Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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1 This application is a divisional of application
serial number 350,171 filed April 18, 1980.
The present invention relates to sealing members for ram
blowout preventers.
Prior art pipe shearing rams for shearing drill
strings or drill pipe are shown, for example, in U.S.
Patents Nos. 2,919,111; 2,969,838; 3,561,526; 3,590,920; and
3,766,978. However, there has been some concern as to whether
cut ends of pipe or debris resulting from shearing would hamper
sealing action in these shearing rams.
U.S. Patents Nos. 3,736,982; 3,817,326 and 3,946,806
have utilized a sealing element disposed on one of two shearing
rams in the shearing plane to seal between the two rams when
closed. In addition to shearing and sealing operations, it is
often necessary to use these rams as "blind" rams in order to
seal the bore without shearing any pipe. Concern has been
expressed that the sealing element between the rams might
extrude beyond the ram surface after several "blind" closures.
Should a need to shear drill pipe then arise, the sealing element
~ would be exposed to damage by the sheared drill pipe. Further,
the sealing element between the blades was energized by lateral
~ovement of elastomer. Due to frictional forces, sealing
pressure on the elastomer towards the center of the sealing
element was reduced from that at the outer portions.
In the structure of U.S. Patent No. 3,736,982, a
lateral sealing element between the two shearing ram surfaces
was energized when a ram block of an upper ram of the two
rams was contacted by the lower ram. However, if drill pipe
contacted the ram block during shearing, energization of the
seals occurred. Thus, the lateral sealing element could be
moved into a position where it was subject to damage by the
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sheared drill pipe. Additionally, the lateral sealing element
was limited in size to a small lateral reservoir slot in one ram,
and if damage by the sheared pipe was large, insufficient elasto-
mer might be present in the reservoir to effec-t a seal between
the two rams.
Briefl~, the present invention provides new and improved
sealing members ~or mounting behind a shear blade in a blowout
preventer. The blowout preventer has rams for shearing drill
or well pipe and for sealing the bore. The rams may also be used
as blind rams for sealing the bore in the absence of objects in
the bore.
The sealing ram is used to seal the bore in conjunction
with another ram and includes a carrier block for moving a
shearing blade to and from the bore and a sealing member having
a lower sealing portion which moves downward to seal with the
other ram. An upper forcing portion of the sealing member
responds to movement between the two rams to force the lower
sealing portion downwardly. The two portions of the sealing
member are spaced from each other b~ a transverse separation slot
which forms planar contact surfaces between these portions of the -
sealing member. The separation slot permits transverse flow of
the material of the forcing member in response to relative move-
ment between the rams to be transferred into downward flow of the
material of the sealing portion of the sealing member.
The rams provide new and improved structure for
mounting the shear blade to the carrier block to resist forces
imposed during shearing which might misalign or damage the shear
blade and impair the effectiveness of shearing.
Fig. 1 (located on page with Figs. 6, 6A, 7 and 8)
is a vertical sectional view of a blowout preventer with shearing
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and sealing rams according to the present invention;
Fig. 2 is a partial plan view of the ram-s of Fig. 1
in position for shearing an object;
Fig. 3 is a cross-sectional view of the rams of Fig. 2;
Fig. 4 is a partial plan view of the rams of Fig. 1 in
position for sealing a well bore subsequent to shearing an
object;
Fig. 5 is a cross-sectional view of the rams of Fig. ~;
Fig. 6 is a cross-sectional view of one of the shearing
and sealing rams of Fig. 1;
Fig. 6A is a front elevation view of the ram of Fig. 6;
Fig. 7 is a schematic diagram of elastomer flow in
forming a seal in rams according to the present invention; and
Fig. 8 is a cross-sectional view of portions of the rams
of Fig. 6.
In the drawings, the letter B (Fig. 1) designates
~generally a blowout preventer according to the present invention.
The blowout preventer B has a bore 10 formed through a body
member 12 thereof, for passage of a well object T, which may be
~0 well tubing, well tools or other like objects, therethrough in
the known manner for well operations. The blowout preventer B
is constructed so -that it is positioned in a stack of blowout
preventers or in a string of well casing or pipe in any suitable
manner, as will be well understood by those skilled in the art.
As will be set forth below, the blowout preventer B of the present
invention permits the bore 10 of the well to be sealed without
requiring that the object T be removed therefrom, by shearing
the object T and thereafter sealing the well bore across the
surfaces along which shearing of the object T takes place.
