Image of an oil extraction site in Williston

Oil and natural gas are often lumped together. This is intuitive since it’s called the “oil and gas” industry. But oil and natural gas are different in many ways, including the way they are formed. Northern Oilfield Services in Williston specializes in oilfield equipment rentals, including drilling equipment, wellheads, valves, and frac iron. Below, we’ll take a brief look at the formation of oil and natural gas. Contact us today to get started!


Both oil and natural gas are formed deep in the earth. They are fossil fuels, so named because it takes a lot of time to form fossil fuels — millions of years, in fact. However, fossil fuels are not made out of fossils. The fossil part of the name refers to the fact fossil fuels are ancient, which is true.

Petroleum (which is oil and natural gas) are indeed made up of dead animals, mostly small organisms called plankton that float around in the ocean today in the billions and are eaten still by many animals. When these microscopic organisms died, their remains sank to the bottom of the ocean. Living creatures absorb energy from the sun, which is stored as carbon molecules in their bodies. As more and more plankton and other animals died and debris covered them up, they were eaten by bacteria. This and other processes produce chemical reactions that will eventually form something called kerogen and bitumen, which is a black tar substance and a petroleum ingredient.

This kerogen then must undergo more processes, including pressure from more debris and intense heat in order to become what we know as crude oil. Kerogen will eventually transform into hydrocarbons (hydrogen and carbon) that is petroleum or crude oil.


Both oil and natural gas go through this exact process. However, natural gas requires even more heat. When this happens, the hydrocarbons that form oil and natural gas become even smaller. These hydrocarbons are less dense than the rock surrounding them, so they begin to rise in the earth. Eventually, they get trapped by some land formation in the earth. They then build up, forming a reservoir, where they will stay forever until they are drilled.

Beyond this, crude oil is made up of very complex hydrocarbons can determine its viscosity and volatility. Crude oil is made different as well by the organisms that it is made up of. This requires refining in order to be used.

Natural gas is made up mostly of hydrocarbons in the gas form: ethane, propane, butane, and pentane. Since gases are much simpler in terms of their structure and the methane gas makes up about 80% of natural gas (an extremely simple hydrocarbon) natural gas is much easier to use and requires less processing.

Crude oil is usually used for:

  • Gas
  • Heating oil
  • Diesel fuel
  • Commercial products (like plastics)
  • Jet fuel
  • Propane
  • Fuel for homes
  • Asphalt

Natural gas is usually used for:

  • Powering electrical grids
  • Heating of homes and businesses
  • Industrial processes


Northern Oilfield Services based out of Williston helps oilfield service companies with oil drilling rental equipment. Oilfield service companies are those companies who do the majority of the actual extraction of the oil from the ground, including fracing, drilling, and transporting. We help by supplying oilfield parts, such as for wellheads and valves. We also perform maintenance and testing services, ensuring your oilfield equipment is running smoothly and is compliant with state, local, and federal laws. Our mission is to help make your life easier. Contact us today to get started!