Subsea wellhead apparatus
AssigneeDril-Quip, Inc.
InventorsBruce J. Watkins, Larry E. Reimert
Life of this patent
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Abstract
There are disclosed two embodiments of subsea wellhead apparatus each of which includes a subsea wellhead housing installed at the ocean floor, a casing hanger connectable to the to the upper end of a casing string and supported in the bore of the housing to suspend the casing string in the well bore, and a tubing hanger connectable to the upper end of a tubing string and also supported within the housing bore above the casing hanger for suspending the tubing string within the casing string. A primary valve and a secondary backup valve are installed in series for controlling a passageway in the tubing hanger, and during the completion process, with an additional passageway in a Christmas tree which is installed on the head above the tubing hanger.
Claims24
A subsea wellhead, comprising
- a wellhead housing adapted to be installed at the head of a well bore to suspend a casing string therefrom and having a bore therethrough,
- a tubing hanger supported within the bore of the housing to suspend a tubing string within the casing string, and having passageway means connecting the annulus between the casing and tubing strings beneath the tubing hanger with its upper end,
- a first valve including a first valve member in the passageway means,
- means for selectively moving said first valve member between opened and closed position,
- a second valve including a second valve member in the passageway means in series with the first valve member, and
- means for moving said second valve member from a normally open to a closed position independently of operation of the first valve member.
A subsea wellhead, comprising
- a wellhead housing adapted to be installed at the head of a well bore to suspend a casing string therefrom and having a bore therethrough,
- a tubing hanger supported within the bore of the housing to suspend a tubing string within the casing string, and having first passageway means connecting the annulus between the casing and tubing strings beneath the tubing hanger with its upper end,
- a Christmas tree removably mounted on the housing above the upper end of the tubing hanger and having second passageway means forming a continuation of the upper end of the first passageway means,
- a first valve including a first valve member in the first passageway means,
- means for selectively moving said first valve member between opened and closed position,
- a second valve including a second valve member in the first passageway means in series with the first valve member, and
- means for moving said second valve member from a normally open to a closed position independently of operation of the first valve member.
A tubing hanger for use in a subsea wellhead housing having a bore therethrough and a casing hanger supported within the bore of the housing to suspend a casing string therefrom, comprising
- a tubular body having a bore therethrough and adapted to be landed within the bore of the housing to suspend a tubing string connected to its bore within the casing string and having passageway means which, upon landing of the tubular body, connects the annulus between the casing and tubing strings with the upper end of the tubing hanger,
- a first valve including a first valve member installed in the passageway means in the hanger body,
- means for selectively moving the first valve member between opened and closed positions,
- a second valve including a second valve member installed in the passageway means in the hanger body in series with the first valve member, and
- means for moving said second valve member from a normally open to a closed position independently of operation of the first valve member.
A tubing hanger for use in a subsea wellhead housing having a bore therethrough and a casing hanger supported within the bore of the housing to suspend a casing string therefrom, comprising
- a tubular body having a bore therethrough and adapted to be landed within the bore of the housing to suspend a tubing string connected to its bore within the casing string and having first passageway means which, upon landing of the tubular body, connects the annulus between the casing and tubing strings with the upper end of the tubing hanger and thus with second passageway means in a Christmas tree adapted to be removably mounted on the wellhead housing above the tubing hanger,
- a first valve including a first valve member in the first passageway means,
- means thereon for selectively moving the first valve member between opened and closed positions,
- a second valve including a second valve member installed in the first passageway means in series with the first valve member, and
- means for moving said second valve member from a normally open to a closed position independently of operation of the first valve member.
Dependencies are inferred from the claim text.