Shale

the green shales of a bean

Mr. Lyell next visited the red and green shales of Cabotville, north of Springfield in Massachusetts, where some of the best Ornithichnites have been procured, chiefly in the green shale.

As on all large green roofs, the soil is not dirt exactly but a gravel-like growing medium of granulated pumice, shales, clays and other minerals.

Five years in, ARPA–E’s priorities have shifted, too, for the same reason. The cheap natural gas freed from shale by horizontal drilling and hydraulic fracturing (or fracking) has helped kill off bleeding-edge programs like Electrofuels, a bid to use microbes to turn cheap electricity into liquid fuels, […]

American shale’s placid responses to energy whirlwinds are becoming an enduring feature of the U.S. oil industry. In recent years, public drillers under investor pressure to be profitable have treated spiking oil prices as an opportunity to return more cash to shareholders—and lock in prices for futures sales. A wave of consolidation has swept out the privately held operators that were quick to add new barrels when prices screened higher. The upshot is that companies aren’t likely to add new rigs unless oil prices hit between $75 and $85 a barrel and stay there for several months, analysts and executives say. […] So far, U.S. shale’s temperance has been a boon to Trump. A steady increase in U.S. production has helped soften spikes in crude prices after his campaigns against Venezuela and now Iran—both major oil producers. The Energy Information Administration expects the national oil output to have hit about 13.7 million barrels a day in February, up nearly 600,000 barrels from when Trump took office. But these gains have been the fruit of technical prowess in the field, not the pursuit of growth. Shale companies have become proficient at drilling fewer but much longer horizontal wells, which allows them to trim costs and still extract more crude. They routinely frack multiple wells at the same time and do so virtually around the clock, which also saves on costs.