Abstract: An exploration system includes an artificial seismic source, sensor terminals, an environmental sensor, and a computer, wherein each of a plurality of sensor terminals is provided with a velocity or acceleration sensor which detects vibration generated by the artificial seismic source, and an identifier which is unique to the velocity or acceleration sensor; the environmental sensor detects an external environment which influences the velocity or acceleration sensor; and the computer stores a deterioration model which possibly indicates, as a degree of deterioration, performance deterioration of the velocity or acceleration sensor by providing information about the external environment as a variable, associates, with the identifier, the information about the external environment detected by the environmental sensor, stores the information about the external environment as a usage history, and determines a deterioration state of the velocity or acceleration sensor or the sensor terminal on the basis of the det

Abstract: A system, in some embodiments, comprises: a controller; and a mud pulse telemetry modulator coupled to the controller and configured to modulate a mud column using differential pulse position modulation (DPPM) code words comprising most significant bits and least significant bits, wherein the controller allocates the most significant bit in each of said code words to a first data parameter having a first importance value and the least significant bit in each of said code words to a second data parameter having a second importance value that is lower than the first importance value.

Abstract: A gap joint for use with a gap sub for electromagnetic telemetry. The gap joint has a replaceable uphole shoulder on the male gap joint component, which may be composed of a sacrificial material, to extend gap joint useful life where there is electrolysis of the component outside diameter. The gap joint also has a thicker outside diameter seal to reduce the risk of underlying O-ring extrusion and failure, again extending gap joint useful life. The thicker seal may also be able to withstand higher pressures before collapsing or experiencing punctures in unsupported areas. The replaceable shoulder and outside diameter seal can be used separately or together in a gap joint.

Abstract: Downhole assemblies comprise at least one sensor configured to sense at least one parameter relating to a downhole condition. The downhole assembly further includes a communications assembly having at least one device for controlling a characteristic of fluid flow through the downhole assembly and a processor in communication with the at least one sensor. The processor is configured to selectively alter the characteristic of fluid flow through the downhole assembly with the at least one device in response to data received from the at least one sensor.

Abstract: A system includes a set of one or more electromagnetic (EM) field sensors deployed in a borehole formed in a downhole formation, wherein the set of EM field sensors provides sensitivity to EM fields. The system also includes an EM field source that emits an EM field into the downhole formation. The system also includes a data processing system that receives measurements collected by the set of EM field sensors in response to the emitted EM field. The data processing system models the subsurface EM field based on the received measurements and identifies a plurality of flood fronts corresponding to fluid approaching the borehole from the injection wells, and adjusts injection rates to prevent injection fluid breakthrough.

Abstract: A lift frame system and method of use including a lift frame capable of being moved from a stowed position to a drill center position and a skidding pallet with at least one personnel access and egress walkway platform. The skidding pallet is capable of moving along a plurality of rails and engaging a multipurpose tower. The lift frame may include levels, a coiled tubing injector, at least one pressure control equipment, stabilizing arms, a top drive, a hook, and a set of bails.

Abstract: A brake device for engaging an inner surface of a drill string within a borehole. The brake device has a driving member that defines a plurality of wedge surfaces, a brake retainer that receives at least a portion of the driving member, and a plurality of braking elements positioned in contact with at least a portion of the outer surface of the driving member. The brake retainer has a biasing member that is operatively coupled to the driving member. The biasing member of the brake retainer biases the driving member in a proximal direction relative to the longitudinal axis of the drill string to position the wedge surfaces in contact with corresponding braking elements, and the wedge surfaces drive the braking elements radially outwardly to engage the inner surface of the drill string. The brake device is not coupled to an inner tube assembly.

Abstract: Provided is a method for controlling a resonance enhanced rotary drill comprising a drilling module and a control system for controlling one or more drilling parameters of the drilling module, which method comprises: (a) employing one or more initial characteristics of the material being drilled, and/or one or more initial drilling parameters to control the drilling module; (b) measuring one or more current drilling parameters to obtain one or more measured drilling parameters; (c) employing the one or more measured drilling parameters as an input in the control system, in order to obtain an output from the control system, which output comprises one or more calculated characteristics of the material being drilled; (d) employing the one or more calculated characteristics of the material being drilled, and/or the one or more measured drilling parameters, as an input in the control system, in order to obtain an output from the control system, which output comprises one or more calculated drilling parameters;

Abstract: The present disclosure describes methods and systems for determining source rock potential in a subterranean region of a hydrocarbon reservoir. One method includes: receiving, a terahertz (THz) scanning image from an in-situ THz scanner that is attached to a wellbore at a first subterranean location, wherein the wellbore extends into the subterranean region of the hydrocarbon reservoir; identifying, components of a source rock in the first subterranean location based on the THz scanning image; and determining, the source rock potential at the first subterranean location based on the identified components of the source rock.

