SELF-ACTUATING DEVICE FOR CENTRALIZING AN OBJECT

Abstract

The invention is directed to the interventionless activation of wellbore devices using dissolving and/or degrading and/or expanding structural materials. Engineered response materials, such as those that dissolve and/or degrade or expand upon exposure to specific environment, can be used to centralize a device in a wellbore.

Claims

1. A centralizing device that is configured to be positioned about an outer surface of a bore member, said centralizing device includes a body, an active material selected from the group consisting of an expandable material and a degradable material, and first and second of well bore wall engagement members, said first and second well bore wall engagement members include one or more structures selected from the group consisting of a slat, a wing, a bow, a leaf, a ribbon, an extension and a rib, said first and second well bore wall engagement members configured to move from a non-deployed position to a deployed position, said active material configured to cause said first and second well bore wall engagement members to move from said non-deployed position to said deployed position, a maximum outer perimeter of said centralizing device is greater in size when said first and second well bore wall engagement members are in said deployed position as compared to when said first and second well bore wall engagement members are in said non-deployed position, at least a portion of said first and second well bore wall engagement members positioned farther from a central axis of said body when in said deployed position than when said first and second well bore wall engagement members are in said non-deployed position.

2. The centralizing device as defined in claim 1, wherein said first and second well bore wall engagement members are formed of a bendable material and said expandable material, said expandable material is connected to at least a portion of said bendable material, said expandable material is configured to cause said bendable material to bend when said expandable material is expanded.

3. The method as defined in claim 2, wherein said expansion of said expandable material causes said bendable metal material to expand or bow radially outward.

4. The centralizing device as defined in claim 1, wherein each of said first and second well bore wall engagement members includes a top and bottom surface, said top surface configured to engage an inner wall of said wellbore, an inner wall of a cavity, or an inner wall of a tube when said first and second well bore wall engagement members move to said deployed position, said bottom surface of at least one of said first and second well bore wall engagement members includes a recess, at least a portion of said recess includes said active material, at least a portion of said to surface of at least one of said first and second well bore wall engagement members is absent said active material.

5. The centralizing device as defined in claim 2, wherein each of said first and second well bore wall engagement members includes a top and bottom surface, said top surface configured to engage an inner wall of said wellbore, an inner wall of a cavity, or an inner wall of a tube when said first and second well bore wall engagement members move to said deployed position, said bottom surface of at least one of said first and second well bore wall engagement members includes a recess, at least a portion of said recess includes said active material, at least a portion of said to surface of at least one of said first and second well bore wall engagement members is absent said active material.

6. The centralizing device as defined in claim 3, wherein each of said first and second well bore wall engagement members includes a top and bottom surface, said top surface configured to engage an inner wall of said wellbore, an inner wall of a cavity, or an inner wall of a tube when said first and second well bore wall engagement members move to said deployed position, said bottom surface of at least one of said first and second well bore wall engagement members includes a recess, at least a portion of said recess includes said active material, at least a portion of said to surface of at least one of said first and second well bore wall engagement members is absent said active material.

7. The centralizing device as defined in claim 1, wherein said body of said centralizing device includes first and second end portions, said first and second end portions spaced apart from one another, a first end of said first and second well bore wall engagement members connected to said first end portion, a second end of said first and second well bore wall engagement members connected to said second end portion, said first and second well bore wall engagement members spaced from one another along a longitudinal axis of said centralizing device.

8. The centralizing device as defined in claim 2, wherein said body of said centralizing device includes first and second end portions, said first and second end portions spaced apart from one another, a first end of said first and second well bore wall engagement members connected to said first end portion, a second end of said first and second well bore wall engagement members connected to said second end portion, said first and second well bore wall engagement members spaced from one another along a longitudinal axis of said centralizing device.

9. The centralizing device as defined in claim 6, wherein said body of said centralizing device includes first and second end portions, said first and second end portions spaced apart from one another, a first end of said first and second well bore wall engagement members connected to said first end portion, a second end of said first and second well bore wall engagement members connected to said second end portion, said first and second well bore wall engagement members spaced from one another along a longitudinal axis of said centralizing device.

10. The centralizing device as defined in claim 1, wherein said active material includes said degradable material, said degradable material configured to degrade or dissolve when activated during said activating step, said degradation or dissolving of said degradable material configured to cause or allow said first and second well bore wall engagement members to move from said non-deployed position to said deployed position.

11. The centralizing device as defined in claim 4, wherein said active material includes said degradable material, said degradable material configured to degrade or dissolve when activated during said activating step, said degradation or dissolving of said degradable material configured to cause or allow said first and second well bore wall engagement members to move from said non-deployed position to said deployed position.

12. The centralizing device as defined in claim 8, wherein said active material includes said degradable material, said degradable material configured to degrade or dissolve when activated during said activating step, said degradation or dissolving of said degradable material configured to cause or allow said first and second well bore wall engagement members to move from said non-deployed position to said deployed position.

13. The centralizing device as defined in claim 1, wherein said first and second well bore wall engagement members are biased in said deployed position.

14. The centralizing device as defined in claim 2, wherein said first and second well bore wall engagement members are biased in said deployed position.

15. The centralizing device as defined in claim 10, wherein said first and second well bore wall engagement members are biased in said deployed position.

16. The centralizing device as defined in claim 1, wherein said centralizing device includes a retaining member that is at least partially formed of said degradable material, said retaining member configured to maintain at least one of said first and second well bore wall engagement members in said non-deployed position.

17. The centralizing device as defined in claim 2, wherein said centralizing device includes a retaining member that is at least partially formed of said degradable material, said retaining member configured to maintain at least one of said first and second well bore wall engagement members in said non-deployed position.

18. The centralizing device as defined in claim 10, wherein said centralizing device includes a retaining member that is at least partially formed of said degradable material, said retaining member configured to maintain at least one of said first and second well bore wall engagement members in said non-deployed position.

19. The centralizing device as defined in claim 1, wherein at least a portion of said active material is coated with a coating material that is formulated to delay said activation step.

20. The centralizing device as defined in claim 2, wherein at least a portion of said active material is coated with a coating material that is formulated to delay said activation step.

