Abstract: A sensor deployment system includes a first bulkhead arranged at a first end of a downhole tool, a second bulkhead arranged at a second end of the downhole tool, opposite the first end, a first pivot block arranged proximate the first bulkhead, a second pivot block arranged proximate the second bulkhead, and an arm rotatably coupled to the first and second pivot blocks at opposite ends of the arm. Rotation of at least a portion of the arm drives at least a portion of the arm radially outward from an axis of the downhole tool.

Abstract: A downhole tool can include a photon beam source configured to transmit a photon beam into materials lining a wellbore. The materials may comprise fluid, casing, and cement. A photon detector in the tool is configured to count detected photons received at a predetermined angle from the materials. The density of the borehole material may be determined in response to the number of detected photons. Changes in a distribution of a plurality of photon count ratio values may indicate the standoff distance. Additional apparatus, systems, and methods are disclosed.

Abstract: A method for monitoring fluid flow in a conduit comprises: acoustically coupling an optical fiber to the conduit adjacent one or more flow restrictions (R1-R4) in the conduit; inducing a Distributed Acoustic Sensing (DAS) assembly to measure an acoustic noise signature (SNR1-4) generated in the fiber by the fluid flowing through each flow restriction (R1-R4); deriving the fluid flow rate of the fluid (QI, QI+II) flowing through each flow restriction (R1-R4) from the measured acoustic noise signature (SNR1-4); and displaying the derived fluid flow rate (QI, QI+II) at a fluid flow rate monitoring display.

Abstract: A gripper mechanism for a downhole tool is disclosed that includes an eccentric linkage mechanism. In operation, an axial force generated by a power section of the gripper expands the linkage mechanism, which applies a radial force to the interior surface of a wellbore or passage. A sliding portion allows the gripper to slide along a surface of the formation in response to the radial force applied to the interior surface of the wellbore or passage.

Abstract: A position sensor for well tools. A position sensor includes an indicator portion including a carrier supporting a resistive element and at least one contact, and a support device for supporting the carrier. Another position sensor includes an indicator portion including a slider for displacing at least one contact relative to a resistive element, the slider being displaceable between first and second limits, and an end load mechanism including a biasing device which exerts a biasing force on the slider as the slider approaches at least the first limit. Another position sensor includes an indicator portion including a resistive element and at least one contact which contacts and displaces across the resistive element, a change in position of the contact relative to the resistive element being indicated by a resistance change as the contact displaces across the resistive element.

Abstract: The system for the inspection and imaging of insulated pipes and vessels using backscattered gamma radiation and X-ray fluorescence includes a frame having a pair of coaxial rings adapted for coaxial mounting about the insulated pipe, vessel or the like. A pair of rotating supports are rotatably mounted within the pair rings for driven rotation thereof. A plurality of horizontal supports are secured to, and extend between, the pair of rotating supports such that each of the horizontal supports extends along a direction parallel to an axis of the insulated pipe. A plurality of inspection modules are slidably mounted to the horizontal supports. Each inspection module includes at least one radiation source, an X-ray fluorescence detector and a backscattered gamma radiation detector. The plurality of inspection modules are linearly translated along the axial direction of the pipe, and also circumferentially rotated therearound for simultaneous, three-dimensional inspection of the pipe body.

Abstract: Proppant placed in a subterranean fracture zone is detected with a spectral identification method in which capture gamma ray spectra are obtained during a logging run carried out with a logging tool having a neutron emitting source and at least one detector sensitive to thermal neutron capture gamma rays. Capture gamma rays from one or more high thermal neutron cross-section materials in the proppant are distinguished from capture gamma rays produced by thermal neutron capture reactions with other downhole formation and borehole constituents utilizing a spectral processing/deconvolution technique. The capture gammas rays from the high thermal neutron capture cross section material in the proppant are used to identify propped fracture zones either alone or in combination with other proppant identification methods which rely on measuring thermal neutron related count rates and/or thermal neutron capture cross-sections from neutron, compensated neutron, and/or pulsed neutron capture logging tools.