Abstract: A drilling system comprising a drill string defined between an upper end and a lower end. The drill string comprises a drill pipe, a motor disposed between the drill pipe and the lower end, a drill bit disposed between the motor and the lower end, and an electronics assembly disposed within the motor or between the motor and the lower end. The electronics assembly comprises at least one sensing device.

Abstract: A casing drilling with a removable MWD tool comprising a float shoe for removably positioning the bottom of a MWD tool at and or near the drill bit inside the casing, a stabilizer attached to the top of the MWD tool for centrally positioning the MWD tool inside the casing, and a spear positioned on the stabilizer for attaching to retrieval equipment known in the art and also contemplated that after the well is drilled with casing pipe and ready for the production process, a retrieval operation may be lowered into the well to retrieve the MWD tool by attaching to the spear.

Abstract: A method that includes deploying an acoustic caliper tool in a borehole, the tool having several axially-spaced acoustic transceivers; obtaining acoustic signal reflection measurements for the transceivers; estimating a distance-to-boundary value for the transceivers based on reflection measurements; calculating a tool inclination angle based on the distance-to-boundary values; and deriving a correction value based on the angle. A system that includes an acoustic caliper tool having several axially-spaced acoustic transceivers to obtain reflection measurements; at least one processor; and at least one memory in communication with the processor, the memory storing instructions that cause the processor to: receive the acoustic signal reflection measurements; estimate a distance-to-boundary value for the transceivers based on the reflection measurements; calculate a tool inclination angle based on the distance-to-boundary values; and derive a correction value based on the angle.

Abstract: Apparatus include a downhole tool comprising an outer member; and a probe body positioned inside the outer member; an electronics carrier positioned inside the probe body; and a lateral support system, including members cooperating to maintain a relative position of the electronics carrier with respect to the probe body, and a biasing member. The plurality of members may include an outer support ring having an axial passage therethrough for receiving the electronics carrier, the outer support ring having an inner surface; and an inner support ring within the probe body having an axial passage therethrough for receiving the electronics carrier, the inner support ring having an outer surface. The biasing member may be configured to urge a member of the plurality of members against an inner surface of the probe body by urging the outer surface of the inner support ring against the inner surface of the outer support ring.

Abstract: A rock breaking seismic source and active source three-dimensional seismic combined detection system uses a tunnel boring machine for three-dimensional seismic combined detection by active seismic source and rock breaking seismic source methods. Long-distance advanced prediction and position recognition of a geological anomalous body are realized using the active source seismic method. Machine construction is adjusted and optimized according to the detection result; real-time short-distance accurate prediction of the body is realized using the cutter head rock breaking vibration having weak energy but containing a high proportion of transverse wave components as seismic sources and adopting an unconventional rock breaking seismic source seism recording and handling method. An area surrounding rock quality to be excavated is represented and assessed.

Abstract: Methods and apparatus are disclosed for generating fluid pulses in a fluid column, such as within a well. A described example fluid pulse generator has a valve member comprising a piston that is linearly movable within a piston chamber to control flow by selectively obstructing a fluid passage. The fluid passage may extend around at least a portion of the piston chamber and intersect at an angle relative to the axis of movement of the valve member. The piston is linearly movable, such as from a closed or minimal-flow position to a maximal-flow position, and optionally to any of a number or range of positions therebetween. The position of the valve member may be varied to generate fluid pulses of a selected pattern of duration, amplitude, and so forth, to generate a signal within the fluid column detectable at a location remote from the fluid pulse generator.

Abstract: A cutting element includes a table coupled to a substrate at an interface. The table includes a working surface opposite the interface and defined by a perimeter, a table thickness measured between the interface and the working surface, and a torque transmittable depression formed in the working surface of the table a distance away from the perimeter. The torque transmittable depression extends a depth into the table and has a cross-sectional profile with a torque transmittable shape. The depth of the depression may be greater than the thickness of the table, or an optional sensor may be placed in the depression.

