element 102 allows for the folds 106 to have a complex geometries that enable a greater ratio of the perimeter length to the outer gauge perimeter than possible with apparatus manufactured by conventional subtractive manufacturing techniques. Folds 106 with complex geometries, such as the folds 106 illustrated in FIG. 3, allow for a greater perimeter length to be provided in a a particular outer gauge perimeter than is possible with conventional subtractive manufacturing techniques. More folds 106 and/or a greater perimeter length are accordingly packaged in the outer gauge perimeter in the non-expanded configuration such that a greater expansion ratio is achieved upon inflation of the expandable element 102.

[0217] In the illustrated arrangement, a sidewall of the peaks 20 and troughs 22 has a constant thickness. Furthermore, the sidewalls of the peaks 20 and troughs 22 are coplanar. One of skill in the art will appreciate, that this may be varied depending on the application and environment of use of the expansion apparatus 100.

[0218] In the illustrated arrangement, each peak 20 is centred about a radial line of the expandable element 102. Accordingly, a radial line extending from the radial centre of the expandable element 102 bisects each peak 20 and trough 22. An exemplary radial line is indicated as L in FIG. 3. While each of the folds 106 has been illustrated as having a similar profile or configuration, each fold 106 may have a different profile or configuration. The configuration or profile of the folds 106 may vary around the circumference of the wall structure.

[0219] The expansion apparatus 100 is illustrated in an expanded configuration in FIG. 4. The expandable element 102 has been inflated by fluid pressure and the initial non-expanded profile has been reformed to increase the outer gauge perimeter. The expansion apparatus 100 is located within a structure 150. Exemplary structures include wellbore casing, tubing and piping. While an outer surface of the expandable apparatus 102 has been shown without folds 106, one of skill in the art will appreciate that folds 106 may still be present in the expansion apparatus 100 after inflation. The expansion apparatus 100 may be configured such that a portion of the outer surface is in contact with a portion of the structure upon inflation of the expandable element 102.

[0220] As best shown in FIG. 5A, the inner gauge perimeter is non-constant through the longitudinal axis A-A of the expansion apparatus 100. The inner gauge perimeter decreases from one longitudinal end of the expandable element 102 through the first section 110. The inner gauge perimeter decrease from the other longitudinal end of the expandable element 102 through the second section 112. The inner gauge perimeter remains constant through the third section 114.

[0221] As further shown in FIG. 5A, the wall structure of the expandable element 102 has a first flank angle 120 and a second flank angle 122. The first flank angle 120 is formed between a first axial location at one longitudinal end of the expansion apparatus 100 proximate the first section 110 and the longitudinal axis A-A. The second flank angle 122 is formed between a second axial location at the other longitudinal end of the expansion apparatus 100 proximate the second section 122 and the longitudinal axis A-A. The flank angles 120, 122 are equal. In this exemplary expansion apparatus 100, the flank angles 120, 122 are greater than zero.

[0222] As shown in FIG. 5A, the connectors 108 are configured for connection to other downhole elements. While not shown, the connectors 108 may have inner or outer threads for connection.

[0223] The outer gauge perimeter indicated by dashed lines in FIG. 5A, respectively, increases through the first and second sections 110, 112, respectively. In particular, the outer gauge perimeter increases through the first section 110 to the third section 114. Similarly, the outer gauge perimeter increases through the second section 112 to the third section 114. The outer gauge perimeter may say constant in the third section 114. Expansion during inflation of the expandable element is achieved by reforming the initial non-expanded profile of the wall structure to increase the outer gauge perimeter.

[0224] Other forms of the expansion apparatus 100 are shown in FIGS. 5B and 5C. As shown in FIGS. 5A and 5B, the flank angle 120, 122 may be varied resulting in different profiles for the expandable element 102. The flank angle 120, 122 may be less than zero as illustrated in FIG. 5B. Also, as illustrated in FIG. 5B, the outer gauge perimeter may decrease through the first section 110, stay constant in the third second 114 and increase through the second section 112 when moving longitudinally along the expansion element.

