Structure for electronic circuit boards and well intervention tool made therewith

Abstract

A printed circuit board (PCB) assembly has at least one substantially circularly shaped PCB. A heat sink surrounds and is and in contact with substantially an entire perimeter of the at least one PCB. The heat sink comprises at least one mounting feature enabling mounting within a well intervention tool such that a plane of the PCB is perpendicular to a longitudinal axis of the well intervention tool.

Description

STRUCTURE FOR ELECTRONIC CIRCUIT BOARDS AND WELLINTERVENTION TOOL MADE THEREWITHBackground

[0001] This disclosure relates to the field of well intervention tools. More specifically, the disclosure relates to structures for electronic circuit boards for use in such well intervention tools to enable the tools to operate at elevated temperatures for extended periods of time.

[0002] The term “well intervention tools” includes any instrument or device conveyed along the interior of a subsurface well for performing tasks related to, among others and without limitation, drilling, completion, remediation and abandonment of the well. Conveyance may be performed by, for example, deploying the tool at the end of an armored electrical cable, at the end of a coiled tubing, or along a jointed pipe such as drill pipe or completion pipe. In the case of conveyance by coiled tubing or drill pipe, the tool may be deployed in the during active drilling of the well.

[0003] Some well intervention tools comprise electronic circuitry in order to control and / or perform various functions of the tool, and / or to make measurements about the well and the earthen formations adjacent to the well Those skilled in the art are aware that many wells, in particular very deep wells and / or wells used to recover geothermal energy expose the electronic circuits to high temperatures, and in the case of while-drilling tool operations, expose the circuits to high amplitude shock and vibration. Furthermore, while-drilling well intervention tools may be subjected to high temperature and shock for extended periods of time, e.g., several weeks.

[0004] It is known in the art to enclose electronic circuits in well intervention tools within a vacuum-insulated container (e.g., Dewar flask). Electronic circuit boards (“printed circuit boards” - PCBs) used in well intervention tools are typically rectangularly shaped, wherein mounting such circuit boards is principally designed to reduce mechanical resonance at particular frequencies so as to avoid mechanical failure of the PCBs induced by motion of the well intervention tool within a well, particularly in the case of while-drilling well intervention tools. PCB arrangements known in the art, while making use of devices (heat sinks) to facilitate heat transfer away from components on the PCBs, may not be optimized for such heat transfer. Further, PCB structures known in the art may not provide separation between high power consumption devices (e.g., power transistors and related circuit drivers) that generate large amounts of heat and low power consumption devices that do not generate large amounts of heat.

[0005] Accordingly, there is a need for improved printed circuit board structures for use with while-drilling well intervention tools, although the scope of the present disclosure is not limited to PCBs used with such tools.Summary

[0006] One aspect of the present disclosure relates to a printed circuit board assembly for use in a well intervention tool. A printed circuit board (PCB) assembly according to this aspect of the disclosure has at least one substantially circularly shaped PCB. A heat sink surrounds and is and in contact with substantially an entire perimeter of the at least one PCB. The heat sink comprises at least one mounting feature enabling mounting within a well intervention tool such that a plane of the PCB is perpendicular to a longitudinal axis of the well intervention tool.

[0007] A well intervention tool according to another aspect of the present disclosure comprises an elongated housing shaped to traverse a subsurface well. At least one PCB assembly according to the above aspect of the present disclosure is mounted in the housing such that a plane of the included PCB is perpendicular to a longitudinal axis of the housing. Some implementations comprise at least a second PCB assembly mounted adjacent to the at least one PCB assembly such that the plane of its included PCB is perpendicular to the longitudinal axis.

[0008] Some implementations further comprise a heat transfer plate in contact with one side of the at least one PCB, the heat transfer plate being shaped to fit within and make circumferential contact with the heat sink.

[0009] Some implementations further comprise at least a second substantially circularly shaped PCB disposed within and in perimeter contact with the heat sink, the at least a second PCB being axially spaced apart from the at least one PCB.

[0010] In some implementations, the at least one PCB comprises plastic, and the at least a second PCB comprises ceramic, the ceramic PCB having mounted thereon electronic components generating more heat than electronic components mounted on the at least one PCB.

[0011] In some implementations, the at least one PCB is mounted to the heat sink using a visco-elastic material.

[0012] In some implementations, the PCB is mounted to the heat sink using a thermally conductive retainer ring.

[0013] In some implementations, the at least one mounting feature comprises at least one opening formed through the heat sink in a direction substantially perpendicular to a plane of the at least one PCB.

