Abstract: This disclosure may generally relate to systems and methods to compensate for changes in environmental conditions, such as temperature and pressure, that may be experienced by downhole tools. A downhole tool may include a tool body; a protective sleeve disposed around the tool body, wherein an annulus is formed between the protective sleeve and the tool body; a sensor coupled to the tool body; and an environmental compensation system, wherein the environmental compensation system comprises a bladder, and wherein an interior of the bladder is in fluid communication with the annulus.

Abstract: A surface system for an electromagnetic telemetry remote sensing wireless system includes a surface acquisition system configured to receive wireless signals and a plurality of nodes deployed at Earth's surface in a drilling area. Each of the nodes includes a distinct pair of first and second spaced apart electrodes and is configured to digitize voltage differences between the corresponding first and second electrodes and to wirelessly transmit the digitized voltage differences to the surface acquisition system. The voltage differences include an electromagnetic signal transmitted by a downhole tool deployed in a wellbore in the drilling area.

Abstract: An apparatus for detecting an electromagnetic signal originating in a wellbore includes an antenna comprising a pair of spaced apart electrodes in the ground spaced apart by a first distance having a midpoint at a second distance from the wellbore. The system includes at least one of a shielded electrical cable connecting each electrode to an input of a detector circuit, wherein the shielding is connected to produce common mode noise rejection; b) a second spaced apart electrode pair antenna spaced apart by one half the first distance and having a midpoint spaced ?2/2 times the second distance from the surface of the wellbore, c) a second electrode pair antenna having a common midpoint with and being orthogonal to the at least one electric dipole antenna; and d) wherein the at least one electric dipole antenna is disposed in a second wellbore, the second wellbore having substantially no electrically conductive pipe therein.

Abstract: Provided, in one example, is a wellbore tool. The wellbore tool, in this example, includes a casing having three or more pads located on an outer diameter thereof, at least one of the pads having a pocket therein. The wellbore tool of this example additionally includes one or more batteries and one or more sensors located within the pocket, and one or more additional components coupled to the one or more sensors located within an inner diameter of the casing.

Abstract: A communications system is described which comprises a transmission unit including a transmission circuit 12 operable to output a transmission signal to a ground antenna 22 driven, in use, into a ground formation, and an impedance adjusting unit 20 electrically connected between the transmission circuit 12 and the antenna 22 and operable to adjust the transmission output impedance. A ground antenna 22 is also described comprising a single rod or stake including a first active section 30, a second active section 32 spaced apart from the first section 30 and collinear or coaxial therewith, and an insulating section 34 located between the first and second sections 30, 32, holding the first and second sections 30, 32 in a spaced, collinear or coaxial relationship.

Abstract: Wellbore logging tools can include a coil antenna assembly that prevents breakage of a coil wire during downhole use under elevated pressure. The antenna assembly can include an insulator base used to help insulate the wires so elevated downhole pressures do not result in a short to a tool mandrel. The insulator base provides a recessed path for the in/out portions of the wire so manufacturing fixtures of the antenna assembly will not damage them.

Abstract: A first magnetic cavity transmitter is in the conductive tool body. A first magnetic cavity receiver is in the conductive tool body. A first transmit module is coupled to the first magnetic cavity transmitter. A first receiver module is coupled to the first magnetic cavity receiver.

Abstract: A drill string can include at least one transmit antenna and at least one receive antenna. The transmit antenna transmits at least one electromagnetic signal into a region of an earth formation. The receive antenna receives the signal from the region of the earth formation. The transmit antenna comprises one of a magnetic dipole and an electric dipole, and the receive antenna comprises the other of the magnetic dipole and the electric dipole. At least one characteristic of the region of the earth formation is determined, based at least partially on the signal received by the receive antenna. A homogeneous part of the electromagnetic signal may be reduced, to thereby increase a depth of detection of the characteristic.

Abstract: Methods and systems for testing connectivity in an EM telemetry system for transmission of a ground originating uplink EM telemetry signal. The methods and systems comprise a switch coupled to the link and configured to selectively connect the link to a test signal generator or a signal receiver, the test signal generator configured to generate a test signal and to supply it to a ground conductor, and the current within the link is measured to determine whether the link and ground conductor can properly transmit the ground originating uplink EM telemetry signal.

Abstract: An azimuthally acoustic while drilling signal receiving transducer encapsulating apparatus includes a drill collar, a receiving transducer, a preposed signal processing circuit and a master control electronics housing. The receiving transducer and the preposed signal processing circuit are encapsulated on a drill collar body individually. The receiving transducer and the signal processing circuit are electrically connected by a sealing electrical connector. The preposed signal processing circuit and the master control electronic housing are electrically connected. The signal processing circuit is preposed in terms of signal processing, and encapsulated on the drill collar, so that signal receiving and processing cable length is shortened and noise interference is reduced.

