Abstract: A method of drilling a subterranean well bore comprising, monitoring the well bore for influx of formation fluid into the well bore, and, on detection of an influx, a) stopping any pump pumping fluid into the well bore, b) operating a first blow out preventer so that it closes within a first period of time, c) operating a second blow out preventer so that it closes within a second period of time, the second blow out preventer being located below the first blow out preventer, the second period of time being longer than the first period of time, d) circulating the influx out of the well bore via a flow line extending from below the second blow out preventer.

Abstract: The present disclosure is related to apparatuses and methods measuring and processing a characteristic of subsurface earth formations penetrated by a borehole. More specifically this present disclosure relates to a method and apparatus for measuring and processing an acoustic characteristic such as formation shear wave velocity of subsurface sonic waves after these waves traverse earth formations adjoining a borehole or passing through a portion of the subsurface. The apparatus may include: a bottomhole assembly, a drill bit configured to generate an acoustic signal, at least two acoustic detectors, and a processor. The acoustic signal may include a specific multipole signal that may propagate through an earth formation along the borehole. The method may include use of the apparatus, including steps for estimating a shear velocity of the acoustic signal using signals from the at least two acoustic detectors.

Abstract: A method of communication comprising: providing a string of a plurality of connected components (2,3,5,6,7), one or more vessels running along the string to form a continuous fluid path (13); incorporating a device (3) into the string so that the device is in communication with the fluid path; inserting the string into a borehole (18) so that the device is located below a surface into which the borehole is formed and the fluid path extends from the surface to the device; providing a pressure sensor at the surface, adapted to sense the pressure of the fluid in the fluid path; filling it with a pressurized fluid; over a communication period, venting fluid, under the control of the device, from the fluid path (13) to an exterior of the string (17) at the device on occasions, so that the resulting decrease in pressure in the fluid in the fluid path can be detected by the pressure sensor; and during the communication period introducing fluid into the fluid path at a rate below 30 gallons/minute [0.113 m3/minute].

Abstract: A downhole measurement assembly, tool, and method is provided. The downhole measurement assembly includes at least one drill collar 220 having at least one compensation portion and at least one force portion with a load path 239 therethrough. The compensation portion has a different dimension from the force portion. The assembly also includes a plurality of compensation sensors 230.1, 230.2 positionable about the compensation portion to measure downhole tool pressures applied thereto, and a plurality of force sensors 230.3, 230.4 positionable about the force portion to measure downhole forces applied thereto. The compensation sensors and the force sensors are positionable about the drill collar(s) 220 in a strain configuration along the load path 239 whereby the measured downhole tool pressure is isolatable from the measured downhole forces on the drill collar(s).

Abstract: A method and a system are provided for determining the relative positions of a wellbore and an object. The wellbore is represented by a first ellipse and the object is represented by a second ellipse. The first ellipse represents the positional uncertainty of the wellbore and the second ellipse represents the positional uncertainty of the object. The method includes receiving input data relating to a measured or estimated position of the wellbore and the object. In addition, the method includes calculating an expansion factor representing an amount by which one, or both, of the first ellipse and the second ellipse can be expanded with respect to one or both of respective first and second sets of elliptical parameters so that the first and second ellipses osculate. Further, the method includes determining, based on the calculated expansion factor, position data indicative of the relative positions of the wellbore and the object.

Abstract: A drilling system and method for monitoring drilling parameters for an underground drilling operation.

Abstract: A modular tool for use in subterranean formations includes a first module, a second module and one or more connectors for connecting the first and second modules. In particular, the first module includes a first collar that at least partially defines an exterior of the tool and that includes a first engagement mechanism at a first end of the collar and a second engagement mechanism at a second end of the collar. The first module also includes a fluid passageway for passing drilling fluid therethrough. The second module has a similar configuration as includes similar architecture. The one or more connectors facilitate the connection of at least one flowline fluidly connected to an exterior of the tool, and an electrical pathway for transmitting power and/or data between the modules.

Abstract: In some embodiments, apparatus and systems, as well as methods, may operate to couple a stator to a borehole, and to move a rotor relative to the stator to generate electrical current to power a borehole tool.

