Drill string buried isolation housing and method in MWD system

Abstract

The housing defines a through passage along the length of the housing and is configured to support a set of electrical insulators around the through passage to form an electrically isolated break in the drill string, such that each of the set of insulators is subjected to a force not exceeding a compressive force in response to extension and contraction of the drill string. The housing defines a housing cavity for receiving an electronic package having a signal port, and the housing is configured to electrically connect the signal port across the electrically isolated break. To enhance the transmission of the locating signal, the housing cover can cooperate with the main housing body to define an elongated wire slot. The housing device can support an electrical connection from the electronic package so that the electronic package spans the electrically isolated gap.

Description

[0001] This application is a divisional application of the patent application with application number 2014800150492, application date March 10, 2014, and invention name “Drill String Buried Isolation Shell and Method in MWD System”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application is related to and claims the benefit of U.S. Nonprovisional Application No. 13 / 827,945, the entire contents of which are incorporated herein by reference. Technical Field

[0004] The present application relates generally to inground operations and, more particularly, to apparatus and methods for electrically coupling an electrical signal to a conductive drill string for transmitting the signal. Background Art

[0005] Typically, underground operations such as drilling to form a borehole for installation of utility lines, borehole surveys, etc., and subsequent expansion of the borehole, use a conductive drill string extending from an above-ground drilling rig. Prior art includes examples of using a conductive drill string as an electrical conductor for electrically transmitting data signals from an underground tool to a drilling rig. To detect the signal at the drilling rig, the ground surrounding the drilling rig is used as a signal return path. This type of system is often referred to as a measurement while drilling ("MWD") system.

[0006] For example, an attempt to use the drill string as an electrical conductor in an MWD system can be seen in U.S. Patent No. 4,864,293 (hereinafter the '293 patent). In one embodiment, the patent teaches an electrical isolation collar that is assembled around the drill string. The applicant of the present invention has recognized that in extremely harsh underground environments, such an electrical isolation collar ( Figure 2 , item 32) is problematic at least in terms of durability. Figure 3 and Figure 4In another embodiment shown in , a suitable dielectric separator 40 is schematically shown and stated to be used to electrically isolate the front part of the drill string from the rest of the drill string. No details are provided to properly teach the reader how to make the separator, but it is reasonable to imagine that the insulator is simply inserted into the disconnected part of the drill string so as to rotate with the drill string. Unfortunately, during drilling operations, the insulator will be subject to the same severe mechanical stresses as the drill pipe section of the drill string, including pure tension during pull-back operations and high shear forces caused by the rotational torque applied by the drilling rig on the drill string. Although the drill string is usually made of high-strength steel that can easily withstand these forces, the applicant is not aware of any currently available non-conductive material that can withstand all of these different forces with a reliability that the applicant considers acceptable. It will be recognized that the consequences of the end of the drill string breaking off during drilling operations are extremely serious. Therefore, the risk associated with using an insulator in the manner proposed is considered unacceptable.

[0007] An even earlier approach can be seen in U.S. Patent No. 4,348,672, in which an attempt was made to introduce an electrically isolated break in the drill string using various layers of dielectric material sandwiched between what the patent calls an "insulating gap subassembly" consisting of a first annular subassembly and a second annular subassembly. Figure 5 and Figure 6 An embodiment is shown, and the patent Figure 7 and Figure 8 Another embodiment is shown. Unfortunately, sandwiching relatively thin dielectric layers in gaps defined between adjacent high strength metal components (which can withstand extreme forces and harsh downhole environments) is unlikely to provide acceptable performance levels. Specifically, these dielectric layers are subject to the same harsh forces as the first and second annular subcomponents, and thus, durability is likely to be limited in harsh downhole environments. That is, when one of the relatively thin dielectric layers is worn through, the desired electrical isolation is compromised.

[0008] For example, practical methods for coupling electrical signals to a drill string in the context of an MWD system can be found in U.S. Patent Application No. 13 / 035,774 (hereinafter the '774 application), U.S. Patent Application No. 13 / 035,833 (hereinafter the '833 application), and U.S. Patent Application No. 13 / 593,439 (hereinafter the '439 application), all of which are owned by the same applicant as the present application and are incorporated herein by reference in their entirety. Although the '774 application, the '833 application, and the '439 application provided significant advantages over the then existing state of the art, the applicant has discovered other more advantageous methods, which are described below.

[0009] The foregoing examples of the prior art and their related limitations are intended to be illustrative, not exclusive. Other limitations of the prior art will become more apparent to those skilled in the art upon reading this specification and studying the accompanying drawings. Summary of the invention

[0010] The following embodiments and their various aspects are described and illustrated in conjunction with systems, tools and methods for providing examples and illustrations, not for limiting the scope. In various embodiments, one or more of the above problems have been mitigated or eliminated, while other embodiments involve other differences.

[0011] Generally, an apparatus and associated method are disclosed for use in combination with a drill string that is electrically conductive and extends from an inground end including an inground tool to a drill rig. In one aspect of the invention, a housing defines a through passage along the length of the housing, and the housing is configured to support an electrical insulator around the through passage to form an electrically isolated break in the drill string such that each of a set of electrical insulators is subjected to a force not exceeding a compressive force in response to the drill rig pushing the drill string and in response to the drill rig pulling the drill string. The housing defines a housing cavity for receiving an electronic package having a signal port, and is configured to electrically connect the signal port across the electrically isolated break.

[0012] In another aspect of the present invention, a housing device for use as part of an inground tool and an associated method are disclosed, the housing device housing a transmitter for transmitting a locating signal from the inground tool. The main housing supports the transmitter in an operating position while the transmitter transmits the locating signal. The cover is configured to be removably mounted on the housing so that at least a portion of the main housing and at least a portion of the cover are arranged in a facing relationship to jointly define at least one elongated wireway leading from an exterior of the housing device to the transmitter.

