Abstract:
An apparatus for protecting a module used in a borehole may include a plurality of shock protection elements associated with the module. The plurality of shock protection elements cooperatively has a macroscopic non-linear spring response to an applied shock event. The plurality of shock protection elements may include at least an enclosure and a dampener connecting the module with the enclosure. A related method for protecting a module used in a borehole may include enclosing the module within the plurality of shock protection elements; disposing the module in the borehole; and subjecting the module to a shock event. The plurality of shock protection elements cooperatively has a macroscopic non-linear spring response to the shock event.

Description:
FIELD OF THE DISCLOSURE 
     This disclosure pertains generally to devices and methods for providing shock and vibration protection for wellbore devices. 
     BACKGROUND OF THE DISCLOSURE 
     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. 
     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 wellbore. 
     SUMMARY OF THE DISCLOSURE 
     In aspects, the present disclosure provides an apparatus for protecting a module used in a borehole. The apparatus may include a plurality of shock protection elements associated with the module. The plurality of shock protection elements cooperatively have a macroscopic non-linear spring response to an applied shock event. The plurality of shock protection elements may include at least an enclosure and a dampener connecting the module with the enclosure. 
     In aspects, the present disclosure provides a method for protecting a module used in a borehole. The method may include enclosing the module within a plurality of shock protection elements, wherein the plurality of shock protection elements includes at least: an enclosure and a dampener connecting the module with the enclosure; disposing the module in the borehole; and subjecting the module to a shock event, wherein the plurality of shock protection elements cooperatively have a macroscopic non-linear spring response to the shock event. 
     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 
       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: 
         FIG. 1  shows a schematic of a well system that may use one or more shock protectors according to the present disclosure; 
         FIG. 2A  schematically illustrates one embodiment of a shock protector that uses elongated supports according to the present disclosure; 
         FIG. 2B  isometrically illustrates the  FIG. 2A  shock protector; 
         FIG. 3A  schematically illustrates one embodiment of a shock protector that uses multiple shock absorbing and attenuating layers according to the present disclosure; 
         FIG. 3B  shows a graph of a representative behavior of the  FIG. 3A  shock protector during a shock event; 
         FIG. 4A  schematically illustrates one embodiment of a shock protector that includes a porous media having a fluid according to the present disclosure; 
         FIG. 4B  schematically illustrates representative fluid movement for the  FIG. 4A  shock protector during a shock event; 
         FIG. 5  schematically illustrates one embodiment of a shock protector that uses a lattice structure according to the present disclosure; 
         FIG. 6A  schematically illustrates one embodiment of a shock protector that uses a resilient grommet according to the present disclosure; 
         FIG. 6B  schematically illustrates one embodiment of a resilient grommet that uses a fluid according to the present disclosure; 
         FIG. 6C  schematically illustrates one embodiment of a resilient grommet that uses multiple resilient layers according to the present disclosure; 
         FIG. 6D  isometrically illustrates a embodiment according to the present disclosure that uses multiple resilient grommets oriented along different planes; 
         FIG. 7A  schematically illustrates the positioning of a shock protector and associated electronics module in a drill string annulus; 
         FIG. 7B  schematically illustrates an exemplary shock protector that is used to protect an electronics module that is mounted directly to a section of a drill string; 
         FIG. 7C  schematically illustrates the electrical connections that may be sued in connection with shock protectors according to the present disclosure; 
         FIG. 7D-E  schematically illustrate an exemplary shock protector according to embodiments of the present disclosure that may be used with a packaging module positioned in a hatch; and 
         FIG. 7F  schematically illustrates a sectional side view of the  FIG. 7E  embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     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 devices and methods for protecting these components from the energy associated with such shock events. Embodiments of the present disclosure may use layered, graded, and/or damping structures combined with structural elements and materials to achieve macroscopic non-linear spring behavior, attenuation, and dissipation. These structures can protect sensors, electronics and assemblies from vibration and shock energy. In some embodiments, the layers could exhibit elastomeric, viscoelastic, damping, or hydropneumatic characteristics. The structures and methods of the present disclosure can minimize structural damage, elastic deformation limitations, and cyclic fatigue due to deformation by limiting the instantaneous mechanical power (P(t)) level coupled to the structure during shock events and random vibrations. 
