Abstract:
An apparatus for protecting an electronics module used in a borehole includes a borehole string section having at least one pocket is formed and a mount associated with the at least one pocket. The mount may include a housing, a lid, a biasing member, and a securing member. The housing receives the electronics module and is seated on a seating surface, which may be formed on the at least one pocket or the mount. The lid encloses the housing within the at least one pocket. The biasing member is in operative contact with the housing. The securing member secures the lid within the at least one pocket and compresses the lid, the housing and the biasing member in the pocket. The biasing member responsively urges the housing against the seating surface and the housing hermetically seals the electronic module.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 14/276331, filed May 13, 2014, the disclosure of which is incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE DISCLOSURE 
       [0002]    This disclosure pertains generally to devices and methods for providing shock and vibration protection for borehole devices. 
       BACKGROUND OF THE DISCLOSURE 
       [0003]    Exploration and production of hydrocarbons generally requires the use of various tools that are lowered into a borehole, such as drilling assemblies, measurement tools and production devices (e.g., fracturing tools). Electronic components may be disposed downhole for various purposes, such as control of downhole tools, communication with the surface and storage and analysis of data. Such electronic components typically include printed circuit boards (PCBs) that are packaged to provide protection from downhole conditions, including temperature, pressure, vibration and other thermo-mechanical stresses. 
         [0004]    In one aspect, the present disclosure addresses the need for enhanced shock and vibration protection for electronic components and other shock and vibration sensitive devices used in a borehole. 
       SUMMARY OF THE DISCLOSURE 
       [0005]    In aspects, the present disclosure provides an apparatus for protecting an electronics module used in a borehole. The apparatus may include a section of a borehole string having at least one pocket and a mount associated with the at least one pocket. The mount may include a housing, a lid, a biasing member, and a securing member. The housing receives the electronics module and is seated on a seating surface, which may be formed on the at least one pocket or the mount. The lid encloses the housing within the at least one pocket. The biasing member is in operative contact with the housing. The securing member secures the lid within the at least one pocket and compresses the lid, the housing and the biasing member in the pocket. The biasing member responsively urges the housing against the seating surface and the housing hermetically seals the electronic module. 
         [0006]    In aspects, the present disclosure also provides a method for protecting a module used in a borehole. The method may include forming at least one pocket in a section of a borehole string; and disposing a mount at least partially into the at least one pocket. The mount may include a housing, a lid, a biasing member, and a securing member. The housing receives the electronics module and is seated on a seating surface, which may be formed on the at least one pocket or the mount. The method also includes enclosing the housing within the at least one pocket using a lid, operatively contacting the housing with a biasing member, securing the lid within the at least one pocket using a securing member, the securing member compressing the lid, the housing and the biasing member in the pocket, the biasing member responsively urging the housing against the seating surface; and hermetically sealing the electronic module using the housing. 
         [0007]    Examples of certain features of the disclosure have been summarized rather broadly in order that the detailed description thereof that follows may be better understood and in order that the contributions they represent to the art may be appreciated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    For a detailed understanding of the present disclosure, reference should be made to the following detailed description of the embodiments, taken in conjunction with the accompanying drawings, in which like elements have been given like numerals, wherein: 
           [0009]      FIG. 1  shows a schematic of a well system that may use one or more mounts according to the present disclosure; 
           [0010]      FIG. 2  illustrates one embodiment of an electronics module that may be protected using a mount according to the present disclosure; 
           [0011]      FIG. 3  illustrates an end view of a section of a BHA that has a plurality of electronics protected by mounts according to one embodiment of the present disclosure; 
           [0012]      FIG. 4  illustrates a sectional view of a section of the BHA that includes a mount according to one embodiment of the present disclosure; and 
           [0013]      FIG. 5  illustrates a latching arrangement that may be used with a mount according to one embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Drilling conditions and dynamics produce sustained and intense shock and vibration events. These events can induce electronics failure, fatigue, and accelerated aging in the devices and components used in a drill string. In aspects, the present disclosure provides mountings and related methods for protecting these components from the energy associated with such shock events. 
