Steven Lynch’s opinion piece published in the August 25, 2009 edition of the New York Times, “Peak Oil Is a Waste of Energy,” contends that there is no danger of near-term decline of production rates because great volumes of oil are believed yet to be discovered. This simplistic view fails to recognize that an aging handful of giant and super-giant fields (only 320 of the world’s 16,000 oil fields) provide nearly 60 percent of global oil supply. We provide an alternative view that field size, not just total undiscovered volumes, will determine future production rates and costs.

To illustrate this point, compare an oil field to a glass of water with a straw (our capital cost) as the means of extraction. A single glass of water can be drained by one straw at a very low cost. To drain the glass faster, add multiple straws for a higher extraction rate and higher cost. Consider that same volume of water poured onto a table. There are now many much smaller puddles that require their own straws. Not only is the unit cost of extracting each small puddle much higher than in the case of the glass, the productivity of each straw is much lower. In practice it is not possible to produce from the multiple puddles at the same rate as from the glass. We have “drunk” most of the oil from the giant and super-giant fields. What we have left are a few glasses and many, many puddles. Even though there may be many puddles yet to be discovered, it does not change the fact that they produce at a lower rate and at a higher cost than their larger brethren.

Current giant and super-giant fields are soon destined to be so depleted that no leap in technology or increase in price will prolong their life. Oil is a finite resource. Because the amount of oil has been underestimated in the past doesn’t mean it is today or will continue to be.

The estimates of the commercially recoverable oil found in fields discovered decades ago have been, in many cases, adjusted upward over time. This upward assessment is primarily attributed, in addition to increased field knowledge and production histories, to giant leaps in technology used to access and extract the oil. Those who cite this trend as proof that oil shortages are not a near-term threat are only correct in assuming that for much of their history, the giant and super-giant fields were under-utilized. However, they fail to acknowledge the trend’s limitations.

Regardless of the claims of the U.S. Geological Survey and others of a trillion barrels of undiscovered oil, let’s look at the recent history of finding giant and super-giant fields. The consistency of their contribution is largely the result of increased rates of extraction, not to new discoveries. As time passes, new discoveries are increasingly smaller, of lower quality and located in ever-more difficult operating environments. In the 1960s, 26 giant and super-giant fields were discovered. That number has consistently declined to only two so far in the first decade of the new millennium. The conditions necessary to create giants and super-giants occur infrequently, and where they do occur the real estate has, with few exceptions, been well explored. Trying as hard as they can to discover giant or super-giant fields, the oil companies’ results have been disappointing.

Because many countries (such as Russia and in the Middle East) keep information regarding their oil fields a state secret, many giant and super-giant fields may deplete much sooner than generally anticipated. The public does not know the forecast of production from these fields because there is no single repository of such information. It is shameful that we know so little about their state of depletion.

To say that we need not concern ourselves because we still have plenty of oil to exploit is simply irresponsible. There is insufficient information about the state of the giant and super-giant fields to make such a judgment. However, the statistics, depletion rate and rate of replacing giant and super-giant fields clearly indicate reduced future production capacity and increased price and cost.

The most pressing, but largely ignored question is when and at what cost? It’s time to put some real science in the forum and less hyperbole.

Kelley is the managing director, Bishop is executive director and chief geologist and Harrell is a senior adviser of RSK [UK] LIMITED, a petroleum consulting company with offices in Houston.