[0013] In another aspect of the present invention, a housing and related methods for use as part of an inground tool are disclosed, the housing supporting an electronic package having an output cable for carrying an output signal. The housing body is conductive and defines a cavity for receiving the electronic package, so that the electronic package forms a first electrical connection portion electrically connected to the housing body. An intermediate housing is conductive and received on one end of the housing body so that the intermediate housing cooperates with the housing body in a manner that forms an electrically isolated gap between the intermediate housing and the housing body while supporting the cable, so that the cable extends across the gap to be electrically connected to the intermediate housing, so that the electronic package electrically spans the gap. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Exemplary embodiments are illustrated in the drawings to which reference is made.The embodiments and drawings disclosed herein are intended to be illustrative rather than restrictive.

[0015] Figure 1 is a schematic elevation view of a system utilizing an embodiment of the buried isolation housing and associated methods of the present invention.

[0016] Figure 2 is a schematic perspective view showing an embodiment of the inground housing of the present invention in assembled form.

[0017] Figure 3 yes Figure 2 Schematic exploded perspective view of an embodiment of an inground housing.

[0018] Figure 4 yes Figure 2 Another schematic exploded perspective view of an embodiment of an inground housing.

[0019] Figure 5 yes Figure 2 A schematic partially cut-away assembly elevation view of an embodiment of an in-ground isolation housing is provided to illustrate the various components of the housing in assembled relationship.

[0020] Figure 6 yes Figure 2 Schematic and further enlarged cutaway elevation view of a portion of an embodiment of an insulator to further illustrate details of the structure of the insulator.

[0021] Figure 7 It further shows Figure 2 Schematic exploded perspective view of an embodiment of an inground housing and details of associated electronic packaging.

[0022] Figure 8 is a block diagram of an embodiment of a downhole electronics package suitable for use with embodiments of the buried isolation housing of the present invention.

[0023] Fig. 9 is a block diagram of an embodiment of an uphole electronics portion suitable for use on a drilling rig to bidirectionally communicate with a downhole electronics portion via the buried isolation housing of the present invention, and Fig. 9 Also included is an inset view showing a repeater embodiment and associated electrical connections that can convert the electronics portion for downhole repeater use.

[0024] Fig.10 is a schematic perspective view showing another embodiment of the inground housing of the present invention in assembled form.

[0025] Fig.11 It further shows Fig.10 Schematic partially cutaway exploded perspective view of a detail of an embodiment of an inground housing.

[0026] Fig.12 It is shown that the formation Fig.11 Schematic bottom perspective view of a detail of a cover portion of a portion of an embodiment. DETAILED DESCRIPTION

[0027] The following description is provided to enable one of ordinary skill in the art to make and use the invention, and is provided in the context of patent applications and their requirements. Various modifications to the described embodiments will be apparent to those skilled in the art, and the general principles taught in the specification may be applied to other embodiments. Therefore, the present invention is not intended to be limited to the embodiments shown, but rather to the widest scope consistent with the principles and features taught in the specification, including variations and equivalents, as defined by the scope of the appended claims. It should be noted that the drawings are not drawn to scale, but are naturally illustrated in a manner that best illustrates the features of interest. Descriptive terminology may be used with respect to these descriptions, however, such terminology is employed to facilitate the reader's understanding and is not intended to be limiting.

[0028] Turning now to the drawings, wherein like parts are designated by like reference numerals throughout the several views, attention will then be directed to Figure 1 , Figure 1 1 is a front elevational view schematically illustrating an embodiment of a horizontal directional drilling system, generally designated 10, and made in accordance with the present invention. While the illustrated system illustrates the present invention within the framework of a horizontal directional drilling system and components thereof for performing in-ground drilling operations, the present invention enjoys equal applicability with respect to other operating procedures including, but not limited to, vertical drilling operations, pullback operations for installing utilities, survey operations, and the like.

[0029] Figure 1 The system 10 is shown operating in an area 12. The system 10 includes a drilling rig 14 having a drill string 16 extending from the drilling rig 14 to an inground tool 20. The drill string can be pushed into the ground to move the inground tool 20 at least generally in the advancing direction 22 shown by the arrow. Although the present example is constructed and discussed in terms of using a drilling tool as an inground tool, it should be recognized that the discussion is also applicable to any suitable form of inground tool, including but not limited to reaming tools, tension monitoring tools used during pullback operations where utilities or housings can be installed, and survey tools such as using an inertial guidance unit and downhole pressure monitoring to survey the borehole path. In addition, the teachings of this article can be used with an isolation segment or inground housing that can be inserted into the drill string at any desired joint, including immediately behind the inground end of the drill string. In the operation of the drilling tool, monitoring is generally required based on the advancement of the drill string, while in other operations such as pullback operations, monitoring can be performed in response to the retraction of the drill string.

[0030] Continue to refer Figure 1 , the drill string 16 is partially shown and segmented, the drill string 16 is composed of a plurality of detachably attached individual drill pipe segments, some of which are denoted by 1, 2, n-1, and n, and the drill pipe segments have segment lengths or section lengths and wall thicknesses. The drill pipe segments may be interchangeably referred to as drill rods having rod lengths. During operation of the drilling rig, one drill pipe segment may be added to the drill string at a time and the drill pipe segments may be pushed into the ground with the aid of the drilling rig using a movable carriage 30 to advance the inground tool. The drill rig 14 may include a suitable monitoring device 32 for measuring the movement of the drill string into the ground, such as described in U.S. Patent No. 6,035,951 (hereinafter the '951 patent), entitled "SYSTEMSARRANGEMENTS AND ASSOCIATED METHODS FOR TRACKING AND / OR GUIDING ANUNDERGROUND BORING TOOL," which is owned by the same applicant as the present application and is incorporated herein by reference.

[0031] Each drill pipe segment defines a through opening 34 (one of which is shown) extending between opposite ends of the segment. The drill pipe segments may be equipped with features commonly referred to as male and female threaded fittings so that each end of a given drill pipe segment can be threadedly engaged with an adjacent end of another drill pipe segment in a drill string in a known manner. After the drill pipe segments are joined to form the drill string, the through openings of adjacent drill pipe segments align to form an integral passage 36 indicated by the arrows. The passage 36 may provide a pressurized flow of drilling fluid or mud in the direction of the arrows, which flows from the drilling rig to the drill bit or other inground tool, as will be further described.

[0032] The location of the drill in the area 12 and the underground path followed by the drill can be set and displayed at the drilling rig 14, for example, using a display 44 on a console 42. The console can include a processing device 46 and a control execution device 47. In some embodiments, the control and monitoring of operating parameters can be automated.

