Geophone calibration technique

Abstract

Various techniques are described which may be used to facilitate and improve seismic exploration activities. For example, one aspect of the present invention is directed to a technique for enabling in-situ measurement of geophone response parameters. Another aspect of the present invention is directed to a technique for improving geophone calibration and for improving the accuracy of measurement of geophone response parameters. Yet another aspect of the present invention is directed to a technique for compensating geophone response output data in order to improve the accuracy of such data.

Description

[0001] This is a division of U.S. patent application Ser. No. 10 / 928,953, filed Aug. 27, 2004.FIELD [0002] The present invention relates to geophones, devices for sensing vibrations in earth formations. The invention may be applicable to other types of vibration transducers, either in sensing or transmitting operation. BACKGROUND [0003] In seismic exploration, the vibrations in the earth resulting from a source of seismic energy are sensed at discrete locations by sensors and the output of the sensors used to determine the nature of the underground formations. The source of seismic energy can be natural, such as earthquakes and other tectonic activity, subsidence, volcanic activity or the like, or man-made such as acoustic noise from surface or underground operations, or from deliberate operation of seismic sources at the surface or underground. Sensors fall into two main categories; hydrophones which sense the pressure field resulting from a seismic source, or geophones which sense...

AI Technical Summary

Benefits of technology

[0009] Yet another aspect of the present invention is directed to a technique for processing seismic exploration information generated from seismic exploration activities. A first portion of the seismic information includes geophone response output information generated by at least one geophone. A second portion of the seismic exploration information includes source signal information relating to at least one source signal used in performing the seismic exploration activities. A first portion of response parameter values associated with a first geophone is determined. In one embodiment, the first portion of response parameter values may be determined by performing at least one calibration test procedure on the geophone. Accuracy of the seismic exploration information may then be improved by modifying at least a portion of the seismic exploration information to compensate for one or more of the first portion of response parameter values.

Problems solved by technology

Typically, geophone manufacturers and vendors do not perform any calibrations on their geophone units before the units are sold to customers.

However, such tolerance guarantees are not a substitute for proper calibration of the geophone units.

However, conventional geophone calibration tests are often inadequate for assuring the desired precision of the geophone measurements typically demanded for many of today's seismic exploration activities.

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