Connection Members Including Shape Memory Materials, Downhole Tools Including the Connection Members, and Methods of Forming the Downhole Tools

This application is a continuation of U.S. patent application Ser. No. 18/459,069, filed Aug. 31, 2023, which claims the benefit under 35 U.S.C. § 119 (e) of U.S. Provisional Patent Application Ser. No. 63/374,190, filed Aug. 31, 2022, the disclosure of each of which is hereby incorporated herein in its entirety by this reference.

Embodiments of the present disclosure generally relate to shape memory materials. In particular, embodiments of the present disclosure relate to connection members including shape memory material, downhole tools including the connection members, and methods of forming the downhole tools.

Wellbores are formed in subterranean formations for various purposes including, for example, extraction of oil and gas from the subterranean formation and extraction of geothermal heat from the subterranean formation. Wellbores may be formed in a subterranean formation using one or more earth-boring tool(s), such as an earth-boring rotary drill bit, secured to a series of elongated tubular segments connected end-to-end in what is referred to in the art as a “drill string.” During drilling operations, the drill string extends from an uphole end at a surface of a drilling rig down to the earth-boring tool (e.g., the drill bit) at the downhole end of the drill string. The earth-boring rotary drill bit is rotated and advanced into the subterranean formation. As the earth-boring rotary drill bit rotates, the cutting elements, cutters, or abrasive structures thereof cut, crush, shear, and/or abrade away the formation material to form the wellbore. As formation material is removed from the wellbore, the wellbore elongates. Additional tubular segments may be sequentially added to the uphole end of the drill string to maintain contact of the earth-boring tool with the bottom of the wellbore.

A downhole end of the drill string at the bottom of the wellbore being drilled generally includes an assembly of tools and components often referred to in the art as a “bottom-hole assembly” (BHA). The BHA generally includes one or more downhole tools to detect information about the drilling process, evaluate the formation being drilled, and relay that information to the surface in real-time. The downhole tool(s) may be positioned within the interior of and secured to a tubular element of the drill string, such as a drill collar. For example, a downhole tool may be positioned within a subassembly or a drill collar that may be coupled to additional tubular segments of the drill string, such as additional drill collars, subassemblies, drill pipe, downhole motors, etc.

During drilling operations, drilling fluid is pumped from the drilling rig down through the center of the drill string, often through a downhole motor, out from nozzles of the drill bit, and circulates through the wellbore back to the drilling rig. Since downhole tools are often positioned within the drill string and come in direct contact with the drilling fluid circulating through the drill string, downhole tools may be made of materials that are resistant to abrasion and corrosion.

Embodiments described herein include shape memory material structures, downhole tools including shape memory materials, and methods of forming downhole tools that include shape memory materials.

In one illustrative embodiment, the present disclosure provides a connection member including a body including a shape memory material configured to transition from a first state having a first configuration to a second state having a second configuration in response to application of a stimulus. The body includes one or more sidewalls and a connection feature. The one or more sidewalls define an opening extending between ends thereof. The connection feature is on at least a portion of the one or more sidewalls. The connection feature includes the shape memory material and is configured to couple the body to a component while in the first state.

In another illustrative embodiment, the present disclosure provides a downhole valve system for use in a borehole. The downhole valve system includes a first downhole component, a second downhole component, and a connection member. The first downhole component made from a brittle material includes a longitudinal axis. The second downhole component includes a first connection feature. The connection member formed from a shape memory material and includes: an outer surface including an outer diameter; an inner surface including an inner diameter, one of the outer diameter and the inner diameter modifiable by applying a stimulus to the shape memory material; and a second connection feature, complimentary of the first connection feature, formed on one of the outer surface and the inner surface. The connection member secured to the first downhole component at a corresponding surface of the one of the inner diameter and the outer diameter and to the second downhole component via the first connection feature and the second connection feature to connect the second downhole component to the first downhole component.

In a further illustrative embodiment, the present disclosure provides a downhole valve system for use in a borehole. The downhole valve system includes a first downhole component, a second downhole component, and a connection member. The first downhole component made from a brittle material includes a longitudinal axis. The connection member formed from a shape memory material and includes: an outer surface including an outer diameter and an inner surface including an inner diameter. One of the outer diameter and the inner diameter modifiable by applying a stimulus to the shape memory material. The connection member secured to the first downhole component at a first corresponding surface of the one of the inner diameter and the outer diameter, and the connection member secured to the second downhole component at a second corresponding surface of the one of the inner diameter and the outer diameter to connect the second downhole component to the first downhole component.