21. The centralizing device as defined in claim 10, wherein at least a portion of said active material is coated with a coating material that is formulated to delay said activation step.

22. The centralizing device as defined in claim 1, wherein said expandable material includes reactive particles dispersed in a polymer matrix.

23. The centralizing device as defined in claim 2, wherein said expandable material includes reactive particles dispersed in a polymer matrix.

24. The centralizing device as defined in claim 22, wherein said reactive particles have a concentration of 20-60 vol. % in said polymer matrix, said reactive particles formulated to react with water to form oxides, hydroxides, or carbonates and to expand in volume at least 50 vol. % when reacted with said water.

25. The centralizing device as defined in claim 23, wherein said reactive particles have a concentration of 20-60 vol. % in said polymer matrix, said reactive particles formulated to react with water to form oxides, hydroxides, or carbonates and to expand in volume at least 50 vol. % when reacted with said water.

26. The centralizing device as defined in claim 22, wherein said reactive particles include one or more materials selected from the group consisting of MgO, CaO, CaC, Mg, Ca, Li, Na, Fe, Al, Si, P, Zn, Ti, Li.sub.2O, K.sub.2O, Na.sub.2O, borates, and aluminosilicates.

27. The centralizing device as defined in claim 23, wherein said reactive particles include one or more materials selected from the group consisting of MgO, CaO, CaC, Mg, Ca, Li, Na, Fe, Al, Si, P, Zn, Ti, Li.sub.2O, K.sub.2O, Na.sub.2O, borates, and aluminosilicates.

28. The centralizing device as defined in claim 22, wherein said polymer matrix includes one or more polymers selected from the group consisting of polyester, nylon, polycarbonate, polysulfone, polyurea, polyimide, silanes, carbosilanes, silicone, polyarylate, polyimide, PEEK, PEI, epoxy, PPS, PPSU, and phenolic compounds.

29. The centralizing device as defined in claim 27, wherein said polymer matrix includes one or more polymers selected from the group consisting of polyester, nylon, polycarbonate, polysulfone, polyurea, polyimide, silanes, carbosilanes, silicone, polyarylate, polyimide, PEEK, PEI, epoxy, PPS, PPSU, and phenolic compounds.

30. The centralizing device as defined in claim 1, wherein said expandable material includes one or more of (i) a catalyst that is formulated to accelerate reaction of said reactive particles and (ii) strengthening fillers, diluting fillers, or combinations thereof that include one or more materials selected from the group consisting of fumed silica, silica, glass fibers, carbon fibers, carbon nanotubes, and other finely divided inorganic material.

31. The centralizing device as defined in claim 2, wherein said expandable material includes one or more of (i) a catalyst that is formulated to accelerate reaction of said reactive particles and (ii) strengthening fillers, diluting fillers, or combinations thereof that include one or more materials selected from the group consisting of fumed silica, silica, glass fibers, carbon fibers, carbon nanotubes, and other finely divided inorganic material.

32. The centralizing device as defined in claim 1, wherein said degradable material includes a base metal material and a plurality of particles disbursed in said degradable material, said particles constitute about 0.1-40 wt. % of said degradable material, said base metal material is magnesium, aluminum, magnesium alloy or aluminum alloy, said particles including one or more materials selected from the group consisting of iron, copper, titanium, zinc, tin, cadmium, calcium, lead, beryllium, nickel, carbon, iron alloy, copper alloy, titanium alloy, zinc alloy, tin alloy, cadmium alloy, lead alloy, beryllium alloy, and nickel alloy.

33. The centralizing device as defined in claim 10, wherein said degradable material includes a base metal material and a plurality of particles disbursed in said degradable material, said particles constitute about 0.1-40 wt. % of said degradable material, said base metal material is magnesium, aluminum, magnesium alloy or aluminum alloy, said particles including one or more materials selected from the group consisting of iron, copper, titanium, zinc, tin, cadmium, calcium, lead, beryllium, nickel, carbon, iron alloy, copper alloy, titanium alloy, zinc alloy, tin alloy, cadmium alloy, lead alloy, beryllium alloy, and nickel alloy.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Referring particularly to the drawings for the purposes of illustration only and not limitation:

[0061] FIG. 1 is a side view of an annular centralizer with expanding bow elements in an unexpanded configuration;

[0062] FIG. 2 is a side view of an annular centralizer with expanding bow elements in an expanded configuration;

[0063] FIG. 3 is a side cut-away view of one bow element that is formed of a structural material and an expandable structural material wherein the expanded material has not been caused to be expanded;

[0064] FIG. 4 is a side cut-away view of the bow element of FIG. 3 wherein the expanded material has been caused to be expanded to thereby cause the bow element to bow;

[0065] FIG. 5 is a side cut-away view of another bow element that is formed of a structural material and an expandable structural material wherein the expanded material has not been caused to be expanded;

[0066] FIG. 6 is a side cut-away view of the bow element of FIG. 5 wherein the expanded material has been caused to be expanded to thereby cause the bow element to bow;

[0067] FIG. 7 is a side cut-away view of another bow element that is formed of a structural material and an expandable structural material wherein the expanded material has not been caused to be expanded;

[0068] FIG. 8 is a side cut-away view of the bow element of FIG. 7 wherein the expanded material has been caused to be expanded to thereby cause the bow element to bow;

[0069] FIG. 9 is a side cut-away view of another bow element that is formed of a structural material and an expandable structural material and a degradable material wherein the expanded material has been caused to be expanded to thereby cause the bow element to bow and wherein the degradable material has not been caused to degrade;

[0070] FIG. 10 is a side cut-away view of the bow element of FIG. 9 wherein the degradable material is caused to degrade after the expanded material has been caused to be expand to thereby cause the bow element to move back to the unbowed position;

[0071] FIG. 11 is a side view of an annular centralizer with expanding bow elements in an unexpanded configuration wherein the bows are retained in an unbowed position by a degradable sleeve;

[0072] FIG. 12 is a side view of the annular centralizer of FIG. 11 in the expanded position wherein the degradable sleeve is dissolved and/or degraded to allow the bow elements to move to the bow position;