     Referring to  FIG. 1 , an exemplary embodiment of a well logging, production and/or drilling system  10  includes a conveyance device such as a borehole string  12  that is shown disposed in a borehole  14  that penetrates at least one earth formation  16  during a drilling, well logging and/or hydrocarbon production operation. The conveyance device can include one or more pipe sections, coiled tubing forming segments of a tool string, a downhole tractor, or a drop tool. In one embodiment, the system  10  also includes a bottomhole assembly (BHA)  20 . In one embodiment, the BHA  20 , or other portion of the borehole string  12 , includes a drilling assembly and/or a measurement assembly such as a downhole tool  22  configured to estimate at least one property of the formation  14 , the BHA  20 , and/or the borehole string  12 . 
     The tool  22  is connected to suitable electronics for receiving sensor measurements, storing or transmitting data, analyzing data, controlling the tool and/or performing other functions. Such electronics may be incorporated downhole in an electronics module  24  incorporated as part of the tool  22  or other component of the string  12 , and/or a surface processing unit  26 . In one embodiment, the electronics module  24  and/or the surface processing unit  26  includes components as necessary to provide for data storage and processing, communication and/or control of the tool  22 . Exemplary electronics in the electronics module include printed circuit board assemblies (PCBA) and multiple chip modules (MCM&#39;s). 
     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. 
     Exemplary structures for protecting shock and vibration sensitive equipment such as the electronics module  24  ( FIG. 1 ) are described below. For ease of discussion, such structures will be referred to as shock protectors. It should be understood, however, that these structures are equally effective at protecting equipment from vibrations. 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. 
       FIGS. 2A-B  sectionally illustrate one embodiment of a shock protector  100  for protecting a pair of modules  24  from shock and vibrations.  FIG. 2A  is a sectional view of the shock protector  100  that is isometrically shown in  FIG. 2B . The modules  24  may be secured in a chassis  50  formed as an “H-beam.” The shock protector  100  may include plurality of resilient supports  102  that are distributed around the chassis  50  and one or more pads  104  inserted between each module  24  and the chassis  50 . In this non-limiting embodiment, two pairs of differently sized supports  102  are used. As used herein, the term “resilient” refers to a connection wherein the material has an elastic deformation zone and a plastic deformation zone and wherein the elastic deformation zone has the ability to absorb/dissipate at least a portion of the energy associated with a shock event. A pressure barrel  106  encloses the shock protector  100  and the modules  24 . The shock protector  100  and associated electronics module  24  are positioned inside the bore of a string  12  ( FIG. 1 ) such that drilling mud flow surrounds and immerses the pressure barrel  106 . 
     In one arrangement, the supports  102  form a resilient connection between the module  24  and the pressure barrel  106 . Thus, in one sense, the module  24  may be considered to be suspended in the pressure barrel  106  by the supports  102 . The supports  102  may be formed as strips that are elongated along a longitudinal tool axis  54  ( FIG. 2B ). The axial length of the supports  102  may be selected to resist tool body motion at “anti-nodes.” During operation, sinusoidal waves may propagate along the drill string  12  ( FIG. 1 ) and BHA  20  ( FIG. 1 ). These waves cause the drill string  12  ( FIG. 1 ) and BHA  20  ( FIG. 1 ) to be laterally displaced relative to the axis  54  ( FIG. 2B ). Locations of maximum displacement (or amplitude) are referred to as anti-nodes. In one arrangement, methods such as simulations or test runs may be used to locate the anti-nodes along the BHA  20  ( FIG. 1 ) and to determine the resonance and transmissibility. The supports  102  may be placed along the length to provide stiffness and dampening for the module  24 . For example, the supports  102  may have an axial length sufficient to prevent the pressure barrel  106  from pivoting about the compressive contact point at the supports  102 . 
