U.S. patent application number 14/131508 was filed with the patent office on 2014-06-26 for ball valve.
This patent application is currently assigned to Expro North Sea Limted. The applicant listed for this patent is Alistair Tennant. Invention is credited to Alistair Tennant.
Application Number | 20140175317 14/131508 |
Document ID | / |
Family ID | 44652375 |
Filed Date | 2014-06-26 |
United States Patent
Application |
20140175317 |
Kind Code |
A1 |
Tennant; Alistair |
June 26, 2014 |
BALL VALVE
Abstract
A ball valve comprises a housing, a ball seat arranged in the
housing and a ball member mounted within the housing and being
rotatable relative to the ball seat between open and closed
positions. The ball seat and ball member define respective through
bores each having a bore edge, wherein the bore edge of at least
one of the valve seat and ball member defines a recessed cutting
region for cutting a body extending at least partially through the
valve upon closure of the ball member.
Inventors: |
Tennant; Alistair;
(Aberdeen, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Tennant; Alistair |
Aberdeen |
|
GB |
|
|
Assignee: |
Expro North Sea Limted
Aberdeen, Aberdennshire
GB
|
Family ID: |
44652375 |
Appl. No.: |
14/131508 |
Filed: |
July 24, 2012 |
PCT Filed: |
July 24, 2012 |
PCT NO: |
PCT/GB2012/051770 |
371 Date: |
March 12, 2014 |
Current U.S.
Class: |
251/315.01 |
Current CPC
Class: |
E21B 2200/04 20200501;
E21B 33/043 20130101; E21B 29/04 20130101; E21B 34/102 20130101;
E21B 34/04 20130101 |
Class at
Publication: |
251/315.01 |
International
Class: |
E21B 29/04 20060101
E21B029/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 27, 2011 |
GB |
1112883.2 |
Claims
1. A ball valve comprising: a housing; a ball seat arranged in the
housing; a ball member mounted within the housing and being
rotatable relative to the ball seat between open and closed
positions; wherein the ball seat and ball member define respective
through bores each having a bore edge, and wherein the bore edge of
at least one of the valve seat and ball member defines a recessed
cutting region for cutting a body extending at least partially
through the valve upon closure of the ball member.
2. The ball valve according to claim 1, wherein the respective
through bores of the ball seat and ball member define a flow path
through the valve, wherein the ball member is rotated relative to
the ball seat to misalign the respective through bores to prevent
or restrict flow through the valve, and is rotated relative to the
ball seat to align the respective through bores to permit or
increase flow through the valve.
3. The ball valve according to claim 1, defining or forming part of
at least one of a Subsea Test Tree (SSTT), a retainer valve and a
lubricator valve.
4. The ball valve according to claim 1, wherein the recessed
cutting region is configured to cut an elongate body including at
least one of tubing, coiled tubing, wireline, slickline and a tool
string.
5. The ball valve according to claim 1, wherein both the ball seat
and ball member define a recessed cutting region.
6. The ball valve according to claim 1, wherein only one of the
ball seat and ball member define a recessed cutting region.
7. The ball valve according to claim 6, wherein only the ball
member defines a recessed cutting region.
8. The ball valve according to claim 1, wherein a recessed cutting
region is recessed relative to an associated through bore.
9. The ball valve according to claim 1, wherein a recessed cutting
region defines a cutting edge.
10. The ball valve according to claim 1, wherein a recessed cutting
region defines at least two cutting edges to permit simultaneous
cutting into separate regions of a body at least upon initial
contact with the body.
11. The ball valve according to claim 10, wherein the cutting edges
define respective points of cutting contact with a body during
cutting thereof.
12. The ball valve according to claim 11, wherein during initial
contact with a body the at least two points of cutting contact are
offset from a central region of the body, and during cutting the at
least two points of cutting contact with the body propagate
relative to the body until converged together.
13. The ball valve according to claim 10, wherein the at least two
cutting edges are defined by two distinct cutting edges.
14. The ball valve according to claim 10, wherein the at least two
cutting edges are defined by separate regions of a single cutting
edge.
15. The ball valve according to claim 10, wherein the at least two
cutting edges are aligned substantially obliquely relative to a
rotation axis of the ball member.
16. The ball valve according to claim 1, wherein a recessed cutting
region is defined by a v-shaped notch.
17. The ball valve according to claim 1, wherein the bore edge of
at least one of the valve seat and ball member defines a single
recessed cutting region.
18. The ball valve according to claim 1, wherein the bore edge of
at least one of the valve seat and ball member defines at least two
recessed cutting regions.
19. The ball valve according to claim 1, wherein a recessed cutting
region comprises a projection to pierce a body.
20. The ball valve according to claim 1, wherein the ball member
defines a sealing area which cooperates with an appropriate sealing
area of the ball seat, at least when the valve is in a closed
configuration.
21. The ball valve according to claim 20, wherein a recessed
cutting region is defined within the ball member, wherein said
cutting region is recessed towards the sealing area.
22. The ball valve according to claim 1, wherein the housing is
securable in-line with a fluid conduit system, wherein the ball
seat and ball member cooperate to control flow along the fluid
conduit system.
23. The ball valve according to claim 1, wherein the housing is
securable in-line with a landing string.
24. The ball valve according to claim 1, wherein the housing
comprises first and second connectors for securing in-line with a
fluid conduit system.
25. The ball valve according to claim 24, wherein at least one of
the first and second connectors comprises a flange connector.
26. The ball valve according to claim 1, wherein the housing
comprises an outer housing configured to be mechanically secured
in-line with a fluid conduit system and an inner housing located
within the outer housing and configured to contain pressure.
27. The ball valve according to claim 26, wherein the outer housing
comprises a connection arrangement for permitting mechanical
connection with a fluid conduit system.