[0073] FIG. 13 is an illustration of core particles reacting under controlled stimulus, at which point the core particle will expand, expanding the fracture to enhance oil and gas recovery;

[0074] FIGS. 14a and 14b illustrate a non-limiting method of engineering a force delivery system for expanding into fracture opening, namely constraint by a semi-permeable or impermeable matrix;

[0075] FIGS. 15a and 15b are schematics of shape memory alloy syntactic, as well as actual syntactic metal;

[0076] FIG. 16 illustrates a typical cast microstructure with grain boundaries (500) separating grains (510);

[0077] FIG. 17 illustrates a detailed grain boundary (500) between two grains (500) wherein there is one non-soluble grain boundary addition (520) in a majority of grain boundary composition (530) wherein the grain boundary addition, the grain boundary composition, and the grain all have different galvanic potentials and different exposed surface areas;

[0078] FIG. 18 illustrates a detailed grain boundary (500) between two grains (510) wherein there are two non-soluble grain boundary additions (520 and 540) in a majority of grain boundary composition (530) wherein the grain boundary additions, the grain boundary composition, and the grain all have different galvanic potentials and different exposed surface areas;

[0079] FIGS. 19-21 show a typical cast microstructure with galvanically-active in situ formed intermetallic phase wetted to the magnesium matrix; and,

[0080] FIG. 22 shows a typical phase diagram to create in situ formed particles of an intermetallic Mg.sub.x(M) where M is any element on the periodic table or any compound in a magnesium matrix and wherein M has a melting point that is greater than the melting point of Mg.

DESCRIPTION OF THE INVENTION

[0081] The present invention relates to methods and constructions for centering components within a well, particularly an oil or gas well, more particularly to centralizers for use in drilling and completion operations, and still more particularly to centralizer devices which employ interventionless mechanisms to deploy and retract a tube, liner, casing, etc. in a drilling or well operation.

[0082] The present invention uses materials that have been developed to react and/or respond to wellbore conditions. These materials can be used to create various responses in a wellbore, such as dissolution, structural degradation, shape change, expansion, change in viscosity, reaction (heating or even explosion), changed magnetic or electrical properties, and/or others of such materials. These responses can be triggered by a change in temperature from the surface to a particular location in the wellbore, change in pH about the material, controlling salinity about the region of the material, addition or presence of a chemical (e.g., CO.sub.2, etc.) to react with the material, and/or electrical stimulation (e.g., introducing an electrical current, current pulse, etc.) to the material, among others. These materials can be used in conjunction with a centralizer to activate and/or deactivate the centralizer.

[0083] When structural expandable materials are used with a centralizer, these expandable structural materials can be used to apply forces to the bow structure of a centralizer, thereby causing such bow structures to deploy once the centralizer is placed in a desired position in the wellbore. Similarly, when a degradable structural material is used with the centralizer, such as, but not limited to, a ring, sleeve, spring, bolt, rivet, bracket, pin, clip, etc., such degradable structural material can be used to retain, compress and/or constrain a centralizer utilizing spring-loaded wings or bows. In such a configuration, when the degradable structural material is caused to dissolve and/or degrade (thereby removing or weakening the degradable structural material) the spring-loaded wings or bows will be allowed to actuate and deploy of on the centralizing device. By combining degradable materials on a centralizing device, a novel centralizing device can be created that can be automatically deployed and/or retracted in a controlled manner in a wellbore. As can also be appreciated, after the centralizing device has been deployed, the centralizing device can be caused to be disabled by the degradable structural material. For example, a degradable structural material can be in the form of a retaining pin that can be designed to dissolve and/or degrade to thereby cause the pin to fail, which pin failure causes the spring force on the wings or bows to be reduced or lost. As can be appreciated, many other or additional components of the centralizing device can be formed of a degradable structural material to cause the centralizing device to be activated or deactivated. As can be appreciated, one type of degradable structural material can be used to cause the activation of the centralizing device, and a different degradable structural material can be used to disable or deactivate the centralizing device; however, this is not required.

[0084] Referring now to FIG. 1, there is illustrated a centralizer 200 in a non-deployed position or unexpanded position. The centralizer includes first and second end portions 210, 220 that are connected together by a plurality of bendable ribs 300. As defined herein, the bendable ribs are one type of well bore wall engagement member that can be included on the centralizer. The end portions each have a cylinder shape having a cavity 212, 222 that is configured to fit about a pipe. The ribs having a generally rectangular shape and are spaced from one another. FIG. 2 illustrates the centralizer in the deployed or expanded position. The ribs in the centralizer can be caused to controllably deploy using an expandable material. As can be appreciated, the centralizer can have other configurations wherein a portion of the centralizer moves from a non-deployed to a deployed position. As illustrated in FIGS. 1 and 2, the maximum outer perimeter of the centralizer in FIG. 2 is greater in size to the maximum outer perimeter of the centralizer in FIG. 1. The increase in the size of the outer perimeter of the centralizer in FIG. 2 is the result of the outward bowing of the ribs 300. The amount of bowing of the ribs caused by the expandable material is non-limiting. In one non-limiting embodiment, the increase in the size of the outer perimeter of the centralizer is a result of the one or more well bore wall engagement members on the centralizer (e.g., slat, wing, bow, leave, ribbon, extension, rib, etc.) moving from the non-deployed position to the deployed position is at least about 0.1 inches, typically at least about 0.25 inches, and more typically at least about 0.75 inches. In one specific non-limiting aspect of the invention, the increase in the size of the outer perimeter of the centralizer as a result of the one or more well bore wall engagement members on the centralizer moving from the non-deployed position to the deployed position is about 0.1-20 inches (and all values and ranges therebetween), and typically 0.25-10 inches. In another specific non-limiting aspect of the invention, the percent increase in the size of the outer perimeter of the centralizer as a result of the one or more well bore wall engagement members on the centralizer moving from the non-deployed position to the deployed position is about 2-300% (and all values and ranges therebetween), and typically 5-100%. As can be appreciated, the amount of bowing of the ribs caused by the expandable material can be controlled by various factors (e.g., amount of expandable material used, the thickness of the bendable material used to form the ribs, the type of material used to form the bendable material used to form the ribs, the type of material used to form the expandable material, the degree to which the expandable material is caused to expand, the configuration of the ribs, the use of slots or other structures in the bendable material used to form the ribs, etc.).