Abstract: A method for obtaining information about a subsurface formation from acoustic signals that contain information about to the subsurface formation, comprises: providing a fiber optic having a proximal end and a remote end, with the proximal end being coupled to a light source and a proximal photodetector, wherein said fiber optic cable includes randomly spaced impurities and selectively placed Bragg gratings and wherein the fiber optic cable is acoustically coupled to the subsurface formation so as to allow the acoustic signals to affect the physical status of at least one grating: transmitting at least one light pulse into the cable; receiving at the photodetector a first light signal indicative of the physical status of at least one first section of the cable, and outputting at least one item of information to a display.

Abstract: A method for obtaining information about a subsurface formation from acoustic signals that contain information about to the subsurface formation, comprises: providing a fiber optic having a proximal end and a remote end, with the proximal end being coupled to a light source and a proximal photodetector, wherein said fiber optic cable includes randomly spaced impurities and selectively placed Bragg gratings and wherein the fiber optic cable is acoustically coupled to the subsurface formation so as to allow the acoustic signals to affect the physical status of at least one grating: transmitting at least one light pulse into the cable; receiving at the photodetector a first light signal indicative of the physical status of at least one first section of the cable, and outputting at least one item of information to a display.

Abstract: A sensor for measuring at least one of temperature and pressure in a borehole, the sensor including a mixing medium disposed in a housing adapted for insertion into the borehole, the mixing medium exposed to at least one of the temperature and the pressure; wherein the mixing medium is used for four wave mixing of light to provide a signal that indicates at least one of the temperature and the pressure.

Abstract: Apparatus and method for detecting subsurface radiation phenomena. An elongated support member, adapted for disposal within a wellbore traversing a subsurface formation, includes a recess along its longitudinal axis. A pad is linked to the support member. The pad is configured with a surface correspondingly shaped to fit in juxtaposition with the support member recess. The pad is adapted for movement into and out of the recess such that an exposed surface of the pad can extend away from the support member. The pad also includes one or more radiation detectors and is adapted with shielding material on its sides near the exposed surface to prevent radiation reflected from the recess from reaching the detector(s) from the area near the exposed surface.

Abstract: Apparatus and method for detecting subsurface radiation phenomena. An elongated support member, adapted for disposal within a wellbore traversing a subsurface formation, includes a recess along its longitudinal axis. A pad is linked to the support member. The pad is configured with a surface correspondingly shaped to fit in juxtaposition with the support member recess. The pad is adapted for movement into and out of the recess such that an exposed surface of the pad can extend away from the support member. The pad also includes one or more radiation detectors and is adapted with shielding material on its sides near the exposed surface to prevent radiation reflected from the recess from reaching the detector(s) from the area near the exposed surface.

Abstract: A system for handling a radioactive source includes a container containing a radioactive source and a cap mounted on the container to retain the radioactive source inside the container. The cap has a first locking structure and a second locking structure. The system further includes a handling tool having a support shaft, a first locking tip adapted to form a first lock with the first locking structure, and a second locking tip adapted to form a second lock with the second locking structure. The first and second locking tips are slidably coupled to the support shaft.

Abstract: The present invention describes a unique method and apparatus for applying near-infrared spectroscopy to estimate weight percent of methane in crude oil from which one can then infer gas-oil ratio (GOR) of crude oils downhole in real time while collecting a fluid sample. The correlation equations provided by this invention use two wavelengths, one centered at 1670 and the other centered at 1682 nm. Both wavelengths are primarily sensitive to the methane peak absorption. To significantly improve the fit, non-spectroscopic parameters, such as temperature or pressure, can be included in the correlation equation. Also, this invention can be used to monitor sample cleanup by monitoring the increase in GOR associated with cleanup as a fluid being pumped from the formation transitions from mostly gas-free filtrate to mostly gas-containing crude oil.

Abstract: A wireline logging sonde for sensing fluid properties in a bore hole. The sonde has a main body and a plurality of sensor capsules mounted peripherally to the main body on fingers. A sensor element is located in each sensor capsule. The sensor elements receive power by inductive coupling from the main body and transmit data signals at radio frequencies back to the main body.

