HOUSTON, June 9 (Xinhua) -- The number of active drilling rigs in the United States fell to 695 this week, down by one from the previous week and by 38 from this time last year, according to the weekly data released Friday by Houston-based oilfield services company Baker Hughes.
The active drilling rigs included 556 oil rigs operating in U.S. oil fields, up by one from the previous week; 135 gas rigs, down by two from last week; and four miscellaneous rigs, the same as last week.
The rigs included 673 land drilling rigs, two inland water drilling rigs, and 20 offshore drilling rigs.
Of them, 51 were directional drilling rigs, 625 were horizontal drilling rigs and 19 were vertical drilling rigs.
So far, 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.