28. The ball valve according to claim 27, wherein the connection
arrangement comprise first and second connectors for securing
in-line with a fluid conduit system.
29. The ball valve according to claim 28, wherein at least one of
the first and second connectors comprises a flange connector.
30. The ball valve according to claim 28, wherein at least one of
the first and second connectors defines a preloaded connector.
31. The ball valve according to claim 26, wherein the inner housing
is axially contained within the outer housing.
32. The ball valve according to claim 26, wherein the ball seat is
axially contained between the inner housing and the outer
housing.
33. The ball valve according to claim 26, wherein the outer housing
comprises an axially extending wall section to encapsulate the
inner housing.
34. The ball valve according to claim 26, wherein the outer housing
is split.
35. The ball valve according to claim 26, wherein the outer housing
is longitudinally split.
36. The ball valve according to claim 26, wherein the outer housing
comprises at least two housing segments.
37. The ball valve according to claim 36, wherein the housing
segments are securable together when in a closed configuration.
38. The ball valve according to claim 37, wherein the housing
segments are secured together in a closed configuration when the
outer housing is secured to a fluid conduit system.
39. The ball valve according to claim 37, wherein the housing
segments are secured along a length of separation.
40. The ball valve according to claim 37, wherein the housing
segments are secured together by a bolting arrangement.
41. The ball valve according to claim 36, wherein adjacent segments
comprise one or more connecting portions extending at least
partially along the length of split defined between the adjacent
housing segments, wherein opposing connecting portions of each
segment are secured together.
42. The ball valve according to claim 26, wherein at least a
portion of the outer housing defines a generally cylindrical outer
profile.
43. The ball valve according to claim 26, wherein at least a
portion of the outer housing defines a non-cylindrical outer
profile having different dimensions in mutually perpendicular
lateral directions.
44. The ball valve according to claim 26, wherein the inner housing
is isolated from mechanical connection with a fluid conduit
system.
45. The ball valve according to claim 1, comprising a plurality of
respective ball seats and ball members.
46. A method for isolating a fluid conduit system having a body
extending internally therethrough, comprising: securing a ball
valve in-line within the fluid conduit system, wherein the ball
valve comprises a housing, a ball seat arranged in the housing and
a ball member mounted within the housing and being rotatable
relative to the ball seat between open and closed positions,
wherein the ball seat and ball member define respective through
bores each having a bore edge, and wherein the bore edge of at
least one of the valve seat and ball member defines a recessed
cutting region; and rotating the ball member to close the valve and
to cut a body extending at least partially through the valve with
the recessed cutting region.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a ball valve configured for
shearing a body upon closure. The present invention in particular,
but not exclusively, relates to a ball valve for use in a landing
string arrangement, for example for use within a subsea test
tree.
BACKGROUND TO THE INVENTION
[0002] Landing strings are used in the oil and gas industry for
through-riser deployment of equipment, such as completion
architecture, well testing equipment, intervention tooling and the
like into a subsea well from a surface vessel. When in a deployed
configuration the landing string extends between the surface vessel
and the wellhead, for example a wellhead Blow Out Preventor (BOP).
While deployed the landing string provides many functions,
including permitting the safe deployment of wireline or coiled
tubing equipment through the landing string and into the well,
providing the necessary primary well control barriers and
permitting emergency disconnect while isolating both the well and
landing string.
[0003] Wireline or coiled tubing deployment may be facilitated via
a lubricator valve which is located proximate the surface vessel,
for example below a rig floor.
[0004] Well control and isolation in the event of an emergency
disconnect is provided by a suite of valves, typically ball valves,
which are located at a lower end of the landing string, normally
positioned inside the central bore of the BOP. The valve suite
includes a lower valve assembly called the subsea test tree (SSTT)
which provides a safety barrier to contain well pressure, and an
upper valve assembly called the retainer valve which isolates the
landing string contents and can be used to vent trapped pressure
from between the retainer valve and SSTT. A shear sub component
extends between the retainer valve and SSTT which is capable of
being sheared by the BOP if required.
[0005] As noted above, the landing string may accommodate wireline
and/or coiled tubing deployed tools. In this respect the various
valve assemblies, such as in the SSTT, must define sufficiently
large internal diameters to permit unrestricted passage
therethrough. However, the valve assemblies also have outer
diameter limitations, for example as they must be locatable within
the wellhead BOP. Such conflicting design requirements may create
difficulty in, for example, achieving appropriate valve sealing, as
increasing the internal diameter within a restricted outer diameter
may only permit minimal a sealing area to be provided.
[0006] Furthermore, the landing string must be capable of cutting
any wireline or coiled tubing which extends therethrough in the
event of an emergency disconnect. It is known in the art to use one
or more of the valves to shear through the wireline or coiled
tubing upon closure. However, providing a valve with the necessary
cutting capacity may be difficult to achieve within the geometric
design constraints associated with the landing string. For example,
the valve actuators must be of sufficient size to provide the
necessary closing/cutting forces, which may be difficult to
accommodate within the restricted available size.
[0007] Furthermore, in ball valve applications a ball is provided
with a throughbore, wherein an edge of the throughbore functions to
cut through wireline or coiled tubing upon rotation of the ball
towards a closed configuration. Known ball valve designs are such
that the throughbore is circular providing a correspondingly shaped
throughbore edge. The present inventors have discovered that,
particularly with coiled tubing, the cutting forces are applied
initially centrally of the tubing, causing the tubing to collapse,
making subsequent shearing of the collapsed tube difficult and
energy/force intensive.
