Overview
A company man in the petroleum industry refers to a representative of an operating/exploration company. Other terms that may be used are company representative, foreman, drill site supervisor (DSV), company consultant, rigsite leader or "well site manager".
In a normal scenario, gas/oil-drilling (exploration) companies rent or lease the rigs from another company that owns the rig, the drilling contractor. The majority of the personnel on the drilling rig, called 'the rig crew', are employees of the drilling contractor. The company man is the on-site representative of the operating/exploration company and is in overall charge of the drilling and associated activities. Rig operations and maintenance and crew upkeep are attended to by the toolpusher, who works for the drilling contractor.
Expertise
A company man is not a supervisor in the traditional sense. He/she is representing the oil company that is paying for the well amongst other companies performing the services. In matters where safety may be questioned, the oil rig workers, who probably aren't employed by the same company as the company man, may refuse to perform an action requested by the company man. In recent years it has become standard safety policy that anyone can "Stop the Job" if they feel there is a hazard that has not been properly addressed. This can be found in most contractor safety manuals and is generally encouraged by the drilling company also.
The company man is knowledgeable in the area of drilling operations and to some extent completion operations. He/she is not generally responsible for defining the technical aspects of the well, but instead works with a team of office-based engineers and geologists and is the team member responsible for carrying out the written drilling program in an efficient and safe fashion. Since most of the physical work is carried out by contractors that may have separate interests from the oil company, the company man is often the sole representative of the oil company on location to ensure that plans are carried out according to specifications, time-lines and budgets. The company man usually gives orders only to the supervisor(s) of the drilling contractor and various service companies, lest he/she run the risk of violating the "Independent Contractor" concept and possibly incurring additional liability (e.g., for personnel injuries) for his/her own company.
From Wikipedia (CC BY-SA 4.0).