Abstract: In one aspect an apparatus for determining a distance between a first borehole and a second borehole during drilling of the second borehole is disclosed that in one embodiment includes a magnet on a drilling tool that rotates in the second borehole to induce a primary magnetic field in a magnetic object in the first borehole, a substantially stationary sensor on the drilling tool that detects a secondary magnetic field from the magnetic object responsive to the induced primary magnetic field, and a controller that determines the distance between the first borehole and the second borehole from the detected magnetic field.

Abstract: Methods and systems for illuminating the pore space or portions thereof of a subterranean formation may use magneto-responsive ionic liquid surfactant. For example, a method may include injecting a treatment fluid comprising a base fluid and at least one magneto-responsive ionic liquid surfactant into a wellbore penetrating a subterranean formation having a pore space; measuring a local geo-electromagnetic field within the subterranean formation at a first time and a second time; and determining a property of the pore space of the subterranean formation based on differences between the local geo-electromagnetic field at the first time and the second time.

Abstract: A method for performing a downhole operation includes marking at least one location in a wellbore using a magnetized material. The magnetized material may generate a magnetic field stronger than a magnetic field generated in the wellbore by a surrounding formation.

Abstract: The present disclosure relates to determining a property, such as resistivity, of an earth formation. A transmitter is disposed in a wellbore penetrating the formation, and a plurality of receivers are distributed on or near the earth's surface. The transmitter sends electromagnetic energy into the formation and the resulting signal, after passing through the formation, is detected by the array of receivers. The received signal is used to determine the property of the formation. This is often achieved using an inversion or numerical model of the formation being measured. The inversion takes into account changes in the background formation model due to transmitting from various locations. The measurements made on the formation can be performed while drilling the wellbore or subsequent to the drilling.

Abstract: An apparatus for making a resistivity measurement of an underground formation surrounding a borehole is provided. The apparatus includes a conductive tool body, at least one current injector electrode positioned between the tool body and a wall of the bore hole, at least one current return electrode positioned between the tool body and the wall of the bore hole, an electrical measurement device configured to monitor a voltage or a current signal indicative of an impedance imbalance, a regulator connected to the electrical measurement device, whereby the regulator is configured to receive the voltage or the current signal indicative of the impedance imbalance and is configured to generate an adjustment signal based on the voltage or the current signal indicative of the impedance imbalance.

Abstract: A downhole sensor calibration apparatus includes a rotational or gimbaling mechanism for guiding a sensing axis of an orientation responsive sensor through a three-dimensional orbit about three orthogonal axes. A method includes using measurements taken over the three-dimensional orbit to calibrate the sensor and determine other characteristics of the sensor or tool.

Abstract: In some embodiments, apparatus and systems, as well as methods, may operate to launch a set of currents into a corresponding set of existing well casings; monitor, in a well under construction, changes in at least one of a magnetic field or an electric field perturbed by the set of currents after each one of the set is launched; and determine a location of the well under construction in relation to the set of existing well casings. In some embodiments, the activities include inducing current into a drillstring located in a well under construction; monitoring, at a set of existing well casings, changes in at least one of a magnetic field or an electric field perturbed by the current after the current is induced; and determining a location of the well under construction in relation to the set of existing well casings. Additional apparatus, systems, and methods are disclosed.

Abstract: Various systems and methods for implementing and using a downhole all-optical magnetometer include downhole all-optical magnetometer sensor, including optical receiving ports that receive light pulses, a depolarizer that depolarizes received light pulses, and a polarizer that polarizes depolarized light pulses from the depolarizer. The sensor further includes a vapor-filled cell through which polarized light pulses from the polarizer are directed, wherein interactions between vapor and a magnetic field within the vapor-filled cell alter at least some of the polarized light pulses, and an optical transmitting port that directs altered light pulses from the vapor-filled cell out of the sensor.

