Oil and natural gas are major industries in the energy market and play an influential role in the global economy as the world's primary fuel sources. The processes and systems involved in producing and distributing oil and gas are highly complex, capital-intensive, and require state-of-the-art technology.
Historically, natural gas has been linked to oil, mainly because of the production process or upstream side of the business. For much of the history of the industry, natural gas was viewed as a nuisance and even today is flared in large quantities in some parts of the world, including the United States.
Natural gas has taken on a more prominent role in the world's energy supply as a consequence of shale gas development in the United States, as mentioned above, and its lower greenhouse gas emissions when combusted when compared to oil and coal.