ONEOK NGL PIPELINE, LLC

Incident Narrative

AT APPROXIMATELY 10:10 JULY 24, 2017 LOCAL TIME A WELL PUMPER CONTACTED THE ONEOK PIPELINE CONTROL CENTER TO REPORT HE HAD DISCOVERED AN ICE BALL OVER THE ONEOK ARTESIA LATERAL RIGHT OF WAY AT MILE POST 77. LOCAL ONEOK OPERATIONS PERSONNEL WERE DISPATCHED TO THE LOCATION AND CONFIRMED THE RELEASE WAS ON THE ONEOK 6"" ARTESIA LATERAL. ONEOK OPERATIONS PERSONNEL MONITORED THE LOCATION UNTIL THE LINE COULD BE SHUT DOWN AND DE-PRESSURED. THE ONEOK LINE WAS EXCAVATED FOR REPAIR, AND IT WAS DETERMINED THE CAUSE OF THE RELEASE WAS LOCALIZED CORROSION. ONEOK'S RECTIFIER AND GROUND BED PROVIDING CATHODIC PROTECTION CURRENT FOR THIS SEGMENT OF THE ARTESIA LATERAL HAD REACHED THE END OF THEIR EFFECTIVE LIFESPANS AND WERE SCHEDULED FOR REPLACEMENT IN THE THIRD QUARTER OF 2017. SIMULTANEOUSLY, ONEOK'S INVESTIGATION OF THE RELEASE DETERMINED THAT A PIPELINE OPERATOR WITH MULTIPLE ASSETS CROSSING AND SHARING RIGHT OF WAY WITH THE ARTESIA LATERAL HAD REPLACED AND INCREASED THE CURRENT OUTPUT OF ITS NEARBY DEEP WELL GROUND BED AND RECTIFIER. THESE CONDITIONS LED TO STRAY CURRENT INTERFERENCE, RESULTING IN THE CORROSION THAT WAS THE SOURCE OF THE RELEASE. ONEOK CORROSION SPECIALISTS AND TECHNICIANS WORKED WITH THE OPERATOR OF THE FOREIGN PIPELINES TO MITIGATE THE INTERFERENCE AS WELL EXPEDITING THE REPLACEMENT OF THE GROUND BED WHICH WAS COMPLETED ON JULY 27. THE DAMAGED SECTION OF PIPELINE WAS REMOVED AND REPLACED WITH NEW PRE-TESTED PIPE AND THE PIPELINE WAS RETURNED TO SERVICE ON AUGUST 2ND, 2017 AT APPROXIMATELY 11:00 AM.