[0085] Referring now to FIGS. 3 and 4, there is illustrated a cross-section of one non-limiting configuration of rib 300. As illustrated in FIGS. 3 and 4, the rib is formed of a bendable material 310 such as a metal and includes a layer of expandable material 320. The expandable material can be a) mechanically connected to the bendable material (e.g., friction fit, screw, rivet, bolt, etc.), b) connected by an adhesive, c) connected by welding to the bendable material, d) connected by lamination to the bendable material and/or e) cast to the bendable material. When the expandable material is caused to expand, the expandable material applies a force to the bendable material and causes the bendable material to bend or bow as illustrated in FIG. 4. The bending of the ribs of the centralizer results in the centralizing moving to the deployed position and centralizing a pipe in a well bore.

[0086] Referring now to FIGS. 5 and 6, cross section of another non-limiting rib 300 is illustrated. The rib is formed of a bendable material 310 (such as a metal) and includes a layer of expandable material 320. The bendable material includes one or more notches or depressions 330 that are filled with the expandable material. The expandable material can be a) mechanically connected to the bendable material (e.g., friction fit, screw, rivet, bolt, etc.), b) connected by an adhesive, c) connected by welding to the bendable material, d) connected by lamination to the bendable material and/or e) cast to the bendable material. As illustrated by the arrows in FIGS. 5 and 6, when the expandable material is caused to expand, the expandable material applies a force to the bendable material and causes the bendable material to bend or bow as illustrated in FIG. 6. The bending of the ribs of the centralizer results in the centralizing move to the deployed position and centralizing a pipe in a well bore.

[0087] Referring now to FIGS. 7 and 8, cross section of another non-limiting rib 300 is illustrated. The rib is formed of a bendable material 310 (such as a metal) and includes two regions of expandable material 340, 342. The bendable material includes one or more notches or depressions 350, 352 located at each end portion of the rib. The one or more notches or depressions are filled with the expandable material. The expandable material can be a) mechanically connected to the bendable material (e.g., friction fit, screw, rivet, bolt, etc.), b) connected by an adhesive, c) connected by welding to the bendable material, d) connected by lamination to the bendable material and/or e) cast to the bendable material. As illustrated by the arrows in FIG. 8, when the expandable material is caused to expand, the expandable material applies a force to the bendable material and causes the bendable material to bend or bow. The bending of the ribs of the centralizer results in the centralizing move to the deployed position and centralizing a pipe in a well bore.

[0088] Referring now to FIGS. 9 and 10, the rib 300 can optionally include a degradable metal 360, 362 that is located adjacent to expandable material 370, 372 that is located in notches or depressions 380, 382. After the rib has been caused to bend by the expansion of the expandable material as illustrated in FIG. 9, the rib can be allowed to flex or move partially or fully to the unbent position by reducing the bending force on the bendable material that is caused by the expansion of the expandable material. Such reduction in force as illustrated by the arrow in FIG. 10 can be accomplished by causing the degradable metal to dissolve and/or degrade as illustrated in FIG. 10. The partial or full removal of the degradable metal from the rib results in the bending force being applied by the expanded expandable material to be reduced or eliminated, thereby allowing the rib to unbend or bend partially or fully back to its position prior to the expansion of the expandable material. The ribs can be formed of a memory metal to facilitate in the movement of the rib back to the unbent position; however, this is not required. The expandable material and the degradable metal can be a) mechanically connected to the bendable material (e.g., friction fit, screw, rivet, bolt, etc.), b) connected by an adhesive, c) connected by welding to the bendable material, d) connected by lamination to the bendable material and/or e) cast to the bendable material.

[0089] The non-limiting embodiments illustrated in FIGS. 3-10 merely illustrate a few of the many configurations that can be used to cause the well bore wall engagement members on the centralizer (e.g., slat, wing, bow, leave, ribbon, extension, rib, etc.) to bend and optionally unbend.

[0090] Referring now to FIGS. 11 and 12, there is illustrated another type of centralizer 200. The ribs 300 of the centralizer are configured to move to a bent state when no constraining force is applied to the ribs. The ribs are maintained in an unbent state by use of a retaining member 390. As such, the ribs are biased in a bent state, but are retained in the unbent state by the retaining member. As can be appreciated, the ribs may not be biased in a bent state, but can be activated (e.g., temperature change, pH change, chemistry change, electric stimulation, etc.) to move to the bent state by some activation stimulus after the retaining member has been partially or fully dissolved and/or degraded. As can be appreciated, such activation can occur prior to, during, or after the retaining member has been partially or fully dissolved and/or degraded. As also can also or alternatively be appreciated, the ribs can be caused to be moved to the bent state by use of an expandable material as illustrated in FIGS. 3-9; however, this is not required. As illustrated in FIG. 6a, the retaining member 400 partially or fully encircles all or a portion of the ribs. As can be appreciated, other retaining member configurations can be used to maintain the ribs in an unbent position. The retaining member is made of a degradable metal. When the degradable metal partially or fully dissolves and/or degrades, the retaining force of the ribs is reduced or eliminated, thereby enabling the ribs to move from the non-deployed to the deployed position.

[0091] Generally, the expandable material is typically configured to expand less than 5 vol. % in the well bore prior to being activated, typically expand less than 2 vol. % in the well bore prior to being activated, more typically expand less than 1 vol. % in the well bore prior to being activated, and still more typically expand less than 0.5 vol. % in the well bore prior to being activated. Likewise, the degradable material is typically configured to degrade less than 5 vol. % in the well bore prior to being activated, typically degrade less than 2 vol. % in the well bore prior to being activated, more typically degrade less than 1 vol. % in the well bore prior to being activated, and still more typically degrade less than 0.5 vol. % in the well bore prior to being activated. The activation of the expandable or the degradable material can be accomplished by one or more events selected from the group consisting of a) change in temperature about the expandable material or the degradable material from the surface of the well bore to a particular location in the well bore, b) change in pH about the expandable material or the degradable material, c) change in salinity about the expandable material or the degradable material, d) exposure of the expandable material or the degradable material to an activation element or compound, e) electrical stimulation of the expandable material or the degradable material, f) exposure of the expandable material or the degradable material to a certain sound frequency, and/or g) exposure of the expandable material or the degradable material to a certain electromagnetic frequency.

