Abstract: A rod section having an electrical conductor which is arranged such that it is centered at the end and has an insulating sleeve and is fixed in the rod section such that when the rod section is joined to a further rod section having a fixed conductor, both conductors are joined together in a forcibly guided manner and the join is sealed by the sleeve in a forcibly guided manner.

Abstract: The present disclosure provides for a sensor assembly for use in a wellbore. The sensor assembly may include a rotating sub, the rotating sub coupled to a drill string and a drive shaft, the drive shaft coupled to the rotating sub. The sensor assembly may also include a nonrotating sub where the nonrotating sub is positioned generally around the drive shaft and shaft and rotatably coupled to the drive shaft and the rotating sub. The nonrotating sub may include an outer cover. The outer cover is generally tubular. The nonrotating sub may further include a sensor collar. The sensor collar is positioned within and coupled to the outer cover. The sensor collar may be coupled to the outer cover by a drive assembly. The drive assembly may include a motor adapted to rotate the sensor collar relative to the outer cover. The nonrotating sub also includes at least one positioning sensor coupled to the sensor collar.

Abstract: A mill includes a mill body defining a plurality of blades extending in a direction from a center or rotation of the mill body to a gauge surface. The blades define a cutting profile having a minimum diameter at a longitudinal endmost position. The minimum diameter is smaller than a diameter of a drop ball. The cutting profile has an intermediate diameter at most equal to the diameter of the drop ball at a longitudinal distance from the endmost position greater than the diameter of the drop ball. Shear cutters are mounted on at least one of the plurality of blades, mounted such that at least one shear cutter is mounted closer to a center of rotation of the mill body with respect to other cutters mounted to the blades. At least one insert is mounted to the at least one of the plurality of blades rotationally ahead of the shear cutters.

Abstract: A subterranean support-bolt drilling assembly has a drill bit rotatable about a central axis and including at least one cutting edge. The drilling assembly also includes a spacer coupled to a rearward end of the drill bit. A reamer member is coupled to a rearward end of the spacer, the reamer member having at least one cutting element, the at least one cutting element having a cutting edge that extends radially beyond an outer peripheral portion of the drill bit relative to the central axis. A subterranean support-bolt drill bit includes a bit body and at least one cutting element coupled to the bit body. The support-bolt drill bit has a central pilot extending from the bit body in an axially forward direction. The cutting edge of the at least one cutting element extends radially beyond the central pilot relative to a central axis of the drill bit.

Abstract: A reamer device that uses polycrystalline diamond compact (PDC) cutting elements mounted to the reamer blades. The device includes a body that defines a cutting face, a gage region and an extended end, and includes multiple blades disposed along the gage region of the body. Each of the multiple blades multiple planar surfaces, and a plurality of cutting elements positioned along the length of each of the multiple blades. The cutting elements disposed along second and third planar surfaces of each blade being slightly offset from the other blades such that in application the rotating multiple blades cause an upwardly spiraling effect.

Abstract: Methods of manufacturing a superabrasive element are disclosed. In one embodiment, a substrate and a preformed superabrasive volume may be at least partially surrounded by an enclosure and the enclosure may be sealed in an inert environment. Further, the enclosure may be exposed to an elevated pressure and preformed superabrasive volume may be affixed to the substrate. Polycrystalline diamond elements are disclosed. In one embodiment, a polycrystalline diamond element may comprise a preformed polycrystalline diamond volume bonded to a substrate by a braze material. Optionally, such a polycrystalline diamond element may exhibit a compressive stress. Rotary drill bit for drilling a subterranean formation and including at least one superabrasive element are also disclosed.

Abstract: A curved nozzle for use in a drill bit is disclosed. The curved nozzle includes a flow path that directs drilling fluid towards the face of cutters. The curved nozzle may include a base, neck, and a tip. Flow entering the nozzle, travels along a flow path through the nozzle and out the tip. The flow path may be reduced as it passes through the nozzle. The flow is curved as it flows through the neck and out the tip. The nozzle includes cooperating interior surfaces that guide the flow. The upper interior surface may include two curved zones. The first zone will be a substantially constant radius of curvature. The second zone, extending from the first zone, may be straight.