[0014] In some implementations, the heat sink is shaped as an annular ring.

[0015] Other aspects and possible advantages will be apparent from the description and claims that follow.Brief Description of the Drawings

[0016] FIGS. 1 A and IB show an example implementation of a basic printed circuit board (PCB) structure according to the present disclosure.

[0017] FIGS. 2A and 2B show the basic PCB structure of FIGS. 1A and IB in an example implementation wherein the PCB structure is mounted in a heat sink or heat pipe.

[0018] FIGS. 3A through 3E show various views of another example implementation of a PCB stack mounted in a heat sink ring.

[0019] FIGS. 4A and 4B show various views of an example implementation of part of a well intervention tool wherein PCB structures according to the present disclosure aremounted within a pressure housing adapter. Some of the PCBs are disposed in a vacuum insulated container.Detailed Description

[0020] FIGS. 1A and IB show, respectively, at 10, oblique and side views of an example implementation of a printed circuit board (PCB) structure according to the present disclosure. For convenience in the description that follows, the PCB structure, by reason of it comprising at least two, axially spaced apart PCBs oriented transversely to a longitudinal, axis may be referred to as a “PCB stack” and in the various drawing figures is denoted by reference numeral 10. The PCB stack 10 in some implementations may comprise more than two, axially spaced apart PCBs. In the present example implementation, the PCB stack 10 may comprise a ceramic PCB 12, which may be substantially circularly shaped or in the shape of a high order regular or irregular polygon, or some other shape having a perimeter to area relationship roughly the same as a circle. “Other shape” in the present context may mean any perimeter shape having all convex curvature(s) along the perimeter directed away from a center of the PCB and / or all obtuse angles between line segments of the perimeter directed away from the center of the PCB. Circular shape has the property and possible advantage of having the largest ratio of perimeter to surface area of any single, closed perimeter shape. Substantially circular in the present context may mean any or all of the foregoing shapes, whether alone or in combination around the perimeter of any one or more PCBs in a PCB stack.

[0021] Spaced apart in a direction normal to the plane of the ceramic PCB 12 may be a conventional, plastic resin PCB 16 (“plastic PCB”), which may be made from polyimide or other plastic known in the art for use in PCBs. The plastic PCB 16 may also be substantially circularly shaped (as defined herein) for the same reason as the ceramic PCB 12. Each of the PCBs 12, 16 may comprise an aperture or opening within its respective circumference for through passage of connecting wiring 14. In the present example implementation, the ceramic PCB 12 may be used to place high power consumption (and thus high heat generating) electronic components (not shown), for example and without limitation, power transistors, silicon controlled rectifiers (SCRs) and the like. Low powerconsumption electronic components (not shown) such as integrated circuits may be mounted on the plastic PCB 16, although such placement of the various components is not to be construed as a limitation on the scope of the present disclosure.

[0022] FIGS. 2A and 2B show an oblique side view of the PCB stack 10 of FIGS. 1A and IB as it may be mounted within a heat pipe or heat sink 22. The heat pipe or heat sink 22 may be generally circularly or otherwise shaped as explained with reference to FIGS. 1 A and IB, so as to contact the PCBs 12, 16 on substantially all of their respective perimeters. In some implementations, the ceramic PCB 12 may be axially spaced apart from the plastic PCB 16 by a resilient pad 18 such as may be made from silicone rubber or other heat resistant elastomeric material. A viscoelastic damping material 20 may be disposed between one side of the plastic PCB 16 and a shoulder or ledge 22A formed in the inner perimeter of the heat sink 22 to limit axial movement of the PCB stack 10 through or along the heat sink 22 while reducing transmission of axial shock to the PCBs 12, 16. A thermally conductive retainer 22B may hold the ceramic PCB 12 in place axially within the heat pipe or heat sink 22.

[0023] In some implementations, either or both the plastic PCB 16 and the ceramic PCB 12 may be a metal core PCB, such as may comprise a core layer made from copper, aluminum or other high themial conductivity metal to facilitate heat transfer from the respective PCB 12, 16. Example implementations of metal core PCBs may be obtained from San Francisco Circuits, Inc., 1660 S Amphlett Blvd #200, San Mateo, CA 94402 among other suppliers. Possible advantages of using metal core PCBs will be apparent from the description following with reference to FIGS. 3A through 3E. Ceramic PCBs may include a structural / insulating layer made from alumina or aluminum oxide (AI2O3), aluminum nitride (AIN), beryllia or beryllium oxide (BeO), silicon carbide (SiC), and boron nitride (BN), by way of example and without limitation. Example implementations of ceramic PCBs may be obtained from Millenium Circuits Limited, 7703 Derry St. Harrisburg, PA 17111.