     In embodiments, the supports  102  may be circumferentially arrayed around and fixed to the chassis  50 . For example, the supports  102  may be phased at ninety degree intervals as shown. While four supports  102  are shown, a greater or a fewer number of supports may be used. In embodiments, the supports  102  are symmetrically arranged such that opposing supports  102  can work cooperatively to attenuate and dissipate shock and vibration energy. 
     The support  102  may include a body  110  and a plurality of ribs  112  disposed on an outer surface  114 . The height of the ribs  112  is greater than the clearance space between the outer surface  114  and an interior surface  116  of the pressure housing  106 . Thus, the ribs  112  compress and cause a pre-determined amount of pre-loading on the body  110  after the module  24  has been inserted into the pressure housing  106 . Additionally, the shape and the volume of the body  110  may be selected to induce primarily shear stresses during shock events. In the embodiment shown, the body  110  has a domed portion  117  having a mass selected to absorb the shear strain associated with the anticipated shock events. Additionally, the ribs  112  and the body  110  may be shaped to generate a relatively high shear strain as opposed to a pure compressive loading in the body  110 . 
     In one embodiment, the supports  102  are formed of a composite material that exhibits high damping behavior. Suitable materials for the support  102  have an elastic modulus in the range of 100 to about 200 MPa such as Dow Corning&#39;s 1-4173. One non-limiting suitable material has glass fibers in an elastomeric binder. The composite material is a high temperature material whose performance is not affected by high temperatures. 
     The pressure barrel  106  acts as a protective enclosure for the electronics module  24  (hereafter “module”) and may be formed of a relatively hard material such as a metal. The pad  104  may be configured in one embodiment as a visco-elastic damping pad or damping layer that is disposed between the module  24  and the chassis  50 . The viscoelastic material has a stiffness corresponding to an elastic modulus that is in the range of, e.g., about 0.5 to about 5 MPa. An exemplary viscoelastic material is a polymer or elastomer such as DOW CORNING 3-6651 thermally conductive elastomer. 
     It should be appreciated that the  FIG. 2A  embodiment uses a layered structure for managing shock events. Initially, the pressure barrel  106  absorbs some of the shock energy and communicates the remainder to the supports  102 . The compressive contact at the ribs  112  causes this shock energy to generate shear strain in the body  110 . The material of the body  110  dampens the shock before the shock energy is transmitted to the chassis  50  and the module  24 . Further dampening is provided by the pads  104 , which dampen the movement of the module  24 . It should be appreciate that the above-described embodiment minimizes the scalar product of the force vector generated by the shock event and the velocity vector of the module  24 . Thus, external kinetic energy is absorbed and dissipated away from the module  24 . As should also be appreciated, the geometry, materials, and positioning of each of these elements may be configured as needed to attenuate and dissipate the anticipated shock and vibration energy. 
     Referring now to  FIG. 3A , there is shown another embodiment of the present disclosure that uses a shock protector  100  that includes multiple layers  142 ,  144 ,  146  that partially or completely surround the module  24 . By partially surround, it is meant enclosing at least two sides of the module  24 . By completely surround, it is meant enclosing all sides of the module  24 , but having what passages are needed to allow wiring to enter and connect to the module  24 . At least one of the layers  142 - 146  may be resilient. The layers  142 - 146  may be symmetric, continuously graded, or have discrete steps. Each layer  142 - 146  may have distinct damping and visco-elastic properties that allow the layers  142 - 146  to cooperatively protect the module  24  from impact and vibration. 
     The layers  142 - 146  may be configured to exhibit a composite non-linear spring behavior. The geometry and material for each layer  142 - 146  may be designed to respond to different ranges of the shock (transient) and vibration (random) frequency spectrum. Further, the layers  142 - 146  may be constructed such that they are energized and compressed sequentially during the shock event. The serial and sequential action of layers  142 - 146  with varying viscoelastic and damping characteristics may produce a nonlinear macroscopic damping spring effect. Thus, these shock protection elements/layers cooperatively have a macroscopic non-linear spring response to an applied shock event. 
