U.S. patent application number 10/210825 was filed with the patent office on 2004-02-05 for compact insert for variable bore ram packer in a ram type blowout preventer.
This patent application is currently assigned to Cooper Cameron Corporation. Invention is credited to Foster, Anthony P., Gaudette, Sean L..
Application Number | 20040021269 10/210825 |
Document ID | / |
Family ID | 31187436 |
Filed Date | 2004-02-05 |
United States Patent
Application |
20040021269 |
Kind Code |
A1 |
Gaudette, Sean L. ; et
al. |
February 5, 2004 |
Compact insert for variable bore ram packer in a ram type blowout
preventer
Abstract
A variable bore ram packer designed for use in a standard
ram-type blowout preventer used in oil and gas drilling operations
is disclosed. The variable bore ram packer is molded of an
elastomeric material having a central semi-circular opening sized
to fit closely about a tubular member. The packer member includes a
plurality of pillar inserts molded within the elastomeric material
around the central semi-circular opening. The packer member and the
plurality of pillar inserts are molded into a unitary structure
allowing the plurality of pillar inserts to move and seat against
different diameter tubular members to prevent extrusion of the
elastomeric material between the pillar inserts and the tubular
member. The pillar inserts include a top plate, a bottom plate and
a reduced cross section central column integrally formed
therebetween. The reduced cross section central column allows a
rubber with higher moduli to be used.
Inventors: |
Gaudette, Sean L.; (Katy,
TX) ; Foster, Anthony P.; (Houston, TX) |
Correspondence
Address: |
Michael P. Hartmann
Cooper Cameron Corporation
P.O. Box 1212
Houston
TX
77251-1212
US
|
Assignee: |
Cooper Cameron Corporation
|
Family ID: |
31187436 |
Appl. No.: |
10/210825 |
Filed: |
August 1, 2002 |
Current U.S.
Class: |
277/325 |
Current CPC
Class: |
E21B 33/062
20130101 |
Class at
Publication: |
277/325 |
International
Class: |
E21B 033/06 |
Claims
What is claimed is:
1. A variable bore packer used in a ram-type blowout preventer for
oil and gas drilling operations, comprising: a packer member molded
of elastomeric material having a central semi-circular opening
sized to fit closely about a tubular member; a plurality of pillar
inserts molded within said elastomeric material around said central
semi-circular opening to form an insert array; said packer member
and said insert array being molded into a unitary structure
allowing said insert array to move and seat against different
diameter tubular members to prevent extrusion of said elastomeric
material between said pillar inserts and the tubular member; said
unitary structure is molded to form a pair of side packers integral
with said packer member; said pillar inserts include a top plate, a
bottom plate and a central column positioned therebetween; and,
said central column is sized to allow a substantial reduction in
the stiffness of the packer member and insert array when said
elastomeric material is a higher modulus rubber.
2. A variable bore packer used in a ram-type blowout preventer for
oil and gas drilling operations according to claim 1, wherein: said
central column has a rectangular cross section.
3. A variable bore packer used in a ram-type blowout preventer for
oil and gas drilling operations according to claim 2, wherein: said
top plate, said bottom plate and said central column are integrally
formed.
4. A variable bore packer used in a ram-type blowout preventer for
oil and gas drilling operations according to claim 3, wherein: each
of said top and bottom plates includes a guide lip and a guide
shoulder; and, said plurality of pillar inserts coact to provide an
irising motion to move and seat against different diameter tubular
members.
5. A variable bore packer used in a ram-type blowout preventer for
oil and gas drilling operations according to claim 4, including: a
plurality of packer pins molded in said packer member to connect
said variable bore packer to a ram-type blowout preventer.
6. A ram-type blowout preventer used in oil and gas drilling
operations having a variable bore ram assembly, comprising: a body
with a vertical bore; a pair of opposing bonnet assemblies
laterally disposed in said body; a pair of opposing variable bore
rams laterally moveable within said bonnet assemblies; said
variable bore rams providing a seal around a tubular member having
a diameter within a predetermined range, said tubular member
disposed within said vertical bore upon closing of said variable
bore rams; said pair of variable bore rams each includes a ram
body, a top seal and a packer member; said packer member molded of
elastomeric material having a central semi-circular opening sized
to fit closely about a tubular member; said packer member includes
a plurality of pillar inserts molded within said elastomeric
material around said central semi-circular opening to form an
insert array; said packer member and said plurality of pillar
inserts being molded into a unitary structure allowing said insert
array to move and seat against different diameter tubular members
to prevent extrusion of said elastomeric material between said
pillar inserts and the tubular member; said unitary structure is
molded to form a pair of side packer seals integral with said
packer member; said pillar inserts include a top plate, a bottom
plate and a central column positioned therebetween; and, said
central column is sized to allow a substantial reduction in the
stiffness of the packer member and insert array when said
elastomeric material is a higher modulus rubber.
