Abstract: Apparatus for testing a logging sonde having a surface including elements which are electrically insulated the one from the other comprises an enclosure within which the sonde may be positioned. Conductive fluid under pressure is introduced into the enclosure so as to establish electrical conduction paths between different, spaced apart points on the surface of the sonde. Electrical communication between respective ones of the elements and the exterior of the enclosure is effected so that the sonde may be tested such as by deriving through operation of the sonde a measurement of the known resistivity of the enclosure wall.

Abstract: Method and apparatus, for use in the detection of inelastic neutron scattering gamma ray spectroscopy, effect data acquisition efficiency enhancement by operating a neutron generator such that a resulting output burst of fast neutrons is maintained for as long as practicably possible until a gamma ray is detected. Upon the detection of a gamma ray the generator burst output is terminated. Pulsing of the generator may be accomplished either by controlling the burst period relative to the burst interval to achieve a constant duty cycle for the operation of the generator or by maintaining the burst period constant and controlling the burst interval such that the resulting mean burst interval corresponds to a burst time interval which reduces contributions to the detected radiation of radiation occasioned by other than the fast neutrons.

Abstract: The determination of a "composite" parameter of the formation water in formations surrounding a borehole, for example the composite conductivity of the formation water, is used in the disclosure to obtain a relatively accurate determination of formation characteristics, such as water saturation. The determined values are meaningful even in shaly regions of the formations. In contrast to past approaches which attempted to determine the volume and distribution type of shale or clay present in the formations and then introduce appropriate factors which often involve substantial guesswork, the disclosed technique determines a composite water parameter, for example a composite water conductivity, which represents the conductivity of the bulk water in the formations, including both free water and bound water. Bound water trapped in shales is accounted for in this determination so unlike prior techniques, the shales can be considered as having a porosity.

Abstract: The composition of an earth formation is investigated by repetitively irradiating the formation with bursts of fast neutrons and generating an inelastic energy spectrum from gamma ray counts detected during first time intervals which are contemporaneous with the bursts. A second energy spectrum is generated from gamma ray counts detected during second time intervals which immediately follow respective first time intervals. Gamma ray counts comprising the second spectrum are thereafter subtracted from the gamma ray counts comprising the inelastic spectrum to provide an inelastic energy spectrum with reduced background.

Abstract: At least four waveforms representative of sonic waves obtained from an acoustic investigation of a borehole with at least four sonic receivers are combined to automatically measure a parameter of a wave present in the waveforms. The waveforms are derived from sonic receivers which are selectively spaced from each other as well as the sonic transmitter whose sonic pulses caused the sonic waves. Several techniques are described to measure acoustic wave parameters such as the interval travel time of compressional and shear waves for open or cased boreholes. In accordance with one technique a multiple fold correlation process and apparatus are described to measure the acoustic wave parameter.

Abstract: A method and apparatus are described for detecting an acoustic wave in a waveform produced from a sonic receiver in response to an acoustic investigation of a borehole. The maximum amplitude of the waveform is measured and a portion thereof utilized as a threshold for comparison with successively different combinations of initial portions of the waveform and the waveform location, where the threshold is exceeded, is identified as the location of the wave. A pattern comparison is made between waveform segments where the acoustic wave is initially located to provide a correction factor for a more accurate locating of the acoustic wave. A parameter of the wave, such as its interval travel time is measured with the acoustic wave locating techniques.

Abstract: A predetermined signal is removed from waveforms generated in an acoustic investigation of a borehole to enable the accurate detection of relatively weak formation signals. A plurality of waveforms are produced from different sonic receivers used in an acoustic investigation of an earth formation from inside casing set in a borehole. The waveforms include a casing signal which is representative of the acoustic casing wave which traveled from a transmitter through the casing to the receivers. The casing signal is removed by aligning the waveforms in accordance with the known travel times for the casing wave from the transmitter to the receivers and summing the waveforms to produce a casing signal emphasized waveform. A portion of the latter is then subtracted from the waveforms from which the casing signal is thus effectively filtered to facilitate detection and analysis of formation signals present in the waveforms.

