U.S. patent application number 12/351609 was filed with the patent office on 2010-07-15 for subsurface safety valve flapper.
This patent application is currently assigned to BJ Services Company. Invention is credited to Robert C. Henschel, Robert Jancha.
Application Number | 20100175887 12/351609 |
Document ID | / |
Family ID | 42299126 |
Filed Date | 2010-07-15 |
United States Patent
Application |
20100175887 |
Kind Code |
A1 |
Henschel; Robert C. ; et
al. |
July 15, 2010 |
Subsurface Safety Valve Flapper
Abstract
A flapper for use as a component of a safety valve designed for
deployment in a well bore having well bore fluids. The flapper
includes a flapper body forming a flapper valve bore therethrough.
The flapper body further forms a groove proximate to the flapper
bore. The flapper also includes a plunger member sized and
configured to be received in the flapper valve bore. The plunger
member includes a first end portion and a second end portion.
Additionally, the flapper includes a leaf spring including a
primary end portion and a secondary end portion, the primary end
portion of the leaf spring detachably attached to the second end
portion of the plunger member and unattached to the flapper body
and the secondary end portion of the leaf spring being sized and
configured to be received and retained in the groove and to bias
the plunger member into the flapper valve bore. Forces exerted on
the flapper body when rotating between an open state and a closed
state during use of the safety valve urge at least a portion of the
leaf spring into the groove.
Inventors: |
Henschel; Robert C.; (The
Woodlands, TX) ; Jancha; Robert; (Humble,
TX) |
Correspondence
Address: |
McGLINCHEY STAFFORD, PLLC;Attn: IP Group
301 Main Street, 14th Floor
Baton Rouge
LA
70802
US
|
Assignee: |
BJ Services Company
Houston
TX
|
Family ID: |
42299126 |
Appl. No.: |
12/351609 |
Filed: |
January 9, 2009 |
Current U.S.
Class: |
166/373 ;
166/332.8 |
Current CPC
Class: |
E21B 2200/05 20200501;
E21B 34/101 20130101 |
Class at
Publication: |
166/373 ;
166/332.8 |
International
Class: |
E21B 34/06 20060101
E21B034/06; E21B 34/00 20060101 E21B034/00; E21B 43/00 20060101
E21B043/00 |
Claims
1. A flapper for use as a component of a safety valve designed for
deployment in a well bore having well bore fluids, the flapper
comprising a flapper body forming a flapper valve bore
therethrough, the flapper body further forming a groove proximate
to the flapper bore; a plunger member sized and configured to be
received in the flapper valve bore, the plunger member comprising a
first end portion and a second end portion; and a leaf spring
comprising a primary end portion and a secondary end portion, the
primary end portion of the leaf spring detachably attached to the
second end portion of the plunger member and unattached to the
flapper body and the secondary end portion of the leaf spring being
sized and configured to be received and retained in the groove and
to bias the plunger member into the flapper valve bore, wherein
forces exerted on the flapper body when rotating between an open
state and a closed state during use of the safety valve urge at
least a portion of the leaf spring into the groove.
2. A flapper according to claim 1 wherein the primary end portion
of the leaf spring is mechanically coupled to the second end
portion of the plunger member.
3. A flapper according to claim 1 wherein the primary end portion
of the leaf spring further defines a leaf spring aperture, wherein
the second end portion of the plunger member is inserted through
the leaf spring aperture and mechanically coupled to the leaf
spring.
4. A safety valve for deployment in a well bore having well bore
fluids wherein the safety valve comprises a flapper in accordance
with claim 1.
5. A flapper according to claim 1 wherein the flapper body is
curved.
6. A flapper according to claim 1 wherein the flapper body further
forms at least one hinge component sized and configured for hinged
attachment to the safety valve.
7. A flapper according to claim 1 wherein at least a portion of the
groove extends distally from the flapper valve bore.
8. A flapper according to claim 1 wherein at least a portion of the
leaf spring extends distally from the flapper valve bore.
9. A flapper according to claim 1 wherein the plunger member
further forms a plunger member bore therethrough.