Abstract: A tracer-liner portion includes an inner tube and an outer tube, each including at least one wall having an internal surface and an external surface, the walls of the inner tube and the outer tube being impermeable to fluid flow, the outer tube having an internal diameter which is larger than the outer diameter of the inner tube, the inner tube being arranged coaxially within the outer tube such that at least a portion of the external surface of the inner tube is covered by the outer tube; the internal diameter of the outer tube exceeds the outer diameter of the inner tube by an amount sufficient to form a space between the external surface of the inner tube and the internal surface of the outer tube, and a tracer material containing a tracer compound is present in the space.

Abstract: A threaded, coupled connection having tapered, buttress-type threads, the threaded portions of the connection having a thread pitch of seven threads per inch. Preferably the pin threads of the coupled connection are pull-out threads.

Abstract: A pipe handler for assembling and deploying a string of threaded tubulars into a wellbore includes a pair of compensating bails and an elevator pivotally connected to the compensating bails. Each compensating bail includes: a first bail segment; a second bail segment; and a compensator connecting the respective first and second bail segments. Each compensator includes a load cylinder connected to the respective first bail segment and a linear actuator disposed in the respective load cylinder and operable to retract the respective second bail segment from a hoisting position to a ready position. Each second bail segment is engaged with the respective load cylinder in the hoisting position. The compensating bails are capable of supporting string weight in the hoisting position.

Abstract: A drill rig includes a base, a drill tower extending from the base, a drill pipe coupled to and supported by the drill tower, and a driving mechanism coupled to the drill tower that moves the drill pipe relative to the drill tower. The driving mechanism includes a rack and a plurality of pinions that engage the rack. The drill rig also includes an adjustment mechanism coupled to the driving mechanism, the adjustment mechanism including a plurality of rollers and an adjustment component that moves the plurality of rollers simultaneously toward the pinions to contact the rack.

Abstract: Apparatus and methods include an x-direction support structure extending in the same direction as a line extending between a well center and a V-door on a drilling rig and include a y-direction support structure moveable along the x-direction support structure. The y-direction support structure extends on a drilling rig in a direction transverse to the line extending between the well center and the V-door on the drilling rig. A racker device is carried by the y-direction support structure and is configured to connect to and carry a tubular stand used in a well drilling process, the racker device being moveable along the y-direction support structure from a position inline with the line extending between the well center and the V-door on the drilling rig to a position offline from the line to provide space for additional drilling processes along the line extending between the well center and the V-door on the drilling rig.

Abstract: A method includes conveying a whipstock and a latch anchor into a parent wellbore, the latch anchor being attached to the whipstock at a releasable connection and the parent wellbore being lined with casing that includes a latch coupling. The latch anchor is secured to the latch coupling and the whipstock is then separated from the latch anchor at the releasable connection and thereby exposing a portion of the releasable connection. The whipstock is then removed from the parent wellbore and a completion deflector is subsequently conveyed into the parent wellbore in combination with lateral tubing (with or without a multilateral junction positioned thereabove), and the completion deflector is attached to the latch coupling at the releasable connection. The lateral tubing (with or without multilateral junction positioned thereabove) is then installed to correct depth.

Abstract: Coring tools including a core tube assembly; a carrier chamber defined within the core tube assembly for storing one or more core samples drilled from a downhole formation having a wellbore fluid therein, wherein the wellbore fluid has a wellbore fluid density; a non-hydrocarbon, non-reactive heavy weight fluid (“HWF”) present within the carrier chamber, the HWF exhibiting a HWF density of about 2 pounds per gallon greater than the wellbore fluid density; a pressure housing cover selectively rotatable between (1) an open position, where the one or more core samples are able to be inserted into the carrier chamber, and (2) a closed position, where the carrier chamber is sealed; and a cover activation mechanism coupled to the core tube assembly and operable to move the pressure housing cover between the closed position and the open position.

Abstract: A system, in certain embodiments, has a composite seal with both a metal shell and an elastic core, such as an elastomer core. In one embodiment, the composite seal has an annular metal shell with a top, a bottom, and a seal interface disposed between the top and the bottom. The composite seal also has an elastomer disposed within the annular metal shell, wherein the elastomer is configured to impart pressure against the seal interface.