The blowout preventer B includes a shearing and sealing
ram S, which in conjunction a shearing ram R shears the object T
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in the bore 10. As will be set forth below, sealiny structure
on the ram S thereafter seals the bore 10 between the rams R and
S against well pressures. The ram S and ram R are also adapted
to seal the bore 10 without shearing when there is no object
present therein.
The ram S is mounted in a recess 14 formed in a bonnet
16 mounted with the body member 12. The recess 14 is aligned
with an opening 18 in the body member 12 transverse to the bore
10 so that the ram S may move transversely into the bore 10 to
shear the ob~ect T in conjunction with the ram R.
Similarly, the ram R is mounted in a recess 20 formed
in a bonnet 22 mounted with the body member 12 on an opposite
side thereof from the bonnet 16. The recess 20 is aligned with
an opening 24 in the body member 12 transverse to the bore 10 and
in align~ent with the recess 14 and opening 18 so that the ram R
may move transversely into the bore 10 and shear the ob~ect T
in conjunction with the ram S. i
The ram S and the ram R are each moun-ted at an inner
end 26 of a ram piston shaft 28 of a ram carrier piston 30. The
ram carrier pistons 30 are each mounted within a support sleeve
32 within a ram cylinder 34. The ram cylinders 34 each receive
operating fluid pressure therein through conventional fluid con-
duits, either integxally formed in the body member 12 or as
separate ~luid conduits with ported inlets into the cylinders 34.
Closing ope~a~ing fluid pressure is introduced into the cylinder
34 to act on a rear face 30a of each ram carrier piston 30 to
move the ram S and the ram R inwardly into the bore 10 to shear
the object T and thereafter seal the bore 10. Opening operating
fluid pressure is introduced into the cylinder 34 to act on a
front face 30b of each ram carrier piston 30 to move the ram S
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1 and ram R outwardly from the bore 10 to open the bore 10 when it
becomes desirable to do so. Suitable seals are provided in the
cylinders 34, such as with the ram carrier piston 30 to prevent
leakage of operating fluid pressure between the faces 30a and 30b
of the piston 30, and other fluid leakage, as will be understood
by those skilled in the art.
Each of the ram carrier pistons 30 had a piston tail
shaft 36 extending outwardly therefrom into an opening 38 of an
end cylinder 39 mounted with the ram cylinder 34. The piston tail
shafts 36 move inwardly and outwardly with respect to the openings
38 of the cylinders 39 during movement of the ram S and the
ram R in the blowout preventer B. The blowout preventer B may also
be provided with suitable automatic or manual ram locks, as will
be understood by those skilled in the art, which are, however,
not shown in the drawings to preserve clarity therein.
Considering the rams R and S, SUC}I rams are shown in a
half or partial plan view in Figs. 3 and 5, it being understood
that other portions of such-ram are of like construction to the
portions shown. The ram R includes a carrier block 40 (Fig. 3)
with a rear socket 41 for receiving a button formed at the inner
end 26 of ram piston shaft 28. The carrier block 40 has a lower
shearing blade member 42 mounted therewith on a lower inner face
portion 44 by means of fastener screws 46 or other suitable attach-
ing means, The lower blade member 42 is adapted to shear the
object T in conjunction with a blade-on the ram S to be set
forth.
A clearance pocket or space 48 is formed in the carrier
block 40 above the inner portion 44 to receive a stub 50 or cut
upper end of the object T. A threaded socket may be formed
in an upper surface 54 of the block 40 to receive a connector
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1 screw so that the ram R may be removed from the blo~out preventer
B for service, repairs or the like.
An annular sealing pocket 56 is formed in the upper
surface 54 of the block 40 to receive a generally horseshoe-shaped
sealing member 58 formed of a suitable sealing elastomer
material. The sealing member 58 forms a seal about the upper
periphery of the ram R with the body member 12. Enlarged head
or front seal portions 60 of the sealing member 58 are formed in
front pockets 62 in inner portions on each side the block 40 to
engage similar structure on the ram S, to be set forth, and form
vertical seals between the ram R and S in the bore 10.
Contact faces 64 are formed on inner front face portions
of the block 40 adjacent seal portions 60 to engage sealing
structure on the ram S during relative movement between the rams R
and S after shearing of the object T in order to assist in
forming a transverse seal, in a manner to be set forth, across
the bore 10 between the rams R and S in the plane where shearing
of the object T has occurred.
