By Andy May
“Prediction is very difficult, especially about the future” (old Danish proverb, sometimes attributed to Niels Bohr)
In November, 2016 the USGS (United States Geological Survey) reported their assessment of the recent discovery of 20 billion barrels of oil equivalent (technically recoverable) in the Midland Basin of West Texas. About the same time IHS researcher Peter Blomquist published an estimate of 35 billion barrels. Compare these estimates with Ghawar Field in Saudi Arabia, the largest conventional oil field in the world, which contained 80 billion barrels when discovered. There is an old saying in the oil and gas exploration business “big discoveries get bigger and small discoveries get smaller.” As a retired petrophysicist who has been involved with many discoveries of all sizes, I can say this is what I’ve always seen, although I have no statistics to back the statement up. Twenty or thirty years from now when the field is mostly developed, it is very likely the estimated ultimate hydrocarbon recovery from the field will be larger than either of those estimates.
The technology for producing this sort of shale oil was invented very recently, well after Marion King Hubbert produced the “Hubbert curve” predicting that U.S. oil production would peak in the early 1970’s. As Daniel Yergin points out in The Quest:
“Hubbert got the date right, but his projection on supply was far off. Hubbert greatly underestimated the amount of oil that would be found – and – produced in the United States. By 2010 U.S. production was four times higher than Hubbert had estimated- 5.9 million barrels per day versus Hubbert’s 1971 estimate of no more than 1.5 million barrels per day.”
A comparison of actual oil production versus a version of Hubbert’s curve is shown in figure 5 (this curve is slightly different than the one Yergin used):
Figure 5, source
Technically Recoverable Reserves
So clearly Hubbert’s Malthusian curve did not predict oil supply correctly, new technology has allowed us to tap into oil that was not part of the potential supply when he did his calculation. Paul Ehrlich’s ominous 1968 prediction in The Population Bomb that 65 million Americans would starve to death in the 1980’s was incorrect for the same reason. He could not have predicted the green technology revolution that included natural gas based fertilizer (the Haber-Bosch process) and Nobel Prize winner Norman Borlaug’s new hybrid strains of wheat, rice and corn. Some might say, well Hubbert was wrong then; but what about tomorrow? Isn’t oil still a finite resource? Let’s examine that idea. Table 1 shows a rough estimate of the technically recoverable reserves of oil and gas known today, using only known oil and gas technology. More deposits will obviously be found and technology will improve in the future.
Table 1
The reserve estimates are in billions of barrels of oil equivalent. NGL and oil volumes are presented as is and natural gas is converted to oil-equivalent using the USGS conversion of 6 MCF to one barrel of oil. The table includes the “proven” worldwide oil, gas and NGL reserves from BP’s 2016 reserves summary. It also includes the 2012 USGS estimate of undiscovered “conventional” oil and gas reserves fully risked, the EIA estimate of unconventional shale oil and gas reserves, and the IEA oil shale (kerogen) and oil sands (bitumen) reserve estimates. Our estimate of 1,682 BBOE in world-wide unconventional shale oil and gas reserves is lower than the IEA estimate of 2,781. The spread in these estimates gives us an idea about how uncertain these numbers are. Our estimate of 781 BBO in oil sand bitumen reserves is lower than the IEA estimate of 1,000 to 1,500 BBO. So, please consider this table very conservative. Yet, it results in a 148-year supply!
The moral of the story? Never underestimate the ingenuity of mankind and never assume that technology is static. Also, the resources that technology recognizes today are not all the planet’s resources.