HOUSTON, July 1 (Xinhua) -- The number of active drilling rigs in the United States decreased to 750 this week, down by three from the previous week but up by 275 from last year, according to the weekly data released Friday by Houston-based oilfield services company Baker Hughes.
These active drilling rigs included 595 oil rigs operating in U.S. oil fields, up by one from the previous week; 153 gas drilling rigs, down by four from last week; and two miscellaneous rigs, the same as last week.
The rigs included 730 land drilling rigs, three inland water rigs, and 17 offshore drilling rigs.
Of them, 43 are directional drilling rigs, 682 are horizontal drilling rigs and 25 are vertical drilling rigs.
The Permian Basin in western Texas and eastern New Mexico has been the largest source of shale oil production growth in the United States, having become an engine of supply growth outside the Organization of the Petroleum Exporting Countries in the past years.
