SOLID-STATE COOLING OF DRILLING FLUID ON A RIG

Abstract

A system for cooling drilling fluid on a drilling rig includes a heat exchanger and a solid-state chiller including at least one of a magnetocaloric chiller, an electrocaloric chiller, and an elastocaloric chiller. A first pump is configured to circulate drilling fluid through the heat exchanger and a second pump is configured to circulate a coolant through the solid-state chiller and the heat exchanger. The solid-state chiller is configured to cool the coolant circulating therethrough and thereby cool drilling fluid circulating through the heat exchanger.

Claims

1. A system for cooling drilling fluid on a drilling rig, the system comprising: a heat exchanger; a solid-state chiller including at least one of a magnetocaloric chiller, an electrocaloric chiller, and an elastocaloric chiller; a first pump configured to circulate drilling fluid through the heat exchanger; a second pump configured to circulate a coolant through the solid-state chiller and the heat exchanger; and wherein the solid-state chiller is configured to cool the coolant circulating therethrough and thereby cool drilling fluid circulating through the heat exchanger.

2. The system of claim 1, further comprising a filter in fluid communication with the first pump and the heat exchanger.

3. The system of claim 1, wherein the solid-state chiller comprises a magnetocaloric chiller comprising: a magnetocaloric material; a magnetic field source configured to apply and remove a magnetic field to and from the magnetocaloric material; a heat sink configured to remove heat from the magnetocaloric material when the magnetic field source applies or removes the magnetic field; and a heat source configured to provide heat to the magnetocaloric material when the magnetic field source applies or removes the magnetic field, the heat source including the coolant.

4. The system of claim 3, wherein the magnetocaloric material is deployed on a rotatable platform configured to rotate the magnetocaloric material into and out of the magnetic field generated by the magnetic field source.

5. The system of claim 3, wherein the magnetic field source comprises an electromagnet.

6. The system of claim 3, wherein the magnetocaloric material comprises a lanthanide, a lanthanide alloy, a manganese alloy, an iron alloy, or a nickel alloy.

7. The system of claim 1, wherein the solid-state chiller comprises an electrocaloric chiller comprising: an electrocaloric material; an electric field source configured to apply and remove an electric field to and from the electrocaloric material; a heat sink configured to remove heat from the electrocaloric material when the electric field source applies or removes the electric field; and a heat source configured to provide heat to the electrocaloric material when the electric field source applies or removes the electric field, the heat source including the coolant.

8. The system of claim 7, wherein: the electrocaloric material is deployed in a fluid flow loop; the flow loop is configured to flow from the electrocaloric material to the heat sink when the electric field is applied to the electrocaloric material; and the flow loop is configured to flow from the electrocaloric material to the heat source when the electric field is removed from the electrocaloric material.

9. The system of claim 7, wherein the electrocaloric material comprises a lead-based ceramic capacitor or a piezoelectric enhanced copolymer or terpolymer film.

10. The system of claim 1, wherein the solid-state chiller comprises an elastocaloric chiller comprising: an elastocaloric material; an actuator configured to apply and remove a stress to and from the elastocaloric material; a heat sink configured to remove heat from the elastocaloric material when the actuator applies or removes the stress; and a heat source configured to provide heat to the elastocaloric material when the actuator applies or removes the stress, the heat source including the coolant.

11. The system of claim 10, wherein: the elastocaloric material is deployed in a fluid flow loop; the flow loop is configured to flow from the elastocaloric material to the heat sink when the stress is applied to the elastocaloric material; and the flow loop is configured to flow from the elastocaloric material to the heat source when the stress is removed from the elastocaloric material.

12. The system of claim 10, wherein the elastocaloric material comprises a nickel titanium or a copper aluminum nickel shape memory alloy.

13. The system of claim 1, further including a vapor compression chiller in series with the solid-state chiller such that the second pump circulates the coolant through the vapor compression chiller, the solid-state chiller, and the heat exchanger.

14. The system of claim 1, further comprising first and second of the solid-state chillers coupled in series such that the second pump circulates the coolant through the first solid-state chiller, the second solid-state chiller, and the heat exchanger, the first solid-state chiller comprising one of the magnetocaloric chiller, the electrocaloric chiller, and the elastocaloric chiller, the second solid-state chiller comprising a different one of the magnetocaloric chiller, the electrocaloric chiller, and the elastocaloric chiller.

15. A method for cooling drilling fluid on a drilling rig, the method comprising: circulating drilling fluid through a heat exchanger on a drilling rig; circulating a coolant through the heat exchanger and a solid-state chiller, the solid-state chiller including a magnetocaloric chiller, an electrocaloric chiller, or an elastocaloric chiller; and applying and removing a magnetic field, an electric field, or a stress to and from a corresponding magnetocaloric material, an electrocaloric material, or an elastocaloric material to remove heat from the coolant and thereby cool the circulating drilling fluid.

16. The method of claim 15, wherein the applying and removing further comprises: applying the magnetic field, the electric field, or the stress to the corresponding magnetocaloric material, the electrocaloric material, or the elastocaloric material to generate heat; dissipating the heat to a heat sink while applying the magnetic field, the electric field, or the stress; removing the magnetic field, the electric field, or the stress after dissipating the heat to cool the corresponding magnetocaloric material, the electrocaloric material, or the elastocaloric material; and removing heat from the coolant in the heat source with the cooled magnetocaloric material, the electrocaloric material, or the elastocaloric material to thereby cool the circulating drilling fluid.

