MILLIMETER WAVE DRILL PIPE SYSTEM

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application claims priority to U.S. Patent Provisional Application No. 63/722,817, filed on 20 Nov. 2024 entitled “MILLIMETER WAVE DRILL PIPE SYSTEM”, the entire contents of which are incorporated herein by reference in their entirety.

TECHNICAL FIELD

The subject matter described herein relates to a waveguide for use in transmitting electromagnetic waves.

BACKGROUND

A waveguide is a structure that guides waves, such as electromagnetic waves or sound, with minimal loss of energy by restricting the transmission of energy to one direction. Waveguides can be used in non-conventional drilling techniques, such as thermal drilling and/or millimeter wave drilling, to form a borehole of a well. Waveguides can be used to transmit electromagnetic waves into the borehole to enable drilling at deeper subsurface depths than conventional, rotary drilling. Specific internal features, such as corrugated grooves, can be included in a waveguide and can enhance the transmission efficiency of the electromagnetic waves provided into the borehole. Forming and deploying corrugated waveguides in single lengths of tubes can be expensive, require specialized materials and equipment, and be prone to manufacturing errors which can result in inventory waste, operational downtime of a well, and inefficient transmission of electromagnetic energy.

SUMMARY OF THE INVENTION

The disclosure relates to a millimeter wave drill pipe system.

An example implementation of the subject matter described herein is a workstring with the following features. A first section defines a waveguide therethrough. The first section is configured to operate up to a first temperature. A second section further defines the waveguide therethrough. The second section is at an uphole end of the workstring. The second section is configured to operate up to a second temperature lower than the first temperature.

Aspects of the example workstring, that can be combined with the workstring alone or in combination with other aspects, include the following. A bottomhole assembly is at a downhole end of the first section.

Aspects of the example workstring, that can be combined with the workstring alone or in combination with other aspects, include the following. A centralizer extends from an outer surface of the workstring towards an inner wall of a borehole.

Aspects of the example workstring, that can be combined with the workstring alone or in combination with other aspects, include the following. The first section is configured to operate in temperatures of up to about 870° C. The first section includes an inner, electrically conductive sleeve defining a corrugated waveguide therethrough, a metal housing surrounding the inner, electrically conductive sleeve, insulation surrounding the inner, electrically conductive sleeve, and a metallic jacket surrounding the insulation.

Aspects of the example workstring, that can be combined with the workstring alone or in combination with other aspects, include the following. The second section includes a conduit defining a portion of the waveguide therethrough.

Aspects of the example workstring, that can be combined with the workstring alone or in combination with other aspects, include the following. A third section is between the first section and the second section. The third section further defines the waveguide therethrough. The third section is configured to operate up to a third temperature greater than the first temperature and less than the second temperature.

Aspects of the example workstring, that can be combined with the workstring alone or in combination with other aspects, include the following. The third section is of sufficient length to ensure a steady-state temperature of the workstring is within a temperature limits of workstring material in each section of the workstring.

Aspects of the example workstring, that can be combined with the workstring alone or in combination with other aspects, include the following. The third section includes a metal housing defining a corrugated waveguide therethrough, insulation surrounding the metal housing, and a metallic jacket surrounding the insulation.

Aspects of the example workstring, that can be combined with the workstring alone or in combination with other aspects, include the following. A transition sub is between the second section and the third section. The transition sub defines a passage from an annulus of a borehole, defined by an outer surface of the workstring and an inner surface of a borehole, to an annulus defined by a metallic jacket and the metal housing.

Aspects of the example workstring, that can be combined with the workstring alone or in combination with other aspects, include the following. The third section includes a first portion and a second portion coupled in-line with one another by a joint with the following features. A female threaded end of the first portion or the second portion and a male threaded end of the other portion define profiles configured to mate with one another. An insulation cover is configured to surround the female threaded end and the male threaded end when the female threaded end and the male threaded end are coupled. A ring connector is coupled to either the first portion or the second portion near the joint. The ring connector extends between and rigidly coupling the metal housing and the metallic jacket. A locking sleeve surrounds the ring connector. The locking sleeve is arranged to axially move between the first portion and the second portion. A split jacket includes a first half and a second half that form a cylindrical shell when coupled. The split jacket is configured to surround the joint and the insulation cover. The split jacket is configured to be retained by the metallic jacket and the locking sleeve.