In yet another illustrative embodiment, the present disclosure provides a method of forming a downhole tool. The method includes providing a first downhole component made from a brittle material and including a longitudinal axis and a second downhole component including a first connection feature. The method also includes connecting the second downhole component to the first downhole component with a connection member formed from a shape memory material. The connection member including: an outer surface including an outer diameter; an inner surface including an inner diameter, one of the inner diameter and the outer diameter modifiable by applying a stimulus to the shape memory material; and a second connection feature, complimentary of the first connection feature, formed on one of the outer surface and the inner surface, the connection formed by securing the connection member to the first downhole component at a corresponding surface of the one of the inner diameter and the outer diameter and connecting the connection member to the second downhole component via the first connection feature and the second connection feature to connect the second downhole component to the first downhole component.

Certain structures, such as components of downhole tools, may be made of materials that are generally durable in terms of high hardness, resistant to erosion, corrosion, and abrasion, and also lightweight due to a relatively low density. Materials exhibiting desirable properties for certain downhole tool applications may also be relatively brittle and include materials such as ceramics or hard metal. While the chemical and thermal resistance of brittle materials, such as ceramics, makes them attractive materials for many applications, brittle materials are generally difficult to machine in comparison to metals. In addition, it may be desirable to connect brittle structures to one or more additional structures to form an assembly. For example, downhole tools generally include a variety of components that are connected together before being positioned within the drill string. Thus, the difficulty to machine brittle materials presents challenges for connecting brittle structures to other structures of an assembly. For example, it is difficult manufacture a thread in a brittle material. Even though it may be possible to manufacture a thread in a hard metal, this thread would not provide a reliable mechanical connection due to the missing elastic material properties of the hard metal, required in a threaded connection. To address this issue, metallic connection members, such as sleeves, or threaded sleeves, can be machined to size and then press-fit onto the ceramic material by first heating the metallic sleeve for thermal expansion. However, structures designed for a press-fit or interference fit require precision machining and procedures that are prone to error.

Thus, in accordance with embodiments of this disclosure, connection members may include a shape memory material configured to transition from a first state having a first configuration to a second state having a second configuration, and vice versa, in response to application of a stimulus, such as a temperature, stress (optical stress, magnetic stress, or mechanical stress), or electrical current. The connection members may exhibit super-elastic properties, which may facilitate connections between brittle structures (e.g., ceramic, hard metal, glass, graphite, etc.) without press-fit or gluing procedures. For example, the shape memory material of the connection member may be in a second state below a transition temperature, and an opening within the connection member may be enlarged such that the connection member can be positioned on a brittle structure. Once positioned in a desired location, the connection member may be exposed to a temperature above the transition temperature. Exposing the connection members to a temperature above the transition temperature initiates a state change from the second state back to the first state, and results in a change in volume and configuration (e.g., shape, such as shrinking or expending) to secure the connection member to the brittle structure. The connection member may then be machined to form a connection feature (e.g., threads) that can be used to secure the brittle structure to another structure of the downhole tool. In certain embodiments, the connection member may be machined to form the connection feature before securing the connection member to the brittle structure. In other embodiments, instead of exposing the connection member to a temperature above the transition temperature, a stress or an electrical current may be used to initiate the change from the second state back to the first state.

The following description provides specific details, such as specific shapes, specific sizes, dimensions, specific material compositions, and specific processing conditions, in order to provide a thorough description of embodiments of the present disclosure. However, a person of ordinary skill in the art will understand that the embodiments of the disclosure may be practiced without necessarily employing these specific details. Embodiments of the disclosure may be practiced in conjunction with conventional fabrication techniques employed in the industry. In addition, the description provided below does not form a complete process flow for manufacturing a connection member or a downhole tool. Only those process acts and structures necessary to understand the embodiments of the disclosure are described in detail below. Additional acts to form a complete connection member or a complete downhole tool from the structures described herein may be performed by conventional fabrication processes and additive manufacturing processes.

Drawings presented herein are for illustrative purposes only, and are not meant to be actual views of any particular material, component, structure, device, or system. Variations from the shapes depicted in the drawings as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments described herein are not to be construed as being limited to the particular shapes or regions as illustrated, but include deviations in shapes that result, for example, from manufacturing. For example, a region illustrated or described as box-shaped may have rough and/or nonlinear features, and a region illustrated or described as round may include some rough and/or linear features. Moreover, sharp angles that are illustrated may be rounded, and vice versa. Thus, the regions illustrated in the figures are schematic in nature, and their shapes are not intended to illustrate the precise shape of a region and do not limit the scope of the present claims. The drawings are not necessarily to scale. Additionally, elements common between figures may retain the same numerical designation.

As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

As used herein, the term “substantially” in reference to a given parameter, property, or condition means and includes to a degree that one of ordinary skill in the art would understand that the given parameter, property, or condition is met with a degree of variance, such as within acceptable tolerances. By way of example, depending on the particular parameter, property, or condition that is substantially met, the parameter, property, or condition may be at least 90.0 percent met, at least 95.0 percent met, at least 99.0 percent met, at least 99.9 percent met, or even 100.0 percent met.