10. A flapper according to claim 9 wherein the plunger member
further forms at least one fluid pathway in fluid communication
with the plunger member bore, the plunger member bore and fluid
pathway providing at least one fluid passageway through the flapper
valve bore when the plunger member is disposed in the flapper valve
bore but is sufficiently displaced from the flapper valve bore so
that the fluid passageway is in fluid communication with both an
upstream side of the flapper body and a downstream side of the
flapper body.
11. A method for equalizing differential pressure across a safety
valve deployed in a well bore having well bore fluids, the method
comprising deploying the safety valve in the well bore, the safety
valve comprising a flapper, wherein the flapper comprises a flapper
body forming a flapper valve bore therethrough, the flapper body
further forming a groove proximate to the flapper bore; biasing a
plunger member in the flapper valve bore by coupling the plunger
member to a leaf spring comprising a primary end portion and a
secondary end portion, the plunger member being sized and
configured to be received in the flapper valve bore and further
comprising a first end portion and a second end portion and the
primary end portion of the leaf spring being coupled to the second
end portion of the plunger member and the secondary end portion of
the leaf spring being sized and configured to be received and
retained in the groove; and displacing the plunger member to allow
fluid to flow from a portion of the well bore having higher
pressure to a portion of the well bore having lower pressure,
wherein displacing the plunger member causes the primary end
portion of the leaf spring to rotate about the latitudinal axis of
the flapper, whereby the pressure differential across the safety
valve is equalized.
12. A method according to claim 11 wherein the plunger member forms
a plunger member bore therethrough, the plunger member bore further
forming at least one fluid pathway in fluid communication with the
plunger member bore, the plunger member bore and fluid pathway
providing at least one fluid passageway through the flapper valve
bore when at least a portion of the plunger member is displaced
from the flapper valve bore and the fluid passageway further
allowing fluid to flow from the portion of the well bore having
higher pressure to the portion of the well bore having lower
pressure thereby equalizing the pressure across the flapper.
13. A method according to claim 11 further comprising the step of
opening the flapper after the pressure differential has been
equalized.
14. A method for retaining a flapper valve in a flapper in a safety
valve designed for deployment in a well bore, the method comprising
providing a flapper valve bore in the flapper, the flapper valve
bore extending through the flapper and the flapper further defining
a groove extending distally from the flapper valve bore, and
biasing a plunger member into the flapper valve bore by coupling
the plunger member to a leaf spring, the leaf spring disposed in
the groove and extending distally from the plunger member, whereby
the leaf spring is urged into the groove when forces are exerted on
the flapper thereby retaining the plunger member in the flapper
valve bore.
15. A method according to claim 14 further comprising the step of
deploying the safety valve in the well bore.
Description
TECHNICAL FIELD
[0001] This invention relates to subsurface safety valves for
deployment in hydrocarbon producing wells, particularly subsurface
safety valves comprising flappers.
BACKGROUND
[0002] Typically, a hydrocarbon producing well will include a
subsurface safety valve to seal off a section of production tubing
in the event of an emergency, e.g., damage to the well head. This
type of valve is usually activated from the surface using a
hydraulic control system with control lines that run from the
surface to the subsurface safety valve. The valve typically
comprises a valve housing and a closure member used to seal the
production tubing in the well bore. The closure member typically
used is a flapper which is hingedly attached to the valve housing
and rotatable throughout an arc of ninety degrees between an open
and closed position. The control system uses hydraulic pressure to
move a hollow tube, usually referred to as a flowtube, downwardly
against the flapper and a return spring, thereby disposing the
flapper in an open position such that hydrocarbons may flow in the
production tubing. Once, the hydraulic pressure is lost in the
system, the flow tube moves upwardly thereby allowing the return
spring to bias the flapper in a closed position effectively sealing
off from the surface the flow of hydrocarbons in the production
tubing.