Expandable Materials that can be Used in a Centralizer.

[0092] Non-limiting examples of expandable materials that can be used in a centralizer are set forth below:

Example 1

[0093] A high temperature resistant and tough thermoplastic polysulfone with 25% volumetric loading of expanding Fe micro powder showed an unconstrained volumetric expansion of 50% is possible in a solution of 2% KCl at 190° C. over a period of 50 hours.

Example 2

[0094] A 30% volumetric loading of expandable metal CaO powder in epoxy binder milled and sieved to 8/16 mesh size showed a 24% volumetric expansion while under 3,000 psig fracture load stress when exposed to a solution of 2% KCl, 0.5M NaCO.sub.3 at 60-80° C. in a period of 1 hour.

Example 3

[0095] A 30% volumetric loading of expandable metal CaO powder in 6,6 nylon binder under 2,500 psig fracture load stress when exposed to a solution of 2% KCl, 0.5M NaCO.sub.3 at 60-80° C. in a period of 1 hour.

[0096] The high force reactive expandables that are used in the centralizer are engineered to act as a force delivery system to cause the centralizer to move to a partially or fully deployed position. The deployment of the high force reactive expandables can be at least partially controlled. Such control can be accomplished by coating, encapsulating, microstructure placement and alignment and/or otherwise shielding the expandable core particle with a dissolving/triggerable surface coating that will dissolve and/or degrade under specific formation conditions. The volumetric expansion of the expandable core particle in such an aspect of the invention can then be constrained to deliver force.

[0097] FIGS. 13 and 14 illustrate non-limiting methods for controlling the volumetric expansion of the expandable core particle. The core particles can be designed to react under controlled stimulus, at which point the core will expand. One non-limiting feature of the invention is the controlling of the timing/trigger, and/or amount and/or speed of the expanding reaction. Control/trigger coatings can also be used (e.g., temperature activated coatings, chemically activated engineered response coatings, etc.). Control of the protective layer thickness and/or composition can be used to dictate where and under what conditions the reactive composite core particle will be exposed to formation fluids. Once exposed, the expandable materials will expand volumetrically and, with properly engineered constraint, direct the volumetric expansion as a normal force to cause the centralizer to move to a partially or fully deployed position.

[0098] Referring to FIG. 13, there is illustrated an expandable material 10 that includes a protective layer or surface coating 20, an expandable core 30 which can include, but is not limited to, an expanding metal, structural filler, and activator in a diluent/binder to control mechanical properties. The protective layer is generally formulated to dissolve and/or degrade when exposed to a controlled external stimulus (e.g., temperature and/or pH, chemicals, etc.). The protective layer is used to control activation of the expanding of the expandable core 30, which upon expansion becomes expanded core 40. Protective layer 20 can be comprised of one or more of, but not limited to, polyester, polyether, polyamine, polyamide, polyacetal, polyvinyl, polyureathane, epoxy, polysiloxane, polycarbosilane, polysilane, and polysulfone. Protective layer 20 can range in thickness from, but not limited to, 0.1-1 mm and any value or range therebetween, and generally range from 10 μm to 100 μm and any value or range therebetween. Composition of the expandable core 30 can include an expanding material that can be, but is not limited to, Ca, Li, CaO, Li.sub.2O, Na.sub.2O, Fe, Al, Si, Mg, K.sub.2O and Zn. The expandable material can range in volumetric percentage of expandable core 30 of, but not limited to, 5-60% and any value or range therebetween, and generally range from 20-40% and any value or range therebetween. Composition of the expandable core 30 may or may not include a structural filler that can be, but is not limited to, fumed silica, silica, glass fibers, carbon fibers, carbon nanotubes and other finely divided inorganic material. Structural filler can range in volumetric percentage of expandable core 30 of, but not limited to, 1-30% and any value or range therebetween, and generally range from 5-20% and any value or range therebetween. Composition of expandable core 30 may or may not include an activator that can be, but is not limited to, peroxide, metal chloride, or galvanically-active material. Composition of expandable core 30 can include a diluent/binder that can be, but is not limited to, polyacetals, polysulfones, polyurea, epoxys, silanes, carbosilanes, silicone, polyarylate, and polyimide. Binder can range in volumetric percentage of expandable core 30 of, but not limited to, 50-90% and any value or range therebetween, and generally range from 50-70% and any value or range therebetween. Expandable core 30 expands into expanded core 40 in the range of 5-50% volumetric expansion and any value or range therebetween, and generally in the range of 5-20% and any value or range therebetween.

[0099] Referring now to FIGS. 14a and 14b, a non-limiting method of engineering force delivery system to cause the centralizer to move to a partially or fully deployed position is illustrated, namely constraint by a semi-permeable or impermeable sleeve (FIG. 14a). Constraining sleeve translates triggered expansion into a uniaxial force (FIG. 14b). The protective layer 20 (in the form of a plug) is formulated to dissolve and/or degrade or become permeable when exposed to controlled external stimulus (temperature, pH, certain chemicals, etc.) to cause the protective layer to dissolve and/or degrade or otherwise breakdown, thereby controlling activation of expanding of the expandable core 30. Upon expansion to expanded core 40 constraining sleeve 50 directs expansion forces parallel to constraining sleeve.

