It would be quicker and cheaper to use chartered oil survey vessels, they exist in quantity, their operating costs are well known and they have the needed skills.
Not in quantity - I'm not aware of any that are equpped to do sonar surveys at these kind of depths, although there might be a few in the Gulf of Mexico, Brazil and West Africa, using either deep-tow vehicles or AUVs.
The majority of the world's "oil survey vessels" are seismic vessels, which are completely unsuited for this kind of work.