[0225] As illustrated in FIG. 5C, the outer gauge perimeter may vary between the sections 110, 114, 112, and the thickness of the folds 106 of the wall structure may vary through the sections 110, 114, 112. In the first section 110, the thickness of the wall structure increases such that an inner gauge perimeter of the first section 110 decreases while the outer gauge perimeter increases moving in the longitudinal direction. The inner gauge perimeter may be defined by an inner envelope of the wall structure. The inner and outer gauge perimeters may remain constant through the third section 114 of the wall structure. The inner gauge perimeter may increase while the outer gauge perimeter may decrease through the second section 112. While only certain alternatives of the expansion apparatus 100 have been illustrated, one of skill in the art will appreciate that various inner and outer gauge perimeters are possible by varying wall structure thickness and flank angles of the sections 110, 114, 112.

[0226] In the expansion apparatus 100 depicted in FIGS. 1 to 4, the thickness and the outer gauge perimeter of the wall structure of the expandable element 102 is non-constant or non-uniform. However, the skilled reader will appreciate that other configurations are possible.

[0227] An expansion apparatus 200 is shown in FIGS. 6A and 6B. The expansion apparatus 200 is similar to the described expansion apparatus 100 shown in FIGS. 1 to 5 and as such like elements are referred to with the same reference numerals, incremented by 100. The expansion apparatus 200 comprises an expandable element 202 having a monolithic wall structure circumscribing a longitudinal axis B-B.

[0228] In contrast with the expansion apparatus 100, the outer gauge perimeter indicated by dashed lines in FIG. 6B of wall structure remains constant through the sections 210, 212, 214. The expansion apparatus 200 may be particularly suitable for run through applications where a constant outer diameter allows the expansion apparatus 200 to pass through tight or narrow downhole restricted areas within a wellbore.

[0229] While the outer gauge perimeter remains constant, the inner gauge perimeter does not. The Inner gauge diameter decreases from one longitudinal end of the expandable element 202 through the first section 210 to the third section 214. The inner gauge perimeter decreases from the other longitudinal end of the expandable element 202 through the second section 212 to the third section 214. The inner gauge perimeter remains constant or uniform through the third section 214.

[0230] As illustrated in FIG. 6B, the wall structure of the expandable element 202 has a first flank angle 220 and a second flank angle 222. The first flank angle 220 is formed between a first axial location at one longitudinal end of the expansion apparatus 200 proximate the first section 210 and the longitudinal axis B-B. The second flank angle 222 is formed between a second axial location at the other longitudinal end of the expansion apparatus 200 proximate the second section 222 and the longitudinal axis B-B. The flank angles 220, 222 are equal. In this exemplary expansion apparatus 200, the flank angles 220, 222 are less than zero, i.e. negative angles relative to the longitudinal axis B-B.

[0231] Expansion during inflation of the expandable element 202 is achieved by reforming the initial non-expanded profile of the wall structure to increase the outer gauge perimeter.

[0232] As shown in FIGS. 7A to 7C, the expansion apparatus 200 is formed by additive manufacturing, which is sequentially exemplified in FIGS. 7A to 7C. As illustrated in FIG. 7A, a processor 8 receives a design file or CAD file 6 of the expansion apparatus 200 to be manufactured by a print head 10 of an additive manufacturing printer. The print head 10 is communicatively connected to the processor 8. The processor 8 may include any suitable memory or storage device such as random-access memory (RAM), static RAM (SRAM), dynamic memory (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM) or Flash memory useable to store one or more design files 6. The design file 6 may be physically stored in the memory of the processor 8. The design file 8 may be translated between different formats to generate computer readable instructions or code to operate the processor 8 to control the print head 10 such that the print head 10 manufactures, via additive manufacturing, the expansion apparatus 200 specified in the design file 8. While the processor 8 and design file 6 have been illustrated in FIG. 7A, they are also present in FIGS. 7B and 7C, but have been omitted for clarity.