As used herein, the term “about,” when used in reference to a numerical value for a particular parameter, is inclusive of the numerical value and a degree of variance from the numerical value that one of ordinary skill in the art would understand is within acceptable tolerances for the particular parameter. For example, “about,” in reference to a numerical value, may include additional numerical values within a range of from 90.0 percent to 110.0 percent of the numerical value, such as within a range of from 95.0 percent to 105.0 percent of the numerical value, within a range of from 97.5 percent to 102.5 percent of the numerical value, within a range of from 99.0 percent to 101.0 percent of the numerical value, within a range of from 99.5 percent to 100.5 percent of the numerical value, or within a range of from 99.9 percent to 100.1 percent of the numerical value.

As used herein, the term “shape memory material” includes any suitable shape memory material, including shape memory metal alloys and shape memory polymers. Shape memory metal alloys may include Ni-based alloys, Cu-based alloys, Co-based alloys, Fe-based alloys, Ti-based alloys, Al-based alloys, or any mixture thereof. Shape memory metal alloys may additionally include additional elements, such as Niobium (Nb), which may enhance the shape memory capability of such materials. For example, a shape memory metal alloy may include a 50:50 mixture by weight of nickel and titanium, a 55:45 mixture by weight of nickel and titanium, or a 60:40 mixture by weight of nickel and titanium. Many other compositions are possible and can be selected based on tool requirements and material properties as known in the art. Shape memory polymers may include, for example, epoxy polymers, thermoset polymers, thermoplastic polymers, or combinations or mixtures thereof. Other polymers that exhibit shape memory behavior may also be employed. Shape memory materials are polymorphic and may exhibit two or more crystal structures or states (e.g., phases). Shape memory materials may further exhibit a shape memory effect associated with the state (e.g., phase) transition between two crystal structures or states (e.g., phases), such as austenite and martensite. The austenitic phase exists at elevated temperatures, while the martensitic phase exists at low temperatures. The shape memory effect may be triggered by a stimulus that may be thermal, electrical, magnetic, or chemical, and which causes a transition from one solid state to another.

As used herein, the terms “brittle structure” and “brittle material” refer to materials that have low ductility and, at 20° C., undergo 5% or less elongation (i.e., tensile plastic deformation) before fracturing when tested in accordance with ASTM Test Method under ASTM E399 using a tensile testing machine. The definition of a brittle material as used in this application refers to material that possess a fracture toughness or crack resistance Klower than 20 MPa·m. As specific non-limiting examples, “brittle structures” and “brittle materials” include ceramics, glasses, graphite, certain metals (hard metals) and alloys, certain polymers, polycrystalline diamonds, etc. Ceramics may be Silicone Nitrides, Silicone Carbides, Aluminum Oxides, Zirconium Oxid or alternative technical ceramics. Hard metals may be Tungsten Carbide, Titanium Carbide, Titanium Nitride, or Tantalum Carbide.

are simplified diagrams illustrating how the microstructure of a shape memory material may change. Whilespecifically illustrate microstructure of shape memory alloys, shape memory polymers may exhibit a similar shape memory effect, as described below. Shape memory materials generally exhibit both a “shape memory effect” and a “pseudoplasticity effect.” Described briefly, the shape memory effect refers to the ability of a material to reverse material deformation in response to a temperature-induced state (e.g., phase) transformation. The pseudoelasticity effect refers to the ability of a material to reverse material deformation in response to a stress-induced state (e.g., phase) transformation, such as induced by the application of an external load.

Referring now to, a shape memory alloy may transform from an original austenitic phase (i.e., a high-temperature phase) to a martensitic phase (i.e., a low-temperature phase) upon cooling. The phase transformation from austenite to martensite may be spontaneous, diffusionless, and temperature dependent. The transition temperatures from austenite to martensite and vice versa vary for different shape memory alloy compositions. For example, the material composition of the shape memory alloy may be selected and/or tailored such that a first transition temperature (e.g., martensite finish temperature (M)) of a shape memory alloy occurs within a range of from about −140° C. to about 0° C., and a second transition temperature (e.g., austenite finish temperature (A)) of the shape memory alloy occurs within a range of from about 0° C. to about 200° C. Different material compositions of shape memory alloys and the transition temperatures are described in Minjuan Wang et al.,22(2) Progress in Natural Science: Materials International 130-138 (2012), available: sciencedirect.com/science/article/pii/S1002007112000330, the entire contents of which is hereby incorporated herein by this reference.

