The present invention relates generally to an apparatus for use in the repair of drill bits for drilling subterranean formations, and an electronics module end-cap configuration for use therewith.
The oil and gas industry expends sizable sums to design rotary drilling and reaming tools, such as downhole drill bits including roller cone or “rock” bits as well as fixed cutter or “drag” bits, which have relatively long service lives, with relatively infrequent failure. In particular, considerable sums are expended to design and manufacture roller cone bits and fixed cutter bits in a manner that minimizes the opportunity for catastrophic drill bit failure during drilling operations. The loss of a roller cone or a polycrystalline diamond compact (PDC) from a fixed cutter bit during drilling operations can impede the drilling operations and, at worst, necessitate rather expensive fishing operations. If the fishing operations fail, sidetrack-drilling operations must be performed in order to drill around the portion of the wellbore that includes the lost roller cones or PDC cutters. Typically, during drilling operations, bits are pulled and replaced with new bits even though significant service could be obtained from the replaced bit. These premature replacements of downhole drill bits are expensive, since each trip out of and back into the well prolongs the overall drilling activity, and consumes considerable manpower. However, they are nevertheless done in order to avoid the far more disruptive and expensive process of, at best, pulling the drill drillstring and replacing the bit or fishing and sidetrack drilling operations necessary if one or more cones or PDC cutters are lost due to bit failure.
With the ever-increasing need for downhole drilling system dynamic data, a number of “subs” (i.e., a sub-assembly incorporated into the drillstring above the drill bit and used to collect data relating to drilling parameters) have been designed and installed in drillstrings. Unfortunately, these subs cannot provide actual data for what is happening operationally at the bit due to their physical placement above the bit itself.
Data acquisition is conventionally accomplished by mounting a sub in the bottom hole assembly (BHA), which may be several feet to tens of feet away from the bit. Data gathered from a sub this far away from the bit may not accurately reflect what is happening directly at the bit while drilling occurs. Often, this lack of data leads to conjecture as to what may have caused a bit to fail or why a bit performed so well, with no directly relevant facts or data to correlate to the performance of the bit.
Recently, data acquisition systems have been proposed to install in the drill bit itself. However, data gathering, storing, and reporting from these systems have been limited. In addition, conventional data gathering in drill bits has not had the capability to adapt to drilling events that may be of interest in a manner allowing more detailed data gathering and analysis when these events occur.
However, the assignee of the present invention has developed a data acquisition system for disposition in the drill bit itself and, specifically, in the shank of such a drill bit, to obtain performance data about the bit during its operation in drilling. This data acquisition system is marketed as the DATABIT™ system by Hughes Christensen, an operating unit of Baker Hughes Incorporated. Embodiments of the DATABIT™ system and its manufacture and use are disclosed in U.S. patent application Ser. No. 11/146,934, filed Jun. 7, 2005 and entitled METHOD AND APPARATUS FOR COLLECTING DRILL BIT PERFORMANCE DATA, the disclosure of which application is incorporated in its entirety herein by reference.
As use of this system, which comprises an electronics module received in the bit shank, has become more widespread, there have been occurrences where the module has been inadvertently left in the bit shank while a bit so equipped has undergone repair. Such repair includes heating in a furnace prior to replacement of damaged components such as PDC cutters, causing damage to the module due to thermal degradation. Such damage includes destruction of electronic components, and may initiate rupture of batteries in the module. Thus there is a need during the repair of such drill bits to ensure that the drill bit does not include such a module therein.
Embodiments of the present invention include a safety support pin configured as a spindle and an associated system and process for use when repairing a drill bit having an electronics module module disposed within the bit shank.
Further embodiments of the present invention include an end-cap for carrying an electronics module within a drill bit shank and configured with a bore to prevent the safety support pin spindle from being received in the shank of a drill bit having the end-cap received therein.
The present invention comprises an apparatus and method for use in the repair of a drill bit having a data acquisition system to determine if electronics disposed therein have been removed. As used herein, the terms “data acquisition system” and “electronics module” include and encompass instrumentation for acquiring and storing and, optionally, analyzing data relating to any selected downhole parameter or parameters, including but not limited to drill bit performance, and without limitation to portions of such systems such a sensors, microprocessors, memory, and power sources.
To illustrate an environment for a drill bit with which the present invention may be used during the repair thereof,
During drilling operations, drilling fluid is circulated from a mud pit 160 through a mud pump 162, through a de-surger 164, and through a mud supply line 166 into the swivel 120. The drilling mud (also referred to as drilling fluid) flows through the Kelly joint 122 and into an axial central bore in the drillstring 140. Eventually, it exits through apertures or nozzles, which are located in a drill bit 200, which is connected to the lowermost portion of the drillstring 140 below drill collar section 144. The drilling mud flows back up through an annular space between the outer surface of the drillstring 140 and the inner surface of the borehole 100, to be circulated to the surface where it is returned to the mud pit 160 through a mud return line 168.
