A large multinational exploration and production company with a long-established presence in Tunisia had an urgent requirement for a valve sealant to regain well integrity.
The Operator had a serious incident on a high-pressure gas and condensate well. The wing valve on a 4-1/6” 10K Xmas Tree had a hole cut through the valve body on the upstream side due to erosion from produced sand, resulting in a uncontrolled hydrocarbon leak.
The Emergency Shut Down (ESD) was functioned closing the Hydraulic Master Valve (HMV), but this valve was leaking in the closed position. The two manual master valves were then closed and also failed to provide a full leak tight isolation, leaving the well in a dangerous state.
Repeated attempts were made over subsequent days to regain well integrity. Different valve lubricants were injected into the Master Valves by both the OEM and Independent Service Teams, but all efforts made were unable to successfully pressure test any of the valves and the leak continued.
Our Valve Sealant 701 was pumped into the lower and middle master valves (manual valves). Immediately after injection of 701, the tubing head pressure of 3150 psi was bled off to zero on the downstream side of the master valves. With the well shut-in, The field service team left overnight and then ran pressure tests again the following morning, confirming a zero leak rate.
The Operator and Service Teams successfully regained well integrity, enabling the well to be shut-in safely. The failed wing valve was isolated fully with multiple upstream barriers, permitting a safe valve replacement job and enabling the well to be swiftly brought back onto production.