The platform was located on a Large Gas Producing Field in the Central North Sea.
The Wells were beginning to water out and in an attempt to increase production the decision was made to run Coil Tubing Velocity Strings.
During the first string installation a runaway occurred which resulted in the shear seals being closed on the coil to secure the Well.
The platform has a drilling rig installed which at the time was in tepid stack. A cost and risk analysis identified Hydraulic Work Over as the most efficient way to regain Well integrity.
The objective was two parts: Firstly, to regain the use of the tree by clearing the coil across the tree. Secondly, to clear the coil to below the safety valve and regain use of the safety valve.