[0233] The print head 10 dispenses print material 12. Layers of the wall structure are added to directly form the initial non-expanded profile of the wall structure. The wall structure encloses a space 204 for receiving a pressurised fluid for use in inflating the expandable element 202 between a non-expanded configuration and an expanded configuration. The print head 10 initially forms the first section 210. The print head 10 dispenses print material such that the first section 210 has an increasing perimeter length, a constant outer gauge perimeter and a decreasing inner gauge perimeter. The print head 10 then forms the third section 214 as shown in FIG. 7B which may have a different perimeter length and thickness than the first section 210. The print head 10 dispenses print material 12 to form the third section 214 having a constant perimeter length, a constant outer gauge perimeter and a constant inner gauge perimeter. The print head 10 then forms the second section 212 as shown in FIG. 7C which may have a different perimeter length and thickness than the first and third sections 210, 214. The print head 10 dispenses print material 12 to form the second section 212 having a decreasing perimeter length, a constant outer gauge perimeter and an increasing inner gauge perimeter. In the illustrated arrangement, the print head 10 dispenses print material 12 such that the inner gauge perimeter of second section 212 increases at the same rate which the inner gauge perimeter of first section 210 decreases at. The print head 10 may also form the connectors 208.

[0234] The described expansion apparatus may be used create a seal with a surface. As shown in FIGS. 8A and 8B, a sleeve 240 may surround the expansion apparatus 100. The sleeve 240 may be used to create a seal with a surface. In particular, upon inflation of the expansion apparatus from the non-expanded configuration to the expanded configuration, the sleeve may contact a surface to create a seal. While the sleeve 240 has been shown with the expansion apparatus 100, the skilled reader will appreciate that the sleeve 240 may be used with any of the expansion apparatus described herein. In the illustrated arrangement, the sleeve 240 is an elastomer. The described sleeve 204 could be used with any of the expansion apparatus described herein.

[0235] The sleeve 240 is generally positioned to surround the third section 114 of the expandable element 102. In this example, the sleeve 240 has a ribbed outer surface configured to provide a seal with an outer surface upon expansion through inflation of the expandable element 102.

[0236] While a sleeve 240 has been described, one of skill in the art will appreciate that other configurations are possible. The sleeve 240 may be used in addition to or as alternative to a coating, layer, shroud or similar. Furthermore, no sleeve 240 may be used.

[0237] Turning now to FIGS. 9A to 9C, an expansion apparatus 300 is illustrated in the expanded configuration. The expansion apparatus 300 is similar to the described expansion apparatus 100 shown in FIGS. 1 to 4 and as such like elements are referred to with the same reference numerals, incremented by 200. The expansion apparatus 300 comprises an expandable element 302 having a monolithic wall structure circumscribing a longitudinal axis C-C. The expansion apparatus 300 further comprises base collar 352 and anti-extrusion arrangement 350. The base collar 352 is affixed to an end of the expandable element 302. The base collar 352 may allow fluid pressure, e.g. fluid flowing to the volume defined by the expandable element, to expand the expandable to the expanded configuration.

[0238] The anti-extrusion arrangement 350 is configured to provide a support function to minimise extrusion of the expansion apparatus 300. In the illustrated arrangement, the anti-extrusion arrangement 350 comprises petals or fingers 356 overlaying an inflatable component 358. The fingers 356 are configured to provide axial rigidity to the expansion apparatus 300. In the initial non-expanded configuration of the expandable element 302, the fingers 356 overlay the element 302 such that fingers 356 abut or are proximate each other. The fingers 356 may be interlocked in the non-expanded configuration. In the non-expanded configuration, the envelope defined by the fingers 356 is generally the same as the outer gauge perimeter of the expansion apparatus 300. As the element transitions to the expanded configuration, the fingers 356 separate as the expandable element 302 inflates or expands the inflatable component 358. In the expanded configuration, the fingers 356 and/or inflatable component 358 may assist in providing the support function. As illustrated in FIG. 9C, a sleeve may be positioned over the inflatable component 358 between the fingers 356 of the anti-extrusion arrangement 350. The sleeve 360 may assist in providing the support function.