[0008] The landing string must also be designed to accommodate the
significant in-service loadings, such as the global tension from a
supported lower string (e.g., a test string, completion or the
like), bending loads, valve actuation loading, internal and
external pressures and the like. As the industry continues to move
into fields with increasing formation and water depths, the
resulting structural demands on the landing string also become more
extreme. For example, landing string global tension requirements
far in excess of 4.5 MN (1,000,000 lbf) and wellbore pressures
which can exceed 690 bar (10,000 psi) are typical. Such loadings
must be accommodated across regions including the various valve
assemblies, such as the SSTT. It is therefore necessary to design
the valve housings and appropriate end connections to be capable of
accommodating the global applied tension, bending loads, valve
actuation loading and pressures. This results in the use of thick
walled valve housings, which can compromise the achievable valve
internal diameters and sealing integrity. Furthermore, current
industry standards call for all connections through such landing
string valve assemblies to be configured to avoid separation during
use to improve fatigue performance. Such connections may include
bolted connections of the valve housings into the landing string.
This typically requires significant upsizing of the connections and
establishes further difficulties in achieving sufficiently large
internal diameters within the outer diameter constraints, such as
dictated by the BOP.
SUMMARY OF THE INVENTION
[0009] According to a first aspect of the present invention there
is provided a ball valve comprising: [0010] a housing; [0011] a
ball seat arranged in the housing; [0012] a ball member mounted
within the housing and being rotatable relative to the ball seat
between open and closed positions; [0013] wherein the ball seat and
ball member define respective through bores each having a bore
edge, and wherein the bore edge of at least one of the valve seat
and ball member defines a recessed cutting region for cutting a
body extending at least partially through the valve upon closure of
the ball member.
[0014] The respective through bores of the ball seat and ball
member may define a flow path through the valve. The ball member
may be rotated relative to the ball seat to misalign the respective
through bores to prevent or restrict flow through the valve, and
may be rotated relative to the ball seat to align, for example
coaxially align, the respective through bores to permit or increase
flow through the valve.
[0015] In use, closure of the ball member to prevent or restrict
flow through the valve may also result in any body which at least
partially extends through the valve being cut, for example
partially or fully cut. This arrangement may permit full closure of
the valve member to be achieved without impedance from the
body.
[0016] The ball valve may have numerous applications as might
readily be understood by those of skill in the art. In some
embodiments the ball valve may be configured for use within a
landing string assembly. For example, the ball valve may define or
form part of a Subsea Test Tree (SSTT), a retainer valve, a
lubricator valve or the like.
[0017] A recessed cutting region may be configured to cut an
elongate body, such as tubing, coiled tubing, wireline, slickline,
a tool string or the like. A recessed cutting region may be
configured to cut, for example effectively cut, a generally
circular body. The body may extend at least partially through the
respective through bores of the ball seat and ball member. The body
may extend entirely through the respective through bores of the
ball seat and ball member. In such arrangements the through bores
of the ball seat and ball member may be configured to accommodate a
body to extend at least partially therethrough.
[0018] Both the ball seat and ball member may define a recessed
cutting region. In such an arrangement the respective recessed
cutting regions may be configured similarly, or differently.
Respective recessed cutting regions of the ball seat and ball
member may be generally aligned with each other. Such alignment may
be considered to exist in a plane which is perpendicular to a
rotational axis of the ball member. In other embodiments the
respective recessed cutting regions of the ball seat and ball
member may be misaligned.
[0019] Only one of the ball seat and ball member may define a
recessed cutting region. This arrangement may be advantageous in
that the component which does not comprise a cutting recess may
hold the body being cut in a more central position relative to the
ball seat and ball member, presenting the body in a better position
to be cut. In one embodiment only the ball member may define a
recessed cutting region.
[0020] A recessed cutting region may be recessed relative to an
associated through bore. That is, the recessed cutting region may
be outwardly recessed relative to an associate throughbore.
[0021] A recessed cutting region may be configured to at least
partially receive a body to be cut. The recessed cutting region may
be configured to entirely receive a body to be cut. In some
embodiments, large bodies, for example large diameter bodies may
only partially be received within the recessed cutting region.
[0022] A recessed cutting region may be provided in a leading edge
of one or both of the ball seat and ball member. In this respect
the leading edges of the ball seat and ball member may be
considered to be those edges of the respective through bores which
initially pass each other upon closure of the ball member relative
to the seat.
[0023] Upon closure of the ball member the bore edge of the ball
member throughbore may engage and displace a body which at least
partially extends through the valve until said body is engaged
between the ball member bore edge and the ball seat bore edge and
at least partially received within a recessed cutting region, such
that further rotational movement of the ball member towards a
closed position permits cutting of the body, typically by a
shearing action, by the recessed cutting region.
[0024] A recessed cutting region may define a cutting edge. The
cutting edge may be formed continuously with the edge of an
associated through bore edge.
[0025] A recessed cutting region may define at least two cutting
edges configured to permit simultaneous cutting into separate
regions of a body, for example upon initial contact with the body.
A recessed cutting region may be arranged to define at least two
points of cutting contact with a body during cutting thereof.
During initial contact with the body during cutting thereof the at
least two points of cutting contact may be offset from a central
region of the body. During initial contact with the body the at
least two points of cutting contact may be offset from a central
region of the recessed cutting region. This arrangement may permit
the force of cutting to be divided between the different points of
cutting contact, assisting to prevent adverse compression,
collapsing or the like of the body. Furthermore, this arrangement
may prevent large cutting forces being applied initially centrally
of a body which may assist to prevent collapse of the body, for
example. Also, this arrangement may require less torque through the
ball member to cut the body. Such reduced loading is anticipated to
reduce damage to the components of the ball valve which may assist
in preventing or reducing any damage to sealing regions. During
cutting of a body, the at least two points of cutting contact with
the body may converge together. That is, the at least two points of
cutting contact may propagate relative to the body until converged
together.
