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The World's Oil Supplies: Total Resources Versus Reserves

Lensa Welch has been writing on HubPages for over nine years. Her articles typically focus on the medical sciences.

The Political and Social Debate: How Much Oil Is Left?

Oil Dependence. Energy independence. Green energy. Non-renewable. Not much left. Reserves. Resources. What does it mean? These words are being used frequently in conversations and in media. In today's political climate we are hearing these words with ever-increasing frequency. We have democrats accusing republicans, republicans accusing democrats, and media personalities on all sides pointing fingers, tossing out numbers, and creating accusations that the "other side" has lied.

With all of the terms that are used it is difficult to know who is correct. In order to critically examine the energy issues and make an informed decision, we need to know what some of the vocabulary means. Scientific definitions are often different and/or more specific than everyday connotative definitions. This is the case when examining scientific uses of the words resources and reserves. When the media reports the world's resources have some many years left it is very different from stating that the world's reserves have so many years left. Let's explore these two words so that you can have a deeper understanding of reports on energy supplies.

A Story About Ohio Oil

In the early days of oil in the United States, Ohio was a large oil producer. In 1886 it was considered the "middle east" of oil, producing 24 million barrels of oil. Now when you drive around the only sign of oil production is a few lonely oil pumps scattered around rural areas. It is easy to think that this means that Ohio's oil simply ran out. The real explanation is much more complicated. Once oil was found in Ohio, people began building oil wells everywhere. It is likely that you have seen oil drilling in movies or on television. When the supply of oil is hit, it gushes out of the ground as a giant, black oil geiser. Underground oil is under pressure. When a hole is poked in the supply, it squirts out that hole. The more holes are poked, the less pressure is available. It is kind of like the water in your house, the more water is running, the less pressure is available. After time passed there were large numbers of drill sites. This lowered the oil pressure. Taking the oil out of the ground reduced the pressure further. Soon it was very difficult for companies to get any oil out of their drill sites. The oil wells were closed and the oil industry ended. There was still lots of oil left under the ground, but it was no longer reachable.

Now, over a hundred years later, we have the technology to re-pressurize the wells. The problem is that the wells were not capped well in the late 1800s and early 1900s. If the wells are pressurized, the plugs will likely pop out and oil will be everywhere. Ohio is upping production with new technology, but the reserves are still much smaller than the available resources.

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Resources Versus Reserves

The story makes an important point. Resources are not reserves. These two words are sometimes used interchangeably in media. Sometimes these words are used for political arguments that make little sense when you know the definitions of these two words. One political side will say we only have so many reserves and then the other side counters that they are wrong, our resources are vast and that we are only using a small percentage of those resources. Due to definitions, both parties are right. It is not a lie to say that our reserves are expected to last 30–40 more years. This is true because despite vast resources our reserves are only a small portion of the available oil.

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What Are Reserves?

Reserves are the natural resources that with today's technology are able to be recovered at a profit. Oil reserves only cover oil that is discovered, confirmed, and able to be obtained economically. Reserves do not count oil that is:

  • Unable to be accessed with current technology
  • On property that does not allow drilling (private land, national parks, and etc.)
  • Unable to be accessed without violating laws
  • Unable to be economically viable

Physical Geology by Plummer, et al. (2010) places current estimates of the world's recoverable oil at around 1,000 billion barrels. Glen Kessler of the Washington Post notes that the United States currently has 22 billion barrels of oil reserves, a number that has been fairly constant since the 1940s. (The United States hit a peak of 40 billion barrels in 1970.)

What Are Total Resources?

Total resources are much larger than reserves because resources include all of the oil that current research shows should exist. This includes:

  • Oil that is not economical to obtain
  • Oil on private property
  • Oil on government property (national parks)
  • Oil that current laws or environmental restrictions block
  • Oil that theoretically should be there but has not been proven
  • Oil that current technology cannot reach (think of the Ohio story)

Think of some of the difficult places that we find oil: under the seafloor, in sub-arctic settings, or wedged in between individual layers of shale rather than in a pool. None of this oil is counted as reserves. Plummer, et a. note that the USGS estimates that there are around 2,300 billion barrels (including the reserve) of oil resources. Kessler writes that the U.S. is estimated to have 160 billion barrels within its borders.

Critically Analyze What You See and Hear

Knowing the difference between reserves and resources explains the media outcry on both sides about oil. When you read articles, see news, or hear speeches pay attention to the wording. Each side will use resources or reserves depending on the argument that is being made. Next time you hear one political side say, "Our reserves are only a tiny percent of the world's resources," followed by the other side saying, "They are wrong! The United States oil resources are a hundred time larger!" you can chuckle knowing that both sides are telling the truth.

This content reflects the personal opinions of the author. It is accurate and true to the best of the author’s knowledge and should not be substituted for impartial fact or advice in legal, political, or personal matters.

© 2012 Lena Welch

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