[0239] While the folds 306 are depicted as being fully inflated in the expanded configuration illustrated in FIGS. 9A to 9C, residual folds may remain after inflation. Residual folds may be defined as folds which following inflation, still have some portion of the original fold remaining. Residual folds therefore still have a trough and a peak; however, the distance between the peak and trough may be reduced compared with the pre-inflation configuration of the fold. Additionally or alternatively, one or more folds, residual or otherwise, may be radially compressed after inflation upon contact with a surface such that one or more folds are no longer present.

[0240] In use, the expandable element 302 of the expansion apparatus 300 is at least partially inflated by fluid pressure. Expansion of the element 302 and/or apparatus 300 may inflate the inflatable component 358 and urge fingers 356 apart. The component 357, sleeve 360 or fingers 356 may contact an surface such as casing, tubing or piping of a wellbore, and provide a support function. In the illustrated expanded configuration, the expandable element 302 has a shape of a prolate spheroid in the expanded configuration.

[0241] The described expansion apparatus may be used in a variety of applications. For example, the expansion apparatus may be incorporated into a tool string 250 as illustrated in FIG. 10. The tool string 250 is positioned within a wellbore 252. The wellbore 252 may be lined with casing, tubing and/or piping, or may be an open hole wellbore. The tool string 250 may be configured to be permanently or temporarily positioned within the wellbore 252. The tool string 250 comprises a body 254 connected to mechanical slips 256, the expansion apparatus 300 and an end element 258. While the expansion apparatus 300 is illustrated in FIG. 10, any of the described expansion apparatus may be incorporated into the tool string 250.

[0242] The body 254 is generally cylindrical. The mechanical slips 256 are illustrated in the actuated position. The slips 356 are actuated by an applied axial setting force. The slips 356 may permanently or temporarily secure the tool string 250 in the wellbore 252. After actuation of the mechanical slips 256, the expansion apparatus 300 and/or element 302 may transition from the initial non-expanded configuration to the expanded configuration. The expansion apparatus 300 may provide a support function to minimise extrusion of the tool string 250. After expansion of the apparatus 300 and/or element 302, the mechanical slips 256 may return to a non-actuated position. The described tool string 250 may relate to a bridge plug apparatus. The tool string 250 may comprise additional elements such as valves, gauges, batteries, communication modules, cable, slicklines, e-lines, etc.

[0243] Turning now to FIGS. 11A and 11B, an expansion apparatus 400 is shown. The expansion apparatus 400 is similar to the described expansion apparatus 100 shown in FIGS. 1 to 4 and as such like elements are referred to with the same reference numerals, incremented by 300.

[0244] The expansion apparatus 400 is shown in the expanded configuration. As with the expansion apparatus 300 shown in FIGS. 10A to 10D, the folds 406 are fully inflated such that no or few residual folds are present, and the expandable element 402 has a shape of a prolate spheroid. As illustrated in FIG. 11B, the first and second flank angles 420 and 422, respectively, are not equal. The first flank angle 420 determined relative to the longitudinal axis D-D is less than the second flank angle 422. While this difference in flank angles is depicted in the expanded configuration, the skilled reader will appreciate that such a difference may similarly be present in the non-expanded configuration.

