U.S. patent application number 13/528907 was filed with the patent office on 2013-12-26 for downhole debris removal tool and methods of using same.
The applicant listed for this patent is Gregory L. Hern, Yang Xu, YING QING XU. Invention is credited to Gregory L. Hern, Yang Xu, YING QING XU.
Application Number | 20130341027 13/528907 |
Document ID | / |
Family ID | 49773436 |
Filed Date | 2013-12-26 |
United States Patent
Application |
20130341027 |
Kind Code |
A1 |
XU; YING QING ; et
al. |
December 26, 2013 |
DOWNHOLE DEBRIS REMOVAL TOOL AND METHODS OF USING SAME
Abstract
A downhole tool for removing debris from a wellbore comprises a
screen member, an incoming fluid accelerator, and a cavity for
capturing debris. The incoming fluid accelerator is disposed above
the screen and accelerates the flow of an incoming fluid through
the accelerator and into a screen bore. The incoming fluid then
exits the bottom of the tool, mixes with wellbore fluid containing
debris to form a combination fluid that is transported upward
within the wellbore annulus. A pressure differential between the
incoming fluid flowing within the screen bore and the wellbore
annulus pulls the combination fluid containing the debris into the
cavity where the debris is captured. Fluid and/or debris not
blocked by the screen flows through the screen into the screen bore
to be circulated downward and out of the tool where it can pick up
additional debris for capture.
Inventors: |
XU; YING QING; (Tomball,
TX) ; Hern; Gregory L.; (Porter, TX) ; Xu;
Yang; (Houston, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
XU; YING QING
Hern; Gregory L.
Xu; Yang |
Tomball
Porter
Houston |
TX
TX
TX |
US
US
US |
|
|
Family ID: |
49773436 |
Appl. No.: |
13/528907 |
Filed: |
June 21, 2012 |
Current U.S.
Class: |
166/301 ;
166/99 |
Current CPC
Class: |
E21B 27/005
20130101 |
Class at
Publication: |
166/301 ;
166/99 |
International
Class: |
E21B 31/08 20060101
E21B031/08; E21B 31/00 20060101 E21B031/00 |
Claims
1. A downhole tool for capturing debris within a wellbore, the
downhole tool comprising: a screen member having a screen upper
end, a screen lower end, a screen outer wall surface, a screen
inner wall surface defining a screen bore, and at least one screen
aperture in fluid communication with the screen inner wall surface
and the screen outer wall surface; an incoming fluid flow
accelerator disposed above the screen member, the incoming fluid
flow accelerator comprising an incoming fluid flow accelerator bore
through which an incoming fluid flows toward the screen bore, the
incoming fluid flow accelerator bore being in fluid communication
with the screen bore such that an incoming fluid flowing out of the
incoming fluid flow accelerator bore and into the screen bore
creates a pressure differential across at least one of the at least
one apertures; and a shroud disposed around a portion of the screen
member, the shroud having an opening disposed toward an upper end
of the shroud and a closed lower end to define a cavity.
2. The downhole tool of claim 1, wherein the incoming fluid flow
accelerator further comprises at least one port disposed in fluid
communication with the incoming fluid flow accelerator bore and
oriented to direct a portion of the incoming fluid flowing through
the incoming fluid flow accelerator bore toward the opened upper
end of the shroud.
3. The downhole tool of claim 1, wherein the upper end of the
shroud comprises a plurality of openings.
4. The downhole tool of claim 1, wherein screen outer wall surface
is concentric with an inner wall surface of the shroud.
5. The downhole tool of claim 1, wherein the screen outer wall
surface defines a screen outer diameter and a shroud inner wall
surface defines a shroud inner diameter, the shroud inner diameter
being greater than the screen outer diameter to partially define
the cavity.
6. The downhole tool of claim 1, wherein the incoming fluid flow
accelerator bore comprises a shape to increase a velocity of an
incoming fluid flowing through the incoming fluid flow accelerator
bore.
7. A downhole tool for capturing debris within a wellbore, the
downhole tool comprising: a screen member having a screen upper
end, a screen lower end, a screen outer wall surface, a screen
inner wall surface defining a screen bore, and at least one screen
aperture in fluid communication with the screen inner wall surface
and the screen outer wall surface; a nozzle assembly disposed above
the screen member, the nozzle assembly comprising a nozzle bore
shaped to increase a velocity of an incoming fluid flowing through
the nozzle bore toward the screen bore, the nozzle bore being in
fluid communication with the screen bore; and a shroud disposed
around a portion of the screen member, the shroud comprising a
shroud upper end, a shroud lower end, a shroud outer wall surface,
and a shroud inner wall surface, the shroud upper end having an
opening, the shroud lower end being closed, and the shroud inner
wall surface, the shroud lower end, and the screen outer wall
surface define a cavity within the shroud.
