US 12,072,461 B2
Modified simultaneous long-offset acquisition with improved low frequency performance for full wavefield inversion
Stig Rune Lennart Tenghamn, Houston, TX (US)
Assigned to PGS Geophysical AS, Oslo (NO)
Filed by PGS Geophysical AS, Oslo (NO)
Filed on May 22, 2020, as Appl. No. 16/881,992.
Claims priority of provisional application 62/926,958, filed on Oct. 28, 2019.
Prior Publication US 2021/0124073 A1, Apr. 29, 2021
Int. Cl. G01V 1/38 (2006.01)
CPC G01V 1/3808 (2013.01) [G01V 1/3843 (2013.01); G01V 2210/165 (2013.01)] 32 Claims
OG exemplary drawing
 
1. A method of marine surveying, comprising:
towing a first source with a source vessel;
towing a second source with a survey vessel such that an inline separation of at least 5 km exists between the source vessel and the survey vessel;
towing a streamer spread comprising standard-offset streamers at a first depth with the survey vessel such that a lead end of each of the standard-offset streamers is coupled to a spreader line; and
towing at least two long-offset streamers at a second depth with the survey vessel, wherein:
the first depth is 10 m to 30 m;
the second depth is greater than 30 m;
the second source is disposed proximate to a centerline of the streamer spread such that the streamer spread comprises a port side plurality of standard-offset streamers port of the second source and a starboard side plurality of standard-offset streamers starboard of the second source;
the standard-offset streamers in the port side plurality have a constant standard-offset streamer crossline separation between them at the spreader line;
the standard-offset streamers in the starboard side plurality also have the constant standard-offset streamer crossline separation between them at the spreader line;
a first one of the long-offset streamers is disposed proximal to one of the standard-offset streamers in the port side plurality at a first crossline separation therefrom;
a second one of the long-offset streamers is disposed proximal to one of the standard-offset streamers in the starboard side plurality at a second crossline separation therefrom; and
the first crossline separation and the second crossline separation are both smaller than the standard-offset streamer crossline separation.