An example implementation of the subject matter described within this disclosure is a method with the following features. an electromagnetic wave is directed in a downhole direction by a workstring. The workstring includes the following features. A first section defines a first section of a waveguide therethrough. A second section further defines the waveguide therethrough. A third section is between the first section and the second section. The third section further defines the waveguide therethrough. The third section includes the following features. A metal housing defines a corrugated waveguide therethrough. Insulation surrounds the metal housing. A metallic jacket surrounds the insulation. A borehole is formed by the electromagnetic wave. The workstring is advanced through the borehole.

Aspects of the example method, which can be combined with the example method alone or with other aspects, include the following. The third section includes a first portion and a second portion. The method further includes the following steps. A joint is formed at an end of the first portion and an end of the second portion. An insulating sleeve is received by the joint to surround the joint. A locking sleeve is received by a ring connector coupled to either the first portion or the second portion near the joint. The ring connector extends between and rigidly coupling the metal housing and the metallic jacket. A split jacket is received by the joint. The split jacket surrounds the insulating sleeve. The split jacket is secured by the locking sleeve and an outer jacket of the other portion.

Aspects of the example method, which can be combined with the example method alone or with other aspects, include the following. Forming the joint includes receiving, by a female threaded end of the first portion, a male threaded end of the second portion.

Aspects of the example method, which can be combined with the example method alone or with other aspects, include the following. Forming the joint includes receiving, by a female-female coupling, a male threaded end of the first portion and a male threaded portion of the second portion.

Aspects of the example method, which can be combined with the example method alone or with other aspects, include the following. The workstring further includes a transition sub between the second section and the third section. The method further includes the following features. A cable is directed from a from an annulus of a borehole, defined by an outer surface of the workstring and an inner surface of a borehole, to an annulus defined by a metallic jacket and the metal housing.

An example of the subject matter described within this disclosure is a system with the following features. An electromagnetic wave generator is configured to emit an electromagnetic wave. A workstring is configured to direct the electromagnetic wave towards a downhole end of a borehole. The workstring includes the following features. A first section defines a waveguide therethrough. A second section further defines the waveguide therethrough. The second section is at an uphole end of the workstring. A third section is between the first section and the second section. The third section further defines the waveguide therethrough.

Aspects of the example system, which can be combined with the example system alone or in combination with other aspects, include the following. A bottomhole assembly is at a downhole end of the first section.

Aspects of the example system, which can be combined with the example system alone or in combination with other aspects, include the following. The first section is of sufficient length to ensure a steady-state temperature of the workstring is within a temperature limits of workstring material in each section of the workstring.

Aspects of the example system, which can be combined with the example system alone or in combination with other aspects, include the following. the third section includes a metal housing defining a corrugated waveguide therethrough, insulation surrounding the metal housing, and a metallic jacket surrounding the insulation.

Aspects of the example system, which can be combined with the example system alone or in combination with other aspects, include the following. The first section includes an inner, electrically conductive sleeve defining a corrugated waveguide therethrough, a metal housing surrounding the inner, electrically conductive sleeve, insulation surrounding the inner, electrically conductive sleeve, and a metallic jacket surrounding the insulation.

Aspects of the example system, which can be combined with the example system alone or in combination with other aspects, include the following. A transition sub is between the third section and the second section. The transition sub defines a passage from an annulus of a borehole, defined by an outer surface of the workstring and an inner surface of a borehole, to an annulus defined by a metallic jacket and the metal housing.

