MODIFIED SIMULTANEOUS LONG-OFFSET ACQUISITION WITH IMPROVED LOW FREQUENCY PERFORMANCE FOR FULL WAVEFIELD INVERSION

摘要

A method and apparatus includes: towing a first source with a source vessel; towing a second source with a survey vessel, the survey vessel following the source vessel by at least 5 km; towing a streamer spread at a first depth with the survey vessel; and towing a pair of long-offset streamers at a second depth and following the source vessel by at least 5 km, wherein: the first depth is 10 m to 30 m, and the second depth is greater than 30 m. A method and apparatus includes: towing a first source with a source vessel; towing a second source with a survey vessel, the first source and the second source being separated by at least 5 km; towing a streamer spread at a first depth with the survey vessel; towing a pair of long-offset streamers at a second depth, wherein: the first depth is between 10 m and 30 m, and the second depth is greater than 30 m; acquiring long-offset data with long-offset sensors distributed along the long-offset streamers; and constructing a velocity model with the long-offset data. A method and apparatus includes: towing a first plurality of streamers at a first depth of 10 m to 30 m; receiving first signals generated by a first source with the first plurality of streamers; towing a second plurality of streamers at a second depth of greater than 30 m; while receiving the first signals, receiving second signals generated by a second source with the second plurality of streamers; wherein: the first source and the second source are separated by at least 5 km, the second signals represent long-offset data, and a forward-most receiver on each of the second plurality of streamers has a same inline offset from the first source as a forward-most receiver on each of the first plurality of streamers.