Abstract: A system for guiding a well comprises a current source, a ground terminal electrically connected to the current source and grounded at the surface of the Earth, a reference wellbore comprising an intermediate casing (IC) that includes an IC electrical discontinuity and is electrically conductive between that the IC discontinuity and the IC bottom hole, a reference conductor electrically connected to the current source, a tubular that includes a tubular string electrical discontinuity (TSED), is electrically conductive between the TSED and the tubular bottom hole end (TBHE), and is inserted into the reference wellbore through the IC. Electrical connections exist between the tubular, the reference conductor, and the reference wellbore between the TSED and the TBHE, whereby current flowing through the reference conductor produces a magnetic field; magnetic sensors to sense the magnetic field and a guided wellbore is steered in response to the sensed magnetic field.

Abstract: A well completion system includes a current source, a ground terminal, and a reference conductor. The reference conductor is electrically connected to the current source, and is inserted into a reference wellbore having a tubular therein. The tubular has a tubular bottom hole end, and the tubular is electrically conductive between an electrical discontinuity and the bottom hole end. The tubular between the tubular string electrical discontinuity and the tubular bottom hole end is electrically connected to the reference conductor. The tubular between the tubular string electrical discontinuity and the tubular bottom hole end is electrically connected to the reference wellbore. Magnetic sensors are located outside the reference wellbore.

Abstract: An artificial toolface reference system includes a power supply providing current to a ground lead and a reference lead. A ground point is coupled to the ground lead and in electrical connection with the ground. A reference wellbore includes a reference conductor in electrical connection with the ground. The reference conductor is in electrical connection with the reference lead. A guidance sensor positioned outside the reference wellbore includes at least one magnetometer. The power supply may be used to provide a current through the reference conductor, the ground, and the ground point such that a reference magnetic field is generated along the reference conductor. The guidance sensor may measure the reference magnetic field with a magnetometer. An artificial magnetic toolface may be calculated therefrom.

Abstract: An artificial toolface reference system includes a power supply providing current to a ground lead and a reference lead. A ground point is coupled to the ground lead and in electrical connection with the ground. A reference wellbore includes a reference conductor in electrical connection with the ground. The reference conductor is in electrical connection with the reference lead. The reference conductor includes an uninsulated portion and an insulated portion having an insulating layer positioned thereabout. A guidance sensor positioned outside the reference wellbore includes at least one magnetometer. The power supply may be used to provide a current through the reference conductor, into the ground through the uninsulated portion, and the ground point such that a reference magnetic field is generated along the reference conductor. The guidance sensor may measure the reference magnetic field with a magnetometer. An artificial magnetic toolface may be calculated therefrom.

Abstract: A feedback-controlled force measuring apparatus with a force input element, a piezoelectric force generating element and a precision motion detection element in a feedback-controlled loop. Two embodiments are described. In one the force-generating element is a supported proof mass to sense linear acceleration, and in the other the force-generating element is a diaphragm supported to sense external pressure. The precision motion detection element employs resistance and inductance of a case-fixed coil of wire modulated by the distance from the coil to an electrically-conductive member connected to a force-generating element. The piezoelectric force generating element may be either a bimorph, or a piezoelectric stack.

Abstract: A printed circuit board (PCB) coil linear actuator is disclosed. The actuator includes a coil assembly and a magnet assembly. The coil assembly includes a plurality of PCB coils electrically connected in series. The PCB coils arranged in a row and adjacent PCB coils are separated by a gap. Each PCB coil includes a low aspect ratio, multi-layer coil member disposed on a board member. The actuator assembly includes a plurality of magnet units arranged in a row, wherein adjacent magnet units are separated by a gap. When the actuator is assembled, the PCB coils arranged in alternating sequence with the magnet units. The PCB coil linear actuator is intended to replace traditional slotted bobbin voice coil actuators (VCAs) and is particularly useful in fast steering mirror (FSM) applications. The PCB coil linear actuator provides many advantages over a VCA of an equivalent motor constant, including improved performance, lower weight and a lower profile.