[0033] The drill tool 20 may include a drill bit 50 having an inclined surface for steering based on a rolling orientation. That is, when the drill bit is pushed forward without rotating, the drill bit will generally deflect based on the rolling orientation of the inclined surface of the drill bit. On the other hand, by rotating the drill string as shown by the double arrow 51 while pushing the drill bit, the drill bit can generally be made to move in a straight line. Of course, the foreseeable steering is premised on suitable soil conditions. It is worth noting that in order to cut into the earth directly in front of the drill bit and provide cooling and lubrication to the drill bit, the aforementioned drilling fluid can be ejected under high pressure. The drill tool 20 includes an underground housing 54 containing an electronic package 56. The underground housing is configured to allow the drilling fluid to flow around the electronic package to the drill bit 50. For example, the electronic package may include a cylindrical housing structure supported in the housing 54 in a centrally positioned manner. The drill bit 50 may include a male threaded fitting housed in a female threaded fitting of the underground housing 54. The opposite end of the underground housing may include a female threaded fitting that receives the male threaded fitting of the underground end of the drill string 16. For the discussion herein and the appended claims, the drill tool may be considered to be part of the drill string so as to define the underground end of the drill string. It is noteworthy that the female threaded fittings and male threaded fittings of the drill bit and the underground housing may be the same as the female threaded fittings and male threaded fittings provided on the drill pipe section of the drill string so that the drill pipe sections can be detachably connected to each other when forming the drill string. Of course, the fittings on the ends of the underground housing can be easily replaced to accommodate special needs. The underground electronic package 56 may include a drill string transceiver 64 and a positioning transceiver 65. Further details about the drill string transceiver will be provided at an appropriate location below. In some embodiments, the positioning transceiver 65 may send a ground-penetrating signal 66 such as a dipole positioning signal, and may receive electromagnetic signals generated by other underground components, which will be described at an appropriate location below. In other embodiments, the positioning transceiver 66 may be replaced by a transmitter or may not be required. In other embodiments, the transceiver 65 can be configured to receive a magnetic positioning signal sent from the ground so as to sense the magnetic field using a magnetometer, which will be described further. For ease of description, this example assumes that the electromagnetic signal 66 is a positioning signal in the form of a dipole signal. Therefore, the electromagnetic signal 66 can be referred to as a positioning signal. It should be understood that the electromagnetic positioning signal can be modulated like any other electromagnetic signal, and the modulation data can be recovered from the signal after modulation. The positioning function of the signal can depend at least in part on the characteristic shape and signal strength of the magnetic flux field and not on the ability of the signal to carry the modulated signal. Therefore, modulation is not required.Information about certain parameters of the drill tool, such as pitch and roll (orientation parameters), temperature, drilling fluid pressure, and annular pressure around the drill tool, can be measured using a suitable sensor device 68 located in the drill tool, which can include, for example, a pitch sensor, a roll sensor, a temperature sensor, an AC field sensor for sensing the vicinity of a 50 / 60 Hz utility line, any other sensors required, such as a DC magnetic field sensor for sensing yaw orientation (a three-axis magnetometer and / or magnetic positioning signal with a three-axis accelerometer to form an electronic compass used in conjunction with the magnetometer to measure yaw orientation), and one or more pressure sensors. The drill string transceiver 64 can include a processor required when connected to the sensor device 68 and the positioning transceiver 65. In some embodiments, one or more accelerometers can be used to measure orientation parameters such as pitch and roll orientation. A battery (not shown) can be provided in the housing to provide power.

[0034] A portable locator 80 may be used to detect the electromagnetic signal 66. A suitable and highly advanced portable locator is described in U.S. Pat. No. 6,496,008, entitled "FLUX PLANE LOCATING IN AN UNDERGROUND DRILLING SYSTEM", of the same applicant as the present application, the entire contents of which are incorporated herein by reference. Although the framework of a horizontal directional drill is used for ease of description, as mentioned above, the present description is applicable to a variety of underground tools and is not intended to be limiting. As discussed above, the electromagnetic signal 66 may carry information including orientation parameters such as pitch and roll. The electromagnetic signal may also carry other information. For example, such a signal may include parameters measured near or within the drill tool, including temperature, pressure, and voltages such as battery voltage or power supply voltage. The locator 80 includes an electronic package 82. It is noteworthy that the electronic package is connected to various components of the locator for electrical communication, and the electronic package 82 may perform data processing. The information of interest may be modulated on the electromagnetic signal 66 in any suitable manner and transmitted to the locator 80 and / or the antenna 84 at the drill rig, but this is not required. Any suitable form of modulation currently available or yet to be developed may be used. Examples of currently available and suitable types of modulation include amplitude modulation, frequency modulation, phase modulation, and variations thereof. While recovering any parameters of interest related to drilling, such as pitch, from the locating signal, these parameters of interest may be displayed on the display 44 and / or the display 86 of the locator 80. The locator 80 may transmit a telemetry signal 92. The drill rig 14 may transmit a telemetry signal 98 that can be received by the locator 80. The telemetry component provides a two-way signal between the drill rig and the locator 80. As an example of such a transmitted signal, based on the status provided by the drill rig monitoring unit 32, the drill tool may transmit an indication that the drill string is stationary because a drill pipe segment is being added to the drill string or a drill pipe segment is being removed from the drill string.

[0035] Still reference Figure 1, electrical connections 100a and 100b may extend from the buried electronic package 56, which will be further described. Via these electrical connections, any sensed value or parameter related to the operation of the buried tool can be electrically transmitted from the electronic package. It should be understood by those of ordinary skill in the art that a device commonly referred to as a "wire-in-pipe" can be used to transmit signals bidirectionally between a drilling rig and an buried tool, wherein one electrical connection includes an insulated conductor extending upward from the internal passage 36 of the drill string to the drilling rig, and another electrical connection is directly connected to the conductive drill string. The term wire-in-pipe refers to such a conductor that is typically housed in an internal passage. However, according to the present invention, electrical connections 100a and 100b are formed to span an electrically isolated gap 104 formed by the housing 54, which will be further described. It is noteworthy that these electrical connections can be collectively referred to as signal ports associated with the electronic package. In various embodiments, the signal port can be configured for unidirectional communication or bidirectional communication.