[0026] The at least two cutting edges may be defined by two
distinct cutting edges. In some embodiments the at least two
cutting edges may be defined by separate regions of a single
cutting edge.
[0027] The at least two cutting edges may be aligned substantially
obliquely relative to a rotation axis of the ball member.
[0028] At least one cutting edge may be generally straight. At
least one cutting edge may be curved, for example arcuate.
[0029] A recessed cutting region may be defined by a notch
extending into the edge region of an associated through bore.
[0030] A recessed cutting region may be generally v-shaped, for
example defined by a v-shaped notch.
[0031] A recessed cutting region may be arcuate, for example.
[0032] The bore edge of at least one of the valve seat and ball
member may define a single recessed cutting region. The bore edge
of at least one of the valve seat and ball member may define at
least two recessed cutting regions. In such an arrangement at least
two cutting regions may be separated from each other. At least two
cutting regions may merge or overlap each other.
[0033] A recessed cutting region may comprise a projection, for
example a central projection, which may function to pierce the
body, for example centrally of the body.
[0034] A recessed cutting region may comprise a serrated edge.
[0035] The ball valve may comprise one or more inserts located
within a recessed cutting region. The insert may define a cutting
edge. Such an insert may facilitate easier maintenance and the
like. For example, to re-establish a sufficient cutting edge only
the insert need be replaced, rather than the entire ball.
[0036] The ball member may define a sealing area which cooperates
with an appropriate sealing area of the ball seat, at least when
the valve is in a closed configuration. The ball seal area is
rotationally offset from the ball through bore. The recessed
cutting region may be defined within the ball member, wherein said
cutting region is recessed towards the sealing area.
[0037] The housing may be configured to be secured in-line with a
fluid conduit system, wherein the ball seat and ball member may
cooperate to control flow along the fluid conduit system. The fluid
conduit system may be defined by one or more tubing components,
flow equipment such as other valves, flow meters, shear-sub
components or the like. The housing may be configured to be secured
in-line with a landing string.
[0038] The housing may comprise first and second connectors for
securing in-line with a fluid conduit system, such as a landing
string. At least one of the first and second connectors may
comprise a flange connector, such as a bolted flange connector. The
first and second connectors may be configured to be secured to a
similar component, such as tubing, for example. The first and
second connectors may be configured to be secured to different
components. For example, one connector may be configured to be
secured to tubing, and one connector may be configured to be
secured to flow equipment such as another valve or the like.
[0039] The housing may comprise a unitary component.
[0040] Alternatively, the housing may comprise multiple
components.
[0041] The housing may comprise an outer housing configured to be
mechanically secured in-line with a fluid conduit system and an
inner housing located within the outer housing and configured to
contain pressure.
[0042] The outer housing may be defined as a structural housing.
That is, the outer housing may be provided primarily to accommodate
mechanical forces, such as axial and bending forces, associated
with the fluid conduit system while providing minimal or no
pressure containment, for example of internal and/or external
pressures. The inner housing may be defined as a pressure housing.
That is, the inner housing may be provided primarily for pressure
containment, for example of internal and/or external pressures,
while providing minimal or no contribution to accommodating
mechanical loading associated with the fluid conduit system This
arrangement may permit each individual housing to be designed
and/or selected to meet more focussed or specific operational
requirements.
[0043] These divided roles of the first and second housings may
provide a number of advantages, such as reduction in wall
thickness, weight, costs and the like. In particular, the provision
of an outer structural housing and a separate pressure containing
inner housing may permit a reduction in the global housing wall
thickness to be achieved. That is, as the outer housing is not
intended to be pressure containing, the wall thickness of this can
be significantly reduced. Furthermore, as the inner housing is
intended for pressure containment, and not, for example, to
accommodate significant tensile and bending loads, this too can
have a minimal wall thickness for its limited function. As such,
the combined wall thickness can be reduced relative to a single
structure which is designed to be exposed to both mechanical and
pressure loading.
[0044] Reducing the overall wall thickness of the housing may
permit a larger housing inner diameter to be available allowing one
or both of the ball seat and ball member to be increased in size.
This may be particularly advantageous in permitting a sufficient
valve sealing area to be achieved even with the presence of a
recessed cutting region. That is, the recessed cutting region may
encroach into a sealing area of the ball seat and/or ball member,
wherein an increased ball seat and/or ball member, and associated
sealing area may permit such encroachment to be accommodated
without compromising sealing integrity.
[0045] By the outer housing being mechanically secured in-line with
a fluid conduit system mechanical forces, such as tensile forces
and bending forces, may be transmitted across the outer housing.
Such mechanical forces may originate from the fluid conduit system,
such as from the weight of the fluid conduit system or the
like.
[0046] The outer housing may comprise a connection arrangement for
permitting mechanical connection with a fluid conduit system. The
connection arrangement may comprise first and second connectors for
securing in-line with a fluid conduit system. At least one of the
first and second connectors may comprise a flange connector. At
least one of the first and second connectors may define a preloaded
connector. Such preloading may be achieved by use of one or more
preloaded bolt connections. Such preloading may permit the point of
connection from separating during use, for example due to axial and
bending forces. As the inner housing is located internally within
the outer housing and does not include any direct mechanical
connection with the fluid conduit system, any requirement to
provide such a preloaded connector with the inner housing is
eliminated. That is, only the connection between the outer housing
and the fluid conduit system may require preloading, for example to
meet required or preferred industry standards.
[0047] The inner housing may be axially contained within the outer
housing. In such an arrangement any axial loading experienced by
the inner housing, for example due to internal pressures, valve
actuation forces and the like may be transferred to the outer
housing. The inner housing may be axially contained between first
and second connectors of the outer housing.
