Volumetric Compensation for Sealing Performance Under Large Temperature Swing Conditions

This application is a divisional of U.S. patent application Ser. No. 18/095,413, filed Jan. 10, 2023, which is incorporated by reference herein in their entirety.

During some oilfield operations, such as water injection, downhole temperatures can drop substantially. This can have a negative impact on the performance of downhole rubber or polymeric seals, such as packer elements, bridge plugs, O-rings, and liner hangers. The main cause of this negative impact is that rubber and polymers typically have a much larger coefficient of thermal expansion (CTE) than metallic materials, such as steels. This can cause a seal, such as packer elements, which function well at nominal operating temperatures (and small variations from it); however, when the temperature drop from nominal temperatures is large, the seal may leak due to excessive shrinkage of the rubber/polymeric materials, thereby degrading the integrity of the seal.

The present disclosure relates to creating seals with materials or metamaterials that have a negative CTE (or exhibit negative CTE) to allow for volumetric compensation during large temperature swings (e.g., 200° F. to 300° F.). Examples include creating seals that include: a lattice of materials that have a normal positive CTE, a spring constructed of materials that have a negative CTE, and/or a shape memory alloy (SMA) that contracts during a phase change. The SMA has a negative CTE. The lattice exhibits negative CTE over a large temperature swing although made of positive CTE components.

In some examples, these materials/metamaterials are employed as fillers for a seal (internal compensation), thus maintaining the seal's effective overall volume during a temperature change. In other examples, the materials/metamaterials are employed as spacers (external compensation) between sealing components, backup shoes, springs, or compression retention devices. The external compensation can maintain seal performance during large temperature drop without changing the rubber components used for sealing.

The volume of the negative CTE materials (e.g., metals, plastics) will expand when the temperature drops, and can compensate volume loss due to shrinkage of the rubber/polymer (when the temperature drops) to maintain compression on the sealing elements and trapped rubber pressure. The sealing elements will shrink when the temperature rises to prevent seal element extrusion due to excessive element volume increase.

The negative CTE materials can substantially improve the robustness of the sealing component (e.g., O-ring, packer element) in downhole applications involving large temperature swings, such as during injection/production cycles. The negative CTE materials are integrated into existing components without adding additional components to the packer system or change in the current design layout.

illustrates a well system(operating environment) for a downhole tool, in accordance with examples of the present disclosure. In some examples, the downhole toolmay include a bridge plug, vee packing, a seal gland, and/or a packing seal. A derrickwith a rig flooris positioned on the earth's surface. A wellboreis positioned below the derrickand the rig floorand extends into a subterranean formation. The wellboremay be lined with casingthat is cemented in place with cement. Althoughdepicts the wellborehaving a casingbeing cemented into place with cement, the wellboremay include open hole portion. Moreover, the wellboremay be an open-hole wellbore. The well systemmay equally be employed in vertical and/or deviated wellbores.

A tool stringextends from the derrickand the rig floordownwardly into the wellbore. The tool stringmay be any mechanical connection to the surface, such as, for example, wireline, slickline, jointed pipe, or coiled tubing. As depicted, the tool stringsuspends the downhole toolfor placement into the wellboreat a desired location to perform a specific downhole operation. In some examples, the downhole toolmay be hydraulically pumped into the wellbore. In some examples, the downhole toolmay include any type of wellbore zonal isolation device including, but not limited to, a frac plug, a bridge plug, a packer, a wiper plug, or a cement plug.

illustrates an internal compensation sealing configuration that includes negative CTE fillers, in accordance with examples of the present disclosure. Each of the components of the toolmay extend along a circumference of the tool(e.g., tubular tool), however only a portion of the toolis shown disposed in the casing(or open hole). The toolmay include a first wedgeand a second wedge. Adjacent to each of the wedges, respectively, are a first back-up shoeand a second back-up shoe.

A sealing element(e.g., rubber/polymer) may be disposed between the back-up shoes. The toolalso includes a mandrelsuch that the sealing elementis confined by the back-up shoes, a portion of the casing, and a portion of the mandrel. Negative CTE material(e.g., fillers) may be disposed (e.g., embedded) within the sealing element. When temperature drops, rubber sealing components shrink, but the negative CTE materialgrows, and thus can maintain the compression force on the sealing element. These volume growths all help to compensate the shrinkage of sealing components, and thus maintain the pressure in sealing components, maintain its sealing performance during temperature swings. A similar approach can be applied to O-rings to maintain its low temperature performance by maintaining a squeeze on it via volume compensation from spacers with negative CTE.