Abstract: A lockdown tool for locking down a high pressure wellhead with a conductor wellhead housing includes a housing that includes a conductor wellhead housing facing surface designed to come in contact with a conductor wellhead housing positioned at or near a seafloor. The housing further includes a lockdown mechanism facing surface designed to come in contact with a lockdown mechanism that is between the conductor wellhead housing and a high pressure wellhead seated in the conductor wellhead housing. The housing also includes a wellhead facing surface having a profile that matches a profile of the high pressure wellhead formed on an outer surface of the high pressure wellhead. The lockdown tool further includes a piston positioned in a cavity of the housing and a hydraulic pressure port extending through a wall of the housing for applying hydraulic pressure by an external hydraulic pressure source into the cavity of the housing.

Abstract: An emergency wellbore intervention assembly connected to a BOP having a first generally L-shaped gate valve with a first and second port on each end of the L, each side operably connected to an actuator connectable to a hydraulic control line for selectable fluid communication with a pipe, the first port connected to a choke line, and the second port connected above a lower shear ram of a BOP, the first gate valve in selectable fluid communication with the pipe to a second similar two valve assembly operably connected to a kill line and below the lower shear ram and a manually operated valve operably connected to the second gate valve for fluid engagement to a high pressure fluid source. A method for controlling a well using the two valve assemblies by selectively plugging the well and circulating fluid from the kill side to the choke side of the system.

Abstract: A borehole barrier comprises a scroll where the overlapping parts have a ratchet for radial expansion against a surrounding tubular with the ratchet controlling springing back. The outer surface can have carbide or other hard particles to penetrate the surrounding tubular for fixation. The end of the scroll forms a tapered ball seat. Expansion into place can be with a tool, or by releasing potential energy in the scroll or by using a shape memory alloy that enlarges at above its critical temperature. The scrolls can be removed by milling or allowed to dissolve or disintegrate with exposure to well fluids. The scroll design is quickly deployed and removed and is far more economical than known plugs that have the traditional seal and slip design. The balls can be milled out with their associated scrolls or flowed to the surface with produced fluids.

Abstract: A method and apparatus for sealing and filling a well which may form a part of a well abandoning operation. A tube containing well filler material is connected to a bridge plug by a connector so that the bridge plug can be positioned by moving the tube and then anchored. Once the bridge plug is anchored, the tube is disconnected and the well filler can be discharged into the well above the anchored bridge plug. In this way, the bridge plug anchoring and the filling of at least a portion of the well can be performed in a single run.

Abstract: A method for setting a barrier within a wellbore comprises deploying a first plug assembly (16) into a wellbore on a running string, wherein the first plug assembly comprises an extendable arrangement (24), and then setting the first plug assembly within the wellbore by extending the extendable arrangement. A settable medium is injected via the running string into the wellbore above the first plug assembly. To be accompanied, when published, with FIG.

Abstract: In one aspect an apparatus for use in a wellbore is disclosed that in one non-limiting embodiment includes an assembly deployable in the wellbore that includes a first fluid flow path for supplying a first fluid from a surface location to a formation zone along the wellbore and a second fluid flow path for supplying a second fluid from a surface location to the formation zone and a flow control device that combines the first fluid and the second fluid before supplying the combined fluid to the zone and may controls the proportions of such fluid to the formation zone.

Abstract: A bypass tool has a piston movable within the bore of a central housing. A control slot on an exterior wall of the piston engages a slot pin in the housing. Longitudinal movement of the piston is downward, in response to fluid pressure exerted on a ball seated on a ball seat on the piston; and spring biased upward. The control slot and slot pin rotate the piston as it moves longitudinally between a first, upper position in which bypass ports in the housing are closed, and a second, lower position in which the bypass ports are open. An intermediate longitudinal position has the ports closed, and permits pressuring up on a ball to force it through the ball seat and reset the tool in the flow through position. The ball and/or ball seat may be of resilient material to permit passage of the ball through the seat.

Abstract: A tool is incorporated into a tubing string and is run into a wellbore until an agitator at a bottom of the tool engages an obstruction in the wellbore. A helical drive arrangement between a mandrel and a sleeve causes the sleeve on the outside of the tool, to which the agitator is attached, to rotate as the mandrel is reciprocated between a downstroke and an upstroke. Rotation of the agitator disrupts the obstruction forming debris therefrom and a slurry of the debris in wellbore fluid. At the same time, reciprocation of the mandrel causes a standing valve and a travelling valve in the tool to be alternately opened and closed for pumping the slurry into the tool and from the tool into the tubing string for storage therein. Periodically the tool is tripped to surface and the stored debris is removed from the tubing string.

