Understanding EOR: The New Method to Recover Oil Cost-Efficiently

The human use of petroleum, the precursor to gasoline, dates back to as early as 2000 B.C., when the paving material asphalt was used to build the biblical-age towers of Babylon. In 1859, United States citizen Edwin Drake struck oil in Pennsylvania, effectively kicking off what we now know as the contemporary industry of oil.

For its first four decades of use, petroleum was mainly filtered down into kerosene. After the internal combustion engine became grossly popular in the early 1900s, chemists and molecular engineers began toying around with petroleum to get better qualities of kerosene, gasoline, and other fuels, as well as never-before-discovered byproducts of the kerosene-creation process from crude oil.

Where is the oil industry at today?

Oil is still the same as it’s always been. However, modern society’s general attitude towards the unsustainability of crude oil has eroded over time. Today, car manufacturers are slowly phasing out gasoline- and diesel-powered vehicles in exchange for their up-and-coming electric-powered cousins. Since the industry is facing increased scrutiny from society in general, its constituency of workers and body of innovative researchers must continually develop new ways of doing things.

Put simply, the technologies at play in the oil business are many leaps and bounds ahead of their 100-year-old counterparts. One of the classes of technology that has improved is that of oil recovery, a term that refers to pumping oil out of wells deep below the Earth’s surface.

The most recently-developed solutions of oil recovery is that of enhanced oil recovery (EOR), a way to recover oil cost-efficiently.

Better understanding EOR

First, let’s differentiate between different types of oil recovery:

  • Primary – Oil reserves are pumped to the surface using pressurized pump jacks or on its own, without any human or machine assistance. In general, between five and 15 percent of oil is recovered via this method.
  • Secondary – Water or air is injected deep into the ground. After enough water or gas is forced into the reservoir, its oil shoots to the surface. This method can effectively drain reserves to a maximum of 35 and 45 percent. In other words, secondary oil recovery adds up to 30 percent greater extraction to reservoirs already targeted primarily.
  • Enhanced – Rather than using physical methods of extraction, this type of recovery involves changing the chemical properties of the oil.

Even further, there are three types of enhanced oil recovery. Fortunately, understanding EOR doesn’t require you to grasp the chemistry behind these methods.

Thermal recovery

This flavor of EOR is arguably the best way to recover oil cost-efficiently. Drillers create loads of steam and pump it into the reservoir. Hot oil is less viscous than cool or cold oil, meaning it flows with less restriction and more speed.

Gas injection

One of three gases – carbon dioxide, nitrogen, or natural gas – is injected thousands of feet below the Earth’s surface and into the reservoir. The viscosity of the oil does, in fact, increase, though it still is readily pushed to the surface.

Chemical injection

Unarguably the most controversial of these three methods, chemical injection uses highly-processed, general-toxic liquid mixes to change the properties of the oil. In particular, the oil’s surface tension decreases upon contact, thereby improving the effectiveness of flooding reservoirs with water to push the oil out.

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