[0003] Once the flapper is in the closed position, formation
pressure accumulates on the upstream side of the flapper. This
increase in pressure causes a high pressure differential across the
flapper making the opening of the flapper difficult. One manner to
solve this problem is to incorporate an equalizing or bleed valve
assembly in the flapper. Such an equalizing valve assembly
typically comprises a plunger or like member, a spring, and
hardware to fasten the spring and plunger to the flapper. The
plunger, typically biased against the flapper by the spring, is
displaced to allow the pressure differential to dissipate across
the flapper thereby reducing the difficulty in disposing the
flapper in an open position.
SUMMARY OF THE INVENTION
[0004] It now has become apparent that a need exists for a durable
equalizing valve assembly which can withstand the extreme forces
generated by the and on the flapper when it slams closed during
use. The flapper is commonly exposed to extreme forces during
closing. Those forces may damage the equalizing valve assembly
components, especially the hardware used to fasten the equalizing
valve assembly to the flapper.
[0005] The present invention is deemed to meet the foregoing need,
amongst others, by providing in at least one embodiment, a flapper
comprising a durable and efficient flapper valve assembly capable
of dissipating a pressure differential across the flapper. In at
least one embodiment of the present invention, the flapper valve
assembly is designed to withstand high external forces created by
the slamming of the flapper when closing by requiring no additional
hardware to fasten the components of the flapper valve assembly to
the flapper.
[0006] One embodiment of the present invention provides a flapper
for use as a component of a safety valve designed for deployment in
a well bore having well bore fluids. The flapper comprises a
flapper body forming a flapper valve bore therethrough. The flapper
body further forms a groove proximate to the flapper bore. The
flapper also comprises a plunger member sized and configured to be
received in the flapper valve bore, the plunger member comprising a
first end portion and a second end portion. Additionally, the
flapper comprises a leaf spring comprising a primary end portion
and a secondary end portion, the primary end portion of the leaf
spring detachably attached to the second end portion of the plunger
member and unattached to the flapper body and the secondary end
portion of the leaf spring being sized and configured to be
received and retained in the groove and to bias the plunger member
into the flapper valve bore. Forces exerted on the flapper body
when rotating between an open state and a closed state during use
of the safety valve urge at least a portion of the leaf spring into
the groove. In this way, the components of the flapper maintain
their structural relationship with one another despite being
exposed to the forces associated with the repeated opening and
closing of the safety valve during operation.
[0007] Another embodiment of this invention is a method for
equalizing differential pressure across a safety valve deployed in
a well bore having well bore fluids. The method comprises deploying
the safety valve in the well bore. The safety valve comprises a
flapper, wherein the flapper comprises a flapper body forming a
flapper valve bore therethrough. The flapper body further forms a
groove proximate to the flapper bore. The method further comprises
biasing a plunger member in the flapper valve bore by coupling the
plunger member to a leaf spring comprising a primary end portion
and a secondary end portion. The plunger member is sized and
configured to be received in the flapper valve bore and further
comprises a first end portion and a second end portion. The primary
end portion of the leaf spring is coupled to the second end portion
of the plunger member. The secondary end portion of the leaf spring
is sized and configured to be received and retained in the groove.
The method further comprises displacing the plunger member to allow
fluid to flow from a portion of the well bore having higher
pressure to a portion of the well bore having lower pressure.
Displacing the plunger member causes the primary end portion of the
leaf spring to rotate about the latitudinal axis of the flapper,
whereby the pressure differential across the safety valve is
equalized.
[0008] Still yet, another embodiment of the present invention
provides a method for retaining a flapper valve in a flapper in a
safety valve designed for deployment in a well bore. The method
comprises providing a flapper valve bore in the flapper. The
flapper valve bore extends through the flapper and the flapper
further defines a groove extending distally from the flapper valve
bore. The method further comprises biasing a plunger member into
the flapper valve bore by coupling the plunger member to a leaf
spring. The leaf spring is disposed in the groove and extends
distally from the plunger member. The leaf spring is urged into the
groove when forces are exerted on the flapper and thereby retains
the plunger member in the flapper valve bore.
[0009] These and other features of this invention will be still
further apparent from the ensuing description, drawings, and
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a cross sectional view of a subsurface safety
valve, wherein the flapper is in a closed state consistent with one
embodiment of the present invention.
