Upstream and downstream are business terms that refer to a company’s location in the supply chain. The closer to the end user a function or firm is, the further downstream it is. The oil and gas supply chain often uses upstream and downstream references.Upstream companies discover oil and natural gas deposits, and drill wells to extract them. Rig operations, feasibility studies, machinery rental and extraction chemical suppliers are also part of the upstream sector. Many of the largest upstream operators are the major diversified oil and gas firms. Exxon-Mobil is an example. Downstream operations include refineries and marketing. They turn crude oil into usable products, such as gasoline. Marketing services move the finished products to retailers or end users. Marathon Petroleum and Phillips 66 are examples. Midstream operations link the upstream and downstream entities. They’re mostly transportation and storage services for resources, such as pipelines and gathering systems. Examples include Kinder Morgan and Williams Companies.