The phase transformation from austenite to martensite occurs between a first temperature (M), at which austenite begins to transform to martensite and a second, lower temperature (M), at which only martensite exists. As shown in, initially, the crystal structure of martensite is heavily twinned and may be deformed by an applied stress such that the material takes on a new size and/or shape. After the applied stress is removed, the material retains the deformed size and/or shape. However, upon heating, martensite may transform and revert to austenite. The phase transformation occurs between a first temperature (A) at which martensite begins to transform to austenite and a second, higher temperature (A) at which only austenite exists. Upon a complete transition to austenite, the element returns to its original “remembered” size and/or shape. As used herein, the term “remembered” refers to a configuration to which a material returns spontaneously responsive to a temperature change. Upon a second cooling process and transformation from austenite to martensite, the crystal structure of the martensitic phase is heavily twinned and may be deformed by an applied stress such that the material takes on at least one of a new size and/or shape. The size and/or shape of the material in the previously deformed martensitic phase are not remembered from the initial cooling process. This shape memory effect may be referred to as a one-way shape memory effect, such that the element exhibits the shape memory effect only upon heating as illustrated in.

Other shape memory alloys possess two-way shape memory, such that a material comprising such a shape memory alloy exhibits this shape memory effect upon heating and cooling. Shape memory alloys possessing two-way shape memory effect may, therefore, include two remembered sizes and shapes—a martensitic (i.e., low-temperature) shape and an austenitic (i.e., high-temperature) shape. Such a two-way shape memory effect is achieved by “training.” By way of example and not limitation, the remembered austenitic and martensitic shapes may be created by inducing non-homogeneous plastic strain in a martensitic or austenitic phase, by aging under an applied stress, or by thermomechanical cycling. With reference to, when a two-way shape memory alloy is cooled from an austenitic to a martensitic phase, some martensite configurations might be favored, so that the material may tend to adopt a preferred shape. By way of further non-limiting example, and without being bound by any particular theory, the applied stress may create permanent defects, such that the deformed crystal structure of the martensitic phase is remembered. After the applied stress is removed, the element retains the deformed size and/or shape. Upon heating, martensite may transform and revert to austenite between the first temperature (A) and the second, higher temperature (A). Upon a complete transition to austenite, the element returns to its original remembered size and shape. The heating and cooling procedures may be repeated such that the material transforms repeatedly between the remembered martensitic and the remembered austenitic shapes.

In some embodiments, the shape memory alloy material may comprise a nickel-titanium-niobium alloy that includes from about 40% to about 60% nickel by atomic weight, from about 30% to about 40% titanium by atomic weight, and from about 5% to about 20% Niobium by atomic weight. As specific non-limiting examples, the shape memory alloy may include NiTiNb, NiTiNb, and/or NiTiNb. In some embodiments, the first temperature (M), at which only martensite exists may be about −40° C., and the higher temperature (A) at which only austenite exists may be about 10° C. By way of non-limiting example, the shape memory alloy or shape memory polymer in a downhole application is to be selected to ensure that for a typical downhole temperature range, such as around 1° C. to around 250° C., or 1° C. to around 350° C., the shape memory alloy or shape memory polymer is in the austenite phase. The material properties of the shape memory alloy or shape memory polymer are to be selected to allow a desired change in the dimension in the martensitic phase.

A shape memory polymer may exhibit a similar shape memory effect. Heating and cooling procedures may be used to transition a shape memory polymer between a hard solid state and a soft solid state by heating the polymer above, for example, a melting point or a glass transition temperature (T) of the shape memory polymer and cooling the polymer below the melting point or glass transition temperature (T) as taught in, for example, U.S. Pat. No. 6,388,043, issued May 14, 2002, and titled “Shape Memory Polymers,” the entire disclosure of which is incorporated herein by this reference. The shape memory effect may be triggered by a stimulus which may be thermal, electrical, magnetic, or chemical.

are a simplified perspective view (), a simplified cross-sectional view (), and another simplified cross-sectional view () of a connection memberA in a first state and “permanent” or unmodified configuration, in accordance with embodiments of this disclosure.is a simplified cross-sectional view of the connection memberA taken along the A-A plane, andis a simplified cross-sectional view of the connection memberA taken along the B-B plane.

The connection memberA may be used to secure a brittle structure (e.g., brittle structure() or brittle structure()) to one or more additional components to form a downhole tool. The brittle structure may be any structure made of a brittle material, such as a shaft, housing, etc. The brittle structure may be a solid structure, such as a solid cylindrical structure made from a solid material, or may be a structure with an inner bore along the longitudinal axis, such as a tube like structure. A diameter of the inner bore may be less than 30%, less than 20%, less than 10% or less than 5% of an outer diameter of the brittle structure. The connection memberA may be made of or include a shape memory material, and the brittle structure (e.g., the brittle structure() and brittle structure()) may be made of or include a brittle material, such as glass, ceramic, graphite, hard metal, etc. In some embodiments, such as that shown in, the connection memberA may be in the form of a tubular structure configured (e.g., sized, shaped, oriented, and/or arranged) to surround at least a portion of a brittle material structure. While brittle structures are described, the disclosure is not so limited. For example, the connection membersA and the processes described herein can be utilized in connection with any type of material structure.