[0024] FIGS. 3A through 3E show various views (FIG. 3A top plan view, FIG. 3B side view, FIG. 3C bottom plan view, FIG. 3D side cross-section and FIG. 3E oblique bottomview) of one example implementation of an axially stackable PCB assembly 25 (“PCB assembly”) according to the present disclosure. In the present example implementation, a ring shaped heat sink 30, e.g., in the form of a split, annular ring, such as may be made from aluminum, copper or other high thermal conductivity material, may surround circuit elements such as a PCB 34. The PCB 34 may be a single, plastic (resin - polyimide) PCB such as shown at 16 in FIGS. 2A and 2B, a ceramic PCB such as explained with reference to FIG. 2B and shown at 12, a metal core PCB such as may comprise a core made from, e.g., aluminum or copper and as explained above, or a combination PCB stack such as shown at 10 in FIGS. 1A, IB and 2A and as explained above. The PCB 34 may be in contact on one side with a heat transfer plate 32. In the case that the PCB 34 is a metal core PCB, thermal contact pads (not shown in the drawings) provided on one side of such PCBs may be disposed to be in contact with the heat transfer plate 32, wherein electronic components 33 mounted to the PCB 34 are disposed on the opposed, insulated side of the PCB 34.

[0025] The PCB 34 and the heat transfer plate 32 may be generally arranged or formed in a substantially circular, i.e., a closed, single perimeter shape having a high ratio of area to circumference, e.g., a high order polygon or circle or other shape as previously explained herein. The PCB 34 and the heat transfer plate 32 in any event may be shaped to fit tightly within the interior of the heat sink 30 to enable efficient heat transfer from the PCB 34 to the heat sink 30. A capture sleeve 36 may be disposed on an opposed side of the PCB 34 from the heat transfer plate 32 to retain the PCB 34 and the heat transfer plate 32 within the heat sink 30, e.g., against a shoulder 30A formed within the interior opening of the heat sink 30. The heat transfer plate 32 and the PCB 34 may comprise openings (not shown) to enable through wiring (not shown) between the PCB assembly 25 and longitudinally adjacent stackable PCB elements (see FIG. 4). The heat sink 30 may comprise openings 35 within the annular ring to enable mounting the heat sink 30 to one or more adjacent stackable PCB elements 25 of similar configuration as explained above, and / or to part of a well intervention tool (FIG. 4). Such openings 35 may be substantially perpendicular to a plane of the PCB 34. One side of the PCB 34 may comprise one or more electrical connectors 37 to enable electrical connection to a corresponding electrical cable (withsuitable gender connector) or to an adjacent stackable PCB element with a corresponding electrical connector on an opposed side of the heat transfer plate 32 (or PCB 34 if no heat transfer plate is used).

[0026] A common feature in each of the various implementations of PCBs and PCB assemblies explained with reference to FIGS. 1A through 3E above is that the plane of the PCBs may be arranged transversely to a longitudinal axis of a well intervention tool into which the PCBs and / or PCB assemblies are mounted. Such arrangement may optimize heat transfer from the PCBs to associated temperature control devices (e.g., and without limitation heat sinks and a housing in the associated intervention tool).

[0027] A possible advantage of PCB assemblies and stacks made as described above with reference to various example implementation is the relatively small area to thickness ratio of the PCBs. Such feature provides the PCBs with high resonant frequencies as compared to PCB structures used in well intervention tools known in the art prior to the present disclosure. Such relatively high resonant frequencies may reduce possibility of PCB failure as a result of induced resonance.

[0028] FIG. 4A shows a cross section transverse to the longitudinal axis L, and FIG. 4B shows a corresponding cross section along the longitudinal axis L of an example implementation of part 50 (“tool part”) of a well intervention tool 150 which may use one or more PCBs and / or PCB assemblies according to the present disclosure. Electronic components of the tool part 50 may be disposed inside an elongated, pressure resistant housing 52, which may be generally cylindrically shaped and have pressure resistance capability to withstand the maximum fluid pressure expected in any well in which the intervention tool is to be operated. The housing 52 may comprise at either or both longitudinal ends an adapter 53, which enables mechanical and electrical connection to another part (not shown) of the well intervention tool 150 or to a conveyance such as armored electrical cable, slickline, coiled tubing or jointed tubing. One or more through passages 54 may provide places to dispose electrical wiring and / or fluid channels through the tool part 50, depending on the particular well intervention tool and any other devices to which the tool part 50 may be connected. In the present example implementation, aplurality of PCB assemblies 25, each of which may be substantially as explained with reference to FIGS. 3A through 3E, may be mounted within the housing 52 such that the respective heat sinks (30 in FIGS. 3A through 3E) of each PCB assembly fit tightly within the interior of the housing 52 to enable efficient heat transfer between the heat sink(s) (30 in FIGS. 3A through 3E) and the housing 52. The PCB assemblies 25 may be disposed such that they are stacked along the longitudinal axis L of the tool part 50, such that the included PCB(s) are disposed with their respective plane(s) transverse to the longitudinal axis L, as explained with reference to FIGS. 3A through 3E.