illustrates an internal compensation sealing configuration that includes a negative CTE filler in a sealing element, in accordance with examples of the present disclosure. Each of the components of the toolmay extend along a circumference of the tool(e.g., tubular tool), however only a portion of the toolis shown disposed in the casing(or open hole). The toolmay include a sealing elementfor use in expandable liner hanger (ELH) applications. The negative CTE materialmay be disposed/embedded within the sealing element, as shown. The negative CTE materialmay be disposed in continuous or discrete patterns around the mandrel. The sealing elementmay be disposed between a first spikeand a second spikeof the toolwhich may include an ELH.

illustrates an internal compensation sealing configuration that includes spacers and a negative CTE filler in an O-ring, in accordance with examples of the present disclosure. Each of the components of the toolmay extend along a circumference of the tool(e.g., tubular tool), however only a portion of the toolis shown disposed in the casing(or open hole). The toolmay include the O-ringdisposed between a first spacer(e.g., metal spacer) and a second spacer, for use in expandable liner hanger (ELH) applications. The negative CTE materialmay be disposed/embedded within the O-ring, as shown. The negative CTE materialmay be disposed in continuous or discrete patterns around the mandrel.

illustrates an external compensation sealing configuration that includes a spring and a spacer, in accordance with examples of the present disclosure. This configuration may be employed in a packer or bridge plug design. Each of the components of the toolmay extend along a circumference of the tool(e.g., tubular tool), however only a portion of the toolis shown disposed in the casing(or open hole).

Sealing elementsmay be disposed between the first back-up shoeand the second back-up shoe. A metallic spacerwith a negative CTE is disposed between the sealing elements. The sealing elementsand the spacerare confined by the casingand the mandrel. The first wedgeis adjacent to the first back-up shoe, and the second wedgeis adjacent to a metallic member(spring or solid elastic sleeve) that has a negative CTE. The memberis disposed between the second back-up shoeand the second wedge. Each of the wedges are stationary (e.g., each locked in place with an internal slip). In some examples, the metallic spring may be constructed from a lattice of struts where each of the struts has a positive CTE.

illustrates an example of an external spring latticewith negative CTE. The latticeexhibited a CTE of −70×10° C. over a temperature ranging from 0° C. to 200° C. The latticemay include titanium segmentsand aluminum segments. The segments are connected via an interference fitand are fastened with a screw. The lattice exhibits negative CTE over a large temperature swing although made of positive CTE components.

illustrates an external compensation sealing configuration including spacers made of negative CTE materials, in accordance with examples of the present disclosure. Each of the components of the toolmay extend along a circumference of the tool(e.g., tubular tool), however only a portion of the toolis shown disposed in the casing(or open hole). The toolmay include the O-ringdisposed between the first spacerand the second spacer, for use in any downhole sealing requirements that need O-Rings, for example expandable liner hanger (ELH) applications. The spacers may be made of the negative CTE material.

Some examples use the SMA or other phase changing alloys to achieve volumetric compensation in sealing device during large temperature swing and thus maintaining a sealing device's performance during the temperature cycle. The phase transformation induced by the temperature change in SMA reverses the deformation known as the shape memory effect (SME). The effect can be one-way or two-way. The two-way shape memory effect allows the material to remember two shapes: one at the high temperature, and one at the low temperature. The material can be trained to increase the length at low temperature.

As an example, the beam spring ofcan be replaced with two-way shape-memory material to increase the length at low temperature and compensate for the volume loss due to shrinkage of the seal element. Or alternatively, the beam spring can be combined with a two-way shape-memory material bar to form a bias spring to increase the length when temperature drops.

illustrates an external compensation sealing configuration including an SMA member, in accordance with examples of the present disclosure. This configuration may be employed in a packer or bridge plug design. Each of the components of the toolmay extend along a circumference of the tool(e.g., tubular tool), however only a portion of the toolis shown disposed in the casing(or open hole).

Sealing elementsmay be disposed between the first back-up shoeand the second back-up shoe. A spaceris disposed between the sealing elements. The sealing elementsand the spacerare confined by the casingand the mandrel. The first wedgeis adjacent to the first back-up shoe, and the second wedgeis adjacent to SMA member(e.g., a spring or a solid elastic sleeve) that has a negative CTE and is a two-way SMA. The memberis disposed between the second back-up shoeand the second wedge. Each of the wedges are stationary (e.g., each locked in place with an internal slip).

