Abstract: An elongated borehole logging tool employs an acoustic energy transducer for directing acoustic energy pulses toward a borehole wall at a repetition rate synchronized with rotational speed of the tool within the borehole.

Abstract: A linear digital frequency sweep synthesizer employs an up-down counter for producing a first signal having a plurality of pulses with time interval between pulses linearly increasing with time and a phase lock loop for producing a second signal having a plurality of pulses having a frequency sweep linearized to the linearly increasing time intervals of such first signal.

Abstract: An acoustic borehole logging tool employs at least one transducer for directionally transmitting and receiving bursts of acoustic energy into the formations surrounding a borehole. The transducer is mounted in a compartment within the tool which is filled with a coupling liquid. A window in the periphery of the compartment consists of a material having a thickness which maximizes the signal-to-noise ratio of the acoustic energy for the particular wavelength of acoustic energy being transmitted.

Abstract: The data transmission rate in a cable telemetry system is improved by preconditioning an encoded data signal prior to discriminating and decoding it with a filter/amplifier employing an operational amplifier having a non-inverting input connected to receive the data signal, an inverting input which is grounded through a series connected resistance and capacitance and an output which is feedback connected to said inverting input by a resistance.

Abstract: A motor speed detector employs a magnetic sensor for detecting rotational movement of rotor armature segments of the motor and for producing real tachometer pulses in response to such movement. False tachometer pulses produced by extraneous non-rotor motor components are discriminated against to produce a signal representative of actual motor rotational speed.

Abstract: A borehole logging tool employs an energy transmitter and receiver for scanning a borehole with energy pulses. An orientation pulse is produced each time the tool rotates past a predetermined orientation position. The time period between orientation pulses is measured and divided into a plurality of discrete intervals. Sine and cosine functions are generated for the measured time period having a sine and cosine value corresponding to each of the discrete intervals. The sine and cosine functions are used to produce sweep functions for controlling the outward sweep of the electron beam of a PPI display device so as to produce a circular rotating pattern in which each revolution corresponds in time to a measured time between orientation pulses. The output of the receiver modulates the electron beam sweep to generate a visual display of the azimuthal scan of the borehole.

Abstract: A logging tool recording system counts and converts depth pulses into a digital coded format. Such digital coded format is converted to a serial digital word for recording on an analog recorder. During playback the digital serial word is converted back into a digital coded format for reproduction by means of a visual digital display.

Abstract: A pulsed neutron system including an accelerator tube having a target, an ionization section, and a replenisher section for supplying accelerator gas. An ionization circuit includes means for applying repetitive ionization pulses to the ionization section. The current in the ionization circuit is monitored in order to detect incremental current events occurring during the ionization pulses. A count rate function is produced which is representative of the frequency of the incremental current events. The power supplied to the replenisher section is controlled in response to the count rate function. The replenisher power is increased in response to a decrease in the count rate function and decreased in response to an increase in the count rate function.

Abstract: A radar transmitter directs a beam of microwve energy at a first frequency through the atmosphere. A gas seep in the atmosphere irradiated by the beam of microwave energy is excited to emit microwave energy at a second frequency characteristic of the particular species of gas. A radar receiver is tuned to produce video signals representative of the microwave energy at the second frequency. An amplitude discriminator measures the amplitudes of the video signals during each radar sweep as an indication of gas concentration in the seeps and counts the number of video signals during each radar seep as an indication of the size of the seeps.

Abstract: A pulsed neutron system includes an accelerator tube having a target, an ionization section, and a replenisher for supplying accelerator gas. The power supplied to the replenisher is controlled to maintain the ionization pulse time duration within the upper and lower limits of a time window. A comparator compares the ionization pulse time duration to the upper and lower limits of the time window and produces an output pulse which is utilized by an operational amplifier to operate a stepping motor in one direction if the ionization pulse time duration exceeds the upper limit of the time window and in a reverse direction if the ionization pulse time duration is below the lower limit of the time window. The stepping motor positions a variable autotransformer which increments the voltage applied to the replenisher to change the ionization pulse time duration if it does not fall within the upper and lower limits of the time window.

Abstract: An acoustic velocity logging tool employs a transmitter and a pair of receivers. Acoustic pulses from the transmitter pass through the formation surrounding the borehole to the receivers. The received signals, along with control signals, are transferred to an uphole recording system. A record unit operates to apply these receiver and control signals to a magnetic tape recorder. A playback unit transfers the recorded receiver signals to the intensity modulation input of a cathode-ray oscilloscope and, in response to the recorded control signals, applies a trigger pulse to the sweep input of the cathode-ray oscilloscope. A film recorder makes a continuous film recording of the receiver signals as they appear as variable-density traces on the face of the cathode-ray oscilloscope.

Abstract: A borehole logging system employs a gamma-ray detector for measuring the natural gamma radiation of the earth formations surrounding a borehole. Three energy band selectors, each employing a discriminator and count rate meter, separate the output of the gamma-ray detector into potassium, uranium, and thorium energy band signals. A first operational amplifier determines the difference between the potassium energy band signal and those portions of the uranium and thorium energy band signals which represent the influence of uranium and thorium gamma radiation within the potassium energy band, this difference representing the correct potassium gamma radiation. A second operational amplifier determines the difference between the uranium energy band signal and that portion of the thorium energy band signal which represents the influence of the thorium gamma radiation within the uranium energy band, this difference representing the correct uranium gamma radiation.