Following the sale of substantial assets on the North Dakota Fort Berthold Reservation, Denver-based Whiting Petroleum Corp. is keeping its focus on the Bakken while growing its assets in Colorado's Denver-Julesburg (DJ) Basin and collectively maintaining 126,000 boe/d production next year, according to CEO Jim Volker.

Whiting reported more red ink in 3Q2017, but Volker said the company had "impressive results" from both the Bakken Shale (114,450 boe/d) and the Redtail Field (11,715 boe/d) in Colorado. Redtail drilling resulted in a 3Q2017 production increase of 78%, he said during a conference call with analysts Thursday.

In August, Whiting sold mostly non-operated Bakken assets to a subsidiary of upstart Calgary-based producer RimRock Oil and Gas Inc. for $500 million. The transaction included Whiting's Fort Berthold area assets that span 29,637 acres in Dunn and McLean Counties, ND, with 7,785 boe/d production, or 7% of Whiting's 2Q2017 output.

Volker said any further asset sales would be noncore and could include the new Redtail gas plant in Colorado when it is operational.

Volker outlined plans to limit maintenance capital spending to $650 million and still maintain production of 126,000 boe/d through next year, based on operations through the first 10 months of 2017.

"Efficiencies have been continued to improve our results," Volker said. "We're confident about the areas in which we're drilling through the end of the year and really through the end of 2018, so we're concentrating in the Williston Basin."

Some 90% of Whiting's nearly 500,000 net acres in the Williston is designated in the core of the Bakken, Volker said, adding that the company has not heavily drilled any of that acreage so far.

"We've watched our inventory of good reliable locations improve with technology and expand with technology, so we're very optimistic about essentially all of what we call our core area," he said.

"We have a great reservoir there, and we have a lot of oil in place and our good opportunities come from both new technology and new areas, meaning undrilled areas as well as areas where we may have some downspacing opportunities."

Whiting has nearly 135,000 net acres in the eastern DJ Basin in Colorado, where a spokesperson said the company is "rapidly growing" its Niobrara A, B, C, and Codell interval production with 5,400 potential gross drilling locations.

For 3Q2017, Whiting reported a net loss of $286.4 million (minus 79 cents/share), compared to a loss of $693.1 million (minus $2.47) for the same period last year.

It was scheduled to be Volker's final quarterly earnings report as CEO. Earlier in the week, Whiting named Brad Holly president and CEO, effective Nov. 1.