U.S. patent application number 13/448284 was filed with the patent office on 2012-10-18 for assembly for actuating a downhole tool.
This patent application is currently assigned to Peak Completion Technologies, Inc.. Invention is credited to Raymond Hofman, William Sloane Muscroft.
Application Number | 20120261131 13/448284 |
Document ID | / |
Family ID | 47005542 |
Filed Date | 2012-10-18 |
United States Patent
Application |
20120261131 |
Kind Code |
A1 |
Hofman; Raymond ; et
al. |
October 18, 2012 |
Assembly for Actuating a Downhole Tool
Abstract
A valve seat assembly for actuating a connected downhole tool.
The connected downhole tool may be mechanically connected, such as
a sleeve positionable between flow ports through a housing, or
hydraulically connected, such as through establishing a fluid
communication path to the tool to cause actuation thereof. The
valve seat assembly generally has a seating element with an having
an inlet and an outlet; and a counting element configured to keep a
tally of the number times a first pressure at the inlet exceeds a
second pressure at the outlet by at least a pre-determined
amount.
Inventors: |
Hofman; Raymond; (Midland,
TX) ; Muscroft; William Sloane; (Midland,
TX) |
Assignee: |
Peak Completion Technologies,
Inc.
Midland
TX
|
Family ID: |
47005542 |
Appl. No.: |
13/448284 |
Filed: |
April 16, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61475333 |
Apr 14, 2011 |
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Current U.S.
Class: |
166/316 ;
166/331 |
Current CPC
Class: |
E21B 2200/06 20200501;
E21B 34/14 20130101 |
Class at
Publication: |
166/316 ;
166/331 |
International
Class: |
E21B 34/00 20060101
E21B034/00 |
Claims
1. A valve seat assembly for use in a well for oil, gas or other
hydrocarbons, said valve assembly comprising: a seating element
having an inlet and an outlet; and a counting element; wherein said
counting element is configured to keep a tally of the number times
a first pressure at the inlet exceeds a second pressure at the
outlet by at least a pre-determined amount.
2. The valve assembly of claim 1 further comprising an initiation
element configured to prevent said counting element from keeping
said tally until after such initiation element is actuated.
3. The valve assembly of claim 1 further comprising an activation
element, wherein said activation element is configured to actuate a
downhole tool when said tally reaches a desired number.
4. The valve assembly of claim 1 further comprising: an restrictor
element with a resilient portion having a first shape when no more
than a first pressure differential is applied across said engaging
element in a direction and a second shape when a second pressure
differential is applied across the restrictor element in the
direction; wherein said restrictor element is engagable with the
first seating element to substantially prevent fluid communication
through said sealing section when a pressure differential is
applied to the restrictor element that is less than the first
pressure differential; and wherein said restrictor element is
extrudable through said seating element without substantial
permanent deformation by applying at least the second pressure
differential.
5. The valve seat assembly of claim 1 wherein said seating element
comprises: a plurality of seat segments interconnected with at
least one elastomeric member, and wherein said seating element is
moveable between a first section of a housing, said first section
having a first inner diameter, and said housing further comprises a
second section downwell from said first section and having a second
inner diameter greater than said first inner diameter; and wherein
said first inner diameter is sized to prevent expansion of said
expandable sleeve when said expandable sleeve is positioned in said
first section, and said second inner diameter is sized to allow
expansion of said expandable sleeve when said expandable sleeve is
in said second section.
6. The valve seat assembly of claim 1 further comprising: an
annular sleeve having an inner surface with a diameter, a first
cylindrical outer surface, and a plurality of openings extending
between said inner surface and said first cylindrical outer
surface, wherein said annular sleeve further comprises a second
cylindrical outer surface having a different diameter than the
first cylindrical outer surface; wherein said seating element
comprises a first C-ring having a body with a seating surface,
opposing terminal ends, and an outer diameter extending from the
body, wherein the first C-ring is at least partially within the
inner surface of the sleeve; and a coil spring positioned around a
portion of the sleeve and in an annular space at least partially
defined by an annular body and the second cylindrical outer
surface.
7. The valve assembly of claim 1 wherein said counting element
comprises a slotted sleeve.
8. The valve assembly of claim 1 wherein said counting element
comprises a slotted sleeve having a plurality of neutral positions,
a plurality of shifted positions, and at least one actuated
position.
9. A valve assembly for use in a well for oil, gas or other
hydrocarbons, said valve assembly comprising: a seating element,
said seating element comprising an inlet and an outlet; and a
counting element; wherein said counting element is configured to
keep a tally of restrictor elements of a desired size range and
deformability range that pass through said seating element.
10. The valve assembly of claim 7 further comprising an initiation
element, said initiation element configured to prevent said
counting element from keeping said tally until after such
initiation element is actuated.
11. The valve seat assembly of claim 7 further comprising an
activation element, wherein said activation element is configured
to actuate a downhole tool when said tally reaches a desired
number.
12. A valve seat assembly for use in a well for oil, gas or other
hydrocarbons, said valve seat assembly comprising: a path for the
flow of fluids through the valve seat assembly; a seating element
configured to receive a restrictor element and thereby reduce or
eliminate the flow of fluids through the path; a guide element
comprising: a counting element configured to keep a tally of
restrictor elements having desired characteristics that pass
through said seating element, and an activation element, wherein
when said tally reaches a predetermined value, said activation
element is actuated and said valve assembly actuates a tool in
communication with said assembly.