[0245] FIGS. 12A to 12C depict an expansion apparatus 500. The expansion apparatus 500 is similar to the described expansion apparatus 100 shown in FIGS. 1 to 4 and as such like elements are referred to with the same reference numerals, incremented by 400. The expansion apparatus 500 surrounds tubing 550. The tubing 550 passes through the space encloses by the wall structure of the expandable element 502. The expansion apparatus 500 is sized such that the wall structure surrounds the tubing 550. The tubing 500 is sealed within the expansion apparatus 500 by seals 570. The seals 560 are positioned on either longitudinal end of the expansion apparatus 500 to seal the tubing 550 relative to the expansion apparatus 500. The tubing 550 may take the form of a pipe, or bladder entirely or partially internal to the wall structure. As shown in FIG. 12C, an anchor 560 may surround the expansion apparatus 500. The anchor 560 function to anchor or secure the expansion apparatus to a surrounding surface.

[0246] The tubing 550 further comprises ports 580. The ports 580 are located within an wall of the tubing 550. The ports 580 are configured to allow for inflation of the expandable element 502. The ports 580 allow for fluid within the tubing 550 to flow into the expansion apparatus 500 and inflate the expansion apparatus 500. The ports 580 may be controlled to open to allow expansion by inflation of the wall structure. The ports 580 may be controlled via a communication signal. While multiple ports 580 have been illustrated, a single port 580 may be used.

[0247] FIGS. 13A to 13B shown an expansion apparatus 600. The expansion apparatus 600 is similar to the described expansion apparatus 100 shown in FIGS. 1 to 4 and as such like elements are referred to with the same reference numerals, incremented by 500. Slip 660 surround the third section 614 of the expandable element 602. The slip 660 are configured to anchor the expansion apparatus 600 to a surface, for example against the inner surface of a wellbore. The slips 660 is made of material suitable for securing the expansion apparatus to the surface. The slip 660 is configured to grip the expansion apparatus 600 without damaging the expansion apparatus. The slip 660 forms a near circle around the expansion apparatus 600. An exemplary slip 660 comprises three or more steel wedges that are hinged together, forming a near circle around the expansion apparatus 600. Expansion of the element 602 as illustrated in FIGS. 13A and 13B may assist in securing the expansion apparatus 600 to a surface via the slips 660.

[0248] In use, the described expansion apparatus may be located in a wellbore and then inflated to provide a seal. The described anchor 560 or slips 660 may assist with locating the expansion apparatus within a wellbore.

[0249] While particular folds 106 have been described and illustrated, one of skill in the art will appreciate that other configurations are possible. As shown in FIG. 14, folds 700 of the described expansion apparatus may have a canted profile.

[0250] The folds 700 generally have a radially tortuous or serpentine path. Each fold 106 comprise an arcuate section with sections extending from either end of the arcuate section. However, in the illustrated arrangement, the folds 700 have a profile that is deviated from a radial line extending from the expandable element.

[0251] The folds 106 define peaks 720 with a trough 722 between adjacent peaks 720. Each peak 720 and each trough 722 is generally rounded. Each peak 720 defines a pocket 724. The sidewalls of the wall structure of a peak 720 define the pocket 724.

[0252] In the illustrated arrangement, a sidewall of the peaks 720 and troughs 722 has a constant thickness. Furthermore, the sidewalls of the peaks 720 and troughs 722 are coplanar. One of skill in the art will appreciate, that this may be varied depending on the application and environment of use of the expansion apparatus.

[0253] Thus, in contrast with the arrangement illustrated in FIG. 2, each peak 720 is not centred about a radial line (indicated as LL in FIG. 14) of the expandable element 102. In the illustrated arrangement, each peak 720 is angled with respect to a radial line extending from the radial centre of the expandable element. In the illustrated arrangement, each peak 720 is angled in the clockwise direction, although one of skill in the art will appreciated each peak 720 may be angled in the counter clockwise direction instead. Accordingly, while each peak 720 defines a pocket 724, each pocket 720 has a similarly angled tear drop shape.

[0254] One or more of the pockets 724 may expand upon inflation of the expandable element 102. Altering the shape, dimension and configuration of one or more of the peaks 720, trough 724 and pockets 724 may alter the inflation profile of the expansion apparatus.

[0255] It should be understood that the examples provided are merely exemplary of the present disclosure, and that various modifications may be made thereto.