[0048] The ball seat may be axially contained between the inner
housing, for example an axial end of the inner housing, and the
outer housing, for example a connecting portion of the outer
housing. Such an arrangement may provide a simple modular
construction, permitting ease of assembly while ensuring sufficient
retention of the ball seat within the ball valve. Furthermore, such
an arrangement may eliminate the requirement to provide a
mechanical connection of the ball seat within the ball valve,
providing advantages in terms of, for example, space saving.
[0049] The outer housing may comprise an axially extending wall
section configured to encapsulate the inner housing. As pressure
forces are contained primarily by the inner housing, the wall
thickness of the axially extending wall section of the outer
housing may be minimised.
[0050] The outer housing may define a barrel-type housing.
[0051] The outer housing may be split to permit access to install,
remove, replace, inspect or the like the inner housing. In one
embodiment the outer housing may be longitudinally split, that is,
split along its length. The outer housing may comprise at least two
housing segments. The housing segments may be hingedly connected
together. The housing segments may be configured to be secured
together when in a closed configuration. For example, the housing
segments may be secured together in a closed configuration when the
outer housing is secured to a fluid conduit system, for example via
first and second connectors. The housing segments may be secured
along a length of separation, for example along the length of the
split defined between the different segments. This arrangement may
provide or establish appropriate hoop stiffness within the outer
housing which may be required to resist bending forces, for
example.
[0052] The housing segments may be secured together by a bolting
arrangement. The bolting arrangement may be provided along one or
more sides or regions of separation between different segments.
[0053] The housing segments may be secured together via one or more
tangential bolts.
[0054] Adjacent segments may comprise one or more connecting
portions extending at least partially along the length of split
defined between the adjacent segments, wherein opposing connecting
portions of each segment may be secured together, for example via
bolting. A plurality of connecting portions may be provided on each
adjacent segment. Axially adjacent connecting portions on a single
segment may be separated by a slotted region, such as a laterally
extending slot. Such separation between axially adjacent flange
portions may permit appropriate redirection of stress around and
across this area of connection between segments, for example due to
tensile loading.
[0055] The housing segments may be secured together via one or more
axially extending connecting members, such as a connecting rod,
bolt or the like. In such an arrangement adjacent housing segments
may comprise interleaving portions which are held together via such
an axially extending connecting member.
[0056] As the outer housing is not intended to be pressure
containing any sealing, or at least any significant sealing
arrangements, may not be required between individual housing
segments when secured together.
[0057] At least a portion of the outer housing may define a
generally cylindrical outer profile.
[0058] At least a portion of the outer housing may define a
generally non-cylindrical outer profile having different dimensions
in mutually perpendicular lateral directions. For example, at least
a portion of the outer housing may define a generally oval outer
profile, elliptical outer profile or the like. Such an arrangement
may permit umbilicals or the like to be accommodated between the
valve housing and an outer constraining structure, such as an outer
pipeline, borehole, casing section, riser or the like.
[0059] In some embodiments a connection arrangement, such as a
flange connection arrangement of the outer housing may define a
non-cylindrical profile.
[0060] The outer housing may define one or more axial holes, such
as gun drilled holes, which may accommodate fluid communication,
for example across the entire length of the housing, to provide
hydraulic power to the valve internal components such as actuators
or the like.
[0061] The inner housing may define a generally cylindrical
profile.
[0062] The inner housing may be isolated from mechanical connection
with a fluid conduit system. For example, the inner housing not be
exposed, or may be exposed to a far lower proportion of mechanical
loading associated with the fluid conduit system as the outer
housing. This lack of connection thus eliminates any requirement
for a preloaded connection with the fluid conduit system, for
example as may be required or preferred by industry standards. This
permits space saving to be achieved, for example in terms of
available internal diameter thus allowing larger valve mechanisms
and components, such as the ball seat and ball member, to be
utilised.
[0063] The inner housing may be defined by a pressure containing
sleeve.
[0064] The inner housing may be arranged to accommodate one or both
of the ball seat and ball member. The inner housing may be
configured to accommodate a valve actuator. For example, inner
housing may define a piston cylinder or the like.
[0065] The ball valve may comprise a plurality of respective ball
seats and ball members. Such an arrangement may provide a degree of
redundancy within the ball valve.
[0066] According to a second aspect of the present invention there
is provided a method for isolating a fluid conduit system having a
body extending internally therethrough, comprising: [0067] securing
a ball valve in-line within the fluid conduit system, wherein the
ball valve comprises a housing, a ball seat arranged in the housing
and a ball member mounted within the housing and being rotatable
relative to the ball seat between open and closed positions,
wherein the ball seat and ball member define respective through
bores each having a bore edge, and wherein the bore edge of at
least one of the valve seat and ball member defines a recessed
cutting region; and [0068] rotating the ball member to close the
valve and to cut a body extending at least partially through the
valve with the recessed cutting region.
[0069] According to a third aspect of the present invention there
is provided a sub sea test tree comprising:
[0070] a housing; [0071] a ball seat arranged in the housing;
[0072] a ball member mounted within the housing and being rotatable
relative to the ball seat between open and closed positions; [0073]
wherein the ball seat and ball member define respective through
bores each having a bore edge, and wherein the bore edge of at
least one of the valve seat and ball member defines a recessed
cutting region for cutting a body extending at least partially
through the valve upon closure of the ball member.
[0074] The housing may be configured to be located within a Blow
Out Preventor (BOP).
[0075] According to a fourth aspect of the present invention there
is provided a landing string assembly comprising a valve, wherein
the valve comprises: [0076] a housing; [0077] a ball seat arranged
in the housing; [0078] a ball member mounted within the housing and
being rotatable relative to the ball seat between open and closed
positions; [0079] wherein the ball seat and ball member define
respective through bores each having a bore edge, and wherein the
bore edge of at least one of the valve seat and ball member defines
a recessed cutting region for cutting a body extending at least
partially through the valve upon closure of the ball member.