Abstract: A steerable or non-steerable, magnetic dipole antenna for Measurement-While-Drilling (MWD) or Logging-While-Drilling (LWD) applications. The antenna elements use a hole arrangement in addition to grooves in a steel tool body, which is typically a drill collar. This antenna embodiment is extremely robust, meaning that does not significantly reduce the structural integrity of the tool body in which it is disposed. The antenna embodiment is also relatively wear resistant. The resultant magnetic dipole generated by this antenna is also electrically steerable in inclination angle from a common origin. A variable dipole moment inclination angle combined with independently measured tool rotation orientation during normal drilling allows the antenna to generate a magnetic dipole moment that may be directed at any three dimensional angle and from a common origin point at the centroid of the antenna. The antenna can also be embodied to be more sensitive to resistivity in a particular azimuthal direction.

Abstract: Methods and systems are provided for obtaining both magnetic and apparent resistivity ultra-deep reading electromagnetic measurements at the same time and/or by a single tool. The system can include a magnetometer, a current source electrode, a pair of voltage measuring electrodes, and a current return electrode. Using such a system can enable a lowering a tool into a relief well and obtaining both magnetic and apparent resistivity ultra-deep reading electromagnetic measurements in a single trip in order to provide a more accurate and faster determination of the distance and direction to a cased blown out well in order to shorten the time required to intersect and kill the blown out well.

Abstract: A magnetometer includes a sensor housing having an internal bore formed therethrough and a magnetic field sensor disposed within the internal bore of the sensor housing. The magnetic field sensor is fixedly mounted within the internal bore of the sensor housing. A magnetic flux concentrating block is disposed proximate to an end of the at least one magnetic field sensor. An electronics unit is disposed within the internal bore of the sensor housing and is operatively and communicatively connected to the magnetic field sensor. The electronics unit is configured to receive a signal from the magnetic field sensor.

Abstract: Evaluating a formation by lowering a downhole tool in a wellbore penetrating the formation, injecting a fluid into the formation at an injection zone via the downhole tool, and using a formation evaluation sensor to perform a measurement at each of a plurality of locations in the wellbore each proximate the injection zone. At least two of the plurality of measurements are compared, and a formation property is determined based on the comparison.

Abstract: Embodiments of the present invention include a system for locating and restoring service lines during pipeline restoration. According to some embodiments of the present invention, the system includes a movable chart, a plug with a marking magnet, and an attachment part. In some embodiments of the present invention, the movable cart is deployed along the inside of a pipeline. In some embodiments, the attachment part is movably coupled to the movable cart. The attachment part is configured to install a plug into the service line at a location where the service line intersects the pipeline, according to some embodiments. In other embodiments, the attachment part is configured to mark the location of the plug in the service line and remove the plug from the service line to restore a fluid connection between the service line and the pipeline.

Abstract: Certain embodiments described herein provide an estimate of the magnetic interference incident upon a drilling system using multiple magnetic sensors within a downhole portion of the drilling system in a first wellbore. Certain embodiments utilize the magnetic measurements to determine an axial interference resulting from one or more magnetic portions of the downhole portion and to provide an estimate of a relative location of a second wellbore spaced from the first wellbore.

Abstract: Aspects of this invention include a downhole tool having an angular position sensor disposed to measure the relative angular position between first and second members disposed to rotate about a common axis. A plurality of magnetic field sensors are deployed about the second member and disposed to measure magnetic flux emanating from first and second magnets deployed on the first member. A controller is programmed to determine the relative angular position based on magnetic measurements made by the magnetic field sensors. In a one exemplary embodiment, a downhole steering tool includes first and second magnets circumferentially spaced on the shaft and a plurality of magnetic field sensors deployed about the housing.

Abstract: Downhole magnetic measurement devices and methods are provided for estimation of magnetic fields during drilling. In certain embodiments, a triaxial vector magnetometer is provided and affixed to a drill string subassembly. While the drill string subassembly is rotating, as during drilling operations, an average total magnetic field value (BTwR) is determined as an average of the instantaneous vector magnitudes of the three measured orthogonal component magnetic fields. In this way, near-bit estimates of the downhole magnetic field may be obtained and used for a variety of functions. These downhole magnetic measurement devices may be useful determining magnetic fields, and estimating borehole inclination and azimuth of drill string subassemblies during drilling operations. Additionally, downhole magnetic measurement devices may be used for detecting the presence and distance to external ferromagnetic materials.