17. The method of claim 16, wherein the solid-state chiller comprises a magnetocaloric chiller; the applying the magnetic field comprises rotating the magnetocaloric material into the magnetic field; and the removing the magnetic field comprises rotating the magnetocaloric material away from the magnetic field.

18. The method of claim 16, wherein the solid-state chiller comprises a magnetocaloric chiller; the applying the magnetic field comprises providing electrical power to an electromagnet; and the removing the magnetic field comprises removing electrical power from the electromagnet.

19. The method of claim 16, wherein the solid-state chiller comprises an electrocaloric chiller; the electrocaloric material is deployed in a fluid flow loop; the dissipating the heat comprises flowing a fluid through the flow loop from the electrocaloric material to the heat sink; and the removing the heat from the coolant comprising flowing the fluid through the flow loop from the electrocaloric material to the heat source.

20. The method of claim 16, wherein the solid-state chiller comprises an elastocaloric chiller; the elastocaloric material is deployed in a fluid flow loop; the dissipating the heat comprises flowing a fluid through the flow loop from the elastocaloric material to the heat sink; and the removing the heat from the coolant comprising flowing the fluid through the flow loop from the elastocaloric material to the heat source.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] For a more complete understanding of the disclosed subject matter, and advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

[0008] FIG. 1 depicts an example drilling rig including a disclosed drilling fluid cooling system having a solid-state chiller.

[0009] FIG. 2 depicts one example embodiment of the cooling system shown on FIG. 1.

[0010] FIGS. 3A and 3B (collectively FIG. 3) depict example thermodynamic cycles for magnetocaloric, electrocaloric, and elastocaloric chiller embodiments (3A) and inverse magnetocaloric, inverse electrocaloric, and inverse elastocaloric chiller embodiments (3B).

[0011] FIGS. 4A and 4B (collectively FIG. 4) depict alternative embodiments of example cooling systems configured for cooling drilling fluid in use on a drilling rig.

[0012] FIG. 5 schematically depicts an example embodiment of a magnetocaloric chiller.

[0013] FIG. 6 schematically depicts an example embodiment of an electrocaloric chiller.

[0014] FIGS. 7A and 7B (collectively FIG. 7) schematically depict example embodiments of an elastocaloric chiller.

[0015] FIGS. 8A and 8B depict flow charts of example methods for cooling drilling fluid in use on a drilling rig.

DETAILED DESCRIPTION

[0016] In one example embodiment, a system for cooling drilling fluid on a drilling rig includes a heat exchanger and a solid-state chiller including at least one of a magnetocaloric chiller, an electrocaloric chiller, and an elastocaloric chiller. A first pump is configured to circulate drilling fluid through the heat exchanger and a second pump is configured to circulate a coolant through the solid-state chiller and the heat exchanger. The solid-state chiller is configured to cool the coolant circulating therethrough and thereby cool drilling fluid circulating through the heat exchanger.

[0017] A disclosed method for cooling drilling fluid on a drilling rig includes circulating drilling fluid through a heat exchanger on a drilling rig and circulating a coolant through the heat exchanger and a solid-state chiller, the solid-state chiller including a magnetocaloric chiller, an electrocaloric chiller, or an elastocaloric chiller. A magnetic field, an electric field, or a stress is applied to and removed from a corresponding magnetocaloric material, an electrocaloric material, or an elastocaloric material to remove heat from the coolant and thereby cool the circulating drilling fluid.

[0018] FIG. 1 depicts an example drilling rig 20 including a disclosed drilling fluid cooling system 100 having a solid-state chiller. The drilling rig 20 may be positioned over a subterranean formation (not shown). The rig 20 may include, for example, a derrick and a hoisting apparatus (also not shown) for raising and lowering a drill string 30, which, as shown, extends into wellbore 40 and includes drill bit 32. The drill string 30 may include various other tools, for example, including a downhole drilling motor, a steering tool such as a rotary steerable (RSS) tool or a bent sub, and one or more MWD and/or LWD tools including various sensors for sensing downhole characteristics of the wellbore and the surrounding formation (none of which are shown for simplicity of depiction). The disclosed embodiments are not limited with regards to these other tools in the drill string.

[0019] Drilling rig 20 further includes a surface system 50 for controlling the flow of drilling fluid used on the rig (e.g., used in drilling the wellbore 40). In the example rig 20 depicted, drilling fluid 35 is pumped downhole (as depicted at 62), for example, via a conventional mud pump 57. The drilling fluid 35 may be pumped, for example, through a standpipe 58 and mud hose 59 in route to the drill string 30. The drilling fluid 35 typically emerges from the drill string 30 at or near the drill bit 32 and creates an upward flow 64 of mud through the wellbore annulus 42 (the annular space between the drill string and the wellbore wall). The drilling fluid 35 then flows through a return conduit 52 and solids control equipment 55 to a mud pit system 56 where it may be recirculated. It will be appreciated that the terms drilling fluid and mud are used synonymously herein.

