OKLAHOMA CITY (AP) - An Oklahoma City-based oil and natural gas producer and 10 related companies have filed for Chapter 11 bankruptcy protection as they try to get rid of $1.2 billion in debt.

The Oklahoman (http://bit.ly/1ZB1EVM ) reports that Chaparral Energy Inc. filed for bankruptcy Monday, saying it continues to negotiate with lenders and bondholders to reduce its debt. The company says it has filed motions that would permit it to maintain operations as normal throughout the restructuring process.

The motions would allow the company to pay expenses associated with production operations and drilling and completion activities if approved by court.

CEO Mark Fischer says the depressed price environment along with the existing debt has severely limited the company's overall ability to operate.