CENTURION PIPELINE L.P.

Incident Narrative

ON MARCH 12, 2021, AT APPROXIMATELY 13:00 CST, A CENTURION PIPELINE L.P. (CPL) EMPLOYEE DISCOVERED A LEAK IN CPL'S MIDLAND STATION NEAR MIDLAND, TEXAS IN MIDLAND COUNTY, TEXAS. CPL DETERMINED THE SOURCE OF THE LEAK TO BE THE 12"" INLET GATE VALVE ON TANK #2421 AND IMMEDIATELY ISOLATED THE LEAK. HOWEVER, 10 BARRELS OF CRUDE OIL WERE RELEASED, OF WHICH, NINE (9) BARRELS WERE PROMPTLY RECOVERED IN LIQUID FORM. CPL REMEDIATED THE CONTAMINATED SOIL ON SITE. NO INJURIES, FATALITIES, OR FIRES WERE ASSOCIATED WITH THIS INCIDENT. CPL REPORTED THE LEAK TO THE TEXAS RAILROAD COMMISSION, OFFICE OF PIPELINE SAFETY AT 13:38 CST ON MARCH 12, 2021, AND WAS ISSUED INCIDENT NUMBER 2388 IN REFERENCE TO THE INCIDENT. AT THE TIME OF THE IS WRITING, CPL IS IN THE PROCESS OF CONDUCTING THE ROOT CAUSE FAILURE ANALYSIS. THE RESULTING INFORMATION RELATED TO THE CAUSE OF THE LEAK, PREVENTATIVE AND MITIGATIVE MEASURES (P&M), AND ANY ADDITIONAL COSTS ASSOCIATED WITH REPAIRING THE VALVE WILL BE SUBMITTED VIA SUPPLEMENTAL REPORT(S). SUPPLEMENTAL FINAL FILED ON 05/26/2021: UPDATED PART G1-7 AND PART G1-8. DURING THE ROOT CAUSE FAILURE ANALYSIS, CPL DETERMINED THAT UNDER-DEPOSIT MICROBIOLOGICALLY INFLUENCED CORROSION (MIC) CAUSED THE FAILURE. THE CONTRIBUTING FACTORS INCLUDE WATER DROP-OUT, SOLID DEPOSITS, AND AN UNUSUAL AMOUNT OF PARAFFIN ACCUMULATION ON THE BOTTOM OF THE TANK AND INLET VALVE. LOW FLOW CONDITIONS THROUGH THE INLET VALVE ALLOWED WATER, SOLIDS, AND PARAFFIN TO DEPOSIT ON THE BOTTOM OF THE VALVE BODY, AND A BACTERIA COLONY FORMED A MICROBIOLOGICALLY INFLUENCED CORROSION PIT. THE CORROSION RATE WITHIN THE PIT INCREASED DUE TO A GALVANIC COUPLE BETWEEN THE IRON SULFIDE DEPOSIT AND IRON MAGNETITE COMPOUNDS, VERIFIED BY LAB ANALYSIS, AND THE STEEL PIPE. THE SITE CONDITIONS WERE FURTHER EXACERBATED BY MICROBIOLOGICALLY INFLUENCED CORROSION WITHIN THE STABLE BIOFILM. THE PARAFFIN ACCUMULATION PREVENTED THE INCOMING OIL TREATED WITH CORROSION MITIGATION CHEMICALS FROM REACHING THE BACTERIA COLONY AND THE IRON SULFIDE AND IRON MAGNETITE DEPOSITS, THEREBY REDUCING THE EFFECTIVENESS OF THE CHEMICALS. IT MUST BE CONCLUDED THAT THIS CORROSION ON THE VALVE BODY WAS NOT RELATED TO THE CHEMICAL TREATMENT OF THE CRUDE OIL OR TO ANY UNEXPECTED CORROSIVENESS OF THE CRUDE OIL. RECORDS SHOW THAT THE CRUDE OIL WAS UNIFORMLY TREATED WITH CORROSION CONTROL CHEMICALS AND BIOCIDES, BUT THE AFTER INCIDENT INSPECTION AND LAB ANALYSIS PROVED THAT THE CORROSION CONTROL CHEMICALS WERE PREVENTED FROM REACHING THE BIOFILM BY A HEAVY LAYER OF WAXY PARAFFIN. ON A GOING FORWARD BASIS, CPL WILL VISUALLY INSPECT TANK INLET VALVES FOR SIGNS OF CORROSION DURING INTERNAL API 653 OUT OF SERVICE TANK INSPECTIONS. CPL WILL ALSO INSPECT ANY VALVES CONSIDERED HIGH-RISK DUE TO PIPING CONFIGURATIONS ON A PERIODIC BASIS USING NON-DESTRUCTIVE TESTING (NDT) METHODS. CPL BELIEVES THE ADDITIONAL VISUAL AND NDT INSPECTIONS OF TANK INLET VALVES WILL MITIGATE THE ROOT CAUSE OF THIS FAILURE IN OTHER LOCATIONS.