Atlantic Richfield Company

Mahlon G Justice, Jr

Tom P Airhart

A method of seismic exploration is disclosed wherein a signal recording obtained from subsurface geophone receivers placed below the weathered layer is used to characterize the waveform of the downgoing signal generated in the earth by a surface seismic source. The reflections of the source signal measured at the earth's surface at a point remote from this source are then deconvolved with an operator derived from the subsurface waveform in order to eliminate or compensate for the filtering effect of the weathered layer. Successive measurements of the downgoing source signal are taken at the earth's surface as the source is advanced along a seismic line. One of such surface signals can be combined with the subsurface signal recording in order to derive a transfer function indicative of such filtering effect for the intervening weathered layer. This transfer function may then be convolved with each of the successive surface signals to predict corresponding updated values for the subsurface waveform (and hence the deconvolution operator) as the source is moved from each shot point to the next.

Method for seismic exploration including compensation for near surface

An apparatus and method for maximizing the shear wave energy imparted into the soil upon the impacting of a base plate by an impact mass from a seismic generator. A seismic generator is disposed at an angle relative to a line generally perpendicular to the surface to the ground. The angle varies with soil conditions and the angle is determined by locating an accelerometer on the base plate of the generator and observing the horizontal acceleration rate as indicated by the accelerometer. If the acceleration rate exceeds a predetermined value, the anguular disposition of the generator s changed to decrease the angle either manually or automatically until the acceleration rate no longer exceeds a predetermined value.

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Plano, TX, United States of America

Mahlon G Justice, Jr