Examples of the SMA include MnCoGe alloys which have volume increase during the temperature drop. The MnCoGe-based compounds undergo a giant negative thermal expansion during the martensitic structural transition from hexagonal to orthorhombic structure. In the region near room temperature, these compounds exhibit −119×10-6/° C. In one example, the MnCoGe alloy is mixed with a polymer binder to create a more stable material with negative CTE.

illustrates an original hot state of the SMA member. F is a force exerted on the sealing element of the tool. As illustrated, during the hot state, the memberis compressed/shortened.illustrates the cold state of the SMA member. F is the force exerted on the sealing element of the tool. During the cold state, the SMA memberis expanded/lengthened.

illustrates an external sealing configuration including a beam spring combined with an SMA bar, in accordance with examples of the present disclosure. This configuration may be employed in a packer or bridge plug design. Each of the components of the toolmay extend along a circumference of the tool(e.g., tubular tool), however only a portion of the toolis shown disposed in the casing(or open hole). Sealing elementsmay be disposed between the first back-up shoeand the second back-up shoe.

A spaceris disposed between the sealing elements. The sealing elementsand the spacerare confined by the casingand the mandreland the back-up shoes. The first wedgeis adjacent to the first back-up shoe, and the second wedgeis adjacent to a two-way shape-memory material bar(e.g., member, sleeve) to form a bias spring to increase the length when temperature drops. A conventional beam spring(e.g., positive CTE) can be combined with the SMA member (bar). The springis disposed between the second back-up shoeand the bar. Each of the wedges are stationary (e.g., each locked in place with an internal slip).

illustrates an original hot state of the bar. F is a force exerted on the sealing element of the tool. As illustrated, during the hot state, the baris compressed/shortened.illustrates the cold state of the bar. F is the force exerted on the sealing element of the tool. During the cold state, the baris expanded/lengthened.

Accordingly, the systems and methods of the present disclosure allow for increasing the squeeze within an elastomer as the seal is cooled. This additional squeeze can be provided with a negative CTE material within the elastomer or with a negative CTE spring providing a force onto the rubber. The systems and methods may include any of the various features disclosed herein, including one or more of the following statements.

Statement 1. A downhole tool comprising: a sealing element; and a member with a negative coefficient of thermal expansion (CTE), the member configured to expand the sealing element during a temperature drop, wherein the member is external to the sealing element.

Statement 2. The downhole tool of the statement 1, wherein the sealing element is disposed between back-up shoes.

Statement 3. The downhole tool of the statement 1 or the statement 2, wherein the member is adjacent to one back-up shoe.

Statement 4. The downhole tool of any one of the statements 1-3, further comprising a spacer that is adjacent to the sealing element.

Statement 5. The downhole tool of any one of the statements 1-4, further comprising a wedge adjacent to the member.

Statement 6. The downhole tool of any one of the statements 1-5, further comprising a slip adjacent to the wedge.

Statement 7. The downhole tool of any one of the statements 1-6, wherein the member extends between the wedge and the one back-up shoe.

Statement 8. The downhole tool of any one of the statements 1-7, wherein the member is external to the back-up shoes.

Statement 9. The downhole tool of any one of the statements 1-8, wherein the member includes a spring or a spacer.

Statement 10. The downhole tool of any one of the statements 1-9, wherein the member includes a shape memory alloy.

Statement 11. The downhole tool of any one of the statements 1-10, further comprising a spring adjacent to the member.

Statement 12. A downhole tool comprising a sealing element and a lattice structure including segments, each segment having a positive coefficient of thermal expansion (CTE), the lattice structure configured to expand the sealing element during a temperature drop.

Statement 13. The downhole tool of the statement 12, wherein the lattice structure is external to the sealing element.

Statement 14. The downhole tool of any one of the statements 12 or 13, wherein the sealing element is disposed between back-up shoes.

Statement 15. The downhole tool of any one of the statements 12-14, wherein the lattice structure is adjacent to one back-up shoe.

Statement 16. The downhole tool of any one of the statements 12-15, further comprising a spacer that is adjacent to the sealing element.

Statement 17. The downhole tool of any one of the statements 12-16, further comprising a wedge adjacent to the lattice structure.

Statement 18. A downhole tool comprising a sealing element; and a member including a shape memory alloy (SMA), the SMA configured to expand the sealing element during a temperature drop.

Statement 19. The downhole tool of the statement 18, wherein the SMA is external to the sealing element.

Statement 20. The downhole tool of any one of the statements 18 or 19, further comprising a spring adjacent to the SMA.

Statement 21. A downhole tool comprising: a sealing element; and a filler with a negative coefficient of thermal expansion (CTE), the filler disposed inside of the sealing element and configured to expand the sealing element during a temperature drop.

Statement 22. The downhole tool of the statement 21, wherein the sealing element is disposed between back-up shoes.

Statement 23. The downhole tool of the statement 21 or the statement 22, wherein the sealing element is disposed between spikes.

Statement 24. A downhole tool comprising an O-ring; and a filler with a negative coefficient of thermal expansion (CTE), the filler disposed inside of the O-ring and configured to expand the O-ring during a temperature drop.