A shaker screen (not shown) may be used to separate formation cuttings from the drilling mud before it returns to the mud pit 160. The MWD communication system 146 may utilize a mud pulse telemetry technique to communicate data from a downhole location to the surface while drilling operations take place. To receive data at the surface, a mud pulse transducer 170 is provided in communication with the mud supply line 166. This mud pulse transducer 170 generates electrical signals in response to pressure variations of the drilling mud in the mud supply line 166. These electrical signals are transmitted by a surface conductor 172 to a surface electronic processing system 180, which is conventionally a data processing system with a central processing unit for executing program instructions, and for responding to user commands entered through either a keyboard or a graphical pointing device. The mud pulse telemetry system is provided for communicating data to the surface concerning numerous downhole conditions sensed by well logging and measurement systems that are conventionally located within the MWD communication system 146. Mud pulses that define the data propagated to the surface are produced by equipment conventionally located within the MWD communication system 146. Such equipment typically comprises a pressure pulse generator operating under control of electronics contained in an instrument housing to allow drilling mud to vent through an orifice extending through the drill collar wall. Each time the pressure pulse generator causes such venting, a negative pressure pulse is transmitted to be received by the mud pulse transducer 170. An alternative conventional arrangement generates and transmits positive pressure pulses.
A plurality of gage inserts 235 is provided on the gage pad surfaces 230 of the drill bit 200. Shear cutting gage inserts 235 on the gage pad surfaces 230 of the drill bit 200 provide the ability to actively shear formation material at the sidewall of the borehole 100 and to provide improved gage-holding ability in earth-boring bits of the fixed cutter variety. The drill bit 200 is illustrated as a PDC (“polycrystalline diamond compact”) bit, but the gage inserts 235 of the same or other structure may be equally useful in other fixed cutter or drag bits that include gage pad surfaces 230 for engagement with the sidewall of the borehole 100.
As used herein, the term “drill bit” includes and encompasses any and all rotary bits, including core bits, roller cone bits, fixed cutter bits; including PDC, natural diamond, thermally stable produced (TSP) synthetic diamond, and diamond impregnated bits without limitation, as well as hybrid bits including fixed as well as rotatable cutting structures, eccentric bits, bicenter bits, reamers, reamer wings, and other earth-boring tools configured for acceptance of an electronics module 290 (
The end-cap 270 includes a cap bore 276 formed therethrough, such that the drilling mud may flow through the end-cap 270, through the central bore 280 of the shank 210 to the other side of the shank 210, and then into the body of drill bit 200. In addition, the end-cap 270 includes a first flange 271 including a first sealing ring 272, near the lower end of the end-cap 270, and a second flange 273 including a second sealing ring 274, near the upper end of the end-cap 270.
When a drill bit 200 having an end-cap 270 carrying an electronics module 290 needs to be repaired, before any repair process for the drill bit 200 is undertaken, the end-cap 270 having electronics module 290 therein should be removed from the drill bit 200 to ensure that the electronic module 290 will not be damaged.
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If the end-cap 270 with end-cap body configuration 400 is not, however removed, the configuration thereof prevents the drill bit 200 from being placed on the spindle 300. The annular end- cap body 400 includes an exterior surface 402, a bore segment 404 extending through a portion of the interior of the cap 400, a second bore segment 406 extending through a second portion of the interior of the cap 400, and one or more lugs 408 located on the second bore 406 at any desired position thereon so that the lugs 408 extend a predetermined distance radially into the second bore segment 406 of the cap 400. The lugs 408 are generally located in positions opposed from each other around the second bore 406. However, the lugs 408 may be located adjacent each other on the second bore 406. The lugs 408 located on the second bore 406 of the end-cap body 400 extend radially into the interior of the end-cap body 400 a predetermined distance such that the lugs 408 extend into the bore 276 of end-cap body 400 when an end-cap 270 located in the shank 210 of the drill bit 200. When a drill bit 200 has an end-cap 270 with an end-cap body 400 located in the shank 210 thereof with lugs 408 extending into the bore segment 406 of the end-cap 270 installed in the shank 210 of the drill bit 200, the lugs 408 interferingly engage a cylindrical annular segment 312, 310, 308, 306, 304, 302 sized for the particular shank 210 to prevent the drill bit 200 from being securely and correctly situated and seated about the respective cylindrical annular segment 302, 304, 306, 308, 310 and 312 of the spindle 300. In this manner, the lugs 408 of the end-cap body 400 identify a drill bit 200 having an end-cap 270 therein having an electronic module 290 (
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While the present invention has been described herein with respect to certain embodiments, those of ordinary skill in the art will recognize and appreciate that it is not so limited. Rather, many additions, deletions, and modifications to the described embodiments may be made without departing from the scope of the invention as hereinafter claimed, including legal equivalents. In addition, features from one embodiment may be combined with features of another embodiment while still being encompassed within the scope of the invention as contemplated by the inventors.