Upstream (petroleum industry)

The oil and gas industry is usually divided into three major sectors: upstream (also called exploration and production or E&P), midstream and downstream. The upstream sector includes searching for potential underground or underwater crude oil and natural gas fields, drilling exploratory wells, and subsequently operating the wells that recover and bring the crude oil or raw natural gas to the surface.

Source: Wikipedia — Upstream (petroleum industry) (CC BY-SA 4.0)