TRANSCONTINENTAL GAS PIPE LINE COMPANY — Gas transmission and gathering — incident on 2014-09-15

Gas transmission and gathering incident in LA. Reported cause: CORROSION FAILURE. Reported consequences: 0 fatalities, 0 injuries, 0.1 NATURAL GAS released, $475,000 reported property damage. Operator-reported incident data submitted to PHMSA, generally within 30 days. Records may be supplemented or corrected and do not represent final agency causal findings.

Report number: 20140105.

Operator ID: 19570.

Reported incident date: 9/15/2014 12:00.

Cause detail: INTERNAL CORROSION

Cause detail: WILLIAMS - TRANSCO DISTRICT MANAGER WARREN TOUPS WAS NOTIFIED BY DAN MCKNIGHT FROM HELIS ON 9-15-14 AT 9:15AM THAT THEY WERE INVESTIGATING SOME BUBBLES IN THE SS 47 AREA, NEAR WHERE THEIR 4" PIPELINE CROSSED OVER TRANSCO'S 26" LINE. DAN STATED THEY FIRST NOTICED THE BUBBLES ABOUT 3:30PM ON 9-13-14. THE BARELY VISIBLE SHEEN COVERED APPROXIMATELY 300 FEET WIDE BY 2600 FEET LONG WITH 50% COVERAGE. THEY REPORTED THE LEAK & SHEEN TO NRC AT 6:10PM, NRC #1095249. TRANSCO WAS INFORMED THAT HELIS HAD SHUT-IN AND BLOWN DOWN THEIR WELLS. THIS LED THEM TO BELIEVE THE BUBBLES WERE POSSIBLY COMING FROM THE TRANSCO 26" LINE. HELIS ALSO UTILIZED THE SERVICES OF OIL MOPS(OSRO) TO CONTAIN THE SHEEN AND THE SERVICES OF BLACKWATER DIVERS WHO HAD ARRIVED AT THE LOCATION EARLIER THAT MORNING. WE (TRANSCO) PLOTTED COORDINATES ON OUR ALIGNMENT SHEETS, BUT IT PLOTTED OUT ABOUT 1500 FEET FROM TRANSCO 26". OUR TECHNICIANS, WERE SENT OUT BY HELICOPTER TO FLY OVER LEAK SITE AND LAND AT SS 45 PLATFORM(HELIS OWNED). AT 11:35AM, OUR TECHNICIAN CALLED WITH DETAILS OF THE SHEEN WHICH WAS VERY LIGHT AND MEASURED 5 MILES LONG AND 300 FEET WIDE WITH ABOUT 30% COVERAGE. OUR TECHNICIAN RELAYED TO US UPDATED COORDINATES TAKEN BY THE HELICOPTER. HE TOOK A FIELD BOAT TO LEAK SITE AND WAS INFORMED BY BLACKWATER DIVERS THEY SUSPECTED THAT THE BUBBLES WERE COMING FROM TRANSCO 26" LINE. AT 1:35PM, TRANSCO SCHRIEVER OFFICE WAS INFORMED THAT BUBBLES WERE COMING FROM THE TRANSCO 26" PIPELINE. HELIS CALLED O'BRIENS AT 12 NOON ON 9-15-14 TO INFORM THEM THAT THE LEAK DID NOT BELONG TO HELIS. SCHRIEVER OFFICE ASSUMED THE ORIGINAL NRC #1095249 THAT HELIS HAD CALLED IN WOULD ALSO APPLY TO TRANSCO LEAK ON THE 26" PIPELINE. AFTER CONFIRMING WITH BUD KLINE AND WITH O'BRIEN'S THAT ANOTHER NRC # WAS NECESSARY, TOUPS CONTACTED O'BRIEN'S AT 3:13PM AND WILLIAMS (TRANSCO) GAS CONTROL AT 3:20PM. O'BRIENS CONTACTED NRC AT 3:35PM AND RECEIVED NRC #1095398. O'BRIEN'S ALSO CONTACTED LA. STATE POLICE AT 3:42PM AND RECEIVED #14-04128. SCHRIEVER DISTRICT PERSONNEL ISOLATED THE 26" PIPELINE SEGMENT 5103 AT SHIP SHOAL 70 PLATFORM AND AT DOG LAKE GENERATOR PLATFORM AT 4:22PM. NEGOTIATIONS CONTINUED BETWEEN TRANSCO & HELIS TO UTILIZE THE OSRO (OIL MOPS) AND BLACKWATER DIVERS AS WELL AS THE LIFT BOAT ON LOCATION THE DIVERS WERE USING. TRANSCO WAS ABLE TO UTILIZE OIL MOPS PERSONNEL AND EQUIPMENT, BUT NOT BLACKWATER DIVERS AND LIFT BOAT. SCHRIEVER THEN REQUESTED OIL MOPS PERSONNEL TO USE ABSORBENT BOOM TO ENCIRCLE THE BUBBLES, CAPTURING ANY SHEENING WITHIN THE BOOM. A DIVE VESSEL THAT WAS BEING USED BY TRANSCO ON ANOTHER JOB, WAS REQUESTED TO RELOCATE TO LEAK LOCATION AS SOON AS POSSIBLE. INCLEMENT WEATHER CAUSED SOME DELAYS WITH THE PIPELINE BLOWDOWN AND THE REPAIR. SUMMARY OF LEAK INVESTIGATION & REPAIR OF THE LEAK: DIVERS WERE SENT DOWN TO THE LEAKING PIPE, THEY PERFORMED A UT SCAN ON ALL SIDES OF THE LEAKING PIPE AND VERIFIED THAT THE THE LEAK WAS NOT EXTERNAL. THE LEAK OCCURRED ON THE LOW POINT OF THE PIPE, NEAR THE 6 O'CLOCK POSITION. A CLAMP WAS USED TO REPAIR THE LEAK AND THE LINE WAS GRADUALLY PRESSURED BACK UP TO MAOP ON 9-29-2014 AT 3:15 PM; NO LEAKS WERE DETECTED. THE HISTORY OF THIS GATHERING PIPELINE SYSTEM HAS BEEN THE TRANSPORTATION OF UNPROCESSED UNDEHYDRATED NATURAL GAS SINCE 1990. TRANSCO FOLLOWS HAS A STRICT INTERNAL CORROSION MONITORING AND CONTROL POLICY, THIS LINE HAS BEEN TREATED SINCE 1990 WITH CORROSION INHIBITORS AND BIOCIDES. SAMPLES ARE COLLECTED AND RESIDUALS ARE MONITORED MONTHLY. FIELD TECHNICIANS MEASURE CHEMICAL QUANTITIES AND CHEMICAL INJECTION PUMP OPERATIONS MONTHLY. INTERNAL CORROSION LEAK DOCUMENTATION IS PROVIDED TO ASSET INTEGRITY INTERNAL CORROSION ENGINEERS FOR RECOMMENDATIONS.

PHMSA trend classification: significant incident, not serious.

PHMSA standardized cause: CORROSION — INTERNAL.

PHMSA indexed costs: $606,950 reported total cost, $318,476.196 in 1984 dollars, $735,660.646 in current-year dollars.

PHMSA trend flags, standardized causes, and indexed costs are analytical fields added to operator-reported incident data. They do not represent final agency causal findings.