     The representative behavior of each layer  142 - 146  in response to an applied shock energy is illustrated in the graph  148  of  FIG. 3B . Graph  148  shows frequency (Hz) along the “x-axis” and effective attenuation of shock and vibration (dB) along the “y-axis.” The graph  148  further illustrates the response of three layers  142 ,  144 ,  146  to an applied shock event. Each layer  142 ,  144 ,  146  is configured to have a different response as shown by lines  150 ,  152 ,  154 , respectively. However, the responses  150 ,  152 ,  154 , in the aggregate result in a net effective attenuation shown by line  156 . Line  156  illustrates the external package surface interaction to internal module&#39;s structure isolation. 
     The different responses may be obtained by varying one or more material properties or geometric properties: e.g., thickness, volumetric mass density, stiffness, dampening, creep, relaxation, resonance peak, Q-factor, specific damping capacity, loss angle d (delta), Beta angle, free natural frequency, free decay of vibration, tensile strength at break, elongation at break, creep ratio, tensile elastic stress (% strain), compression set, compressive stress (% strain), tear strength, bulk modulus, Poisson&#39;s ratio, static and kinetic coefficient of friction, density, specific gravity, glass transition, flash ignition temperature, resilience test rebound height, dielectric strength, dynamic young modulus (frequency), tangent delta (frequency), damping ratio, bacterial and fungal resistance, chemical resistance to fluids (hydraulic, kerosene, diesel, soap solution, etc . . . ), acoustic transmission loss in air, shock absorption life cycles, damping coefficient temperature range, percent load deflection hysteresis, etc. 
     A representative list of suitable materials includes, but is not limited to, microlayers (e.g., 10-100 microns thick) that alternate between at least one gas barrier (e.g., pressurized bladder) material and at least one elastomeric material; a thermoset, polyether-based, polyurethane, viscoelastic material such as SORBOTHANE. As used herein, a viscoelastic material is a material having both viscous and elastic characteristics when undergoing deformation. Generally speaking, a visco-elastic material deforms at under load and transmits forces in a plurality of directions and returns to its original shape when the load is removed. The deformation is at a molecular level or, stated differently, a molecular rearrangement. Additionally, a visco-elastic material has a relatively high tangent of delta. The tangent of delta is a dimensionless term that expresses the out-of-phase time relationship between a shock event and the transfer of the force to an object. In some embodiments, the properties of a suitable viscoelastic material may be: a tensile strength at breaking of 190 to 220 PSI, a bulk modulus of 2-3 gPascal, a Poisson&#39;s Ration of 0.4 to 0.6, a Dynamics Young&#39;s Modulus between 5 to 50 Hertz of 100-300, and a Tangent Delta between 5 to 50 Hertz of 0.4-0.6. 
     Referring now to  FIG. 4A , there is shown another shock protector  100  according to the present disclosure that also uses one or more layers  170  that partially or completely surround an electronics module  24 . In this embodiment, at least one of the layers  170  includes a network matrix of interconnected porous spaces filled with a fluid. When subjected to an external shock or vibration, the fluid moves partially or completely around the electronics module  24  via the porous interconnected channels. By partially, it is meant the fluid flows along less than all of the sides of the module  24 . By completely, it is meant the fluid completes a flow between two opposing sides of the module  24 . Thus, the fluid acts as a damping hydraulic action fluid. As shown and relative to the direction of the shock event, the fluid may initially move in a non-parallel direction. The flow may switch to a flow that aligns with the direction of the shock event and then back to a non-parallel flow. 
       FIG. 4B  illustrates fluid movement during a shock event. The fluid  180  is shown in a cell structure  182 . The fluid may be a liquid, a gas, a gel, a grease, or any other substance that can flow. A shock  184  is shown in what will be referred to as an axial direction. The fluid  180  reacts by flowing in a non-axial direction shown by arrows  186 ,  188 . The arrows  186 ,  188  are non-parallel with the direction of the shock  184 . As shown, this non-axial direction may be orthogonal or the flow vector may have an orthogonal and axial component. The non-axial movement of the fluid deflects the energy of the shock event to thereby protect the electronics module  24 . 
