Abstract: Measurement of the inclination and azimuthal direction of a borehole extending beneath an obstacle, such as a body of water, which utilizes magnetic and gravity sensors at the drill bit of a borehole being drilled. Embodiments of the present invention determine and remove remanent field components and the effects of ferromagnetic permeability prior to and during drilling of the borehole.

Abstract: The present invention is directed to an apparatus for use on a structural member having a longitudinal axis, the structural member being configured to propagate stress wave energy in an operational state, the stress wave energy being characterized by an operational frequency spectrum. The apparatus has a housing assembly including a first end, a second end, and one or more protective enclosures configured to accommodate one or more devices. The housing assembly is configured to be rotationally registered to the structural member when coupled to the structural member, and is characterized by a predetermined housing mass. A spring arrangement is coupled between the structural member and the first end and/or coupled between the structural member and the second end in the operational state. The spring arrangement is characterized by a predetermined force-displacement relationship.

Abstract: Determining distance and direction from a first borehole to a second borehole including generating a time-varying magnetic field by axially reciprocating magnets of opposed polarity, at a first location in a second borehole, and detectable in the region of the first borehole. First and second sensors positioned at an observation point in the first borehole measure the amplitude and relative phase of components of the magnetic field. From these measurements, the direction, relative to the sensors, from an observation point to the first location is determined. The distance between these points is determined by measuring amplitude variations with depth of the magnetic field at observation points in the first borehole and computing theoretical variations in the amplitude for different assumed distances between the observation points and the location of the magnetic field source which are compared with theoretical variations to determine the distance between the first and second boreholes.

Abstract: The present invention is directed to tracking a borehole drilling direction and magnetic azimuth and orienting the tool face which controls the direction of drilling in a generally horizontal path between a specified borehole entry point and a predetermined exit location. The generally horizontal path may be disposed under a geographic obstacle such a river, a highway, a railroad, or an airport runway wherein the ground above the borehole is difficult or impossible to access.

Abstract: The present invention is directed to a system that has a first sensor assembly coupled to a mobile platform that traverses a predetermined subsurface path and has an axis of motion. The first sensor assembly obtains a gravity vector of the Earth relative to the mobile platform. A second sensor assembly is disposed in substantial alignment with a predetermined position relative to the axis of motion and is characterized by a sensitivity axis. The second sensor assembly provides a sensor signal substantially corresponding to a single vector component of the Earth's rotation vector. A control system is configured to derive the path direction relative to a known direction and an inclination angle of the mobile platform relative to the surface based on the gravity vector and the single vector component of the Earth's rotation vector.

Abstract: The present invention is directed to tracking a borehole drilling direction and magnetic azimuth and orienting the tool face which controls the direction of drilling in a generally horizontal path between a specified borehole entry point and a predetermined exit location. The generally horizontal path may be disposed under a geographic obstacle such a river, a highway, a railroad, or an airport runway wherein the ground above the borehole is difficult or impossible to access.

Abstract: The present invention is directed to a system that has a first sensor assembly coupled to a mobile platform that traverses a predetermined subsurface path and has an axis of motion. The first sensor assembly obtains a gravity vector of the Earth relative to the mobile platform. A second sensor assembly is disposed in substantial alignment with a predetermined position relative to the axis of motion and is characterized by a sensitivity axis. The second sensor assembly provides a sensor signal substantially corresponding to a single vector component of the Earth's rotation vector. A control system is configured to derive the path direction relative to a known direction and an inclination angle of the mobile platform relative to the surface based on the gravity vector and the single vector component of the Earth's rotation vector.

Abstract: A wireline apparatus for deep well measurements in a borehole being drilled includes a drill string having multiple drill pipe sections connected end-to-end, with at least one of the drill pipe sections being electrically conductive and isolated to provide an electrode section. A nonmagnetic drill pipe section is connected in the drill string below said electrode section, and a hydraulic motor having a rotatable drill bit carrying a drill bit instrument sub having a magnetic field sensing instrument package is connected to a lowermost end of the drill string. A wireline locatable within said drill string incorporates an electrode locatable within the drill pipe electrode section, and carries at its distal end a wireline instrument package that is locatable within the nonmagnetic drill pipe section to receive data representing magnetic field data from the magnetic field sensing instrument package.

Abstract: A downhole source of electrical power for drilling tools is driven by the rotation of a drillstring or, if the drillstring is not rotating, by the rotation of a drilling sub. The source consists of an alternator having a rotor made up of a series of coils that are mounted on, and spaced around the circumference of, a rotating drilling sub, and a stator made up of a multiplicity of permanent magnets also spaced around the circumference of the drilling sub. The stator is mounted on the drilling sub by means of bearings and incorporates a counterweight that holds the rotor relatively stationary with respect to the sub and with respect to the coils, so that rotation of the sub, either by rotation of the drillstring or by rotation of a drill motor in the drilling sub, produces relative rotation of the rotor and stator to generate an AC electrical output.