         [0015]    Referring now to  FIG. 1 , there is shown one illustrative embodiment of a drilling system  10  utilizing a borehole string  12  that may include a bottomhole assembly (BHA)  14  for directionally drilling a borehole  16 . While a land-based rig is shown, these concepts and the methods are equally applicable to offshore drilling systems. The borehole string  12  may be suspended from a rig  20  and may include jointed tubulars or coiled tubing. In one configuration, the BHA  14  may include a drill bit  15 , a sensor sub  32 , a bidirectional communication and power module (BCPM)  34 , a formation evaluation (FE) sub  36 , and rotary power devices such as drilling motors  38 . The sensor sub  32  may include sensors for measuring near-bit direction (e.g., BHA azimuth and inclination, BHA coordinates, etc.) and sensors and tools for making rotary directional surveys. The system may also include information processing devices such as a surface controller  50  and/or a downhole controller  42 . Communication between the surface and the BHA  14  may use uplinks and/or downlinks generated by a mud-driven alternator, a mud pulser and/or conveyed using hard wires (e.g., electrical conductors, fiber optics), acoustic signals, EM or RF. 
         [0016]    One or more electronics modules  24  incorporated into the BHA  14  or other component of the borehole string  12  may include components as necessary to provide for data storage and processing, communication and/or control of the BHA  14 . These components may be disposed in suitable compartments formed in or on the borehole string  12 . Exemplary electronics in the electronics module include printed circuit board assemblies (PCBA) and multiple chip modules (MCM&#39;s). 
         [0017]    Referring to  FIG. 2 , there is shown one non-limiting embodiment of a module  24  that may be used with the borehole string  12  of  FIG. 1 . The module  24  can be a BHA&#39;s tool instrument module, which can be a crystal pressure or temperature detection, or frequency source, a sensor acoustic, gyro, accelerometer, magnetometer, etc., sensitive mechanical assembly, MEM, multichip module MCM, Printed circuit board assembly PCBA, flexible PCB Assembly, Hybrid PCBA mount, MCM with laminate substrate MCM-L, multichip module with ceramic substrate e.g. LCC or HCC, compact Integrated Circuit IC stacked assemblies with ball grid arrays or copper pile interconnect technology, etc. All these types of modules  24  often are made with fragile and brittle components which cannot take bending and torsion forces and therefore benefit from the protection of the package housing and layered protection described below. 
         [0018]    Exemplary mounts for protecting shock and vibration sensitive equipment such as the electronics module  24  are described below. Although the embodiments described herein are discussed in the context of electronics modules, the embodiments may be used in conjunction with any component that would benefit from a structure having high damping, high thermal conduction, and/or low fatigue stress. Furthermore, although embodiments herein are described in the context of downhole tools, components and applications, the embodiments are not so limited. 
         [0019]      FIG. 3  schematically illustrates a mount  100  for protecting a module  24  ( FIG. 2 ) from shock and vibration. The mount  100  may be formed in a section  102  of the borehole string  12  of  FIG. 1 . For example, the section  102  may be a drill collar, a sub, a portion of a jointed pipe, or the BHA  14 . The mount  100  may be secured within a pocket  104  formed on an outer circumferential surface  106  of the section  102 . A sleeve  110  surrounds the section  102  secures the mounts  100  within the pockets  104 . The sleeve  110  may be formed of a non-magnetic material such as stainless steel. While four mounts  100  are shown circumferentially distributed on the section  102 , it should be understood that greater or fewer number of mounts  100  may be used. In embodiments, one common continuous sleeve  110  secures a plurality of circumferentially distributed mounts  100 . 
         [0020]      FIG. 4  sectionally illustrates one embodiment of a mount  100  that may be used to resiliently secure the module  24  ( FIG. 2 ) within the pocket  104 . The pocket  104  may be pre-formed or machined (e.g., milled) into the section  102  and include passages  108  for wiring and other equipment that connect to the module  24  ( FIG. 2 ). The passages  108  may connect the pocket  104  with other compartments, chambers, or cavities that contain electrical equipment such as sensors (not shown). The mount  100  may include a housing  120 , a lid  130 , and a biasing member  140 . 
         [0021]    The housing  120  provides a hermetically sealed environment for the module  24  ( FIG. 2 ). The housing  120  may include a sealed casing  122  formed of a metal such as titanium or Kovar. These types of metals have a thermal expansion similar to the ceramic, glass, composite, or other material used to encase the module  24  ( FIG. 2 ). Electrical connections to the module  24  may be made using the internal connectors  124  and the external connectors  126 . It should be understood that the shown configuration for the housing  120  is merely one non-limiting example of a housing  120  that may be used in connection with mounts  100  according to the present disclosure. 