[0036] Now combine Figure 1 Turn your attention to Figure 2 . Figure 2 is a schematic perspective view of an embodiment of the housing 54 in its assembled form. The assembly includes a main housing 200, which may have a female threaded fitting 210 that receives the drill bit 50. The intermediate housing 220 may define a female threaded fitting 222. As discussed above, these fittings may match the corresponding fittings on the drill pipe section that makes up the drill string 16, so that the buried housing 54 can be inserted into any desired joint in the drill string. The buried housing is provided with an electrically isolating disconnect 104 between the main housing 200 and the intermediate housing 220. In some embodiments, a mud motor may be attached to the housing 54. In this embodiment, the opposite side of the mud motor may support a curved segment that itself supports the drill bit. The mud motor may rotate the curved segment in response to the pressure of the drilling fluid in a known manner without rotating the drill string.

[0037] Now combine Figure 2 Turn your attention to Figure 3 and Figure 4 . Figure 3 is a schematic exploded perspective view of the buried housing 54 as seen from the end of the female threaded fitting 210, and Figure 42 is a schematic exploded perspective view from the end of the female threaded fitting 222. It should be understood that the threads on the male threaded fittings and female threaded fittings and other components in the various figures are only schematically shown, but it should be understood that the threads exist and such threaded connections are known. The main housing 200 defines a cavity for receiving the electronic package 56. The cover 228 can be received by the main housing by first inserting the ear piece 232 and then fixing the cover 228 with the pin 236. First, the pin can be fixed to the cover by inserting the pin into the cover and passing through the fixing clip 240. The fixing clip can be received in the annular groove 238 so that when the cover is removed from the main housing 200, the pin can be kept together with the cover. The pin 236 is defined with an annular channel 242 with a reduced diameter so that the roll pin 244 can be inserted into the opening 246 defined by the main housing and received in the annular channel 242 to keep the cover 228 in the installed position, which will be seen in subsequent figures. After the cover is installed, the electronic package 56 is locked between the housing and the cover. Figure 1 To provide a positioning signal 66 and allow the pressure sensor of the electronic package to be subjected to pressure in an annular area around the drilled hole, a wire groove 248 may be defined by the cover portion and an additional wire groove 250 may be defined by the main housing 200 .

[0038] Still reference Figure 3 and Figure 4 The main housing extension 252 extends from the main housing 200 and may be formed integrally with the main housing 200. Figure 4As seen in the main housing extension, the main housing extension defines an access opening 256. The internal threads of the main housing extension are configured to receive the threaded end portion 260 of the main mounting bolt 264. When assembled, a plurality of preload bolts 268 can be used to apply preload pressure to the electrically insulating electrical insulator 272 in a manner to be described below. In other embodiments, a shaft can be used in place of the main mounting bolts. The free end of the shaft can be tapped to receive a nut that replaces the preload bolt 268. The nut can be adjusted to apply the preload force. Such a shaft can be integrally formed with the main housing 200 or configured to be threadedly engaged with the main housing extension 252. In this embodiment, the electrical insulator is a ceramic component. Although the ceramic component can have any suitable form, spherical ceramic insulators have been found to be more useful. Other suitable shapes will be discussed at appropriate locations below. The main housing, intermediate housing, cover, main assembly bolts and other suitable components can be generally formed of suitable high strength materials such as 4340, 4140, 4142 and 15-15HS or Monel K500 (where the latter two are non-magnetic high strength alloys) because these components are subject to potentially harsh downhole environments and relatively extreme force loads during underground operations. The selection of materials can be based, at least in part, on the performance characteristics of typical drill pipe sections. With the isolation disk 282 abutting the end face of the main housing extension, the spacing cylinder 278 is received on the main housing extension 252.

[0039] Now combine Figures 2 to 4 Turn your attention to Figure 5 and Figure 6 . Figure 5 is a schematic partially cutaway assembly elevation view of an inground housing 54 supporting an electronic package 56, and Figure 6 FIG. 2 is a further enlarged schematic partial cutaway assembly elevation view of a portion of one end portion 300 of the buried housing. Figure 5 and Figure 6 As seen in FIG. 1 , the intermediate housing 220 includes an inner flange 310. When the intermediate housing is mounted on the extension 252, the spacing cylinder 278 is disposed between the side wall of the extension and the inner side wall of the intermediate housing, and the isolation disk 282 is locked between one surface of the inner flange 310 and the end face of the extension. At the same time, the annular spacing disk 314 defines an opening having an outer diameter configured to receive the insulators 272, so that each insulator is partially received in a hemispherical (i.e., a portion of a spherical shape) groove 318 ( Figure 4 ) and is partially received in a hemispherical groove 326 ( Figure 3 The main assembly bolt 264 defines a channel 334 ( Figure 3 and Figure 4). After the split isolation sleeve 338 is in place, the main assembly bolts are installed to the threaded extension 252 via the first and second insulators or thrust rings 340 and 342, respectively. The outer surface of the split isolation sleeve 338 faces the inner surface of the flange 310. The outer isolation sleeve 350 is received to surround the head of the main assembly bolt and extend outward from the isolation rings 340 and 342 to the flange 310. With the main assembly bolts 264 installed, the preload bolts 268 can be torqued to apply a pre-compression load to the insulator 272. The preload force can be based on a number of factors including, but not limited to, the type of material forming the insulator, the shape of the insulator, and the expected loads to be encountered during inground operations. The preload force should be large enough so that the pulling force of the drilling rig, the bending force of the drill string, or any combination thereof will not cause one or more insulators to be removed. After the preload is applied, the input funnel 360 can be inserted into the fitting 222 so that the through opening 364 passes through the assembly to the through passage 368 defined by the main housing 200 and leads to the opposite female threaded fitting 210 so that the drilling fluid can pass through the assembly as a jet 52 ( Figure 1 ) is ejected from the drill bit 50 or reaches some other inground tool that requires fluid replenishment. The input funnel can be maintained in the installed position, for example, by means of an O-ring 370 received in a peripheral groove of the input funnel and a mating groove defined by the intermediate housing 220. Various electrical isolation components including the split insulating sleeve 338, the first thrust ring 340, the second isolation ring 342, the spacing cylinder 278, the isolation disk 282, the annular spacing disk 314, the outer insulating sleeve 350 and the input funnel 360 can be formed of any suitable material including but not limited to those listed below. The first thrust ring and the second thrust ring can be formed of, for example, TTZ (quadrilateral toughened zirconia). Each of the spacing cylinder 278, the isolation disk 282, the annular spacing disk 314 and the outer isolation sleeve 350 can be formed of, for example, PVC (polyvinyl chloride), PEEK (polyetheretherketone) or acetal. The input funnel 360 can be formed of, for example, UHMW (ultra-high molecular weight polyethylene) or rubber.