     The  FIG. 4B  shock protector  100  may use a cell structure  182  that is either open or closed. That is, the cell structure  182  may be permeable and allow fluid to circulate around the electronics module  24  through interconnected pores. The cell structure  182  may also be closed. In the closed cell structure  182 , the fluid may be trapped in cavities that deform (e.g., from a circle to an oval). 
     In embodiments not shown, the fluid may be a film between two surfaces. One or both of the surfaces may be coated with a material that chemically or physically interacts with the grease. For example, a grease film may be interposed between two coated plates. Reducing the gap between the plates forces a lateral movement of the grease film. 
     Referring now to  FIG. 5 , there is shown still another exemplary shock protector  100  according to the present disclosure for protecting an electronics module  24  from shock and vibration. In this arrangement, the module  24  is positioned in an annular space  220  between an inner tubular  222  and an outer tubular  224 . The drilling fluid flows through a bore  230  of the inner tubular  222 . The shock protector  100  may use a lattice  230  to dissipate shock energy and to transfer shock energy around the module  24 . The lattice  230  may also be engineered to have ESD protection characteristics, thermal conductivity and/or heat dissipation characteristics. 
     The lattice  230  may use a complex three dimensional architecture that is adapted to manage multi-axial shock loadings. The architecture may include a number of members configured to transfer primarily bending, primarily tension, and/or primarily compression loadings. By “primarily,” it is meant that the member is specifically engineered for a specific type of loading: e.g., a truss  240  or other similar triangular structure that is constructed with straight members whose ends are connected at joints and oriented to handle tension and compression loads; columns  242  for transmitting compression loads; a base  244  for supporting the columns  242  and other structural members; a dome  246  that functions as an outer or external protective body; a girt  248  or horizontal beam for stabilizing a primary structure (e.g. column  242 ); and gusset plates  248  or similar relatively thick and rigid sheets for connecting girts  248  beams to columns  242  or to connect truss members  240 . These features may all have different orientations, connections (e.g., fixed versus articulated), and shapes (e.g., plates, rods, strips, bars, etc.). During shock loadings, the lattice  230  communicates the loadings around the module. 
     In certain embodiments, one or more fastening members  250  such as latches may be used for quick assembly or disassembly of the packaging of the module  24 . The fastening member  250  may be used to lock together the dome  246  and the other described structural elements. Some embodiments may also include a thermal coupling pad  250  that draws heat away from the module  24  and conveys the heat sink such as the flowing drilling fluid  252 . 
     Referring now to  FIG. 6A-C , there is shown still another embodiment of a shock protector  100  according to the present disclosure for protecting a module  24 . The shock protector  100  may include a pad  282  and one or more grommets  284 . The pad  282  may be formed of a visco-elastic material and inserted between the module  24  and a surrounding base  286 . The grommet  284  may be formed as a sleeve-like tubular that surrounds a fastener  288  that secures the module  24  to the base  286  through a suitable attachment (e.g., threaded connection). As discussed below, the grommets  284  allow the connection between the module  24  and the base  286  to be resilient. 
       FIG. 6B  illustrates one configuration of a grommet  284  that includes an enclosure  292  and a porous material  294 . The porous material  294  may be distributed in a flow channel  296  that connects an upper compartment  298  with a lower compartment  300 . The enclosure  296  is sufficiently deformable to allow volume changes in the compartments  298 ,  300 . A viscous fluid  302 , such as grease, flows between the compartments  294 ,  296  during the volume changes. This fluid flow may be used to dampen and absorb vibrations as generally described in connection with the shock absorber described in connection with  FIGS. 4A  and B. 
       FIG. 6C  illustrates another configuration of a grommet  284  that includes an enclosure  312  and a layered body  314  disposed in an upper compartment  316  with a lower compartment  318 . The enclosure  296  is sufficiently deformable to transmit loadings to the layered bodies  314 . The layered bodies  314  may be constructed in the same manner and dampen/absorb vibrations as generally described in connection with the shock protector described in connection with  FIGS. 3A  and B. 
