Abstract: A method for determining the orientation of the axis of a borehole with respect to an earth-fixed reference coordinate system at a location in the borehole comprising the steps of: measuring two cross-borehole components or two-cross-borehole components and an axial component of the earth's gravity field at a location in the borehole; measuring two cross-borehole components of the earth's magnetic field; determining the inclination angle of the borehole axis from the gravity component measurements; determining the highside angle reference of the cross-borehole measured components of the earth's gravity and magnetic fields from the gravity component measurements; determining more than one individual estimate of the azimuthal orientation of the borehole axis from the inclination angle, the highside angle reference and the two measured cross-borehole components of the earth's magnetic field; determining an error indicative parameter for each individual estimate of the azimuthal orientation of the borehole axis;

Abstract: A method and apparatus is presented for determining the inclination angle of a borehole being drilled, the data for determining the inclination angle being obtained while the drillstring is rotating.

Abstract: A method and apparatus is presented for measuring the azimuth angle of a borehole being drilled, the data for determining the azimuth angle being obtained while the drillstring is rotating.

Abstract: An apparatus and a method for remotely inspecting the interior walls of a cavity having a circular cross section that varies in diameter, such as the interior of a hollow tube plug. The apparatus has an eddy current probe head having a distal and proximal end, wherein the distal end engages the cavity walls, an elongated support assembly connected to the proximal end of the probe that is insertable within the cavity, a radial extender mechanism for radially extending and withdrawing the distal end of the probe with respect to the longitudinal axis of the support assembly, and a probe driving and delivery system for inserting the support assembly into the cavity and helically moving the probe head to inspect the cavity walls for discontinuities.

Abstract: A method is proposed for better determining the azimuth and inclination of a borehole in which a priori information regarding the magnitude of the earth's gravitational field strength, its magnetic field strength and direction are utilized to constrain the measured components of the earth's gravitational and magnetic field vectors. The constrained fit method adjusts the accelerometer and the magnetometer tri-axis measurements to optimize agreement between the measured data and the a priori magnetic and gravity field strengths and the magnetic dip angle. The adjustment that is selected is that which produces the least increase in the statistical measure .chi..sup.2.

Abstract: Apparatus and method for establishing a level plane and with respect to the level plane, vertically aligning an acceleration sensitive axis of a gravity measurement device (10). The gravity measurement device includes an accelerometer (68), which is rotatably mounted on a gimbal shaft (62) within a gimbal frame (54). The gimbal frame is also rotatable about a longitudinal axis that is preferably oriented at a right angle to the longitudinal axis of the gimbal shaft. A stepping motor (20) is connected through an antibacklash gear (30), an idler gear (32) and an antibacklash gear (48) to a drive shaft (50). Rotation of this drive shaft causes the accelerometer to rotate about the gimbal shaft. In a similar fashion, a stepping motor (22) is drivingly connected to a drive shaft (56), used to rotate the gimbal frame.

Abstract: A pipeline bend detector pig for measuring the changes in direction of a pipeline having a first pig body assembly with an imaginary longitudinal axis and spaced apart resilient cups for supporting the pig body assembly in a pipeline so that the axis thereof is at least approximately the axis of the pipeline and for impeding flow of fluid past the pig so that the pig is propelled by fluid flow through the pipeline, and a second pig body assembly also having an imaginary logitudinal axis and means for support thereof within a pipeline so that the axis thereof is at least approximately the axis of the pipeline, a universal joint connecting the front end of the second pig body assembly to the rear end of the first pig body assembly and an integrator plate and finger assembly with the first pig body assembly arranged so that the fingers are deflected upon the deflection of the internal wall of the pipeline to thereby deflect an integrator plate, an instrument responding to the deflection of the integrator plate,

Abstract: A gauge for measuring in situ the diameter of a borehole in salt or other ft creeping rock types is provided so that changes in borehole structure can be detected. The gauge comprises a cylindrical body insertable lengthwise into a borehole and having an internal channel wherein sensors can be displaced outwardly when air is directed into the gauge, two air displacement sensors located in the channel having slotted keyways at their inner ends which form an orifice proportional to the distance between the sensors, a pneumatic device capable of providing a stream of air into the gauge body, and a flow meter for measuring air flow through the gauge body. The borehole diameter is determined by directing a stream of air into the gauge body and measuring the air flow which will be proportional to the distance between the sensors when displaced outwardly against the borehole walls. The gauge is advantageous in that it does not itself create artificial stresses or deformations in the borehole walls.

