JLT ran the seismic jobs, is an HSE specialist, speaks fluent Spanish, and knows Argentina (and other bits of LatAm, or everywhere for that matter), and will know who provided the aircraft, and have a view on the alternatives, and suitable local specialist advisers, etc. (I haven't met him since then so have no interest in passing the contact except to assist).
Apologies for picking the wrong bit of Shell.
We were working in the 500-1500m altitude zone just as it kicks up towards the major peaks. The hydrocarbon reservoirs tend to be in that zone. If you are into mineral mining they can be much higher up.
If you are stuck then drop me a line and I'll enquire through my links in Salta/Jujuy etc.
ds/pp