[0011] FIG. 2 is a cross sectional view of a subsurface safety
valve, wherein the flapper is in a open state consistent with one
embodiment of the present invention.
[0012] FIG. 3 is a perspective view of a flapper consistent with
one embodiment of the present invention.
[0013] FIG. 4 is a cross sectional view of a flapper body and a
flapper valve consistent with one embodiment of the present
invention.
[0014] FIG. 5 is a top plan view of a flapper consistent with one
embodiment of the present invention.
[0015] FIG. 6 is a perspective view of a plunger member comprising
a plurality of fluid pathways consistent with one embodiment of the
present invention.
[0016] FIG. 7 is a cross-sectional view of a plunger member
comprising a plunger member bore and a plurality of fluid pathways
consistent with one embodiment of the present invention.
[0017] FIG. 8 is a top plan view of a plunger member comprising a
plunger member bore and a plurality of fluid pathways consistent
with one embodiment of the present invention
[0018] In each of the above figures, like numerals are used to
refer to like or functionally like parts among the several
figures.
FURTHER DETAILED DESCRIPTION OF THE INVENTION
[0019] Illustrative embodiments of the invention are described
below as they might be employed in the construction and use of a
subsurface safety valve flapper and methods according to the
present invention. In the interest of clarity, not all features of
an actual implementation are described in this specification. It
will be of course appreciated that in the development of such an
actual embodiment, numerous implementation-specific decisions must
be made to achieve the developers' specific goals, such as
compliance with system-related and business-related constraints,
which will vary from one implementation to another. Moreover, it
will be appreciated that such a development effort might be complex
and time-consuming, but would nevertheless be a routine undertaking
for those of ordinary skill in the art having the benefit of this
disclosure.
[0020] Turning now to the figures, FIGS. 1 and 2 illustrate a
subsurface safety valve 10 consistent with at least one embodiment
of the present invention. When deployed in a well bore (not shown),
subsurface safety valve 10 is commonly incorporated into the
production tubing (not shown). Subsurface safety valve 10 includes
a valve housing 12 comprising a first end portion 14 and a second
end portion 16. First end portion 14 of the housing 12 is threaded
for attachment to an adjacent string of production tubing (not
shown) and second end portion 16 of the housing 12 is threaded for
attachment with an adjacent section of production tubing (not
shown). The valve housing 12 further defines a bore 18 for fluid
flow there through. The valve housing 12 further includes an
enlarged central portion 20, wherein an annular valve seat 22 is
secured within the central portion 20. As illustrated in FIG. 1,
the subsurface safety valve 10 would function to inhibit fluid flow
from the direction of the second end portion 16 to the first end
portion 14 of the valve housing 12. Thus, the second end portion 16
will be considered upstream to the first end portion 14.
[0021] As illustrated in FIGS. 1 and 2, subsurface safety valve 10
further comprises a flapper 24, wherein the flapper 24 is hingedly
secured to the valve seat 22 by hinge pin 26. The flapper 24 may
rotate about the hinge pin 26 in approximately a 90.degree. range
of motion, between an open state (shown in FIG. 2) and a closed
state, as shown in FIG. 1. In the closed state, flapper 24 is in
contact and seated on the valve seat 22, thereby forming a sealing
relationship with the valve seat 22. A torsion spring (not shown)
biases the flapper 24 in a closed state, as shown in FIG. 2. With
the flapper 24 and valve seat 22 forming the sealing relationship
as shown in FIG. 1, the subsurface safety valve 10 inhibits fluid
flow from the upstream portion of the well bore to the downstream
portion of the well bore. As illustrated, the flapper 24 further
comprises a pressure equalizing assembly 28, the structure and
function of which will be discussed further below.
[0022] An actuation member 30, which may be a conventional
actuation tube or sleeve, is disposed within the housing bore 18
downstream of the valve seat 22 and may be shifted along the
longitudinal axis of the housing bore 18, typically by means of
hydraulic pressure or shifting tools; however, actuation member 30
may be shifted by other means known in the art. Actuation member 30
is shifted between an upper position (as shown in FIG. 1) and a
lower position (as shown in FIG. 2). Actuation member 30 comprises
a lower end portion 32, the lower end portion 32 may be
substantially flat. Actuation member 30 is shifted to allow the
flapper 24 to rotate between open and closed states depending on
the position of the actuation member 30.
