What did he really say?

Hubbert’s Curve ‘Piqued’ Interest

American Association of Petroleum Geologists (AAPG)
King Hubbert
King Hubbert

After asking a few questions of geologists of a generation or more ago, “Does the name M. King Hubbert ring a bell?” I often got the response:

“He must have been before my time.”

Two or three others said, “Was he the guy who said we’re running out of oil?”

King Hubbert did not say “we’re running out of oil.”

The media coined that phrase to create a sensational headline.

What he did say, in a paper given in 1956, was that at the then-present rate of discovery and development, current technology and the estimated ultimate, U.S. oil production would peak in the early 1970s.

Throwing Them a Curve

In this paper, titled “Nuclear Energy and Fossil Fuels,” Hubbert analyzed the status of coal, oil, gas and nuclear energy materials in the conterminous United States (politically correct term for the lower 48). He reminds us that fossil fuels exist in finite but as yet undefined quantities.

To examine the status and trend of the progress of consumption toward the ultimate of oil, he used the quasi-mathematical device known as the bell curve.

To construct a bell curve, two points are needed:

  • An initial zero – the beginning of production.
  • A second zero – because when the estimated volume has been consumed it would also be zero.
Hubbert's Peak
Hubbert's Peak

The bell curve serves well in dealing with commodities like oil and gas in which reserves are both added and used; the history of the dynamics of this commodity to 1956 establishes the horizontal and vertical scale. When the half-way point between zero and the ultimate has been reached, or is projected to have been reached, volume of the commodity has peaked.

As the process proceeds toward the ultimate (i.e. the right) downward side of the curve, it must be emphasized that Hubbert himself did not make the ultimate estimate in his graph. Rather he used estimates by Lewis G. Weeks and Wallace E. Pratt, two highly respected geologists and executives of Standard Oil of New Jersey and Humble Oil and Refining of Texas (later combined as Exxon), respectively.

Their separate estimates were very close together at about 150 billion barrels.

Hubbert, recognizing that technology of exploration and production were undergoing significant improvements, felt the estimate of 150 billion barrels was too low and arbitrarily added 50 billion barrels for an ultimate of 200 billion barrels.

The vectors toward these two ultimates are identified on the accompanying graphic. The larger ultimate extends the peaking point by about 15 years, from 1965 to the early 1970s.

What He Really Said

On Hubbert’s original 1956 graph (“figure 21” in the original work), the lower dashed curve on the right gives Hubbert’s estimate of U.S. oil production rates if the ultimate discoverable oil beneath the curve is 150 billion barrels. The upper dashed line, for 200 billion barrels, was his famous prediction that U.S. oil production would peak in the early 1970s. The actual U.S. oil production for 1956 through 2000 is superimposed as small circles.

Since 1985, the United States has produced slightly more oil than Hubbert’s prediction, largely because of successes in Alaska (not included in estimate of 1956) and in the far offshore Gulf Coast. (Hubbert’s Peak K. Deffeyes, Ch 1, p 3.)

For over 50 years additions exceeded withdrawals, and until World War II, the United States even exported oil. (It was our stopping of oil exports to Japan that triggered Japan’s attack on the United States.) Hubbert’s mathematical treatment of the dynamics of discovery, development and production results in a smooth curve for his figure.

Estimating an ultimate potential was a game that several credible sources played, but none had ventured or been so “rash” as to project the time of peaking. Rather than heed this warning bell and studying Hubbert’s reasoning and construction, the cry went out to “kill the messenger.”

Hubbert was immediately castigated in all manner of emotional criticism as an ivory tower researcher, a traitor to exploration. Many criticized his methodology, but in the 19709s, when production of oil did peak, there were a few red faces among his loudest critics.

Hubbert did not say in these words, “We are running out of oil.” What he did say was:

“... It is almost impossible to draw the production curve based upon an assumed (the then-current rate of finding and development and production technology) ultimate production of 150 billion barrels in any manner differing significantly from that shown in [his figure], according to which the curve must culminate at about 1965 and then must decline at a rate comparable to its earlier growth.

If we suppose the figure of 150 billion barrels to be 50 billion barrels too low – an amount equal to eight East Texas oil fields – then the ultimate potential reserve would be 200 billion barrels.

The second of the two extrapolations shown in his figure is based upon this assumption; but it is interesting to note that even then the date of culmination is retarded only until about 1970.

One other contingency merits comment.

By means of present production techniques, only about a third of the oil underground is being recovered. The reserve figures cited are for oil capable of being extracted by present techniques.

However, secondary recovery techniques are gradually being improved so that ultimately a somewhat larger but still unknown fraction of the oil underground should be extracted than is now the case.

Because of the slowness of the secondary recovery process, however, it appears unlikely that any improvement that can be made within the next 10 or 15 years can have any significant effect upon the date of culmination. A more probable effect of improved recovery will be to reduce the rate of decline after the culmination with respect to the rates shown in Figure 21.”

(“Nuclear Energy and Fossil Fuels,” 1956, pages 23-24.)

Although it is not shown on his figure, the national demand curve tracts the bell curve exactly until some time in the 1980s, when the bell curve begins to show decline in production capacity but the demand curve continues upwards at a steady angle. The ever-widening gap between supply and demand is filled by foreign imports.

Hubbert’s paper sounded the warning bell, but the government did nothing about it until about 1973, when they created the study committee chaired by Senator “Scoop” Jackson, who held open hearings on what to do about this energy “crisis.”

King Hubbert lived a hearty life until his death in 1989. He expanded his thinking and studies to world problems and was called on for lectures in most of the European countries, as well as governmental and professional societies in this country.

To his American audiences he emphasized the importance of developing alternate sources of energy, particularly atomic power, and that plans should be made for a network of atomic energy plants.

Again his urging has gone unheeded.

In David Doan’s memorial to Hubbert, he said, “At King Hubbert’s death, there was not a geologist, hydrologist, geophysicist, petroleum engineer or mineral economist in the entire world who was not deeply in his debt.”

Author’s note: This article would not have been possible without the enthusiastic and very effective help of Mary Kay Grosvald and Karen Piqune of AAPG’s Energy Resources Library.

For the article itself my loyal and longtime secretary Marguerite Bradford for her infinite patience in reading the research material and helping me compose the text itself. Charles Lujan, my personal aide, read to me a significant part of the library manuscripts.

Comments (1)

Remembering Hubbart
USA has again achieved it's peak daily production of over 9MMBO (last seen in 1970's). Hubbart's predictions were based on science which ... Read more
7/2/2015 7:06 AM
Arijit Chaudhuri

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James E. Wilson
James E. Wilson

Editor’s note: James E. “Jim” Wilson was a professional colleague and personal friend of King Hubbert.

Wilson worked for about 33 years with Shell Oil, and at age 44 was named vice president for exploration in Houston – the youngest vice president in the company’s history.

Since 1973, Wilson has been an active domestic and international consultant and an award-winning author.

He is a Sidney Powers medalist, past AAPG president and holds many other Association and professional honors.

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