13. The valve assembly of claim 10 wherein said counting element is
a slotted sleeve.
14. The valve assembly of claim 10 where said initiation element is
a shear pin.
15. A valve assembly for use with a downhole tool, said valve
assembly comprising: a seating element, said seating element
comprising an inlet and an outlet, and a guide element having a
counting member; wherein said seating element is configured to
engage a restrictor element and thereby reduce or prevent the flow
of fluid from said inlet to said outlet, said seating element is
engaged with said guide element such that said guide element is
configured to prevent actuation of said tool through a first cycle
of pressure increase and decrease; and said guide element is
configured to permit actuation of said tool during an activation
cycle, which occurs subsequent to said initiation cycle.
16. The valve assembly of claim 13 further comprising a plurality
of restrictor elements.
17. The valve assembly of claim 13 wherein said guide element is
configured to prevent actuation of said tool through a plurality of
indexing cycles.
18. A downhole tool for use in a production well having a tubing
string defining a flowpath, the downhole tool comprising: a ported
housing having a plurality of ports disposed radially therethrough;
a sleeve at least partially within said ported housing and moveable
between a first position and a second position, wherein in said
first position said sleeve is radially positioned between said
plurality of ports and said flowpath, said sleeve having an upper
end, an exterior surface, a slot formed in said exterior surface,
and an engagement surface having a first inner diameter; a guiding
member fixed relative to said housing and positionable within said
slot; and a compression spring positioned between said upper end of
said sleeve and said ported housing, said compression spring being
under compression when said sleeve is in said first position.
19. The downhole tool of claim 16 further comprising: a C-ring
having first and second terminal ends defining a split and a
plurality of radially-extending protrusions, said C-ring being
moveable between a compressed state, wherein the ends of the C-ring
are in contact to form a closed seat, and an uncompressed state;
wherein said sleeve has an interior surface, an exterior surface,
and a groove formed in said interior surface with a plurality of
openings extending between said interior and exterior surfaces,
said openings aligned to receive with said plurality of radially
extending protrusions; wherein said housing has a first inside
diameter and a second inside diameter that is larger than said
first inside diameter; wherein when said groove is positioned
within said first inside diameter, said protrusions hold said
C-ring in an at least substantially compressed state; and wherein
when said groove is positioned within said second inside diameter,
the C-ring is in an at least substantially uncompressed state.
20. The downhole tool of claim 17 further comprising: a propellant
volume; an annular portion with at least one pressure chamber
having an end positioned adjacent to said propellant volume and an
inlet providing a communication path to said flowpath; at least one
detonator assembly within said at least one pressure chamber
proximal to said end; at least one firing pin within said at least
one pressure chamber, said at least one firing pin having a first
end pressure isolated from a second end; a second section having a
plurality of flow ports defining a fluid communication path between
said flowpath and the exterior of the downhole tool; wherein said
sleeve is moveable between a first position and a second position,
wherein in said first position said sleeve assembly is between said
plurality of flow ports and said flowpath and between the inlet of
said at least one pressure chamber and said flowpath.
21. A system for producing hydrocarbons from a well wherein the
downhole tool of claim 16 is positioned as a bottom sub.
22. A valve seat assembly for use in a well for oil, gas or other
hydrocarbons, said valve assembly comprising: a seating element
having an inlet and an outlet; and a guide element; wherein said
guide element is configured to reflect the number times a first
pressure at the inlet exceeds a second pressure at the outlet by at
least a pre-determined amount.
23. The valve seat assembly of claim 22, said guide element further
comprises a timing element wherein said timing element causes
actuation of a tool when the number of times said first pressure
exceeds said second pressure by at least a pre-determined value
reaches a desired number.
24. The valve seat assembly of claim 22, said guide element further
comprises a timing element wherein said timing element allows
actuation of a tool when the number of times said first pressure
exceeds said second pressure by at least a pre-determined value
reaches a desired number.
25. An assembly for actuating a downhole tool in a production well
having a tubing string defining a flowpath, the assembly
comprising: a housing; an annular body at least partially within
said housing and moveable between a first position and a second
position, said annular body having an upper end, a lower end, an
exterior surface, a slot formed in said exterior surface; a guiding
member fixed relative to said housing and positionable within said
slot; and a spring positioned between said upper end of said
annular body and said housing, said spring being under compression
when said annular body is in said first position; wherein said slot
has a continuous path between a first and second end formed of
intersecting segments forming a repeated pattern of
circumferentially-aligned first positions and
circumferentially-aligned second positions positioned between said
first end and said second end, and wherein the first end intersects
one of said first positions and said second end is positioned
longitudinally between said first positions and said lower end of
said annular body.
26. The assembly of claim 25 wherein said annular body is a sleeve
having a seating element with an engagement surface having an inner
diameter sized to engage with a corresponding restrictor
element.
27. The assembly of claim 25 wherein said annular body is a slotted
member fixed relative to a seating element with an engagement
surface having an inner diameter sized to engage with a
corresponding restrictor element.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This original nonprovisional application claims the benefit
of U.S. provisional application Ser. No. 61/475,333 filed Apr. 14,
2011 and entitled "Downhole Tool and System for Producing
Hydrocarbons," which is incorporated by reference herein. This
application also claims the benefit of U.S. application Ser. No.