[0020] It will be further appreciated that the drilling fluid returning to the surface (in flow 64) is sometimes much warmer (e.g., up to and exceeding 10 degrees C. warmer) than the fluid pumped downhole (in flow 62). The surface system 50 therefore further includes a cooling system 100 including a solid-state chiller. In the depicted example embodiment, the system 100 may receive or draw warm drilling fluid from mud pit 56 via conduit 102 and return chilled (cooled) drilling fluid to the mud pit via conduit 104. As described in more detail below the system 100 may include a magnetocaloric, an electrocaloric, and/or an elastocaloric (also referred to as a mechanocaloric) cooling chiller.

[0021] FIG. 2 depicts one example embodiment of the cooling system 100 shown on FIG. 1. In the depicted example embodiment, cooling system 100 includes a heat exchanger 110 configured to cool the drilling fluid. A pump 120 circulates drilling fluid from the mud tank system 56 through the heat exchanger 110 via conduits 102 and 104 as depicted. The drilling fluid may optionally be pumped through a filter 125 (or screen) to remove fine solids in route to the heat exchanger 110. A solid-state chiller (also referred to as a solid-state refrigeration unit) 150 is configured to chill or cool a coolant fluid. The chilled coolant fluid may be circulated (e.g., via pump 130) through the heat exchanger 110 via conduits 132 and 134 and thereby cool (remove heat from) the circulating drilling fluid. In operation, pumps 120 and 130 circulate drilling fluid and coolant through the heat exchanger 110. The coolant extracts heat from the drilling fluid, which is in turn extracted from the coolant in the solid-state chiller 150. In this way, the drilling fluid returning to the mud pits in conduits 104 may be cooler (e.g., 5 degrees C., 10 degrees C., or even 15 degrees C. or more cooler) than the drilling fluid in conduit 102.

[0022] With continued reference to FIG. 2, solid-state chiller 150 may include a magnetocaloric, an electrocaloric, and/or an elastocaloric chiller. As used herein the term magnetocaloric chiller refers to a chiller that makes use of the magnetocaloric effect or the inverse magnetocaloric effect, which are magneto-thermodynamic phenomena in which a temperature change is induced when a magnetocaloric material is exposed to a changing magnetic field. In the magnetocaloric effect, an applied magnetic field induces a temperature increase in the magnetocaloric material and removal of the field induces a corresponding temperature decrease. In the inverse magnetocaloric effect, an applied magnetic field induces a temperature decrease in the magnetocaloric material and removal of the field induces a corresponding temperature increase.

[0023] A suitable magnetocaloric chiller may radiate heat to a heat sink when the magnetocaloric material is in the magnetized hot state and may then chill a coolant when the magnetic field is removed (or when the magnetocaloric material is removed from the magnetic field). A suitable inverse magnetocaloric chiller may chill a coolant when the magnetocaloric material is in the magnetized cold state and may then radiate heat to a heat sink when the magnetic field is removed (or when the magnetocaloric material is removed from the magnetic field).

[0024] As used herein the term electrocaloric chiller refers to a chiller that makes use of the electrocaloric effect or the inverse electrocaloric effect, which are phenomena in which a temperature change is induced when an electrocaloric material is exposed to a changing electric field. In the electrocaloric effect, an applied electric field induces a temperature increase in the electrocaloric material and removal of the field induces a corresponding temperature decrease. In the inverse electrocaloric effect, an applied electric field induces a temperature decrease in the electrocaloric material and removal of the field induces a corresponding temperature increase.

[0025] A suitable electrocaloric chiller may radiate heat to a heat sink when the electrocaloric material is in the hot state owing to the application of an external electric field and may then chill a coolant when the electric field is removed. A suitable inverse electrocaloric chiller may chill a coolant when the electrocaloric material is in the cold state owing to the application of an external electric field and may then radiate heat to a heat sink when the electric field is removed.

[0026] As used herein the term elastocaloric chiller refers to a chiller that makes use of the elastocaloric effect or the inverse elastocaloric effect, which are phenomena in which a temperature change is induced when an elastocaloric material (such as a super elastic material or a shape memory material) is exposed to a changing mechanical stress (or stress field). In the elastocaloric effect, an applied stress induces a temperature increase in the elastocaloric material and removal of the stress induces a corresponding temperature decrease. For example, a super elastic material may undergo an exothermic phase transformation from an austenitic phase to a martensitic phase when an external stress is applied, thereby heating the material. The process is reversible such that removing the stress restores the material to the austenitic phase and cools the material. In the inverse elastocaloric effect, an applied stress induces a temperature decrease in the elastocaloric material and removal of the stress induces a corresponding temperature increase.

[0027] A suitable elastocaloric chiller may radiate heat to a heat sink when the elastocaloric material is in the hot state caused by an externally applied stress (e.g., a compressive stress) and may then chill a coolant when the applied stress is removed. A suitable inverse elastocaloric chiller may chill a coolant when the elastocaloric material is in the cold state caused by an externally applied stress (e.g., a compressive stress) and may then radiate heat to a heat sink when the applied stress is removed.

