Denver-based DCP Midstream, which operates one of the largest natural gas processors in the country, on Friday announced it was cutting its workforce by 20% and closing a regional office.

The Oklahoma City office is to close, and the workforce is being reduced in the Tulsa office and Midland, TX, office. Functions would be primarily moved to Denver headquarters and the Houston regional office.

“With a 90-year history, we are repositioning ourselves for the long term and ensuring we have a sustainable workforce that meets our future needs,” said CEO Wouter van Kempen. “While this transition is difficult, we are establishing DCP for continued growth founded upon a culture of operational excellence.”

DCP Midstream is the largest oil and gas company and the largest private company in Denver. It operates in 18 states across major producing regions. The company has a 50-50 joint venture between Phillips 66 and Spectra Energy, and it owns the general partner of DCP Midstream Partners LP.

Since 2010, the operator has put in service close to $4 billion of capital projects in the country’s major producing basins. DCP Midstream LLC and DCP Midstream Partners LP are review 2015 financial plans during Spectra Energy Corp.’s analyst/investor meeting on Thursday.