Activities in the oil industry are divided into three chronological sectors which are defined as:
Upstream:
The upstream sector basically covers all the stages involved in searching for, accessing and bringing the crude oil to the surface. It includes, for example, geological surveying, drilling and operating the wells.
Midstream:
This sector covers the processing, storing, marketing and transporting of the crude. Basically all the activities between production and refining.
Downstream:
This sector is where oil is finally refined and manufactured into products, sold and distributed to the consumers. Often midstream activities are combined into downstream as they overlap considerably.