8. The downhole tool of claim 7, wherein the nozzle bore comprises
a variable inner diameter that decreases from an upper end of the
nozzle assembly toward a lower end of the nozzle assembly.
9. The downhole tool of claim 7, wherein the screen member
comprises a screen upper end inner diameter that is smaller than a
screen lower end inner diameter.
10. The downhole tool of claim 7, wherein shroud upper end includes
a plurality of openings.
11. The downhole tool of claim 7, wherein the nozzle assembly
further comprises at least one secondary nozzle jet in fluid
communication with the nozzle bore and oriented to direct the
incoming fluid flowing through the nozzle bore toward the opening
disposed in the shroud upper end.
12. The downhole tool of claim 11, wherein at least one of the at
least one secondary nozzle jets is directly aligned with at least
one of the one or more openings disposed in the shroud upper
end.
13. The downhole tool of claim 7, wherein a lower end of the nozzle
assembly is connected to the screen member upper end.
14. A work string for capturing debris within a wellbore, the
downhole tool comprising: a first downhole tool, the first downhole
tool comprising a first screen member having a first screen upper
end, a first screen lower end, a first screen outer wall surface, a
first screen inner wall surface defining a first screen bore, and
at least one first screen aperture in fluid communication with the
first screen inner wall surface and the first screen outer wall
surface; a first incoming fluid flow accelerator disposed above the
first screen member, the first incoming fluid flow accelerator
comprising a first incoming fluid flow accelerator bore, the first
incoming fluid flow accelerator bore being in fluid communication
with the first screen bore; and a first shroud disposed around a
portion of the first screen member, the first shroud having a first
opening disposed toward an upper end of the first shroud and a
first closed end to define a first cavity.
15. The work string of claim 14, further comprising: a second
downhole tool, the second downhole tool comprising a second screen
member having a second screen upper end, a second screen lower end,
a second screen outer wall surface, a second screen inner wall
surface defining a second screen bore, and at least one second
screen aperture in fluid communication with the second screen inner
wall surface and the second screen outer wall surface; a second
incoming fluid flow accelerator disposed above the second screen
member, the second incoming fluid flow accelerator comprising a
second incoming fluid flow accelerator bore, the second incoming
fluid flow accelerator bore being in fluid communication with the
second screen bore; and a second shroud disposed around a portion
of the second screen member, the second shroud having a second
opening disposed toward an upper end of the second shroud and a
second closed end to define a second cavity, wherein the second
incoming fluid flow accelerator bore is in fluid communication with
the first screen bore.
16. The work string of claim 15, wherein the first downhole tool is
disposed adjacent the second downhole tool.
17. A method of removing debris from a wellbore fluid, the method
comprising the steps of: (a) flowing an incoming fluid through a
screen bore of a screen member and out of a lower end of the screen
member into a wellbore environment; (b) after step (a), combining
the incoming fluid with a wellbore fluid disposed in the wellbore
environment to form a combination fluid, the wellbore fluid
comprising a piece of debris; (c) flowing the combination fluid
upward within a wellbore annulus; (d) creating a first pressure
differential between the screen bore and the wellbore annulus
outside the screen member, the first pressure differential causing
the combination fluid to be drawn toward the screen member; (e)
passing the combination fluid through the screen member causing the
piece of debris within the combination fluid to be prevented from
passing through the screen, thereby causing the piece of debris to
be captured within a cavity formed by a shroud disposed around an
outer wall surface of the screen member.
18. The method of claim 17, wherein the first pressure differential
is created by the incoming fluid flowing through a bore of a fluid
flow accelerator before entering the screen bore of the screen
member, the fluid flow accelerator increasing a first velocity of
flow of the incoming fluid to a second velocity of flow.
19. The method of claim 18, wherein a second pressure differential
is created within the wellbore annulus between the upper end of the
shroud and an outer wall surface of the shroud, the second pressure
differential causing the combination fluid to be drawn toward the
screen member.