Abstract: An MHD sensor/actuator is provided for generating torque as well as sensing angular displacements around a sense/torque axis. A column of conductive liquid which rotates within a circumferential channel having an inner circumferential surface and outer circumferential surface provides an inertial proof mass, the relative motion of which within the channel generates a torque or represents a sensed displacement about the common axis of the circumferential channel. According to certain embodiments, a cylindrical column of magnets are located coaxially with the circumferential channel to produce a radially oriented magnetic field which is perpendicular to the common axis. According to other embodiments, a magnetic ring is provided coaxially with the circumferential channel to produce a magnetic field in the direction of the common axis.

Abstract: A device providing an inertially stabilized laser beam as an optical reference. The device consists of a base and a small stabilized optical platform that emits the laser beam. The platform connects to the base through a mechanical flexure that allows relative motion in two axes. High-bandwidth angular rate sensors affixed to the platform measure platform motion in inertial space. Linear displacement sensors measure relative motion between base and platform. A closed-loop control system accepts these sensor measurements and command actuators that null the sensed platform motions, maintaining the optical platform fixed in inertial space. The digital controller implements a Sensor Blending Kalman Filter that blends high frequency signals from the platform with low frequency signals from a DC sensor (gyroscope) external to this device but affixed to the common base. The controller enables both stabilization of the laser beam and commanded pointing of the beam in inertial space.

Abstract: A downhole drill bit drive motor assembly which provides a bilateral low resistance path from the upper end of a downhole drill bit drive motor to the lower end of such a motor by employing an insulated wire or group of several wires through the rotor of the motor. The drive motors provide a drive torque to a drill bit based on the flow of drilling fluids through the motor and includes an outer case, a motor stator, a motor rotor, a coupling to connect the motor rotor to an output shaft and a bearing to support both axial and radial loads. Fixed electrical contacts are provided at the upper end of the drill bit drive motor to provide connection to wireline for transmission of data from that point to the surface or other higher points. Rotary electrical contacts that provide continuous electrical contact as a rotary portion rotates with respect to a stationary portion are provided at the upper, lower, or both ends of the rotor.

Abstract: A borehole instrument that detects the joints of successive axial lengths of magnetic material enclosing a borehole while traveling along the inside of the enclosure by detecting anomalous magnetic fields indicative of the enclosure's joints.

Abstract: A magnetohydrodynmic angular rate sensor is described. A housing supports first and second coaxial proof masses in respective annular channels, permitting relative motion between the axis of the proof masses and the housings. First and second magnets associated with each annular channel result in an electric potential being generated across each channel proportional to the relative circumferential velocity between the proof masses and the housing. The annular channels are connected together to form a continuous pumped fluid circuit which introduces a radial flow velocity in each channel. At low rotational frequencies, a circumferential velocity component is induced in the proof masses due to Coriolis acceleration which results in a measurable electrical voltage across the annular channels. The low frequency response of the sensor is therefor extended to lower frequencies.

Abstract: The present invention relates to a strut assembly which may be selectively projected and retracted with respect to associated structure of a solid or liquid propellant rocket of missile, with such structure comprising one of, for example, a nozzle thereof or the body thereof. The invention struct may be projected either internally of the nozzle or externally of the missile body, as desired. Projection and retraction of the strut are accomplished through use of fluid actuation means, the fluid mode of means of which comprises coolant which is also directed in various locations on the inventive strut assembly to cool the strut assembly and to protect it and adjacent structures from particulate impaction, heat and thermal damage, etc.

Abstract: An electronic motion sensor is described, wherein a cavity formed in a case of high flux density material supports a permanent magnet at the bottom. The permanent magnet has a north/south pole orientation in line with the cavity axis. A circular channel is located above, having an axis coincident with the cavity axis and which is filled with mercury. A center contact post is located long the cavity axis in contact with the mercury, extending upwards through the top of the channel. An amplifier circuit supported on a header of high flux density material is placed on top of the channel. The amplifier amplifies the potential difference between the center contact and the case. The header effectively seals the cavity of the case.

