What If We Never Run Out of Oil? - Charles C. Mann - The Atlantic - 0 views
-
In most cases, mining tar sands involves drilling two horizontal wells, one above the other, into the bitumen layer; injecting massive gouts of high-pressure steam and solvents into the top well, liquefying the bitumen; sucking up the melted bitumen as it drips into the sand around the lower well; and then refining the bitumen into “synthetic crude oil.”
-
Economists sometimes describe a fuel in terms of its energy return on energy invested (EROEI), a measure of how much energy must be used up to acquire, process, and deliver the fuel in a useful form. OPEC oil, for example, is typically estimated to have an EROEI of 12 to 18, which means that 12 to 18 barrels of oil are produced at the wellhead for every barrel of oil consumed during their production. In this calculation, tar sands look awful: they have an EROEI of 4 to 7. (Steaming out the bitumen also requires a lot of water. Environmentalists ask, with some justification, where it all is going to come from.)
-
To obtain shale gas, companies first dig wells that reach down thousands of feet. Then, with the absurd agility of anime characters, the drills wriggle sideways to bore thousands of feet more through methane-bearing shale. Once in place, the well injects high-pressure water into the stone, creating hairline cracks. The water is mixed with chemicals and “proppant,” particles of sand or ceramic that help keep the cracks open once they have formed. Gas trapped between layers of shale seeps past the proppant and rises through the well to be collected.
- ...13 more annotations...