Abstract: In an apparatus and method for actuating arms used on a borehole data-logging tool to deploy measuring instruments against a borehole wall, a mandrel is provided. At least one arm carried by the mandrel is mounted to the mandrel to move between an expanded position, in which a part of the arm projects from the mandrel, and a retracted position. A resilient biassing compression spring provides a resilient biassing force on each arm for biassing the arm towards its expanded position. A hydraulic piston and cylinder assembly associated with each arm restrains the arm against movement towards its expanded position. A drive piston and cylinder assembly acts upon the resilient biassing compression springs for adjusting the resilient biassing force acting upon each arm.

Abstract: The acoustic impedance of a fluid in a borehole is determined by gating a reflected acoustic signal into a plurality of time slots, and comparing received energies of the signal for the time slots to obtain a value indicative of the acoustic impedance of the fluid. The value may be normalized to yield the acoustic impedance of the fluid using the acoustic impedance of, e.g., water as a calibration point. The acoustic pulse may be generated using a transducer immersed in an intermediate fluid contained within a chamber defined in part by a plate in contact with the borehole fluid and having a thickness such that a mechanical resonance frequency of the plate in a thickness mode is substantially equal to a resonance frequency of the transducer. The sonic velocity of the fluid is also measured and, when combined with the acoustic impedance, is used to determine fluid density.

Abstract: A well logging device of compact reduced diameter compared to the prior art, such well logging device having both short spaced and long spaced types of gamma ray crystal detectors installed in a measurements skid that comprises a relatively small diameter device constructed to withstand high temperatures and pressures, this device comprising a continuous stainless steel tube which provides pressure resistance and also allows low energy gamma ray transparency via large and small windows. This elongate type of stainless steel skid tube is furthermore internally supported by an internal tungsten tube placed therewithin, while the skid design also includes means for pressing the skid tube against a borehole wall so as to obtain more accurate formation density measurements downhole.

Abstract: A method of locating in situ hydrocarbons in underground formations comprises illuminating the borehole wall with light such as visible, infrared or ultraviolet light or combinations of these, from a source in a tool such as a wireline logging tool or an LWD tool, detecting any fluorescent radiation with a detector in the tool and analyzing the florescent radiation to determine the presence of hydrocarbon in the formation. The tool is moved through the borehole while irradiating the formation and detecting fluorescence. The borehole wall is illuminated and fluorescence detected through a window in the tool which is pressed against the borehole wall with sufficient force to displace any mudcake. The window is made of a wear resistant material such sapphire or diamond and is conveniently secured in a wear resistant housing which might be made of tungsten carbide or the like.

Abstract: The present invention features an apparatus comprising a packer means and a packer pressure sensing means. The packer means inflates to isolate zones in a well, such as an oil well or a gas well. The packer means responds to a material for inflating and providing a packer inflation pressure. The packer pressure sensing means responds to the packer inflation pressure, for providing a sensed packer inflation pressure signal containing information about a sensed packer inflation pressure when the packer is inflated to isolate zones in the oil or gas well. The packer pressure sensing means may include an internal fiber optic Bragg Grating sensor arranged inside the packer means, for providing the sensed internal packer inflation pressure signal. The packer pressure sensing means may also include an external fiber optic Bragg Grating sensor arranged outside the packer means, for providing the sensed external packer inflation pressure signal.

Abstract: A method of locating in situ hydrocarbons in underground formations comprises illuminating the borehole wall with light such as visible, infrared or ultraviolet light or combinations of these, from a source in a tool such as a wireline logging tool or an LWD tool, detecting any fluorescent radiation with a detector in the tool and analyzing the florescent radiation to determine the presence of hydrocarbon in the formation. The tool is moved through the borehole while irradiating the formation and detecting fluorescence. The borehole wall is illuminated and fluorescence detected through a window in the tool which is pressed against the borehole wall with sufficient force to displace any mudcake. The window is made of a wear resistant material such sapphire or diamond and is conveniently secured in a wear resistant housing which might be made of tungsten carbide or the like.

