Fmc Corporation

Vincent H Vetter

Shiva P Singeetham

Christopher E Cunningham

Michael R Williams

Christopher D Bartlett

William A Valka

Edmund M Mouret

A lightweight ROV deployable tree cap (28) for deployment on a subsea production hub (10) of a subsea tree. A tree cap (28) has a lightweight body (30) with parallel planar sides and including suitable openings and slots for mounting of the various operating elements. A seal plate structure (64) includes a piston (66) connected to a seal plate (68) having a pair of downwardly projecting tubular seal members (70, 72) for fitting within the production bore (13) and annulus bore (15) of the tree hub (10) in a sealed landed position. Fluid pressure is applied to fluid line (96) to urge piston (66) and seal plate (68) downwardly into sealing landed position. For removal or retrieval of tree cap (28) from the installed position on subsea tree hub (10), fluid pressure is applied through fluid lines (108, 110) for the upward movement of seal plate (68) and tubular seal members (70, 72) from sealing relation with production bore (13) and annulus bore (15). Hydraulic fluid is supplied from the ROV through fluid coupling devices (98, 112) which are insertable within receptacles (110,114) in the tree cap body (30). The fluid couplers (98, 112) are removed from the operating receptacles after installation of the tree cap (28) and are parked in other receptacles on A tree frame until needed for further service, such as removal of the tree cap (28). A spare tree cap may be positioned on the tree frame and installed on the tree hub by the ROV.

ROV deployed tree cap for a subsea tree and method of installation

A radially locked subsea housing includes a low pressure housing having upper and lower radial lock regions, each of which regions includes a radial interference surface that is between vertical to only slightly tapered in orientation. A high pressure housing also has upper and lower radial lock regions, each of which regions includes a radial interference surface that is slightly greater in radial diameter than the corresponding interference surface of the low pressure housing. The interference surfaces of the upper and lower radial lock regions form upper and lower interference fits, respectively, between the high pressure and low pressure housings when the housings are assembled subsea. The low pressure housing further includes a landing shoulder defining a landing surface that is substantially more tapered in orientation than are the interference surfaces of the upper and lower radial lock regions, and the high pressure housing includes a landing shoulder defining a landing surface formed to land on the landing surface of the low pressure housing when the housings are assembled subsea. In an alternative embodiment, a zero-clearance, axially extended fit is employed at one or both of the radial lock regions.

Dual radially locked subsea housing

Growing community of inventors

Spring, TX, United States of America

Vincent H Vetter