TARGA DOWNSTREAM LLC

Incident Narrative

A TARGA PIPELINE TECHNICIAN DISCOVERED VAPOR RELEASING ON TARGA'S PEREGRINE PIPELINE ROW. THE PEREGRINE LATERAL TRANSPORTS Y GRADE NGL. AN INVESTIGATION DETERMINED THE RELEASE WAS COMING FROM TARGA'S PIPELINE AND THE PIPELINE WAS SHUT-DOWN AND DE-INVENTORIED USING A PIPELINE PIG PUSHED WITH NITROGEN. THE SEGMENT OF PIPELINE THAT FAILED IS A BORED SEGMENT INSTALLED BY DIRECTIONAL DRILL. THE LENGTH OF THE DRILL IS 926 FEET WITH A MAXIMUM DEPTH BELOW GRADE OF 70 FEET. REMOVING THE PIPELINE TO DETERMINE THE CAUSE OF THE FAILURE HAS BEEN DIFFICULT AND TIME CONSUMING BECAUSE OF THE DEPTH AND LENGTH OF THE DRILLED SEGMENT. A CORRODED AREA WITH PITTING THAT CREATED A HOLE IN THE PIPE WALL HAS BEEN FOUND AT THE LOCATION WHERE PIPE WAS 30 FEET BELOW GRADE. THE HOLE HAS BEEN MEASURED AT 3/8 INCH IN DIAMETER. AN INVESTIGATION WITH CORROSION SPECIALISTS IS ON-GOING TO DETERMINE THE CAUSE OF THE CORROSION. THE FAILED SEGMENT WILL ALSO BE SENT TO A METALLURGICAL LAB FOR ANALYSIS. TARGA WILL RUN AN IN-LINE INSPECTION OF THE PEREGRINE LATERAL TO ASSESS THE INTEGRITY OF THE PIPELINE ONCE THE FAILED SEGMENT IS REPLACED. EIGHT QUAIL WERE FOUND THAT WERE KILLED BY THE RELEASE. A TEXAS STATE WILDLIFE OFFICIAL WAS NOTIFIED. THE SECTION OF PIPE WHERE THE LEAK OCCURRED WAS INSTALLED BY A HORIZONTAL DIRECTIONAL DRILL. THAT SECTION WAS REPLACED BY A HORIZONTAL DIRECTIONAL DRILL. THE PIPELINE LOST COATING WHEN INSTALLED BY THE HORIZONTAL DIRECTIONAL DRILL DUE TO ROCKY SOIL CONDITIONS. EXTERNAL CORROSION WAS CAUSED BY DC STRAY CURRENT INTERFERENCE FROM A COMBINED OPERATION OF CATHODIC PROTECTION SYSTEMS FOR THE NEARBY PIPELINES MOST PREVALENT BEFORE CATHODIC PROTECTION FOR THE PIPELINE WAS ACTIVATED AFTER CONSTRUCTION. THE FOLLOWING MEASURES ARE BEING ADOPTED TO A PREVENT A SIMILAR ACCIDENT IN THE FUTURE. 1. ENHANCED DESIGN STUDY TO INCLUDE INVESTIGATING R.O.W. FOR INTERFERENCE ISSUES TO INCLUDE ANODIC/CATHODIC INTERFERENCE ALONG WITH THE PURPOSE OF AC/DC CATHODIC PROTECTION DESIGN. 2. ENHANCE NATIVE STUDY TO PROVIDE NATIVE READING AND TO INVESTIGATE ANY POSSIBLE INTERFERENCE ISSUES BEFORE CP IS COMMISSIONED. 3. INSTALL INTERIM GALVANIC CP SYSTEMS ON SEGMENTS INSTALLED BY HORIZONTAL DIRECTIONAL DRILL FOR TEMPORARY PROTECTION UNTIL PERMANENT CP SYSTEM IS ENERGIZED. THE ILI RUN AFTER REPAIR DID NOT IDENTIFY ANY ACTIONAL ANOMALIES.