Umbilical design and installation for Mustique and Shasta tie-backs
The design and installation of control umbilicals for the Mustique and Shasta subsea satellite well tiebacks are reviewed with respect to how cost-effective umbilical termination assembly (UTA) designs can be achieved while also providing full control system sparing and good installation flexibility. The sparing philosophy of the electrohydraulic control system as a whole from the platform to the tree control pods is discussed. This approach led to the selection of a bottom connection method for the umbilicals by atmospheric diving system (ADS) and thus made possible the use of a lay vessel which could be scheduled independently of the well completion and tree installation operations. The benefits and risks of requiring spliceless umbilicals are discussed as well as their impact on manufacturing deliveries and installation schedules. The Mustique/Shasta umbilicals were an industry first with a single contractor responsible for the system planning, design, manufacture, installation, subsea connection and on-production performance guarantees. A key ingredient of this concept is the design of umbilical termination assemblies (UTAs) and ROV maintainable interconnections. This contracting approach offers significant benefits to the customer. The benefit of the sparing approach taken is illustrated by describing how two subsea failures were remedied without incurring operational downtime.
- OSTI ID:
- 434065
- Report Number(s):
- CONF-960525--
- Country of Publication:
- United States
- Language:
- English
Similar Records
New features on ROVs and control systems add flexibility and cut costs
Tahoe subsea completion -- A successful application of existing and new technologies