The connection memberA generally includes a bodycomprising a shape memory material configured to transition from a first state (e.g., austenite for shape memory alloys, or soft solid state for shape memory polymers) to a second state (e.g., martensite for shape memory alloys, or hard solid state for shape memory polymers) in response to application of a stimulus, such as temperature. The bodymay include one or more sidewalls. In various embodiments, the one or more sidewallsinclude a cylindrical shape with a singular sidewall (e.g., a hollow cylindrical shape, a right circular hollow cylindrical shape, a tapered circular cylindrical shape, without limitation). The body, and in various embodiments, the one or more sidewalls, define an opening(e.g., a cavity, through-hole, etc.) within the body. In the embodiment shown in, the openingextends from a first endof the bodythrough a second endof the bodyopposite the first end. In some embodiments, the openingmay be centered about a central longitudinal axisof the body.

A length (L) of the connection memberA is defined by a distance from the first endof the bodyto the second endof the body, opposite the first end. For example, the length Lof the connection memberA is defined by the distance from the first endof the bodyto the second endof the body. The one or more sidewallsmay include an exterior surfacedefining outer dimensions (e.g., an outer diameter (D)) of the connection memberA, and an interior surfacedefining interior dimensions (e.g., an inner diameter (D)) of the openingwithin the body. The length (L) and the dimensions (e.g., DOA and/or D) of the connection memberA may be selected and/or modified as desired.

Edges of the one or more sidewallsof the bodymay be chamfered, rounded, beveled, etc., at an end or ends thereof. For example, portions of the one or more sidewallsproximate the exterior surfaceand/or the interior surfaceof the bodyof the connection memberA may be chamfered, rounded, beveled, etc., at an end or ends thereof. In addition, the portions of the one or more sidewallsat the first endand/or the second endof the bodymay be chamfered, rounded, beveled, etc. Chamfered, beveled, and/or rounded edges may facilitate relative movement between the connection memberA and another structure, such as a brittle structure, while sliding the connection member on a corresponding portion of the brittle structure (,).

In, the connection memberA may be in a first state (e.g., the austenitic phase for shape memory alloys, or the soft solid state for shape memory polymers) and in a “permanent” or unmodified configuration. While the description below primarily references shape memory alloys, substantially the same behavior and processes apply to shape memory polymers by heating above and cooling below the glass transition temperature (T), rather than heating above the austenite finish temperature (A) and cooling below the martensite finish temperature (M). For example, the austenite phase of shape memory alloys may be analogous to the soft solid state of shape memory polymers, the martensite phase of shape memory alloys may be analogous to the hard solid state of shape memory polymers, and the glass transition temperature (T) of shape memory polymers may be analogous to a combination of the austenite finish temperature (A) and the martensite finish temperature (M) of shape memory alloys.

The connection memberA may be at a temperature above the austenite finish temperature (A) such that the connection memberA is in the austenitic phase. The connection memberA may be at about room temperature (about 20° C.), and the austenite finish temperature (A) may be about 5° C. In the austenitic phase, the connection memberA may exhibit one or more dimensions (e.g., inner diameter (D) or outer diameter (D)) that would cause an interference fit between the connection memberA and at least a portion of the brittle structure() or(). As non-limiting examples, the connection memberA (in the austenitic phase) may exhibit an inner diameter (D) within a range of from about 12 mm to about 20 mm (e.g., about 16 mm), an outer diameter (D) within a range of from about 17 mm to about 25 mm (e.g., about 21 mm), and a length (L) within a range of from about 12 mm to about 20 mm (e.g., about 16 mm).

In embodiments in which the connection memberA comprises a shape memory polymer, the connection memberA may be at a temperature above the glass transition temperature (T) such that the polymer is in a soft solid state. The connection memberA may similarly exhibit dimensions (e.g., inner diameter (D) or outer diameter (D)) that would cause an interference fit between the connection memberA and at least a portion of the brittle structure() or the brittle structure().