Abstract: In a fracking context the object that will ultimately block a passage in an isolation device is introduced into the zone with the bottom hole assembly. The object is not released until the guns fire to create a pressure spike in the borehole that triggers the object retaining device to release the object. The retaining device is placed in close proximity to the isolation device and its setting tool to allow a larger object and passage in the isolation device to be used. If the guns misfire, the object is not released and comes out with the guns. The replacement guns can be pumped in because the passage in the isolation device has stayed open during the misfire. Direct and indirect object release in response to pressure created from the firing of the guns is contemplated.

Abstract: Various embodiments include systems and methods of operation with respect to well logging. The systems and methods can include a number of transmitter sensors and a number of receiving sensors arranged to operate as a system including one or more multi-pole sensors. Such systems may be controlled to generate deep high-order azimuthal sensitivity. Additional apparatus, systems, and methods are disclosed.

Abstract: A system for tracking an object in oil and gas wellbore operations wherein a releasable object carrying a first signal system is released into tube system associated with a wellbore. The first signal system communicates with one or more second signal systems positioned along the travel path of the object; along the surface of the formation; and/or throughout the wellbore. First signal system and the second signal system may communicate by RF signals. First signal system and any second signal systems positioned on the surface communicate by through-the-earth or very low frequency signals. A global positioning system may be utilized in conjunction with any second signal systems on the surface to identify the absolute location of the object in the underground wellbore. The first signal system carried by the object may be a piezoelectric system disposed to transmit a signal when the object experiences a predetermined pressure.

Abstract: The invention relates to a method for estimating pore pressure in subterranean shale formations such as gas- or organic-rich shale where pore pressure predictions based on either a resistivity log or a porosity-indicative log such as sonic tend to be inaccurate. The method involves combining the resistivity log with the porosity-indicative log using a Eaton formula to give an estimate of pore pressure which is accurate both for conventional water wet shale and for organic-rich shale.

Abstract: A system and method for testing of electrical connections, conductors, and loads prior to energizing those connections is disclosed. For example, an interlocking socket can comprise a receptacle designed to be coupled to a connector of a load. The interlocking socket can comprise a microprocessor coupled to the receptacle, the microcontroller operable for testing one or more faults in the connector, a conductor, or the load coupled to the connector. In another example, a microprocessor can be coupled to a switch comprising a conductor, where the microprocessor is operable for testing one or more faults in the conductor or a load coupled to the conductor.

Abstract: An assembly for use in subsurface drilling includes a downhole probe supported in a drill string section by centralizing features of a centralizer that is slidably removable from the drill string section. The centralizer may comprise a tubular body having a bore defined through it. A bore wall of the centralizer is fluted to provide inward contact points that support the downhole probe. The downhole probe may be supported for substantially its entire length. The centralizer may optionally comprise and/or be coated with a vibration damping and/or electrically insulating material.

Abstract: A method including selecting a forward model based on a modeled well structure and including a single modeled acoustic source located in a modeled wellbore and a plurality of modeled acoustic sensors located in a modeled source area, simulating an acoustic signal generated by the single modeled acoustic source and received by each modeled acoustic sensor, calculating phases of the simulated acoustic signals received at each modeled acoustic sensor, obtaining with a principle of reciprocity a plurality of modeled acoustic sources in the modeled source area and a single modeled acoustic sensor in the modeled wellbore, calculating phase delays of the simulated acoustic signals between each modeled acoustic source and the single modeled acoustic sensor, detecting acoustic signals generated by a flow of fluid using acoustic sensors in a wellbore, and processing the acoustic signals using the phase delays to generate a flow likelihood map.

Abstract: According to certain embodiments, formation fluid properties, such as gas-oil ratio (GOR), formation volume factor (FVF), and density, may be measured at multiple times during sampling. In one embodiment, data representing the measured properties is analyzed and a characteristic of interest is determined through extrapolation from the analyzed data. Various other methods and systems are also disclosed.

Abstract: A method for determining the bend of a tubular structure, including determining the inclination of first and second rigid objects fixed in distinct locations along the tubular structure. The method includes supplying accelerometers (A1, . . . AN) rigidly linked by the object to measure an acceleration in at least one direction of measurement (vj), the respective directions of measurement of at least two of said accelerometers being non-collinear. The measurement, by the accelerometers, of the components of the Earth's gravitational field along said directions of measurement, the measurement providing, for each of said directions, a measurement value, denoted mj for a measurement direction of index i. The method includes solving a defined matrix equation to determine the inclination ? of the object relative to the reference frame of reference.