Abstract: A system for measuring geological data is disclosed. The system includes several transceivers distributed over a geographical area. Each of the transceivers has at least one transmitter and at least one receiver. The transceivers are in communication with each other. The receivers are adapted to measure at least one electrical signal. The transmitters are adapted to inject an electrical current into a subsurface area. The transmitters operate simultaneously to inject the electrical current into the subsurface area simultaneously from a number of locations.

Abstract: A receiver for a dual telemetry measurement while drilling (MWD) system and method for operating same are provided. The receiver includes a mud pulse receiver module for receiving a first signal sent using mud pulse telemetry via a pressure transducer configured to detect mud pulses transmitted through a mud column in a drill string; an electromagnetic (EM) receiver module for receiving a second signal sent using EM telemetry via the drill string and a formation; and a processer for obtaining the first signal when operating in a mud pulse mode and the second signal when operating in an EM mode and having MWD data displayed at a surface system.

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 method and system for determining information about a wellbore with coiled tubing. A downhole device may be positioned within coiled tubing and run down the wellbore to determine diagnostic information about a location with the wellbore. The downhole device may store diagnostic information in a storage device that may be analyzed when the device is returned to the surface. A downhole device may be connected to the end of a string of coiled tubing that includes a diagnostic device and memory sealed in a chamber. A flow path past the chamber is in communication with the coiled tubing string permitting the flow of fluid past the chamber. A downhole device including a diagnostic device may be connected to a recess in an exterior of a coiled tubing string.

Abstract: A technique facilitates an improved operation of a tool, such as a downhole tool. The tool is operated in a manner which provides a dynamic or cyclical loading. The dynamic or cyclical loading of the tool is sampled by a suitable sensing system at a frequency greater than the frequency of the dynamic or cyclical loading to collect detailed data on the dynamic or cyclical loading. The data is used to adjust the tool in a manner which improves operation of the tool. One technique for adjusting the tool is changing the dynamic or cyclical loading of the tool by adjusting the frequency of the dynamic or cyclical loading.

Abstract: A deep reading electromagnetic logging while drilling tool includes first and second logging while drilling subs, the first of which includes a first transmitter and a first receiver axially spaced apart from one another and the second of which includes a second transmitter and a second receiver axially spaced apart from one another. Each of the first and second transmitters and first and second receivers includes an axial antenna and collocated first and second transverse antennas. The first and second transverse antennas in the first receiver are rotationally offset by a predefined angle from the first and second transverse antennas in the first transmitter.

Abstract: A method for regulating an electromagnetic (“EM”) telemetry signal sent from downhole to surface includes determining a value of a controlled parameter of the EM telemetry signal, comparing the value of the controlled parameter to a configuration value, and adjusting the value of the controlled parameter in a first direction towards the configuration value while monitoring a feedback parameter of the EM telemetry signal when the value of the controlled parameter and the configuration value differ. The controlled parameter is one of transmission voltage and transmission current, and the feedback parameter is the other of transmission voltage and transmission current.

Abstract: Compositions, apparatuses and methods for isolating target zones for hydraulic fracturing, in particular, the use of smart fluids (i.e., magnetorheological fluids) to isolate target zones for fracturing by inducing an electromagnetic field to increase the viscosity of the fluids to form packers or plugs in the annulus of the wellbore and to isolate the target zone are disclosed.

Abstract: A logging tool for use in a borehole to obtain multicomponent resistivity induction measurements using collocated coils wherein each of the transverse antennas comprises a pair of mirror-image coils symmetrically disposed about an axis of the logging tool.

Abstract: An apparatus for determining the resistivity of formation surrounding a borehole comprising: an elongate conductive body; a pair of transmitter antennas comprising first and second antennas mounted on the body for inducing a current in the formation; and a pair of receiver antennas comprising first and second antennas mounted on the body for measuring an axial current running in the tool body at the location of the receivers; wherein the pair of transmitter antennas is located to one side of the pair of receiver antennas.

Abstract: An apparatus and method for estimating a parameter of interest of an earth formation. An apparatus includes an elongated support member; a primary transmitter on the elongated support member; and a receiver toroid on the elongated support member, the receiver toroid being positioned transversely on the elongated support member and including a single coil antenna. Methods include positioning a logging tool in a borehole in the earth formation; using a transverse receiver toroid on an elongated support member on the logging tool, wherein the transverse receiver toroid includes a single coil antenna; and producing a signal responsive to an electrical signal produced by a primary transmitter.

