ENTERPRISE PRODUCTS OPERATING LLC

Incident Narrative

A SEM-CRUDE LINE FLYER NOTIFIED ONEOK PIPELINE OF A FROST BALL IN THE SHARED CONWAY-ELDORADO ROW WHO IN TURN NOTIFIED ENTERPRISE. AN ENTERPRISE TECHNICIAN RESPONDED TO THE NOTIFICATION AND CONFIRMED THE FROST BALL APPEARED TO BE COMING FROM THE VICINITY OF THE ENTERPRISE LINE CONTAINING PROPANE ROW @ AM 56.5. THE AREA WAS THEN EXCAVATED AND ENTERPRISE PERSONNEL CONFIRMED A FROST BALL HAD FORMED AROUND THE EL DORADO 6"". THE PIPELINE WAS PURGED AND THE SEGMENT OF PIPE CONTAINING THE FROST BALL WAS CUT-OUT AND REPLACED. METALLURGICAL ANALYSIS OF THE FAILURE SEGMENT CONCLUDED THE SOURCE OF FAILURE WAS AN INTERNAL METAL LOSS FEATURE. IT IS SUSPECTED THAT THE PINHOLE TYPE FEATURE WAS PRE-EXISTING IN THE PIPELINE JOINT THEN GREW THROUGH ONE OR MORE INTERNAL CORROSION MECHANISMS - POSSIBLY FROM PRIOR CRUDE OIL SERVICE OR FROM HYDROSTATIC TESTING WATER REMAINING IN THE PIT. THE SMALL AND ISOLATED NATURE OF THE PIT MAKES THE EXACT CORROSION AND EVENTUAL FAILURE MECHANISM VERY DIFFICULT TO DETERMINE UNEQUIVOCALLY. THE FULL ANALYSIS OF THE PINHOLE FEATURE CONFIRMS THAT THE FEATURE IS BELOW DETECTION CAPABILITY OF CURRENT ILI TECHNOLOGY (~0.2 INCH LONG) AND WAS NOT DETECTED IN THE MOST RECENT 2008 ILI INSPECTION. ADDITIONALLY, THIS SEGMENT HAD A 49 CFR 195 SUBPART E HYDROSTATIC TEST AND SPIKE TEST (LOCAL PRESSURE EXPERIENCED 2152 PSIG WHICH IS 151% OF MOP), PERFORMED IN 2011, AND THE FEATURE SURVIVED THIS TEST. THE DEPTH OF THE PIT WAS SUCH THAT THE REMAINING FILAMENT EVENTUALLY FAILED DUE TO LOCALIZED OVERSTRESS (NOT CURRENTLY PREDICTABLE FROM PIPELINE OPERATING STRESS). THE RESULTS OF THE FAILURE ANALYSIS DO NOT INDICATE THE PRESENCE OF ANY PREVIOUSLY UN-IDENTIFIED THREATS TO THE OVERALL LINE. NOTE: REGARDING PART C 3.G YEAR OF MANUFACTURE: THE DATE OF THE PIPE MANUFACTURE IS UNKNOWN, HOWEVER, DUE TO LIMITATIONS WITH THE PHMSA FORM NOT ALLOWING AN UNKNOWN VALUE, THE YEAR OF MANUFACTURE IS ESTIMATED BASED ON THE YEAR INSTALLED.