Abstract: The disclosure relates to an electrocrushing drilling fluid with an electrocrushing drilling base fluid including a non-polar oil, water, and glycerin. The base fluid may further include a polar oil and an alkylene carbonate. The electrocrushing drilling fluid may further contain at least one additive. The electrocrushing drilling fluid may have a dielectric constant or dielectric strength of at least a set amount, an electric conductivity less than a set amount, or a combination of these properties. The disclosure further relates to an electrocrushing drilling system containing the electrocrushing drilling fluid and an electrocrushing drill bit.

Abstract: A discrete fracture network model is upscaled to a simulation grid having effective permeabilities for each grid cell. Prior to computing the effective permeabilities, the grid cells are grouped in distinct grid cell clusters, such that flow via fractures is only possible between grid cells that mutually belong to the same grid cell cluster. This is achieved by grouping fractures into distinctive fracture clusters, whereby all fractures that are physically connected with each other by intersection, either directly or indirectly via a number of other physically connected fractures, exclusively belong to one fracture cluster. Each grid cell is assigned to exclusively one fracture cluster. After defining the grid cell clusters, effective permeabilities are calculated for each grid cell using only the fractures of the fracture cluster to which the grid cell is assigned while fractures from other fracture clusters are ignored. Inter-cluster flow impediment data is assigned to selected grid cells.

Abstract: A downhole system provides a data interface to a first downhole tool such as a steerable rotary tool. The data interface uses a close proximity data connection such as a connection between inductive loops or coils or a direct wired or optical connection. The interface provides data to a second downhole tool in a drill string section adjacent to the first downhole tool. In some embodiments data is passed to a third downhole tool that includes a telemetry transmitter. The third downhole tool may comprise a MWD (measurement while drilling) tool.

Abstract: The present invention relates to a process for treating a sandstone formation comprising introducing a fluid containing glutamic acid N,N-diacetic acid or a salt thereof (GLDA) and/or methylglycine N,N-diacetic acid or a salt thereof (MGDA) and having a pH of between 1 and 14 into the formation. The invention in addition relates to a fluid suitable for use in the above process containing 5-30 wt % of glutamic acid N,N-diacetic acid or a salt thereof (GLDA) and/or methylglycine N,N-diacetic acid or a salt thereof (MGDA), a corrosion inhibitor, a surfactant, and a mutual solvent.

Abstract: Example computer-implemented method, computer-readable media, and computer system are described for generating subterranean imaging data based on initial isotropic and/or anisotropic velocity models for the vertical seismic profile (VSP) data and stored ocean bottom sensor (OBS) data. In some aspects, VSP data and OBS data of a subterranean region are received. Angle attributes for each image point are computed to image primary reflection and free surface multiples of the received VSP data and OBS data, respectively. Angle-domain common-image gathers (ADCIG) are generated according to a ray-equation method based on the angle attributes computed based on the received VSP data and OBS data, respectively. The ADCIG are further post-processed.

Abstract: A probe for a trenchless guide instrument includes an antenna, a control circuit board and at least one battery supplies power to the control circuit board; one battery is disposed inside the battery region; the control circuit board is disposed inside the electronic region; a first insulating pipe is disposed inside the antenna and outside the battery, the antenna further includes a magnetic core, and a coil winds around the magnetic cores and one end of the coil is connected to the control circuit board; the magnetic core further includes magnetic core units, each magnetic core unit is made from magnetic material, the magnetic core units are positioned on a peripheral surface of the first insulating pipe, and are insulated from each other.

Abstract: A hollow body composed of an electrically conducting material and extending longitudinally along an axis is connected at one axial end to a connection element composed of an electrically conducting material and extending along the axis. A first thread is provided on the hollow body at the one axial end running about the axis, while a second thread is provided on the connection element running about the axis, so that the second thread is mechanically supported by the first thread. An insulation-material extent between the first thread and the second thread electrically isolates the hollow body from the connection element.

Abstract: In-phase and quadrature components have different relationships with some important petrophyscial parameters, such as water saturation and mineral cation exchange capacity (CEC). In clay-containing subterranean rock formation such as shaly sand formations, these parameters can be estimated using different components of array induction tool data combined with other knowledge about the clay-containing formation. Some parameters, such as mobility and fraction of counterions are valid in cases where the pore water solution is an electrolyte of NaCl.

