ANR PIPELINE CO — Gas transmission and gathering — incident on 2015-04-14

Gas transmission and gathering incident. Reported cause: CORROSION FAILURE. Reported consequences: 0 fatalities, 0 injuries, 1 NATURAL GAS released, $310,000 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: 20150065.

Operator ID: 405.

Reported incident date: 4/14/2015 17:25.

Cause detail: EXTERNAL CORROSION

Cause detail: ON 14 APRIL 2015 AT 17:15 CDT, A LEAK ON A TC OFFSHORE (TCO) PIPELINE RISER WAS DISCOVERED BY THE OWNER / THIRD PARTY PRODUCER, OF THE PLATFORM (THIRD PARTY) LOCATED IN OUTER CONTINENTAL SHELF SHIP SHOAL BLOCK 219 (SS219). THE LEAK DISCOVERY WAS IDENTIFIED BY AN AUDIBLE RELEASE OF GAS EMANATING FROM BENEATH A RISER CLAMP AND REPORTED TO TRANSCANADA/ANR PIPELINE COMPANY (ANR), OPERATOR FOR TCO. THE LEAK WAS LOCATED ABOVE THE WATER LINE ON THE PIPELINE RISER AT MILEPOST 0 ON THE 763 TRANSMISSION LINE TO A PLATFORM OWNED BY THE THIRD PARTY, RENAISSANCE ENERGY. THIS PLATFORM IS LOCATED AT COORDINATES; 28.506467, -91.101507. FOLLOWING THE DISCOVERY LEAK, THE PIPELINE SECTION WAS ISOLATED AT 16:50 CDT FROM THE THIRD PARTY PRODUCER AT SS219 ISOLATING THE SEGMENT FROM SS219 TO SHIP SHOAL BLOCK 204. THE LEAK WAS REPORT TO TRANSCANADA BY THE PRODUCER AT 17:25 CDT ON 14 APRIL. THE INCIDENT WAS REPORTED TO THE NATIONAL RESPONSE CENTER ON 14 APRIL 2015 AT 19:15 CDT. FOLLOWING THE REPORT OF THE INCIDENT TO THE NATIONAL RESPONSE CENTER, ANR MAINTAINED CONTACT AND UPDATED U.S. COAST GUARD, BSEE, AND PHMSA. THE PIPELINE WAS BLOWN DOWN AND FLARING PROCEDURES WERE INITIATED ON 16 APRIL 2015. NO SHEEN OR PRODUCT WAS OBSERVED DUE TO THE LEAK. ON 1 MAY 2015, PERSONNEL WERE DISPATCHED TO THE INCIDENT LOCATION TO REMOVE THE PIPELINE RISER CLAMP AND EVALUATE REPAIR OPTIONS FOR THE LEAK LOCATION. FOLLOWING THE REMOVAL OF THE CLAMP, THE LEAK AREA WAS SANDBLASTED, INSPECTED, AND EVALUATION THROUGH NON-DESTRUCTIVE EXAMINATION (NDE). ANALYSIS DETERMINED THAT THE LEAK WAS CAUSED BY CORROSION PITTING DUE TO EXTERNAL CORROSION UNDER THE RISER CLAMP. TO REPAIR THE LEAK, FULL ENCIRCLEMENT SLEEVE AND WELD WERE INSTALLED ON THE PIPELINE ACCORDING TO TRANSCANADA'S PROCEDURE. FOLLOWING THE INSTALLATION ADDITIONAL NDE WAS PERFORMED TO ENSURE THE ACCEPTABLE REPAIR WAS CONDUCTED. ON 11 MAY 2015 AT 12:40 CDT, THE PIPELINE WAS PURGED, RELOADED, AND PUT BACK INTO SERVICE.

PHMSA trend classification: significant incident, not serious.

PHMSA standardized cause: CORROSION — EXTERNAL.

PHMSA indexed costs: $311,405 reported total cost, $156,819.474 in 1984 dollars, $384,589.398 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.