Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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4-187 CVE-359
BLOWOUT PREVENTER TESTING APPARATUS
DE~SCRIPTION
BACKGROUND
The present invention relates to an apparatus to be
used in a well structure ~or testing a blowout preventer
under substantial pressures wherein the pressure is exerted
under the closed blowout preventer by sealing across the
upper end of the hanger. With deep wells having a
substantial string suspended from the hanger, the loading
of the hanger landing shoulder on the housing landing seat
is very substantial and the pressure loading above the
hanger increases the landing seat loading well above its
design point so that testing pressures will result in a
failure of the landing shoulder or seat, damage to the
hanger and housing and other future problems in the well.
U. S. Patent No. 2,540,322 discloses the use of a
packing seal on the drill string to allow pressure to be
diverted into the casing above the packing seal for the
testing of the blowout preventer.
U. S. Patent No. 3,~97,824 discloses an annular
~structure mounted on a string which is lowered through a
;20 blowout preventer which seals against the casing, includes
passages extending axially through the skructure and has a
valve plate which is lowered by the string to close the
passages whereby test pressure builds up above the
structure to test the sealing of the blowout preventer.
The testing load of the structure is transferred to the
upper end of the hanger seal assembly.
U. S. Patent NoO 3,093,996 discloses another blowout
preventer tester which is lowered through an open preventer
and seals on the taper of the casing head to deliver
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pressure thereabove for the testing of the closed blowout
preventer.
U. S. Patent No. 4,090,395 discloses a structure which
includes the lowering of a seaL onto the upper end of the
hanger for sealing across the bore of the wellhead and the
string on which it is lowered delivers pressure to the
space above the seal and below the closed blowout prevent-
er. In this structure the pre~;sure load, if not supported
by the string is transferred directly to the hanger landing
shoulder and the wellhead seat on which the hanger landing
shoulder is landed.
None of these prior structures provides the capability
for high pressure blowout preventer testing i. e., 15,000
psi. They do not avoid the imposition of the pressure load
through the hanger landing shoulder to the housing seat.
SUMMARY
The present invention relates to an improved structure
for the pressure testing of a blowout preventer to
relatively high pressures to which it may be exposed in
service and to the sealing structure which is positioned
below the blowout preventer and includes its own support
through which the pressure loading is transferred to the
housing independent of the hangPr loading on the housing
seat. The improved closure structure of the present
invention is used in combination with a wellhead housiny
having an internal landing seat and an internal landing
groove above the landing seat, a casing hanger landed
within the housing with its external landing shoulder on
the internal landing seat of the housing, a blowout
preventer secured in position above the hanger to close
the housing from above and the closure structure includes
a tubular body with a bore therethrough and valving means
for closing such bore and being a suitable size to be
lowered through the blowout preventer and into the housing
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above the casing hanger for landing on the upper portion of the
casing hanger, said closure structure having landing means for
engaging within the internal housing groove and a sliding sleeve
on the exterior of the tubular body adapted to slide within said
landing means for forcing it outward into engagement within said
internal housing groove, a downwardly facing shoulder on the
upper portion of said body positioned to engage said landing means
when it is engaged within said internal housing yroove to transfer
the pressure loading to the housing internal groove, which loading
force results from the testing pressure above such closure
structure within the housing during the testing of the blowout
preventer. It is preEerred that the sleeve be landed on the
upper end of the casing hanger and that the tubular body move
downwardly therein responsive to testing pressure to set said
landing means and transEer the loading force of the pressure
through the landing means to the housing rather than through the
hanger to the housing.
An object of the present invention is to provide an
improved blowout preventer testing structure in which the downward
loading force resulting from the blowout preventer testing
pressure is not transferred through the casing hanger to the
housing internal landing seat.
Another object is to provide an improved closure member
for the testing of a blowout preventer on a wellhead housing which
closure member is responsive to the testing pressure and transfers
the pressure load directly to the housing.
Still another object is to provide an improved closure
structure which can be used within a wellhead housing following
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emergency completion to test the blowout preventer without
overloading the housing landing seat and the hanger landing
shoulder.
In one aspect, the invention provides a wellhead
structure for pressure testing a blowout preventer secured to the
upper portion of a wellhead houslng which has an internal landing
seat and an internal load supporting groove above the landing seat
comprising a hanger having an external landing shoulder landed
within the housing on the internal housing landing seat and having
a hanger body wi-th a bore extending therethrough and an upper rim
extending above the landing shoulder, seal means for sealing
between the exterior of the hanger rim and -the interior of the
housing, a closure member having a tubular body, means for closing
the flow through the interior of the tubular closure member body,
including a back pressure valve secured within the bore through
said closure member body and preventing flow downwardly through
said closure member body bore, a downwardly facing exterior load
shoulder on said closure member body, a split support ring
surrounding said closure member body immediately below said
closure member body load shoulder, a sleeve surrounding said
closure member body and having a surface to coact with said split
support ring so that relative movement of said sleeve within said
split support ring wedges said split support ring into supporting
engagement for said closure member body with said internal housing
groove, and said movement of said sleeve within said split support
ring being responsive to testing pressure between said blowout
preventer and said closure member.
