ENTERPRISE PRODUCTS OPERATING LLC

Incident Narrative

AT 1528 HRS BOTH PUMPS AT FORSAN PUMP STATION ON THE SEMINOLE BLUE PIPELINE (LINE ID #1) SHUT DOWN WITH A DRASTIC LOSS OF PRESSURE AS NOTICED ON SCADA. THE CONTROLLER CONTACTED THE FIELD TECHNICIAN WHO ADVISED HE HAD JUST RECEIVED A CALL FROM A THIRD PARTY CONTRACTOR REPORTING A FIRE NEAR FORSAN STATION, IN HOWARD COUNTY, TX. SEMINOLE BLUE LINE WAS IMMEDIATELY SHUT DOWN AND ISOLATED. THE BIG SPRINGS FIRE DEPT WAS CONTACTED AND RESPONDED TO THE SITE. UPON ARRIVAL IT WAS CONFIRMED THAT THE UNDERGROUND PIPELINE HAD RUPTURED. THERE WERE NO INJURIES, EVACUATIONS, ROAD CLOSURES REPORTED, AND NO WATERWAYS WERE AFFECTED. METALLURGICAL ANALYSIS OF THE FAILURE SPECIMEN CONCLUDED ""THE FAILURE WAS CAUSED BY LONGITUDINAL STRESS CORROSION CRACKING (SCC). THE RUPTURE INITIATED AT A LONGITUDIANL STRESS-CORROSION CRACK IN THE HEAT AFFECTED ZONE (HAZ) OF THE LONGITUDINAL ERW SEAM. THE STRESS-CORROSION CRACK CONSISTED OF SEVERAL SHORTER CRACKS THAT COALESCED TO FORM ONE CRACK THAT WAS APPROXIMATELY 4.2 INCHES LONG. THE MAXIMUM DEPTH OF THE CRACK WAS 0.219 INCH, WHICH IS EQUIVALENT TO 87.6% OF THE NOMINAL PIPE WALL THICKNESS OF 0.250 INCH. IN CROSS SECTIONS THROUGH THE SCC CRACK AT THE FAILURE ORIGIN, THE PRESENCE OF SMALL TUNNELS IN THE PIPE STEEL NEAR THE FAILURE ORIGIN, OTHER CRACKS, AND EXTERNAL CORROSION PITS SUGGESTED THAT MICROBIOLOGICALLY INFLUENCED CORROSION (MIC) MAY HAVE OCCURRED. THE FAILURE PROPAGATED IN BOTH AXIAL DIRECTIONS FROM THE FAILURE ORIGIN, ARRESTING AT GW 2520 IN THE UPSTREAM DIRECTION, AND AT THE FILLET WELD OF A REPAIR SLEEVE IN THE DOWNSTREAM DIRECTION. VIRTUALLY ALL OF THE FAILURE (I.E., THE ORIGIN AND THE STRAIGHT, LONGITUDIANLLY ORIENTED PORTION OF THE PROPAGATED FRACTURE) WAS CONFINED TO THE HEAT AFFECTED ZONE OF THE HIGH-FREQUENCY ERW PIPE SEAM.