MID - VALLEY PIPELINE CO

Incident Narrative

AT APPROXIMATELY 08:00 ON OCTOBER 13, 2014 A PRESSURE DROP AND HIGH FLOW INDICATION WAS RECEIVED BY THE CONTROL CENTER ON THE LONGVIEW TO HAYNESVILLE SEGMENT OF THE MID VALLEY PIPELINE (MVPL). CONTROL CENTER SHUT DOWN THE PUMP UNITS AND CLOSED MOTOR OPERATED VALVES AT MP 30 AND 55. FIELD PERSONNEL WERE NOTIFIED IMMEDIATELY AND WERE DISPATCHED TO INVESTIGATE. HEAVY WEATHER IN THE AREA AT THE TIME HAMPERED THE FIELD INVESTIGATION. AT APPROXIMATELY 10:30 FIELD PERSONNEL IDENTIFIED CRUDE ON TETE BAYOU. AT APPROXIMATELY 11:44 THE FAILURE SITE WAS IDENTIFIED AND CONFIRMED. AT 13:17 NRC REPORT NO. 1098151 WAS FILED. SUBSEQUENT TO THIS NRC REPORT ANOTHER REPORT WAS FILED (1098153) AT 13:32 WITH AN UPDATED ESTIMATED VOLUME RELEASED. UPON EXCAVATION A FAILURE OF THE PIPE BODY LOCATED AT THE 6 O'CLOCK POSITION OF UNKNOWN CAUSE WAS IDENTIFIED. THE FAILED SECTION OF PIPE WAS CUT OUT AND PRESERVED FOR METALLURGICAL ANALYSIS ON OCTOBER 20, 2014. REPLACEMENT PIPE WAS INSTALLED ON THE SAME DATE. ON OCTOBER 25,2014 THE LINE SEGMENT WAS SUCCESSFULLY HYDROSTATICALLY PRESSURE TESTED FOR EIGHT (8) HOURS FROM MP 37.2 TO MP 62.8 PRIOR TO RESTART PER PHMSA ISSUED CORRECTIVE ACTION ORDER (CAO). PIPELINE WAS RESTARTED AT APPROXIMATELY 09:50 ON OCTOBER 26, 2014 UNDER A 20% REDUCTION IN OPERATING PRESSURE PER THE PHMSA ISSUED CAO. LINE CONTINUES TO OPERATE UNDER THIS PRESSURE REDUCTION. THE RESULTS OF THE METALLURGICAL ANALYSIS INDICATES THAT THE PIPE SECTION RUPTURED AT A COLONY OF AXIALLY-ORIENTED AND INTERLINKED NEAR-NEUTRAL-PH STRESS CORROSION CRACKS THAT WERE LOCATED WITHIN AN AREA OF EXTERNAL CORROSION AT THE 6:00 ORIENTATION.