Abstract: A sensor flap for a downhole tool. The downhole tool is positionable in a wellbore penetrating a subterranean formation. The sensor flap includes a sensor housing and at least one sensor. The sensor housing is operatively connectable to the downhole tool. The sensor housing is movably positionable between a retracted position in the downhole tool and an extended position in contact with a wall of the wellbore. The sensor is positionable in the sensor housing, and may include a seismic detector to measure seismic activity when the sensor housing is in contact with the wall of the wellbore.

Abstract: A fluid sensor for a downhole tool positionable in a wellbore penetrating a subterranean formation. The downhole tool has a housing with a flowline therethrough receiving a downhole fluid therein. The fluid sensor includes an insulative base positionable in the downhole tool, a conductive shield positionable on the insulative base, and a plurality of electrodes each having a non-conductive coating thereon. Each of the electrodes includes a sensing element and a pin. The sensing element is positionable in the insulative base and exposed to the downhole fluid passing through the flowline. The pin operatively connects the sensing element to a downhole unit whereby parameters of the downhole fluid are measured.

Abstract: An apparatus for determining the weight on a drill bit and axial forces along a drill string drilling though an earthen formation. The apparatus comprising an LVDT incorporated into a torsional bearing of a magneto-rheological damping system such that the LVDT senses the relative displacement and accelerations between a bearing mandrel portion and a bearing casing portion of the torsional damper. The LVDT is calibrated with respect to a spring in the damping system that resists relative motion between the bearing mandrel and bearing casing such that the output of the LVDT can be transformed into the force associated with the weight on the drill bit, and the same LVDT accelerations combined with the mass distribution along the drill string to determine axial stresses.

Abstract: Downhole tools and techniques acquire information regarding nearby conductors such as pipes, well casing, and conductive formations. At least some method embodiments provide a current flow along a drill string in a borehole. The current flow disperses into the surrounding formation and causes a secondary current flow in the nearby conductor. The magnetic field from the secondary current flow can be detected using one or more azimuthally-sensitive antennas. Direction and distance estimates may be obtainable from the azimuthally-sensitive measurements, and can be used as the basis for steering the drillstring relative to the distant conductor. Possible techniques for providing current flow in the drillstring include imposing a voltage across an insulated gap or using a toroid around the drillstring to induce the current flow.

Abstract: A monitoring assembly, including a sleeve, a sensor for monitoring one or more selected parameters, and a plurality of modules in communication with the sensor and removably disposed with the sleeve. The plurality of modules includes a first module in an active state and a second module in an inactive state. A detector is included that determines when the first module has been removed from the assembly. The second module transitions to the active state when the first module is removed from the assembly. A method of using a monitoring assembly is also included.

Abstract: The invention relates to a handling unit for drill rods having an elevator bracket (30) which can be swiveled by means of a tilt arm (34) under the influence of a tilt cylinder (32), and means (42) for detecting a position of the at least one elevator bracket (30), in which is provided at least one valve (50) as means for detecting the position of the or each elevator bracket (30) and as part of a hydraulic switching control circuit (54) which continues outside the handling unit, and at least one connecting member (52) for the at least one valve (50), which connecting member can be moved by a movement of the tilt arm (34), wherein the or each valve (50) opens or closes the hydraulic switching control circuit (54) such that the state of the switching control circuit (54) can be evaluated as position information.

Abstract: A hydraulic fluid control system for controlling pressure fluid supplied to consumers (2, 3, 4) of a rock drilling machine, a regulating valve (6, 7, 8) for each for each consumer and fluid conduits between the regulating valves and the consumers, an electronically controlled auxiliary control unit (11) having an electrically controlled auxiliary valve (14) for connection to a fluid conduit, a sensor for sensing fluid parameter values and sending sensor signals to the auxiliary control unit as sensor input signal actual values, micro-controller (12) having at least one parameter sensor input signal entry (S1-S5, I1-I5) for receiving the sensor input signal actual values and a control signal exit (V1-V6) for signal control of an auxiliary valve, the processor (12) is being arranged to compare the actual and predetermined values and to emit control signals to an auxiliary valve in response to the comparison to adjust fluid flow.

Abstract: A tubular closure assembly responsive to speed or velocity of an object. The tubular closure assembly includes at least one sensor in operable communication with an interior of a tubular. The at least one sensor sensing an object passing a first point and then a second point within the tubular. A processor receiving an output from the at least one sensor and calculating speed of the object from the first point to the second point. A control panel receiving information from the processor and a closure system movable between an open condition and a closed condition. Activatable to the closed condition by the control panel in response to the object moving from the first point to the second point at speed faster than a preset value or at a velocity outside a preset range. Also included is a method of closing a tubular of a borehole.

