Completion & workover operations are complex: temporary equipment is deployed to access to a pressurised oil or gas well, changing the well integrity and barrier philosophy. On subsea wells offshore, the completion & workover riser (CWOR) string is normally deployed by a drilling rig, providing a direct conduit from the well to the rig floor.
The CWOR also acts as a backbone for service lines (annulus access, umbilicals), which are strapped to the riser joints and connect to control packages above the rig floor. A the rig moves and heaves, a wear casing is strapped to the outside of the joint running through the rig floor (making it a cased wear joint) protecting the service lines from damage.
Risk management starts long before operations, as risks are identified and mitigated through HAZOP studies, which extensively cover the “what-if” scenarios for every operation.
While the wear casing serves an important purpose, it significantly degrades the reliability of the rig’s diverter function, which would protect rig floor personnel in the event of CWOR or subsea test tree (SSTT) failure – both of which could result in gas release in the marine riser annulus. This is because the seams, gates and voids in the wear casing allow gas to flow through at high rates.
SRP’s sealing wear casing effectively mitigates this risk, by: sealing on the main riser pipe, sealing on each umbilical, service line and annulus line, and providing a smooth outer surface for the diverter to achieve a seal.
The casing construction is steel and there are no loose fixings or fittings that can drop in the well bore. We can supply the casings as individual modules, or a complete cased wear joint.