[0028] Turning now to FIGS. 3A and 3B (collectively FIG. 3), schematics of thermodynamic cycles 160 and 180 for example embodiments of solid-state chiller 150 are depicted for magnetocaloric, electrocaloric, and elastocaloric chiller embodiments (FIG. 3A) and inverse magnetocaloric, inverse electrocaloric, and inverse elastocaloric chiller embodiments (FIG. 3B). In FIG. 3A, a magnetic field 162, electric field 164, or mechanical stress 166 may be applied to the corresponding magnetocaloric 163, electrocaloric 165, or elastocaloric 167 materials thereby generating heat 168 (e.g., increasing the temperature of the magnetocaloric, electrocaloric, or elastocaloric material to T+T). The heated solid-state material may be thermally coupled to a heat sink 170 (e.g., a heat exchanger) such that the generated heat is radiated 169 to the heat sink 170 while the magnetic field 162, electric field 164, or mechanical stress 166 remains applied. After some time (e.g., after the generated heat has been expelled to the heat sink and the temperature of the solid-state material has returned to the starting temperature T at 171), the applied magnetic field, electric field, or mechanical stress may be removed (or turned off) at 172, 174, or 176. The temperature of the corresponding magnetocaloric 163, electrocaloric 165, or elastocaloric 167 material is thereby lowered 178 (e.g., to TT) as heat is removed from the solid-state material. The cooled solid-state material may be thermally coupled with a heat source 175 (e.g., another heat exchanger) such that heat may be removed 177 (radiated away) from the heat source (e.g., returning the temperature of the solid-state material to T at 179). In this way a coolant fluid circulating through the heat source (or heat exchanger) may be cooled (or chilled) as described above with respect to FIG. 2. The cycle may be repeated by again applying and removing the magnetic field, electric field, or mechanical stress as described above.

[0029] In FIG. 3B, a magnetic field 182, electric field 184, or mechanical stress 186 may be applied to the corresponding magnetocaloric 183, electrocaloric 185, or elastocaloric 187 material thereby removing heat 188 from the material (e.g., decreasing the temperature of the magnetocaloric, electrocaloric, or elastocaloric material to TT). The cooled solid-state material may be thermally coupled to a heat source (e.g., a heat exchanger) such that heat is radiated 189 from the heat source 190 to the chilled solid-state material 183, 185, 187 while the magnetic field 182, electric field 184, or mechanical stress 186 remains applied. In this way a coolant fluid circulating through the heat source 190 (or heat exchanger) may be cooled (or chilled) as described above with respect to FIG. 2. After some time (e.g., after the temperature of the solid-state material has returned to the starting temperature T at 191), the applied magnetic field, electric field, or mechanical stress may be removed (or turned off) at 192, 194, or 196. The temperature of the corresponding magnetocaloric 183, electrocaloric 185, or elastocaloric 187 material is thereby increased (e.g., to T+T) 198 with the generated heat being radiated 197 to a heat sink 195 (e.g., returning the temperature of the solid-state material to T at 199). The cycle may be repeated by again applying and removing the magnetic field, electric field, or mechanical stress as described above.

[0030] FIGS. 4A and 4B (collectively FIG. 4) depict alternative embodiments of cooling systems 200 and 300 configured for cooling drilling fluid in use on a drilling rig (e.g., while drilling a subterranean wellbore). In FIG. 4A, a heat exchanger 210 is in fluid communication with first and second chillers 250 and 255 that are coupled in series. As described above, a first pump (not shown) may circulate drilling fluid from a mud tank system through the heat exchanger 110. Another pump 220 may circulate coolant fluid through the heat exchanger 210 and the first and second chillers 250 and 255. As described above, the chillers 250, 255 are configured to remove heat from the coolant which in turn removes heat from the drilling fluid in the heat exchanger.

[0031] With continued reference to FIG. 4A, one of the first and second chillers 250, 255 is a conventional vapor compression chiller that makes use of a liquid-gas phase transition to provide cooling (such as a conventional refrigeration unit). For example, the first chiller 250 may be a conventional vapor compression chiller and the second chiller 255 may be a solid-state chiller, such as a magnetocaloric, electrocaloric, or elastocaloric chiller. Alternatively, the first chiller 250 may be a solid-state chiller and the second chiller 255 may be a conventional vapor compression chiller. In such embodiments, the solid-state chiller may supplement the vapor compression chiller and provide additional cooling power. Such embodiments may advantageously enable additional cooling power without the significant expense of using a more powerful or larger vapor compression chiller.

[0032] In FIG. 4B, system 300 is similar to system 200 in that heat exchanger 310 is in fluid communication with first and second chillers 350 and 355 that are also coupled in series. However, in system 300, first chiller 350 is a first solid-state chiller and second chiller 355 is a second solid-state chiller. In example embodiments, the first and second solid-state chillers 350, 355 may include the same type of chiller (e.g., a magnetocaloric, electrocaloric, or elastocaloric chiller). Such embodiments may advantageously enable smaller scale chillers to be employed and may potentially reduce costs. In other embodiments, the first and second solid-state chillers 350, 355 may include different types of chillers (e.g., magnetocaloric and electrocaloric chillers, magnetocaloric and elastocaloric chillers, or electrocaloric and elastocaloric chillers). Such embodiments may advantageously enable each of the chillers to be configured to operate in a preferred temperature range and may potentially improve operational efficiency and reduce costs.