7. A ram-type blowout preventer used in oil and gas drilling
operations having a variable bore ram assembly according to claim
6, wherein: said central column has a rectangular cross
section.
8. A ram-type blowout preventer used in oil and gas drilling
operations having a variable bore ram assembly according to claim
7, wherein: said top plate, said bottom plate and said central
column are integrally formed.
9. A ram-type blowout preventer used in oil and gas drilling
operations having a variable bore ram assembly according to claim
8, wherein: each of said top and bottom plates includes a guide lip
and a guide shoulder; and, said plurality of pillar inserts coact
to provide an irising motion to move and seat against different
diameter tubular members.
10. A ram-type blowout preventer used in oil and gas drilling
operations having a variable bore ram assembly according to claim
9, including: a plurality of packer pins molded in said packer
member to connect said variable bore packer to a ram-type blowout
preventer.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to an improvement in variable bore
ram packers for a ram-type blowout preventer used in oil and gas
drilling operations. The improved ram packer is designed to reduce
the overall stiffness of the packer, thereby allowing it to be more
elastic and to better seal on the contours of the drill pipe
disposed within the bore of the blowout preventer. This
configuration allows the use of rubber having higher moduli which
is desirable in high temperature well conditions. Ram-type blowout
preventers are part of a pressure control system used in oil and
gas drilling operations to control unexpected well bore pressure
spikes or "kicks" as they are commonly referred to in the
industry.
[0003] The blowout preventer has a body with a vertical bore and a
pair of laterally disposed opposing bonnet assemblies. Each bonnet
assembly includes a piston which is laterally moveable within the
bonnet assembly by pressurized hydraulic fluid. Replaceable sealing
elements called "packers" are mounted within rams attached to the
ends of the pistons which extend into the blowout preventer bore.
When these pistons are moved to a closed position, commonly
referred to as "closing the blowout preventer" or "closing the
rams", the vertical bore of the blowout preventer is sealed and the
kick is contained. These packers are available in a variety of
configurations designed to seal the blowout preventer bore when the
opposing rams and pistons are moved to their closed position.
[0004] One type of ram with packer has ends designed to seal around
pipe of a specific size in the blowout preventer bore when the
blowout preventer is closed. Other rams with packers are configured
to seal around a range of pipe sizes. It is the type designed to
seal around a range of pipe sizes, called variable bore ram packers
to which the present invention is directed. The ram packers form a
pressure tight seal during a kick until the well bore pressure can
be controlled. The well bore pressure can reach several thousand
pounds per square inch during a kick. Each ram packer has a
semicircular opening in its front face to form a seal around
180.degree. of the outer periphery of the pipe. When the rams are
closed as described above, the opposing ram packers meet and seal
the entire 360.degree. periphery of the pipe. The novel variable
bore ram packer of the present invention is designed to reduce the
stress in the rubber by utilizing a reduced cross section metal
insert.
[0005] In an effort to minimize the tearing and loss of mass of the
elastomeric sealing element, numerous modifications and additions
to the ram packer and particularly the elastomeric sealing element
in ram-type blowout preventers have been used. The variable bore
ram packer of the current invention offers a substantial
improvement by offering a variable bore ram packer with increased
elasticity which improves the service life of the packer and
reduces the forces needed to operate the variable bore packer.
[0006] 2. Description of Related Art
[0007] The use of metal inserts in a conical-type blowout preventer
is disclosed in U.S. Pat. No. 2,846,178 to B. S. Minor.
[0008] U.S. Pat. No. 3,897,038 to R. K. Le Rouax shows a ram type
blowout preventer using metal inserts as an anti-extrusion
means.
[0009] The use of metal inserts in an annular blowout preventer to
control the stress level in the elastomeric packer unit is shown in
U.S. Pat. No. 3,917,293 to G. E. Lewis et al.
[0010] U.S. Pat. No. 4,099,699 to H. Allen shows the use of irising
metal inserts in an annular blowout preventer.
[0011] Another example of metal inserts in a variable bore blowout
preventer in disclosed in U.S. Pat. No. 4,229,012 to B. C.