Abstract: An expandable reamer apparatus and methods for reaming a borehole, wherein a laterally movable blade carried by a tubular body may be selectively positioned at an inward position and an expanded position. The laterally movable blade, held inwardly by blade-biasing elements, may be forced outwardly by drilling fluid selectively allowed to communicate therewith by way of an actuation sleeve disposed within the tubular body. Alternatively, a separation element may transmit force or pressure from the drilling fluid to the movable blade. Further, a chamber in communication with the movable blade may be pressurized by way of a downhole turbine or pump. A ridged seal wiper, compensator, movable bearing pad, fixed bearing pad preceding the movable blade, or adjustable spacer element to alter expanded blade position may be included within the expandable reamer. In addition, a drilling fluid pressure response indicating an operational characteristic of the expandable reamer may be generated.

Abstract: A downhole drilling apparatus includes a drill bit, a steering tool, and an anti-oscillation sleeve deployed about a downhole end of the steering tool. The anti-oscillation sleeve is undergauge and is deployed axially between a first touch point at which the drill bit contacts the borehole wall and a second touch point at which the steering tool contacts the borehole wall.

Abstract: A technique facilitates the drilling of a wellbore by enhancing the ability to relay data. The system comprises a saver sub designed to connect a top drive unit with a wired drill pipe without requiring modification of the top drive unit. The saver sub comprises an electronics package, a battery, and an antenna coupled to a saver sub mandrel.

Abstract: A method for determining wear of a drill bit is disclosed. The method includes drilling a first hole in a worksite based on a hole pattern having a plurality of planned holes and determining an energy required to drill the first hole. The method also includes drilling a second hole in the worksite and determining an energy required to drill the second hole. The method further includes determining a wear of the drill bit using the determined energy required to drill the first hole and the determined energy required to drill the second hole.

Abstract: A rotary steerable drilling tool with an electromagnetic steering system can include a drill collar, a bit shaft, an orientation control module, a mud tube, a mud tube coupler, a universal joint, a mud sealing device, and a drill bit. The bit shaft can be mechanically coupled to the drill collar through the universal joint and the orientation control module and rotate about the universal joint. The orientation and the inclination angle of the bit shaft against the drill collar can be controlled by the orientation control module with the electromagnetic steering system. The orientation control module can include a guide track mounted on the inside wall of the drill collar, arrays of electromagnets mounted on the guide track, a positioning frame, a permanent magnet mounted on the positioning frame, a coupling tube, and at least two bearing wheels. A corresponding electromagnetic steering method is also provided.

Abstract: An apparatus and method of performing a wellbore operation. The apparatus includes a drill bit that has a cavity at an end thereof and a communication device placed in the cavity. The communication device includes a first section and a second section. An outer dimension of the second section is greater than an outer dimension of the first section. The second section includes a conduit configured to allow passage of a conductor from the drill bit to a location outside the drill bit so as to provide a direct connection of the conductor from the drill bit to an element outside the drill bit.

Abstract: A blast hole drill machine (100) including a deck frame (102), and a mast (106) mounted on the deck frame (102) is provided. A feed cylinder (120) supported on the mast (106) and configured to move in proportion to movement of a rotary drill head (114) along the mast (106). A position magnet (202) is moveably disposed on the feed cylinder (120). A linear transducer (204) extends along the mast (106) and configured to detect a movement of the position magnet (202) indicative of a change in a position of the rotary drill head (114).

Abstract: Embodiments of the present invention generally relate to extendable cutting tools for use in a wellbore. In one embodiment, a tool for use in a wellbore includes a tubular body having a bore therethrough, an opening through a wall thereof, and a connector at each longitudinal end thereof; and an arm. The arm is pivotally connected to a first piston and rotationally coupled to the body, is disposed in the opening in a retracted position, and is movable to an extended position where an outer surface of the arm extends outward past an outer surface of the body. The tool further includes the first piston. The first piston is disposed in the body bore, has a bore therethrough, and is operable to move the arm from the retracted position to the extended position in response to fluid pressure in the piston bore exceeding fluid pressure in the opening. The tool further includes a lock operable to retain the first piston in the retracted position; and a second piston operably coupled to the lock.