[0080] The valve may define a sub sea test tree.
[0081] According to a fifth aspect of the present invention there
is provided a valve comprising: [0082] an outer housing configured
to be mechanically secured with a fluid conduit system; [0083] an
inner housing located within the outer housing and configured to
contain pressure; and [0084] a valve mechanism mounted within the
inner housing.
[0085] The outer housing may be mechanically secured in-line with a
fluid conduit system.
[0086] According to a sixth aspect of the present invention there
is provided a ball valve comprising: [0087] a housing; [0088] a
ball seat arranged in the housing; [0089] a ball member mounted
within the housing and being rotatable relative to the ball seat
between open and closed positions; [0090] wherein a leading edge of
at least one of the ball valve and ball seat comprises a v-shaped
notch for cutting a body extending at least partially through the
valve upon closure of the ball member.
[0091] Features defined in relation to one aspect defined above may
be associated with any other aspect.
BRIEF DESCRIPTION OF THE DRAWINGS
[0092] These and other aspects of the present invention will now be
described, by way of example only, with reference to the
accompanying drawings, in which:
[0093] FIG. 1 illustrates a landing string arrangement which
includes features according to embodiments of aspects of the
present invention;
[0094] FIG. 2 is a cross-sectional view of a ball valve in
accordance with an embodiment of the present invention;
[0095] FIG. 3 is a perspective view of a ball member which may be
utilised in the ball valve of FIG. 2, in accordance with an
embodiment of the present invention;
[0096] FIG. 4 is a cross-sectional view of the ball member of FIG.
3 shown in combination with an associated ball seat;
[0097] FIG. 5 is an top elevational view of the ball member, ball
seat and coiled tubing shown in FIG. 4;
[0098] FIG. 6 is a perspective view of a ball member and ball seat
of a ball valve according to a modified embodiment of the present
invention;
[0099] FIGS. 7 and 8 are top elevational views of alternative
embodiments of a ball member according to the present
invention;
[0100] FIG. 9 is a perspective view of a split outer housing
component of a valve according to an embodiment of the present
invention, wherein the split housing component is shown in a closed
configuration and coupled within a flowline;
[0101] FIG. 10 is a cross-sectional view of a valve assembly which
incorporates the split outer housing of FIG. 9;
[0102] FIG. 11 is a perspective view of a split outer housing
component of a valve according to an alternative embodiment of the
present invention, wherein the split housing component is shown in
an open configuration; and
[0103] FIG. 12 is a top elevational view of a ball valve shown
located within a riser, in accordance with a modified embodiment of
the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0104] A landing string assembly 10 is diagrammatically illustrated
in FIG. 1, shown in use within a riser 12 and extending between a
surface vessel 14 and a subsea wellhead assembly 16 which includes
a BOP 18 mounted on a wellhead 20. The use and functionality of
landing strings are well known in the art for through-riser
deployment of equipment, such as completion architecture, well
testing equipment, intervention tooling and the like into a subsea
well from a surface vessel.
[0105] When in a deployed configuration the landing string 10
extends through the riser 12 and into the BOP 18. While deployed
the landing string 10 provides many functions, including permitting
the safe deployment of wireline or coiled tubing equipment (not
shown) through the landing string and into the well, providing the
necessary primary well control barriers and permitting emergency
disconnect while isolating both the well and landing string 10.
[0106] Wireline or coiled tubing deployment may be facilitated via
a lubricator valve 22 which is located proximate the surface vessel
14.
[0107] Well control and isolation in the event of an emergency
disconnect is provided by a suite of valves, typically ball valves,
which are located at a lower end of the landing string 10 inside
the BOP. The valve suite includes a lower valve assembly called the
subsea test tree (SSTT) 24 which provides a safety barrier to
contain well pressure, and also functions to cut any wireline or
coiled tubing which extends through the landing string 10. The
valve suite also includes an upper valve assembly called the
retainer valve 26 which isolates the landing string contents and
can be used to vent trapped pressure from between the retainer
valve 26 and SSTT 24. A shear sub component 28 extends between the
retainer valve 26 and SSTT 24 which is capable of being sheared by
shear rams 30 of the BOP 18 if required. A slick joint 32 extends
below the SSTT 24 which facilitates engagement with BOP pipe rams
34.
[0108] The landing string 10 may include an interface arrangement
for interfacing with other oil filed equipment. For example, in the
present embodiment the landing string 10 includes a tubing hanger
36 at its lowermost end which engages with a corresponding tubing
hanger 38 provided in the wellhead 20. When the landing string 10
is fully deployed and the corresponding tubing hangers 36, 38 are
engaged, the weight of the lower string (such as a completion,
workover string or the like which extends into the well and thus
not illustrated) becomes supported through the wellhead 20.
However, during deployment of the lower string through the riser 12
all the weight and other forces associated with the lower string
must be entirely supported through the landing string 10.
Furthermore, when deployed a degree of tension is conventionally
applied to the landing string 10, for example to prevent adverse
compressive forces being applied, for example due to the weight of
the landing string 10, which can be significant in deep water. The
landing string 10 must thus be designed to accommodate significant
in-service loadings, such as the global tension and bending loads
from a supported lower string. Such in-service loadings, which may
also include valve actuation loading, internal and external
pressures and the like, must be accommodated across the various
valve assemblies, such as the SSTT 24. It is therefore necessary to
design the valve housings and appropriate end connections to be
capable of accommodating the global applied tension, bending loads,
valve actuation loading, pressures and the like.
[0109] A cross sectional view of a ball valve in accordance with an
embodiment of the present invention is shown in FIG. 2. The ball
valve may be provided for various functions, but for the purposes
of the present description the ball valve may define a SSTT 24 of
the landing string 10 shown in FIG. 1. It should be noted that
although the SSTT 24 is illustrated in FIG. 1 as a dual ball valve,
the arrangement shown in FIG. 2 is a single ball valve assembly for
purposes of clarity.
