TRUNKLINE GAS CO

Incident Narrative

THIS PIPELINE LEAK WAS REPORTED TO TGC GAS CONTROL CENTER AT 1506 HRS. BY A LOCAL OILFIELD OPERATOR WORKING FOR AN UNIDENTIFIED PRODUCER IN THE AREA. THIS OPERATOR WAS WORKING FROM A FLOAT PLANE AND FLEW OVER THE LEAK LOCATION. GAS CONTROL CONTACTED THE LOCAL OPERATIONS PERSONNEL WHO DISPATCHED A HELICOPTER TO THE LOCATION TO VERIFY THE REPORT. UPON ARRIVAL THE LOCAL PERSONNEL CONFIRMED THE LEAK AND WAS ABLE TO LAND NEAR THE DOWNSTREAM VALVE SETTING AND CLOSE THE ISOLATION VALVE. ONCE ADDITIONAL PERSONNEL ARRIVED ON LOCATION THE HELICOPTER WAS DISPATCHED OFFSHORE TO VR 26B AND THE UPSTREAM ISOLATION VALVE CLOSED AND THE PIPELINE WAS SHUT IN AT 1701 HRS. AND PRESSURIZATION PROCESS COMMENCED. DURING THE DEPRESSURIZATION PROCESS THE PIPELINE BEGAN TO LEAK CONDENSATE. TGC PERSONNEL IMMEDIATELY DISPATCHED AN LOCAL OSRO TO THE LOCATION TO ISOLATE THE RELEASE AND BEGIN CLEAN-UP OPERATIONS. ONCE THE RELEASE WAS CONTAINED PIPELINE REPAIR RESOURCES WERE MOBILIZED AND AN ATTEMPT WAS MADE TO EXCAVATE THE PIPELINE. BECAUSE OF THE DEPTH OF THE PIPE AND THE UNSTABLE SOIL CONDITIONS THE DECISION WAS MADE TO BRING IN A GEOTECHNICAL ENGINEERING CONTRACTOR TO PERFORM SOIL ANALYSIS AND PROVIDE AN EXCAVATION SHORING SYSTEM TO MEET OSHA REGULATIONS. THE INVESTIGATION AND REPAIR OPERATION ARE ON HOLD UNTIL THE SHORING SYSTEM IS AVAILABLE AND CAN BE INSTALLED TO ALLOW SAFE ENTRANCE INTO THE EXCAVATION. THIS LINE WAS ABANDONED FOLLOWING THE INVESTIGATION INTO REPAIRING THE PIPELINE. THE COST AND DIFFICULTY OF REPAIR WERE THE ATTRIBUTING FACTORS FOR THE DECISION.