Rigs targeting oil in the U.S. dropped by 13 this week after crude futures traded below $80 a barrel for the third time in a month. Rigs drilling for crude declined to 1,582, Baker Hughes Inc. (BHI) said today. Gas rigs were up 14 to 346, data posted on the Houston-based field services company’s website show. Miscellaneous rigs rose by one to one. U.S. benchmark West Texas Intermediate crude has tumbled by more than $20 a barrel in the last four months amid the highest domestic oil production levels since the 1980s. The slide in prices threatens to slow a drilling boom in U.S. shale formations that has helped drive down prices at the pump to the lowest levels since 2010 and shrink the nation’s dependence on foreign oil imports. “We’re seeing the impact of lower crude oil prices,” James Williams , president of WTRG Economics in London , […]