[0029] In the present example implementation, an insulated container (e.g., a vacuum insulated container such as a Dewar flask) 41 may be disposed within the housing 52. The insulated container 41 may comprise in its interior a plurality of PCB assemblies 25 A made as explained with reference to FIGS. 3A through 3E and arranged such that the included PBC(s) are disposed with their plane(s) transverse to the longitudinal axis L. A diameter of the PCB assemblies 25A is chosen to fit within the internal diameter of the insulated container 41. The thermally insulated container 41 may comprise within its interior other components for temperature control, for example and without limitation, one or more thermoelectric coolers 47, thermal regulator valves 42 and a heat sink 44, which may be made from metal. A structural support 46 holds the thermally insulated container in place within the housing 52 on one longitudinal end. The other longitudinal end of the thermally insulated container 41 may comprise a thermally insulated plug 43, which thermally insulated plug may comprise an optical and / or electrical waveguide 45 for signal communication and / or electromagnetic induction couplings for communicating power and signals between circuits disposed on the PCB assemblies 25 and other devices outside the insulated container 41, e.g., circuitry on the stacked PCB assemblies shown at 25.

[0030] Advantageously, a well tool part such as shown at 50 in FIG. 4B may form part of a well intervention tool wherein the well tool part 50 is disposed within a fluid channel inside the well intervention tool, e.g., a measurement while drilling (MWD) or logging while drilling (LWD) tool. In such tools, fluid pumped from surface through a central bore in the tool conveyance (e.g., drill pipe, coiled tubing, jointed tubing or the like) may act to remove heat from the tool part 50, wherein such heat is transferred to the housing 52. Thearrangement of heat sink 30 (or heat pipe 22 in FIG. 2B) on the perimeter of the PCB(s) may optimize PCB cooling in such implementations.

[0031] In light of the principles and example implementations described and illustrated herein, it will be recognized that the example implementations can be modified in arrangement and detail without departing from such principles. The foregoing discussion has focused on specific implementations, but other configurations are also contemplated. In particular, even though expressions such as in “an implementation," or the like are used herein, these phrases are meant to generally reference implementation possibilities, and are not intended to limit the disclosure to particular implementation configurations. As used herein, these temis may reference the same or different implementations that are combinable into other implementations. As a rule, any implementation referenced herein is freely combinable with any one or more of the other implementations referenced herein, and any number of features of different implementations are combinable with one another, unless indicated otherwise. Although only a few examples have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible within the scope of the described examples. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims.

Claims

AMENDED CLAIMS received by the International Bureau on 18 February 2025 (18.02.2025)CLAIMS:What is claimed is:

1. A printed circuit board (PCB) assembly, comprising: at least one substantially circularly shaped PCB; a heat sink surrounding and in contact with substantially an entire perimeter of the at least one PCB; wherein the heat sink comprises at least one mounting feature enabling mounting within a well intervention tool such that a plane of the PCB is perpendicular to a longitudinal axis of the well intervention tool; and wherein a viscoelastic damping material is disposed between one side of the at least one PCB and a shoulder or ledge formed in an inner perimeter of the heat sink.

2. The assembly of claim 1 further comprising a heat transfer plate in contact with one side of the at least one PCB, the heat transfer plate being shaped to fit within and make circumferential contact with the heat sink.

3. The assembly of claim 1 further comprising at least a second substantially circularly shaped PCB disposed within and in perimeter contact with the heat sink, the at least a second PCB being axially spaced apart from the at least one PCB.

4. The assembly of claim 3 wherein the at least one PCB comprises plastic, and the at least a second PCB comprises ceramic, the ceramic PCB having mounted thereon electronic components generating more heat than electronic components mounted on the at least one PCB.