Aspects of the example system, which can be combined with the example system alone or in combination with other aspects, include the following. The first section includes a first portion and a second portion coupled in-line with one another by a joint with the following features. A female-female coupling connects a male end of the first portion and a male end of the second portion. An insulation cover is configured to surround male threads and the female-female coupling when the female-female coupling couples the male threaded ends. A ring connector is coupled to either the first portion or the second portion near the joint. The ring connector extends between and rigidly coupling the metal housing and the metallic jacket. A locking sleeve surrounds the ring connector. The locking sleeve is arranged to axially move between the first portion and the second portion. A split jacket includes a first half and a second half that form a cylindrical shell when coupled. The split jacket is configured to surround the joint and the insulation cover. The split jacket is configured to be retained by the metallic jacket and the locking sleeve.

Aspects of the example system, which can be combined with the example system alone or in combination with other aspects, include the following. The second section includes a conduit that defines a corrugated waveguide therethrough.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features will be more readily understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a diagram illustrating an exemplary embodiment of a millimeter wave drilling system including a multi-piece corrugated waveguide as described herein;

FIG. 2 is a diagram illustrating a cross sectional view of a borehole including a waveguide for low loss transmission of millimeter wave radiation as described herein;

FIG. 3 is a schematic diagram of an example workstring within a borehole;

FIG. 4 is a cross-sectional view of an insulated, high temperature portion of the workstring;

FIG. 5 is a cross-sectional view of an insulated, low temperature portion of the workstring;

FIGS. 6A-6B illustrate cross-sectional views of two implementations of uninsulated, low-temperature sections of the workstring;

FIG. 7 illustrates a perspective view of a split jacket that can be used when connected two insulated portions of the workstring;

FIGS. 8A-8B is a cross-sectional diagram of an end of an insulated portion of the workstring;

FIGS. 9A-9G are cross-sectional diagrams of two insulated portions of the workstring being coupled to one another end-to-end;

FIG. 10 illustrates a transition sub that can be used with the example workstring; and

FIGS. 11A-11B are cross sectional diagrams of example insulated pipe sections with cabling or tubing passing through an insulation layer.

DETAILED DESCRIPTION

A waveguide is a structure that guides waves, such as electromagnetic (EM) waves or sound, with minimal loss of energy by restricting the transmission of energy to one direction. Waveguides can be employed, for example, in millimeter wave drilling (MMWD) operations, to efficiently convey EM waves to depths necessary to form a well. The design and materials used to form the waveguide can affect the transmission efficiency of the EM waves transmitted in a particular transmission mode. For example, EM waves can be transmitted over long distances using a waveguide including a series of corrugated features. The corrugated features can include a pattern of repeating ridges or grooves that can extend within a length of a tube. The pattern of corrugated features (e.g., ridges, grooves, or the like) can be shaped to aid the propagation of the EM wave and can be dimensioned according to the properties (e.g., frequency) of the wave that the waveguide is designed to efficiently propagate. Corrugated waveguides can often include a dielectric or conductive coating that can improve the transmission efficiency of the waveguide.

Drilling operations, whether they include MMWD or conventional drilling, involve accommodating various geologic properties and contaminants. For example, porosity, liquid content, and hardness are factors that can determine types of drill bits and/or an intensity of EM energy used for drilling. Similarly, while drilling, unexpected “kicks” of high pressure gas or liquid can occur. Protection and monitoring systems to accommodate such situations have been developed; however, many such components for protection, monitoring, and dealing with variable drilling operations are discrete, individual components that can take-up a large footprint at a drill site and can require separate and costly maintenance.

The various implementations described herein can be employed in a variety of industries and applications wherein EM waves are transmitted, such as oil and gas production, nuclear energy, fusion reactors, drilling and mining operations, and sound or audio applications. The design and manufacturing approach of downhole waveguides can provide a less expensive alternative for any industry or application compared to purchasing multiple EM generator for multiple locations, or modifying existing structures to incorporate dedicated static waveguide systems. For operations within hazardous environments, some downhole and/or topside waveguides described herein can also provide an option to keep an EM source in a safe environment and direct EM radiation to where it is needed within the hazardous environment instead of moving the EM source within the hazardous environment, reducing the probability of a spark or arc occurring.