13/423,154, filed Mar. 16, 2012 and entitled "Downhole System and
Apparatus Incorporating Valve Assembly With Resilient Deformable
Engaging Element," and Ser. No. 13/423,158, filed Mar. 16, 2012 and
entitled "Multistage Production System Incorporating Downhole Tool
With Collapsible or Expandable C-Ring," both of which are
incorporated by reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
BACKGROUND
[0003] 1. Field of the Invention
[0004] The present invention relates to oil and natural gas
production. More specifically, to systems, tools, and methods used
in fracturing and/or producing hydrocarbons in one or more stages
in a hydrocarbon-producing well.
[0005] 2. Description of the Related Art
[0006] In hydrocarbon wells, fracturing (or "fracing") is a
technique used by well operators to create and/or extend a fracture
from the wellbore deeper into the surrounding formation, thus
increasing the surface area for formation fluids to flow into the
well. Fracing can be accomplished by either injecting fluids into
the formation at high pressure (hydraulic fracturing) or injecting
fluids laced with round granular material (proppant fracturing)
into the formation.
[0007] Fracing multiple-stage production wells requires selective
actuation of downhole tools, such as fracing valves, to control
fluid flow from the tubing string to the formation. For example,
U.S. Published Application No. 2008/0302538, entitled Cemented Open
Hole Selective Fracing System and which is incorporated by
reference herein, describes embodiments for selectively actuating a
fracing sleeve that incorporates a shifting tool. The tool is run
into the tubing string and engages with a profile within the
interior of the valve. An inner sleeve may then be moved to an open
position to allow fracing or to a closed position to prevent fluid
flow to or from the formation.
[0008] That same application describes a system using multiple
ball-and-seat tools, each having a differently-sized ball seat and
corresponding ball. Ball-and-seat systems address some of the
drawbacks of shifting tools because they do not require running
such shifting tools thousands of feet into the tubing string.
Ball-and-seat systems can be designed to allow a one-quarter inch
difference between sleeves and the inner diameters of the seats of
the valves within the string. For example, in a 4.5-inch liner,
balls from 1.25-inches in diameter to 3.5-inches in diameters can
be dropped in one-quarter inch or one-eighth inch increments, with
the smallest ball seat positioned in the last valve in the tubing
string. This, however, can limit the number of valves that can be
used in a given tubing string because in these systems each ball is
designed to actuate a single valve and the size of the liner may
limit the number of valves with differently-sized ball seats.
BRIEF SUMMARY
[0009] The present invention increases system effectiveness and
reduces mechanical risk, thereby increasing system reliability
while lowering cost. Operators need not be concerned about
impacting the shifting ball into a seat at too high of a rate or
pressure which may lead in some cases to a failure of the ball or
sleeve.
[0010] The present invention contemplates a valve seat assembly for
actuating a connected downhole tool. The connected downhole tool
may be mechanically connected, such as a sleeve positionable
between flow ports through a housing, or hydraulically connected,
such as through establishing a fluid communication path to the tool
to cause actuation thereof. The valve seat assembly generally has a
seating element with an having an inlet and an outlet; and a
counting element configured to keep a tally of the number times a
first pressure at the inlet exceeds a second pressure at the outlet
by at least a pre-determined amount.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0011] FIG. 1 is a sectional side elevation of a preferred
embodiment of the apparatus of the present invention in a neutral
state.
[0012] FIG. 1A is an enlarged view of window 1A of FIG. 1.
[0013] FIGS. 2A and 2B are isometric front and rear views of the
slotted member shown in FIG. 1.
[0014] FIG. 2C shows the footprint of the slot formed in the
exterior surface of the slotted member shown in FIGS. 2A and
2B.
[0015] FIG. 3 is intentionally omitted.
[0016] FIG. 4 is a side sectional elevation of the embodiment shown
in FIG. 1 in a shifted state.
[0017] FIG. 4A is an enlarged view of window 4A of FIG. 4.
[0018] FIG. 5 is a side sectional elevation of the embodiment shown
in FIG. 1 in an actuated state.
[0019] FIG. 5A is an enlarged view of window 5A of FIG. 5.
[0020] FIG. 6 is a side elevation of a system incorporating
multiple ported sleeves of the preferred embodiment shown in FIG.
1.
[0021] FIG. 7 is a sectional elevation of a pressure chamber and
firing pin of a second embodiment of the invention.
[0022] FIG. 8 is a sectional elevation of the firing assembly and
pressure chamber shown in FIG. 7 wherein the firing pin has been
released and has impacted the primer.
[0023] FIG. 9 shows components of yet another embodiment of a valve
assembly that comprises a C-ring.
[0024] FIG. 10 is a front elevation for the C-ring of FIG. 9
[0025] FIG. 11 is a sectional view through line 11-11 of FIG.
9.
[0026] FIG. 12 shows the embodiment of FIG. 9 with the sleeve and
valve assembly in a shifted position.
[0027] FIG. 13 is a sectional view through line 13-13 of FIG.
12.
[0028] FIG. 14 shows the embodiment of FIG. 9 with the sleeve and
valve assembly in an actuated position.
