DOWNHOLE EXPANDABLE ASSEMBLY AND DOWNHOLE SYSTEM

Abstract

 The present invention relates to a downhole expandable assembly for arrangement in a borehole in a well to prevent formation collapse of an unconsolidated sand formation. The downhole expandable assembly comprises a tubular metal part 7 for mounting as part of a well tubular structure 5, the tubular metal part 7 having a longitudinal extension and an expansion opening 6; an expandable metal sleeve 8 surrounding the tubular metal part 7 and having an inner face 9 facing the tubular metal part 7 and an outer face 10 facing a wall 11 of the borehole 3; a first end 12 and a second end 13 of the expandable metal sleeve 8 being connected with the tubular metal part 7; and an annular space 15 between the inner face 9 of the expandable metal sleeve 8 and the tubular metal part 7. The downhole expandable assembly further comprises an expandable screen 16 arranged on the outer face 10 of the expandable metal sleeve 8 so that the expandable screen 16 is forced outwards by the expandable metal sleeve 8 during expansion of the expandable metal sleeve 8 into a position where the expandable screen 16 at least partly abuts the unconsolidated sand formation.

Description

Field of the invention

[0001] The present invention relates to a downhole expandable assembly for arrangement in a borehole in a well to prevent formation collapse of an unconsolidated sand formation. Furthermore, the invention relates to a downhole system comprising a well tubular structure, a first and a second annular barrier and a downhole expandable assembly.

Background art

[0002] In unconsolidated sand formations, sand has a higher risk of loosening during oil or gas production than in consolidated formations. If sand loosens during production, there is a risk of the sand formation collapsing, causing sand to flow with the production flow. As the sand-filled fluid flows in through openings in the completion components, such as inflow valves, the openings are very quickly enlargened and the components quickly have no function as the components are worn.

[0003] In order to prevent such sand formation collapses, expandable screens are expanded by cones forced through the inside of the expandable screen, thereby forcing the screen radially outwards into abutment with the sand formation. However, the known expandable screens are known to collapse very quickly after being set and are thus unable to support the unconsolidated sand formation.

Summary of the invention

[0004] It is an object of the present invention to wholly or partly overcome the above disadvantages and drawbacks of the prior art. More specifically, it is an object to provide an improved expandable assembly capable of supporting unconsolidated sand formations during production without collapsing or contracting significantly after being set.

[0005] The above objects, together with numerous other objects, advantages and features, which will become evident from the below description, are accomplished by a solution in accordance with the present invention by a downhole expandable assembly for arrangement in a borehole in a well to prevent formation collapse of an unconsolidated sand formation, comprising:

• a tubular metal part for mounting as part of a well tubular structure, the tubular metal part having a longitudinal extension and an expansion opening,
• an expandable metal sleeve surrounding the tubular metal part and having an inner face facing the tubular metal part and an outer face facing a wall of the borehole, a first end and a second end of the expandable metal sleeve being connected with the tubular metal part, and
• an annular space between the inner face of the expandable metal sleeve and the tubular metal part,
  wherein the downhole expandable assembly further comprises an expandable screen arranged on the outer face of the expandable metal sleeve so that the expandable screen is forced outwards by the expandable metal sleeve during expansion of the expandable metal sleeve into a position where the expandable screen at least partly abuts the unconsolidated sand formation.

[0006] In an embodiment, the expandable screen may comprise a screen element made of wounded wires or slotted liners.

[0007] Furthermore, the expandable screen may comprise layers of wounded wires or slotted liners.

[0008] In addition, the expandable screen may comprise projecting elements configured to maintain a distance between the screen element and the expandable metal sleeve.

[0009] In one embodiment, the expandable metal sleeve may comprise projections and/or grooves configured to provide a flow along the outer face of the expandable metal sleeve.

[0010] In another embodiment, the ends of the expandable metal sleeve may be welded to the tubular part.

[0011] Also, the ends of the expandable metal sleeve may be connected to the tubular part by means of connection parts.

[0012] Additionally, the ends of the expandable metal sleeve may be crimped onto the tubular part.

[0013] The expandable screen may have a first end part connected to the tubular metal part.

[0014] Moreover, the expandable screen may have a second end part extending past the expandable metal sleeve along the longitudinal extension of the tubular metal part.

[0015] Also, the end parts of the expandable screen and the ends of the expandable metal sleeve may be connected to the tubular metal part by means of connection parts, the connection parts each having a connection element overlapping the expandable screen and the expandable metal sleeve.

