Riser Based Operations Extended Depth Well Intervention
For extended-depth intervention work, or coiled tubing intervention operations, a rigid riser is needed to connect the subsea tree or wellhead to a well intervention vessel. Riser based intervention uses a high pressure riser to contain the pressure during a workover or intervention operation. Helix Well Ops semisubmersibles Q4000, Q5000 and the monohulls Well Enhancer, Siem Helix 1 and Siem Helix 2 are capable of performing riser-based intervention operations without the increased daily costs and operations time associated with traditional drilling rigs.
Helix utilizes its Intervention Riser System (IRS) to establish a direct connection from the intervention vessel to a subsea tree, with control of the IRS via a multiplex control system (MUX) to the operating vessel. This electronic system reduces control response times to seconds, as opposed to the minutes required for a direct hydraulic control system to travel the length of the umbilical to surface. The IRS system is available with a through bore diameter of 7-3/8” enabling a broad range of well intervention tools to be operated in the subsea well via coil tubing, electricline and slick line services.