US 11,994,640 B2
Attenuation of low-frequency noise in continuously recorded wavefields
Stian Hegna, Hovik (NO); and Tilman Klüver, Sande (NO)
Assigned to PGS Geophyscial AS, Oslo (NO)
Filed by PGS Geophyscial AS, Oslo (NO)
Filed on Mar. 30, 2020, as Appl. No. 16/835,015.
Claims priority of provisional application 62/835,018, filed on Apr. 17, 2019.
Prior Publication US 2020/0333490 A1, Oct. 22, 2020
Int. Cl. G01V 1/34 (2006.01); G01V 1/36 (2006.01)
CPC G01V 1/345 (2013.01) [G01V 1/364 (2013.01); G01V 2210/56 (2013.01)] 21 Claims
OG exemplary drawing
 
1. In a process for generating an image of a subterranean formation based on pressure data that were continuously recorded during a geophysical survey, the improvement comprising:
computing upgoing pressure wavefield data at stationary-receiver locations based on continuously recorded pressure data and vertical velocity data;
computing a total source wavefield based on source wavefields emitted from individual airguns of a source;
attenuating low-frequency noise in the upgoing pressure wavefield based on the total source wavefield to obtain low-frequency noise attenuated upgoing pressure wavefield data at stationary-receiver locations; and
generating an image of the subterranean formation, or data indicative thereof, based at least in part on the low-frequency noise attenuated upgoing pressure wavefield data at stationary-receiver locations, thereby reducing low-frequency noise artifacts in the image.