In a further aspect, the invention provldes a wellhead
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structure for pressure testing a blowout preventer secured to the
upper portion o:E a wellhead housing which has an internal landing
sea and an internal load supporting groove above the landing seat
comprising a hanger having an external landing shoulder landed
within -the housing on the internal housing landing seat and having
a hanger body with a bore extending therethrough and an upper rim
extending above the landing shoulder, seal means for sealing
between the exterior o the hanger rim and the interior of the
housing, a closure member having a tubular body, means Eor closing
the ~low through the interior oE the tubular closure member body,
including a cup tester secured within the lower portion of said
bore, a downwardly facing e~terior load shoulder on said closure
member body, a split support ring surrounding said closure member
body immediately below said closure member body load shoulder, a
sleeve surrounding said closure member body and having a surface
to coact with said split support ring so that relative movement oE
said sleeve within said split support ring wedges said split
support ring into supporting engagement for said closure member
body with said internal housing groove, and said movement o~ said
sleeve within said split support ring being responsive to testing
pressure between said blowout preventer and said closure member.
Another aspect of the invention provides, a wellhead
structure for pressure testing a blowout preventer secured to the
upper portion of a wellhead housing which has an internal landing
seat and an internal load supporting groove above the landing seat
comprising a hanger having an external landing shoulder landed
within the housing on the internal housing landing seat and having
a hanger body with a bore extending therethrough and an upper rim
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extendi.ng above the landlng shoulder, sea:L means for sea:Ling
between the exterior of the hanger rim and the interior of the
housing, a closure member having a tubular body, means ~or closing
the Elow through the interior of t:he tubular closure member body,
a downwardly facing exterior load shoulder on said closure member
body, a split support ring surrounding said closure member body
immediately below said closure mernber body load shoulder, a sleeve
surrounding said closure member body and having a surface to coact
with said split support ring so that relative movement o:~ said
sleeve within said split support ring wedges said split support
ring into supporting engagement Eor said closure member body with
said internal housing groove, said sleeve engages the upper end of
said hanger rim and said closure member body moves downwardly
within said hanger bore with said sleeve held against downward
movement by its engagement with said rim whereby said split
support ring is moved downwardly on said sleeve to be wedged
outward into engagement within said internal housing groove, said
movement oE said sleeve within said split support ring being
responsive to testing pressure between said blowout preventer and
said closure member.
An additional aspect oE the invention provides, a
wellhead structure ~or a well comprising a wellhead housing
positioned within a well and having an internal landing seat and
an internal landing suppor-t groove above said landing seat, a
hanger having a tubular body with a bore, an external landing
shoulder engaged on and transmitting hanger loads to said housing
landing seat, and an upper rim above said hanger landing shoulder,
a blowout preventer secured -to the upper end oE said housing, a
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closure member having a bore therethrough, a body with an external
downwardly facing shoulder, a support means positioned around said
closure member body below said downwardly facing closure shoulder
and means responsive to testing pressure between said closure
member and said blowout preventer for wedging said support means
into load transmitting position between said closure member
downwardly facing shoulder and sa:id internal housing groove so
that pressure loads responsive to pressure testing of said blowout
preventer are transmitted to said housing groove by said closure
member shoulder and said support means, and a back pressure valve
mounted within said bore to prevent backward flow therethrough
during pressure testing of said blowout preventer.
A still further aspect of the inven~ion provides~ a
wellhead structure for a well comprising a wellhead positioned
within a well and having an internal landing seat and an internal
landing support groove above said landing seat, a hanger having a
tubular body with a bore, an external landing shoulder engaged on
and transmitting hanger loads to said housing landing seat, and an
upper rim above said hanger landing shoulder, a blowout preventer
secured to the supper end of said housing, a closure member having
a bore therethrough, a body with an external downwardly facing
shoulder, a support means positioned around said closure member
body below said downwardly facing closure shoulder and means
responsive to testing pressure between said closure member and
said blowout preventer for wedging said support means into load
transmitting position between said closure member downwardly
facing shoulder and said internal housing groove so that pressure
loads responsive to pressure testing of said blowout preventer are
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transmitted to said housin~ yroove by said closure mernber shoulder
and sald support means, and a cup tester secured to said closure
member body to prevent downwardly flow therethrough during
pressure testing o~ said blowout preventer.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects, advantages and embodiments of
the present invention are hereinafter set forth and explained with
reEerence to the drawings wherein:
FIGURE 1 is an elevation partially in section which
illustrates the improved wellhead structure with the casing hanger
and closure structure being shown in the lower portion o~ the well
housing (FIGURE lB) and with the blowout preventer being shown
connected to the upper portion of the housing (FIGURE lA).
FIGURE 2 is another view similar to FIGURE lB which
illustrates the improved wellhead structure and the position oE
the closure structure during the pressure testing of the blowout
preventer.
