Solution & Implementation
Furmanite was called in to partner Shell and Halliburton in rectifying the situation. The operation on each actuator was extensive and included isolating the valve, removing the outer can and spring retainer, removing the spring guide, removing and replacing the spring, redressing the actuator and finally, function and pressure testing the actuator. The actuators on four of the wellheads had seized due to the stresses of natural environmental forces, and so Furmanite’s machining expertise was called upon. In order that a complete repair of the actuator could be undertaken the outer actuator cylinder had to be split using a specialist machine. Furthermore, technicians had to machine the end caps of the inner sleeve of the spring retainer (12-inches in outside diameter and 24-inches long), which had seized to the valve bonnet creating a further barrier to work being carried out. A rigorous planning exercise was undertaken with full contingency planning and comprehensive on-shore trials of equipment and techniques. It was planned that the work undertaken by Furmanite would last 17 days, in reality it took technicians only seven days to complete the isolated repair.