CHAPARRAL ENERGY, LLC

Incident Narrative

AT 11:50 AM ON THE MORNING OF MARCH 1, 2010 A CHAPARRAL ENERGY, LLC OPERATOR WORKING ON THE GROUNDS OF THE CHAPARRAL ENERGY ARKALON CO2 PLANT LOCATED IN HAYNE, KS HEARD VENTING CO2. THE EMPLOYEE PROCEEDED IMMEDIATELY TO INVESTIGATE THE CAUSE OF THE RELEASE AND FOUND THAT THE RELIEF VALVE ON THE CHAPARRAL ENERGY OPERATED HAYNE-BOOKER CO2 PIPELINE HAD RELIEVED AND THAT THE PIPE BELOW THE VALVE HAD FAILED CAUSING DAMAGE TO THE RELIEF SYSTEM. AT 11:51AM THE OPERATOR BEGAN SHUTTING DOWN THE CO2 PIPELINE, THE LINE WAS SHUT DOWN BY 11:55AM. INTERNAL INVESTIGATION OF THE ACCIDENT DETERMINED THAT THE FAILURE AND SUBSEQUENT LEAK OCCURRED DUE TO A DESIGN FLAW IN THE SUPPORT FOR THE RELIEF VALVE. THERE WAS NO OPERATOR/CONTROLLER ISSUES INVOLVED IN THE CAUSE OF THE INCIDENT. THE RELIEF VALVE SUPPORT HAS BEEN REDESIGNED TO ELIMINATE THE POSSIBILITY OF FUTURE REOCCURRENCES. THIS PROCESS HAS BEEN REPEATED ON ALL RELIEF VALVES ASSOCIATED WITH THIS LINE. THE NEW DESIGN HAS BEEN INCORPORATED INTO THE COMPANY DESIGN STANDARD TO PREVENT SIMILAR OCCURRENCES ON FUTURE LINES. REPAIRS WERE COMPLETED ON MARCH 5, 2010. STARTUP OF THE LINE COMPLETED AT 2:00PM ON MARCH 5. THIS IS TO CLOSE OUT THIS REPORT, NOTHING NEW TO REPORT.