Seismic acquisition method and system

摘要

The maximum output of a seismic source array may be reduced by activating the individual seismic sources within these seismic source array in a pattern that is extended in time rather than by the presently employed conventional simultaneous activation of a large number of individual seismic sources. Methods are disclosed which take data shot with patterned sources and may use a sparse inversion method to create data with the about same image quality as that of conventional sources. In this manner the output of the maximum impulse of a seismic source array may be reduced by an amplitude factor of about 10 in the examples shown here, corresponding to a reduction of about 20 dB while maintaining virtually the same seismic image quality. The disclosed methods may be used in combination with any simultaneous sourcing technique. In addition, the disclosed methods may be used with a plurality of source arrays.

主权项

1. A method of seismic acquisition comprising:
(a) positioning a first seismic source array comprising a plurality of seismic sources over a seismic survey region, the seismic source array capable of generating an array output amplitude when all of said plurality of seismic sources are activated simultaneously; (b) choosing a plurality of different firing patterns, each of said plurality of firing patterns having a pattern output amplitude associated therewith, wherein said pattern output amplitude is a maximum amplitude of said seismic source array when said seismic source array is activated according to said associated firing pattern, and, wherein
(i) each of said plurality of different firing patterns is less than 10 seconds in length and greater than 0.5 seconds in length;(ii) each of said plurality of different firing patterns is chosen such that said associated pattern output amplitude is less than said array output amplitude; and,(iii) each of said firing patterns creates a plurality of notches in a frequency spectrum of any seismic data recorded therefrom; (c) activating the first seismic source array according to a selected one of a the plurality of different firing patterns; (d) performing step (c) at least two times for at least two different selected ones of the plurality of firing patterns; (e) recording a plurality of seismic signals reflected from one or more subterranean formations; and, (f) processing said plurality of seismic signals using a sparse inversion to produce processed seismic signals for use in seismic exploration, wherein said sparse inversion is obtained by solving
d≈A C m for m, where d is an acquired dataset from recording the plurality of seismic signals in (e), m is the processed seismic signals, C is an operator that ensures that m is spatially continuous, and A is a convolution operator chosen such that said notches correspond to a null space of A.