Abstract: An electromagnetic telemetry system can be used for determining a resistivity of a portion of a wellbore drilled through a subterranean formation. For example, the electromagnetic telemetry system can include a computing device and a downhole transceiver positioned on a well tool in the wellbore. The computing device can receive, from the downhole transceiver, a signal indicating a load impedance across an electrically insulating segment of the downhole transceiver. The computing device can determine a resistivity associated with a portion of the wellbore based on the load impedance. The computing device can determine a corrected resistivity by modifying the resistivity associated with the portion of the wellbore using a correction factor.

Abstract: A system of formation sampling while drilling, comprising: a suction pup joint provided to pump out and clean the formation fluid; a sampling pup joint provided to sample and store the formation fluid; a setting pup joint provided between the suction pup joint and the sampling pup joint and provided to establish a fluid channel between the formation fluid and the suction pup joint, the sampling pup joint; and an electrohydraulic high voltage connection device provided between the setting pup joint and the sampling pup joint. The embodiments of the present invention can be applied in the field of formation exploration technology, the function of storing the formation sample in the process of logging while drilling can be accomplished and the current logging instrument can be effectively optimized, the universality and precision of the current logging function can be effectively improved according to the embodiments of the present invention.

Abstract: The systems, devices, and methods described herein describe a control system that automatically determines a trip speed for a surge operation or a swab operation. The control system is used to automatically adjust the trip speed during the respective surge or swab operation in order to optimize the trip speed according to the changing environment of the wellbore that the bottom hole assembly traverses without exceeding the fracture gradient in the wellbore location. A well plan identifies formations along the wellbore route, dynamic real-time tracking of the tubulars added to the drill string and removed therefrom identifies the current location of the BHA in the wellbore, and pressure and fractional gradient at the location of the BHA, and in some embodiments a real-time pressure measurement from the BHA, together are used to automatically determine the maximum tripping speed possible for the formation that the BHA is traversing.

Abstract: A system for ranging between two wellbores. The target wellbore includes a conductive body (e.g., casing) disposed within a portion of the target wellbore. A second wellbore includes an electromagnetic field sensing instrument positioned within the wellbore. A current delivered to the conductive body in the target wellbore results in a magnetic field emanating from the target wellbore. The electromagnetic field sensing instrument is utilized to measure an electromagnetic gradient based on the magnetic field, which electromagnetic gradient can be utilized to determine the range between the wellbores.

Abstract: A method includes performing pulse echo measurements using a pulse echo tool. The method also includes detecting a casing collar using the pulse echo measurements performed by the pulse echo tool. The method further includes estimating a tool response of the pulse echo tool response at the casing collar using one or more processors based on the pulse echo measurement at the casing collar. The method also includes and removing the pulse echo tool response estimation from at least some of the pulse echo measurements not at the casing collar.

Abstract: A microresistivity logging tool and method for making microresistivity measurements, of which the tool includes a logging tool body having a longitudinal axis, a transmitter coil deployed in the tool body, the transmitter coil including an electrical conductor wound about a magnetically permeable core, the electrical conductor being connected to a high frequency alternating current generator deployed in the tool body, a receiver coil deployed in the tool body and including an electrical conductor wound about a magnetically permeable core, the electrical conductor being connected to a high frequency alternating voltage sensor deployed in the tool body. The transmitter and receiver coils each define a coil axis that is substantially perpendicular to the longitudinal axis of the tool body. The receiver coil and the transmitter coil are coaxial and deployed in the same plane.

Abstract: A hand-held electric circuit tester includes a probe. The probe includes a hollow body, a control circuit, a probe member, and a speaker. The probe member is operatively mounted in the hollow body, and is configured to contact a probe location of an electric circuit to be measured and electrically connect the probe location with the control circuit to produce a measurement. The control circuit is configured to generate a voice signal with reference to the measurement of the probe and output the voice signal to the speaker, which is configured to generate a voice output with reference to the voice signal indicative of the measurement. The probe can include a first switch for operating the probe member, a microphone for voice activation, or a second switch for selecting between different voices for the voice output, with the different voices stored in computer-readable memory.