[0040] refer to Figures 5 to 7 , attention will now be turned to details regarding the mounting of the electronics package 56 and the manner in which the electrical connections are made between the electronics package and the housing components. Figure 7 is a schematic exploded perspective view showing the components and features of the main housing 200, the electronic package 56, and the associated electrical connections. Figure 7As best seen in FIG. 4 , the electronic package may include an elongated cylindrical body 400 having a first tail bumper 404 and a second tail bumper 408 disposed at each of the first and second ends of the body, respectively. An O-ring 310 may support the body in an intermediate position. The first end of the body 400 may support a conductive end cap 412 in electrical communication with, for example, a cathode power connector lead / terminal serving an internal circuit of the package. Notably, the end cap may serve as Figure 1 A cable 420 for bidirectionally transmitting information between the electronic package and the drilling rig extends from the first tail buffer 404, and the cable 420 includes an electrically insulating sheath surrounding a conductor 424. It is worth noting that the conductor 424 can be used to form Figure 1 For example, the index pin 428 may be press-fit to hold the tail bumper 404 in place on the end cap 412. The contact spring 432 may be received in a hole defined by the tail bumper 404 so that the contact spring 432 is electrically engaged with the end cap 412. The free end of the contact spring forms a partial electrical connection with the main housing 200, thereby completing the electronic package after final installation. Figure 1 However, prior to this final installation, the cable 420 extends through the hole 448 ( Figure 3 ) intersecting channel 444( Figure 6 ) so that the cable extends through the contact insulator 452 when the electronic package is in the installed position. It is worth noting that the channel 444 can be terminated by a plug 454 that can be threadedly received by the extension 252. The through pin 460, bias spring 464, cover 470 and O-ring 472 are installed through the aligned openings defined by the intermediate housing 220 and the spacing cylinder 278 so that the through pin contacts the cable 420 within the contact insulator 452. The cover 470 can be threadedly engaged with the intermediate housing 220 so that the conductive through pin pierces the jacket of the cable and forms an electrical connection with the conductor 424 by tightening the cover. The spring 464 is in electrical contact with the through pin, and the through pin itself is in electrical contact with the cover 470. Because the cover 470 is in electrical contact with the intermediate housing 220, the electrical connection between the intermediate housing and the conductor 424 is formed to complete the electrical connection. Figure 1 The electrical connection 100a allows the electrical signals carried by the cable to be connected to the intermediate housing and thus to the conductive drill string of the guiding drill, or conversely, the signals from the drill on the drill string can be connected to the cable and thus to the electronic package.

[0041] Having described the structure of the inground housing 54 in detail above, attention will now be directed to details related to the operational aspects of the inground housing 54. During installation, the preload bolts 268 may be torqued to a significantly large value, such as 2,500 foot-pounds, to apply pressure to the insulators 272, thereby applying a pre-compression load to all of the insulators. That is, the pre-compression load attempts to stretch the main assembly bolts 264 in response to the compression of the insulators between the main housing 200 and the intermediate housing 220. The amount of pressure on individual ones of the electrical insulators may be based on the amount of retraction and / or insertion forces (thrust and / or pull) that any given drilling rig is capable of generating. With 12,000 pound-feet of torque applied by the drilling rig, the present embodiment is capable of withstanding 100,000 pound-feet of thrust or retraction forces.

[0042] refer to Figure 6 , with the thrust 500 indicated by the arrow. When the intermediate housing 220 receives this thrust / extension force from the uphole portion of the drill string, the intermediate housing directly transmits the thrust to the main housing 200 through the insulator 272. The insulator is subjected to only an increase in compression force in addition to the preload compression force in response to the thrust. In contrast, when the intermediate housing receives a tensile / contraction force from the drill string, the internal flange 310 moves toward the head of the main assembly bolt 264 to apply a contraction force to the head of the main assembly bolt via the isolation rings 340 and 342 and the preload bolt 268. The main assembly bolt, in turn, directly applies a contraction force to the extension 252 of the main housing 200, causing the main housing to be pulled in response to the contraction force. In addition, the insulator is subjected to only an increase in compression force in response to the contraction force.

[0043] It should be understood that the insulator 272 can be subjected to very high compressive loads during the underground operation, but the insulator is only subjected to the compressive force generated in response to the extension and / or contraction of the drill string by the drill rig. The insulator is subjected to bending loads only in response to the rotation of the drill string. However, in this regard, the applicant has found that this bending load is significantly less than the compression load. That is, in order to withstand this compression, suitable materials are required. Suitable materials may include ceramic materials that are now available or yet to be developed. As a non-limiting example, suitable materials include silicon nitride and phase-transformation toughened zirconium oxide. Experimental tests conducted by the applicant have shown that the arrangement of only three spherical silicon nitride electrical insulators can withstand 3 times the rated torque of a typical drill pipe section. In other embodiments, the insulator 272 may include an outer peripheral profile other than a spherical shape. In such embodiments, the grooves of the locking electrical insulator may include complementary shapes. As a non-limiting example, other suitable shapes may include various geometric shapes, including but not limited to elongated shapes such as cylinders or regular quadrangular prisms. In addition, the layout and / or overall number of electrical insulators may be changed in any suitable manner. For the layout, for example, concentric rings of electrical insulators may be provided.