Abstract: In one aspect, an apparatus for use in a wellbore is provided that in one embodiment includes a drill bit having a bit body that is susceptible to corrosion when the drill bit is utilized in wellbore, an anode placed at a selected location on the bit body, a cathode associated with the bit body and a power source configured to provide electrical power to the anode to complete an electrical circuit between the anode and the bit body, wherein the supply of the electrical power to the anode arrests corrosion of the bit body when the drill bit is in the wellbore.

Abstract: In another embodiment, a method of drilling a wellbore includes running a drilling assembly into the wellbore through a casing string, the drilling assembly comprising a tubular string, an underreamer, and a drill bit; injecting drilling fluid through the tubular string and rotating the drill bit, wherein the underreamer remains locked in the retracted position; sending an instruction signal to the underreamer via modulation of a rotational speed of the drilling assembly or modulation of a drilling fluid pressure, thereby extending the underreamers; and reaming the wellbore using the extended underreamer.

Abstract: The present invention relates to a managed pressure and/or temperature drilling system (300) and method. In one embodiment, a method for drilling a wellbore into a gas hydrates formation is disclosed. The method includes drilling the wellbore into the gas hydrates formation; returning gas hydrates cuttings to a surface of the wellbore and/or a drilling rig while controlling a temperature and/or a pressure of the cuttings to prevent or control disassociation of the hydrates cuttings.

Abstract: Wireless tag fluid tracking system. A fluid can be tracked in a wellbore utilizing at least one WID tag, such as an LW tag or an RFID tag, entrained in the fluid. A WID tag reader can be disposed and/or displaced in the wellbore, for example, on a drill string or a casing string. A reader can be utilized to locate the at least one WID tag in the wellbore. A reader can be housed in a drill string sub. A fluid entrained with at least one WID tag can be utilized as a tracer fluid. A WID tag can be entrained in cement or a drilling or fracture fluid.

Abstract: A well drilling method can include sensing at least one of audio and optical signals, generating a parameter signature during a drilling operation, the parameter signature being based at least in part on the sensing, and detecting a drilling event by comparing the parameter signature to an event signature indicative of the drilling event. A well drilling system can include a control system which compares a parameter signature for a drilling operation to an event signature indicative of a drilling event, the parameter signature being based at least in part on an output of at least one audio and/or optical sensor, and a controller which controls the drilling operation in response to the drilling event being indicated by at least a partial match between the parameter signature and the event signature.

Abstract: A drill pipe identification method and apparatus utilizes a unique drill pipe identification code which is applied to each drill pipe by the manufacturer or in the field. The encoded pipe identification data is applied to the drill pipe utilizing a selected one of a variety of processes. These processes include welding, burning, optical etching utilizing lasers or welding to deposit a raised bead which is detected by tactical surface variation. The encoded identifier supported upon each drill pipe as is passes throughout the industry allows the user to investigate the history of the drill pipe which is accumulated in a central storage facility. As each user applies processes to the pipe, such as inspection or restoration, and/or employs the drill pipe in a drilling operation, the data of use is communicated to the central storage facility to enhance the drill pipe history available to subsequent potential users having come into possession of the drill pipe.

Abstract: A method for conveying logging tools (LT) and obtaining well log data from a wellbore is disclosed. The method includes running a drill string (DS) including a landing sub (LS) disposed near the lower end into a wellbore. A logging tool string (LTS) is inserted into the upper end of the DS bore. A fluid is pumped into the upper end of the DS bore to assist movement of the LTS. As the fluid is pumped behind the LTS, the cable at the surface is spooled out and the fluid pressure is monitored. The landing assembly of the LTS is landed in the LS. A diagnostic test is activated and run to determine proper functioning of the LT. A release mechanism releases the running tool portion of the LTS. The cable is spooled in. The drill pipe string is pulled upward in the wellbore as the LT are recording data.

Abstract: There is disclosed herein a method for assessing the drilling performance of a drill bit configuration used to drill at least a portion of a wellbore in a formation, comprising: determining a value of at least one drill bit performance parameter at points along the wellbore, at least including at multiple points along an interval constituting at least part of the portion drilled using the drill bit configuration; determining rock characteristics for the interval; determining the drilling performance for said drill bit configuration in the interval based on the values for the drill bit performance parameter; and assessing the effectiveness of the drill bit configuration for drilling the interval based on the determined drilling performance and the determined rock characteristics.