Abstract: A downhole source of electrical power for drilling tools is driven by the rotation of a drillstring or, if the drillstring is not rotating, by the rotation of a drilling sub. The source consists of an alternator having a rotor made up of a series of coils that are mounted on, and spaced around the circumference of, a rotating drilling sub, and a stator made up of a multiplicity of permanent magnets also spaced around the circumference of the drilling sub. The stator is mounted on the drilling sub by means of bearings and incorporates a counterweight that holds the rotor relatively stationary with respect to the sub and with respect to the coils, so that rotation of the sub, either by rotation of the drillstring or by rotation of a drill motor in the drilling sub, produces relative rotation of the rotor and stator to generate an AC electrical output.

Abstract: A pair of elongated crossed coils is deployed in a first borehole and an instrument containing magnetic field sensors is deployed in a second borehole. The crossed coils are energized in quadrature by AC currents producing a rotating, elliptically polarized magnetic field at the second borehole. Mathematical analysis of the magnetic field sensor readings determines the location of the second borehole relative to the first. Both the distance and the rotational direction to the second borehole are determined as a function of depth of the sensors relative to that of the pair of crossed coils. Twisting of the long coil in the borehole is evaluated and the relative distance between the boreholes and the corrections needed due to such twisting are determined.

Abstract: An apparatus and method for measuring the location of one borehole relative to another includes a pair of elongated crossed coils deployed in the first borehole and an instrument containing magnetic field sensors deployed in the second borehole. The crossed coils are energized in quadrature by AC currents producing a rotating, elliptically polarized magnetic field at the second borehole. Mathematical analysis of the magnetic field sensor readings determines the location of the second borehole relative to the first. Both the distance and the rotational direction to the second borehole are determined as a function of depth of the sensors relative to that of the pair of crossed coils. No knowledge or measurement of the rotational orientation of the crossed coil in the first borehole is needed.

Abstract: Electrically powered electromagnetic field source beacons installed in a reference well in combination with a down-hole measurement while drilling (MWD) electronic survey instrument near the drill bit in the borehole being drilled permit distance and direction measurements for drilling guidance. Each magnetic field source beacon consists of a coil of wire wound on a steel coupling between two lengths of steel tubing in the reference well, and powered by an electronic package. Control circuitry in the electronic package continuously “listens” for, and recognizes, a “start” signal that is initiated by the driller. After a “start” signal has been received, the beacon is energized for a short time interval during which an electromagnetic field is generated, which is measured by the MWD apparatus.

Abstract: Measurement of the location and direction of a drill head in a borehole extending beneath an obstacle such as a body of water utilizes a single AC solenoid at a known location but having an unknown orientation. The measurements are used to direct the path of the borehole.

Abstract: Measurement of the location and direction of a drill head in a borehole extending beneath an obstacle such as a body of water utilizes a single AC solenoid at a known location but having an unknown orientation. The measurements are used to direct the path of the borehole.

Abstract: An apparatus and method for surveying the path of a borehole includes three single-axis electromagnetic field sensors and three single axis gravity direction sensors in the borehole being surveyed. A pair of closely spaced, parallel guide wires carrying oppositely directed electric current in a reference borehole generate a known electromagnetic field, which is detected by the sensors. Mathematical analysis of electromagnetic and gravity measurements determines the lateral location and the direction of drilling in the neighboring borehole.

Abstract: An electromagnetic method and apparatus for directional drilling guidance of horizontal boreholes for the installation of pipelines and communication cables beneath rivers, highways and other obstacles is disclosed. A solenoid source, with horizontal axes, generates alternating electromagnetic fields which are measured in the borehole by a magnetometer with known orientation with respect to the direction of gravity near the drill bit. A preferred embodiment has a useable range of 150 meters from the source.

Abstract: Apparatus and Methods are disclosed for determining the direction between a rotating magnetic field and alternating magnetic field sensors at a remote location. The curvature of a borehole drilling assembly between a rotating drill bit carrying a permanent magnet and sensors behind a drilling motor is measured to provide early indication of changes in drilling direction. A second application concerns measurement of the convergence and divergence and the skewness of two approximately parallel well bores to provide information for correcting the drilling direction to maintain parallelism. A third application measures the direction and distance to a point target to provide data for guiding drilling toward that target. The primary apparatus are an oriented, rotating permanent magnet and an oriented, three component alternating magnetic field sensor.

Abstract: An electromagnetic method and apparatus for directional drilling guidance of horizontal boreholes for the installation of pipelines and communication cables beneath rivers, highways and other obstacles is disclosed. A solenoid source, with horizontal axes, generates alternating electromagnetic fields which are measured in the borehole by a magnetometer with known orientation with respect to the direction of gravity near the drill bit. A preferred embodiment has a useable range of 150 meters from the source.

Abstract: An electromagnetic method and apparatus for directional drilling guidance of horizontal boreholes for the installation of pipelines and communication cables beneath rivers, highways and other obstacles is disclosed. A solenoid source, with horizontal axes, generates alternating electromagnetic fields which are measured in the borehole by a magnetometer with known orientation with respect to the direction of gravity near the drill bit. A preferred embodiment has a useable range of 150 meters from the source.