Mobil Oil Corporation

Wayne A Penner

Robert D Peterson

Charles D Ray

Carl A Quaglino

Thomas W Cook

James W Goode

Lyndell F Scott

Gary P Baggett

Robert G Nelson

A cathode ray tube is used for quality control in conjunction with a method and apparatus for monitoring seismic data gathers. As seismic reflection data is acquired, it is displayed on a cathode ray tube and visually monitored to determine whether information channels are to be deleted due to excess noise, improper amplification, etc., prior to recording the acquired data.

Monitor display control

A floating point formatter for changing fixed point serial digital data, such as that received by a seismic data acquisiton system, is disclosed wherein fixed point serial digital data is received and scaled to remove any bias added by preamplification. The scaled data is shifted a predetermined number of bits and a resulting exponent is calculated. The shifted data signal and corresponding exponent are combined and further scaled to permit stacking the data without exceeding the system capacity.

Serial floating point formatter

An electronic circuit is disclosed wherein a two-stage DC offset filter is provided and implemented serially to coincide with serially implemented seismic data gathers. A first stage corrects the offset in a multichannel system due to amplification stages common to all channels. A second stage includes a circuit for determining the DC offset unique to each channel and compensates for each channel automatically and individually.

DC offset filter

A seismic data generation and collection system is described for use in a exploration vessel for determining the subsea structure of the earth. A plurality of acoustic energy sources are towed behind the boat and acoustic waves are emitted therefrom by conventional means. The reflection at the subsea interfaces of the acoustic waves are picked up by the energy detectors which produce analog signals. These analog signals are then converted to digital data; multiple computers are used to reformat the data into a desired format. A real time monitor computer and monitor plotter may also be provided to assist the operator in evaluation of the operation of the system. The desired record format includes header information relating to the parameters under which the seismic shot was made, which may be written directly onto the magnetic tape containing the seismic data.

Seismic exploration system

A seismic recording system employs amplifiers, a multiplexer, and an analog-to-digital converter for converting analog seismic reflection signals obtained during seismic exploration operations to a serial output of multiplexed digital samples. An input controller restores to the digital samples the original amplitude of the seismic signals as they were received by the field recorder and scales the digital samples for later compositing into a seismic record in a central processing unit. An output controller then applies to each digital sample in the composite record a desired gain prior to recording on a magnetic tape unit.

System for recording and processing seismic reflection signals

A seismic exploration system employs a seismic energy source, a plurality of seismic energy detectors, and a seismic recording system. The recording system employs amplifiers, a multiplexer, and an analog-to-digital converter for converting analog seismic reflection signals resulting from repetitive firings of the seismic energy source to a serial output of multiplexed digital samples. These digital samples are sequentially strobed into selected storage locations in core memory, such storage locations being selected such that the multiplexed samples are reoriented serially by channel in successive ones of the storage locations. The digital samples are next sequentially strobed out of core memory by such successive storage locations to produce prior to each firing of the seismic source a serial-by-trace record of the detected seismic reflection signals resulting from the previous firing of the seismic source.

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Farmers Branch, TX, United States of America

Wayne A Penner