[0044] Figure 8 is a block diagram illustrating an embodiment of an electronic package 56 in further detail. The electronic package may include a Figure 1 The inground housing 54 is schematically shown as forming an electrically isolating disconnect 104, thereby separating an uphole portion 527a of the drill string from a downhole portion 527b of the drill string for use in one or both of a transmit mode and a receive mode, in which data is coupled to the drill string, and in which data is recovered from the drill string. The downhole portion 527b may include a drill bit or any other suitable type of buried tool, such as a reaming tool used in a pullback operation in conjunction with a tension monitoring device or a survey tool. In some cases, the downhole portion may include one or more drill pipe segments or other buried segments between the buried housing 54 and the buried tool. The electronic portion is connected via a first lead 528a and a second lead 528b (which may be collectively represented by the reference numeral 528) across an electrically insulating / isolating disconnect formed by an insulator. For the transmit mode, an antenna driver portion 530 electrically connected between the buried digital signal processor 510 and the lead 528 is used to directly drive the drill string. Typically, data that can be coupled into the drill string can be used in conjunction with a signal 66 ( Figure 1 ) to avoid interference. When antenna driver 530 is off, on / off switch (SW) 550 can selectively connect lead 528 to a bandpass filter (BPF) 552 having a center frequency corresponding to the center frequency of the data signal received from the drill string. BPF 552 is in turn connected to analog-to-digital converter (ADC) 554, which is itself connected to digital signal processing section 510. From the perspective of the particular form of modulation used, one of ordinary skill in the art can readily construct the recovery of the modulated data in the digital signal processing section.

[0045] Still reference Figure 8, the dipole antenna 540 can be connected for use in one or both of a transmit mode and a receive mode, in which the signal 66 is transmitted into the surrounding ground, and in which an electromagnetic signal, such as a signal from an in-ground tension monitoring tool, can be received. For the transmit mode, the antenna is driven using an antenna driver portion 560 electrically connected between the in-ground digital signal processor 510 and the dipole antenna 540. In addition, the frequency of the signal 66 is typically completely different from the frequency of the drill string signal to avoid interference between the signal 66 and the drill string signal. When the antenna driver 560 is turned off, an on / off switch (SW) 570 can selectively connect the dipole antenna 540 to a bandpass filter (BPF) 572 having a center frequency corresponding to the center frequency of the data signal received from the dipole antenna. The BPF 572 is in turn connected to an analog-to-digital converter (ADC) 574, which itself is connected to the digital signal processing portion 510. In view of the specific form or forms of modulation employed, and in view of the overall disclosure of the present invention, a person of ordinary skill in the art will be able to readily construct transceiver electronics for the digital signal processing portion in many suitable embodiments. In view of the teachings disclosed herein, the transceiver electronics may be modified in any suitable manner. Figure 8 Design shown.

[0046] refer to Figure 1 and Fig. 9 , Fig. 9 1 is a block diagram of components that may constitute one embodiment of an above ground transceiver apparatus (generally indicated by reference numeral 600) that is coupled to a drill string 16. An above ground current transformer 602 is positioned, for example, on a drill rig 14 to couple and / or receive signals from the drill string 16. The current transformer 602 may be electrically connected for use in one or both of a transmit mode in which data is modulated on the drill string and a receive mode in which the modulated data is recovered from the drill string. A transceiver electronics package 606 is connected to the current transformer and may be powered by the drill rig. For the transmit mode, the current transformer is driven using an antenna driver portion 610 electrically connected between an above ground digital signal processor 620 and the current transformer 602. The data that can be coupled into the drill string may be driven using the antenna driver portion 610 electrically connected between an above ground digital signal processor 620 and the current transformer 602. The data that can be coupled into the drill string may be driven using the antenna driver portion 610 electrically connected to the above ground digital signal processor 620 and the current transformer 602. Figure 1 ) is modulated at a different frequency from the dipole antenna 540 to avoid interference and to distinguish it from the buried shell 54 ( Figure 8) drives the frequency of the signal on the inground end of the drill string. When the antenna driver 610 is off, an on / off switch (SW) 620 is capable of selectively connecting the current transformer 602 to a bandpass filter (BPF) 622 having a center frequency corresponding to the center frequency of the data signal received from the drill string. The BPF 622 is in turn connected to an analog-to-digital converter (ADC) 630, which is itself connected to a digital signal processing portion 632. It should be understood that the digital signal processing portion 632 and related components can form part of the processing device 46 of the drilling rig (shown using dashed lines) or be connected to the processing device 46 on a suitable interface 634. The transceiver 606 can send commands to the inground tool for various purposes, such as controlling the transmission power, selecting the modulation frequency, changing the data format (e.g., reducing the baud rate to increase the decoding range), etc. Depending on the particular form or forms of modulation employed, and in view of the overall disclosure of the present invention, one of ordinary skill in the art will be able to readily construct transceiver electronics for the digital signal processing portion in a number of suitable embodiments.

[0047] Still reference Figure 1 and Fig. 9 In a repeater embodiment, another in-ground isolator device 640 (shown in a dashed box) may be used in place of the current transformer 602 along with another instance of the in-ground housing 54. The device 640 may include any suitable embodiment of the in-ground housing. In this device, the in-ground housing 54 supports the transceiver 606 and is inserted as a unit into a joint of the drill string to serve as a repeater 1000 feet (for example) away from the in-ground tool. Thus, the portion 527a' of the drill string may connect the repeater to the drill rig, while the portion 527b' of the drill string serves as the middle portion of the drill string leading to the in-ground housing 54 at the in-ground tool. The repeater unit may, for example, be inserted into a joint formed in the in-ground housing 54. Figure 1 In the joint between drill pipe section 1 and drill pipe section 2 in the drill pipe section. The buried housing for repeater applications may include a female threaded fitting at one end and a male threaded fitting at the opposite end. Of course, those of ordinary skill in the art will recognize that adapters of the male and female threaded fitting type are known and readily available. To avoid signal interference, and as a non-limiting example, the repeater can acquire a signal originating from an underground tool or another repeater at one carrier frequency, and the repeater electronics can resend the signal upward along the drill string at different carrier frequencies to distinguish the signals from each other. As another example, suitable modulation can be used to distinguish the signals. Therefore, the repeater electronics package can be housed in any suitable manner and the repeater electronics package can be electrically communicated with the signal coupling device of the insulator to generate a repeater signal that is distinguishable from the received data signal based on the received data signal.

