MIDCOAST GATHERING (NORTH TEXAS) L.P.

Incident Narrative

THE COMPRESSION AT THE MIDCOAST SPRINGTOWN PLANT SHUT DOWN DUE TO A POWER FAILURE. THE PLANT IS APPROXIMATELY 350 YARDS FROM THE SPRINGTOWN PIPE YARD WHERE THE RELIEF VALVE ON 2ND CAG WENT OFF AT SET PRESSURE (490 PSIG). GAS CONTROL RECEIVED AN ALARM THAT THE DECATUR COMPRESSOR SHUT IN AND WEATHERFORD PLANT CALLED GAS CONTROL THAT THEY WERE LOSING INLET VOLUME. GAS CONTROL CALLED PLANT OPERATOR TO GO TO SPRINGTOWN PLANT TO CHECK ON COMPRESSION AT 3:00 AM. AT 3:15 AM POLICE CALLED GAS CONTROL THAT THERE WAS GAS RELIEVING AT THE SPRINGTOWN PIPE YARD. MIDCOAST EMPLOYEE ARRIVED AT THE SPRINGTOWN PLANT AND HEARD RELIEF VALVE GOING OFF AT 3:30 AM (CONFIRMATION BY THE OPERATOR). MIDCOAST OPERATIONS TECH WAS CALLED TO INVESTIGATE THE RELIEF VALVE AND VERIFIED THE RELIEF VALVE ON 2ND CAG WAS RELIEVING AT 4:23 AM. OPERATION TECH OPEN BLOCK VALVE TO SWITCH 2ND CAG GAS INTO SM-12 PIPELINE AND THE RELIEF VALVE CLOSED AT 4:45 AM. THE RELIEF VALVE HAD RELIEVED AT 490 PSIG AT SET PRESSURE. RELIEF VALVE INFORMATION: MAKE: CONSOLIDATED, MODEL # 3910R-4-CC-V-65 SIZE 6' X 8' X8' MIDCOAST PERSONNEL (OPERATIONS, GAS CONTROL, IT,) PERFORMED A IN HOUSE INVESTIGATION AND HAS IDENTIFIED THAT WE WILL INSTALL A LOW LOW ALARM AT THE 4TH CAG TO SM-12 PIPELINE TO GIVE AN ALARM AT 30,000N MCF TO INFORM GAS CONTROL TO CALL OUT PERSONNEL TO THE SPRINGTOWN PLANT (ONLY MANNED DAYLIGHT HOURS) TO CALL SOMEONE OUT. THIS SHOULD PREVENT TISE FROM OCCURRING AGAIN. PREVENTION OF RECURRENCE TO PREVENT THIS FROM HAPPENING AGAIN A COMMITTEE REVIEWED THE INCIDENT AND DETERMINED THE FOLLOWING WILL BE IMPLEMENTED. AUTOMATE THE BYPASS VALVE TO OPEN AND COMMON UP THE SUCTION AND DISCHARGE HEADERS. SETTING PRESSURE TO OPERATE BELOW RELIEF VALVE SETTING. INSTALL A CHECK VALVE DOWNSTREAM OF THE PSV TO PREVENT ANY BACKFLOW IN THE EVENT SPRINGTOWN'S DISCHARGE LINE PRESSURE IS HIGHER THAN SPRINGTOWN'S SUCTION LINE PRESSURE. CHANGE THE METER RUN COMMUNICATION TO ALLOW GAS CONTROL THROUGH SCADA TO SEE NO FLOW ON THE SUCTION LINE TO SPRING TOWN. AFE HAS BEEN APPROVED, ENGINEERING HAS ORDERED PARTS AND SET UP A WORK ORDER. GAS CONTROL'S INCIDENT REVIEW CONTROLLER DIDN'T RECOGNIZE COMPRESSOR UNITS WERE DOWN DUE TO THE COMMUNICATIONS OUTAGE. REVIEWED THE GAS CONTROL AND OPERATIONS MEETING MINUTES AND SCADA CHANGES MADE. REVIEWED GAS CONTROL'S COMMUNICATION OUTAGE PROCEDURE. REVIEWED CORRECTIVE ACTIONS: GAS CONTROL WILL NOTIFY ON-CALL OPERATOR IF COMMUNICATION OUTAGE OCCURS AT SPRINGTOWN PLANT. CORRECTIVE ACTIONS 11/13/2019 GAS CONTROL CHANGE THE COMMUNICATION OUTAGE SETPOINT TO 30 MINUTES FROM 60 MINUTES. MOVE THE 4TH CAG OUTLET METER TO A SEPARATE COMMUNICATIONS PATH SO EITHER INLET OR OUTLET OF COMPRESSOR STATION CAN BE SEEN IF FUTURE COMMUNICATION OUTAGE OCCURS. CONTROLLER WILL NOTIFY FIELD PERSONAL IF COMMUNICATION OUTAGE OCCURS. FIELD INSTALLED A PRESSURE CONTROL VALVE TO SHUT GAS IN AT A PRESSURE SET POINT. INSTALLED A CONTROL VALVE TO RE-ROUTE GAS TO A DIFFERENT PIPELINE AT A PRESSURE SET POINT.