Abstract: A downhole activation system within a tubular. The system includes an axially movable mover. A first magnet attached to the mover. The first magnet axially movable with the mover. A second magnet separated from the first magnet. The second magnet magnetically repulsed by the first magnet. A biasing device urging the second magnet towards the first magnet; wherein movement of the first magnet via the mover towards the second magnet moves the second magnet in a direction against the biasing device. Also included is a method of activating an activatable member in a downhole tubular.

Abstract: A sensor assembly for sensing downhole parameters is provided. The sensor assembly is positionable in a downhole tool deployable into a subterranean formation to form a wellbore. The sensor assembly includes a carrier positionable in the downhole tool, at least one set of three accelerometers, and at least one set of three magnetometers. The carrier includes at least one set of three receptacles. The three receptacles are positioned radially about a periphery of the carrier at equal distances thereabout. The set of three accelerometers are correspondingly positionable in the at least one set of three receptacles, and the set of three magnetometers are correspondingly positionable in the at least one set of three receptacles. The set of three magnetometers includes two physical magnetometers and one virtual magnetometer. The virtual magnetometer is produced from the two physical magnetometers.

Abstract: A downhole magnetic ranging tool includes first and second axially spaced magnetic sources deployed in a downhole tool body. The first and second magnetic sources have magnetic moments that axially opposed one another. A magnetic field sensor is deployed axially between the first and second magnetic sources. The tool may be utilized, for example, in subterranean well twinning, well intercept, and well avoidance operations to obtain a separation distance and dip angle between a drilling well and a target well.

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 method of correcting accelerometer and magnetometer measurements made in a well is provided. The method includes making a series of triaxial measurements with magnetometers and accelerometers in an interval of the well to derive measured values of gravitational acceleration g, magnetic filed intensity B, and the sine of the magnetic inclination sin I. The method also includes obtaining known values of g, B and sin I for the interval and determining values of a correction to be applied to the measured values by simultaneously minimizing the difference between the measured values and the known values of g, B and sin I for the interval. The method also includes applying the correction to the measured values to obtain in situ corrected values for g, B and sin I.

Abstract: A steerable, magnetic dipole antenna for Measurement-While-Drilling (MWD) or Logging-While-Drilling (LWD) applications. The antenna elements use a hole arrangement in addition to grooves in a steel tool body, which is typically a drill collar. This antenna embodiment is extremely robust, meaning that does not significantly reduce the structural integrity of the tool body in which it is disposed. The antenna embodiment is also relatively wear resistant. The resultant magnetic dipole generated by this antenna is also electrically steerable in inclination angle from a common origin. A variable dipole moment inclination angle combined with independently measured tool rotation orientation during normal drilling allows the antenna to generate a magnetic dipole moment that may be directed at any three dimensional angle and from a common origin point at the centroid of the antenna. The antenna can also be embodied to be more sensitive to resitivity in a particular azimuthal direction.

Abstract: Methods and related systems are described for making electromagnetic measurements of a subterranean rock formation through a conductive casing of a borehole. A number of transmitters/receivers are deployed into single well having a conductive casing. A magnetic field is induced through the conductive casing and into a surrounding subterranean rock formation, and the magnetic field is detected by the receivers. The receivers have main windings, feedback winding and bucking windings. One of the receiver coils in the tool string is excited at a time, and induced voltages at all of the other receiver coils, either in straight mode, or in feedback mode, are measured.

Abstract: A method and apparatus for a rugged three-axis inclinometer for determining an object's orientation with respect to a gravitational field. Components of the apparatus include but not limited to a magnet, a non-magnetic casing, a ferrofluid, one or more non-magnetic gravitational field aligning materials attached to the magnet and a plurality of angle sensors attached to the non-magnetic casing. In this regard, when the apparatus is rotated, the gravitational field aligning materials maintain a constant orientation of the magnet and the angle sensors experience different magnetic field strengths as they rotate around the magnet. The position of the apparatus, with respect to the gravitational field can then be calculated based on the angle sensor outputs.

Abstract: Procedures are described for monitoring dynamics along a drill string during the drilling process using only surface instrumentation or using a combination of surface and downhole instrumentation. Events such as drill collar whirl may be identified from signatures found in signals generated by an electromagnetic sensor such as a magnetometer and/or from a mechanical sensor such as accelerometer. Additional embodiments are described.