[0016] The downhole expandable assembly may further comprise an inflow device arranged adjacent to the expandable metal sleeve

[0017] In an embodiment, the expandable screen may at least partly overlap the inflow device, providing fluid communication between the expandable screen and the inflow device.

[0018] Furthermore, the downhole expandable assembly may further comprise a shroud fluidly connected with the expandable screen.

[0019] Additionally, the shroud may overlap the inflow device.

[0020] Also, the inflow device may be in fluid communication with a production opening in the tubular structure.

[0021] Moreover, inflow devices may be arranged adjacent to the first and the second end of the expandable metal sleeve, respectively.

[0022] Further, the expansion opening may be arranged opposite the annular space.

[0023] In addition, a screen may be arranged opposite the expansion opening in the annular space.

[0024] In an embodiment, the expandable metal sleeve may have areas of metal material being permeable above a predetermined pressure.

[0025] Furthermore, the expandable metal sleeve may be designed to fracture at a predetermined pressure above the expansion pressure to provide an aperture in the expandable metal sleeve through which production fluid is allowed to flow.

[0026] Also, the expandable metal sleeve may comprise a shear disc providing an aperture in the expandable metal sleeve through which production fluid is allowed to flow.

[0027] The present invention furthermore relates to a downhole system comprising:

• a well tubular structure arranged in a borehole in an unconsolidated sand formation,
• a first and a second annular barrier, each annular barrier comprising:
  • a tubular metal barrier part for mounting as part of the well tubular structure,
  • an expandable barrier metal sleeve surrounding the tubular metal barrier part and having an inner barrier face facing the tubular metal barrier part and an outer barrier face facing a wall of the borehole, each end of the expandable metal barrier sleeve being connected with the tubular metal barrier part, and
  • an annular barrier space between the inner barrier face of the expandable metal barrier sleeve and the tubular metal barrier part,

the annular barriers isolating a first production zone when expanded, and

• a downhole expandable assembly according to any of the preceding claims, the downhole expandable assembly being arranged in the first production zone between the first and second annular barriers.

[0028] The downhole system may further comprise a well data monitoring device.

[0029] In an embodiment, the well data monitoring device may comprise at least one sensor, a storing unit, a communication module and/or a power supply.

[0030] In another embodiment, the downhole system may further comprise a plurality of downhole expandable assemblies arranged in the first production zone.

[0031] In yet another embodiment, the downhole system may further comprise a third annular barrier providing a second production zone.

[0032] Finally, the downhole system may further comprise a plurality of downhole expandable assemblies arranged in the second production zone.

Brief description of the drawings

[0033] The invention and its many advantages will be described in more detail below with reference to the accompanying schematic drawings, which for the purpose of illustration show some non-limiting embodiments and in which

Fig. 1 shows a cross-sectional view of a downhole expandable assembly along the longitudinal extension of the assembly,

Fig. 2 shows a cross-sectional view of a downhole expandable assembly perpendicular to the longitudinal extension of the assembly, the downhole expandable assembly having projecting elements between the screen and the tubular metal part,

Fig. 3 shows a cross-sectional view of a downhole expandable assembly perpendicular to the longitudinal extension of the assembly where the expandable metal sleeve has projecting elements,

Fig. 4 shows a cross-sectional view of another downhole expandable assembly,

Fig. 5 shows a cross-sectional view of yet another downhole expandable assembly,

Fig. 6 shows a cross-sectional view of a downhole system,

Fig. 7 shows a cross-sectional view of another downhole expandable assembly,

Fig. 8 shows a cross-sectional view of yet another downhole system,

Fig. 9 shows a cross-sectional view of an expandable metal sleeve,

Fig. 10 shows a cross-sectional view of another downhole expandable assembly,

Fig. 11A shows a cross-sectional view of part of a downhole expandable assembly during expansion, and

Fig. 11B shows the downhole expandable assembly of Fig. 11A after expansion.

[0034] All the figures are highly schematic and not necessarily to scale, and they show only those parts which are necessary in order to elucidate the invention, other parts being omitted or merely suggested.

Detailed description of the invention

[0035] Fig. 1 shows a downhole expandable assembly 1 arranged in a borehole 2 in a well 3 to prevent formation collapse of an unconsolidated sand formation 4. The downhole expandable assembly 1 comprises a tubular metal part 7 mounted as part of a well tubular structure 5. The tubular metal part 7 has a longitudinal extension and an expansion opening 6. The downhole expandable assembly 1 further comprises an expandable metal sleeve 8 surrounding the tubular metal part 7 and having an inner face 9 facing the tubular metal part and an outer face 10 facing a wall 11 of the borehole 2. A first end 12 and a second end 13 of the expandable metal sleeve are connected with the tubular metal part 7, thereby defining an annular space 15 between the inner face of the expandable metal sleeve 8 and the tubular metal part. The downhole expandable assembly 1 further comprises an expandable screen 16 arranged on the outer face 10 of the expandable metal sleeve 8 so that the expandable screen 16 is forced radially outwards by the expandable metal sleeve during expansion of the expandable metal sleeve into a position where the expandable screen at least partly abuts the unconsolidated sand formation, as shown in Fig. 1.

