The Claims:

"... we only have 3 percent of the world's oil supplies ...

... we can't simply drill our way out of the problem ..."

-- Barack Obama - 9/26/08 - Presidential Debate (Transcript)

The claims that "we only have 3 percent of the world's oil supplies" and "that we can't simply drill our way out of the problem" have been made on numerous occasions by Barack Obama, Nancy Pelosi, Harry Reid, and a number of other prominent politicians.  The first statement is misleading at best, the second is demonstrably false under any interpretation.

United States Oil Supplies
Senator Obama used the term "world's oil supplies."  That could be interpreted to mean one of two different things, oil production rates or oil resources available. 

World oil production is about 83 million barrels per day.  The U.S. currently produces about 5 million barrels per day, or 6% of the world supply.

The U.S. could easily produce anywhere from the current 5 million barrels of oil per day that we do now to the equivalent of more than 26 million barrels per day.

World proved oil reserves total about 1.331 trillion barrels.  U.S. proved reserves total about 21 billion barrels, or less than 2% of world reserves.  However, proved oil reserves do not provide an accurate representation of the actual resources we have available.

The Energy Information Administration states the following:

What is not included in estimates of proved crude oil reserves?

Estimates of proved crude oil reserves do not include the following:

"Indicated additional reserves," a category of oil that is reported separately and may become available from known reservoirs through the application of improved recovery techniques using current technology

Natural gas liquids (including lease condensate)

Oil of doubtful recovery because of uncertainty as to geology, reservoir characteristics, or economic factors

Oil that may occur in undrilled prospects

Oil that may be produced from oil shales, coal, Gilsonite (asphalt), and other such sources

Stated in simpler terms, proved reserves only include conventional oil in fields that have already been drilled and were determined to be economical to produce at a time when oil prices were much lower than they have been for several years. 

U.S. proved reserves do not include the following:

Unproved recoverable reserves estimated at over 142 billion barrels.

ANWR 1002 area recoverable resources estimated at 10 billion barrels.

Offshore areas currently under moratorium estimated at 58 billion barrels recoverable.  Note that the moratorium expired October 1, 2008.

Stranded resources recoverable using EOR technology of over 100 billion barrels.

Heavy oil resources estimated at over 100 billion barrels.

Tar sand resources estimated at 60 - 80 billion barrels.

Oil shale deposits containing as much as 6 trillion barrels of oil equivalent.

Coal deposits containing as much as 6 trillion barrels of oil equivalent.

All of these resources together represent over 400 years worth of total world oil consumption at today's rate of about 83 million barrels per day and nearly 1,700 years of today's U.S. consumption of about 20 million barrels per day.  Granted, some portion of the trillions available may not be technically or economically recoverable, but at least 1/3 should be recoverable with oil anywhere near $100 per barrel, so it could be more like 566 years worth of current U.S. oil consumption or 133 years worth of current world oil consumption.

Findings
The fact is that the U.S. has massive quantities of domestic resources in deposits that are known to exist.  The problem, and the reason misleading claims that we do not have sufficient resources are made, is that outright bans have been placed on developing most of those resources and significant impediments have been placed on developing others.  Those bans and impediments allow someone to say that we only have 21 billion barrels of proved reserves, which is technically accurate, since it requires exploration and drilling to convert any of our abundant resources into proved reserves.

The fact is that we really could just drill our way to complete energy independence in a decade.  We could easily produce an additional one million barrels a day each year for the next 20 years and not only provide for all of our domestic needs, but also export as much as Saudi Arabia does today.

Conclusions
Senator Obama's claim that we only have 3% of the world's oil supplies is fiction.  Had he, or any of the myriad politicians who have made the same claim, said, "we have less than 2% of the world's proved oil reserves," we would have considered it to be technically accurate, although it would still be misleading and disingenuous at best.

Senator Obama's claim that we can't simply drill our way out of the problem is also fiction.  Had he, or any of the other politicians who have made the claim, said, "we don't want to drill our way out of this," instead of can't, it would have been completely accurate.

Additional Information and Resources:

Comprehensive Energy Independence Plan

Domestic Oil Production Plan

ANWR

Offshore

Oil Shale

Coal to Liquids

Heavy Oil/Tar Sands

Enhanced Oil Recovery