Abstract: Land vehicle navigation apparatus combining an inertial angular rate sensor having a sensitive axis, with an inertial acceleration or tilt sensor having at least two sensitive axes, these sensitive axes having a known relationship to the inertial angular rate sensor's sensitive axis. Also provided is circuitry to accept from an external source an initial input valve (or self initialization, by rotary multiple positioning) of the vehicle's azimuthal orientation angles, roll, pitch, and azimuth, with respect to an Earth-fixed coordinate set as the land vehicle travels over the Earth surface. Changes to the azimuth angle during travel are determined by integration of the output of the inertial angular rate sensor.

Abstract: A land vehicle navigation apparatus incorporates an inertial angular rate sensor on the vehicle and having a sensitive axis, and an inertial acceleration or tilt sensor having at least two sensitive axes; the latter two sensitive axes are typically located at the vehicle in a plane parallel to the Earth's surface; and a rotary drive is operatively connected to the sensors to rotate them about an axis extending generally at the vehicle in a plane parallel to the Earth's surface; and, circuitry is operatively connected with the sensors to determine three vehicle orientation angles, roll, pitch, and azimuth, with respect to an Earth-fixed coordinate set at a first location, and also to determine the three vehicle orientation angles as the land vehicle travels over the Earth surface; and changes to the azimuth angle during travel are determined by integration of the output of the rate sensor; also, the sensor, drive and circuitry are typically carried by the vehicle.

Abstract: A solid electrode in the core of an angular motion sensor has a body of conductive fluid confined therein within an annular flux gap between axially spaced magnets. An arrangement of slots in the walls of the electrode modifies the current, induced in the fluid by inertial displacement, into a circumferential component, which is inductively coupled to an output winding from which an output signal is obtained.

Abstract: A borehole survey apparatus includes an angular rate sensor, a tilt sensor, a rotary drive to rotate the sensors about an axis extending in the direction of the borehole, circuitry connected with said sensors to determine the azimuthal direction of tilt of the borehole at a first location therein, drive control circuitry and a switch operatively connected with the sensors whereby they may be connected in feedback relation with the rotary drive so that an axis defined by a support for the rate sensor is maintained at predetermined orientation relative to horizontal during travel of the apparatus in a borehole relative to the first location, and integration circuitry connected with the rate sensor whereby changes in borehole alignment during travel may be determined.

Abstract: A borehole survey apparatus including(a) angular rate sensor means having a sensitive axis,(b) tilt sensor means,(c) a rotary drive operatively connected to said (a) and (b) sensor means to rotate same about an axis extending generally in the direction of the borehole,(d) and circuitry operatively connected with said (a) and (b) sensor means to determine the azimuthal direction of tilt of the borehole at a first location therein, said (a) sensor means also connected in feedback relation with the drive whereby the sensitive axis of the (a) sensor means is maintained at a predetermined orientation relative to horizontal during travel of said apparatus in the borehole relative to said first location, and whereby changes in borehole alignment during said travel may be determined.

Abstract: A borehole mapping apparatus which employs a ring laser gyroscope. The path of the laser is defined by looping paths of laser beam travel having long and short stretches of travel. The ratio of the stretches being substantially greater than two.

Abstract: The invention relates generally to mapping or survey apparatus and methods, and more particularly concerns efficient transmission of survey signals or data from depth level in a borehole or well to the well surface, for analysis, display or recordation; further it concerns efficient transmission of command data from a surface computer unit to the survey tool at depth level in a borehole or well for control of instrumentation operating modes, operating characteristics, or diagnostic purposes; and further it concerns supply of DC power downwardly to the instrumentation via a wireline by which such command signal and survey data or signals may be transmitted upwardly or downwardly respectively.