[0036] The downhole expandable assembly 1 is expanded by pressurised fluid entering the expansion opening 6, causing the expandable screen to expand to abut and support the sand formation and thus prevent the sand from loosening from the formation. The tubular metal part 7 is pressurised either from surface or by means of a tool isolating a zone inside the tubular metal part 7 opposite the opening. By pressurising the expandable metal sleeve 8, the expandable screen 16 is expanded evenly along the circumference of the expandable screen while still being able to conform to the borehole 2. In prior art solutions, the cone expands the screen equally and thus also widens the borehole in the areas where the borehole is not perfectly round, creating a risk of destroying the cohesion of the sand formation and initiating the unconsolidation of the formation.

[0037] The ends of the expandable metal sleeve 8 are welded to the tubular part 7 by means of weldings 23. The expandable screen 16 is also welded to the tubular part, as shown in Fig. 1.

[0038] The expandable screen 16 comprises a screen element 17 made of wounded wires or slotted liners. The expandable screen 16 comprises layers of wounded wires or slotted liners, allowing fluid from the formation to flow into the expandable screen and along the screen up and down the layers and thus along the longitudinal extension of the expandable screen.

[0039] In Fig. 2, the expandable screen 16 comprises projecting elements 19 configured to maintain a distance D between the screen element 17 and the expandable metal sleeve 8, thereby creating flow channels 27 or one annular channel 27 underneath the screen. The projecting elements 19 are elongated elements or dot-shaped elements. When the expandable screen 16 has such projecting elements 19, the screen element 17 only has one slotted liner or one wounded layer as the fluid is able to flow along the longitudinal extension in the flow channel/-s 27.

[0040] In Fig. 3, the expandable metal sleeve 8 comprises projections 21 and grooves 22 enabling fluid from the formation to flow along the outer face 10 of the expandable metal sleeve 8 in flow channels 27. In this way, fluid flowing through the expandable screen 16 can flow along the grooves 22 and out on either side of the downhole expandable assembly 1 and into the well tubular structure through a production opening 26 in the well tubular structure at a distance from the downhole expandable assembly 1, as shown in Fig. 6.

[0041] The ends 12, 13 of the expandable metal sleeve 8 may be connected to the tubular part 7 by means of connection parts 24 having connection elements 29 overlapping the expandable screen 16 and the expandable metal sleeve 8, as shown in Fig. 4. The ends of the expandable metal sleeve 8 may be crimped onto the tubular part 7 so that both the expandable screen 16 and the expandable metal sleeve 8 are connected to the tubular metal part 7 in connection parts 24, as shown in Fig. 4, or by welded connections, as shown in Fig. 5.

[0042] In Fig. 5, the expandable screen 16 has a first end part 24 which is welded to the tubular part 7 together with the first end 12 of the expandable metal sleeve 8, and the expandable screen 16 has a second end part 25 extending past the second end 13 of the expandable metal sleeve 8 along the longitudinal extension of the tubular metal part 7. The expandable screen 16 thus extends past an inflow device 28, such as a well inflow valve, controlling the inflow of production fluid. The second end part 25 extending past the second end 13 of the expandable metal sleeve 8 is welded to the inflow device 28, and an annular channel is defined between the expandable screen 16 and the inflow device 28 to collect production fluid flowing in through the screen along the entire circumference and lead the fluid to one or two production openings 26 in the tubular structure 5. As can be seen, the inflow device 28 is arranged adjacent to the expandable metal sleeve 8. In another embodiment, the expandable screen 16 only partly overlaps the inflow device 28, just enough to direct the fluid into the inflow device 28.