[0110] The ball valve 24 includes a housing, generally identified
by reference numeral 40 which is secured between the upper shear
sub component 28 and the lower slick joint 32. As such, the ball
valve 24 is installed in-line with the landing string 10 which can
be considered to be a fluid conduit system. The housing 40
accommodates a ball seat 42 and a ball member 44, wherein the ball
member 44 is rotatable about axis 46 to selectively close the ball
valve 24 and control flow through the landing string. In the
embodiment shown the ball member 44 is rotatable in the direction
of arrow 48 to close the ball valve 24. The ball seat 42 and ball
member 44 define respective through bores 50, 52 which when aligned
define a flow path through the valve 24 and when misaligned (as
shown in FIG. 2) prevent or restrict flow through the valve. When
the ball member 44 is closed a sealing area 54 is defined between
the ball seal 42 and ball member 44.
[0111] As will be discussed in further detail below, a leading edge
56 of the ball member 44 and/or ball seat 42 is configured to cut
through a body (not shown), such as wireline, coiled tubing or the
like which extends through the valve 24 and landing string 10 (FIG.
1) upon closure of the ball member 44.
[0112] As will also be discussed in further detail below, the
housing 40 comprises an outer housing 60 configured to be
mechanically secured in-line with the landing string 10 (FIG. 1),
and an inner housing 62 located within the outer housing 60 and
configured to contain pressure. The outer housing component 60
comprises a thin-walled, non-pressure containing cylindrical
portion 63 which extends between axially opposing end flange
connectors 64, 66 which are configured to be secured to flange
components 68, 70 of the shear sub 28 and slick joint 32,
respectively. In such an arrangement the outer housing 60 may be
defined as a structural housing. That is, the outer housing 60 may
be provided primarily to accommodate mechanical forces, such as
axial and bending forces, associated with the landing string 10 and
any supported lower string while providing minimal or no pressure
containment, for example of internal and/or external pressures.
[0113] The inner housing 62 comprises a generally cylindrical
portion or sleeve and does not include any mechanical connection to
the landing string 10 (FIG. 1). In such an arrangement the inner
housing 62 may be defined as a pressure housing. That is, the inner
housing 62 may be provided primarily for pressure containment, for
example of internal and/or external pressures, while providing
minimal or no contribution to accommodating mechanical loading
associated with the landing string 10 and/or supported lower
string.
[0114] This split role arrangement may permit each individual
housing 60, 62 to be designed and/or selected to meet more focussed
or specific operational requirements, providing a number of
advantages, such as permitting a reduction in the global wall
thickness of the housing which can increase the available internal
housing diameter.
[0115] The ball valve further includes an actuator assembly,
generally identified by reference numeral 72 for use in actuating
the ball member 44 to rotate relative to the ball seat 42 between
open and closed positions. In the present example the actuator
assembly 72 comprises a piston arrangement.
[0116] Various forms of ball member 44 and ball seat 42 may be
provided within the scope of the present invention. Some exemplary
embodiments are described below with reference to FIGS. 3 to 8.
[0117] Reference is initially made to FIGS. 3 and 4. FIG. 3 shows a
perspective view of a ball member, in this case identified by
reference numeral 44a, according to an exemplary embodiment of the
present invention, and FIG. 4 shown a cross-sectional view of the
ball member 44a of FIG. 3 in combination with an embodiment of a
ball seat, in this case identified by reference numeral 42a. Ball
member 44a and seat 42a have many features in common with ball
member 44 and seat 42 shown in FIG. 2 and as such like features
share like reference numerals, suffixed with the letter "a".
[0118] The ball member 44a defines a through bore 52a having a bore
edge 74, wherein a leading edge 56a defines a recessed cutting
region 76 which is configured to receive and cut through a body,
such as coiled tubing 78, shown in broken outline in FIG. 4
extending through the through bore 52a of the ball member 44a and a
through bore 50a of the ball seat 42a. That is, rotation of the
ball member 44a towards a closed position causes the coiled tubing
78 to become engaged between the edge of the ball seat 42a and the
recessed cutting region 76 of the ball member 44a, with further
rotation effecting cutting of the coiled tubing 78 primarily by a
shearing action. The ball member 44a includes a slotted region 80
which accommodates the lower portion of the coiled tubing 78 during
rotation of the ball member 44a.
[0119] The recessed cutting region 76 encroaches into the sealing
area 54a which is defined between the ball member 44a and ball seat
42a. In some embodiments the recessed cutting region may define a
relatively shallow recess such that sealing area 54a may not be
compromised. However, in other embodiments the ability to utilise a
thinner walled housing 40 by use of separate outer and inner
housings 60, 62 (having different roles, namely structural and
pressure containing) facilitates use of a larger ball member 44a
and ball seat 42a such that even with the presence of the recessed
cutting region 76 the sealing area 54a may be sufficiently large to
retain sealing integrity.
[0120] In the present embodiment the recessed cutting region 76 is
generally v-shaped. Such a v-shaped cutting region 76 is also shown
in FIG. 5 (reference to which is also made) which is a top
elevational view of the ball seat 42a and ball member 44a. Such a
profile defines two cutting edges 82, 84 which provide simultaneous
initial cutting into separate regions of the tubing 78. In this
way, during initial contact two points of cutting contact are
created which are offset from a central region of the tubing 78 and
which propagate together as cutting continues. This arrangement may
permit the force of cutting to be divided between the different
points of cutting contact provided by each cutting edge 82, 84,
assisting to prevent collapsing of the tubing 78 which the present
inventors have discovered can render cutting very difficult. Also,
this arrangement may require less torque through the ball member
44a to cut the tubing 78. Such reduced loading is anticipated to
reduce damage to the components of the ball valve which may assist
in preventing or reducing any damage to sealing regions, such as
sealing area 54a.
