Abstract: Method for operating and testing a sensor assembly (210). The sensor assembly (210) preferably includes accelerometers with axes of sensitivity orthogonal to each other. The method preferably includes determining sensor tilt angle, determining the position of the sensor, and synchronizing the operation of the sensor.

Abstract: The present invention relates to a time-lapse or 4-D seismic data processing method in which cross-correlation of trace information in a series of time-lapse seismic images is used to distinguish one source of noise from another source of noise. After a source of noise has been identified, an appropriate filter is constructed to provide a correction to the noise produced by this particular source of noise. The data from one of the time-lapse seismic images is then applied to the filter to produce a corrected image. Differences between the corrected image and an uncorrected image are then used to determine time-lapse changes in the underlying geological structure. By being able to provide filters specifically tailored to correct each of the different types of noise present in a series of time-lapse seismic images, an accurate image of the time-lapse changes in the underlying geological structure is attained.