New lessons for an aging geologist
When I was a young geology student, I learned the basics of petroleum production as they were then understood. Deep layers of sedimentary rocks, including shale, were the “source rocks” for hydrocarbons. The source rocks were too difficult to exploit directly – it just wasn’t economical to mess with them.
But through natural processes, the petroleum and natural gas in the source rocks sometimes migrated to “reservoir rocks.” From Saudi Arabia to Texas, the name of the game was to sink wells into reservoir rocks and extract the hydrocarbons that had accumulated there over the ages.
But sustained high prices for petroleum and natural gas, as well as a revolution in drilling and extraction technology, have changed the game, making it possible to extract petroleum from what used to be dismissed as source rocks. And that’s making a world of difference in production. That point was brought home to me recently when I read that crude oil production in the U.S. is now greater than oil imports – the first time that’s been the case since 1995.
The U.S. Energy Information Administration, or EIA, recently published reports saying that oil imports stand at their lowest levels in absolute amounts compared to any time since 1991. That’s due, in part, to the technology of horizontal drilling at great depths underground, as well as hydraulic fracturing, nicknamed fracking.
Changes in the U.S. oil patch are garnering plenty of international attention. The International Energy Agency is the IEA -- not to be confused with our EIA. The IEA’s head of oil markets is Antoine Halff.
“Just a few years ago, everybody thought U.S. production was in permanent decline, that the nation had to face the prospect of continuously rising imports – (but) now the country is moving towards self-sufficiency,” Halff said to BBC News.
Some analysts say the U.S. may produce as much petroleum as Saudi Arabia six years from now while others think it won’t take that long. No one can predict the future with certainty, of course, but such estimates show just how much is changing in oil fields.
Natural gas production is also being revolutionized by fracking. Peter Brett of Shell Oil in the U.S. told BBC News, “It’s huge -- just five years ago we were talking about importing liquefied natural gas and bringing that in from overseas, and now we’re looking at self-sufficiency for the next 100 years in natural gas.”
To be sure, the boom in oil and natural gas alarms some people. Environmental costs are one concern, with fracking said to trigger earth tremors and threaten groundwater supplies when chemicals from the operations invade aquifers. Beyond that, of course, more petroleum and natural gas being burned means more carbon dioxide in the air.
But so far it looks like fracking is being accepted in many parts of the U.S., and, unless laws change, the new technology looks poised to bring us more hydrocarbons in the coming decades.
Dr. E. Kirsten Peters, a native of the rural Northwest, was trained as a geologist at Princeton and Harvard. This column is a service of the College of Agricultural, Human, and Natural Resource Sciences at Washington State University.