         [0022]    The lid  130  encloses the housing  120  within the pocket  104 . The lid  130  may include a recess  132  for receiving the biasing element  140  and the housing  120 . The recess  132  may include a shoulder  134  or other similar feature that contacts the housing  120  to minimize movement in the axial direction. As used herein, the term axial refers to a longitudinal directional along the borehole string  12  ( FIG. 1 ). Referring to  FIG. 5 , the lid  130  may optionally include latches  136  that secure the lid  130  within the pocket  104 . The latches  136  may be positioned at an end  138  of the lid  30  and include spring-biased balls or other locking mechanisms engage a suitable profile  137  formed in the pocket  104 . The lid  130  may be formed of a suitable non-magnetic material such as stainless steel. Additionally, the lid  130  may include a ramped or sloped portions  139  that allow the sleeve  110  to slide over the lid  130  during final installation. 
         [0023]    The biasing member  140  applies a spring force that presses the housing  120  against a seating surface  128  of the pocket  104 . The biasing member  140  may be any structure that has range of elastic deformation sufficient to generate a persistent spring force. As shown, the biasing member  140  may be a leaf spring that has one or more apex regions  142  that compressively contact the housing  120 . While the apex regions  142  are shown in a medial section of the biasing member  140 , it should be understood that the apex regions  142  may distributed throughout the biasing member  140 . For instance, apex regions  142  may be located at a distal end  144  of the biasing member  120 . Other springs such as coil springs or spring washers, may be used. Additionally, pressurized fluids may be used to generate a spring force. Also, while point contacts are shown, it should be understood that the biasing member  140  may be formed as a body such as a pad that distributes compressive force of a relatively large surface area. The biasing member  140  may be retained in a suitable groove or slot in the recess  132 . 
         [0024]    Some embodiments may include a heat transfer pad  160  positioned between the housing  120  and the seating surface  128 . One non-limiting embodiment of a heat transfer pad  160  may be formed at least partially of a visco-elastic material. As used herein, a viscoelastic material is a material having both viscous and elastic characteristics when undergoing deformation. More generally, the heat transfer pad  160  may be formed of any material that transfers heat from the housing  120  to the section  102  and/or provides shock absorption. 
         [0025]    It should be understood that the mounts according to the present disclosure are susceptible to numerous variants. For example, circumferential springs may be used to fix the mounts inside the pocket. 
         [0026]    Referring not to  FIGS. 1-5 , in one mode of use, each module  24  is first inserted into a housing  120 . The internal electrical connections  124  are made up and the housing  120  is hermetically sealed. Next, the housing  120  is disposed into the pocket  104  and wires (not shown) are connected to the external electrical connections  126 . The lid  130  and biasing member  140  are then set over the housing  120 . Depressing the lid  130  allows the latching members  136  to snap the lid  130  into place in the pocket  104 . After all the modules  24  are installed, the sleeve  110  is slid over the pockets  104 . The sleeve  110  interferingly engages the lid  130  because an inner surface of the sleeve  110  is more radially inward that an outer surface of the lid  130  when the lid  130  rests on a relaxed biasing member  140 . This interfering engagement forces the lid  130  move radially inward, which compresses the biasing member  140 . In response to being compressed, the biasing member  140  presses the housing  120  against the heat transfer pad  160 . Thus, the module  24  is restrained against lateral motion; i.e., motion transverse to the longitudinal axis of the tool. Additionally, the shoulder  134  of the lid  130  and frictional forces at the heat transfer pad  160  minimize movement of the housing  130  in the axial direction or sliding motion generally. 
         [0027]    During drilling or other activities in the borehole  16 , the section  102  may encounter shocks and vibrations. Advantageously, the mount  100  minimizes movement of the housing  120  and enclosed module  24  in the lateral and axial directions when subjected to these movements. Also, the heat transfer pad  160  conducts heat from the housing  120  to a suitable heat sink, such as a drilling mud flowing in the borehole string  12 . 
         [0028]    While the foregoing disclosure is directed to the one mode embodiments of the disclosure, various modifications will be apparent to those skilled in the art. It is intended that all variations be embraced by the foregoing disclosure.