SOUTHERN STAR CENTRAL GAS PIPELINE, INC

Incident Narrative

ON 10/12/2021 AT 2:27 PM CDT SOUTHERN STAR CENTRAL GAS PIPELINE (SSCGP) RECEIVED NOTICE FROM FIELD OPERATIONS OF GAS BUBBLING TO THE SURFACE IN THE SSCGP WEBB STORAGE FIELD. INITIAL INDICATIONS WERE A LEAK IN THE LATERAL TO WELL #22. IT WAS DECIDED TO CLOSE ALL OF THE LATERALS IN THE STORAGE FIELD AND THESE WERE CLOSED FOR EVALUATION. FOR SAFETY PURPOSES, ALL LATERALS WERE BLOWN DOWN BY 4:48 PM. GAS CONTINUED TO BUBBLE TO THE SURFACE SO THE WELL HEAD VALVES WERE ALL SHUT IN BY 5:28 PM. CLOSURE OF THE WELL HEAD VALVES INDICATED THAT THIS WOULD BE A REPORTABLE INCIDENT. AT 5:48 PM THE NRC WAS NOTIFIED. GAS CONTINUED TO BUBBLE TO SURFACE, ADDITIONAL SSCGP PERSONNEL AND WELL CONTRACTING COMPANIES WERE MOBILIZED TO BEGIN THE METHODICAL PROCESS OF LOGGING ALL OF THE WELLS IN THE STORAGE FIELD. ON 10/19/2021 A SIGNIFICANT ANOMALY WAS DISCOVERED IN WELL #9 AT 1933 FT. ON 10/19/2021, WELL #9 WAS KILLED WITH 15# MUD AND A CEMENT RETAINER WAS PLACED BELOW THE ANOMALY TO ISOLATE THE STORAGE RESERVOIR. A PLUG AND ABANDONMENT PLAN WAS SUBMITTED TO THE OKLAHOMA CORPORATION COMMISSION FOR REVIEW AND APPROVAL. ON 10/23/2021 THE CEMENT RETAINER WAS DRILLED OUT WITH COILED TUBING AND A BRIDGE PLUG WAS INSTALLED NEAR TOTAL DEPTH IN WELL #9 AND THE CASING WAS PARTIALLY FILLED WITH CEMENT AND ANOTHER BRIDGE PLUG WAS INSTALLED ON TOP OF THE CEMENT. ON 10/28/2021 AT 4:30 PM, WEBB STORAGE FIELD EXCEPT FOR WELL #9 WAS RETURNED TO SERVICE. SINCE PLUGGING WELL #9, GAS BUBBLING AT THE SURFACE HAS DECREASED NOTICEABLY. SMALL GAS BUBBLES ATTRIBUTED TO RESIDUAL GAS FROM WELL #9 CONTINUE TO SURFACE AND ARE BEING MONITORED. CONTAINED IN THIS SUPPLEMENTAL REPORT: PART E1A, CORRECTED THE ESTIMATED GAS FLOW IN PIPE AT TIME OF INCIDENT. PART G2, NATURAL FORCE DAMAGE, EARTH MOVEMENT. PLEASE REFER TO THE EXTERNAL FACTORS, CONTRIBUTING FACTORS, CAUSAL FACTORS, AND ROOT CAUSES CONTAINED IN THE KIEFNER REPORT DATED JULY 26, 2022.