Considering the ram S more in detail (Fig. 3), a carrier
~0 block 70 has a socket 71 formed therewith for connection with a
button formed at the lnner end 26 of the ram piston shaft 28.
A lower clearance pocket or space 72 is formed in the carrier
block 70 to receive a stu~ or lower cut end 73 of the object T
(Fig. 5). An annular sealing pocket 74 is formed in the carrier
block 40 at anlupper surface 76 for receiving a suitable sealing
elastomer 78, of a generally horseshoe-shaped configuration,
typically synthetic rubber, to form a seal between the upper
periphery of the ram S and the body member 12 about the periphery
of the bore 10.
Enlarged head or front portions 80 are formed on the
sealing member 78 of a suitable sealing elastomer in front
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1 pockets 82 in the block 70 to engage the head portions 60 in
the sealing member 58 of the ram R to form vertical seals along
the bore 10 between the rams S and R. Vertically extending
protuberant ribs 86 are preferably formed on front faces of the
front portions 60 and 80 to insure elastomer flow to affect a
firm seal with the body 12 by sealing members 58 and 78. Also,
typically stiffener members of a suitable configuration, such as
those shown in phantom at 88 (Fig. 6) are formed in the seal
members 58 and 78 in the head portions 60 and 80, respectively,
by being bonded therein for increased strength of such seal
members.
The ram S further may also include a threaded socket
formed in the upper surface 76 of the block 70 to receive a
suitable connector screw or the like so that the ram S may be
removed from the blowout preventer B for service, repairs or
the like.
The ram S further includes an upper shearing blade 92
mounted on an inner portion of the block 70 on an upper face
portion 96 by means of fastener screws 97 or other suitable
attaching means. The upper shear blade 92 has a rearwardly ex-
tending tongue member 98 formed therewith which is adapted to
fit within a transversely extending slot 100 ~Fig. 6) formed in
the upper face portion of the block 70. A plurality of downwardly
extending threaded openings 102 are formed in the upper surface
76 of the carrier block 70 and extended downwardly so that set
screws 104 may be inserted therein to engage the tongue member
98 of the shear blade 94 (Fig. 3). The mounting arrangement
between the tongue member 98, the slot 100 and the screw 104
provides an important function. During shearing operations, it
is very important that the spacing between the shear blades 92
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1 and 42 of the rams S and R, respectively, be maintained within
an acceptable tolerance in order to assure proper shearing action.
Should the spacing between the two blade members become excessively
large, the object T would become very resistant to shearing
forces, and the rams S and R might not be able to exert sufficient
shearing forces to shear such an ob~ect. By means of the set
screws 104l the mounting of the blade member 92 on the ram S may
be adjusted so that the spacing between the blade members 92
and ~2 can be established at the desired spacing required for
1~ proper shearing between the rams S and R. Further, the rearwardly
extending tongue member 98 of the shear blade 92 provides an
- additional function, namely providing strength for the blade
member 92 in order to resist any bending or twisting movement
exerted thereon by the upper portion of the o~ject T during
shearing operations.
A lateral seal member 110 is mounted in the ram S
between the carrier block 70 and the shear blade 92 acro$s the
width of the ram S and lS adapted to be moved into engagement
with an upper surface 112 of the ram R to form a secll -
2~0 transversely between the ram S and R across the bore 13. The
seal member 110 in conjunction with seal members 58 and 78 thus
seals the bore 10 against well pressures.
The seal member 110 is formed from a suitable elasto-
meric material and includes a lowe~ sealing member 116 which is
mounted at a rlecessed position from the surface 114 during
shearing operations and thereafter moves downwardly into
contact therewith to form the seal between the rams S and R
transversely across the ~ore 10. The seal 110 further includes
an upper forcing portion 118 which is spaced from the lower
sealing portion 116 by a trans~erse separation slot 120
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1 (Figs. 6 and 7), for reasons to be set forth. It is to be
noted that the seal member 110 is at a recessed position within
the ram S during shearing operations to reduce the risk of damage
or scoring by cut ends oE the object T or other debris.
The seal member 110 further includes side contact pads
122 which extend outwardly Erom the carrier block 70 ad~acent
side portions 124 of the shear blade 92. The contact pads 124
are adapted to be engaged by the contact faces 64 of the ram R
after the object T has been sheared, so that relative movement
between the rams S and R can be used to cause movement of the
material of seals 58 and 78 to seal with the body 12 of the
blowout preventer B and also downward movement of the portion 116
of the seal member 110 to form the seal between the rams S and
R.