Abstract: An electro-mechanical eddy current probe having a rotatable sensing head for sensing the wall thickness of and locating local defects in a tube or conduit through which it is passed. The rotatable head includes a radially movable, outward projecting sensing member which is spring-biased into engagement with the interior surface of the tube and which carries an eddy current coil or which actuates either the core of a differential transformer, a strain gauge or a rheostat, each electrically monitored by the probe. The cylindrical probe is centered within the tube by a pair of centering guides at either of its ends. The probe also carries a fixed eddy current coil on its non-rotating body portion for detecting and anticipating locations of particular interest within the tube where the longitudinal movement of the probe should be slowed, such as locations of exterior tube support plates where denting is more apt to occur.

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 pipeline survey pig including an onboard inertial reference unit and signal processing units for receiving acceleration and angular velocity signals generated by the inertial reference unit, calculating resultant values of angular velocity and accelerations and averaging the calculated values to provide recordable signals related to the position of the pig and changes in curvature of the pipe. The pig is supported by a plurality of resilient cup shape support members which have a stiffness characteristic whereby the natural frequency of vibration which may cause lateral excursions of the pig is less than the signal generating rate yet greater than the frequency of the signal to be measured. The center of stiffness and the center of gravity of the pig are disposed along the central axis of the pig and the pipeline section being measured and are preferably coincident with each other.

Abstract: A pipeline pig device comprises a longitudinal housing of given length, having adjacent each end a substantially centralizing packer or seal by which pipeline fluids may be used to propel the device. Intermediate the longitudinal housing are a plurality of outwardly extending feeler arms which ride against the pipeline interior. Movement of the feeler arms caused by the pig traversing bends, miters or other deviations from straight, round pipe are transmitted to a recording system which, in combination with odometers, will provide information and/or changes in such bends.

Abstract: A method is presented, for use in borehole drilling, for correcting errors in azimuth determination resulting from variations in the earth's magnetic field to which a measuring instrument is exposed. The method distinguishes between variations in the earth's magnetic field caused by the drillstring and variation caused by external sources, and the method corrects only for errors caused by the drillstring. If the error is caused by the drillstring, an azimuth correction is made based on dip angle data, thereby reducing errors caused by scale factor variations since dip angle is a ratio quantity of magnetic field components.

Abstract: A method for determining the true dip and azimuth of bedding planes in a formation penetrated by a borehole using borehole televiewer measurements. The method corrects for borehole deviation and for inclination of the earth's magnetic field.

Abstract: A method for eliminating the influence of drill string magnetization on an azimuth measurement made by a magnetometer package disposed in the drill string. The method comprises first eliminating the influence of the cross-axial components of the drill string magnetization by taking magnetometer readings at various angular orientations of the drill string and then eliminating the influence of the axial component of the drill string magnetization.

Abstract: A pipe pig for traveling through a pipe line is supported on and moved by two or three runners, which also can move circumferentially on the inside of the pipe to alter the angular position of the runners with respect to the longitudinal axis of the pipe. In this way the runners, which support the pipe pig by contact with the inside surface of the pipe, may rotate so as to avoid obstructions as they are encountered. Such obstructions may take the forms of openings in the pipe wall or protrusions into the pipe from the pipe wall. Various devices may be used to detect the presence of such obstacles and to detect both the axial position and angular orientation of the pig within the pipe. The apparatus for changing the angular position of the runners may be integrated with or separate from the apparatus for moving the pig axially in the pipe.