[0043] In Fig. 6, a downhole system 100 comprising the well tubular structure 5, annular barriers 30 and the downhole expandable assembly 1 is shown. The well tubular structure 5 is arranged in the borehole 2 in an unconsolidated sand formation 4, and a first and a second annular barrier 30 are expanded to isolate a production zone 101. Each annular barrier 30 comprises a tubular metal barrier part 7a mounted as part of the well tubular structure 5 as well as an expandable barrier metal sleeve 8a surrounding the tubular metal barrier part 7a and having an inner barrier face 31 facing the tubular metal barrier part and an outer barrier face 32 facing the wall 11 of the borehole. Each end of the expandable metal barrier sleeve 8a is connected with the tubular metal barrier part 7a, defining an annular barrier space 33 between the inner barrier face of the expandable metal barrier sleeve and the tubular metal barrier part. The downhole expandable assembly 1 is arranged in the first production zone 101 between the first and second annular barriers 30. One inflow device 28 is arranged adjacent to the first end 12 of the expandable metal sleeve and a second inflow device 28 is arranged adjacent to the second end 13 of the expandable metal sleeve. The annular barriers are expanded by pressurised fluid in the tubular metal barrier part 7a flowing in through an expansion opening 6a in the tubular metal barrier part 7a and into the annular space opposite the expansion opening 6a. The expandable assembly 1 supports most of the sand formation in the production zone 101, and the production fluid from the formation can flow into either one of the inflow devices 28. The downhole system 100 further comprises a well data monitoring device 34 for monitoring the condition of the well and the well fluid/production fluid. The well data monitoring device 34 has sensors for measuring pressure, temperature, flow content etc. The well data monitoring device 34 comprises a storing unit and a communication module for communicating the well data to surface, e.g. by means of a tool arranged opposite the well data monitoring device 34 or through a communication system in the well. The well data monitoring device 34 may further comprise a power supply, such as a rechargeable battery.

[0044] As shown in Fig. 7, the downhole expandable assembly 1 further comprises a shroud 35 connected with the expandable screen 16 and overlapping the inflow device 28, thereby creating a fluid channel 38 between the shroud 35 and the inflow device 28 for collecting fluid and directing the fluid into the inflow device 28 and out though the production opening 26. The inflow device 28 may also be arranged in the production opening 26 in the tubular structure.

[0045] The downhole system 100 may, instead of one long downhole expandable assembly 1, comprise a plurality of downhole expandable assemblies 1 arranged in the first production zone 101, as shown in Fig. 8. Inflow devices 28 are arranged between the downhole expandable assemblies 1 opposite production openings 6 in the tubular structure 5. The first production zone 101 is defined as between the two annular barriers. The downhole system 100 may in another embodiment comprise a third annular barrier arranged next two one of the annular barriers, thereby providing a second production zone (not shown), and second downhole expandable assemblies 1 may be arranged in a similar manner in the second zone and so forth.

[0046] Fig. 9 shows the expandable metal sleeve 8 having areas of metal material being permeable, e.g. above a predetermined pressure. During expansion, the expansion pressure is so high that even though some fluid may leak through these areas, the expansion still occurs. The areas may be made of a metal material which is impermeable up to a predetermined pressure, and above that pressure, the material of the areas becomes permeable, also when the pressure subsequently decreases again. In another embodiment, the areas are shear discs bursting at a predetermined pressure.

[0047] As shown in Fig. 10, the expandable metal sleeve 8 may also be designed to fracture at a predetermined pressure above the expansion pressure to provide an aperture 44 in the expandable metal sleeve through which production fluid is allowed to flow. A screen 45 is arranged opposite the expansion opening 6 in the annular space 15 so that the production fluid or well fluid is slowed downhole when entering the expansion opening or so that the fluid is further filtered. In another embodiment, the expandable metal sleeve comprises a shear disc providing the aperture in the expandable metal sleeve through which production fluid is allowed to flow. The shear disc may also be provided in a connection part or in one of the ends of the expandable metal sleeve.

[0048] In Fig. 11A, pressurised fluid is expanding the expandable metal sleeve 8, and the first end 12 is then pressed to abut the connection part 24 so that fluid is prevented from circumferenting the first end 12. In Fig. 12B, the expansion has ended and the pressure in the annular space 15 has decreased, and the first end 12 of the expandable metal sleeve 8 is thus no longer forced against the connection part 24. Then, fluid is allowed to flow past the first end 12 or flow through an opening 46 in the first end.

[0049] In order to expand the expandable metal sleeve of the expandable assembly or the annular barriers, the system may further comprise an isolation tool arranged opposite the expansion opening for isolating a zone opposite the opening and thus expanding the sleeve by pressurised fluid.

[0050] By fluid or well fluid is meant any kind of fluid that may be present in oil or gas wells downhole, such as natural gas, oil, oil mud, crude oil, water, etc. By gas is meant any kind of gas composition present in a well, completion, or open hole, and by oil is meant any kind of oil composition, such as crude oil, an oil-containing fluid, etc. Gas, oil, and water fluids may thus all comprise other elements or substances than gas, oil, and/or water, respectively.