DETAILED DESCRIPTION
[0029] When used with reference to the figures, unless otherwise
specified, the terms "upwell," "above," "top," "upper," "downwell,"
"below," "bottom," "lower," and like terms are used relative to the
direction of normal production through the tool and wellbore. Thus,
normal production of hydrocarbons results in migration through the
wellbore and production string from the downwell to upwell
direction without regard to whether the tubing string is disposed
in a vertical wellbore, a horizontal wellbore, or some combination
of both. Similarly, during the fracing process, fracing fluids move
from the surface in the downwell direction to the portion of the
tubing string within the formation.
[0030] FIG. 1 depicts a valve seat assembly 22 in which the tool to
be actuated is a ported sleeve. A tubing string section 26 provides
a fluid communication path between the ported sleeve assembly 22
and other downhole tools or accessories.
[0031] The ported sleeve assembly 22 can transition between three
states: (i) a neutral position, which is shown in FIG. 1; (ii) a
"shifted" position, as shown in and described with reference to
FIG. 4; and (iii) an "actuated" position, as shown in and described
with reference to FIG. 5. When used with reference to a
normally-closed ported sleeve assembly, "actuated" means that the
ports are opened to allow radial flow of fluid therethrough.
[0032] The ported sleeve assembly 22 comprises a top connection 28
threaded to a housing assembly 30 that includes a spring housing
32, a seal housing 34 having an annular upper end 36, and a ported
housing 40. A plurality of radially-aligned ports 42 is disposed
through the ported housing 40 to provide a fluid communication path
between the interior of the ported sleeve assembly 22 and the
surrounding formation.
[0033] A sleeve 44 is nested and moveable longitudinally within the
housing assembly 30. The sleeve 44 comprises a spring mandrel 46
having an annular shoulder 48 located at the upper end of the
sleeve 44, and an upper seal mandrel 50 having an annular lower end
51. A compression spring 62 is positioned within an annular volume
defined by the annular shoulder 48 and the annular upper end 36 of
the seal housing 34. In the neutral position shown in FIG. 1, the
compression spring 62 is under approximately three-hundred pounds
of compression.
[0034] A plurality of circumferentially-aligned initiation elements
(e.g., shear pins) 41 extend through the ported housing 40 and
engage the sleeve 44. The initiation elements are frangible upon
application of a predetermined pressure by the sleeve 44.
[0035] The sleeve 44 further comprises a lower seal mandrel 52
having an annular middle shoulder 53, and an annular slotted member
54 positioned around the lower seal mandrel 52 and fixed
longitudinally between the lower end 51 of the upper seal mandrel
50 and the middle shoulder 53. The slotted member 54 fits snugly
around the lower seal mandrel 52, but is freely rotatable
thereabout. The sleeve 44 incorporates a valve seat assembly that
has a seating element in the form of an annular inner engagement
surface 39 that will seal with an appropriately sized and shaped
restrictor element (e.g., wiper ball or dart), as will be described
infra. The engagement surface 39 comprises a first and second
opposing openings 39', 39''.
[0036] As shown in FIG. 1A, the valve seat assembly includes a
guide element that has a counting element. The counting element
includes a guiding member, such as a torque pin 56, and a slot 58
formed in the exterior surface 60 of the slotted member 54. The
torque pin 56 is fixed relative to, and extends through, the ported
housing 40.
[0037] The torque pin 56 is positioned within the slot 58. FIGS.
2A-2C show the slotted member 54 and the slot 58 in more detail.
The slot 58 is a continuous path formed of intersecting discrete,
straight path segments, the path extending radially around and
formed in the exterior surface 60 of the slotted member 54. The
intersections of the slot segments of the slot 58 form a repeated
pattern of thirteen neutral positions 55a-55m and thirteen shifted
positions 57a-57m positioned between a first end 59 and a second
end 61. The first end 59 of the slot 58 terminates in the first
neutral position 55a. The second end 61 of the slot 58 terminates
with an actuated position 63 positioned downwell of the neutral
positions 55a-55m.
[0038] The slot 58 is shaped so that when the torque pin 56 is in a
neutral position and the slotted member 54 moves downwell relative
to the ported housing 40 (in direction Ddw), the torque pin 56
moves, relative to the slotted member 54, toward the adjacent
shifted position. For example, when the torque pin 56 is in the
first neutral position 55a and the slotted member 54 moves in
direction Ddw, the torque pin 56 travels along the slot 58 to the
first shifted position 57a, where further downwell movement of the
slotted member 54 is impeded. When the torque pin 56 is in a
shifted position, such as the first shifted position 57a, and the
slotted member 54 moves upwell in direction Duw, the torque pin 56
travels toward the next adjacent neutral position, which is the
second neutral position 55b, or, if the torque pin 56 is at the
thirteenth shifted position 57m, to the actuated position 63.
[0039] Operation of the embodiment 20 is initially described with
reference to FIG. 1. During installation, the embodiment 20 is
positioned in a wellbore with the torque pin 56 positioned at the
first end 59 of the slot 58 (see FIG. 2C), which is in the first
neutral position 55a. In this neutral state or position, the sleeve
44 is positioned radially between the plurality of ports 42 and the
flowpath to prevent fluid flow to and from the surrounding
formation.