[0100] The protective layer 20 (when used) can be comprised of one or more of, but not limited to, polyester, polyether, polyamine, polyamide, polyacetal, polyvinyl, polyureathane, epoxy, polysiloxane, polycarbosilane, polysilane, and polysulfone. Protective layer 20 can range in thickness from, but is not limited to, 0.1-1 mm, and generally range from 10-100 μm. Composition of expandable core 30 can include an expanding material that can be, but is not limited to, Ca, Li, CaO, Li.sub.2O, Na.sub.2O, Fe, Al, Si, Mg, K.sub.2O and Zn. The expandable material can range in volumetric percentage of expandable core 30 of, but is not limited to, 5-60%, and generally range from 20-40%. The composition of expandable core 30 may or may not include a structural filler that can be, but is not limited to, fumed silica, silica, glass fibers, carbon fibers, carbon nanotubes and other finely divided inorganic material. The structural filler can range in volumetric percentage of expandable core 30 of, but is not limited to, 1-30%, and generally range from 5-20%. The composition of expandable core 30 may or may not include an activator that can be, but is not limited to, peroxide, metal chloride, or galvanically active material. The composition of expandable core 30 can include a diluent/binder that can be, but is not limited to, polyacetals, polysulfones, polyurea, epoxies, silanes, carbosilanes, silicone, polyarylate, and polyimide. The binder can range in volumetric percentage of expandable core 30 of, but is not limited to, 50-90%, and generally range from 50-70%. Expandable core 30 is configured to expand into expanded core 40 in the range of 5-50% volumetric expansion, and generally in the range of 5-20%. The constraining sleeve 50 can include, but is not limited to, one or more high temperature-high strength materials such as polycarbonate, polysulfones, epoxies, polyimides, inert metals (e.g., Cu with leachable salts), etc. Constraining layer 50 can range in thickness from, but not limited to 0.1 μm to 1 mm, and generally range from 10-100 μm. The configuration of the constraining sleeve 50 is non-limiting, as other shape configurations are applicable for imparting directional expansion. Generally, the constraining sleeve is designed to not rupture during the expansion of expandable core 30; however, this is not required. In one non-limiting arrangement, the constraining sleeve is designed to not rupture and may or may not deform during the expansion of expandable core 30. The constraining sleeve can include one or more side openings; however, this is not required. The one or more side opening can be used as an alternative or in addition to the one or more end openings in the constraining sleeve. The one or more side openings (when used) can optionally include a protective coating that partially or fully covers the side opening.

[0101] FIGS. 15a and 15b illustrate the construction of shape memory expandables derived from metal- or plastic-coated hollow sphere 60 or syntactic 100. Shape memory expandables can include, but are not limited to, a hollow sphere core 70 and a plastic or metal coating or composite 80. The shape memory composites 60 and 100 are compressed under temperature promoting plastic yield and then cooled while compressed, locking in potential mechanical force to produce shape memory expandables. Under the external stimulus of temperature above glass transition temperatures, the shape memory composites return to their uncompressed states exerting up to 30-70 Ksi forces and any value or range therebetween. Hollow sphere core 70 can be comprised of, but is not limited to, glass (borosilicate, aluminosilicate, etc.), metal (magnesium, zinc, etc.), or plastic (phenolic, nylon, etc.), which range in sizes from 10 nm to 5 mm and any value or range therebetween, and generally range from 10-100 μm. Coating or composite matrix 80 can be comprised of one or more of, but not limited to, metal (titanium, aluminum, magnesium, etc.), or plastic (epoxy, polysulfone, polyimides, polycarbonate, polyether, polyester, polyamine, polyvinyl, etc.), which range in composite volume percentages from 1-70% and any value or range therebetween. Actual compressed and non-compressed syntactics are illustrated and, in this case, the compression is reversed using the shape memory effects delivering forces as high as 30-70 Ksi. Advantages of the shape memory alloy include low density, very high actuation force, and/or very controllable actuation.

Expandable Chemistries

[0102] In still another non-limiting aspect of the invention, a feature in the expandable design of the high force reactive expandables is the active expandable material. Active expandable material having reactive mechanical or chemical changes occurring in the temperature range of at least 25° C. (e.g., 30-350° C., 30-250° C., etc. and all values and ranges therebetween) and having a volumetric expansion of over 10% (e.g., 20-400%, 30-250%, etc. and all values and ranges therebetween) can be utilized in the present invention. Table 1 lists some non-limiting specific reactions that are suitable for use in the structural expandable materials and for the expandable proppants:

TABLE-US-00001 TABLE 1 CaO .fwdarw. CaCO3 119% expansion  Fe .fwdarw. Fe2O3 115% expansion  Si .fwdarw. SiO2 88% expansion Zn .fwdarw. ZnO 60% expansion Al .fwdarw. Al2O3 29% expansion

[0103] The formation of hydroxides and/or carbonates can potentially result in larger expansion percentages.

[0104] In still another non-limiting aspect of the invention, there is provided a method to control the rate and/or completion of the oxidation reaction through 1) control over active particle surface area, 2) binder/polymer permeability control, 3) the addition of catalysis (e.g., AlCl.sub.3—used to activate iron surfaces), and/or 4) control over water permeability/transport to the metal surface. Ultrafine and near nanomaterials, as well as metallic flakes (which expand primarily in one direction) can be used to tailor the performance and response of these expandable materials. Mechanical properties such as modulus, creep strength, and/or fracture strength can also or alternatively be controlled through the addition of fillers and diluents (e.g., oxides, etc.) and semi-permeable engineering polymers having controlled moisture solubility.

Degradable Materials that can be Used in a Centralizer.

[0105] Non-limiting examples of degradable materials that can be used in a centralizer are set forth below:

Example 1

[0106] An AZ91D magnesium alloy having 9 wt. % aluminum, 1 wt. % zinc and 90 wt. % magnesium was melted to above 800° C. and at least 200° C. below the melting point of nickel. About 7 wt. % of nickel was added to the melt and dispersed. The melt was cast into a steel mold. The degradable metal exhibited a tensile strength of about 14 Ksi, an elongation of about 3%, and shear strength of 11 Ksi. The degradable metal dissolved and/or degraded at a rate of about 75 mg/cm.sup.2-min in a 3% KCl solution at 90° C. The material dissolved and/or degraded at a rate of 1 mg/cm.sup.2-hr in a 3% KCl solution at 21° C. The material dissolved and/or degraded at a rate of 325 mg/cm.sup.2-hr. in a 3% KCl solution at 90° C.