Williams, III.
[0012] U.S. Pat. No. 4,444,404 to G. C. Parks, Jr. shows an example
of a variable bore ram packer with interlocking anti-extrusion
metal inserts.
[0013] Another example of a variable bore ram packer with
interlocking anti-extrusion metal inserts is disclosed in U.S. Pat.
No. 4,458,876 to G. R. Schaeper et al.
[0014] U.S. Pat. No. 4,550,895 to D. U. Shaffer shows an early
version of a variable bore ram packer. This apparatus utilizes a
plurality of annular segments embedded in the elastomeric rubber to
aid in effectuating a seal.
SUMMARY OF THE INVENTION
[0015] The variable bore ram packer of the present invention is
designed for use in a standard ram-type blowout preventer used in
oil and gas drilling operations. The blowout preventer has a body
with an axial bore, a pair of opposing bonnet assemblies and a pair
of opposing rams laterally moveable within the bonnet assemblies by
a pressurized fluid source to control flow of well fluids through
the blowout preventer body axial bore. The variable bore ram packer
includes a ram body, a top seal and a packer member. The packer
member is molded of an elastomeric material having a central
semi-circular opening sized to fit closely about a tubular member.
The packer member includes a plurality of pillar inserts molded
within the elastomeric material around the central semicircular
opening. The packer member and the plurality of pillar inserts are
molded into a unitary structure allowing the plurality of pillar
inserts to move and seat against different diameter tubular members
to prevent extrusion of the elastomeric material between the pillar
inserts and the tubular member.
[0016] The pillar inserts include a top plate, a bottom plate and a
reduced cross section rectangular column positioned therebetween
and integrally formed therewith. The top and bottom plates are a
substantially triangular shape and each of the top and bottom
plates includes a guide lip and a guide shoulder. The guide lips
and guide shoulders of adjacent top plates and the guide lips and
guide shoulders of adjacent bottom plates coact to provide an
irising motion to the top and bottom plates as the top and bottom
plates move and seat against different diameter tubular members.
The simultaneous movement of the top and bottom plates of the
insert allows the top and bottom plates to move and seat against
the tubular member.
[0017] A principal object of the present invention is to provide a
variable bore ram packer that allows sealing over a wide range of
tubular member diameters that minimizes the force required to
operate the variable bore ram packer.
[0018] Another object of the present invention is to provide a
variable bore ram packer that will reliably maintain a seal against
different sized tubular members while minimizing damage to the
elastomeric sealing element of the packer.
[0019] A final object of the present invention is to provide a
variable bore ram packer that can utilize a rubber compound with
higher moduli of elasticity to seat and seal around tubular members
within a designated size range.
[0020] These with other objects and advantages of the present
invention are pointed out with specificness in the claims annexed
hereto and form a part of this disclosure. A full and complete
understanding of the invention may be had by reference to the
accompanying drawings and description of the preferred
embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] These and other objects and advantages of the present
invention are set forth below and further made clear by reference
to the drawings, wherein:
[0022] FIG. 1 is a perspective view with a cutaway section of the
variable bore ram packer of the present invention installed in a
typical ram-type blowout preventer used in oil and gas drilling
operations.
[0023] FIG. 2 is a perspective view of the variable bore ram packer
of the present invention in an exploded view.
[0024] FIG. 3 is a perspective view of the pillar insert for the
variable bore ram packer.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0025] With reference to the drawings, and particularly to FIG. 1,
an isometric view of a ram type blowout preventer 10 used in oil
and gas drilling operations is shown. The ram type blowout
preventer 10 includes a body or housing 12 with a vertical bore 14
and laterally disposed ram guideways 16. Bonnet assemblies 18 are
mounted to the body 12 with suitable securing means such as studs
or bolts 20 and aligned with laterally disposed guideways 16. Each
bonnet assembly 18 includes an actuation means 22, including a
piston 24 and connecting rod 26. While only one guideway 16 and
actuation means 22 is shown, it is understood by those of ordinary
skill in the art that there is a pair of opposed guideways 16 and
actuation means 22. Each connecting rod 26 is connected to a ram 28
which includes the variable bore ram packer 30 of the present
invention. Actuation means 22 allows ram 28 and variable bore ram
packer 30 to be reciprocated within guideways 16 or "opening and
closing the rams" as it is referred to in the industry.
[0026] Variable bore ram packer 30 is shown in an exploded view in
FIG. 2 to aid in understanding the relationship between the parts.