FIGURE 3 is another similar view showing a modiEied
structure which can be used in emergency completions and is shown
in its testing position.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Wellhead housing 10 is positioned within a well bore and
has blowout preventer 12 connected on its upper end. Internal
housing landing seat 14 is provided in the lower portion of
housing 10 as shown and casing hanger 16 which has external
landing shoulder 18 is landed within housing 10 with shoulder 1
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in engagement with seat 14. Groove 20 is positioned within the
lower portion of the interior wall of blowout preventer 12. The
usual seal and lockdown assembly 22 .is positioned in the annular
space 24 between the exterior oE the upper rim 26 oE casing hanger
16 and the interior of wellhead housing 10 above landing seat 14.
Assembly 22 provides the seal across the annular space 24 and
wedges split ring 28 into latching engagement within groove 30 on
the interior of houslng 10 a short distance above landing seat 14.
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Closure member 32 is lowered through blowout preventer
12 into wellhead housing 10 and has its lower end posi-
tioned within the upper interio:r of casing hanger rim 26 as
shown in FIGURE 1. Closure member 32 includes tubular body
34 having internal threaded seat 36 in which back pressure
valve 38 is positioned. ~he lower exterior of tubular body
34 includes external seals 40 for sealing against the
interior of hanger rim 26 and keys 42 which are secured in
axial orientation on the exterior of body 34 above seals
40. Ext~rior surface 44 above keys 42 extends upwardly to
downwardly facing shoulder 46. Surface 48 ends in upper
downwardly facing shoulder 50. Surface 51 above shoulder
has a diameter which is smaller than the .interior
diameter o~ the lower portion of blowout preventer 12 above
and below groove 20. Landing means (split support ring 52)
is positioned around body 34 in surrounding relationship to
surface 48 and in engagement with shoulder 50. Sleeve 54
is positioned around the exterior of body 34 and includes
an upper wedge-shaped end 56 which coacts with tapered
surface 58 on the lower inner surface of split support ring
52 so that movement of sleeve 54 upward under ring 52
causes split support ring 52 to be wedged outwardly into
internal housing groove 20, as shown in FIGURE 2. Sleeve
54 includes internal upwardly facing shoulder 60 and lower
rim 62 which includes slots 64 to receive keys 42. On
landing of closure member 32, the lower end of rim 62 of
sleeve is in engagement with the upper end of hanger rim
26. Spring 66 is positioned on the interior of sleeve 54
and around the exterior of body 34 below shoulder 46 and
around surface 44 above shoulder 60. The spring force is
exerted against sleeve shoulder 60 to urge sleeve 54
downwardly with respect to body 34.
Communications to the interior of housing 10 are
provided by lower ports 6~, intermediate ports 70 and
upper ports 72 through the lower portion of blowout
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preventer housing. Ports 72 would be used to provide a
supply of fluid under pressura for the testing of the
effective s~aling of the rams 74 of blowout preventer 12
as hereinafter explained.
In operation, closure member 32 is lowered throuyh
blowout preventer 12 and into housing 10 to the position
as shown in FIGURE lB. Test:ing of blowout preventer 12
proceeds with the closing of its rams 74 to their position
sealing across the bore 76 through blowout preventer 12.
Thereafter fluid pressure is supplisd through one of the
ports 72 and allowed to build up to the testing pressure.
As this pressure increases it is exerted on closure
member 32 causing it to move downwardly to the position
shown in FIGURE 2. The movement of closure member body 34
is downwardly within the interior of hanger upper rim 26
but sleeve 54 is restrained from downward movement by its
engagement with the upper end of rim 26. This causes
split support ring 52 to move downwardly on the upper end
of sleeve 54 and ring 52 is wedged outwardly into tight
engagement between the lower shoulder of groove 20 and
downwardly facing shoulder 50 on closure body 34 so that
all o~ the pressure load thereafter resulting from the
test pressure above closure member 32 is transferred
through shoulder 50 to ring 52 and to lower shoulder of
groove 20 in blowout prevent~r 12 into housing 10. The
only additional load which is transmitted to hanger 16 is
that spring loading resulting from the relative movement of
sleeve 54 with respect to body 34.
With this configuration the high pressures which are
required for adequate pressure testing of the blowout
preventer on deeper and more recent wells can be accom-
plished without over-loading the landing seat on the well
housing and the casing hanger landing shoulder.
A modified form of the present invention is il-
lustrated in ~IGURE 3 wherein similar parts are given the
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same number designation. Thus, closure member 32 is
landed with its lower end within upper rim 26 of hanger 16
and has a cup tesker 80 threaded into the lower internal
threads in tubular body 34 to complete the closure of the
bore within hanger 16 below the blowout preventer 12.
This would be used in emergency completions with transfer
of the load through the seal assembly 22 to housing 10.
With the apparatus positioned as shown in FIGURE 3,
the closing of the blowout preventer rams 74 and applica-
tion of fluid pressure above closure member 32 will causethe completion of the setting of closure member 32 with
the pressure load being transferred by shoulder 50 to
split support ring 52 onto the lower shoulder of groove
20. In this manner all of the pressure loading is
transferred to housing 10 and does not pass through
hanger 16 to landing seat 14 on the interior of
housing 10.
