Seismic amplifier means and method
AssigneeTexaco Inc.
InventorsHerbert J. Meyer, Donald L. Howlett
Life of this patent
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Abstract
The seismic amplifier includes an amplifying circuit which amplifies an analog signal to provide an amplified analog signal. The amplified analog signal is converted to digital signals. A controlled network connected to the amplifier circuit controls the gain of the amplifier circuit in a manner so that the gain for a current seismic operation, except for an initial seismic operation, is determined during the next previous vibration seismic operation.
Claims12
A seismic amplifier for use with a vibration type seismic system having geophones and providing a shot point pulse at the end of each shot point comprising:
- means for amplifying an analog seismic signal from the geophones to provide an amplified analog signal;
- converter means connected to the amplifier means for converting the amplified analog signal to digital signals;
- receiver means for receiving shot point pulses from the seismic system;
- and
- control means connected to the receiver means, to the amplifier means and to the converter means for controlling the gain of the amplifier means in accordance with at least one of the digital signals and a received shot point pulse in a manner so that the gain for a current shot point was determined during the next previous shot point;
- wherein the control means include:
- counter means connected to the receiver means for being reset by a received shot point pulse from the receiver means and for counting pulses, and providing a first enabling signal when its count is less than a predetermined range of counts, providing no enabling signal when its count is within the predetermined range of counts, and providing a second enabling signal when its count is greater than the predetermined range of counts,
- pulse means connected to the counter means and to the converter means for providing pulses to the counter means during a shot point each time the output from the converter means is over half of the converter means full scale and for providing pulses to the converter means to control the converting of the analog signal to to digital signals, and
- control signal means connected to the receiver means, to the amplifier means and to the counter means in accordance with an enabling signal or the absence of an enabling signal and the shot point pulse from the receiver system so as to control the gain of the amplifier means.
A method of amplifying an analog seismic signal derived from use of a vibration type seismic system having geophones and which provides a shot point pulse at the end of each shot point comprising the steps of:
- amplifying the analog seismic signal from the geophones with an amplifier means to provide an amplified analog signal,
- converting the amplified analog signal to digital signals with an analog-to-digital converter,
- receiving shot point pulses from the seismic system,
- controlling the gain of the amplifier means in accordance with at least one of the digital signals and a received shot point pulse in a manner so that the gain for current shot point was determined during the next previous shot point, in which the control step includes:
- providing the pulses to a counter during a shot point each time the digital signals from the converter means represents a value over half of the converter's full scale value, to the receiver means,
- counting the provided pulses with the counter,
- providing a first enabling signal when the count in the counter is less than a predetermined range of counts,
- providing a second enabling signal when the count in the counter is greater than the predetermined range of counts,
- providing control signals to the amplifier means in accordance with an enabling signal or the absence of an enabling signal and the shot point pulse so as to control the gain of the amplifier means.
Dependencies are inferred from the claim text.