Example 2

[0107] An AZ91D magnesium alloy having 9 wt. % aluminum, 1 wt. % zinc and 90 wt. % magnesium was melted to above 800° C. and at least 200° C. below the melting point of copper. About 10 wt. % of copper alloyed to the melt and dispersed. The melt was cast into a steel mold. The degradable metal exhibited a tensile yield strength of about 14 Ksi, an elongation of about 3%, and shear strength of 11 Ksi. The degradable metal dissolved and/or degraded at a rate of about 50 mg/cm.sup.2-hr. in a 3% KCl solution at 90° C. The material dissolved and/or degraded at a rate of 0.6 mg/cm.sup.2-hr. in a 3% KCl solution at 21° C.

Example 3

[0108] An AZ91D magnesium alloy having 9 wt. % aluminum, 1 wt. % zinc and 90 wt. % magnesium was melted to above 700° C. About 16 wt. % of 75 um iron particles were added to the melt and dispersed. The melt was cast into a steel mold. The degradable metal exhibited a tensile strength of about 26 Ksi, and an elongation of about 3%. The degradable metal dissolved and/or degraded at a rate of about 2.5 mg/cm.sup.2-min in a 3% KCl solution at 20° C. The material dissolved and/or degraded at a rate of 60 mg/cm.sup.2-hr in a 3% KCl solution at 65° C. The material dissolved and/or degraded at a rate of 325 mg/cm.sup.2-hr. in a 3% KCl solution at 90° C.

Example 4

[0109] An AZ91D magnesium alloy having 9 wt. % aluminum, 1 wt. % zinc and 90 wt. % magnesium was melted to above 700° C. About 2 wt. % 75 um iron particles were added to the melt and dispersed. The melt was cast into steel molds. The material exhibited a tensile strength of 26 Ksi, and an elongation of 4%. The material dissolved and/or degraded at a rate of 0.2 mg/cm.sup.2-min in a 3% KCl solution at 20° C. The material dissolved and/or degraded at a rate of 1 mg/cm.sup.2-hr in a 3% KCl solution at 65° C. The material dissolved and/or degraded at a rate of 10 mg/cm.sup.2-hr in a 3% KCl solution at 90° C.

Example 5

[0110] An AZ91D magnesium alloy having 9 wt. % aluminum, 1 wt. % zinc and 90 wt. % magnesium was melted to above 700° C. About 2 wt. % nano iron particles and about 2 wt. % nano graphite particles were added to the composite using ultrasonic mixing. The melt was cast into steel molds. The material dissolved and/or degraded at a rate of 2 mg/cm2-min in a 3% KCl solution at 20° C. The material dissolved and/or degraded at a rate of 20 mg/cm2-hr in a 3% KCl solution at 65° C. The material dissolved and/or degraded at a rate of 100 mg/cm2-hr in a 3% KCl solution at 90° C.

Example 6

[0111] A magnesium alloy that includes 9 wt. % aluminum, 0.7 wt. % zinc, 0.3 wt. % nickel, 0.2 wt. % manganese, and 2 wt. % calcium was added to the molten magnesium alloy. The magnesium alloy dissolved and/or degraded at a rate of 91 mg/cm.sup.2-hr. in the 3% KCl solution at 90° C. The magnesium alloy also dissolved and/or degraded at a rate of 34 mg/cm.sup.2-hr. in the 0.1% KCl solution at 90° C., a rate of 26 mg/cm.sup.2-hr. in the 0.1% KCl solution at 75° C., a rate of 14 mg/cm.sup.2-hr. in the 0.1% KCl solution at 60° C., and a rate of 5 mg/cm.sup.2-hr. in the 0.1% KCl solution at 45° C.

Example 7

[0112] 1.5-2 wt. % zinc, 1.5-2 wt. % nickel, 3-6 wt. % gadolinium, 3-6 wt. % yttrium, and 0.5-0.8% zirconium were added to the molten magnesium. The dissolution rate in 3% KCl brine solution at 90° C. as 62-80 mg/cm.sup.2-hr.

Example 8

[0113] An AZ91D magnesium alloy having 9 wt. % aluminum, 1 wt. % zinc and 90 wt. % magnesium. About 16 wt. % of 75 um iron particles were added to the melt and dispersed. The melt was cast into a steel mold. The iron particles did not fully melt during the mixing and casting processes. The degradable metal dissolved and/or degraded at a rate of about 2.5 mg/cm.sup.2-min in a 3% KCl solution at 20° C. The material dissolved and/or degraded at a rate of 60 mg/cm.sup.2-hr in a 3% KCl solution at 65° C. The material dissolved and/or degraded at a rate of 325 mg/cm.sup.2-hr. in a 3% KCl solution at 90° C. The dissolving and/or degrading rate of the degradable metal for each these test was generally constant. The iron particles were less than 1 μm, but were not nanoparticles. However, the iron particles could be nanoparticles, and such addition would change the dissolving and/or degrading rate of the degradable metal.

Example 9

[0114] An AZ91D magnesium alloy having 9 wt. % aluminum, 1 wt. % zinc and 90 wt. % magnesium was melted to above 700° C. About 2 wt. % 75 um iron particles were added to the melt and dispersed. The iron particles did not fully melt during the mixing and casting processes. The material dissolved and/or degraded at a rate of 0.2 mg/cm.sup.2-min in a 3% KCl solution at 20° C. The material dissolved and/or degraded at a rate of 1 mg/cm.sup.2-hr in a 3% KCl solution at 65° C. The material dissolved and/or degraded at a rate of 10 mg/cm.sup.2-hr in a 3% KCl solution at 90° C. The dissolving and/or degrading rate of the degradable metal for each these test was generally constant. The iron particles were less than 1 μm, but were not nanoparticles. However, the iron particles could be nanoparticles, and such addition would change the dissolving and/or degrading rate of the degradable metal.

