Houston-based independent Alta Mesa Resources Inc. and related companies, which are focused on Oklahoma’s myriad stacked formations, on Thursday filed for voluntary Chapter 11 bankruptcy protection.

The midstream platform Kingfisher Midstream LLC and subsidiaries are not part of the reorganization progress. Companies included in the petition are Alta Mesa Holdings LP, Alta Mesa Holdings GP LLC, OEM GP LLC, Alta Mesa Finance Services Corp., Alta Mesa Services LP and Oklahoma Energy Acquisitions LLC.

The Houston-based operator is developing the Sooner Trend of the Anadarko Basin, mostly in Canadian and Kingfisher counties, better known as the STACK.

“We believe that the Chapter 11 process provides the best pathway for Alta Mesa Resources and Alta Mesa Holdings to restructure their respective balance sheets and to regain the financial flexibility necessary to develop their large position in the STACK in a manner that will maximize value for all their stakeholders,” said Executive Chairman Jim Hackett.

Hackett, who led Anadarko Petroleum Corp. from 2004-2012, has chaired Alta Mesa since he led its takeover in 2017 and led the launch to become publicly traded last year. He stepped in as interim CEO earlier this year after the previous CEO, COO and CFO resigned.

The Securities and Exchange Commission in May said it was investigating Alta Mesa for possible financial reporting issues.

Even though Alta Mesa has made “considerable progress in reducing costs and improving well results, the companies continue to operate against a historically challenging commodity price environment,” management said.

The capital market also is “highly constrained for energy companies. Ultimately, these factors made bankruptcy protection the best option for the companies as they continue production operations while negotiating with their lenders.”

The board approved several leadership changes, including appointing a new CEO, to provide a “more optimal management structure” moving forward. Hackett would remain involved with the board and management team during the restructuring process.

Previous interim Executive Vice President (EVP) Mark Castiglione, who has overseen strategy and corporate development, was promoted to CEO.

Castiglione, Hackett said, “has demonstrated the skills required to lead this organization into the future, and he has the full support of the board. Mark has both a financial and technical background and has served in engineering and business development roles in several large- and medium-sized public and private independent oil and gas companies.”

Castiglione has been a partner at Meridian Energy LLC and previously was an adviser for MPC Resources LLC, as well as formerly for SandRidge Energy Inc.

In other management moves, interim President Randy Limbacher was named EVP of strategy and is to provide strategic counsel.

Interim COO John Campbell was promoted to president and COO. EVP Kim Warnica remains general counsel, chief compliance officer and secretary, while EVP John Regan is retaining his CFO title.

“When I assumed the interim chief executive officer role, I said that we would endeavor to find the right individual to lead the organization as it continues to progress forward with the development of our asset base,” Hackett said.