Abstract: A bottom hole assembly configured for a subterranean drilling operation having a drill bit; a downhole tool deployed above the drill bit, at least a portion of the downhole tool free to rotate with respect to the drill bit about a longitudinal axis of the bottom hole assembly a sensor sub deployed axially between the drill bit and the downhole tool, the sensor sub configured to rotate with the drill bit about the longitudinal axis of the bottom hole assembly and free to rotate with respect to the downhole tool about the longitudinal axis and a tri-axial magnetic field sensor deployed in the sensor sub.

Abstract: An apparatus for determining a distance between a first borehole and a second borehole is provided that in one embodiment includes a rotating magnet on a tool configured for placement in the second borehole for inducing magnetization in a magnetic object in the first borehole, a first coil and a second coil placed radially symmetrically with respect to an axis of the tool, the first coil providing a first signal and second coil providing a second signal responsive to a magnetic flux resulting from the magnetization in the magnetic object in the first borehole, and a controller configured to combine the first signal and the second signal and determining distance between the first borehole and the second borehole using the combined signal.

Abstract: A shear wave is generated at a borehole wall. A static magnetic field is applied with a radial direction and an oscillating magnetic field is applied tangential to the borehole wall. The frequency of the oscillating field is varied until a resonance condition occurs. Motion of the formation under resonance provides an indication of a resistivity property of the earth formation.

Abstract: An instrument for measuring a property of a subsurface material, the instrument including: a magnetic material surrounding a volume in at least two dimensions; and a receiver adapted for receiving energy related to the property of the subsurface material; wherein the receiver is disposed at an exterior surface of the magnetic material.

Abstract: Methods for improving wellbore survey accuracy and placement are disclosed. The Earth's magnetic field may be measured at a magnetically clean surface location and correlated with a non-magnetic reference direction to obtain a direction of the Earth's field (e.g., a magnetic declination or a magnetic inclination). The direction of the Earth's magnetic field may in turn be processed in combination with magnetic measurements made in a subterranean borehole to obtain one or more survey parameters.

Abstract: An imaging tool made includes a pad whose curvature is chosen based on the expected range of borehole radius and the pad size so as to maintain the maximum standoff below a desired value. The curvature may be adjusted using fasteners.

Abstract: A rotating, transversely magnetized, magnet on a drill collar induces magnetization in a casing of a preexisting well. A coil rotating synchronously with the magnet produces a current at twice the frequency of rotation and having an amplitude that depends upon the distance from the magnet to the preexisting well. Alternatively, a variable magnetic field is produced in the casing using a switchable magnet.

Abstract: A wellbore tool for locating a target wellbore containing a conductive member from a second wellbore and directing the trajectory of the second wellbore relative to the target wellbore includes an electric current driver having an insulated gap; a three-axis magnetometer positioned within a non-magnetic housing that is disposed within a non-magnetic tubular, the three-axis magnetometer positioned below the electric current driver; a drill bit positioned below the three-axis magnetometer; a hollow tubular connected between the electric current driver and the three-axis magnetometer; and a measurement-while-drilling tool. The current driver generates an electric current across the gap to the portion of the tool below the insulated gap. In a method a current is generated across the insulated gap to the portion of the tool below the insulated gap to the conductive material in the target wellbore returning to a portion of the bottom hole assembly above the insulated gap thereby producing a target magnetic field.

Abstract: An apparatus for detecting a position of a component in an earth formation is disclosed. The apparatus includes: a transmitter configured to emit a first magnetic field into the earth formation and induce an electric current in the component, the transmitter having a first magnetic dipole extending in a first direction; and a receiver for detecting a second magnetic field generated by the component in response to the first magnetic field, the receiver having a second magnetic dipole extending in a second direction orthogonal to the first direction. A method and computer program product for detecting a position of a component in an earth formation is also disclosed.

Abstract: Methods for imaging geological structures include injecting magnetic materials into the geological structures, placing at least one magnetic probe in a proximity to the geological structures, generating a magnetic field in the geological structures and detecting a magnetic signal. The at least one magnetic probe may be on the surface of the geological structures or reside within the geological structures. The methods also include injecting magnetic materials into the geological structures, placing at least one magnetic detector in the geological structures and measuring a resonant frequency in the at least one magnetic detector. Methods for using magnetic materials in dipole-dipole, dipole-loop and loop-loop transmitter-receiver configurations for geological structure electromagnetic imaging techniques are also disclosed.