20. The method of claim 17, wherein prior to step (d) the
combination fluid flows upward within the wellbore annulus and
enters an opening at an upper end of the shroud and a portion of
the incoming fluid exits the bore of the incoming fluid flow
accelerator toward the opening at the upper end of the shroud
before entering the screen bore.
Description
BACKGROUND
[0001] 1. Field of Invention
[0002] The invention is directed to a downhole clean-up tool or
junk basket for use in oil and gas wells, and in particular, to a
downhole clean-up tool that is capable of creating a pressure
differential to transport debris from within the wellbore annulus
through a screen where it can be collected by the tool.
[0003] 2. Description of Art
[0004] Downhole tools for clean-up of debris in a wellbore are
generally known and are referred to as "junk baskets." In general,
the junk baskets have a screen or other structure that catches
debris as debris-laden fluid flows through the screen of the tool.
Generally, this occurs because at a point in the flow path, the
speed of the fluid carrying the debris decreases such that the junk
or debris falls out of the flow path and into a basket or
screen.
SUMMARY OF INVENTION
[0005] Broadly, downhole tools for clean-up of debris within a well
comprise a screen member having a cavity disposed around the outer
wall surface of the screen member. A fluid pumped downward through
the tool travels through the bore of the screen member and out of
the bottom of the tool. In so doing, a low pressure zone is created
within the bore of screen member causing wellbore fluid to flow
from the wellbore annulus and through the screen where it is
circulated back down through the bore of the screen member and out
the bottom of the tool. In so doing, debris carried in the wellbore
fluid is trapped by the screen and collected in the cavity.
Further, when the lower end of the tool is placed near the bottom
of the wellbore, or near a collection of debris within the
wellbore, the fluid exiting the bottom of the tool stirs up the
debris so that it can be carried upward and into the cavity.
[0006] In certain embodiments, a single tool is disposed in a work
string. In other embodiments, two or more tools are disposed in a
work string, either adjacent each other or spaced apart, so that
additional debris can be collected during a single trip into the
wellbore.
BRIEF DESCRIPTION OF DRAWINGS
[0007] FIG. 1 is a partial cross-sectional view of a specific
embodiment of a downhole tool disclosed herein shown disposed in a
wellbore.
[0008] FIG. 2 is partial cross-sectional view of the downhole tool
shown in FIG. 1 taken along line 2-2.
[0009] FIG. 3 is a partial cross-sectional view of two of the
downhole tools shown in FIG. 1 shown disposed adjacent each other
as part of a work string.
[0010] FIG. 4 is a partial cross-sectional view of another specific
embodiment of a downhole tool disclosed herein shown disposed in a
wellbore.
[0011] FIG. 5 is a cross-sectional view of an additional specific
embodiment of a downhole tool disclosed herein.
[0012] While the invention will be described in connection with the
preferred embodiments, it will be understood that it is not
intended to limit the invention to that embodiment. On the
contrary, it is intended to cover all alternatives, modifications,
and equivalents, as may be included within the spirit and scope of
the invention as defined by the appended claims.
DETAILED DESCRIPTION OF INVENTION
[0013] Referring now to FIGS. 1-2, in one particular embodiment,
downhole tool 20 is disposed within a wellbore or well 10 having
casing 12 by running tool 20 into wellbore 10 on work or tool
string 14 having tool string bore 16. In the embodiment of FIG. 1,
downhole tool 20 comprises incoming fluid flow accelerator 30,
screen member 40, and shroud 60.
[0014] Incoming fluid flow accelerator 30 facilitates increasing
the velocity of an incoming fluid (not shown) flowing down tool
string bore 16 in the direction of arrow 11 before entering screen
member 40. As illustrated in FIG. 1, incoming fluid flow
accelerator 30 comprises upper end 31, lower end 32, outer wall
surface 33, and inner wall surface 34 defining bore 35. In the
embodiment shown in FIG. 1, the shape and size of bore 35 causes
the increase in velocity of the incoming fluid as it flows through
bore 35 in the direction of arrow 11. In the particular embodiment
of FIG. 1, incoming fluid flow accelerator bore 35 is a "step-down"
bore meaning that the inner diameter of bore 35 progressively
decreases at stepped intervals from upper end 31 toward lower end
32. Although bore 35 is shown as being a "step-down" bore, it is to
be understood that bore 35 could have other shapes and sizes to
facilitate increasing the velocity of the incoming fluid as it
flows through bore 35 from upper end 31 toward lower end 32. For
example, bore 35 could comprise an inverted-conical shape that
decreases in inner diameter from upper end 31 toward lower end
32.