[0040] As shown in FIG. 4, to shift the sleeve assembly 22 from a
neutral position to a shifted position, the well operator pumps a
restrictor element (e.g., ball) 80 downwell to the sleeve assembly
22. In the illustrated embodiment, the ball 80 is larger than the
inner diameter of the seating element 39 that is the engagement
surface of the sleeve 44. The ball 80 passes through the first
opening 39', which functions as an inlet, and seals to the
engagement surface 39 of the sleeve 44, thus creating a friction
pressure against it. Although the expansive force of the
compression spring 62 resists downwell movement of the sleeve 44,
when the pressure differential across the ball 80 exceeds a first
pressure differential, the expansive force of the compression
spring 62 is overcome and the sleeve 44 moves to the second
position shown in FIG. 4, thus positioning the torque pin 56 in the
next shifted position of the slotted member 54, depending on the
position of the torque pin 56 within the slot 58 prior to shifting.
In this manner, the torque pin 56 and slot 58 operate to keep a
tally of the number times the pressure differential created across
the ball between the inlet 39' and the outlet 39'' exceeds a first
pressure differential by at least a pre-determined amount. Because
slot 58 contains a predetermined number of slot positions the
slotted member 54, torque pin 56 and slot 58 can be used to
effectively count the number of balls that are extruded through the
sleeve assembly 22 or the number of times a pressure differential
is created between the inlet and the outlet exceeds a first
pressure differential by at least a pre-determined amount. The
positioning of torque pin 56 and slot 58 in slotted member 54
indexes the number of times the sleeve assembly 22 is shifted and
tabulates the number using the positioning of torque pin 56 and
slot 58 to enable a plurality of stages using multiple sleeve
assemblies to be used because particular sleeve assemblies can be
actuated with precision and at predetermined times or stages.
[0041] After the sleeve 44 has shifted, the continued pressure
differential will extrude the ball 80 past the engagement surface
39 and through the sleeve 44. The compression spring 62 will
thereafter expand to return the sleeve 44 to either a neutral or
the actuated position, depending on the position of the torque pin
56 within the slot 58 (see FIG. 2C).
[0042] As shown in FIG. 2C, the sequence described above is
repeatable for the sleeve 44 until the torque pin 56 is positioned
in the final neutral position 55m of the upper slot 58m.
Thereafter, the next ball passing through the sleeve 44 will move
sleeve 44 and position the torque pin 56 to move to the final
shifted position 57m of the slot 58. After the ball passes through
the sleeve 44 as described supra, the compression spring 62 will
urge the spring return 46 upwell until the torque pin 56 is
positioned in the actuated position 63. While the embodiments
illustrated in the figures show 13 neutral and shifted positions,
any plurality of neutral and shifted positions are contemplated in
the scope of the present invention. Further, the number of neutral
and shifted positions are preferably the same, but differing
numbers of neutral and shifted positions may be included in
embodiments encompassed by the claimed invention.
[0043] As shown in FIG. 5, when the first torque pin 58 is located
in the actuated position 63 of the slot 58, the sleeve 44 is in a
second position upwell of the ports 42, thereby permitting fluid
flow into the surrounding formation from the flowpath. In this
state, the compression spring 62 is under minimal, if any,
compression.
[0044] Although the sleeve assembly 22 as described above requires
thirteen cycles to actuate the sleeve 44 to the second position if
the torque pin 56 is initially positioned at the first end 59 of
the slot 58, the number of shifting cycles until actuation may be
reduced by positioning the sleeve assembly 22 in the wellbore with
the torque pins 56 positioned in one of the intermediate neutral
slot positions 55b-55m. For example, the embodiment 20 may be
preset to require only four shifting cycles by setting the torque
pin 58 to the tenth neutral position 55j prior to installation in
the tubing string. Thus, passage of the fourth wiper ball will
actuate the sleeve assembly 44 to the second position shown in FIG.
5. Moreover, slotted member 54 is not limited to thirteen slot
positions but rather the number of slots can be increased or
decreased.
[0045] FIG. 6 shows a system comprising three ported sleeve
assemblies 22a-22c installed in a formation production well drilled
in a hydrocarbon producing formation 100 that has three stages
100a-100c. Each of the ported sleeve assemblies 22a-22c is
configured to require a different number of shifting cycles prior
to actuating: the lower sleeve assembly 22c is located in the lower
stage 100c and is set to actuate after one shifting cycle (i.e.,
the guiding member is initially positioned in neutral position 55m
of FIG. 2C); the middle sleeve assembly 22b is located in the
middle stage 100b and is set to actuate after two shifting cycles
(i.e., the guiding member is initially positioned in neutral
position 55l); and the upper sleeve assembly 22a is located in the
upper stage 100a and is set to actuate after three shifting cycles
(i.e., the guiding member is initially positioned in neutral
position 55k).
[0046] To fracture the surrounding formation 100, a first
restrictor element is moved through the tubing string and
assemblies 22a-22c as described supra. Because the lower assembly
22c is set to only require (i.e., "count") one shifting cycle for
actuation, the lower assembly 22c is opened to permit fluid flow
into the surrounding formation 100. When a second restrictor
element is passed through the tubing string, the middle ported
assembly 22b is opened. The area adjacent to the middle assembly
22b may thereafter be fraced. When a third restrictor element is
passed through the tubing string, the upper ported sleeve assembly
22a is opened. The area adjacent to the upper sleeve assembly 22a
may thereafter be fraced. After fracturing, the well operator can
produce hydrocarbons through the assemblies 22a-22c and downwell of
the deepest assembly 22c
[0047] The present invention also increases system effectiveness
and reduces mechanical risk, thereby increasing system reliability
while lowering cost. Operators need not be concerned about
impacting the shifting ball into a seat at too high of a rate or
pressure which may lead in some cases to a failure of the ball or
sleeve.
