The number of drilling rigs operating in North Dakota’s oil fields fell to 159 on Monday, the lowest level since November 2010 and the latest reaction to falling crude oil prices, according to state data. Overnight the state lost eight rigs, a steep one-day drop not seen for years in the No. 2 U.S. oil producer. Rigs are typically contracted by oil producers to bore through the earth and create horizontal wells. The rigs then move on, and the wells are hydraulically fractured, or “fracked.” The number, which is tracked closely throughout North Dakota, comes after Continental Resources Inc, Oasis Petroleum Inc and other companies slashed planned spending for 2015, openly admitting they planned to use few rigs this year. The rig count is widely seen as a key barometer of an oil field’s health and longevity. More rigs means more […]