Abstract: An electromagnetic geological metrology system comprises: (a) a transmitter arrangement for generating outbound radiation towards a geological formation; (b) a receiver arrangement for receiving reflected electromagnetic radiation reflected from the geological formation and generating corresponding one or more received signals; and (c) a data processing arrangement for processing the one or more received signals, The system is distinguished in that: (d) the transmitter arrangement includes an antenna arrangement coupled via a switching arrangement to an energy storage arrangement; and (e) the switching arrangement is operable to discharge energy stored in the energy storage arrangement for generating the outbound radiation.

Abstract: A method and system is provided for minimizing delays in a magnetic ranging method. Delays are minimized by establishing synchronicity between triggering of a three-axis magnetometer and energisation of a solenoid assembly deployed in the borehole being drilled and the first borehole, respectively. Synchronicity enables measuring various components of the alternating magnetic field created by energisation of the solenoid assembly by the magnetometer, the moment the solenoid assembly is energised. The recorded components are used for computation of steering data for drilling the second borehole relative to the first borehole. The steering data can be determined at the surface or downhole.

Abstract: A method for magnetizing a portion of a pre-deployed casing string includes deploying an electromagnetic array in a cased wellbore and energizing the array. The array includes a plurality of axially spaced electromagnets and is configured to generate a magnetic field pattern having at least first and second pairs of magnetically opposing poles. Passive ranging measurements of the induced magnetic field may be advantageously utilized, for example, to survey and guide continued drilling of a twin well. The electromagnetic array may also be used in active ranging applications. An array of permanent magnets providing a similar magnetic field pattern may also be used in active ranging applications.

Abstract: A disclosed fracture characterization method includes: collecting three-dimensional resistivity measurements of a volume surrounding an open borehole; analyzing the measurements to determine parameters describing fractures in the volume; and providing a report to a user based at least in part on said parameters. A fluid with a contrasting resistivity is employed to make the fractures detectable by a directional electromagnetic logging tool in the borehole. illustrative parameters include fracture direction, height, extent, length, and thickness. The resistivity measurements can be augmented using a borehole wall image logging tool. Also disclosed are fracturing methods that include: positioning a directional electromagnetic logging tool proximate to a formation; fracturing the formation; monitoring fracture progression with said tool; and halting the fracturing when measurements by said tool indicate that a predetermined set of criteria have been satisfied.

Abstract: A method and apparatus for steering a drilling assembly within a reservoir of an earth formation is disclosed. The drilling assembly is positioned within the reservoir between a conductive upper layer having a DC magnetic field and a conductive lower layer having a DC magnetic field. A sensor of the drilling assembly measures a magnetic field in the reservoir resulting from the DC magnetic field of the conductive upper layer and the DC magnetic field of the conductive lower layer. A processor uses the measured magnetic field to steer the drilling assembly within the reservoir.

Abstract: A downhole sensor calibration apparatus includes a rotational or gimbaling mechanism for guiding a sensing axis of an orientation responsive sensor through a three-dimensional orbit about three orthogonal axes. A method includes using measurements taken over the three-dimensional orbit to calibrate the sensor and determine other characteristics of the sensor or tool.

Abstract: This invention relates to surveying wellbores. In particular this invention provides methods of correcting magnetic surveys for the effects introduced by magnetic mud. The method of the present invention comprises, in broad terms, measuring gravitational and magnetic fields at least one position in the wellbore; comparing the measured fields with theoretical values, and introducing scale factors to adapt the measured values to equal the theoretical values thus making it possible to cope with the effects of magnetic mud.

Abstract: An apparatus and method for estimating a parameter of interest in a downhole fluid using a fluid analyzer. The fluid analyzer may include: a electrically conductive element configured to vibrate in response to an energy source, a housing to enclose the electrically conductive element and receive a fluid, and a sensor configured to respond to shear waves induced in the fluid by the vibration of the electrically conductive element. The electrically conductive element may be relaxed during operation. Also disclosed is a method of use for the apparatus.