Abstract: An apparatus and method for estimating a parameter of interest of an earth formation, particularly relating to borehole logging methods and apparatuses for estimating electrical resistivity properties at multiple depths of investigation. The apparatus may include two or more transmitters for introducing electrical current to the earth formation. The apparatus may include a controller configured to deliver an electrical signal to the two or more transmitters either simultaneously or sequentially. The controller may deliver an electrical signal to two or more transmitters at the same frequency for estimating depth of investigation. The apparatus may include one or more receivers responsive to electric signals from the earth formation at one or more frequencies to provide data from one or more depths of investigation. The method may include steps for using the apparatus to obtain data that may be used to estimate the parameter of interest.

Abstract: A logging while drilling tool includes a directional resistivity antenna and an antenna shield having. The shield has at least one slot having at least one electrically open end formed therein. The antenna shield may include a base portion and a plurality of spaced apart fingers extending away from the base portion such that the finger ends are electrically isolated from the tool body and from one another. The antenna shield may alternatively include a plurality of spaced apart plates that are electrically isolated from the tool body and from one another. These antenna shields have been found to provide suitable physical protection for sensitive antenna components while at the same time being substantially transparent to both z-mode and x-mode electromagnetic waves.

Abstract: Embodiments of a multi-axial antenna system and system for measuring subsurface formations are generally described herein. Other embodiments may be described and claimed. In some embodiments, the multi-axial antenna system comprising at least two co-located coils wound around a torroidal-shaped bobbin. Each coil generates a magnetic field in a mutually orthogonal direction. Signals provided to the coils may be adjusted to simulate a tilted-coil antenna system.

Abstract: A combined resistivity tool incorporating both induction/propagation antennas and lateral resistivity antennas disposed in recesses of downhole tubulars, in which a lateral resistivity antenna includes an insulating base layer disposed in the recess; a toroidal antenna disposed over the insulating base layer; and a shield disposed over the recess.

Abstract: The present disclosure is directed to an antenna for transfer of information along a drill string. The antenna has an antenna coil having a long side and short side. The antenna coil is adapted to be affixed to the drill string such that the long side of the antenna coil is along the longitudinal axis of the drill string, and the short side is perpendicular to the longitudinal axis of the drill string.

Abstract: A current sensor measures an electrical current flowing in well casing or other magnetic structure. The current sensor can be installed in a tool for performing electromagnetic (EM) induction surveying in a wellbore lined with an electrically conductive casing. The tool includes an EM element to transmit or receive a magnetic field through the casing. The measured current using the current sensor can be used to relate the change of casing effect on the EM element (e.g., an induction receiver) placed inside the well casing for performing the EM induction survey.

Abstract: An apparatus for evaluating an earth formation, the apparatus including: a logging tool configured to be conveyed through a borehole penetrating the earth formation; a coil inductively coupled to the earth formation, the coil being disposed at the logging instrument; and a circuit coupled to the coil wherein the circuit and the coil form an oscillator circuit, the oscillator circuit being configured to oscillate when a circuit parameter of the oscillator circuit satisfies an oscillation criterion, the circuit parameter being related to a property of the earth formation.

Abstract: An eddy current system and method enables detection of sub-surface damage in a cylindrical object. The invention incorporates a dual frequency, orthogonally wound eddy current probe mounted on a stepper motor-controlled scanning system. The system is designed to inspect for outer surface damage from the interior of the cylindrical object.

Abstract: A method and apparatus for determining a parameter of interest of an earth formation during drilling of a borehole. A first toroidal coil antenna induces a current along a path that includes a bottomhole assembly and the formation. A second toroidal coil antenna disposed at the drillbit and oriented at a non-zero angle to the longitudinal axis of the bottomhole assembly measures an electrical signal resulting from the current, the electrical signal being a parameter of interest of the formations.

Abstract: A combined resistivity tool incorporating both induction/propagation antennas and lateral resistivity antennas disposed in recesses of downhole tubulars, in which a lateral resistivity antenna includes an insulating base layer disposed in the recess; a toroidal antenna disposed over the insulating base layer; and a shield disposed over the recess.

Abstract: A combined resistivity tool incorporating both induction/propagation antennas and lateral resistivity antennas disposed in recesses of downhole tubulars, in which a lateral resistivity antenna includes an insulating base layer disposed in the recess; a toroidal antenna disposed over the insulating base layer; and a shield disposed over the recess.