Abstract: A system for communicating with a drill rig includes a data acquisition board on the drill rig. A plurality of sensors are on the drill rig, and each sensor transmits data associated with the drill rig to the data acquisition board. A processor on the data acquisition board is configured to execute first logic stored in a first memory that causes the processor to format the data, store the data, and transfer the data to a mobile communications device. A method for communicating with a drill rig includes sensing an operating parameter on the drill rig and transmitting data reflective of the operating parameter to a data acquisition board on the drill rig. The method further includes formatting the data with the data acquisition board and transferring the formatted data from the data acquisition board to a mobile communications device.

Abstract: A control system and method for limiting vibrations in a drilling system, including a drill string and a drive system for providing drive torque for rotating the drill string at a reference frequency. The control system includes a sensor module for determining an uphole parameter of the drilling system, a model module provided with a model of the drilling system and adapted to provide modeled parameters of the drilling system using the drive torque as an input, a model gain module for providing a model gain vector to the model module in response to one or more of the modeled parameters and the drive torque. The model gain vector enables the model module to update the model thereby obtaining an updated model, and a control module provides a torque correction factor to the drive system depending on the modeled parameters, the uphole parameter, the reference frequency, and the drive torque.

Abstract: The Smart Reamer® Tool, Apparatus or Method is used to underream an oil or natural gas well while interlinked calipers and calibration sensors simultaneously record data relating to the geometry of the drilling operation (well diameter, diameter of the underreamed zone) and drilling fluid properties (density). Further sensors provide data on the relative position of the cutting and stabilizing blocks. Other sensors measure vibration data. All the sensors are interlinked by means of microprocessors which compare and correlate said data to automatically verify and deliver a desired wellbore diameter without the need to unnecessarily stop drilling or trip out of the hole.

Abstract: A system and method for surface steerable drilling are provided. In one example, the method includes monitoring operating parameters for drilling rig equipment and bottom hole assembly (BHA) equipment for a BHA, where the operating parameters control the drilling rig equipment and BHA equipment. The method includes receiving current inputs corresponding to performance data of the drilling rig equipment and BHA equipment during a drilling operation and determining that an amount of change between the current inputs and corresponding previously received inputs exceeds a defined threshold. The method further includes determining whether a modification to the operating parameters has occurred that would result in the amount of change exceeding the defined threshold and identifying that a problem exists in at least one of the drilling rig equipment and BHA equipment if no modification has occurred to the operating parameters. The method includes performing a defined action if a problem exists.

Abstract: The present disclosure is directed to systems and methods for rotating a drill string to overcome issues related to static friction during drilling. An embodiment includes a drive system configured to rotate the drill string through variable angular displacements and at variable rotation speeds based on control signals received by the drive system, and a control system configured transmit the control signals to the drive system, wherein the control system is configured to generate the control signals based on pipe characteristics within the drill string and friction values associated with the drill string to establish a rotation pattern of the drive system to approach a desired effective reach of surface torque generated by the drive system on the drill string.

Abstract: In one aspect, a drill bit is disclosed that in one embodiment includes a bit body that has a longitudinal axis, a blade of a selected length on a side of the bit body and substantially along the longitudinal axis, and a movable member associated with the blade that extends from a retracted position to a selected extended position along the longitudinal axis, thereby effectively extending the length of the blade when the movable member is in the selected extended position.

Abstract: A method of signal processing includes providing at least a first pressure sensor and a second pressure sensor spaced in a drilling system and using an algorithm to separate the downwardly propagating waves from the upwardly propagating waves. In one or more examples, an algorithm may include determining a velocity of pressure signals in a wellbore, time-shifting and stacking pressure signals from at least the first pressure sensor and the second pressure sensor to determine a downwardly propagating noise signal, and subtracting the downwardly propagating noise signal from at least the signal from the first pressure sensor.

Abstract: A drill for excavating a bore in the earth includes a steerable boring tool configured to excavate a bore and sensors coupled to the boring tool. The sensors are spaced apart from one another at multiple azimuthal locations around the steerable boring tool and the sensors are configured to detect a mineral property in the earth adjacent the steerable boring tool.

Abstract: A well advisor system and console for fluid gains and losses during well drilling and well construction activities. The system may be accessed through one or more workstations, or other computing devices, which may be located at a well site or remotely. The system is in communication with and receives input from various sensors. It collects real-time sensor data sampled during operations at the well site. The system processes the data, and provides nearly instantaneous numerical and visual feedback through a variety of graphical user interfaces (“GUIs”), which are presented in the form of an operation-specific console.