[0023] Turning now to FIGS. 3 through 5, the flapper 24 and
pressure equalizing assembly 28 may be better understood. Flapper
24 comprises a flapper body 34, wherein the flapper body 34 is
curved. The flapper body 34 is a generally saddle-shaped disc,
wherein the flapper body 34 is arcuately curved to provide a
curvature that approximately matches the interior surface of the
housing 12. As shown in FIGS. 3 and 4, the flapper body 34
arcuately curves away from a latitudinal axis of the flapper body
34 when viewed from the upstream face 38 of the flapper 24. The
flapper body 34 is curved in order to allow for a smaller outer
diameter of the valve housing 12 while increasing the surface
sealing contact between the flapper body 34 and the valve seat 22.
The flapper body 24 further forms a rounded radial perimeter 36
that is sized and configured to retain a sealing relationship with
the valve seat 22 when the flapper 24 is in contact with the valve
seat 22. The flapper body 34 comprises an upstream face 38 and a
downstream face 40, the upstream face 38 receiving the fluid
pressure from the upstream portion of the well bore when the
flapper 24 is in a closed state. The downstream face 40 comprises
contact portions (not shown), the contact portions sized and
configured to be contacted by the actuation member 30 to facilitate
the rotation of the flapper 24 between states. The contact portions
may be substantially flat so that the contact portions may contact
the lower end portion 32 of the actuation member 30 in a mating
fashion. The flapper body 34 further forms at least one hinge
component 42, illustrated as a hinge, sized and configured for
hinged attachment to the safety valve 10, wherein the hinged
component 42 extends radially from the flapper body.
[0024] As illustrated in FIGS. 3 through 5, flapper body 34 further
forms a flapper valve bore 44 therethrough, the location of the
flapper valve bore 44 being within the contact portion of the
downstream face 40 of the flapper 24. Flapper body 34 further forms
a groove 46 proximate to the flapper bore 44 in the upstream face
38 of the flapper 24. Groove 46 extends distally from the flapper
valve bore 44 toward the portion of the flapper body 34 directly
opposing the hinged component 42.
[0025] Flapper 24 further comprises a plunger member 48,
illustrated in FIGS. 6 through 8 as a plunger, is sized and
configured to be received in the flapper valve bore 44. Plunger 48
is further sized and configured to shift within the flapper valve
bore 44; however, plunger 48 forms a sealing relationship with the
flapper valve bore 44 when disposed within the valve bore 44.
Plunger 48 comprises a first end portion 50 and a second end
portion 52, wherein the first end portion 50 of the plunger 48
protrudes above the downstream face 40 of the flapper 24. The first
end portion 50 of the plunger 48 may be substantially flat so that
the substantially flat lower end portion 32 of the actuation member
30 may be in a mating fashion with the first end portion 50 of the
plunger 48 when actuation member 30 is shifted and placed in
contact with the first end portion 50 of the plunger 48.
[0026] Plunger 48 further forms a plunger member bore 54
therethrough, as illustrated as a plunger bore in FIGS. 7 and 8.
Plunger bore 54 comprises a first end 56 and a second end 58,
wherein the first end 56 is located at the first end portion 50 of
the plunger 48 and is in fluid communication with the upstream
portion of the well bore. Plunger 48, as illustrated, is
cylindrical in form and further comprises a continuous sidewall 60.
Plunger 48 further forms at least one fluid pathway 62 in fluid
communication with the plunger member bore 54. Fluid pathway 62
extends from the plunger bore 54 to the sidewall 60 of the plunger
48. Plunger bore 54 and fluid pathway 62 provide a fluid passageway
64 through the flapper valve bore 54 when the plunger 48 is
disposed in the flapper valve bore 44 but is sufficiently displaced
from the flapper valve bore 44 so that the fluid passageway 64 is
in fluid communication with both an upstream side of the flapper 24
and a downstream side of the flapper 24.
