Pull-up Metal Seal System for Subsea Wellhead Equipment

摘要

This paper presents the design of a new pull-up metal-to-metal sealsuitable for use in subsea wellheads. The development of such sealsinvolves careful consideration of the environmental and operationalrequirements for subsea wellheads. The environments in which sealingsystems working on must operate are necessarily harsh. This designinvolves special structure differed from earlier types. It’s actuated bypull-up force which obtained from drill pipe. For deep water or evenultra-deep water drilling, as we all know, the whole drill string is justsoft as a rope, so its elasticity is much better than compressibility,which means the pull-up force can actuate seal safely and effectively.More importantly, the unique design of wedge-shaped structure candraw back into the casing hanger, before the seal being actuated, and itcan also avoid scoring damage on the seal surface during installation,because of its small diameter. A finite element analysis being used todetermine wellhead seal parameters and its performance for subseadrilling service is also presented.