Upstream, Midstream & Downstream
The upstream segment of the industry, often called exploration & production, is traditionally what comes to mind when people think of the oil and gas industry. Companies will search prospective areas for potential reserves of oil and gas and perform geological tests called seismic tests, to determine the size and composition of the resource. Initial wells areoften drilled to "explore" the basin, and if satisfied with results, a companywill enter the production phase to extract the hydrocarbons.
Often coupled with the downstream segment, the midstream sector involves the transportation, storage and marketing of various oil andgas products. Depending on the commodity and distance covered, transportationoptions can vary from small connector pipelines to massive cargo ships making trans-ocean crossings. While most oil can be transported in its current state, natural gas must be either compressed or liquefied for transport. The midstream sector also includes the storage of oil and natural gas, which balances the fluctuations between supply and demand and helps ensure a secure supply of energy products.
The downstream sector involves the refining and processing of hydrocarbons into usable products such as gasoline, jet fuel and diesel. Refining is required since "raw" hydrocarbons extracted from the ground are rarely useful in their natural form. The refining process is a complex chemical process that helps separate the hundreds of hydrocarbon molecules into useful forms. Petrochemical plants also break down hydrocarbons into chemical compounds that are used to create a myriad of products ranging from plastics to pharmaceuticals.
Services and Consulting
Although not officially a sector of the industry, this"sub-sector" is an increasingly important part of the oil and gas industry and assists the effectiveness and efficiency of all three major streams. The service sector includes companies that assist with the repairs, maintenance, troubleshooting, construction and operation of projects in all areas of the industry. It is common practice in the industry for firms to employ several service companies to execute specific components of projects, including drilling, water filtration, engineering design, and environmental management. Consultants arealso employed in all areas of project design and implementation, and can helpwith project economics, staffing, financing, risk management, geological assessment and community outreach, for example.