Abstract: Various implementations described herein are directed to a method for assessing risks of compartmentalization. In one implementation, the method may include receiving seismic data for a formation of interest; identifying areas in the formation having a dip angle greater than about 30 degrees; performing a plurality of downhole fluid analysis (DFA) within a wellbore around the formation having the dip angle greater than about 30 degrees to identify areas experiencing mass density inversion; and determining the areas experiencing mass density inversion by DFA as having one or more risks of compartmentalization.

Abstract: Measurements made by a near-bit magnetic sensor on a bottomhole assembly are used to determine the azimuth of the BHA. The sensor may be uncalibrated. The measurement may include a cross-axial component of the magnetic field. The method may include estimating the axial component of the near-bit magnetic field using the measurement. The method may include using the estimated azimuth of the BHA for controlling a direction of drilling. The method may include estimating the component Hxy. The method may include correcting the estimated axial component using an offset between a gravitational toolface and a magnetic toolface.

Abstract: Provided in some embodiments are systems and methods for developing a hydrocarbon reservoir. A method may include, for each of a plurality of prosed hydrocarbon wells, determining a reservoir entry point corresponding to a location at a top limiting surface of the hydrocarbon reservoir, determining a reservoir exit point corresponding to a location at a bottom limiting surface of the hydrocarbon reservoir, and determining a well trajectory that includes a path that extends downward gradually from the reservoir entry point at the top limiting surface to reservoir exit point at the bottom limiting surface. The method also including generating a field development plan (FDP) for the hydrocarbon reservoir, the FDP including development information for each well of the plurality of wells, including the determined well trajectory for the well.

Abstract: A drill pipe (1), particularly for a drill string, has at least one electrical conductor (4, 7, 8, 9) and an inner pipe (2) which is arranged inside the drill pipe (1). The drill pipe (1) and the inner pipe (2) are spaced at a distance to one another in sections, wherein the drill pipe (1) and inner pipe (2) bound a hollow space (3). At least one electrical conductor (4, 7, 8, 9) is arranged on one outer side of the inner pipe.

Abstract: A system for use in a wellbore can include a first transceiver that is operable to transmit a wireless signal. The first transceiver can be positioned in an electrically isolated chamber between a tubular and a casing string for confining a transmission of the wireless signal to within the electrically isolated chamber. The system can also include a second transceiver that is positionable in the electrically isolated chamber for receiving the wireless signal from the first transceiver.

Abstract: A wellbore E-field wireless communication system, the communication system comprising a first E-field antenna, and a second E-field antenna, wherein the first antenna, and the second antenna are both arranged in a common compartment, such as an annulus of a wellbore and further arranged for transferring a signal between a first connector of the first E-field antenna and a second connector of the second E-field antenna by radio waves.

Abstract: A method for magnetic ranging includes rotating a downhole tool in a drilling well in sensory range of magnetic flux emanating from a target well having an AC magnetic source deployed therein. The downhole tool includes a magnetic field sensor deployed therein. The magnetic field sensor measures a magnetic field vector while rotating. The measured magnetic field vector is processed to compute at least one of a distance and a direction from a drilling well to a target well.

Abstract: A collar-mountable antenna for transmitting and receiving signals in a downhole environment, in at least some embodiments, comprises a bobbin having an inner surface and an outer surface, each of the inner and outer surfaces defining multiple slots, conductive wire disposed within the multiple slots on the outer surface of the bobbin, and ferrite disposed within the multiple slots on the inner surface of the bobbin.

Abstract: System and methods for performing look-ahead and look-around (LALA) inversion are provided. Measurements of formation properties accumulated by a downhole LALA tool are obtained during different stages of drilling a wellbore through layers of an underground formation. A distribution of formation properties measured for the layers behind a current layer is determined. A formation model for look-ahead inversion is defined based on the determined distribution of formation properties behind the current layer. Measurements of the current layer's formation properties collected by the downhole LALA tool are obtained. A distribution of formation properties for one or more layers ahead of the current layer is estimated based on the formation model and the measurements of formation properties obtained for the current layer. The estimated distribution includes a gradient transition of formation properties between the current layer and the one or more layers ahead of the current layer.

Abstract: Devices and methods for well logging using a wear-resistant electrode are provided. A downhole device may include a drill collar and a first electrode mounted on the drill collar. Further, the first electrode may include a wear-resistant face. The first electrode may be movably coupled within the drill collar, and the first electrode may be configured to extend and retract into a wellbore to maintain contact with a wall of the wellbore. Furthermore, the first electrode may be configured to measure impedance of a geological formation.