[0048] Now turn your attention to Figures 10 to 12 . Fig.10 1 is a schematic perspective assembly view showing another embodiment of the underground housing of the present invention, which is generally indicated by reference numeral 54 ′. Fig.11 is a schematic partial exploded view of the housing 54 ′. It should be noted that the housing 54 ′ shares features with the aforementioned housing 54 , and for the sake of brevity, the description of the same features and components will not be repeated. Fig.12 2 is a schematic perspective view of the modified cover 228' as viewed from below. The cover 228' also defines a wire slot 244, however, the cover extends outward at least substantially in the area of ​​the wire slot 244. In this way, opposite extensions 700 are formed, each of which includes a longitudinal edge 706 as part of the peripheral edge structure of the cover. Each extension is defined by a surface 708. The cover defines a cover cavity 710, which at least partially accommodates the electronic package 56 when the cover is installed. At the same time, the modified main housing 200' defines a support groove 712 that can be formed in the bottom plate 714 so that the support groove accommodates the electronic package 56. An outer edge 720 is formed at the intersection of the periphery of the bottom plate 714 and the cylindrical structure of the main housing 200'. When the cover 228' is mounted on the main housing 200', a wire groove 730 (one of which is visible) is defined between each cover surface 708 and the bottom plate 714 in a facing relationship, so that each longitudinal edge 706 is in a facing relationship with one of the outer edges 720 at the entrance of each wire groove 730. The wire groove 730 functions in the same manner as the wire groove 250 described above to enhance the transmission of the positioning signal by limiting the eddy current that may otherwise flow between the cover and the main housing. The wire groove 730 can have any suitable width, including a width that is just enough to prevent the flow of eddy currents. Although the wire groove 730 is shown as being in a linear or straight configuration, it should be understood that this is not a requirement. In some embodiments, the wire groove end can further extend at least a portion of the curved facing relationship between the main housing and the cover. In this regard, the applicant has recognized that it is not easy to cut a wire groove or groove in thicker high-strength steel, and this may significantly increase the overall cost of producing the buried housing.

[0049] refer to Fig.11 and Fig.12 , the modified pin 236' can be fixedly attached to the cover 228', for example, by welding. The pin 236' can be formed in any suitable manner, including being integrally formed with the cover. In this embodiment, the pin 236' defines a through hole 736 for receiving the roll pin 244 after the cover is installed on the housing. After the cover is installed, the electronic package 56 is locked between the housing and the cover.

[0050] The foregoing description is not intended to be limiting as to the specific form and / or features of the inground housing used to form an electrically isolated break or gap in a drill string. In this regard, any suitable modification for forming an electrically isolated drill string gap is deemed to be within the scope of the present invention, provided that the teachings disclosed herein are implemented. Thus, the present invention provides embodiments of such inground housings: any of its various forms facilitate communication using the drill string as an electrical conductor while maintaining robust mechanical properties that meet or even exceed the mechanical properties of the drill rods themselves that make up the drill string. The present invention proposes such inground housings, related components and methods that have not been seen heretofore. The present invention eliminates the limitations of the following prior art: the prior art that attempts to provide an electrically isolated break in a drill string by introducing an essentially fragile annular connector formed of an electrical insulator but still subjected to the full working load; or the prior art that attempts to use relatively thin layers of insulating / dielectric material that are damaged by wear through.

[0051] The above description of the present invention is provided for the purpose of explanation and illustration. For example, in another embodiment, the buried electronic package and the buried housing can be configured to receive positioning signals instead of sending positioning signals. In this embodiment, the positioning signal can be a magnetic dipole field emitted by rotating a permanent magnet around an axis of rotation, which is perpendicular to an axis extending between the north pole and the south pole of the magnet. A magnetometer can be used to receive the rotating magnetic field, and the magnetometer is used as a sensor forming a part of the electronic package. In order to receive the magnetic signal, the buried housing and related components of the present invention can be formed of non-magnetic materials. In addition, for this embodiment, there is no need to form a wire groove in the housing and the housing cover. For example, such a system is described in detail in U.S. Patent No. 7,775,301, which belongs to the same applicant as the present application and is incorporated herein by reference. Therefore, the present invention is not intended to be exhaustive or limit the present invention to the exact form disclosed, and other embodiments, modifications and variations can be made in view of the above teachings, wherein those skilled in the art can recognize certain modifications, substitutions, additions and sub-combinations of these teachings.

[0052] All elements, parts and steps described herein are preferably included. It should be understood that any of these elements, parts and steps can be replaced by other elements, parts and steps or completely deleted, as will be apparent to those skilled in the art.

[0053] In general, at least the following is disclosed herein. A housing defines a through passage along the length of the housing and is configured to support a set of electrical insulators around the through passage to form an electrically isolated disconnect portion in a drill string, such that each of the set of insulators is subjected to only forces not exceeding a compressive force in response to extension and contraction of the drill string. The housing defines a housing cavity for receiving an electronic package having a signal port, and the housing is configured to electrically connect the signal port across the electrically isolated disconnect portion. To enhance the transmission of the positioning signal, the housing cover can cooperate with the main housing body to define an elongated wire slot. The housing device can support an electrical connection portion from the electronic package so that the electrical connection portion crosses the electrically isolated gap.

[0054] Conception

[0055] This document also discloses at least the following concepts.

[0056] Concept 1. An apparatus for use in combination with a drill string, the drill string being electrically conductive and extending from an inground end including an inground tool to a drilling rig, the apparatus comprising:

[0057] a set of electrical insulators; and

[0058] a housing defining a through passage along the length of the housing, and the housing being configured to support the electrical insulators around the through passage to form an electrically isolated break in the drill string, such that in response to the drill rig pushing the drill string and in response to the drill rig pulling the drill string, each of the set of electrical insulators is subjected to a force not exceeding a compressive force, and the housing defining a housing cavity for receiving an electronic package having a signal port and being configured to electrically connect the signal port across the electrically isolated break.

[0059] Concept 2. The device of concept 1, wherein the device is configured to be inserted into the drill string so as to then form a portion of the overall length of the drill string.

[0060] Concept 3. The device of Concept 1 or Concept 2, wherein the device is configured to form a part of the inground tool.