[0033] With continued reference to FIG. 4, it will be appreciated that systems 200 and 300 are not limited to the use of first and second chillers. In some embodiments the systems 200, 300 may include first, second, and third chillers coupled in series or even first, second, third, and fourth chillers coupled in series. Such embodiments may be configured to improve operational efficiency, for example, by enabling lower power chillers to be employed or by ensuring that each chiller operates in a preferred temperature range.

[0034] FIGS. 5, 6, and 7 schematically depict example embodiments of a magnetocaloric chiller 450 (FIG. 5), an electrocaloric chiller 550 (FIG. 6), and an elastocaloric chiller 650 (FIG. 7). While these example chiller embodiments are described in detail with respect to magnetocaloric chiller, electrocaloric chiller, and elastocaloric chiller embodiments, those of ordinary skill in the art will readily appreciate that they may be readily reconfigured for use in inverse magnetocaloric chiller, inverse electrocaloric chiller, and inverse elastocaloric chiller embodiments (e.g., by swapping the heat sink and heat source and replacing the solid-state materials with inverse materials). It will be further appreciated that certain example embodiments may make use of both caloric and inverse caloric materials to achieve a larger temperature span during cycling (e.g., the cycles described above with respect to FIG. 3).

[0035] In FIG. 5, magnetocaloric chiller 450 includes a magnetic field source 455 (such as a permanent magnet or an electromagnet), a magnetocaloric material 460 and first and second heat exchangers 465, 470 (e.g., a heat sink 465 and a heat source 470). In the depicted example embodiment, the magnetocaloric material 460 may be deployed on a rotatable platform 480 such that it may be rotated into and out of the magnetic field. Rotation of the platform 480 to a first rotational position rotates the magnetocaloric material 460 into the magnetic field generated by the magnetic field source 455, thereby generating heat in the magnetocaloric material 460 (e.g., as described above with respect to FIG. 3A). The generated heat may be radiated to an adjacent (or nearby) heat sink 465. Rotation of the platform 480 to a second rotational position rotates the magnetocaloric material 460 out of (or away from) the magnetic field generated by the magnetic field source 455, thereby reducing the temperature of the magnetocaloric material 460 (e.g., as also described above with respect to FIG. 3A). The magnetocaloric material may then absorb heat from the heat source (the second heat exchanger) and thereby chill a coolant that may be used to further chill the drilling fluid as described above.

[0036] It will be appreciated that the disclosed embodiments are not limited to embodiments including a single magnetocaloric material element. The disclosed embodiments may include multiple (e.g. first and second as depicted) magnetocaloric material elements deployed about the periphery of the platform 480. It will be further appreciated that the disclosed embodiments are not limited to embodiments in which the magnetocaloric material 460 is deployed on a rotating platform. In alternative embodiments, the platform may translate between the first and second positions (into and out of the magnetic field). In still other alternative embodiments, the platform may be stationary and the magnetic field source 455 may include an electromagnetic source that may be repeatedly turned on and off to generate the thermodynamic cycle (to warm and cool the magnetocaloric material 460) or the chiller may further include variable shielding (magnetic shields that are configured to move into and out of the magnetic field or that are configured to be actuated and deactuated) that distort the flux emanating from a permanent magnet.

[0037] With continued reference to FIG. 5, the magnetocaloric material 460 may include substantially any suitable magnetocaloric material. In example embodiments, the magnetocaloric material 460 may include lanthanides or lanthanide alloys such as gadolinium, holmium, Gd.sub.5(Si, Ge).sub.4, or yttrium doped gadolinium (e.g., Gd.sub.98.7Y.sub.1.3 or Gd.sub.96.6Y.sub.3.4). Lanthanum containing alloys may include, for example, La.sub.0.7Ca.sub.0.3MnO.sub.3, La(Fe,Mn,Si)13, LaFe.sub.11.6Si.sub.1.4, LaFe.sub.11.2Si.sub.1.8, LaFe10.sub..7Co.sub.1.3Si, LaFe.sub.11.05Co.sub.0.91Si.sub.1.04, LaFe.sub.11.40Co.sub.0.52Si.sub.1.09, LaFe.sub.11.74Co.sub.0.13Si.sub.1.13, LaFe.sub.11.84Mn.sub.0.34Si.sub.1.30H.sub.x, and LaFe.sub.11.83Mn.sub.0.32Si.sub.1.30H.sub.x. The magnetocaloric material 460 may further include manganese, iron, or nickel-based alloys, for example, including MnFeP.sub.0.55As.sub.0.45, MnFe.sub.0.95P.sub.0.585Si.sub.0.34B.sub.0.075, Mn.sub.3GaC, Fe.sub.49Rh.sub.51Ni.sub.50.2Mn.sub.35.0In.sub.14.8, Ni.sub.49.6MB.sub.35.6In.sub.14.8, Ni.sub.49.8Mn.sub.35.0In.sub.15.2, Ni.sub.45.7Mn.sub.36.6In.sub.13.5Co.sub.4.2, (MnNiSi).sub.1-x(FeCoGa).sub.x. In example embodiments that make use of the inverse magnetocaloric effect, the magnetocaloric material may include, for example, a NiMnSn alloy.