Abstract: A guide funnel includes segments that have a funnel surface running at an oblique angle between a bottom end and an inner circumferential edge of the top end. The width of the funnel surface is sized so that, when the guide funnel is in an assembled state, a continuous or discontinuous funnel wall is formed between adjacent segments. The bottom end can include an arcuate-shaped ring segment that forms a portion of an outer periphery of the guide funnel. The top end can be sized so that when the guide funnel is in the assembled state a side of the top end abuts a side of an adjacent top end. An adaptor ring can be secured to the inner circumferential edge of the top end and later removed and replaced with another adaptor ring to provide a different size guide funnel.

Abstract: There is taught herein a method of inducing micro fractures and fracture slip in formations thereby creating new dislocations in pre-existing fractures during hydraulic fracturing operations. An embodiment uses multi-component generated signals from multiple seismic signal generators located on or below the surface; and rotating the generated signals such that their vectors of propagation can be varied and optimized for inducing the micro-seismic and fracture slip events for highest cumulative hydrocarbon extraction considering the mechanical properties and direction of the stresses and pre-existing fractures. Embodiments relate to methods for inducing additional seismic events and fracture slip during hydraulic fracturing, particularly micro-seismic events and fracture slip which improve the short and long term production from the reservoir formation.

Abstract: A method for inhibiting freezing of low salinity water (H2O) in a subsea low salinity water injection flowline comprises providing the flowline with a pressure control system, which may include a high pressure pump and a pair of pressure shut in valves, which maintains an elevated fluid pressure within the flowline throughout low salinity water injection operations and shut in periods, during which periods the flowline remains filled with pressurized non frozen low salinity water (H2O) that may have a temperature of about ?2 degrees Celsius.

Abstract: A method of hanging a liner in a wellbore is disclosed that in one non-limiting embodiment includes: conveying a liner having a liner hanger and a liner hanger actuator into the wellbore by a service string that includes controller that determines a downhole parameter of interest relating to setting of the liner hanger; determining by the controller the parameter of interest relating to setting of the liner hanger in the wellbore; and sending a wireless liner hanger command signal from the controller in response to the determined parameter of interest to cause the liner hanger actuator to set the liner hanger in the wellbore.

Abstract: An expansion assembly for expanding a tubular in a wellbore, the expansion assembly including a top anchor comprising: a workstring; a pusher ring being coupled to the workstring by a first releasable coupling; a ramp body having one or more ramp surfaces, said ramp body being releasably coupled to the workstring by a second releasable coupling; one or more anchor segments each having one or more wedge surfaces corresponding to and engaging the ramp surfaces of the ramp body, one end of the segments engaging the pusher ring; a release ring enclosing the workstring and arranged at an opposite end of the segments; one or more key merlons connecting the release ring to the pusher ring; and activating means for releasing the first releasable coupling.

Abstract: A system and apparatus for reducing over penetration of a tubular with a shaped charge.

Abstract: The present application includes and assembly having a rigid hollowed body and an internal dart configured to traverse the length of a well bore and remove contaminants. The body having a central channel for accepting the dart. The dart includes a central passage and an exit port to selectively permit the passage of working fluid around and through the dart. The dart is configured to transition between an extended position and a seated position. The body includes one or more restricted diameter sections to create a dampener effect to minimize and distribute the impact forces upon the assembly. The assembly optionally includes one or more external wear pads, and an expandable seal coupled to the body configured to expand in diameter from the increase in pressure in the well bore. The expandable seal contacts the walls as the assembly rises in the well.

Abstract: A minimum parts bypass plunger includes a main shaft or pushrod extending through a hollow plunger body that incorporates flow passages formed in the adjacent surfaces of the pushrod or the internal bore of the plunger body. The pushrod is retained within the plunger body by respective head and tail pieces or caps that are locked to the plunger body by 360 degree crimps around the head and tail pieces. A one piece clutch is supported in the head piece. The pushrod, has an integral valve head that closes the flow passages when seated against a seat in the plunger body.

Abstract: Apparatuses and methods for extracting gas from a reservoir including a well bore having a large cross sectional area which may be determined by dividing a target flow rate of the reservoir by an actual sustained flow rate and multiplying a result by a flow path area for the actual sustained flow rate. A method of converting a well of a low pressure gas reservoir is further provided.