Abstract: A method and apparatus for determining a parameter of interest of an earth formation during drilling of a borehole. A first toroidal coil antenna induces a current along a path that includes a bottomhole assembly and the formation. A second toroidal coil antenna disposed at the drillbit and oriented at a non-zero angle to the longitudinal axis of the bottomhole assembly measures an electrical signal resulting from the current, the electrical signal being a parameter of interest of the formations.

Abstract: Apparatus and methods for establishing electrical communication between an instrument subsection disposed below a mud motor and an electronics sonde disposed above the mud motor in a drill string conveyed borehole logging system. Electrical communication is established via at least one conductor disposed within the mud motor and connecting the instrument sub section to a link disposed between the mud motor and the electronics sonde. The link can be embodied as a current coupling link, a magnetic coupling ling, an electromagnetic telemetry ling and a direct electrical contact link. Two way data transfer is established in all link embodiments. Power transfer is also established in all but the electromagnetic telemetry link.

Abstract: Disclosed herein are methods and apparatus using one or more toroids to measure formation anisotropy and/or vertical conductivity. In one embodiment, a disclosed method comprises: inducing a current to flow through a conductive surface of a tool body into a surrounding formation; measuring a lateral portion of the current flow; and calculating an anisotropy coefficient from the apparent conductivity so measured. The lateral current flow may be that portion of the current flowing through the tool body surface between two predetermined, axially spaced, circumferences of the tool. In an alternative embodiment, a disclosed logging tool comprises: a substantially cylindrical and conductive tool body, a toroidal transmitter, and a current measuring means. The current measuring means is configured to measure that portion of an induced current that radiates through a predetermined surface of the tool into the formation.

Abstract: A repeater is disclosed in one embodiment of the present invention as including a cylindrical housing, characterized by a proximal end and a distal end, and having a substantially cylindrical wall, the cylindrical wall defining a central bore passing therethrough. The cylindrical housing is formed to define at least one recess in the cylindrical wall, into which a repeater is inserted. The cylindrical housing also includes an annular recess formed into at least one of the proximal end and the distal end. An annular transmission element, operably connected to the repeater, is located in the annular recess. In selected embodiments, the annular transmission element inductively converts electrical energy to magnetic energy. In other embodiments, the annular transmission element includes an electrical contact to transmit electrical energy directly to another contact.

Abstract: An induction logging tool is used on a MWD bottom hole assembly. Due to the finite, nonzero, conductivity of the mandrel, conventional multi frequency focusing (MFF) does not work. A correction is made to the induction logging data to give measurements simulating a perfectly conducting mandrel. MFF can then be applied to the corrected data to give formation resistivities.

Abstract: An apparatus for monitoring conditions in subterranean borehole during drilling and pullback operations in real time. The apparatus includes a drill string having a working end. A measurement system suitable for measuring at least one operational characteristic of the apparatus and having a metallic section in direct contact with the drill string is operably connected to the working end of the drill string. At least one toroid is circumferentially disposed around a first portion of the metallic section and has toroidal electrically conductive windings. A non-conductive material is disposed around the toroid whereby contact between the toroid and a subterranean environment during operation of the apparatus is precluded.

Abstract: A logging tool is disclosed having transmitting and receiving antennas to measure formation anisotropy. The antennas may preferably be combinations of toroidal, horizontal electric dipole, and horizontal magnetic dipole antennas. In one embodiment, the tool: (a) induces a current flow in the tubing or drill string traversing the formation in a borehole; (b) measures a signal difference between two receiver antennas on the drill string; (c) determines an apparent conductivity of the formation from the resistive component of the signal difference; and (d) uses the apparent conductivity to calculate an anisotropy coefficient with a knowledge of the horizontal conductivity. The tool may further determine a second apparent conductivity of the formation from the reactive component of the signal difference, and use both apparent conductivities to calculate the anisotropy coefficient and the horizontal conductivity. The vertical conductivity can also be determined from these two calculated values in the usual manner.

Abstract: The invention provides an apparatus for making an electromagnetic measurement from within a subsurface borehole. The apparatus comprises an elongated support having electrically conductive segments and adapted for disposal within the borehole; an antenna adapted to transmit electromagnetic energy disposed on the support such that its axis is tilted or perpendicular with respect to the axis of the support; a sensor disposed on the support and adapted to detect a current flow along the support when the antenna is activated to transmit electromagnetic energy; and means to process the detected current flow to provide an indication of the measurement quality or the position of the support within the borehole.

Abstract: Methods and apparatus for detecting and monitoring the borehole effect in subsurface measurements. Toroidal sensor configurations address the undesired axial electric currents that travel along the borehole when antennas with tilted or transverse axes are used to make electromagnetic measurements. Embodiments use currents measured along the instrument to determine the quality of measured logs, the borehole size, and instrument position or orientation within the borehole.