Example 10

[0115] An AZ91D magnesium alloy having 9 wt. % aluminum, 1 wt. % zinc and 90 wt. % magnesium was melted to above 700° C. About 2 wt. % nano iron particles and about 2 wt. % nano graphite particles were added to the composite using ultrasonic mixing. The melt was cast into steel molds. The iron particles and graphite particles did not fully melt during the mixing and casting processes. The material dissolved and/or degraded at a rate of 2 mg/cm.sup.2-min in a 3% KCl solution at 20° C. The material dissolved and/or degraded at a rate of 20 mg/cm.sup.2-hr in a 3% KCl solution at 65° C. The material dissolved and/or degraded at a rate of 100 mg/cm.sup.2-hr in a 3% KCl solution at 90° C. The dissolving and/or degrading rate of the degradable metal for each these test was generally constant.

[0116] The dissolvable or degradable metal generally includes a base metal or base metal alloy having discrete particles disbursed in the base metal or base metal alloy. The discrete particles are generally uniformly dispersed through the base metal or base metal alloy using techniques such as, but not limited to, thixomolding, stir casting, mechanical agitation, electrowetting, ultrasonic dispersion and/or combinations of these methods; however, this is not required. The degradable metal can be designed to corrode at the grains in the degradable metal, at the grain boundaries of the degradable metal, and/or the location of the particle additions in the degradable metal. The particle size, particle morphology and particle porosity of the particles can be used to affect the rate of corrosion of the degradable metal. The particles can optionally have a surface area of 0.001 m.sup.2/g-200 m.sup.2/g (and all values and ranges therebetween). The base metal of the degradable metal can include magnesium, zinc, titanium, aluminum, iron, or any combination or alloys thereof. The particles can include, but is not limited to, beryllium, magnesium, aluminum, zinc, cadmium, iron, tin, copper, titanium, lead, nickel, carbon, calcium, boron carbide, and any combinations and/or alloys thereof. In one non-limiting specific embodiment, the degradable metal includes a magnesium and/or magnesium alloy as the base metal or base metal alloy, and nanoparticle additions. In another non-limiting specific embodiment, the degradable metal includes aluminum and/or aluminum alloy as the base metal or base metal alloy, and nanoparticle additions. The particles in the degradable metal are generally less than about 1 μm in size (e.g., 0.00001-0.999 μm and all values and ranges therebetween), typically less than about 0.5 μm, more typically less than about 0.1 μm, and typically less than about 0.05 μm, still more typically less than 0.005 μm, and yet still more typically no greater than 0.001 μm (nanoparticle size). The total content of the particles in the degradable metal is generally about 0.01-70 wt. % (and all values and ranges therebetween), typically about 0.05-49.99 wt. %, more typically about 0.1-40 wt. %, still more typically about 0.1-30 wt. %, and even more typically about 0.5-20 wt. %. When more than one type of particle is added in the degradable metal, the content of the different types of particles can be the same or different. When more than one type of particle is added in the degradable metal, the shape of the different types of particles can be the same or different. When more than one type of particle is added in the degradable metal, the size of the different types of particles can be the same or different. After the mixing process is completed, the molten magnesium or magnesium alloy and the particles that are mixed in the molten magnesium or magnesium alloy are cooled to form a solid component. Such a formation in the melt is called in situ particle formation as illustrated in FIGS. 19-21. Such a process can be used to achieve a specific galvanic corrosion rate in the entire magnesium composite and/or along the grain boundaries of the magnesium composite. The final magnesium composite can also be enhanced by heat treatment as well as deformation processing (such as extrusion, forging, or rolling) to further improve the strength of the final composite over the as-cast material; however, this is not required. The deformation processing can be used to achieve strengthening of the magnesium composite by reducing the grain size of the magnesium composite. Achievement of in situ particle size control can be achieved by mechanical agitation of the melt, ultrasonic processing of the melt, controlling cooling rates, and/or by performing heat treatments. In situ particle size can also or alternatively be modified by secondary processing such as rolling, forging, extrusion and/or other deformation techniques. A smaller particle size can be used to increase the dissolution rate of the magnesium composite. An increase in the weight percent of the in situ formed particles or phases in the magnesium composite can also or alternatively be used to increase the dissolution rate of the magnesium composite. A phase diagram for forming in situ formed particles or phases in the magnesium composite is illustrated in FIG. 22.

[0117] The degradable metal can be designed to corrode at the grains in the degradable metal, at the grain boundaries of the degradable metal, and/or the location of the particle additions in the degradable metal e depending on selecting where the particle additions fall on the galvanic chart. For example, if it is desired to promote galvanic corrosion only along the grain boundaries (500) of the grains (510) as illustrated in FIGS. 16-18, a degradable metal can be selected such that one galvanic potential exists in the base metal or base metal alloy where its major grain boundary alloy composition (530) will be more anodic as compared to the matrix grains (i.e., grains that form in the base metal or base metal alloy) located in the major grain boundary, and then a particle addition (520) will be selected which is more cathodic as compared to the major grain boundary alloy composition. This combination will cause corrosion of the material along the grain boundaries, thereby removing the more anodic major grain boundary alloy (530) at a rate proportional to the exposed surface area of the cathodic particle additions (520) to the anodic major grain boundary alloy (530).

[0118] If a slower corrosion rate of the degradable metal is desired, two or more particle additions can be added to the degradable metal to be deposited at the grain boundary as illustrated in FIG. 18. If the second particle (540) is selected to be the most anodic in the degradable metal, the second particle will first be corroded, thereby generally protecting the remaining components of the degradable metal based on the exposed surface area and galvanic potential difference between second particle and the surface area and galvanic potential of the most cathodic system component. When the exposed surface area of the second particle (540) is removed from the system, the system reverts to the two previous embodiments described above until more particles of second particle (540) are exposed. This arrangement creates a mechanism to retard corrosion rate with minor additions of the second particle component.

[0119] It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained, and since certain changes may be made in the constructions set forth without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. The invention has been described with reference to preferred and alternate embodiments. Modifications and alterations will become apparent to those skilled in the art upon reading and understanding the detailed discussion of the invention provided herein. This invention is intended to include all such modifications and alterations insofar as they come within the scope of the present invention. It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention, which, as a matter of language, might be said to fall there between. The invention has been described with reference to the preferred embodiments. These and other modifications of the preferred embodiments as well as other embodiments of the invention will be obvious from the disclosure herein, whereby the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation. It is intended to include all such modifications and alterations insofar as they come within the scope of the appended claims.