Abstract: A borehole survey instrument has a probe with a polarized light system for transmitting a signal representing the angular orientation of the probe to the surface. Light from a source in the probe is directed through a polarized filter with an axis of polarization orthogonal to the longitudinal axis of the probe. The polarized light beam is transmitted to the surface through an optical fiber light conduit. The angle of polarization is detected with a rotating polarizing filter and provides a measure of the probe orientation. In surveying a borehole, azimuth is determined from inclinometer measurements. The probe orientation in vertical sections of the borehole is measured by the polarized light system. Two measures of borehole azimuth are combined, providing an improved measure of azimuth in boreholes near vertical and near horizontal.

Abstract: A scribing device and method for generating curves, the term "scribe" encompassing marking a groove on a surface such as with an awl or router, marking a surface with a writing instrument, or cutting into a surface such as with a jigsaw. In one embodiment, the scribing device comprises a generator and a scribing assembly. The generator has a generally flat, upper surface with a groove formed therein, the groove comprising one or more connected, linear or circular segments. The scribing assembly comprises a body having a lower tracing surface shaped to permit sliding movement over the upper surface of the generator. The scribing assembly also includes first and second tracers and means for mounting a scribing instrument. Each tracer includes a follower projecting downward from the tracing surface, and each follower is adapted to slide along the groove. The scribing assembly is moved such that the followers follow the groove, whereby the scribing instrument scribes the curve.

Abstract: An electro-mechanical eddy current probe having a rotatable sensing head for sensing the wall thickness of and locating local defects in a tube or conduit through which it is passed. The rotatable head includes a radially movable, outward projecting sensing member which is spring-biased into engagement with the interior surface of the tube and which carries an eddy current coil electrically monitored by the probe. The cylindrical probe is centered within the tube by a pair of centering guides at either of its ends. The probe also carries a fixed eddy current coil on its non-rotating body portion for detecting and anticipating locations of particular interest within the tube where the longitudinal movement of the probe should be slowed, such as locations of exterior tube support plates where denting is more apt to occur.

Abstract: A compass type instrument capable of describing curves, circles and ellipses of infinitely variable angle and size. The central column of the instrument is supported on a foot that aligns the instrument with the center of the desired ellipse and maintains the instrument still and perpendicular to the surface to be marked. Removably mounted on the central column is a circular cam that is hinged symmetrically along it's diameter. Non-circular symmetrically hinged shapes may be substituted to alter the curve. The extent that this cam is folded about itself is adjustable and determines the angle of the ellipse described. An articulated follower arm is adjustably mounted to the top of the central column. About the central column rotates the upper section of the follower arm that pivots at a point variable from the center of the column. The upper follower arm is spring loaded in order to keep contact with the cam.

Abstract: This invention relates to mapping or survey apparatus and methods, and more particularly concerns derivation of the azimuth output indications for such apparatus in a borehole from the outputs or output indications of either an inertial angular rate vector sensor (or sensors) and an acceleration vector sensor (or sensors), or a magnetic field vector sensor (or sensors), and from the outputs of an acceleration vector sensor (or sensors). At least one of such sensors in any instrument may be canted relative to the borehole axis. Borehole tilt is also derived.

Abstract: Apparatus and a method for detecting deflections along the length of a pipeline. A plurality of measurements of inertial attitude are made along the length of the pipeline over time by means of apparatus, including sensors, associated with a pipeline pig. Thereafter, by comparing a time sequence of such measurements, points of flexure are accurately located and identified.

Abstract: Bore-hole mapping, or surveying, or tool steering in a bore-hole is accomplished using selected combinations of sensors, with sensor signal compensation being provided, in the hole or at the surface. Typical sensors include an angular rate sensor or sensors, a linear acceleration sensor or sensors, and an angular acceleration sensor or sensors. The sensor group is typically rotated in the bore-hole, and the sensors may have selected sensitive axis angularity relative to the travel axis in the bore-hole.

Abstract: A transducer for sensing the angular position or rate of change of displacement of a housing of a borehole survey instrument with respect to a reference position includes a rotor magnetically suspended within a stator which is in turn secured to the housing. The rotor is constrained by the magnetic suspension to rotate about a single axis relative to the stator. A frame of reference is established for the transducer, against which subsequent measurements are compared. Optical sensing means are included for sensing the movement of the rotor about the axis of motion to develop an indication of the angular position or rate of change of position of the housing.