Abstract: A logging tool is disclosed having transmitting and receiving antennas to measure formation anisotropy. The antennas may preferably be combinations of toroidal, horizontal electric dipole, and horizontal magnetic dipole antennas. In one embodiment, the tool: (a) induces a current flow in the tubing or drill string traversing the formation in a borehole; (b) measures a signal difference between two receiver antennas on the drill string; (c) determines an apparent conductivity of the formation from the resistive component of the signal difference; and (d) uses the apparent conductivity to calculate an anisotropy coefficient with a knowledge of the horizontal conductivity. The tool may further determine a second apparent conductivity of the formation from the reactive component of the signal difference, and use both apparent conductivities to calculate the anisotropy coefficient and the horizontal conductivity. The vertical conductivity can also be determined from these two calculated values in the usual manner.

Abstract: An apparatus and method for sensor signal prediction and for improving sensor signal response time, is disclosed. An adaptive filter or an artificial neural network is utilized to provide predictive sensor signal output and is further used to reduce sensor response time delay.

Abstract: A coating composite is provided for a platform surface of an antenna array for, when applied to the platform, affording isolation of radiating and receiving antennas of the array. The coating composite includes a plurality of conductively coated elongate tubes dispersed in an insulating polymer matrix at a volume loading density approaching that at which the composite begins to conduct electrically over macroscopic distances, i.e., close to the percolation threshold. The tubes are preferably comprised of microtubules comprised of biologically-derived, high-aspect rod-shaped particles of microscopic dimensions having an electroless plated metal coating thereon.

Abstract: A downhole communications system including an electromagnetic-to-acoustic signal repeater (35) for communicating information between surface equipment and downhole equipment and a method for use of the repeater (35) is disclosed. The repeater (35) comprises an electromagnetic receiver (37) and an acoustic transmitter (41). The receiver (37) receives an electromagnetic input signal and transforms the electromagnetic input signal to an electrical signal that is inputted into an electronics package (39) that amplifies the electrical signal and forwards the electrical signal to the transmitter (41) that transforms the electrical signal to an acoustic output signal that is acoustically transmitted.

Abstract: A downhole electromagnetic signal repeater (76) for communicating information between surface equipment and downhole equipment and a method for use of the repeater (76) is disclosed. The repeater (76) comprises a receiver (120) and a transmitter (124). The receiver (120) receives an electromagnetic input signal and transforms the electromagnetic input signal to an electrical signal that is inputted into an electronics package (122) that amplifies the electrical signal and forwards the electrical signal to the transmitter (124) that transforms the electrical signal to an electromagnetic output signal that is radiated into the earth.

Abstract: An azimuthally sensitive LWD tool is disclosed, comprising a transmitting antenna, a receiving antenna, wherein the receiving antenna is azimuthally focused so as to be more sensitive to changes in magnetic flux in a particular azimuthal segment of the antenna and means for measuring current induced in the receiving antenna as a result of current flowing through said transmitting antenna.

Abstract: A logging-while-drilling system is disclosed in which a first subassembly is included near the drill bit, and this subassembly comprises a conducting body with measuring means disposed in it and a first toroidal coil antenna disposed on the body, means for coupling a local communication signal generated from the measuring means to the first toroidal coil antenna, and where the measuring means includes means to energize the first toroidal coil antenna with a measurement signal and means mounted on the conductive body to receive the measurement signal after it passes through the formations to be measured.

Abstract: Measurement-while-drilling apparatus is disclosed for determining the resistivity of formations surrounding an earth borehole. An electrically conductive metal body, such as a drill collar on a drill string, is movable through the borehole. A transmitting toroidal coil antenna is disposed on the body and is energized to induce a current which travels in a path that includes the body and the formations. An electrode is disposed on the body, and an electrical signal resulting from said current is measured at the electrode to obtain an indication of the resistivity of the formations. In a disclosed embodiment, one or more electrodes can be mounted on a blade that is mechanically coupled to the body.

Abstract: Apparatus is disclosed for determining the resistivity of formations surrounding an earth borehole. An electrically conductive metal body, such as a drill collar on a drill string, is movable through the borehole. A transmitting toroidal coil antenna is disposed on the body and is energized to induce a current which travels in a path that includes the body and the formations. An electrode is disposed on the body, and an electrical signal resulting from said current is measured at the electrode to obtain an indication of the resistivity of the formations. In a disclosed embodiment, one or more electrodes can be mounted on a blade that is mechanically coupled to the body.