Targeted activation parameters for marine seismic sources

摘要

Performing a marine geophysical survey over a survey area, comprising: towing 710 a first vibratory signal source; identifying 720 a portion of the survey area; driving 730 the first vibratory source using a first digital code having a first length when targeting an identified portion of the survey area; and driving 740 the first vibratory source using a second digital code having a second length that is different than the first length when targeting another portion of the area. In another aspect the identifying is based on signals emitted from the first vibratory signal source, reflected from the portion and measured by a plurality of seismic sensors, wherein identifying is performed based on stacking survey traces and detecting a change in amplitude that meets a threshold. Another aspect further includes driving at least a portion of a set of signal sources using a first value of an output parameter when targeting the identified portion, and driving at least a portion of the set of sources using a second value of the output parameter when targeting the other portion. The output parameter may specify length of digital code, sweep duration, or frequency content among other things.