Upstream companies are involved in the initial stages of the oil and gas industry, focusing on the exploration and production of crude oil and natural gas. These companies search for potential underground or underwater oil and gas reserves, using various technologies and methods to locate and assess these resources. Once reserves are identified, they drill wells to extract the hydrocarbons. The upstream sector is crucial for supplying raw materials to downstream companies, which refine and distribute the products. Major players in this sector include multinational corporations like ExxonMobil, Chevron, and BP, which operate in various regions around the world to secure energy resources.