[0051] By a casing or well tubular structure is meant any kind of pipe, tubing, tubular, liner, string etc. used downhole in relation to oil or natural gas production.

[0052] In the event that the tool is not submergible all the way into the casing, a downhole tractor can be used to push the tool all the way into position in the well. The downhole tractor may have projectable arms having wheels, wherein the wheels contact the inner surface of the casing for propelling the tractor and the tool forward in the casing. A downhole tractor is any kind of driving tool capable of pushing or pulling tools in a well downhole, such as a Well Tractor®.

[0053] Although the invention has been described in the above in connection with preferred embodiments of the invention, it will be evident for a person skilled in the art that several modifications are conceivable without departing from the invention as defined by the following claims.

Claims

1. A downhole expandable assembly (1) for arrangement in a borehole (2) in a well (3) to prevent formation collapse of an unconsolidated sand formation (4), comprising:

- a tubular metal part (7) for mounting as part of a well tubular structure (5), the tubular metal part having a longitudinal extension and an expansion opening (6),

- an expandable metal sleeve (8) surrounding the tubular metal part and having an inner face (9) facing the tubular metal part and an outer face (10) facing a wall (11) of the borehole, a first end (12) and a second end of the expandable metal sleeve being connected with the tubular metal part, and

- an annular space (15) between the inner face of the expandable metal sleeve and the tubular metal part,
wherein the downhole expandable assembly further comprises an expandable screen (16) arranged on the outer face of the expandable metal sleeve so that the expandable screen is forced outwards by the expandable metal sleeve during expansion of the expandable metal sleeve into a position where the expandable screen at least partly abuts the unconsolidated sand formation.

2. A downhole expandable assembly according to claim 1, wherein the expandable screen comprises a screen element (17) made of wounded wires or slotted liners.

3. A downhole expandable assembly according to claim 1 or 2, wherein the expandable screen comprises layers of wounded wires or slotted liners.

4. A downhole expandable assembly according to any of the preceding claims, wherein the expandable screen comprises projecting elements (19) configured to maintain a distance between the screen element and the expandable metal sleeve.

5. A downhole expandable assembly according to any of the preceding claims, wherein the expandable metal sleeve comprises projections (21) and/or grooves (22) configured to provide a flow along the outer face of the expandable metal sleeve.

6. A downhole expandable assembly according to any of the preceding claims, wherein the expandable screen has a first end part connected to the tubular metal part.

7. A downhole expandable assembly according to any of the preceding claims, wherein the expandable screen has a second end part (25) extending past the expandable metal sleeve along the longitudinal extension of the tubular metal part.

8. A downhole expandable assembly according to any of the preceding claims, further comprising an inflow device (28) arranged adjacent to the expandable metal sleeve

9. A downhole expandable assembly according to any of the preceding claims, wherein the expandable screen at least partly overlaps the inflow device, providing fluid communication between the expandable screen and the inflow device.

10. A downhole expandable assembly according to any of the preceding claims, further comprising a shroud (35) fluidly connected with the expandable screen.

11. A downhole expandable assembly according to any of the preceding claims, wherein the expandable metal sleeve has areas of metal material being permeable above a predetermined pressure.

12. A downhole expandable assembly according to any of the preceding claims, wherein the expandable metal sleeve is designed to fracture at a predetermined pressure above the expansion pressure to provide an aperture (44) in the expandable metal sleeve through which production fluid is allowed to flow.

13. A downhole system (100) comprising:

- a well tubular structure arranged in a borehole (2) in an unconsolidated sand formation (4),

- a first and a second annular barrier (30), each annular barrier comprising:

- a tubular metal barrier part (7a) for mounting as part of the well tubular structure,

- an expandable barrier metal sleeve (8a) surrounding the tubular metal barrier part and having an inner barrier face (31) facing the tubular metal barrier part and an outer barrier face (32) facing a wall (11) of the borehole, each end of the expandable metal barrier sleeve being connected with the tubular metal barrier part, and

- an annular barrier space (33) between the inner barrier face of the expandable metal barrier sleeve and the tubular metal barrier part,

the annular barriers isolating a first production zone (101) when expanded, and

- a downhole expandable assembly (1) according to any of the preceding claims, the downhole expandable assembly being arranged in the first production zone between the first and second annular barriers.

14. A downhole system according to claim 13, further comprising a well data monitoring device (34).

15. A downhole system according to claim 13, further comprising a plurality of downhole expandable assemblies arranged in the first production zone.

Drawing