HOUSTON, May 17 (Xinhua) -- The number of active drilling rigs in the United States increased to 604 this week, up by one from the previous week but down by 116 from last year, according to the weekly data released by Houston-based oilfield services company Baker Hughes on Friday.
These active drilling rigs included 497 oil rigs operating in U.S. oil fields, up by one from the previous week; 103 gas rigs, unchanged; and four miscellaneous rigs, the same as last week.