Abstract: Organoclay is used as an alternative emulsifier and reinforcing agent to enhance the strength of emulsified polymeric gel aqueous solutions and form water in oil emulsions. The stability of the emulsion can be controlled by controlling salinity and the intensity of initial mixing. The new system can be used for water shut-off treatments as well as a relative permeability modifier in high water permeability zones. In addition, the system can tolerate salts much better than classical surfactants. This system will be appropriate for wellbores having high temperature (>85° C.) with harsh environmental conditions.

Abstract: A method of utilizing carbon monoxide to increase oil recovery includes methods of injecting an effective amount of carbon monoxide into an oil reservoir. The carbon monoxide increases oil flow from the oil reservoir through a variety of chemical mechanisms.

Abstract: A method of initiating or accelerating the establishment of fluid communication between injection and production wells located in a formation, including injecting sufficient solvent into the wellbores of the wells such that the solvent occupies more than the horizontal sections of the wells; pressurizing the solvent column in the injection wellbore and optionally also the solvent column in the production wellbore by injecting gas such that the pressures at the toe and heel of the horizontal section of the injection well and optionally the production well are greater than a fracture pressure of the formation; maintaining the pressure in the injection wellbore and optionally also the production wellbore; depressurizing the injection wellbore and optionally the production wellbore, either simultaneously or consecutively in the case where both wellbores have been pressurized; and repeating the pressurization and depressurization steps for at least one more cycle to generate pressure swings.

Abstract: A method of completing a wellbore involves placing a series of sliding sleeves along a string of production casing in the wellbore and includes dropping a frac ball into the wellbore and landing it on a seat associated with an uppermost sleeve. Pressure is applied to activate the sleeve, open ports along the casing, and fracture a surrounding subsurface formation at a selected zone. Ball sealers are pumped down the well and seated within the sleeve ports. Additional fluid pressure is applied to cause the sleeve to shift further down the well and to release the ball, whereupon the frac ball is pumped to a next lower sleeve. This process may be repeated for multiple sleeves at multiple zones for top-down, multi-stage perforations. A novel sliding sleeve that permits a single ball to be used for activating multiple of the sleeves in series, from heel-to-toe, is also offered.

Abstract: A method for permeability improvement for a downhole coal seam by directional fracturing with pulsed detonation waves, which is applicable to gas control in coal seam areas with high gas concentration and low air permeability. The permeability improvement method is as follows: first, drilling a pulsed detonation borehole and pulsed detonation guide boreholes from a coal roadway to a coal seam respectively; then, pushing a positive electrode connected to a positive output side of an explosion-proof high-voltage electrical pulse generator to the bottom of the pulsed detonation borehole and pushing a negative electrode connected to a negative output side of the explosion-proof high-voltage electrical pulse generator to the bottom of the pulsed detonation guide borehole; connecting the pulsed detonation borehole and the pulsed detonation guide boreholes to an extraction pipeline for gas extraction, after electrical pulsed detonation fracturing for the coal seam is carried out.

Abstract: A method of homogenizing a production fluid from an oil well having one or more wellbores includes separating gas from the production fluid in a vertical or horizontal section of a well casing at a first location spaced from a heel portion of a wellbore, and injecting the separated gas into the production fluid at a second location spaced from the heel portion of the wellbore and provided downstream of the first location.

Abstract: Methods and apparatuses for determining surface wetting of a metallic material with changing well fluids. In general, the methods according to the invention include measuring electrical impedance spectroscopy (“EIS”) for a system simulating downhole conditions for the wetting of a surface. Methods and apparatuses for making EIS measurements model double-layer capacitance at a downhole surface in a well, from which the nature and quantification of the wetting of the surface can be inferred.

Abstract: A method of cementing a tubular string in a wellbore includes: deploying the tubular string into the wellbore; pumping cement slurry into the tubular string; launching a cementing plug after pumping the cement slurry; propelling the cementing plug through the tubular string, thereby pumping the cement slurry through the tubular string and into an annulus formed between the tubular string and the wellbore; and controlling flow of fluid displaced from the wellbore by the cement slurry to control pressure of the annulus.

Abstract: A method, apparatus, and program product perform lift optimization in a field with a plurality of wells, with each well including an artificial lift mechanism controlled by an associated well controller. In a central controller, a network simulation model functioning as a proxy of the field is accessed to determine an optimal allocation solution for the field, and a well-specific control signal is generated for each of the plurality of wells based upon the determined optimal allocation solution. The well-specific control signal for each of the plurality of wells is communicated to the associated well controller to cause the associated well controller to control a lift parameter associated with the artificial lift mechanism for the well.