In some implementations, a downhole waveguide can be configured for use in MMWD during formation of a borehole. The transmission efficiency of some implementations of the dynamic waveguides described herein can also be improved by dimensioning features of internal geometry in regard to a particular transmission mode, for example, transverse electric (TE), transverse magnetic (TM), transverse electromagnetic (TEM), hybrid electric (HE), hybrid magnetic (HM), and/or hybrid electromagnetic (HEM) modes. Some implementations of the dynamic waveguides described herein can provide efficient transmission of EM waves in a variety of transmission modes.

Some implementations of the systems described herein can be formed by assembling multiple sections of a workstring that define a waveguide. Such a workstring is able to form and advance through a borehole. The workstring includes different sections with differing temperature tolerances, with sections nearer a downhole end of the workstring having a greater temperature tolerance than sections farther away from the downhole end of the workstring. The sections of the workstring can be coupled together at a topside facility, with new portions added as the workstring progresses through the borehole.

FIG. 1 is a diagram illustrating an exemplary implementation of a MMWD system 100 including an example multi-piece waveguide 108. The MMWD system 100 shown in FIG. 1 includes a gyrotron 102 connected via power cable 104 to a power supply 106 supplying power to the gyrotron 102. While primarily described as using a gyrotron, other EM sources, such as a maser or other millimeter (mm) wave emitter can be used without departing from this disclosure. The high power millimeter wave beam output by the gyrotron 102 is guided by a waveguide 108, such as a dynamic waveguide described herein. While primarily described throughout this disclosure as pertaining to millimeter wavelength energies, the subject matter described herein can be applied to other wavelengths without departing from this disclosure. The waveguide 108 can include a waveguide bend 118, a window 120, a waveguide section 126 with opening 128 for off gas emission and pressure control. A section of the waveguide is below ground 130 to help seal the borehole 148.

As part of the waveguide 108 transmission line, there is an isolator 110 to prevent reflected power from returning to the gyrotron 102 and an interface for diagnostic access 112. The diagnostic access is connected to diagnostics electronics and data acquisition 116 by low power waveguide 114. In some implementations, at the window 120, there is a pressurized gas supply unit 122 connected by plumbing 124 to the window to inject a clean gas flow across a surface of the window to help reduce prevent window deposits, such as dust or other particulates. A second pressurization unit 136 is connected by plumbing 132 to the waveguide opening 128 to help control the pressure in the borehole 148 and to introduce and remove borehole gases as needed. The window gas injection unit 122 can be operated at slightly higher pressure relative to the borehole pressure unit 136 to maintain a gas flow across the window surface. A branch line 134 in the borehole pressurization plumbing 132 can be connected to a pressure relief valve 138 to allow exhaust of volatized borehole material and window gas through a gas analysis monitoring unit 140 followed by a gas filter 142 and exhaust duct 144 into the atmosphere 146. In some implementations, the exhaust duct 144 can return the gas to the pressurization unit 136 for reuse.

Pressure in the borehole 148 can be increased in part or in whole by the partial volatilization of the subsurface material being melted. A thermal melt front 152 at a downhole end of the borehole 148 can be propagated into the subsurface strata under the combined action of the millimeter wave power and gas pressure leaving behind a ceramic (e.g., glassy) borehole wall 150. The borehole wall 150 can act as a dielectric waveguide to transmit the millimeter wave beam to the thermal front 152. Alternatively or in addition, pressure can be controlled at an uphole end of the borehole 148 to increase or reduce the velocity of the purge gas flow to maintain effective particle transport from the hole propagation region to the surface.

FIG. 2 is a diagram illustrating a cross sectional view of an example borehole including a multi-piece corrugated waveguide, which can be configured for low loss transmission of millimeter wave radiation. FIG. 2 provides a more detailed view of MMWD and corresponds to the MMWD system described in U.S. Pat. No. 8,393,410 to Woskov et. al, entitled “Millimeter-wave Drilling System.” The borehole 200 with annulus 205, glassy/ceramic wall 210 and permeated glass 215 has a waveguide assembly 220 inserted to improve the efficiency of millimeter wave beam propagation. In some implementations, the waveguide assembly can include a multi-piece corrugated waveguide that can be assembled sequentially in sections as the borehole 148 is formed. In some implementations, multiple waveguide assemblies can be inserted into the borehole. For example, multiple waveguide assemblies can be stacked upon one another to a distance of 1 km, 5 km, 10 km or more below a surface of a well.