A stiffener member 126 is bonded within the contact
pads 124 adjacent an upper end thereof to prevent upward
extrusion of the elastomer material of the contact pads 124
when engaged by the contact faces 64.
A plurality of stiffener pins 127 are mounted within
the contact pads 124 to provide structural support for the seal
member 110, with a rear portion extending rearwardly therefrom
for insertion into matching sockets formed in the front face
of the carrier block 70 in order to support the seal member 110
in position between the carrier block 70 and the shear blade 92.
The sealing portion 116 and the forcing portion 118 are inte-
grally connected with the contact pads 124 so that the sealing
member is a unitary elastomeric member with the slot 120 formed
therein. Accordingly, forces exerted on the contact pads 124
are transmitted into the other portions of the sealing member
110-
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1 The contact pads 124 extend outwardly from the carrier
block 70 a suitable distance in the unengaged position (Fig. 2),
providing a surface for contact with the contact faces 64.
Upon such contact, fuxther relative movement between the rams S
and R begins displacement of elastomer from the contact pads 124
into the portions 116 and 118.
The upper portion 118 of the seal member 110 tapers
inwardly from the contact pad 124 ln order to channel the flow
of elastomer in the upper portion 118 of the seal member 110 as
indicated schematically in Fig. 7. The tapering of portion 118
begins at a first substantial tapering along a por-tion 130
thereof and second more gradual tapering along a portion 132
thereof to a mid-point 134. Suitable surfaces 136 and 138 are
formed on the carrier block 70 and similarly on the rear surface
of the shear blade 92 to ensure confinement of the elastomer
material of the seal member 110 within these tapering portions.
If desired, a suitable transverse stiffener member may
be mounted in the sealing portion 116 of the seal member 110, as
shown at 140 in the drawings, to prevent extrusion of the
material thereof by means of pressure within the well bore 10
after sealing has been effected between the rams S and R.
During the operation of the present invention, the
ob~ect T is sheared by the shear blades 42 and 92 in response
to fluid pressure on the pistons 30. In the event that the
bore 10 is to be sealed in the absence of an object therein
and the rams R and S are thus to serve as "blind" rams, such
rams are moved relative to each other by fluid pressure. Initial
contact is made between the ribs 86 of the ram R and the ram S.
Thereafter, contact is made between the head or front portions
80 and 60 of such rams, forming vertical seal along the bore 10
between the rams S and R. Upon further relative movement between
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1 the rams R and S, elastomer displacement will occur in the
elastomer material of the sealing members 58 and 78, forming a
seal between the upper faces of the rams S and R with the body 12
of the blowout preventer B.
Shortly thereafter, the contact faces 64 of the ram R
engage the contact aces 124 of the elastomer material of the
seal 110 at each end thereof. Further movement of the ram R
with respect to the ram S displaces the elastomer material of the
contact faces 124 downwardly and laterally across the upper
forcing member 118 of the seal member 110. Due to the presence
of the transverse slot 120 between the upper portion 118 and
the lower sealing portion 116 oE the seal member 110, displacement
of the elastomer from the contact pad 124 occurs in a transverse
direction (as is seen in Fig. 7) in the upper portion 118. How-
ever, the presence of the transverse slot permits the formation
of contact planes between the upper forcing portion 118 and the
lower sealing portion 116 so that displacement of elastomer
transversely in the upper forcing member 118 i~ transferred
according to the present invention into substantially downward
displacement of the sealing member 116 forcing the sealing member
116 from a recessed position within the ram S downwardly to
engage the surface 114 of the ram R, formin~ a transverse seal
between the ram S and the ram R across the bore lO of the blowout
preventer B.
Displacement of the seal llO in response to movement
between the ram R and S continues until metal engagement is
formed between the contact face 64 of the ram R and a metal
contact surface 142 ~Fig.5 ~ in the ram S, thereby preventing
further relative movement between the rams R and S. However,
adequate elastomer displacement has occurred into the inner
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1 portion of the seal 110 and into the upper seals 58 and 78 to
compensate ~or any seal damage which may have previously occurred
by feeding reserve elastomer in-to the damaged areas.
The foregoing description and disclosure of the present
invention is illustrative and explanatory thereof and various
changes in the size, shape and material, as well as in the
illustrated construction of the preferred embodiment may be made
without departing from the spirit of the invention.
.
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