Abstract: A method/apparatus for determining the density of a formation traversed by a borehole having irregularities along the borehole wall preferably employs/includes a housing, a photon source, and a detector. The source preferably includes an irradiation path extending from the source to a side of the housing. Similarly, the detector preferably includes a detection path extending from the detector to the side of the housing. A stylus may be mounted onto the housing for penetrating through a layer of mudcake. Such stylus preferably includes a base and a substantially small contact head having a window fixedly attached thereto. A second irradiation path may extend from the base to the contact head. A second detection path may also extend from the base to the contact head. The irradiation and detection paths in the stylus are preferably substantially aligned with respective irradiation and detection paths in the housing.

Abstract: Images of rock formations below the earth's surface can be obtained on a microscopic scale. A borehole tool uses a seal to isolate an interval of the formation from borehole fluids which are outside the seal. A probe of the tool engages a wall of the formation and then draws formation fluid from the formation into the interior of the tool. The tool then produces an optical image of the formation which indicates rock texture. The seal can comprise a pad, inflatable packers, compressional packers, or cement plugs. The images of the formation can be obtained with electro-optic imagers such as charge-coupled devices (CCD) or a camera operating in the visible and/or near infrared range, or with ultrasonic transducers operating in the sub-MHz to mid GHz range, for example. The near infrared range provides an optical image of the formation through opaque fluids such as oil based muds or oil itself.

Abstract: The invention is a system for determining the epithermal neutron decay rate of an earth formation penetrated by a wellbore.

Abstract: An eccentric fluid displacement sleeve is disclosed for use with a measurement-while-drilling instrument, to convert the instrument for use in different size boreholes. The sleeve is made eccentric by either increasing or decreasing the thicknesses of positioning blades on the periphery of the sleeve, while maintaining the thickness of the fluid displacement blade aligned with the detectors.

Abstract: This disclosure provides a method for measuring the velocities of water volumes flowing co-directionally in separate conduits nested such as in injection or production well-bores. The method allows an oxygen activation measurement of the velocity of the water flow in the tubing-casing annulus in the presence of water flowing in the tubing string in the same direction. The method allows continuous logging at variable or constant cable velocities or stationary logging. Based on the method of velocity gauging, the method isolates the signal from the annular flow and can produce a continuous log of linear and volumetric annular flow rates with depth.

Abstract: A device for detecting radiation within a pipe having one or more carriages adapted for movement through the pipe. A set of radiation sensors is mounted on each carriage for detecting radiation on the interior of the pipe. The radiation sensors are positioned to cover a complete circumferential strip on the pipe interior while maintaining the geometry required to meet U.S. government criteria for the unconditional release of the pipe. Readings from the radiation sensors are transmitted out of the pipe and recorded to establish a detailed radiological survey of the pipe interior.

Abstract: A borehole logging tool is lowered into a borehole traversing a subsurface formation and a neutron detector measures the die-away of nuclear radiation in the formation. Intensity signals are produced representing the die-away of nuclear radiation as the logging tool traverses the borehole A signal processor, employing at least one neural network, processes the intensity signals and produces a standoff-corrected epithermal neutron lifetime signal to correct for standoff from the borehole wall encountered by the detector as the logging tool traverses the borehole. The signal processor further generates a porosity signal from the standoff-corrected epithermal neutron lifetime signal derived from measurements in borehole models at known porosities and conditions of detector standoff. A log is generated of such porosity signal versus depth as the logging tool traverses the borehole.

Abstract: The present invention is a formation compensated fluid density meter which includes a well logging sonde that is inserted into a borehole traversing an earthen formation. The sonde includes within it a source which emits gamma rays into the borehole fluid and formation partially collimated and detector assemblies which detect returning gamma rays and provide count signals corresponding to a count of the detected gamma rays. A cable connected to the detector assembly conveys the count signals to the surface where surface electronics includes apparatus which processes the count signals to provide a signal corresponding to the density of the fluid in the borehole.