Abstract: A well advisor system for monitoring and managing well drilling and production operations. The system may be accessed through one or more workstations, or other computing devices, which may be located at a well site or remotely. The system is in communication with and receives input from various sensors. It collects real-time sensor data sampled during operations at the well site, which may include drilling operations, running casing or tubular goods, completion operations, or the like. The system processes the data, and provides nearly instantaneous numerical and visual feedback through a variety of graphical user interfaces (“GUIs”), which are presented in the form of operation-specific consoles.

Abstract: The present disclosure relates to a down-hole swivel sub (10) for connection in a work-string between a work-string and a down-hole apparatus, the sub comprising a first substantially cylindrical body (12) with a sleeve portion (22), a second substantially cylindrical body (28) being partially located within the sleeve portion (22) and the bodies being arranged to rotate relative to each other; and a clutch (90) disposed between said first and second substantially tubular bodies.

Abstract: A system and method for communicating with a downhole tool. A downhole tool includes a downlink receiver and a command actuator. The downlink receiver receives control information, encoded in rotation of the tool, that controls operation of the tool. The downlink receiver includes a rotation sensor and a decoder. The rotation sensor senses rotation of the tool about a longitudinal axis. The decoder demarcates fields of the control information based on rotation state transitions sensed by the rotation sensor. The rotation state transitions are transitions between a rotating state and a non-rotating state. The decoder also decodes a control value for controlling the tool based on a duration of a field of the control information. The control value is wholly encoded in the field, and the field is encoded as a non-rotating state of the tool. The command actuator applies the control value to control operation of the tool.

Abstract: Drilling instruments may include a flexible portion, such as a flexible conduit and/or a universal joint. Sensors may be utilized to detect the position of various portions of the drilling instrument, such as the flexible conduit, the universal joint, and/or a drill bit assembly.

Abstract: A method for mitigating stick-slip oscillations in borehole equipment while drilling a borehole in an earth formation is described. The borehole equipment is modelled by a computational model for computer simulation. The model has elements representing a particular mechanical and physical behavior of the borehole equipment. In a simulated stick mode of the borehole equipment, physical quantities are loaded to the elements, which quantities represent an initial state of the borehole equipment prior to a transition from stick mode to slip mode. From a simulation of such transition, a time response of rotational speeds of a drive system and bottom hole assembly of the borehole equipment is recorded and a lower limit of the rotational speed of the drive system is determined for which the rotational driven speed of the bottom hole assembly is zero.

Abstract: A position and velocity measuring tool for use on a top drive of a drilling rig having a variable frequency drive connected to an electric motor and power supply. The position and velocity measuring tool further has a processor connected to the variable frequency drive and a data storage and computer instructions for presenting an operator directional drilling steering system dashboard with numerous visual components which creates and uses a virtual encoder eliminating a failure point of a mechanical encoder.

Abstract: An installation system and method configured to install a lower completion section is provided. The installation system may comprise an installation drill pipe configured to releasably couple with a lower completion section. The installation system may comprise an electrical wet connect. The electrical wet connect may be coupled with a connector configured to establish a communication pathway between the electrical wet connect and components of the lower completion section. The lower completion section may be run in hole. Communications between a surface location and the lower completion components may be established via the electrical wet connect. The lower completion components may be tested prior to setting a lower completion section packer.

Abstract: A drilling system may include one or more downhole components to which a torque is applied. To determine the torque, the rotational velocity may be determined at two locations on a downhole component. An angle of twist may be determined by taking the integral of the rotational velocity at the two points, and the torque may be proportional to the angle of twist. The angle of twist, physical properties based on the geometry and material of the downhole component may be used, and the distance between the two locations may be used to calculate the torque.

Abstract: A housing defines a through passage along its length and is configured to support a group of electrical isolators surrounding the through passage to form an electrically isolating break in a drill string such that each isolator of the group of isolators is subject to no more than a compressive force responsive to extension and retraction of the drill string. The housing defines a housing cavity to receive an electronics package having a signal port and is configured for electrical connection of the signal port across the electrically isolating break. A housing lid can cooperate with a main housing body to define elongated slots for purposes of enhancing the emanation of a locating signal. A housing arrangement can support electrical connections from an electronics package to bridge an electrically isolating gap.