As shown in FIG. 2, the diameter of the waveguide assembly 220 can be smaller than the borehole diameter to create an annular gap 225 for exhaust and particle extraction. The standoff distance 230 of the leading edge of the multi-piece corrugated waveguide 220 from the thermal melt front 235 of the borehole is far enough to allow the launched millimeter wave beam divergence 240 to fill the dielectric borehole 200 with the guided millimeter-wave beam 245. The standoff distance 230 is also far enough to keep the temperature at the waveguide assembly 220 low enough for survivability. The inserted waveguide assembly 220 also acts as a conduit for a pressurized gas flow 250 from the surface. This gas flow keeps the waveguide clean and contributes to the extraction and displacement of the rock material from the bore hole. The gas flow 250 from the surface mixes 255 with the volatilized out gassing of the rock material 260 to carry the condensing rock vapor to the surface through annular space 225. The exhaust gas flow 265 is sufficiently large to limit the size of the volatilized rock fine particulates and to carry them all the way to the surface. While the borehole 200 is illustrated as a vertical borehole for ease of illustration, the subject matter described herein is applicable to horizontal or deviated boreholes as well.

FIG. 3 is a schematic diagram of an example workstring 302 extending from a topside facility 304 and into the borehole 200. The topside facility 304 includes the MMWD system 100 shown in FIG. 1. The workstring 302 can be used as the multi-piece corrugated waveguide 220 previously described. The workstring 302 includes a first, upper, uninsulated, low-temperature section 306 that defines a first section of a waveguide therethrough. Nearer a downhole end 308 of the workstring 302 is an insulated, high-temperature section 310 that further defines the waveguide. The insulated, high-temperature section 310, in some implementations, is, for example, forty meters in length as the temperature within the borehole can drop sufficiently at such a distance from a bottomhole assembly 312 to not require as high of a temperature tolerance. The length of the high-temperature section can be longer or shorter based on thermal modeling of the planned drilling operations within the wellbore. In general, the insulated, high-temperature section 310 is sufficiently long to ensure a steady-state temperature of the workstring 302 is within the temperature limits of the workstring material in each section. In some implementations, the insulated, high-temperature section 310 can withstand temperatures of up to about 870° C. In some implementations, the insulated, high-temperature section can withstand temperatures of up to about 1,000° C., Between the uninsulated, low-temperature section 306 and the insulated, high-temperature section 310 is an insulated, low-temperature section 314 that further defines the waveguide. The insulated, low-temperature section 314, in some implementations, is, for example forty meters in length as the temperature within the borehole can drop below a threshold where insulation is needed for example, eighty meters away from the bottomhole assembly 312 The length of the insulated, low-temperature section can be longer or shorter based on thermal modeling of the planned drilling operations within the wellbore. In general, the insulated, low-temperature section 310 is sufficiently long to ensure a steady-state temperature of the workstring 302 is within the temperature limits of the workstring material in each section. In some implementations, the insulated, low-temperature section 310 can withstand temperatures of up to about 200° C. The uninsulated, low-temperature section 306 makes up the remining length of the workstring 302. Multiple permutation of the various types of waveguide tubulars described herein can be deployed depending on well/drilling conditions.

At a downhole end of the workstring 302 is a bottomhole assembly 312 configured and arranged to emit the EM wave into the borehole 200 from the waveguide defined by the workstring 302. Along a length of the workstring 302, several centralizers 316 that extend from an outer surface of the workstring 302 towards an inner wall of the borehole 200 can be used. Such centralizers 316 help insure stability of the workstring 302 during drilling operations. While illustrated as using two centralizers, greater or fewer centralizers 316 can be used without departing from this disclosure. In some implementations, cables 318, hydraulic lines, or pneumatic lines can run along a length of the workstring 302 between the topside facility 304 and the bottomhole assembly 312.

