All the activities that involve exploring (Exploration and Production) i.e finding the oil. Such examples are drilling, seismic studies, casing, cementing, mud logging, measuring etc. All these activates are necessary to find oil below the seabed, analyse its quality and quantity and extract it from the ground.
In Nigeria, such activities are undertaken by the International Oil Companies(I.O.Cs) and Local Oil Companies (L.O.Cs).
Some of the IOCs include Shell Total, ExxonMobil, Agip, Chevron, LukOil, Addax Petroleum. The IOCs dominate the Upstream space as they control the largest production facilities and the most lucrative Oil blocs thereby producing the bulk of oil that the Federal Government sells.
Some of the LOCs include Seplat Petroleum, Amni Petroleum, Folawiyo Energy, NDEP Plc, Aiteo and Conoil Plc
These companies obtain OIL Prospecting Licenses (OPLs) from the Ministry of Petroleum to search for Oil and once it has been discovered in the right quantities, the OPL is converted to an Oil Mining License(OML). An OML permits the company to start drilling, extraction, storage and sales of the crude oil extracted from the ground.