In sub-terrain drilling, downhole tools are often provided with various sensors to detect various downhole parameters. Sensors may be used for measuring, logging, telemetry, steering, and the like. The sensor measurement data may be processed by electronic components to evaluate the data, transmit the data, or use the measurement values for direct control. The electronic components must be able to withstand high temperatures, accelerations and other downhole environment conditions. The electronic components are typically built in the form of multi-chip module (MCM) electronics that are provided in recesses that are disposed in the downhole tool. MCM electronics are composed of dies (integrated circuits). These dies are sensitive to various gases e.g. fluorine and chlorine and therefor require a separate housing. The MCM housing is designed to protect the MCM electronics from harmful gases. A sleeve, or coverplate, generally covers the MCM housing. The sleeve, or coverplate, encapsulates the MCM housing to provide protection from hydrostatic drilling load forces and drilling mud.
A downhole tool in accordance with an exemplary embodiment includes a tool body having an inner surface portion and an outer surface portion. The outer surface portion includes a recess having a peripheral wall and an inner surface. A multi-chip module (MCM) housing is defined in the recess. MCM housing includes one or more fortifying members that support axial and radial loading of the downhole tool and one or more electronics receiving zones.
Referring now to the drawings wherein like elements are numbered alike in the several Figures:
A downhole tool, in accordance with an exemplary embodiment, is indicated generally at 2, in
As shown in
In accordance with an exemplary aspect, MCM housing 24 is supported in recess 12 upon inner surface 18 and thus may form part of a redundant assembly (not separately labeled) that may provide additional protection over and above that which may be provided by outer cover 30 to internally arranged components. Specifically, outer peripheral edge 53 and cantilevered end portions 58, 59 abut inner surface 18 and support portion 45. In this manner, MCM housing 24 is capable of withstanding hydrostatic loading and protects internal electronic components. Further, MCM housing 24 provides protection for the electronic components without increasing an overall radial thickness of downhole tool 2. Once in place, outer peripheral edge 53 may be bonded to tool body 4. For example, outer peripheral edge 53 may be welded or otherwise fused to edge 13 as shown in
Reference will now follow to
In accordance with the exemplary embodiment shown, MCM housing 70 is detachably mounted within recess 12 through a first seal 91 and may form part of a redundant assembly (not separately labeled) that provides additional protection over and above that which may be provided by outer cover 30 to internally arranged components. First seal 91 takes the form of a spring loaded radial seal 92 having a generally C-shaped cross-section. Of course, it should be understood that first seal 91 may take on a variety of geometries and may or may not be spring loaded. MCM housing 70 also includes a second seal 94. Second seal 94 takes the form of a spring loaded axial seal 96 similar to that described in connection with spring loaded radial seal 92. First and second seals 91 and 94 may be metallic seals formed from stainless steel, a metal alloy, silver, copper and gold, or may possess a metallic coating, such as stainless steel, a metal alloy, silver, copper and gold. The particular type of metallic coating may vary. The metallic coating is generally chosen to be non-reactive with downhole formation materials and/or mud. It should also be understood that MCM housing 70 may include a single continuous seal that extends both axially and radially. It should be further understood that MCM housing 70 may include an integral seal. Conversely, a seal may be built into tool body 4. Once installed, MCM housing 70 may be covered by outer sleeve 30. No longer required to accommodate all hydrostatic loading, outer sleeve 30 may now having a thinner cross section.
Reference will now be made to
In further accordance with the exemplary embodiment shown, downhole tool 2 includes a strengthening element 140 that extends across MCM housing 121. Strengthening element 140 includes a first surface portion 142 and an opposing, second surface portion 143. Second surface portion 143 includes a plurality of strengthening members, one of which is shown at 145, that correspond to each of the plurality of fortifying members 130. Strengthening element 140 provides a cover for MCM housing 121 as well as provides structure that may accommodate hydrostatic loading. Once in place, strengthening element 140 may be covered by a sleeve (not shown). No longer required to accommodate all hydrostatic loading, the sleeve may now have a thinner cross section. Strengthening element 140 may be bonded, such as through welding, or sealed with a metallic seal to fortifying members 130 to protect electronic components (not shown) in electronics receiving zones 134 from exposure to outgassing.
In accordance with an aspect of the exemplary embodiment, removable electronic component access member 179 may take the form of a detachable connector 180. Detachable connector 180 may take the form of a pressure feed through 184, arranged in first connector receiving zone 172. By “detachable”, it should be understood that connector 180 may be removed from connector receiving zone 172 without the need for severing welds, or other bonds, and that detachable connector 180 may be reused following removal. For example, detachable connector 180 may be threadably engaged with connector receiving zone 170, or may employ a shaped memory alloy material that may engage connector receiving zone 170 when exposed to elevated temperatures such as found in a downhole environment, clamping and the like. Detachable connector 180 may also be readily installed into first connector receiving zone 172 without the need for welds or other permanent means of attachment. For example, detachable connector 180 may be threadably engaged with connector receiving zone 170.
Pressure feed through 184 is connected to a conduit 190 that leads to an adjacent downhole component (not shown). As best shown in
In accordance with an exemplary embodiment, body 193 includes a step section 201 and a groove 204. Groove 204 extends circumferentially about body 193 and receives an electrical contact 207. Electrical contact 207 is radially outwardly biased to provide a connection between pressure feed through 184 and tool body 4 that may establish an electrical ground or a conductive pathway for other signals. In accordance with an exemplary aspect, electrical contact 207 defines a spring contact. Pressure feed through 184 also includes a seal 210 arranged at step section 201 of body 193. Seal 210 is positioned between step section 201 and first seal land 177 to prevent gasses from entering recess 168 while allowing connector 180 to be removed from tool body 4. In accordance with an aspect of the exemplary embodiment, seal may be formed from metal such as stainless steel, a metal alloy, silver, copper and gold, or may possess a metallic coating, such as stainless steel, a metal alloy, silver, copper and gold. The metallic coating is generally chosen to be substantially non-reactive with downhole formation materials.
In accordance with an aspect of an exemplary embodiment, detachable connector 180 not only facilitates easy and repeated installation and removal but also provides access to electronic components (not shown) housed in recess 168 in tool body 114. In further accordance with an aspect of an exemplary embodiment, tool body 114 may include a removable electronic component access member 300 in the form of a removable multi-chip module (MCM) housing 310 provided in recess 168. MCM housing 310 may be secured to tool body 114 in recess 168 through a metallic seal 320.
At this point it should be understood, that the exemplary embodiments describe a MCM housing that is capable of carrying a high percentage of hydrostatic pressure applied to a downhole tool as well as other applied loads such as those provided by threaded connections, drillstring torsion, bit weight, bit torque and the like. The MCM housing also protects electronic components from exposure to outgassing and other downhole conditions. Further, the MCM housing is formed from a material that is resistant to exposure to potentially corrosive downhole formations. It should also be understood, that the particular shape and internal geometry of the MCM housing may vary and could be adapted to a wide variety of applications.
It should be further understood, that the downhole tool in accordance with exemplary embodiments may form part of an overall downhole system 400, illustrated in
While one or more embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.