In some embodiments, at least a portion of the brittle structure() is approximately cylindrical and the connection memberA forms a tubular structure (e.g., a sleeve), the inner diameter (D) of the openingwithin the bodyof the connection memberA (before a downhole tool including the brittle structureis assembled) may be slightly smaller than the outer diameter of the brittle structure(e.g., a ceramic shaft). For example, the inner diameter (D) of the openingmay be from about 0.005% smaller to about 1% smaller than the outer diameter of the corresponding portion of the brittle structure, such as from about 0.05% smaller to about 0.5% smaller than the outer diameter of the corresponding portion of the brittle structure. As non-limiting examples of values, the inner diameter (D) of the openingmay be from about 0.001 inch (0.0254 mm) to about 0.1 inch (2.54 mm) smaller than the outer diameter of the corresponding portion of the brittle structure, such as from about 0.02 inch (0.508 mm) to about 0.060 inch (1.524 mm) smaller than the outer diameter of the corresponding portion of the brittle structure. In some embodiments, the brittle structure, and/or the connection memberA may include ridges or other textured surfaces to improve retention or alignment between the brittle structureand the connection memberA upon phase transition of the connection member. The inner diameter of connection memberA defines a surface (surface corresponding to the inner diameter). In the first state and unmodified configuration of connection memberA, the surface is secured to the corresponding portion of brittle structure.

In additional embodiments, the brittle structure() may be, for example, a brittle housing or a shaft that includes a cavity on one or more ends of the housing or shaft. The cavity may be sized and shaped to receive the connection memberA, and the connection memberA forms a tubular structure (e.g., a sleeve) sized and shaped to fit within the cavity of the brittle structure, the outer diameter (D) of the bodyof the connection memberA (before the downhole tool including the brittle structureis assembled) may be slightly larger than the inner diameter of the cavity within the brittle structure. For example, the outer diameter (D) of the bodyof the connection memberA may be from about 0.005% larger to about 1% larger than the inner diameter of the cavity within the brittle structure, such as from about 0.05% larger to about 0.5% larger than the cavity within the brittle structure. As non-limiting examples of values, the outer diameter (D) of the bodyof the connection memberA may be from about 0.001 in (0.0254 mm) to about 0.1 in (2.54 mm) larger than the inner diameter of the cavity within the brittle structure, such as from about 0.02 in (0.508 mm) to about 0.060 in (1.524 mm) larger than the inner diameter of the cavity of the brittle structure. In some embodiments, the brittle structure, and/or the connection memberA may include ridges or other textured surfaces to improve retention or alignment between the brittle structureand the connection memberA.

In embodiments in which the connection memberA comprises a shape memory alloy, the connection memberA may be cooled to a temperature below the martensite finish temperature (M) for shape memory alloys, such that the connection memberA changes state (e.g., phase) from austenite () to martensite (and, connection memberB). In embodiments in which the connection memberA comprises a shape memory polymer, the connection memberA may be cooled to a temperature below the glass transition temperature (T), such that the connection memberA changes state from the soft solid state () to the hard solid state (, connection memberB).

are a simplified perspective view () and a simplified cross-sectional view () of the connection memberA in a second, different state (B) and a “permanent” or unmodified configuration (e.g., martensite, without limitation), in accordance with embodiments of this disclosure.is a simplified cross-sectional view of the connection memberB oftaken along the C-C plane.

The connection memberB may be at a temperature below the martensite finish temperature (M) such that the connection memberB is in a second, different state (e.g., the martensitic phase), and also in a “permanent” or unmodified configuration. The connection memberB may be cooled to about −40° C., and the martensite finish temperature (M) may be about −40° C. In the martensitic phase, the connection memberB may exhibit substantially the same dimensions as the connection memberA in the austenitic phase. In the martensitic phase, the dimensions of the connection memberB (e.g., the inner diameter (DIB), the outer diameter (D), and/or the length (L)) may be modified by applying stress to the connection memberB to plastically deform (change dimensions) the martensitic material. For example, the inner diameter (D), the outer diameter (D), and/or the length (L) of the connection memberB may be increased by, for example, forcing a shaping body made from a hardened material through the openingof the connection memberB. For example, the hardness of the hardened material of the shaping body may be higher than the hardness of the connection memberB (e.g., higher than the hardness of the interior surfacewithin the openingof the connection memberB). As a non-limiting example, the hardness of the hardened material of the shaping body may be greater than about 50 Rockwell C hardness (HRC). In addition, the hardened material has a larger outer diameter than the inner diameter (D) of the connection memberB, such that the inner diameter (D) of the connection memberB expands as the shaping body passes through the opening. The expansion of the openingof the connection memberB may shift the location of the shape memory material and may correspondingly increase the outer diameter (D) and/or the length (L) of the connection memberB.