[0038] FIG. 6 schematically depicts an example electrocaloric chiller 550. In the depicted example embodiment, an electrocaloric material 560 may be deployed in a fluid flow loop 580. The electrocaloric material 560 is electrically connected with an electric field source 555 (e.g., a power source) and a corresponding switch 557 that enables the field to be turned on and off. The flow loop 580 may include first and second heat exchangers 565, 570 (e.g., a heat sink 565 and a heat source 570) and a pump 575 configured to provide reversible flow in the loop 580. The heat source 570 may be thermally coupled with the coolant used cool the drilling fluid (e.g., in heat exchanger 110 as described above with respect to FIG. 2)

[0039] In operation, the switch 557 is closed while fluid is pumped clockwise 582 around the loop 580. Closing the switch 557 applies an electric field to the electrocaloric material 560 thereby generating heat in the electrocaloric material 560 (e.g., as described above with respect to FIG. 3A). The generated heat is transferred to the circulating fluid and dissipated in the first heat exchanger 565 (the heat sink). The switch 557 is then open and the fluid flow reversed (to a counterclockwise direction 584 in the loop 580). Opening the switch 557 removes the electric field thereby lowering the temperature of (removing heat from) the electrocaloric material 560 (e.g., as also described above with respect to FIG. 3A). Heat is therefore removed from the circulating fluid and from the coolant flowing through the second heat exchanger 570 (the heat source). In this way, the electrocaloric chiller 550 cools (chills) the coolant which in turn chills the drilling fluid as described above with respect to FIG. 2.

[0040] With continued reference to FIG. 6, the electrocaloric material 560 may include substantially any suitable electrocaloric material. In example embodiments, the electrocaloric material 560 may include a lead-based ceramic such as a PbSc.sub.0.5Ta.sub.0.5O.sub.3 (PST) multilayer capacitor. In other example embodiments, the electrocaloric material 560 may include piezoelectric enhanced copolymer or terpolymer films such as poly(vinylidene fluoride-co-trifluoroethylene) PVDF-TrFE) and poly(vinylidene fluoride-co-trifluoroethylene-chlorofluoroethylene) P(VDF-TrFE-CFE), as well as polymer composites including P(VDF-TrFE) and/or P(VDF-TrFE-CFE). In other example embodiments, the electrocaloric material 460 may include a ceramic material such as PbZrO.sub.3, NaBiTiO.sub.3BaTiO.sub.3, Hf.sub.0.5Zr.sub.0.5O.sub.2, and/or PbZr.sub.0.53 Ti.sub.0.47O.sub.3/CoFe.sub.2O.sub.4. In example embodiments that make use of the inverse electrocaloric effect, the electrocaloric material may include, for example, a lead-based ceramic such as PbMg.sub.0.5W.sub.0.5O.sub.3 (e.g., a multi-layer capacitor).

[0041] FIGS. 7A and 7B (collectively FIG. 7) schematically depict example elastocaloric chiller embodiments 650 and 650. In the example embodiment depicted in FIG. 7A, an elastocaloric material 660 is deployed in first and second fluid flow loops 680, 685. The elastocaloric material 660 is mechanically coupled with an actuator 655 (e.g., a hydraulic piston) that is configured to apply a stress to the elastocaloric material 660. The first and second fluid flow loops 680, 685 include corresponding first and second heat exchangers 665, 670 (e.g., a heat sink 665 and a heat source 670) and corresponding pumps (not shown). The heat source 670 is thermally coupled with the coolant used to cool the drilling fluid (e.g., in heat exchanger 110 in system 100 as described above with respect to FIG. 2).

[0042] In operation, the actuator 655 applies a stress to the elastocaloric material 660 thereby generating heat (e.g., as described above with respect to FIG. 3A). Fluid is pumped through the first flow loop 680 and the corresponding first heat exchanger 665. The generated heat is transferred to the circulating fluid and dissipated in the first heat exchanger 665 (the heat sink). The actuator then removes the applied stress thereby lowering the temperature of the elastocaloric material 660 (e.g., as also described above with respect to FIG. 3A). Fluid is then pumped through the second flow loop 685 and the corresponding second heat exchanger 670. Heat is therefore removed from the circulating fluid and from the coolant flowing through the second heat exchanger 670 (the heat source). In this way, the electrocaloric chiller 650 cools (chills) the coolant in the second heat exchanger which in turn chills the drilling fluid as described above with respect to FIG. 2.

[0043] In the example embodiment depicted in FIG. 7B, first and second elastocaloric material bundles 660A and 660B are deployed about an actuator 655. The actuator is configured to apply a stress to one of the bundles while leaving the other bundle unstressed. For example, the actuator 655 may apply a stress to the first bundle 660A while leaving the second bundle 660B unstressed. The actuator may then remove the stress from the first bundle 660A while applying a stress to the second bundle 660B. The chiller 650 further includes a plurality of flow loops (shown collectively at 680) that include first and second heat exchangers 665, 670 (e.g., a heat sink 665 and a heat source 670) and corresponding pumps and valves (not shown).