[0121] As illustrated most clearly in FIG. 5, in the present
embodiment, the leading edge 86 of the ball seat 42a does not
include any recessed region. However, in other embodiments, the
ball seat may also (or alternatively) include a recessed region.
Such an embodiment is illustrated in FIG. 6 which is a perspective
view, from below, of a ball seat 42b and ball member 44b which both
include recessed cutting regions 88, 90.
[0122] In the exemplary embodiments described above the recessed
cutting region is generally v-shaped. However, other arrangements
are possible. For example, a ball member 44c (or a corresponding
ball seat) may include a generally arcuate recessed region 92 as
shown in FIG. 7. Furthermore, in the exemplary embodiments
described above a single recessed cutting region is provided.
However, in other arrangements multiple recessed regions may be
provided. For example, a ball member 44c (or corresponding ball
seat) may include a pair of (or more) recessed regions 94 as shown
in FIG. 8. In such an embodiment a projection 96 may be defined
between each recessed region 94 which may function to pierce a
body, such as coiled tubing, to assist in initiating cutting while
minimising adverse collapse or the like. Such a projection may be
provided within embodiments including a single recess.
[0123] A perspective view of the ball valve 24 illustrated in FIG.
2 is shown in FIG. 9, reference to which is now made, along with
FIG. 10 which shows a further cross-sectional view of the ball
valve 24 with the ball member 44 and actuator 72 removed for
clarity.
[0124] As described above, the housing 40 of the valve 24 includes
an outer housing 60 and a separate inner housing 62, wherein the
outer housing 60 includes opposing flange connectors 64, 66 which
are secured to the respective flange components 68, 70 of the shear
sub 28 and slick joint 32. Each flange connection 64, 68 and 66, 70
is made via a plurality of bolts 100, wherein one or more of the
bolts 100 may be pre-tensioned to provide a degree of preloading
through the connections.
[0125] The inner housing 62 is axially retained between the flange
connectors 64, 66 of the outer housing 60. Furthermore, the ball
seat 42 is interposed between the upper flange connector 64 and the
upper end of the inner housing 62.
[0126] The inner housing 62 defines a unitary cylindrical
component, whereas the outer housing 60 is longitudinally split
along a line of separation 102 such that the outer housing 60 is
formed from two half segments 104, 106. Referring also to FIG. 11,
this split arrangement permits the outer housing 60 to be opened to
provide access to install, inspect, repair, replace or the like the
inner housing 62 and other components, such as the ball seat 42.
Splitting a housing of a valve is generally not attempted in the
art. However, the present invention permits the outer housing 60 to
be split as this does not need to provide any sealing or pressure
retaining function, which instead is provided by the unitary inner
housing 62.
[0127] The segments 104, 106 are hinged together along one side 108
and once closed may be retained closed upon connection of the
respective flange connectors 64, 66 to the flange components 68, 70
of the shear sub 28 and slick joint 32. Additionally, a
longitudinal connecting arrangement 110 is provided which
longitudinally secures the segments 104, 106 together when closed.
In an alternative embodiment no hinge connection may be provided
and instead both sides may be bolted to secure together the
different segments 104, 106. Providing such a longitudinal
connection arrangement 110 establishes appropriate hoop stiffness
within the outer housing 60 which may be required to resist bending
forces, for example.
[0128] The longitudinal connection arrangement 110 may be provided
in a number of forms. In this respect one such form is illustrated
in FIG. 9 (identified by reference numeral 110a), whereas an
alternative form is illustrated in FIG. 11 (identified by reference
numeral 110b).
[0129] The longitudinal connection arrangement 110a of FIG. 9
comprises a plurality of tangential-type bolts or cap screws 112
which extend through respective flange fingers or ribs 114 on one
housing segment 106 and engage threaded holes (not illustrated) in
the opposing housing segment 104. Each adjacent flange finger or
rib 114 is separated by a slotted region 116. This geometry assist
to redirect stress along this region of connection to, for example,
prevent high stresses at the locations of the cap screws 112 during
tensile loading.
[0130] The longitudinal connection arrangement 110b illustrated in
FIG. 11 comprises a plurality of interleaving components 118 on
each segment which are interleaved with each other when the segment
halves 104, 106 are closed. Each interleaving component 118
comprises an axially extending bore 120 which become aligned when
the segment halves 104, 106 are closed. An elongate connecting
member 122 is provided which is received within the aligned bores
120 to thus secure the segment halves 104, 106 together.
[0131] In the embodiments described above, such as with reference
to FIGS. 2 and 9 to 11, the outer housing defines a generally
cylindrical outer profile. However, in other embodiments a
non-cylindrical outer profile may be provided, as illustrated in
FIG. 12. In this embodiment a valve, generally identified by
reference numeral 124, includes a split outer housing 160 and a
unitary inner housing 162, in a similar manner to the embodiments
described above for similar reasons. However, in the present
embodiment the outer housing 160 defines a generally oval outer
profile. This arrangement permits other components, such as the
illustrated umbilical 123 to be accommodated between the valve 124
and an outer constraining component, such as a riser 12.
[0132] It should be understood that the embodiments described
herein are merely exemplary and that various modifications may be
made thereto without departing form the scope of the present
invention. For example, the disclosed valve embodiments are not
solely for use within a landing string, and may be used in many
other applications as would be understood by a person of skill in
the art. Furthermore, the multiple component housing arrangement
may also be used in combination with different valve types, and is
not limited solely for use in ball valve applications, although
defined and specific advantages do exist in such ball valve
applications.
* * * * *