BP PIPELINE (NORTH AMERICA) INC.

Incident Narrative

ON JULY 26, 2013 A BP PIPELINE TECHNICIAN UPON EXITING THE PIPELINE OFFICE IDENTIFIED A LOSS OF PRIMARY CONTAINMENT OF CRUDE OIL IN THE BLAKE PUMP STATION OF THE BP #1 CRUDE SYSTEM. THE TECHNICIAN CONTACTED THE CONTROL CENTER WHICH IMMEDIATELY SHUT DOWN THE PIPELINE. ANALYSIS HAS DETERMINED THAT A PARTIALLY BURIED VALVE EXPERIENCED A MECHANICAL FAILURE OF A THREADED CONNECTION IN ITS CAST BODY. IT IS BELIEVED THAT A PRE-EXISTING FLAW IN THE 1950'S VINTAGE VALVE BODY CASTING REDUCED THE THREADED ENGAGEMENT LENGTH, DIMINISHING THE FRICTIONAL FORCES RETAINING THE 1/2' PLUG ALLOWING IT TO BACK OUT. THE IMPACTED AREA WAS REMEDIATED AND THE VALVE WAS REPLACED. THE METALLURGICAL CAUSE OF THE LEAK COULD NOT BE CONCLUSIVELY DETERMINED PRIMARILY BECAUSE THE PLUG WAS NOT RECOVERED FROM THE LEAK SITE. FIVE POSSIBLE FAILURE SCENARIOS WERE CONSIDERED AND ARE DISCUSSED BELOW. FAILURE SCENARIOS 1, 4, AND 5 CAN BE RULED OUT. FAILURE SCENARIO 1 ' THE PLUG WAS NEVER INSERTED FOLLOWING MAINTENANCE IN 2002. THIS SCENARIO WAS RULED OUT BASED ON BACKGROUND INFORMATION FROM BP. THE VALVE WOULD HAVE LEAKED IF THE PLUG WAS NOT IN THE DRAIN PORT, AND THE LEAK WOULD HAVE BEEN DISCOVERED. FAILURE SCENARIO 4 ' THE PLUG BLEW OUT DURING OPERATION. THIS SCENARIO WAS RULED OUT SINCE THE THREADS OF PORT 1 WERE NOT SHEARED OFF. THERE WAS NO EVIDENCE OF MECHANICAL DAMAGE TO THE THREADS TO SUPPORT THIS SCENARIO. FAILURE SCENARIO 5 ' COMPLETE CORROSION OF THE INTERNAL THREADS OCCURRED AND THE PLUG FELL OUT. THIS SCENARIO WAS RULED OUT SINCE ONLY A PORTION OF THE THREADS OF PORT 1 WAS CORRODED, AND A MAJORITY OR ALL OF THE THREADS THAT WOULD HAVE BEEN IN CONTACT WITH THE PLUG WERE NOT SIGNIFICANTLY CORRODED. FAILURE SCENARIO 3 ' THE PLUG BLEW OUT DURING OPERATION BECAUSE THE THREADS WERE CORRODED. THIS SCENARIO HAS A LOW LIKELIHOOD. SINCE ROLLED MATERIAL, WHICH COULD BE SIMILAR TO THE MATERIAL OF A CARBON STEEL PLUG, WAS SELECTIVELY ATTACKED, IT IS POSSIBLE THAT A CARBON STEEL PLUG COULD HAVE BEEN ATTACKED. ALSO, IT IS POSSIBLE THAT A NON-CARBON STEEL PLUG, THAT IS ANODIC TO STEEL, WAS INSERTED DURING THE MAINTENANCE IN 2002. SINCE THE OTHER TWO DRAIN PLUGS WERE DETERMINED TO COMPOSED OF CARBON STEEL, THIS IS NOT LIKELY. THEREFORE, THIS SCENARIO IS POSSIBLE, BUT IS NOT CONSIDERED LIKELY. FAILURE SCENARIO 2 ' THE PLUG BACKED OUT DURING OPERATION. THIS SCENARIO IS THE MOST LIKELY OF THE FIVE SCENARIOS. SUPPORTING EVIDENCE FOR THIS SCENARIO INCLUDES THE FACT THAT, ACCORDING TO BP, THE VALVE WAS SUBJECTED TO VIBRATIONS AND 2) THE THREADS OF THE PORT THAT LEAKED ARE NOT COMPLETELY CORRODED AWAY OR SHEARED OFF. AS DESCRIBED ABOVE, THERE WAS NO MECHANICAL DAMAGE OF THE THREADS TO SUPPORT SHEARING OFF AND A MAJORITY OR ALL OF THE THREADS THAT WOULD HAVE BEEN IN CONTACT WITH THE PLUG WERE NOT SIGNIFICANTLY CORRODED. THIS SCENARIO IS THE MOST POSSIBLE, IT'S BELIEVED TO BE VIBRATION AND COULD NOT BE DEFINITIVELY CONFIRMED.