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

HOUSTON, Oct. 13 (Xinhua) -- The number of active drilling rigs in the United States rose to 622 this week, up by three from the previous week but down by 147 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 501 oil rigs operating in U.S. oil fields, up by four from the previous week; 117 gas rig