Abstract: An instrument including a gyroscopic rotor mounted to precess about a predetermined axis in response to pivotal movement of the rotor about a sensing axis, with the rate of precession being measured and being utilized to determine the amount of said pivotal movement above the sensing axis. Two or more such rotors precessing about different axes can respond to different components of the earth's rotational movement, or to other component movements or torques. Differences in the rates of precession of the two rotors indicate the relative strengths of the corresponding components of the earth's movement, and afford a basis for deriving an indication of azimuth.

Abstract: This invention relates to mapping or survey apparatus and methods, and more particularly concerns derivation of the azimuth output indications for such apparatus in a borehole from the outputs or output indications of either an inertial angular rate vector sensor (or sensors) and an acceleration vector sensor (or sensors), or a magnetic field vector sensor (or sensors), and from the outputs of an acceleration vector sensor (or sensors). Borehole tilt is also derived.

Abstract: A surface activated multishot survey tool utilizes a dampened magnetic compass movably positioned within a probe to determine the direction of a borehole. Lamps in the probe are operable to light the face of the compass. A lens projects the image of the compass onto a movable film strip. An electrical cable is connected to the probe and is used to pass a current to the lamps and provide selective operation of the tool from the surface of the borehole. Electrical connectors are provided at each end of the probe so that the probe may be inverted within the borehole to accommodate surveys in which the angle of the borehole is greater than that at which the compass will operate without error. Because connectors are located at both ends of the probe, electrical current passes around the magnetic compass, thus creating a magnetic field about the compass.

Abstract: A borehole survey method and apparatus for use in drilling substantially horizontal boreholes through a mineral deposit wherein a dip accelerometer, a roll accelerometer assembly and a fluxgate are disposed near the drill bit, which is mounted on a bent sub, and connected to a surface computation and display unit by a cable which extends through the drill string. The dip angle of the borehole near the drill bit, the azimuth of the borehole near the drill bit and the roll angle or orientation of the bent sub are measured and selectively displayed at the surface while the drill string is in the borehole for utilization in guiding the drill bit through the mineral deposit along a predetermined path.

Abstract: Illustrative embodiments of the present invention include methods and apparatus for processing measurements indicative of the dip and azimuth of formation features at various depths in a borehole to produce three-dimensional representations of the formation features. These three-dimensional representations may be in the form of two-dimensional presentations of apparent dip traces for various depths in one or more planes. The apparent dips may be varied with distance from the borehole in accordance with information derived from dips above and below a selected dip. The three-dimensional representations may also take the form of a contour map of a formation surface around the borehold which represents a three-dimensional structural model derived from dips above and below the contoured formation surface.Dip and azimuth variations over a given interval are used to define a family of surfaces in a three-dimensional reference system.

Abstract: A system for inspecting the relatively long, thin-walled, small-bore tubes of a heat exchanger provided with support plates for holding the tubes in predetermined positions, comprising a composite scanner having a plurality of flexure springs contacting the interior surface of a tube for detecting and profiling tube abnormalities as the scanner traverses the tube and an eddy current sensor incorporated in the scanner for generating a unique signal as the scanner passes a contiguous support plate to assist in the accurate location of tube abnormalities.

Abstract: The disclosure relates to a tool for borehole logging comprising a plurality of extendable caliper arms to determine borehole contour.

Abstract: A method of measuring the deviation of the run of the actual vertical center axis of fluid filled bore holes and trenches relative to the direction of the design center axis thereof which bore holes and trenches are excavated under bentonite slurry comprises inserting into said bore holes and trenches a gauge means suspended from a cable means, whereby said gauge means is arrested inside said bore hole at any desired level, and thereafter a measuring cable means is connected to said gauge means and substantially tensioned and brought to run in an exact vertical direction whereupon above ground level the horizontal deviation of said cable means from the design center line of said bore hole or said trench is measured.

