Marc, I am in the industry and , I am not sure of your question, there are large vendors which supply services to the major and minor oil companys.
Noble, and Graywolf drilling are an example of rig contractors.
Baker Hugh and Schlumberger offer formation evalulation, cemmenting, and completion operations.
All the companies us inhouse earth scientists to guess where to drill at.
using 3D seismic as a main exploration tool
3D, involes both acqusition, and interpetation companys like Paragon, landmark, Western, Corelabs.
I am currently buying all the Hk I can. They are really on top of their game right now with outstanding longterm assets, with thousands of newly acquired leases holding drill sites to their recent press releases.