Abstract: The apparatus includes a pad (20) pressed against the wall of a borehole (12), the pad comprising a plurality of detecting devices (42, 43, 44, 45) disposed in alignment along the longitudinal direction of the borehole. Each detecting device includes a housing (112, 113) having complementary ends fitted with electrical connectors. The end of one housing (112) is extended by first skirts (117, 118) suitable for interfitting between second skirts (121) of the complementary end of the housing (113) of an adjacent detecting device. An annular element (111) and screws (120, 122) fixed to complementary ends together thus constituting a rigid pad (20) which can be disassembled.

Abstract: A radioactive energy detector for well logging utilizes a Dewar flask. The Dewar flask has an inner housing containing a gamma ray detector. An outer housing surrounds the inner housing, with the annular clearance being evacuated. A window section is integrally formed in the side wall of the outer housing. The window section has a wall thickness that is less than the wall thickness of the side wall of the outer housing. The outer housing is constructed of a material of relatively low atomic number.

Abstract: A carrier apparatus for a radioactive well logging instrument is disclosed that includes an elongated generally cylindrical tool body adapted for wireline suspension within a well borehole and mounting an elongated sensor pad assembly carrying a radioactive source and at least one detector and adapted for a nesting fit with the tool body. Knuckle joint links mounted on the tool body engage opposite ends of the sensor pad for laterally extending the pad assembly from the tool body into contact with the borehole wall. The knuckle joint links provide independent preselected force loading to each end of the pad assembly and permit articulation of the pad assembly with respect to the tool body axis for maintaining the sensor pad assembly in contact with the borehole wall under rugose conditions.

Abstract: A seismic array system for receiving seismic signals at spaced-apart points in a wellbore is deployable on coiled tubing from the surface through an isolator apparatus mounted on the wellhead. The array includes spaced-apart geophone sondes which have hydraulic actuators for extension of sonde support pads into engagement with the wellbore wall. Each sonde has a hydraulic control unit for controlling operation of the hydraulic actuator to extend or retract the pads and for preliminary processing of signals received through the geophones of each sonde. Hydraulic fluid and electrical control signals are communicated through the coiled tubing from the surface. A signal processing unit is deployed at the upper end of the array string for final or intermediate processing of the geophoen signals from each sonde.

Abstract: A coiled tubing injection unit for injecting a continuous length of coiled steel tubing into a wellbore for performing well operations includes an x-ray inspection apparatus arranged to continuously monitor the wall section of the tubing as it is inserted into or withdrawn from the well to detect structural defects in the tubing. An x-ray source and detector unit are mounted in a housing which is supported for rotation about the longitudinal axis of the tubing for projecting an x-ray image through suitable processing and display apparatus. The x-ray detection unit may be mounted on a level wind mechanism of the coiled tubing storgage spool or at another point between the storage spool and the wellhead into which the tubing is being injected.

Abstract: A borehole logging tool is lowered into a borehole traversing a subsurface formation and a neutron detector measures the die-away of nuclear radiation in the formation. A model of the die-away of nuclear radiation is produced using exponential terms varying as the sum of borehole, formation and thermal neutron background components. Exponentially weighted moments of both the die-away measurements and die-away model are determined and equated. The equated moments are solved for the ratio of the borehole to formation amplitude components of the measurements. The formation decay constant is determined from at least the formation and thermal neutron background terms of the weighted measurement and model moments. The determined borehole to formation amplitude ratio is used to correct the determined formation decay constant for the effects of detector standoff from the borehole wall.

Abstract: Methods and apparatus for directly and more accurately assaying radiological characteristics of elements with a subsurface formation surrounding a bore hole. An instrument is provided which comprises a pulsed neutron source, a high resolution gamma ray detector and means for isolating a portion of the instrument in a neutron absorbing envelope comprised of a solution of fresh water and a neutron absorbing substance. This isolation means eliminates deleterious bore hole effects and maximizes the measurement of formation capture gamma rays. The applications of the present invention include measuring the presence of an element and measuring the ratio of two elements within a formation surrounding a bore hole.