In embodiments in which the connection memberB comprises a shape memory polymer, the connection memberB may be at a temperature below the glass transition temperature (T) such that the polymer is in a hard solid state. The connection memberB may exhibit substantially the same dimensions as the connection memberA in the soft solid state. In the hard solid state, the dimensions of the connection memberB (e.g., the inner diameter (D), the outer diameter (D), and/or the length (L)) may be modified by applying stress to the connection memberB to plastically deform the hard solid state polymer material, in substantially the same manner as discussed with respect to the connection memberB comprising a shape memory alloy. For example, a shaping body made from hardened material may be passed through (e.g., forced through) the openingof the connection memberB to expand the inner diameter (D) and/or to modify the outer diameter (D) and/or the length (L) of the connection memberB. In some embodiments, the shaping body may be forced through the openingalong the central longitudinal axisof the bodyto expand the inner diameter (DB).

Expanding the inner diameter (D) of openingof the connection memberB may be done in a single pass or multiple passes with multiple differently sized shaping bodies, depending on the desired resulting size of the inner diameter (DB) of the connection memberB. For example, a desired final inner diameter (D) of the openingof the connection memberB may be about 1.5 mm larger than the current inner diameter (D) (unmodified configuration) of the connection memberB. A first shaping body made of a hardened material (e.g., a first hardened steel ball) with a diameter of about 0.5 mm larger than the inner diameter (D) of the connection memberB may be forced through the openingsuch that the inner diameter (D) expands about 0.5 mm. Next, a second shaping body made of the hardened material (e.g., a second hardened steel ball) that is about 0.5 mm larger than the partially expanded inner diameter (D) and the first hardened steel ball may be forced through the partially expanded openingsuch that the partially expanded inner diameter expands about another 0.5 mm, for a total of about 1 mm expansion. Additionally, a third shaping body made of the hardened material (e.g., a third hardened steel ball) that is about 0.5 mm larger than the partially expanded inner diameter (D) and the second hardened steel ball may be forced through the partially expanded openingsuch that the partially expanded inner diameter (D) expands about another 0.5 mm to an expanded diameter (D), for a total of about 1.5 mm expansion. The expansion of the inner diameter (DB) of the connection memberB may also correspondingly increase the outer diameter (D) and/or the length (L) of the connection memberB, as shown in.

are a simplified perspective view () and a simplified cross-sectional view () of the connection memberB in the second state, but in a modified configurationC relative to the connection memberB, in accordance with embodiments of this disclosure.is a simplified cross-sectional view of the connection member oftaken along the D-D plane.

In, the connection memberC may remain at a temperature below the transition temperature (e.g., below the martensite finish temperature (M) for shape memory alloys, or below the glass transition temperature (T) for shape memory polymers), such that the connection memberC remains in the second state (e.g., the martensitic phase, or the hard solid state). The dimensions of the connection memberC, such as the inner diameter (D) of the opening, the length (L) of the body, and optionally the outer diameter (D) of the bodymay be different than (e.g., larger, smaller, or substantially the same size as) the corresponding dimensions of the connection memberB. For example, the inner diameter (D) may be larger than the inner diameter the inner diameter (D), the length (L) may be larger than the length (L), and/or the outer diameter (D) may be larger than the outer diameter (D).

In the second state (e.g., martensitic phase, or hard solid state) and in the expanded configuration, the connection memberC may exhibit one or more dimensions (e.g., inner diameter (D) or outer diameter (D)) that enables the connection memberC to easily move relative to the corresponding portion of the brittle structure() so the connection memberC can be positioned on or within the corresponding portion of the brittle structure.

For example, in embodiments in which the brittle structurecomprises a shaft including an outer diameter, the inner diameter (D) of the connection memberC may be larger than the outer diameter of the brittle structureto easily slide on the shaft. For example, the inner diameter (D) of the openingof the connection memberC may be from about 0.005% larger to about 5% larger than the outer diameter of the corresponding portion of the brittle structure, such as from about 0.1% larger to about 2% larger than the outer diameter of the corresponding portion of the brittle structure. As non-limiting examples of values, the inner diameter (D) of the connection memberC may be from about 0.001 in (0.0254 mm) to about 0.1 in (2.54 mm) larger than the outer diameter of the corresponding portion of the brittle structure, such as from about 0.01 in (0.254 mm) to about 0.05 in (1.27 mm) smaller than the outer diameter of the corresponding portion of the brittle structure.