Abstract: A depth measurement system produces independent signals, each presumably corresponding to the same movement of a wireline if produced under ideal wireline measurement conditions. The system utilizes the signals to provide an accurate and repeatable signal under varying wireline measurement conditions and is particularly suitable for driving a recorder for depth recording and merging measurements from tools lowered in the borehole on different runs and to detect slippage between the wireline and a tangential wheel used to provide one of the signals. Slidably mounted measurement wheels insure tangential engagement of opposite sides of the wireline with equal pressure. Low-load signal generators each responsive to the rotation of the opposing wheels provide independent signals, each ideally corresponding to the movement of the wirline engaged between them. Magnetic marks written on the wireline are sensed and provide yet another independent signal.

Abstract: An automatic wiping apparatus, provided for a disc record player, comprises a pad supported on a free end of an elongated leaf spring. The other end of the leaf spring is angularly secured to a housing support attached to the underside of a lid of the player, such that when the lid is closed the pad will be urged into contact with the surface of a disc supported on a turntable provided in the player. A rigid frame is pivotally mounted to the housing support, and is provided with a first member for supporting the free end of the leaf spring in a raised state, precluding contact between the pad and the disc surface, in response to the string force of a tongue spring acting on a second member of the rigid frame.

Abstract: A disc record caddy comprises a pair of substantially flat circular covers releasably held in channels defined along the inside rim of an expandable circular ring. Spring elements bias the ring into a contracted shape to radially restrain a disc retained between the pair of covers. A platform, mounted on a base of a disc record player system, horizontally supports the caddy in an elevated position over a turntable of the system and includes means for expanding the ring to release the covers. A turntable spindle incorporates a lowering/lifting mechanism which lowers the cover nearest the turntable and the disc supported thereon onto the turntable for record playback purposes, the other cover being retained at the platform level by the radially inward extension of the land defined between the ring channels.

Abstract: In a still frame playback mode, a video disc player reproduces a carrier signal which is frequency modulated in accordance with a composite video signal representative of successive repetitions of two interlaced image fields constituting a single image frame and comprising a luminance signal component, a chrominance signal component and synchronizing information, including a color burst. An FM demodulator develops a composite video signal, which is characterized by a 180.degree. phase discontinuity in the chrominance signal component between the frame end and the succeeding frame start. A first inverter circuit inverts the phase of the color burst every other image frame piror to the processing of the composite video signal output in time base correction and drop-out compensation circuits.

Abstract: High speed writing apparatus, for mapping 1:1 polar plots of disc record defect locations on disc-shaped electrosensitive paper, accepts electrical signals representing defect occurrences from a defect detector which scans the disc record surface in a spiral scanning pattern. These signals activate a high voltage switch circuit that produces an electric current between an electric writing pen stylus and a conducting surface of a turntable of the printing apparatus upon which the disc shaped electrosensitive paper is mounted. Relative motion is established between the turntable and the writing pen in a manner causing markings resulting from pen activations to be located on the electrosensitive paper with radial and circumferential positions corresponding to the locations of the defects appearing on the disc record, thereby generating 1:1 polar plots of the defect locations on the paper.

Abstract: Defect detection apparatus, for optically inspecting a spiral groove of a video disc record, directs a coherent light beam at the grooved surface of the disc. The incident beam, focused at a point beyond the disc surface, illuminates the grooved surface with a light spot that spans a plurality of convolutions of the groove. Relative motion is established between the disc surface and the incident beam in a manner causing the illuminating spot to rapidly scan the groove surfaces in a coarse spiral pattern. The structure of the illuminated groove convolutions, absent any defects, serves as a diffraction grating for diffracting the light into an undeviated zero diffraction order cone of light that converges at a first location in a plane spaced from the disc surface and into deviated higher diffraction order cones of light that converge at additional locations in said plane separated from the first location.