[0048] In one embodiment of a system incorporating the sleeve
assembly, a ported sleeve assembly is positioned as a bottom sub,
or "toe sub," in a tubing string having a cemented liner. The
assembly is cemented into place within the wellbore. Upon actuation
of the ported sleeve assembly following the cycling of pressure
through the tool as described supra, pressure may be increased to
crack the cement sheath and establish fluid contact to the
formation.
[0049] In FIGS. 1-6, a valve seat assembly is incorporated into a
ported sleeve assembly and described with reference to actuation of
a ported sleeve for use in fracturing application. The valve seat
assembly described supra, however, may be used to actuate any
number of downhole tools, including flapper valves, stimulation
devices, packers, and the like.
[0050] FIG. 7, for example, shows a section of a sleeve assembly as
described supra that further comprises propellant stimulation
components. More specifically, FIG. 7 is a side sectional view of a
detonator assembly 158 and a firing pin 190 positioned with a
pressure chamber 154 formed in the assembly. One or more such
pressure chambers 154 may be positioned within the tool.
[0051] The firing pin 190 is within pressure chamber 154 proximal
to an inlet 155, and is retained in position by a firing pin
locking key 176 engaged with a retention groove 200
circumferentially disposed around the firing pin 190. A first end
188 of the firing pin 190 is pressure isolated from a second end
189 with a sealing ring 202. The inlet 155 of each chamber 154
provides a fluid communication path to the flowpath.
[0052] The detonator assembly includes a primer 192, primer case
194, shaped charge 196, and an isolation bulkhead 198. The primer
192 is spaced above the firing pin 190 within the primer case 194.
The shaped charge 196 is positioned above and adjacent to the
primer case 194. The isolation bulkhead 198 is positioned adjacent
the shaped charge 194 and proximal to the propellant volume 146. In
this position, detonation of the shaped charge will cause
corresponding ignition of the propellant volume 146.
[0053] Downwell movement of the sleeve 44 causes hydraulic
actuation of the firing pin 190 by allowing the firing pin locking
key 176 to radially contract into a groove formed into the exterior
surface of the sleeve 44. This contraction causes the firing pin
locking key 176 to disengage from the firing pin 190.
[0054] Pressure thereafter communicated into the pressure chamber
154 causes the firing pin 190 to move upwell because of the
pressure differential above and below the sealing ring 202. In
other words, because pressure upwell of the sealing element 202 is
atmospheric, hydraulic pressure below the sealing element applies a
hydraulic force on the second end 189 of the firing pin 190
resulting in upwell movement. While the tool illustrated by the
figures shows a sleeve for use in connection with a ported housing,
such ported housing is not a required element of the claimed
invention. A sleeve of any size, type or shape may be used provided
that it, by its relationship with a valve seat, allows activation
of the propellant stimulation components in response to a pressure
drop across the valve seat.
[0055] FIG. 8 shows the detonator assembly 158 with the pressure
chamber 154 after the firing pin locking key 176 has released the
firing pin 190 and at the point of contact of the firing pin 190
with the primer 192. The sealing ring 202 between the first end 188
and second end 189 of the firing pin 190 isolates pressure in the
pressure chamber 154 upwell of the sealing ring 202 from the
pressure in the flowpath. After ports 174 are aligned with the
inlet 155, pressure within the flowpath is communicated through the
ports 174 into the pressure chamber 154 at a position below the
sealing element 202, resulting in a pressure differential that
moves the firing pin 190 upwell to contact and detonate the primer
192. Detonation of the primer 192 is contained by the case 194 and
causes detonation of the adjacent shaped charge 196, which
transfers explosive energy to the propellant volume 146, causing
ignition thereof. The explosive energy is directed radially
outwardly in the form of pressure waves and into the surrounding
formation. By use of the valve seat assembly described herein,
detonation may be timed to actuate following a preset number of
pressure increases resulting from seating, and subsequent passage,
of a restrictor element between the first and second openings 39',
39'' of the engagement surface 39.
[0056] FIG. 9 shows a tool 320 actuatable by a valve seat assembly
having a slotted sleeve 348 and a torque pin 400. The tool 320
comprises a housing 322 connected to a bottom connection 324 at a
threaded section 326. The housing 322 has a plurality of
radially-oriented, circumferentially-aligned ports 328 providing
communication paths to and from the exterior of the tool 320.
[0057] The housing 322 has a first cylindrical inner surface 330
having a first inner diameter, a second cylindrical inner surface
332 located downwell of the first inner surface 330 and having a
second inner diameter that is greater than the first inner
diameter, and a third cylindrical inner surface 334 having a third
inner diameter that is greater than the second cylindrical inner
surface 332. The first inner surface 330 is longitudinally adjacent
to the second inner surface 332, forming a downwell-facing shoulder
having an annular shoulder surface 338. The second and third inner
surfaces 332, 334 are separated by a partially-conical surface
340.
[0058] The tool 320 comprises an annular sleeve 348 nested radially
within the housing 322 and positioned downwell of the shoulder 338.
