UPDATE 1-North Dakota oil output tops 800,000 bpd in May
(Rewrites throughout, adds production history, comments from North Dakota's Mineral Resources Department)
July 15 (Reuters) - Oil production in North Dakota topped 800,000 barrels per day for the first time ever in May, preliminary data from the state regulator showed on Monday, as the number of rigs pumping crude in the state hit an all-time peak.
The state's Mineral Resources Department said output in May was up 2 percent - or 16,277 barrels per day (bpd) - hitting a record 810,129 bpd even as record rainfall for the month impeded new drilling.
Oil production in North Dakota has soared five-fold since 2008 as developments in horizontal drilling and hydraulic fracturing - commonly referred to as "fracking" - have allowed producers to tap the giant Bakken shale formation, transforming the state into the second largest oil producer after Texas.
There are now a record 8,915 producing wells in North Dakota, the Mineral Resources Department said, though the number of rigs drilling new wells in May increased by only one from April to 187, which was down 14 percent from the record level of 218 in the same month last year.
Well completions, whereby wells undergo hydraulic fracturing and are made ready to pump oil, rose by 10 in the month to 143.
"That number of completions is above the threshold needed to maintain production so oil production rate rose," the department said in a statement.
"Load restrictions have remained in place longer than ever before because May 2013 was the wettest on record."
The department said in April it expected production to accelerate only after May as rough weather and road restrictions in the months before limited activity. The state forecasts production of 850,000 bpd by early 2014.
(Reporting by David Sheppard; Editing by Bob Burgdorfer)