Variable bore ram packer 30 includes packer member 32 of an
elastomeric material with suitable rheological characteristics and
pillar inserts 34 molded into one unitary structure with pillar
inserts 34 arranged around a central semi-circular opening 36 to
form an insert array 38 that is sized to fit closely about a
tubular member. Packer pins 40 are molded into variable bore ram
packer 30 for connecting variable bore ram packer 30 to ram 28.
Packer member 32 is molded to form side packers 42 on its lateral
edges. Ram 28 includes top seal 44 on its upper face. Top seal 44
and side packers 42 combine to seal ram 28 in guideways 16 of ram
type blowout preventer 10 in a manner well known to those of
ordinary skill in the art. When rams 28 are closed around a tubular
member disposed in bore 14 of ram type blowout preventer 10, packer
members 32 seal around the tubular member in a manner to be
described more fully hereinafter.
[0027] As seen in exploded view in FIG. 2 and in an enlarged view
in FIG. 3, pillar inserts 34 include top plate 46, bottom plate 48
and central column 50. Top plate 46 and bottom plate 48 are
substantially triangular in shape with central column 50 positioned
thereon. Central column 50 is integrally formed with top plate 46
and bottom plate 48 by suitable means as casting. Other means of
forming pillar insert 34 such as attaching central column 50 to top
plate 46 and bottom plate 48 by welding are envisioned and within
the scope of the present invention. Central column 50 is shown
having a rectangular cross section but differently shaped cross
sections would be suitable provided they give sufficient bending
strength to pillar insert 34. Central column 50 is sized to have a
relatively small cross section to allow the elastomeric material of
packer member 32 to more easily move around central column 50 as
packer 30 is moved from its open to closed positions. This results
in a substantial reduction in the overall stiffness of packer
member 32. Therefore, packer member 32 and insert array 38 a
greater elasticity or flexibility even though rubber having higher
moduli of elasticity may be used. This allows packer member 32 and
insert array 38 to move with greater ease and more readily seal
against a tubular member in bore 14. Additionally, the increased
flexibility of packer member 32 and insert array 38 aids in
allowing an increased diameter range for the tubular members to be
sealed against.
[0028] Top plate 46 and bottom plate 48 are mirror images of one
another and include guide lip 52 and guide shoulder 54 formed on
top plate 46 and guide lip 56 and guide shoulder 58 formed on
bottom plate 48. Thus, when pillar inserts 34 are molded into
packer member 32, guide lips 52 and guide shoulders 54 of adjacent
top plates 46 overlap. Similarly, guide lips 56 and guide shoulders
58 of adjacent bottom plates 48 overlap. Thus, as seen in FIG. 2,
the assemblies of top plates 46 and bottom plates 48 are arranged
to form semi-circular steel arcs similar to that of an "iris"
shutter of a camera that acts to prevent extrusion of the
elastomeric material of packer member 32 in use.
[0029] The movement and actual irising motion of the insert array
38 is well known to those of skill in art and will be only briefly
described here. With drill pipe or similar tubular member
positioned within the bore 14 of ram type blowout preventer 10
actuation means 22 is operated to move variable bore ram packer 30
to the closed or sealing position. In this position, pillar inserts
34 along with packer member 32 have moved inward. Top plates 46 and
bottom plates 48 have moved spirally inward like the iris of a
camera shutter to form a continuous band of steel around the drill
pipe in bore 14. As pillar inserts 34 move inwardly in an irising
motion, guide lips 52 and guide shoulders 54 of adjacent top plates
46 and guide lips 56 and guide shoulders 58 formed on bottom plates
48 also slide over one another to insure proper movement. The
relatively small cross section of central column 50 serves to
reduce the stress in the elastomeric material or rubber of packer
member 32 as it is forced radially inward to seal against the
tubular member. This reduced cross section allows the use of rubber
with higher moduli of elasticity as previously discussed.
[0030] The construction of our improved variable bore ram packer
will be readily understood from the foregoing description and it
will be seen that we have provided an improved variable bore ram
packer to allow sealing on tubular members within a predetermined
range while reducing stresses in the elastomeric rubber compound.
Furthermore, while the invention has been shown and described with
respect to certain preferred embodiments, it is obvious that
equivalent alterations and modifications will occur to others
skilled in the art upon the reading and understanding of the
specification. The present invention includes all such equivalent
alterations and modifications, and is limited only by the scope of
the appended claims.
* * * * *