The sleeve 348 has an upper outer surface 350 with a first outer
diameter and a second outer surface 352 with a second outer
diameter less than the first inner diameter. The first outer
surface 350 and second outer surface 352 are separated by an
annular shoulder surface 354. The sleeve 348 further comprises a
cylindrical inner surface 356 that extends between annular upper
and lower end surfaces 358, 360 of the sleeve 348.
[0059] The tool 320 may further comprise a guide element to
position the seating element of the valve assembly at the desired
location. The guide element in the embodiment of FIG. 9 is a spring
364 residing in an annular spring return space 362. The annular
spring return space 362 is partially defined by the second outer
surface 352 of the sleeve 348 and the third inner surface 334 of
the housing 322. The spring return space 362 is further defined by
the upper end surface 347 of the bottom connection 324, the
partially-conical surface 340 of the housing 322, and the shoulder
surface 354 and first outer surface 350 of the sleeve 348.
[0060] In the embodiment illustrated by the figures, a C-ring 370
is positioned within the annular sleeve 348 between the upper end
surface 358 and the shoulder surface 354. The C-ring 370 fits into
a groove formed in the inner surface 356 of the shifting sleeve
348. The groove is sufficiently deep to allow the C-ring seating
surface to expand to the desired maximum diameter. In some
embodiments, the desired maximum diameter may be as large as or
larger than the inner diameter of the shifting sleeve. Those of
skill in the art will appreciate that, in embodiments in which the
C-ring 370 activates a sleeve or other valve assembly, the C-ring
70 may be positioned at any point along the sleeve or tool, or
above or below the sleeve, provided that the C-ring 370 and the
sleeve 348 or other tool are connected such that sufficient
pressure applied to the C-ring 370 will slide the sleeve in
relation to the inner housing or otherwise activate the tool.
[0061] The C-ring 370 has an inner surface 374 an outer surface 376
defining the outer perimeter of the C-ring 370, and a seating
surface 372 engagable with a restrictor element (e.g., a ball or
dart) having a corresponding size. In the illustrated embodiment,
the C-ring 370 is held in a radially compressed state by the first
inner surface 350 of the housing 322.
[0062] The valve seat assembly includes a guide element that has a
counting element, a timing element, an indexing element or other
device for recording or reflecting the restrictor elements which
engage and pass through the assembly or for recording or reflecting
the pressure drops which occur across the valve seat which exceed a
pre-determined value. In certain embodiments, such as the
embodiment illustrated in FIG. 9, a counting element includes a
guiding member, such as a torque pin 400, and a slot 402 formed in
the exterior surface 361 of the sleeve 348. The torque pin 400 is
fixed relative to, and extends through, the housing 322 and bottom
connection 324.
[0063] In FIG. 9, the torque pin 400 is positioned in a "neutral"
position of the slot 402, which is identical to the slot shown in
and described with reference to FIGS. 2A-2C and is a continuous
path formed of intersecting discrete, straight path segments. The
slot 402 extends radially around, and is formed in, the exterior
surface 361 of the sleeve 348. The guiding element is positioned in
a neutral position of the slot 402, with the upper end 358 of the
sleeve 348 positioned below the ports 28.
[0064] As indicated with reference to FIGS. 1-6, the sleeve 348 can
transition between three positions: (i) a neutral position, which
is shown in FIG. 9; (ii) a "shifted" position, as shown in and
described with reference to FIG. 12; and (iii) an "actuated"
position, as shown in and described with reference to FIG. 14. When
used with reference to a normally-open ported sleeve assembly,
"actuated" means that the ports are closed to inhibit radial flow
of fluid therethrough.
[0065] As those of skill in the art will appreciate, the position
of torque pin 400 within the slotted sleeve 348 reflects the number
of pressure drops of a pre-determined value which must occur across
the C-ring 370, (e.g. the valve seat) before a subsequent pressure
drop of will cause actuation of the associated tool. In practice,
such pressure drops are created by engaging the C-ring 370, or
other valve seat, with a restrictor element. The valve seat thereby
"counts" the number of restrictor elements passing the valve seat
by indexing from one neutral position to the next. Such counting
occurs as a restrictor element engages with the valve seat, enables
formation of the required pressure drop, the sleeve moves to the
next shifted position, the restrictor element releases from the
valve seat, and the sleeve moves, by force of the spring, to the
next neutral position. This cycle is repeated with subsequent
restrictor elements configured to create the necessary pressure
drop across the valve seat (e.g. restrictor elements of the
appropriate size and material). In this fashion, the guide element
affects the actuation of the tool by indexing from neutral position
to neutral position and thereby, in conjunction with the seating
element and restrictor element, controls the timing for actuation
of the tool.
[0066] FIG. 10 shows a front elevation of one embodiment of the
C-ring 370 in a normal uncompressed state. In this embodiment, the
outer surface 376 of the C-ring 370 is castellated with a plurality
of radial protrusions 378, said radial protrusions defining the
outer diameter of the C-ring 370. The circumference of the outer
surface of the C-ring 370 may be larger than the circumference of
inner surface 356 of the sleeve 348. The C-ring 370 has a machined
slot 380 forming terminal ends 382. The slot 380 shown in the
illustrative figures is within a protrusion 378, but the slot 380
may be formed at any point along the C-ring 370 and does not have
to be formed in a protrusion 378.
