"Upstream" and "downstream" are general business terms referring to an oil or gas company's location in the supply chain. The closer to the end user a function or firm is, the further downstream it is said to be. Raw material extraction or production are elements of the supply chain considered to be upstream. The upstream companies identify oil and natural gas deposits and engage in the extraction of these resources from underground. These firms are often called exploration and production companies. Refiners represent the downstream element of the oil and gas supply chain.
Upstream oil and gas operations identify deposits, drill wells, and recover raw materials from underground. This sector also includes related services, such as rig operations, feasibility studies, machinery rental and extraction chemical supply. China National Offshore Oil Corporation and Schlumberger are examples of large companies that focus on upstream services. Many of the largest upstream operators are the major diversified oil and gas firms, such as Exxon-Mobil.
Midstream operations link the upstream and downstream entities. Midstream operations mostly include resource transportation and storage, such as pipelines and gathering systems. Kinder Morgan and Williams Companies are two examples of midstream firms.
Downstream operations include refineries and marketing. These services turn crude oil into usable products such as gasoline, fuel oils, and petroleum-based products. Marketing services help move the finished products from energy companies to retailers or end users. Marathon Petroleum and Phillips 66 are two noteworthy examples of downstream companies.