5. The assembly of claim 3 wherein the at least one PCB is mounted to the heat sink using a visco-elastic material.

6. The assembly of claim 1 wherein the PCB is mounted to the heat sink using a thermally conductive retainer ring.

7. The assembly of claim 1 wherein the at least one mounting feature comprises at least one opening formed through the heat sink in a direction substantially perpendicular to a plane of the at least one PCB.

8. The assembly of claim 1 wherein the heat sink is shaped as an annular ring.

9. A well intervention tool, comprising: an elongated housing shaped to traverse an interior of a well; at least one printed circuit board (PCB) assembly disposed in the housing, the at least one PCB assembly comprising at least one substantially circularly shaped PCB; a heat sink surrounding and in contact with substantially an entire perimeter of the at least one PCB; wherein the heat sink is mounted within the housing such that a plane of the PCB is perpendicular to a longitudinal axis of the housing; and wherein a viscoelastic damping material is disposed between one side of the at least one PCB and a shoulder or ledge formed in an inner perimeter of the heat sink.

10. The tool of claim 9 further comprising at least a second PCB assembly mounted in the housing adjacent to the at least one PCB assembly, the at least a second PCB assembly mounted such that a plane of a PCB forming part of the at least a second PCB assembly is perpendicular to the longitudinal axis.

11. The tool of claim 9 further comprising a heat transfer plate in contact with one side of the at least one PCB, the heat transfer plate being shaped to fit within and make circumferential contact with the heat sink.

12. The tool of claim 9 further comprising at least a second substantially circularly shaped PCB disposed within and in perimeter contact with the heat sink, the at least a second PCB being axially spaced apart from the at least one PCB.

13. The tool of claim 12 wherein the at least one PCB comprises plastic, and the at least a second PCB comprises ceramic, the ceramic PCB having mounted thereon electronic components generating more heat than electronic components mounted on the at least one PCB.

14. The tool of claim 12 wherein the at least one PCB is mounted to the heat sink using a viscoelastic material.

15. The tool of claim 9 wherein the PCB is mounted to the heat sink using a thermally conductive retainer ring.

16. The tool of claim 9 wherein the at least one mounting feature comprises at least one opening formed through the heat sink in a direction substantially perpendicular to a plane of the at least one PCB.

17. The tool of claim 9 wherein the heat sink is shaped as an annular ring.

18. A printed circuit board (PCB) assembly, comprising: at least one substantially circularly shaped PCB; a heat sink surrounding and in contact with substantially an entire perimeter of the at least one PCB; wherein the heat sink comprises at least one mounting feature enabling mounting within a well intervention tool such that a plane of the PCB is perpendicular to a longitudinal axis of the well intervention tool; at least a second substantially circularly shaped PCB disposed within and in perimeter contact with the heat sink, the at least a second PCB being axially spaced apart from the at least one PCB, and wherein the at least one PCB comprises plastic, and the at least a second PCB comprises ceramic, the ceramic PCB having mounted thereon electronic components generating more heat than electronic components mounted on the at least one PCB.

19. The assembly of claim 18 further comprising a heat transfer plate in contact with one side of the at least one PCB, the heat transfer plate being shaped to fit within and make circumferential contact with the heat sink.

20. The assembly of claim 18 wherein the at least one PCB is mounted to the heat sink using a visco-elastic material.

21. The assembly of claim 18 wherein the PCB is mounted to the heat sink using a thermally conductive retainer ring.

22. The assembly of claim 18 wherein the at least one mounting feature comprises at least one opening formed through the heat sink in a direction substantially perpendicular to a plane of the at least one PCB.

23. The assembly of claim 18 wherein the heat sink is shaped as an annular ring.

24. A well intervention tool, comprising: an elongated housing shaped to traverse an interior of a well; and at least one printed circuit board (PCB) assembly according to any of claims 18 through23.

25. The tool of claim 24 further comprising at least a second PCB assembly mounted in the housing adjacent to the at least one PCB assembly, the at least a second PCB assembly mounted such that a plane of a PCB forming part of the at least a second PCB assembly is perpendicular to the longitudinal axis.

26. The tool of claim 24 further comprising a heat transfer plate in contact with one side of the at least one PCB, the heat transfer plate being shaped to fit within and make circumferential contact with the heat sink.

27. The tool of claim 24 wherein the at least one PCB is mounted to the heat sink using a viscoelastic material.

28. The tool of claim 24 wherein the PCB is mounted to the heat sink using a thermally conductive retainer ring.

29. The tool of claim 24 wherein the at least one mounting feature comprises at least one opening formed through the heat sink in a direction substantially perpendicular to a plane of the at least one PCB.

30. The tool of claim 24 wherein the heat sink is shaped as an annular ring.

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