In embodiments in which the brittle structurecomprises a housing or a shaft including a cavity that includes an inner diameter, the outer diameter (D) of the bodyof the connection memberC may be smaller than the inner diameter within the cavity of the brittle structureto easily slide within the cavity. For example, the outer diameter (D) of the bodyof the connection memberC may be from about 0.005% smaller to about 5% smaller than the inner diameter of the cavity within the brittle structure, such as from about 0.1% smaller to about 2% smaller than the inner diameter of the cavity within the brittle structure. As non-limiting examples of values, the outer diameter (D) of the connection memberC may be from about 0.001 in (0.0254 mm) to about 0.1 in (2.54 mm) smaller than the inner diameter of the cavity within the brittle structure, such as from about 0.01 in (0.254 mm) to about 0.05 in (1.27 mm) smaller than the inner diameter of the cavity within the brittle structure.

is a perspective view of a brittle structureand two of the connection membersC in the second state (e.g., martensitic, or hard solid state) and the modified configuration (e.g., expanded configuration), in accordance with embodiments of this disclosure. The brittle structuremay be, for example, a brittle material shaft (e.g., ceramic, hard metal, glass, graphite, etc.) that may form part of a downhole tool. The brittle structureincludes a first end portionand an opposite second end portionthat are each configured (e.g., sized, shaped, oriented, and/or arranged) to receive one of the connection membersC. As shown in, a central portionof the brittle structuremay exhibit a larger diameter than the first and second end portions,of the brittle structure. A first diameter of the first end portionmay be substantially the same as a second diameter of the second end portion. In addition, the first diameter and the second diameter may each be smaller than the inner diameter (D) of the openingswithin the connection membersC to facilitate placement of the connection membersC in the respective first and second end portions,of the brittle structure. The first and second end portions,of the brittle structureare shown as having a substantially constant diameter along a length (L1) of the brittle structuredefined by a distance from a first endof the first end portionto an opposite end of the second endof first end portion(e.g., in a direction parallel to a longitudinal axisof the brittle structure). However, in additional embodiments, the first and second end portions,may by tapered with radially wider portions proximate ends of the brittle structure. In further embodiments, each of the first and second end portions,may include a step feature proximate the respective second end () of the brittle structure that flares radially outward relative to a remainder of the respective first and second end portion,. Wide ends of a taper or wide steps proximate ends of the brittle structuremay further mechanically secure the connection membersC in place for a firm connection. The connection membersC may be positioned on the first and second end portions,of the brittle structure, as shown in.

is a simplified side cross-sectional view of one of the connection membersC ofpositioned on the first end portionof the brittle structure. The connection memberC is in the second state (e.g., martensitic, or hard solid state) and the modified configuration. Because the inner diameter (D) of the openingwithin the connection memberC is larger than the outer diameter (D) of the first end portionof the brittle structure, there is clearancebetween the interior surfaceof the connection memberC and an outer surfaceof the first end portion. The clearanceis sufficient to move the connection memberC relative to the first end portionand the brittle structure. In the second state the connection memberC may be positioned to be joined to the first end portionor may be removed from the first end portion. To remove the clearanceand secure the connection membersC to the first and second end portions,of the brittle structure, the assembly of the brittle structureand the connection membersC (e.g., the portion of the downhole tool) may be exposed to a temperature above the transition temperature (e.g., the austenite finish temperature (A), or the glass transition temperature (T)) of the shape memory material such that the connection membersC transition back to the first state (e.g., the austenitic phase, or the soft solid state, unmodified state).

is a perspective view of a downhole tool componentthat includes the brittle structureand two of the connection membersA placed on the first and second end portions,of the brittle structure, in accordance with embodiments of this disclosure. While two connection membersA are shown in, in additional embodiments, the downhole tool componentmay include a single connection memberA on one of the end portions (e.g., the first end portion). The connection membersA are in the first state (e.g., the austenitic phase, or the soft solid state) and the “permanent” or unmodified configuration. The connection membersC ofmay be subjected to heat, such as by placing the brittle structureincluding one or more of the connection membersC within an oven at a temperature above the transition temperature (e.g., above the austenite finish temperature (A), or above the glass transition temperature (T)). For example, the assembly including the brittle structureand the connection membersC may be placed in an oven at a temperature of about 200° C. for about 5 minutes or longer. Upon reaching and/or exceeding the austenite finish temperature (A), the shape memory material of the connection memberC returns to the first state (e.g., austenitic phase, soft solid state) and the “permanent” or unmodified configuration. As the connection membersC return to the first state, the size/configuration of the connection membersC () returns to the size/configuration of the connection membersA () to secure the connection membersA to the brittle structure.

is a simplified side cross-sectional view of the downhole tool componentofthat includes the brittle structureand one of the connection membersA positioned on the first end portionof the brittle structure. The connection memberA is in the first state (e.g., austenitic, or soft solid state) and the unmodified configuration. The inner diameter (D) of the openingwithin the connection memberC has been reduced, by applying heat, to match the outer diameter (D) of the first end portionof the brittle structure. Thus, the clearance() between the connection memberC and the first end portionhas been eliminated due to the material expansion of the connection memberC. In some embodiments, the length (L) of the first end portionof the brittle structuremay be substantially the same as the length Lof the connection memberA. In additional embodiments, the length (L) of the first end portionof the brittle structuremay be different than the length Lof the connection memberA.