[0027] As shown in FIGS. 3 through 5, flapper 24 further comprises
a leaf spring 66. As illustrated, leaf spring 66 extends distally
from the flapper valve bore 44. Leaf spring 66 comprises a primary
end portion 68 and a secondary end portion 70. The primary end
portion 68 of the leaf spring 66 is detachably attached to the
second end portion 52 of the plunger 48 and unattached to the
flapper body 34 and the secondary end portion 70 of the leaf spring
66 is sized and configured to be received and retained in the
groove 46 and to bias the plunger 48 into the flapper valve bore
44. The primary end portion 68 of the leaf spring 66 may further
define a leaf spring aperture 72, wherein the second end portion 52
of the plunger 48 may be inserted through the leaf spring aperture
72 and mechanically coupled to the leaf spring 66. The leaf spring
66 is received and retained in the groove 46 such that forces
exerted on the flapper body 34 when rotating between an open state
and a closed state during use of the safety valve 10 urge at least
a portion of the leaf spring 66 into the groove 46.
[0028] Plunger 48 is movably disposed within the flapper valve bore
44 between an open position and a closed position. In the open
position, fluid may flow through the fluid passageway 64 from the
upstream portion of the well bore to the downstream portion of the
well bore. In its normal state, plunger 48 is biased in the closed
position by the leaf spring 66 such that the plunger 48 creates a
sealing relationship with the flapper valve bore 44 so that fluid
is unable to flow through the fluid passageway 64. In the closed
position, first end portion 50 of the plunger 48 extends above the
contact portion (not shown) of the flapper body 34.
[0029] In operation, the subsurface safety valve 10 is opened by
moving the flapper 24 from the closed position illustrated in FIG.
1 to the open position illustrated in FIG. 2. This is accomplished
by displacing the actuation member 30 from its upper position shown
in FIG. 1 downward toward the upstream portion of the well bore
until the lower end portion 32 of the actuation member 30 contacts
the first end portion 50 of the plunger 48. This contact urges the
plunger 48 into an open position, thereby compressing the leaf
spring 66. Fluid from the upstream portion of the well bore may now
flow to the downstream portion of the well bore. Thus, pressure
across the flapper 24 is reduced or equalized. As the actuation
member 30 further moves in the upstream direction towards its lower
position, the actuation member 30 contacts the contact portions of
the flapper body 34, thereby bringing the actuation member 30 and
contact portions into mating contact and allows the flapper 24 to
be urged into an open position as the actuation member 30 travels
to its lower position.
[0030] In order to close the subsurface safety valve 10, the
actuation member 30 is moved upwardly in the downstream direction
towards the upper position of the actuation member 30. As the
actuation member 30 moves upward, the torsion spring (not shown)
urges the flapper 24 towards its closed state. When the production
tubing (not shown) incorporating the subsurface safety valve 10
contains fluid flowing at a high flow rate or under significant
pressure, the flapper 24 may slam shut against the valve seat 22
with tremendous force. This force actually aids in retaining the
components of the pressure equalizing assembly 28, namely the leaf
spring 66 and plunger 48, disposed in the flapper body 34 by urging
the leaf spring 66 into the groove 46 when such forces slam the
flapper 24 against the valve seat 22. By providing a groove 46 in
the flapper body 34 and minimizing the amount of hardware in the
pressure equalizing assembly 28, it extremely unlikely that any
component of the pressure equalizing assembly 28 would become
dislodged from the subsurface safety valve 10.
[0031] One of ordinary skill in the art will understand that the
components of the subsurface safety valve, including the flapper
body and pressure equalizing assembly, may be made from high
strength steel materials, composites or non-elastomeric
materials.
[0032] Except as may be expressly otherwise indicated, the article
"a" or "an" if and as used herein is not intended to limit, and
should not be construed as limiting, the description or a claim to
a single element to which the article refers. Rather, the article
"a" or "an" if and as used herein is intended to cover one or more
such elements, unless the text expressly indicates otherwise.
[0033] This invention is susceptible to considerable variation
within the spirit and scope of the appended claims.
* * * * *