Abstract: Mapping apparatus comprises:(a) a gyroscope and a carrier frame therefor,(b) the gyroscope characterized as having a spinning rotor and torsion structure defining a gimbal, and wherein the rotor spin frequency has a predetermined relation to a resonant frequency of said structure,(c) the gyroscope further characterized as having two input axes, and an output axis about which the spin rotor rotates,(d) drive means operatively connected with said frame to rotate the frame about one of said axis, and(e) the gyroscope having means to detect rotor pivoting about one of said two input axes in response to said rotation of the frame.A second gyroscope may be employed, with its frame. rotated by the same drive means; and the output axes of the two gyroscopes are typically orthogonally related.

Abstract: The invention contemplates use of a single magnetic-field (flux) sensor mounted within an elongate probe housing, to continuously generate telemetered electric signals from which the instantaneous orientation of the housing is at all times known and from which changes in orientation may be tracked as a function of probe depth within the borehole in which the probe housing may be displaced. The telemetered electric signals provide accurate and current indications of (a) magnitude of the horizontal component of the earth's magnetic-field lines, (b) direction and magnitude of probe-axis tilt with respect to the gravitational vertical, and the direction of the earth's magnetic field, and (c) a probe-housing frame-angle reference; provision being made within the probe housing for performing substantially all discriminating, detecting and other problem-solving functions, whereby the telemetered signals are directly utilizable by recording and/or display equipment at surface end of the borehole site.

Abstract: A mandrel for hydraulically expanding tubes into engagement with a tubesheet, the body of the mandrel being coated with an electrically isolating impermeable membrane and having an eddy current coil adjacent the leading end thereof, the tube into which the mandrel is placed and the body of the mandrel serving as leads for operating the eddy current coil in order to determine when the leading end of the mandrel is adjacent the inner edge of the tubesheet and a mandrel having a portion formed from wire rope so that the mandrel is flexible and can fit into a tube adjacent a hemispherical head.

Abstract: A bottom hole survey apparatus is characterized by a survey instrument having a reference line therein, the instrument being receivable by the engagement of flanges provided along the instrument into keyways provided on the interior of a non-magnetic instrument barrel. When engaged, the reference line of the survey instrument is disposed in a predetermined angular relation with respect to the barrel. The barrel has means provided on the exterior thereof for receiving a visual sighting element thereon, the sighting element being in a predetermined angular relationship with respect to the reference line. At least one non-magnetic spacer element is connectable to the barrel, the spacer element being provided with an adapter having a T-shaped head thereon which is received within a corresponding T-shaped groove provided at the lower end of the instrument.

Abstract: This is an invention in a method for locating the azimuthal direction of fractures induced into an underground formation adjacent to a well bore. Practicing the method of the invention involves measurement of stresses created at or near ground surface by such fracture propagation, utilizing pressure sensitive devices making up stress meters which reflect those stress changes on standard pressure gauges. Such stress meters are preferably each placed at an optimum distance from a well bore and spaced therearound, and, when a fracture is induced in the formation around the well bore, preferably by hydraulic means, said stress meters measure surface stress changes as horizontal pressure changes, which pressure change measurements can then be used to mathematically determine the direction of the fracture.

Abstract: A method of using an impression element to determine the actual size of a flow opening in a tubular member located in a well by comparing an extrusion formed on the impression element with calibrated data on extrusion size vs. actual hole size.

Abstract: For the directional drilling of boreholes, the orientation or roll angle of the drill head or mud-motor in the borehole has to be ascertained for steering purposes. The roll angle is determined, during drilling, by sensing at the location of the drilling tool in the borehole the values of the earth's magnetic field strength in two axes transverse to the main tool axis, signalling these values to the drilling station and translating them according to the direction and inclination of the borehole axis, which are known and normally updated at intervals between drilling runs. The down-hole assembly, located in a fixed attitude to the mud-motor, requires only static magnetic sensors. A resolver in a surface indicating unit provides for the indication of the roll angle as the angle determined by the sensors, translated according to the borehole information by the addition of an angle precalculated and selected from tables, calculated in a computation center, or calculated by computation in the indicating unit.