[0067] Referring to FIG. 11, each of the radial protrusions 378 of
the illustrated C-ring 370 is aligned with and extends through an
opening 384 in the sleeve 348 between the first outer surface 350
and the inner surface 356. When the C-ring 370 is upwell of the
partially-conical shoulder 340 of the housing 322, the C-ring 370
has the operating diameter shown in FIG. 11 and terminal ends 382
of C-ring 370 are in contact to form the seat defined by the
seating surface 372. An associated restrictor element may
thereafter seat against the seating surface 372 and a pressure
differential created across the restrictor element to move the
sleeve 348 in the downwell direction.
[0068] FIGS. 12-13 show the tool 320 with the sleeve 348 in a
shifted position, which is downwell of the position shown in FIG.
9. The coil spring 364 is under compression between the sleeve 348
and the bottom connection 324, with the upper end coil 366 of the
spring 364 in contact with the sleeve shoulder 354 and the spring
lower end 368 is in contact with the upper end surface 347 of the
bottom connection 324. In this position, the spring 364 exerts an
expansive force to urge the sleeve 348 in the upwell direction
relative to the bottom connection 324. The torque pin 400 is
positioned in a "shifted" position of the slot 402.
[0069] Referring to FIG. 13, the C-ring 370 is positioned adjacent
to the second inner surface 334. Because the second inner surface
334 has a larger diameter than the first inner surface 332, the
C-ring 370 radially expands towards its uncompressed shape shown in
FIG. 10. The protrusions 378 extend past the outer surface 350 of
the sleeve 348, opening the seating surface 372 and allowing the
associated restrictor element to pass through the C-ring 370, after
which the spring 364 pushes against the sleeve shoulder 354 to move
the sleeve 348 upwell.
[0070] FIG. 14 shows the sleeve 348 in an actuated position in
which fluid flow to the exterior of the tool 320 is inhibited by
the sleeve 348. The C-ring 370 is held in a closed state by the
second inner surface 332 of the housing 322. The torque pin 400 is
positioned in an "actuated" position of the slot 402. In one
alternative embodiment, the C-ring 370 may be adjacent to an
additional inner surface, not shown, which is sufficiently large to
allow the C-ring to expand into its uncompressed state. Further,
the claimed invention also encompasses embodiments in which the
valve assembly is moved to the actuated position by downwell
movement past the shifted position. In such an embodiment, a device
which locks the valve assembly in the actuated position may be
desirable in order to hold the valve assembly in place against the
force of the spring 364.
[0071] In some embodiments, a retaining element, not shown, may be
placed in the sleeve to define this intermediate position, such
retaining element being set such that it stops movement of the
C-ring 370 and sleeve up to a first pressure, but allows movement
of the C-ring 370 at a second pressure. Those of skill in the art
will appreciate that many retaining elements such as a shear ring,
shear pins, or other device may be used in conjunction with the
valve assemblies described herein. Further, mechanisms, assemblies,
methods or devices other than a retaining element may be used for
defining the intermediate third position in a valve assembly and
any such method or element is within the scope of the valve
assemblies contemplated herein.
[0072] Yet another embodiment contemplates a seating element
separately attachable to the interior surface of a sleeve and
operable with a resilient restrictor element, such as the valve
seat assembly shown in U.S. application Ser. No. 13/423,154, filed
Mar. 16, 2012 and entitled "Downhole System and Apparatus
Incorporating Valve Assembly With Resilient Deformable Engaging
Element," and which is incorporated by reference. In this
embodiment, the restrictor element has a resilient portion with a
first shape when no more than a first pressure differential is
applied across said restrictor element in a direction and a second
shape when a second pressure differential is applied across the
restrictor element in the same direction. The restrictor element is
engagable with the seating element to substantially prevent fluid
communication through said sealing section when a pressure
differential is applied to the restrictor element that is less than
the first pressure differential. The restrictor element is
extrudable through said seating element without substantial
permanent deformation by applying at least a second pressure
differential.
[0073] According to another embodiment of the invention, the
seating element may comprise a plurality of seat segments
interconnected with at least one elastomeric member, as disclosed
in U.S. application Ser. No. 12/702,169, filed Feb. 28, 2010 and
entitled "Downhole Tool With Expandable Seat," which is
incorporated by reference herein. In this alternative embodiment,
the seating element is moveable between a first section of a
housing, said first section having a first inner diameter. The
housing has a second section downwell from said first section and
having a second inner diameter greater than said first inner
diameter. The first inner diameter is sized to prevent expansion of
the seating element when the seating element is positioned in said
first section, whereas the second inner diameter is sized to allow
expansion of the expandable seat when in the second position. Any
other valve seat-restrictor element combination is within the scope
of the claimed invention provided such combination allows the
creation of a desired pressure drop across the valve seat, the
release of the restrictor element past the valve seat, and the
restrictor element is substantially undamaged or otherwise not
deformed such that it can form a fluid seal with a subsequently
engaged valve seat.
[0074] The apparatus and systems are described in terms of
embodiments in which a specific system and method are described.
Those skilled in the art will recognize that alternative
embodiments of such system, and alternative applications of the
method, can be used. Other aspects and advantages may be obtained
from a study of this disclosure and the drawings, along with the
appended claims. Moreover, the recited order of the steps of the
method described herein is not meant to limit the order in which
those steps may be performed.
* * * * *