       FIG. 6D  illustrates another configuration wherein a plurality of grommet  284   a - c  are arranged to provide shock and vibration management along multiple axes; e.g., an x-axis  291 , a y-axis  293 , and a z-axis. The grommets  284   a - c  each have layered bodies  314   a - c . The layered bodies  314   a - c  may be constructed in the same manner and dampen/absorb vibrations as generally described in connection with the shock protector described in connection with  FIGS. 3A  and B. In this embodiment, each of the layered bodies redirect the energy of a shock event along a different plane. Thus, layered body  314   a  may direct energy along a plane that is non-parallel with the x-axis  291 , layered body  314   b  may direct energy along a plane that is non-parallel with the y-axis  293 , and layered body  314   c  may direct energy along a plane that is non-parallel with the z-axis  295 . 
     Embodiments of the present disclosure may be used anywhere in and along a drill string  12 . As discussed previously in connection with  FIGS. 2A  and B, the shock protector  100  and associated electronics module  24  may be positioned inside a stream of the flowing drilling fluid. Referring to  FIG. 7A , the shock protector  100  and associated module  24  may be positioned in an annulus  330  between an outer tubular  332  and an inner tubular  334 . The drilling fluid may flow through the bore of the inner tubular  324 . 
       FIG. 7B  shows a shock protector  100  and associated module  24  may be positioned in an annulus  330  between an outer tubular  332  and an inner tubular  334 . The drilling fluid may flow through the bore of the inner tubular  324 . In this embodiment, the shock protector  100  and the associate module  24  are fixed on a pocket  350  formed in the other tubular  332 . The module  24  may be positioned in a package housing  370 . The pocket  350  may be a section of the outer tubular  332  that has been cut away. The pocket  350  may be secured using a hatch cover  352 . Access to the electronics module  34  may be through a routing tube  354  and wiring  356   354  routed to other tool functional modules in the Bottom hole assembly (BHA) or probe assembly. As described previously, the shock protector  100  has a layered body  358 , which may be any of the layered bodies described previously. During a shock event  360 , the layered body  358  redirects the shock energy around the module  24  as shown by arrow  362 . 
     Referring now to  FIG. 7C , the protective package housing  370 , which is may be metallic (e.g., Kovar, stainless steel, titanium, etc. . . . ), supports the hatch cover  352  during deflection due to a shock event  360  or external borehole pressure. The housing  370  can include hermetically sealed connectors  371  for wires and conductors that provide the module  24  with electrical communication with modules (not shown) external to the module  24 . The housing  370  also includes through a hermetically sealed connector or a pressure feed-through connector  372  for allowing electrical communication through the package housing  370 . A wire connection  373  in the form of a wire bundle, flexible circuit, conductors ribbon, etc. provides signal and/or data communication between the connectors  371  and  372 . The connectors  372  connect with external wiring  356  installed and guided through a BHA wiring routing path  354  such as tubes, cut away, bored routing pathways inside the BHA, etc. 
     The package housing  370  fits tight inside the hatch pocket  350  and is designed to flex as the hatch cover  352  is deformed during impact or external borehole pressure  360 . The housing package  370  and the protective layers  358  do not allow the stress and strain deflections imposed on the housing package  370  to be coupled to the module  24 . Thus, the housing package  370  and the protective layers  358  prevent the module  24  from bending or being mechanically stressed in addition to minimizing vibration and shock mechanical energy that may be transferred to the module  24 . 
     Referring now to  FIG. 7D , the protective package housing  370  of the module  24 , which is installed inside the hatch pocket  350 , serves as a mechanical path load. The package housing  370  acts as a structural working member inside the hatch pocket  350  and supports the hatch cover  352  from collapsing inward under external borehole pressure or impact  360 . 
     Referring to  FIG. 7E , the module  24  may be mounted inside a package housing  370  and internally mounted on a substrate of layers  358 . The layers  358  may be installed in one side of the module  24 . Also, the substrate layers  358  may be extended to provide attachment to the sides of the module  24  as shown in  FIG. 7F . 
     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.