Number of active U.S. drilling rigs up this week

HOUSTON, July 7 (Xinhua) -- The number of active drilling rigs in the United States rose to 680 this week, up by six from the previous week but down by 72 from this time last year, according to the weekly data released by Houston-based oilfield services company Baker Hughes on Friday.

These active drilling rigs included 540 oil rigs operating in U.S. oil fields, down by five from the previous week; 135 gas rigs,