FIG. 4 is a planar cross-sectional view of an insulated, high-temperature section 310 of the workstring 302. An innermost layer of the insulated, high-temperature section 310 includes an inner, electrically conductive sleeve 402 defining the corrugated waveguide 404 therethrough. Surrounding and contacting the inner, electrically coupled sleeve 402 is a metal housing 406 with a high temperature resistance, for example, up to about 870° C. In some implementations, the metal housing 406 has a temperature resistance up to about 1000°. Surrounding and contacting the metal housing 406 is a layer of insulation 408. An outer surface of the insulated, high-temperature section 310 includes a metallic jacket 410 that surrounds and retains the insulation 408. The metallic jacket 410 is rotably coupled to the metal housing 406 such that they rotate substantially in unison (accounting for torque ripple and distortion). Details of such coupling are described later within this disclosure. While primarily illustrated as including layers, arranged from inward to outward, that include the electrically conductive sleeve 402, the metal housing 406, the layer of insulation 408, and the metallic jacket 410, other arrangement can be used without departing from this disclosure. For example, in some implementations, the layer of insulation 408 is positioned between the conductive sleeve 402 and the metal housing 406.

FIG. 5 is a cross-sectional view of the of the workstring 302. The insulated, low temperature section 314 is substantially similar to the insulated, high-temperature section 310 previously described with the exception of any differences described herein. Rather than having an inner, electrically coupled sleeve 402, the metal housing 406 of the insulated, low-temperature section defines the corrugated waveguide therethrough. The metal housing 406 of the insulated, low-temperature section 314 is made of a material better equipped for acting as a waveguide, for example, the metal housing 406 is made from an electrically conductive material, such as aluminum. The metal housing 406 of the insulated, low-temperature section 314 does not need a high temperature resistance. This section of the workstring is sufficiently long to separate the uninsulated, low-temperature section 306 from the bottom hole assembly such that no heat-induced damage occurs to the uninsulated, low-temperature section 306.

FIGS. 6A-6B illustrate cross-sectional views of two implementations of uninsulated, low-temperature section 306 of the workstring 302. This section of the workstring is sufficiently far enough away from the bottom hole assembly that insulation is not necessary. In some implementations, as shown in FIG. 6A, the uninsulated, low-temperature section 306A includes a single conduit 602A that defines the corrugated waveguide 404 therethrough. In such implementations, the single conduit 602A is made from an electrically conductive material, such as aluminum. In some implementations, as shown in FIG. 6B, the uninsulated, low-temperature section includes a conduit or metal body 602B housing the conductive, corrugated sleeve 402 that defines the corrugated waveguide 404 therethrough. In such implementations, the conduit or metal body 602B can be made of, for example, high strength steel as the electrical conductivity is provided by the corrugated sleeve 402.

Focusing on the insulated sections (310, 314), such sections are divided into smaller portions that are arranged to couple to one another to form each section and interconnect different sections. In the cases of insulated sections, coupling joints between each smaller portion can include insulation retained at least in part by two split jackets 700, an example of which is illustrated in FIG. 7. Two split jackets 700 combine to form a conduit or cylindrical shell to retain insulation to the joint. Details on such a configuration are described below. Throughout this disclosure, the joints, once fully connected, fluidically isolate the corrugated waveguide 404 from an annulus of the borehole in which the workstring is included. That is, the pressure drop through the joint is sufficient to prevent any leakage sufficient enough to allow the volatilized rock fine particulates to be carried all the way to the topside facility 304 (FIG. 3).

Focusing first on an end 800 of an insulated portion of either the insulated, low-temperature section 314 or the insulated, high-temperature section 310, as shown in FIGS. 8A-8B, the end includes the metal housing 406 surrounded by insulation 408 and the metal jacket 410. The metal jacket 410 is coupled to the metal housing 406 by a ring connector 802. The ring connector is attached to the metal body by pins 804 and to the outer jacket by a weld 806. While primarily illustrated and described as being connected by pins and welds at specific locations, the ring connector 802 can be attached to the metal jacket 410 and/or metal housing 406 in different ways without departing from this disclosure. For example, fasteners, welds, adhesives, crimps, or interference fits can be used without departing from this disclosure. The connection formed by the ring connector 802 between the metal jacket 410 and the metal housing 406 allows torque, tension, and/or compression to be exchanged between the metal jacket 410 and the metal housing 406. A sleeve 808 is positioned to slide onto the end 800. The sleeve 808 has substantially a same outer diameter (within manufacturing tolerances) as the metal jacket 410 and is made from a material with similar mechanical, chemical, and thermal properties as the metal jacket 410.