Abstract: The porosity of an earth formation is derived in a plused neutron logging tool by use of a directionalized and borehole-shielded eptithermal neutron detector array and by processing detector count rate measurements of the epithermal neutron die-away curve in accordance with a multi-parameter fit to obtain as one parameter the epithermal neutron decay time of the formation and as a second parameter an indication of detector standoff (environmental) effects. The multi-parameter fitting procedure separates the formation and standoff effects on the measured count vs time curve, and yields a decay time measurement that is primarily representative of formation porosity and substantially free of environmental effects. To enhance count rate statistics, the neutron source and one or more of the epithermal neutron detector may be located at the same depth in the borehole. The neutron burst centroid is monitored an used to define a fiducial window for processing the die-way curve data.

Abstract: The present invention is a density meter which includes a well logging sonde that is inserted into a borehole traversing an earthen formation. The sonde includes within it a source which emits gamma rays into the borehole fluid and a detector assembly which detects gamma rays from the borehole fluid and provides a count signal corresponding to a count of the detected gamma rays. A caliper is also located in the sonde and it continually measures the diameter of the borehole as the sonde moves through the borehole and provides a caliper signal corresponding to the diameter measurement. A cable connected to the detector assembly and to the caliper conveys the count signal and a caliper signal to the surface where surface electronics includes apparatus which processes the count signal and the caliper signal to provide a signal corresponding to the density of the fluid in the borehole.

Abstract: In order to increase the angular field of observation of a logging sonde usable, in particular for dip metering, the sonde is equipped with measuring pads each comprising two independent flaps. The flaps of the same pad are hinged to a central element which is held permanently parallel to the axis of the sonde body, and they are applied against the wall of a borehole by blade springs. Each of the flaps carries an array of electrodes. The flaps of each of the measuring pads are circumferentially offset relative to each other so that the angular field of observation is increased without increasing the diameter of the sonde, once the pads have been retracted.

Abstract: A borehole logging tool for neutron lifetime logging of subterranean formations surrounding a borehole includes a pulsed source of fast neutrons and a radiation detector for measuring neutrons returning to the borehole from the irradiated formations surrounding the borehole. The radiation detector system comprises a neutron absorbing and gamma ray radiating material which is moved by an articulating arm into contact with the borehole wall and is azimuthally oriented so that such neutron absorbing and gamma ray radiating material is firmly pressed against the formation. A shielding material minimizes absorption of neutrons from the borehole fluid. A gamma ray detector located in the main body of the logging tool detects gamma rays from the radiating material as a measure of the epithermal or thermal lifetime characteristic of the formation adjacent the borehole.

Abstract: An apparatus is described for urging the measuring pad of a well logging sonde into engagement with the wall of a borehole. A relatively long primary arm on which the pad is mounted includes an actuator, and is pivotally connected to the body of the well logging sonde by a member extending therefrom. A backup arm is pivotally mounted on the extension member and biased outward from the logging sonde by suitable resilient means. The backup arm also is positively connected to a displacement member associated with the actuator. The primary and backup arms are cooperatively withdrawn into the body of the logging sonde by operation of the actuator. Moreover, the logging sonde is made eccentric in the borehole by suitable resilient means connected between the extension member and the sonde body.

Abstract: As the outrigger arms of a borehole logging tool are flexed inwardly and outwardly according to the diameter of the borehole opening through which they pass, the corresponding axial displacements of the ends of the arms are controlled to determine the axial positions of the arms relative to the tool. Specifically, as the arm ends move, they are caused to rotate by a cam mechanism. The stiffness of the arms causes the arm ends to rotate in unison, and the exact positions of the arms on the tool are then controlled by the differential movements of the arm ends in the cams.

Abstract: An improved radioactivity well logging sonde for sensing fluid flow in an earthen formation from a borehole traversing the formation in which the borehole also contains salt water includes a neutron source for irradiating the earthen formation with neutrons and a detector assembly which detects gamma radiation from the earth formation. The sonde also includes circuitry which processes pulses from the detector assembly to be provided uphole by way of a well logging cable. The sonde includes apparatus spatially arranged with the detector assembly which displaces salt water in the borehole so that there is substantially no salt water between the side of the borehole and the detector assembly. The improved well logging sonde also permits vertical fluid flow measurements in an earthen formation as well as the conventional horizontal fluid flow.