[0061] Concept 4. The device according to any one of Concepts 1 to 3, wherein the electrical insulator is formed of a ceramic material.

[0062] Concept 5. The device according to Concept 4, wherein the ceramic material is selected from at least one of toughened zirconium oxide and silicon nitride ceramics.

[0063] Concept 6. The device according to any one of Concepts 1 to 5, wherein each of the electrical insulators is solid.

[0064] Concept 7. The device according to any one of Concepts 1 to 5, wherein each of the electrical insulators has a spherical configuration.

[0065] Concept 8. The device according to any one of Concepts 1 to 7, wherein the electrical insulator is locked by the housing around a center line of the housing.

[0066] Concept 9. The device according to any one of Concepts 1 to 8, wherein the housing supports twelve of the electrical insulators.

[0067] Concept 10. The device according to any one of Concepts 1 to 9, wherein the compressive force is applied to opposite side edges of the spherical outer surface of each of the electrical insulators.

[0068] Concept 11. The device according to any one of Concepts 1 to 9, wherein the housing comprises an intermediate housing configured to engage with the main housing such that the electrical insulator is locked between the main housing and the intermediate housing.

[0069] Concept 12. A device according to Concept 11, wherein the intermediate shell includes opposite first and second ends, such that the second end defines a peripheral end wall, and the main shell includes opposite main shell first ends and main shell second ends, such that the main shell first end defines a peripheral side edge, and the peripheral side edge is arranged to be in a facing relationship with the peripheral end wall of the intermediate shell to jointly define a plurality of recesses, such that each recess locks one of the electrical insulators.

[0070] Concept 13. An apparatus according to Concept 11 or Concept 12, wherein the intermediate housing defines an internal passage for rotatably receiving an extension of the main housing, and the extension defines a hole for detachably receiving a main assembly bolt in electrical contact with the main housing, so that the main assembly bolt applies a preload compression force to the electrical insulator.

[0071] Concept 14. A housing device for use as part of an inground tool, the housing device housing a transmitter for transmitting a positioning signal from the inground tool, the housing device comprising:

[0072] a main housing for supporting the transmitter in an operating position while the transmitter transmits the locating signal; and

[0073] A cover portion is configured to be removably mounted on the housing so that at least a portion of the main housing and at least a portion of the cover portion are arranged in a facing relationship to jointly define at least one elongated wire slot leading from the exterior of the housing device to the transmitter.

[0074] Concept 15. The housing device according to Concept 14, wherein the main housing and the cover cooperate with each other to define a pair of opposing elongated wire grooves.

[0075] Concept 16. The housing device according to Concept 15, wherein the cover defines a cover wire groove in the pair of opposing elongated wire grooves.

[0076] Concept 17. The housing device according to any one of Concepts 14 to 16, wherein the main housing includes an elongated axis, and the wire groove is at least substantially parallel to the elongated axis.

[0077] Concept 18. A housing for use as part of an inground tool, the housing being used to support an electronic package having an output cable, the output cable being used to carry an output signal, the housing comprising:

[0078] a housing body which is conductive and defines a cavity for receiving the electronic package, so that the electronic package forms a first electrical connection portion electrically connected to the housing body; and

[0079] An intermediate shell is conductive and can be received on one end of the shell body, so that the intermediate shell cooperates with the shell body in a manner of forming an electrical isolation gap between the intermediate shell and the shell body while supporting the cable, so that the cable extends across the gap and is electrically connected to the intermediate shell, so that the electronic package electrically spans the gap.

[0080] Concept 19. The device according to Concept 1, further configured as follows:

[0081] The device is a part of the underground tool, and the electronic package is housed in the shell. The electronic package is used as a transmitter to send a positioning signal from the underground tool. The device includes a cover portion, which is configured to be detachably mounted on the shell, so that at least a portion of the main shell and at least a portion of the cover portion are arranged in a facing relationship to jointly define at least one elongated wire groove leading from the outside of the shell device to the transmitter.

[0082] Concept 20. The device of Concept 11, wherein the electronic package includes an output cable used as a signal port, the output cable is used to carry an output signal, and the housing further includes:

[0083] a housing body which is conductive and defines the housing cavity for receiving the electronic package, so that the electronic package forms a first electrical connection portion electrically connected to the housing body; and

[0084] An intermediate shell is conductive and can be received on one end of the shell body, so that the intermediate shell cooperates with the shell body in a manner of forming an electrical isolation gap between the intermediate shell and the shell body while supporting the cable, so that the cable extends across the gap and is electrically connected to the intermediate shell, so that the electronic package electrically spans the gap.

[0085] Concept 21. The device of Concept 1, wherein each electrical insulator in the second set of electrical insulators comprises a same outer peripheral profile, and the housing captures a plurality of components of the second set of electrical insulators at evenly spaced locations about a centerline of the housing.

[0086] Concept 22. The device of Concept 21, wherein each electrical insulator of the second set of electrical insulators has a spherical configuration.

[0087] Concept 23. The device of Concept 22, wherein each spherical component is formed to be solid.

Claims

1. A housing device used as a part of an underground tool, the housing device receiving a transmitter for sending a positioning signal from the underground tool, the housing device comprising: a main housing for supporting the transmitter in an operating position while the transmitter transmits the positioning signal; as well as a cover portion configured to be removably mounted on the housing so that at least a portion of the main housing and at least a portion of the cover portion are arranged in a facing relationship to jointly define at least one elongated wire slot leading from an exterior of the housing device to the transmitter, wherein the transmitter is received in the housing; Wherein, the shell includes an intermediate shell, the intermediate shell defines an internal channel for rotatably receiving an extension portion of the main shell, and the extension portion defines a hole, the hole is used to detachably receive a main assembly bolt that is in electrical contact with the main shell, so that the main assembly bolt applies a compressive preload to the insulator.

2. The housing device according to claim 1, wherein: The main housing and the cover cooperate with each other to define a pair of opposing elongated wire grooves, each of which leads from the outside of the housing to the transmitter, wherein the transmitter is received in the housing.

3. The housing device according to claim 2, wherein: The cover defines a cover wire groove between the opposing pair of elongated wire grooves.

4. The housing device according to claim 1, wherein: The main housing includes an axis of elongation, and the wire slot is parallel to the axis of elongation.

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