What do 'rig' and 'shale bed' here mean ?
1. What does 'rig' mean ?
However, the output of the shale firms has proved surprisingly robust, even though they have cut their number of rigs significantly since the peak last October (see chart).
Another sentence:- "Its main influence used to be OPEC, and particularly the Saudis, switching the taps on and off to try to rig the price".
2. Does 'shale beds' mean 'shale formations' (in the earth) ?
As American production continues to rise, pressure will grow on the government to ease its restrictions on exports of crude. In the meantime America’s imports are diving—they fell below those of China last month. Other countries, from Russia to Argentina, have promising shale beds.
Thanks
http://www.economist.com/news/business/21651267-american-shale-firms-are-now-oil-markets-swing-producers-after-opec