FIGS. 9A-9E are cross sectional diagrams of two insulated portions (902A, 902B) of the workstring 302 being coupled to one another end-to-end. As shown in FIG. 9A, the sleeve 808 is placed around a one of the two portions (902A, 902B). The two ends are then threaded together. The metal housings 406 define male and female threads (not shown) configured to mate with one another. Next, as shown in FIG. 9B, insulation 408 is wrapped around the joint 904 formed by the mated male and female threads coupling the two portions (902A, 902B) together. While the description primarily describes the joint 904 as being defined by male threads 904 and female threads 906 as shown in FIG. 9F, alternatively or in addition, a female-female coupling 908, shown in FIG. 9G, can be used to connect two portions that each have male threads 904 on a connection end.

Next, as shown in FIG. 9C, the split jackets 700 are added to surround the insulation. The split jackets 700 define a profile that includes a shoulder 906 sized to slide under the metal jacket 410 on the portion 902A, as shown in FIG. 9D, such that the split jackets 700 are retained by the metal jacket 410 of the portion 902A. The sleeve 808 is then axially moved to lock the split jacket in place by surrounding a second shoulder 906 at a second end of the split jackets 700. In some implementations, tabs 810 are machined into the sleeve 808. Such tabs 810 act as a collet to bend over the ring connector 802, snapping into a slot and shoulder machined into the ring connector 802. Alternatively or in addition, snap ring can be used for the sleeve 808 engage slots in an upper portion of the metal jacket 410 to secure the sleeve 808 axially. Other actuable fastening systems can be used without departing from this disclosure.

FIG. 10 illustrates a transition sub 1002 that can be used with the example workstring 302 for example, at a transition between the uninsulated, low-temperature section 306 and the insulated, low-temperature section 314. The transition sub 1002 defines a passage from an annulus defined by an inner wall of the borehole 200 and an outer wall of the workstring 302, to an annulus defined by the metallic jacket 410 and the metal housing 406. The transition sub 1002 can be used to the direct cables 318, hydraulic lines, or pneumatic lines from the borehole into the annulus defined by the metallic jacket 410 and the metal housing 406. This annulus protects the cables 318, hydraulic lines, or pneumatic lines from the higher temperatures within the borehole within eighty meters of the bottomhole assembly 312.

The cables, hydraulic lines, or pneumatic lines can run directly through the insulation 408 as shown in FIG. 11A, or they can be directed through a conduit 1102 within the insulation 408 as shown in FIG. 11B.

In operation, an EM wave is directed through the workstring 302. This EM wave forms a borehole, allowing the workstring 302 to further advance through the geologic formation through which the borehole 200 is formed. As the workstring 302 advances, additional portions or sections are added to the workstring 302 as previously described.

Certain exemplary embodiments have been described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the systems, devices, and methods disclosed herein. One or more examples of these embodiments have been illustrated in the accompanying drawings. Those skilled in the art will understand that the systems, devices, and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments and that the scope of the present invention is defined solely by the claims. The features illustrated or described in connection with one exemplary embodiment may be combined with the features of other embodiments. Such modifications and variations are intended to be included within the scope of the present invention. Further, in the present disclosure, like-named components of the embodiments generally have similar features, and thus within a particular embodiment each feature of each like-named component is not necessarily fully elaborated upon.

Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about,” “approximately,” and “substantially,” are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and/or interchanged, such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise.

One skilled in the art will appreciate further features and advantages of the invention based on the above-described embodiments. Accordingly, the present application is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. All publications and references cited herein are expressly incorporated by reference in their entirety.