Abstract: A downhole tool having opposing interfaces for incorporation of the downhole tool into a downhole tool string. A housing extends between the opposing interfaces, and a bore extends longitudinally through the housing between the opposing interfaces. An accelerometer is disposed within the bore of the housing for detecting acceleration of the downhole tool in response to a mechanical impact generated elsewhere within the downhole tool string. The accelerometer generates an output signal indicative of the acceleration. The downhole tool also includes a processor for processing the output signal, a memory device for storing the output signal or data generated by the processor, and an electrical energy source powering the processor and the memory device.

Abstract: A method for using a downhole probe. The method comprises providing a probe, at least one vertical cross section of the probe having an area of at least pi inches squared. The method further comprises inserting the probe into a bore of a drill collar and passing a drilling fluid through the bore of drill collar at a flow velocity of less than 41 feet per second.

Abstract: The system comprises a drilling apparatus comprising a first portion (111) and a second portion (116). In certain embodiments, the first portion may comprise a bottom hole assembly (BHA) or a drill string, and the second portion may comprise a sensor extension housing. The first portion (111) has a first diameter and the second portion (116) has a second diameter that is greater than the first diameter. The system includes a sensor pair 114) disposed within the second portion and proximate to an outer radial surface of the second portion. A processor is in communication with the sensor pair. The processor determines at least one gradient measurement based, at least in part, on outputs of the sensor pair.

Abstract: A system for optimizing placement of a second wellbore relative to a first wellbore utilizing i) steam injected into the first wellbore in combination with a temperature sensor located in the second wellbore and ii) electromagnetic (EM) fields emanating from the first wellbore in combination with an EM sensor in the second wellbore. The magnetic measurements made with the EM sensor are utilized to determine azimuthal placement of a wellbore, while temperature measurements made with the temperature sensor are utilized to determine distance for placement of the wellbore.

Abstract: A method and apparatus for directional drilling using mechanical wave detectors and a drill string having a drill bit at a drill bit end of the drill string. During an underground drilling operation in an underground formation, a mechanical wave signal is transmitted using a mechanical wave transmitter carried at the drill bit end of the drill string. The mechanical wave signal is received by an array of mechanical wave receivers at a ground surface above the underground formation. The received mechanical wave signals are processed to determine at least the location of the drill bit in the underground formation. The position and direction of travel data is communicated to a drilling control unit.

Abstract: A method for estimating a time at which a pressure window relevant observation occurred relating to an event that occurred in an open borehole penetrating an earth formation includes: receiving with a processor a pressure window relevant observation that provides input to adjusting a pressure window for drilling fluid for drilling the borehole; and estimating with the processor a time window in which a physical parameter, a chemical parameter, or a process that caused the pressure window relevant observation to occur, the time window having a start time and an end time.

Abstract: A lateral bore communication system where data signals are transmitted across the break in conductive path between a main bore and a lateral bore using a downhole structure section which has an electrode provided around a tubing portion and separated therefrom by an insulating layer.

Abstract: A three phase power system provided with a data communications system and associated method of data transmission for transmitting data over a three phase power system between a surface and a sub-surface location for an arrangement such as an oil field electrical submersible pump, the data communications system comprising a cabled connection from a surface system to a sub-surface system; a power module coupled to the cabled connection via a tuned circuit tuned to a first frequency, a data signal module coupled to the cabled connection via a tuned circuit tuned to a second frequency, independently of the coupled power module so as to minimize interference between the power signal module and data signal module during operation.

Abstract: A downhole signal transmission system provides electric radiofrequency signals that are coupled to electrically conductive or non-conductive fluids through electrical insulators. A plurality of signal repeaters are tuned to the frequencies of the radiofrequency signals, and a plurality of transmission lines terminated by resonance circuits are also provided such that the terminating resonance circuits resonate on the frequencies of the electric radiofrequency signals. The plurality of signal repeaters and plurality of transmission elements are arranged to be redundant such that a failure of one or more of the signal repeaters or a failure of one or more of the transmission elements does not substantially affect the operation of the data transmission system. The signal repeaters and transmission elements also are arranged such that a failure of any of the signal repeaters or a failure of any of the transmission elements is communicated to the surface.