[0044] In operation the actuator 655 applies a stress to the first bundle 660A while removing stress from the second bundle 660B. In this way heat may be generated in the first bundle and removed from the second bundle (thought of another way heat may be generated in the first bundle and cold may be generated in the second bundle). A first flow loop may enable fluid to be pumped through the first bundle and the first heat exchanger (the heat sink). A second flow loop may enable fluid to be simultaneously pumped through the second bundle and the second heat exchanger (thereby cooling the coolant in the heat source). After some time, the actuator may be reversed such that stress is applied to the second bundle 660B and removed from the first bundle 660A (thereby generating heat in the second bundle and removing heat from the first bundle). A third flow loop may enable fluid to be pumped through the second bundle and the first heat exchanger (the heat sink). A fourth flow loop may enable fluid to be simultaneously pumped through the first bundle and the second heat exchanger (thereby cooling the coolant in the heat source). This cycle may be repeated to provide substantially continuous cooling of the coolant and the drilling fluid.

[0045] With continued reference to FIG. 7, the elastocaloric material 660 may include substantially any suitable elastocaloric material. In example embodiments, the elastocaloric material 660 may include a shape memory alloy such as a nickel titanium alloy such as nitinol (Ni.sub.55Ti.sub.45) or a copper aluminum nickel alloy. In example embodiments, the elastocaloric material 660 may include NiTi, TiNiCu, CuAlNi, or CuZnAl alloys, however, the disclosed embodiments are not limited in this regard. In example embodiments that make use of the inverse elastocaloric effect, the elastocaloric material may include, for example, a NiTi alloy.

[0046] Turning now to FIGS. 8A and 8B (collectively FIG. 8), flow charts of example methods 700, 720 for cooling drilling fluid on a drilling rig are depicted. In FIG. 8A, method 700 includes circulating drilling fluid through a heat exchanger in a drilling rig at 702 and circulating a coolant through the heat exchanger and a solid-state chiller at 704. A heat generating field is applied to a solid-state material in solid-state chiller at 706 to generate heat. As described above, application of the heat generating field may include applying a magnetic field to a magnetocaloric material, applying an electric field to an electrocaloric material, or applying a mechanical stress (a stress field) to an elastocaloric material to generate heat in a magnetocaloric, electrocaloric, or elastocaloric material. The generated heat may be dissipated to a heat sink (e.g., a heat exchanger) at 708. The applied heat generating field (the magnetic field, the electric field, or the mechanical stress) may be removed at 710 to cool the solid-state material. Heat may be absorbed from a heat source at 712 (e.g., the coolant circulating in 704) to chill the coolant and the circulating drilling fluid.

[0047] In FIG. 8B, method 720 includes circulating drilling fluid through a heat exchanger in a drilling rig at 722 and circulating a coolant through the heat exchanger and a solid-state chiller at 724. A field is applied to a solid-state material in solid-state chiller at 726 to cool the material. As described above, application of the field may include applying a magnetic field to a magnetocaloric material, applying an electric field to an electrocaloric material, or applying a mechanical stress (a stress field) to an elastocaloric material to cool the magnetocaloric, electrocaloric, or elastocaloric material. Heat may be absorbed from a heat source at 728 (e.g., the coolant circulating in 704) to chill the coolant and the circulating drilling fluid. The applied field (the magnetic field, the electric field, or the mechanical stress) may be removed at 730 to heat the solid-state material. The generated heat may be dissipated to a heat sink (e.g., a heat exchanger) at 732.

[0048] It will be understood that the present disclosure includes numerous embodiments. These embodiments include, but are not limited to, the following embodiments.

[0049] In a first embodiment, a system for cooling drilling fluid on a drilling rig comprises a heat exchanger; a solid-state chiller including at least one of a magnetocaloric chiller, an electrocaloric chiller, and an elastocaloric chiller; a first pump configured to circulate drilling fluid through the heat exchanger; a second pump configured to circulate a coolant through the solid-state chiller and the heat exchanger; and wherein the solid-state chiller is configured to cool the coolant circulating therethrough and thereby cool drilling fluid circulating through the heat exchanger.

[0050] A second embodiment may include the first embodiment, further comprising a filter in fluid communication with the first pump and the heat exchanger.

[0051] A third embodiment may include any one of the first through second embodiments, wherein the solid-state chiller comprises a magnetocaloric chiller comprising a magnetocaloric material; a magnetic field source configured to apply and remove a magnetic field to and from the magnetocaloric material; a heat sink configured to remove heat from the magnetocaloric material when the magnetic field source applies or removes the magnetic field; and a heat source configured to provide heat to the magnetocaloric material when the magnetic field source applies or removes the magnetic field, the heat source including the coolant.

[0052] A fourth embodiment may include the third embodiment, wherein the magnetocaloric material is deployed on a rotatable platform configured to rotate the magnetocaloric material into and out of the magnetic field generated by the magnetic field source.

[0053] A fifth embodiment may include any one of the third through fourth embodiments, wherein the magnetic field source comprises an electromagnet.

[0054] A sixth embodiment may include any one of the third through fifth embodiments, wherein the magnetocaloric material comprises a lanthanide, a lanthanide alloy, a manganese alloy, an iron alloy, or a nickel alloy.

[0055] A seventh embodiment may include any one of the first through sixth embodiments, wherein the solid-state chiller comprises an electrocaloric chiller comprising an electrocaloric material an electric field source configured to apply and remove an electric field to and from the electrocaloric material; a heat sink configured to remove heat from the electrocaloric material when the electric field source applies or removes the electric field; and a heat source configured to provide heat to the electrocaloric material when the electric field source applies or removes the electric field, the heat source including the coolant.

