Patent Application
20240229594
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.
These drawings illustrate certain aspects of some examples of the present disclosure and should not be used to limit or define the disclosure.
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.
A tool string 118 extends from the derrick 112 and the rig floor 114 downwardly into the wellbore 120. The tool string 118 may be any mechanical connection to the surface, such as, for example, wireline, slickline, jointed pipe, or coiled tubing. As depicted, the tool string 118 suspends the downhole tool 100 for placement into the wellbore 120 at a desired location to perform a specific downhole operation. In some examples, the downhole tool 100 may be hydraulically pumped into the wellbore 120. In some examples, the downhole tool 100 may 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.
A sealing element 208 (e.g., rubber/polymer) may be disposed between the back-up shoes. The tool 100 also includes a mandrel 210 such that the sealing element 208 is confined by the back-up shoes, a portion of the casing 125, and a portion of the mandrel 210. Negative CTE material 212 (e.g., fillers) may be disposed (e.g., embedded) within the sealing element 208. When temperature drops, rubber sealing components shrink, but the negative CTE material 212 grows, and thus can maintain the compression force on the sealing element 208. 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.
Sealing elements 208 may be disposed between the first back-up shoe 204 and the second back-up shoe 206. A metallic spacer 300 with a negative CTE is disposed between the sealing elements 208. The sealing elements 208 and the spacer 300 are confined by the casing 125 and the mandrel 210. The first wedge 200 is adjacent to the first back-up shoe 204, and the second wedge 202 is adjacent to a metallic member 302 (spring or solid elastic sleeve) that has a negative CTE. The member 302 is disposed between the second back-up shoe 206 and the second wedge. Each of the wedges are stationary (e.g., each locked in place with an internal slip 304). In some examples, the metallic spring may be constructed from a lattice of struts where each of the struts has a positive CTE.
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 of
Sealing elements 208 may be disposed between the first back-up shoe 204 and the second back-up shoe 206. A spacer 600 is disposed between the sealing elements 208. The sealing elements 208 and the spacer 600 are confined by the casing 125 and the mandrel 210. The first wedge 200 is adjacent to the first back-up shoe 204, and the second wedge 202 is adjacent to SMA member 602 (e.g., a spring or a solid elastic sleeve) that has a negative CTE and is a two-way SMA. The member 602 is disposed between the second back-up shoe 206 and the second wedge. Each of the wedges are stationary (e.g., each locked in place with an internal slip 304).
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.
A spacer 600 is disposed between the sealing elements 208. The sealing elements 208 and the spacer 600 are confined by the casing 125 and the mandrel 210 and the back-up shoes. The first wedge 200 is adjacent to the first back-up shoe 204, and the second wedge 202 is adjacent to a two-way shape-memory material bar 700 (e.g., member, sleeve) to form a bias spring to increase the length when temperature drops. A conventional beam spring 702 (e.g., positive CTE) can be combined with the SMA member (bar 700). The spring 702 is disposed between the second back-up shoe 206 and the bar 700. Each of the wedges are stationary (e.g., each locked in place with an internal slip 304).
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.
Statement 25. The downhole tool of the statement 24, wherein the O-ring is disposed between spacers.
Although the present disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions, and alterations may be made herein without departing from the spirit and scope of the disclosure as defined by the appended claims. The preceding description provides various examples of the systems and methods of use disclosed herein which may contain different method steps and alternative combinations of components. It should be understood that, although individual examples may be discussed herein, the present disclosure covers all combinations of the disclosed examples, including, without limitation, the different component combinations, method step combinations, and properties of the system. It should be understood that the compositions and methods are described in terms of “comprising,” “containing,” or “including” various components or steps, the compositions and methods can also “consist essentially of” or “consist of” the various components and steps. Moreover, the indefinite articles “a” or “an,” as used in the claims, are defined herein to mean one or more than one of the elements that it introduces.
For the sake of brevity, only certain ranges are explicitly disclosed herein. However, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as ranges from any lower limit may be combined with any other lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited. Additionally, whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range are specifically disclosed. In particular, every range of values (of the form, “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a-b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values even if not explicitly recited. Thus, every point or individual value may serve as its own lower or upper limit combined with any other point or individual value or any other lower or upper limit, to recite a range not explicitly recited.
Therefore, the present examples are well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular examples disclosed above are illustrative only and may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Although individual examples are discussed, the disclosure covers all combinations of all of the examples. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. It is therefore evident that the particular illustrative examples disclosed above may be altered or modified and all such variations are considered within the scope and spirit of those examples. If there is any conflict in the usages of a word or term in this specification and one or more patent(s) or other documents that may be incorporated herein by reference, the definitions that are consistent with this specification should be adopted.
