Mudline subsea wellhead system
In a subsea wellhead system, an improved means is described for allowing the well to be drilled with a mudline suspension system and completed with a subsea pressure control system, comprising in combination: an outer wellhead housing for location on a subsea floor, having a lower end adapted to be secured to a conductor pipe extending into the well; conductor connector means for releasably securing a string of conductor riser to the outer wellhead housing to extend to the surface; a cement return port extending through the outer wellhead housing; an inner wellhead housing having a lower end adapted to be secured to a string of outer casing, the inner wellhead housing having a bore containing an internal landing shoulder; outer casing connector means for connecting the inner wellhead housing to outer casing riser and for lowering the outer casing riser and inner wellhead housing through the conductor riser with the inner wellhead housing landing in the outer wellhead housing; seal means for sealing the inner wellhead housing to the outer wellhead housing above the cement return port; a first casing hanger having an internal mudline latch profile; intermediate casing connector means; a second casing hanger having an external latch that latches into the internal mudline latch profile in the first casing hanger; inner casing connector means; and the conductor riser, outer casing riser, intermediate casing riser, and inner casing riser allowing the well to be drilled with a mudline suspension system and pressure control equipment at the surface, the inner casing connector means, intermediate casing connector means, outer casing connector means, and conductor connector means being subsequently releasable to remove the inner casing riser, intermediate casing riser, outer casing riser and conductor riser for subsea pressure control completion.
- Assignee:
- ABB VetcoGray Inc., Houston, TX (United States)
- Patent Number(s):
- A; US 5240081
- Application Number:
- PPN: US 7-941479
- OSTI ID:
- 6092376
- Country of Publication:
- United States
- Language:
- English
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