Crude became a volatile market in the 1980s after pricing deregulation and the start of its trading as a commodity. Combined, those factors allowed Wall Street and the Organization of Petroleum Exporting Countries, or OPEC, to largely determine oil prices. The rock-bottom price forced many independent drillers to halt production and close shop. I don't know how we did it. And not all of that crude is recoverable.
Oil is recovered in three stages.
Drillers rely on the earth's natural forces to push oil to the surface in the primary stage. In the secondary stage, that force is manufactured by pumping water down around the pockets of oil, pushing them upward. In the third, or tertiary, stage, carbon dioxide is commonly introduced into the reef, yielding the last remaining recoverable crude. But the deeper the crude, the more expensive the measures to recover it, whittling away at the profit. All of the efforts have yielded approximately 1.5 billion barrels of oil.