Abstract: A method and apparatus are provided for making directional measurements toward a formation of different resistivity that is proximate to the borehole, but which is not penetrated by the borehole. The disclosed methods and apparatus include the use of at least one insulated gap and at least one magnetometer positioned within a non-magnetic housing that is disposed within a non-magnetic tubular. An electric current is applied across the insulated gap, which results in current leaking into the surrounding formations. When a formation of contrasting resistivity is proximate to the logging apparatus, the magnetometer detects a secondary magnetic due to the contrasting formation. The direction of the secondary magnetic field can be used to determine the direction to the contrasting formation. The magnitude of the secondary magnetic field can be used to determine the distance position to the contrasting formation.

Abstract: A sensor assembly for sensing downhole parameters is provided. The sensor assembly is positionable in a downhole tool deployable into a subterranean formation to form a wellbore. The sensor assembly includes a carrier positionable in the downhole tool, at least one set of three accelerometers, and at least one set of three magnetometers. The carrier includes at least one set of three receptacles. The three receptacles are positioned radially about a periphery of the carrier at equal distances thereabout. The set of three accelerometers are correspondingly positionable in the at least one set of three receptacles, and the set of three magnetometers are correspondingly positionable in the at least one set of three receptacles. The set of three magnetometers includes two physical magnetometers and one virtual magnetometer. The virtual magnetometer is produced from the two physical magnetometers.

Abstract: An electromagnetic method and apparatus for determining the azimuthal orientation of a drill bit instrumentation sub (70), with respect to a borehole bottom drilling assembly (150) includes an electromagnet (152) fastened to the drilling assembly to produce an auxiliary alternating electromagnetic field (162) having an axis (163) that is perpendicular to the borehole axis (160). The direction of the field lines (162) generated by this magnet (152) and the simultaneous measurement of an electromagnetic field (36) generated by current flow in a blowout well casing is measured by electromagnetic field sensors in the drill bit instrument sub (70) to determine the direction to a blowout The direction of the auxiliary field (162) produced by the electromagnet (152) makes it possible to determine the direction to the blowout with reference to the direction of drilling without using an intermediate parameter such as, for example, the direction of gravity.

Abstract: Systems and methods for improved acquisition of magnetic field data for magnetic ranging while drilling are provided. In one embodiment, such a system may include a borehole assembly and data processing circuitry. The borehole assembly may include an electric current driving tool configured to cause a current to flow across a drill collar of the borehole assembly and an internal magnetometer disposed within the drill collar and between the insulated gap and an end of the borehole assembly, which may be configured to measure magnetic field signals that penetrate the drill collar.

Abstract: A method for determining electrical condition of a wired drill pipe includes inducing an electromagnetic field in at least one joint of wired drill pipe. Voltages induced by electrical current flowing in at least one electrical conductor in the at least one wired drill pipe joint are detected. The electrical current is induced by the induced electromagnetic field. The electrical condition is determined from the detected voltages.

Abstract: A method for determining the distance and/or direction of a second earth borehole with respect to a first earth borehole, includes the following steps: providing, in the first borehole, first and second spaced apart magnetic field sources; providing, in the second borehole, a magnetic field sensor subsystem for sensing directional magnetic field components; activating the first and second magnetic field sources, and producing respective first and second outputs of the magnetic field sensor subsystem, the first output being responsive to the magnetic field produced by the first magnetic field source, and the second output being responsive to the magnetic field produced by the second magnetic field source; and determining distance and/or direction of the second earth borehole with respect to the first earth borehole as a function of the first output and the second output.

Abstract: A method for magnetizing a wellbore tubular includes magnetizing the tubular at three or more discrete locations on the tubular. In exemplary embodiments the magnetized wellbore tubular includes at least one pair of opposing magnetic poles located between longitudinally opposed ends of the tubular. Wellbore tubulars magnetized in accordance with this invention may be coupled to one another to provide a magnetic profile about a section of a casing string. Passive ranging measurements of the magnetic field about the casing string may be utilized to survey and guide drilling of a twin well. Such an approach advantageously obviates the need for simultaneous access to both wells.