Abstract: Disclosed is an improved compensated density well logging apparatus which provides a mechanical linkage driven by an electric gear motor for extension of a thin cylindrical pad containing radioactive source and detection equipment exteriorly of the tool housing so as to penetrate the filter cake and eliminate or reduce the distorting effect of the filter cake and well bore fluid. A spring biased caliper arm is used to justify the tool and extended pad against the side of a well bore during measurement. The linkage supporting and positioning the caliper arm includes a pivot pin which extends exteriorly of the tool housing to engage two parallel aligned guide wheels riding in grooves formed exteriorly in the tool housing so as to reduce friction and prevent lateral movement of the linkage. This provides for a more accurate reading of the variable thickness of the filter cake and well bore diameter at varying depths within the well bore.

Abstract: An elongated body member having a plurality of crank arms pivotally attached thereto, such crank arms disposed generally symmetrically around the perimeter of the body member. At a first end of each crank arm is a contact pad for maintaining substantial contact with the sidewalls of a borehole. The second end of each crank arm is pivotally coupled to a drive link which is in turn attached to a piston which is longitudinally slidably mounted within the body member. Longitudinal movement of the piston within the body member will result in a corresponding generally lateral movement, either extension or retraction, of the crank arms and thereby of the contact pads attached thereto. A mechanism is provided for allowing the piston to traverse a limited range of longitudinal movement within the body member, a force being exerted upon the piston such that the piston is urged to the bound of such travel which will yield the maximum lateral extension of the contact pads.

Abstract: The instrument and method locate anomalies and the interface between two materials having little difference in their density in a mining or storage well. More particularly, the method comprehends the generation of gamma rays and the detection of scattered rays at a point spaced from the point of generation of the gamma rays. By moving the points of generation and detection through the well, there will be observed a pronounced change in the detection rate of the scattered gamma rays when various interfaces and anomalies are traversed.The focus interface instrument includes a decentralizer, collar locator, electronics assembly, detector, and radiation generator, all enclosed in a nonmagnetic stainless steel housing except for the electronics assembly whose housing is made of tubular steel. The radiation generator has a radioactive source which emits gamma rays, and the detector detects those rays reflected back to the detector.

Abstract: A technique for determining the density of an earth formation with a logging sonde including a gamma ray source and two gamma ray detectors spaced at different distances from the source is disclosed. The count rate of the short-spaced detector is measured in two energy ranges covering back-scattered gamma rays which have undergone relatively low and high attenuations respectively. A first density correction is determined from the difference between the apparent density derived from the count rate of the long-spaced detector and the density derived from the count rate of the short-spaced detector in the energy range covering gamma rays with relatively low attenuation. A second density correction is determined from the difference between the densities derived from the two short-spaced detectors' count rates. These two density corrections are added to the apparent density to give the true formation density.

Abstract: A cutting horizon sensing probe of a ranging drum shearer mining machine is mounted on a telescopic arm pivotally supported on the body of the machine such that when it is desired to move the probe into its operational position the arm is first extended from its non-operational position to an intermediate position and is then pivoted towards its operational position.

Abstract: In accordance with an illustrative embodiment of the present invention, an acoustic logging transducer array includes cylindrical transmitter and receiver transducers whose axes are aligned perpendicular to the longitudinal axis of a longitudinally extending support member in a borehole. The transducers are eccentered in the borehole with the receiving transducers mounted in a pad member which is supported near the borehole wall.

Abstract: A borehole investigating apparatus includes, an elongated support member, a first pair of wall-engaging pad members individually disposed on opposite sides of the support member along a given line and a second pair of wall-engaging pad members individually disposed on opposite sides of the support member along a given line at right angles to the given line for the first pair. The apparatus further includes first and second pad extending means for respectively moving the pad members of the first and second pairs away from the support member and against the borehole wall. The apparatus further includes primary driving means and a force dividing mechanism coupling this primary driving means to the first and second pad extending means for enabling unequal lateral extension of the pad members of the different pairs..Iaddend.