Texas oilman Jeffrey Brown has been pointing out to everyone that the supposed oversupply of crude oil isn’t quite what it seems. Yes, there is a large overhang of excess oil in the market. But how much of that oversupply is honest-to-god oil and how much is so-called lease condensate which gets carelessly lumped in with crude oil? And, why is this important to understanding the true state of world oil supplies?

Lease condensate consists of very light hydrocarbons which condense from gaseous into liquid form when they leave the high pressure of oil reservoirs and exit through the top of an oil well. This condensate is less dense than oil and can interfere with optimal refining if too much is mixed with actual crude oil. The oil industry’s own engineers classify oil as hydrocarbons having an API gravity of less than 45–the higher the number, the lower the density and the “lighter” the substance. Lease condensate is defined as hydrocarbons having an API gravity between 45 and 70.

Refiners are already complaining that so-called “blended crudes” contain too much lease condensate, and they are seeking out better crudes straight from the wellhead. Brown has dubbed all of this the great condensate con.

Brown points out that U.S. net crude oil imports for December 2015 grew from the previous December, according to the U.S. Energy Information Administration (EIA), the statistical arm of the U.S. Department of Energy. U.S. statistics for crude oil imports include condensate, but don’t break out condensate separately. Brown believes that with America already awash in condensate, almost all of those imports must have been crude oil proper.

Brown asks, “Why would refiners continue to import large–and increasing–volumes of actual crude oil, if they didn’t have to–even as we saw a huge build in [U.S.] C+C [crude oil plus condensate] inventories?”

Part of the answer is that U.S. production of crude oil has been declining since mid-2015. But another part of the answer is that what the EIA calls crude oil is actually crude plus lease condensate. With huge new amounts of lease condensate coming from America’s condensate-rich tight oil fields–the ones tapped by hydraulic fracturing or fracking–the United States isn’t producing quite as much actual crude oil as the raw numbers would lead us to believe. This EIA chart breaking down the API gravity of U.S. crude production supports this view. Exactly how much of America’s and the world’s presumed crude oil production is actually condensate remains a mystery. The data just aren’t sufficient to separate condensate production from crude oil in most instances.

Brown explains: “My premise is that U.S. (and probably global) refiners hit in late 2014 the upper limit of the volume of condensate that they could process” and still maintain the product mix they want to produce. That would imply that condensate inventories have been building faster than crude inventories and that the condensate is looking for an outlet.

That outlet has been in blended crudes, that is heavier crude oil that is blended with condensates to make it lighter and therefore something that fits the definition of light crude. Light crude is generally easier to refine and thus more valuable.

Trouble is, the blends lack the characteristics of nonblended crudes of comparable density (that is, the same API gravity), and refiners are discovering to their chagrin that the mix of products they can get out of blended crudes isn’t what they expect.

So, now we can try to answer our questions. Brown believes that worldwide production of condensate “accounts for virtually all of the post-2005 increase in C+C [crude plus condensate] production.” What this implies is that almost all of the 4 million-barrel-per-day increase in world “oil” production from 2005 through 2014 may actually be lease condensate. And that would mean crude oil production proper has been nearly flat during this period–a conjecture supported by record and near record average daily prices for crude oil from 2011 through 2014. Only when demand softened in late 2014 did prices begin to drop.

Here it is worth mentioning that when oil companies talk about the price of oil, they are referring to the price quoted on popular futures exchanges–prices which reflect only the price of crude oil itself. The exchanges do not allow other products such as condensates to be mixed with the oil that is delivered to holders of exchange contracts. But when oil companies (and governments) talk about oil supply, they include all sorts of things that cannot be sold as oil on the world market including biofuels, refinery gains and natural gas plant liquids as well as lease condensate. Which leads to a simple rule coined by Brown: If what you’re selling cannot be sold on the world market as crude oil, then it’s not crude oil.

The glut that developed in 2015 may ultimately be tied to some increases in actual, honest-to-god crude oil production. The accepted story from 2005 through 2014 has been that crude oil production has been growing, albeit at a significantly slower rate than the previous nine-year period–15.7 percent from 1996 through 2005 versus 5.4 percent from 2005 through 2014 according to the EIA. If Brown is right, we have all been victims of the great condensate con which has lulled the world into a sense of complacency with regard to actual oil supplies–supplies he believes have been barely growing or stagnant since 2005.

“Oil traders are acting on fundamentally flawed data,” Brown told me by phone.

Brown points out that it took trillions of dollars of investment from 2005 through today just to maintain what he believes is almost flat production in oil. With oil companies slashing exploration budgets in the face of low oil prices and production declining at an estimated 4.5 and 6.7 percent per year for existing wells worldwide, a recovery in oil demand might push oil prices much higher very quickly.

That possibility is being obscured by the supposed rise in crude oil production in recent years that may just turn out to be an artifact of the great condensate con.