[0056] An eighth embodiment may include the seventh embodiment, wherein the electrocaloric material is deployed in a fluid flow loop; the flow loop is configured to flow from the electrocaloric material to the heat sink when the electric field is applied to the electrocaloric material; and the flow loop is configured to flow from the electrocaloric material to the heat source when the electric field is removed from the electrocaloric material.

[0057] A ninth embodiment may include any one of the seventh through eighth embodiments, wherein the electrocaloric material comprises a lead-based ceramic capacitor or a piezoelectric enhanced copolymer or terpolymer film.

[0058] A tenth embodiment may include any one of the first through ninth embodiments, wherein the solid-state chiller comprises an elastocaloric chiller comprising an elastocaloric material; an actuator configured to apply and remove a stress to and from the elastocaloric material; a heat sink configured to remove heat from the elastocaloric material when the actuator applies or removes the stress; and a heat source configured to provide heat to the elastocaloric material when the actuator applies or removes the stress, the heat source including the coolant.

[0059] An eleventh embodiment may include the tenth embodiment, wherein the elastocaloric material is deployed in a fluid flow loop; the flow loop is configured to flow from the elastocaloric material to the heat sink when the stress is applied to the elastocaloric material; and the flow loop is configured to flow from the elastocaloric material to the heat source when the stress is removed from the elastocaloric material.

[0060] A twelfth embodiment may include any one of the tenth through eleventh embodiments, wherein the elastocaloric material comprises a nickel titanium or a copper aluminum nickel shape memory alloy.

[0061] A thirteenth embodiment may include any one of the first through twelfth embodiments, further including a vapor compression chiller in series with the solid-state chiller such that the second pump circulates the coolant through the vapor compression chiller, the solid-state chiller, and the heat exchanger.

[0062] A fourteenth embodiment may include any one of the first through twelfth embodiments, further comprising first and second of the solid-state chillers coupled in series such that the second pump circulates the coolant through the first solid-state chiller, the second solid-state chiller, and the heat exchanger, the first solid-state chiller comprising one of the magnetocaloric chiller, the electrocaloric chiller, and the elastocaloric chiller, the second solid-state chiller comprising a different one of the magnetocaloric chiller, the electrocaloric chiller, and the elastocaloric chiller.

[0063] In a fifteenth embodiment, a method for cooling drilling fluid on a drilling rig comprises circulating drilling fluid through a heat exchanger on a drilling rig; circulating a coolant through the heat exchanger and a solid-state chiller, the solid-state chiller including a magnetocaloric chiller, an electrocaloric chiller, or an elastocaloric chiller; and applying and removing a magnetic field, an electric field, or a stress to and from a corresponding magnetocaloric material, an electrocaloric material, or an elastocaloric material to remove heat from the coolant and thereby cool the circulating drilling fluid.

[0064] A sixteenth embodiment may include the fifteenth embodiment, wherein the applying and removing further comprises applying the magnetic field, the electric field, or the stress to the corresponding magnetocaloric material, the electrocaloric material, or the elastocaloric material to generate heat; dissipating the heat to a heat sink while applying the magnetic field, the electric field, or the stress; removing the magnetic field, the electric field, or the stress after dissipating the heat to cool the corresponding magnetocaloric material, the electrocaloric material, or the elastocaloric material; and removing heat from the coolant in the heat source with the cooled magnetocaloric material, the electrocaloric material, or the elastocaloric material to thereby cool the circulating drilling fluid.

[0065] A seventeenth embodiment may include any one of the sixteenth through seventeenth embodiments, wherein the solid-state chiller comprises a magnetocaloric chiller; the applying the magnetic field comprises rotating the magnetocaloric material into the magnetic field; and the removing the magnetic field comprises rotating the magnetocaloric material away from the magnetic field.

[0066] An eighteenth embodiment may include the sixteenth embodiment, wherein the solid-state chiller comprises a magnetocaloric chiller; the applying the magnetic field comprises providing electrical power to an electromagnet; and the removing the magnetic field comprises removing electrical power from the electromagnet.

[0067] A nineteenth embodiment may include any one of the sixteenth through eighteenth embodiments, wherein the solid-state chiller comprises an electrocaloric chiller; the electrocaloric material is deployed in a fluid flow loop; the dissipating the heat comprises flowing a fluid through the flow loop from the electrocaloric material to the heat sink; and the removing the heat from the coolant comprising flowing the fluid through the flow loop from the electrocaloric material to the heat source.

[0068] A twentieth embodiment may include any one of the sixteenth through nineteenth embodiments, wherein the solid-state chiller comprises an elastocaloric chiller; the elastocaloric material is deployed in a fluid flow loop; the dissipating the heat comprises flowing a fluid through the flow loop from the elastocaloric material to the heat sink; and the removing the heat from the coolant comprising flowing the fluid through the flow loop from the elastocaloric material to the heat source.

[0069] Although solid-state cooling of drilling fluid and certain advantages thereof have been described in detail, it should be understood that various changes, substitutions and alterations may be made herein without departing from the spirit and scope of the disclosure.