(Adds gas and rig count data)
Sept 16 (Reuters) - U.S. oil output from seven major shale formations is expected to rise by 74,000 barrels per day (bpd) in October to a record high 8.843 million bpd, the U.S. Energy Information Administration said in its monthly drilling productivity report on Monday.
The largest change is expected in the Permian Basin of Texas and New Mexico, where output is seen climbing around 71,000 bpd to a record high 4.485 million bpd in October. That would be the ninth consecutive month of increases in the basin, its longest streak since December 2018.
Output in North Dakota and Montana’s Bakken region is expected to edge higher by about 2,000 bpd to a record 1.471 million bpd, the data showed, representing the smallest increase in the basin since May.
Even though the number of rigs drilling new wells in both the Permian and Bakken has declined since the start of the year, output has increased in both basins because the productivity of those rigs - the amount of oil new wells produce per rig - has increased to record levels.
Production increases in the Permian and Bakken have been at the forefront of a shale boom that helped make the United States the biggest oil producer in the world, ahead of Saudi Arabia and Russia.
Separately, U.S. natural gas output was projected to increase to a record 82.4 billion cubic feet per day (bcfd) in October.
That would be up almost 0.5 bcfd over the September forecast, putting production from the big shale basins up for a ninth month in a row even though the number of rigs in each region has declined since the start of the year.
Again that is because rig productivity - the amount of gas new wells produce per rig - was up in every region since the start of the year.
Output in the Appalachia region, the biggest U.S. shale gas formation, was set to rise about 0.2 bcfd to a record 32.8 bcfd.
The EIA said producers drilled 1,247 wells and completed 1,389 in the biggest shale basins in August, leaving total drilled but uncompleted (DUC) wells down 142 at 7,950, their lowest since November 2018.
That was the biggest monthly decline in DUCs since they fell by a record 144 in August 2016, according to data going back to December 2013.
Reporting by Scott DiSavino Editing by Marguerita Choy and Will Dunham