[0015] In the specific embodiment of FIGS. 1-2, screen member 40 is
connected to incoming fluid flow accelerator 30. Although screen
member 40 is shown in the embodiment of FIG. 1 as being connected
directly to incoming fluid flow accelerator 30, it is to be
understood that screen member 40 is not required to be connected
directly to incoming fluid flow accelerator 30. To the contrary,
one or more intermediate components may be disposed between
incoming fluid flow accelerator 30 and screen member 40.
[0016] Screen member 40 comprises upper end 41, lower end 42, outer
wall surface 43, inner wall surface 44 defining screen bore 45,
upper inner diameter 46, and lower inner diameter 47. In the
embodiment of FIGS. 1-2, upper inner diameter 46 is smaller than
lower inner diameter 47. Apertures 48 place outer wall surface 43
in fluid communication with inner wall surface 44 and, thus screen
bore 45, are disposed along a portion of inner and outer wall
surfaces 43, 44. As shown in FIG. 1, no apertures 48 are disposed
above the top of shroud 60; however, the location of apertures 48
is not required to be so limited. Instead, additional apertures can
be disposed above the top of shroud 60. Apertures 48 can having any
shape and size desired to allow fluid to flow through, yet small
enough to prevent certain sized debris from flowing through. For
example, apertures 48 can be circular or other shaped holes, slots,
or comprise a wrapped screen that provides randomly shaped
openings.
[0017] Shroud 60 comprises upper end 61, lower end 62, outer wall
surface 63, and inner wall surface 64 defining shroud bore 65.
Upper end 61 includes one or more openings 66. Upper end 61 may be
completely opened, i.e., having a single opening 66 not having any
portion of upper end 61 being attached to outer wall surface 43 of
screen member 40. Alternatively, one or more portions of upper end
61 may be connected to outer wall surface 43 of screen member 40 to
provide an increase in tensile and torque strength of tool 20. In
such embodiments, one or more openings 66 may be disposed within
upper end 61. For example, as illustrated in FIG. 2, upper end 61
includes a plurality of openings 66.
[0018] Outer and inner wall surfaces 63, 64 of shroud 60 do not
include holes or apertures and lower end 62 is secured to outer
wall surface 43 of screen member 40. Accordingly, cavity 68 is
defined by outer wall surface 43 of screen and inner wall surface
63 of shroud 60. In the embodiment of FIGS. 1-2, shroud 60 is
concentric with screen member 40. In addition, as shown in FIGS.
1-2, shroud 60 comprises a larger outer diameter compared to the
outer diameter of screen member 40.
[0019] In operation, downhole tool 20 is placed in tool string 14
and lowered to the desired location within wellbore 10. An incoming
fluid is then transported down bore 16 of tool string 14 and, thus,
into bore 35 of incoming fluid flow accelerator 30. The velocity of
the incoming fluid is increased as it exits lower end 32 of
incoming fluid flow accelerator 30 in the direction of arrow 11 and
enters screen bore 45 of screen member 40. Due to the velocity of
the incoming fluid flowing through screen bore 45, a pressure
differential is created across one or more of apertures 48 between
the screen bore and wellbore annulus portion 19. As a result, fluid
within wellbore annulus portion 19 is drawn toward screen member
45, and thus, into cavity 68 and through apertures 48.
[0020] The incoming fluid continues to flow downward through screen
bore 45 until it exits lower end 42 of screen member 40 as
indicated by arrow 13. Due to the increase in size of lower inner
diameter 47, the incoming fluid velocity decreases before exiting
lower end 42.
[0021] Upon exiting lower end 42, the incoming fluid mixes with
wellbore fluid contained within wellbore 10. The wellbore fluid
includes one or more pieces of debris. The mixture of the incoming
fluid and the wellbore fluid is referred to herein as the
"combination fluid." The combination fluid is carried upward within
wellbore 10 in the direction of arrows 15. As a result, debris that
is desired to be captured by tool 20 is carried upward. Upon
reaching upper end 61 of shroud 60, the pressure differential
between screen bore 45 and wellbore annulus portion 19 causes the
combination fluid to be drawn toward screen bore 45 and, thus, into
cavity 68 as indicated by arrows 17 and through apertures 48. In so
doing, debris within the combination fluid is prevented from
flowing through apertures 48 and is captured within cavity 68. The
portion of combination fluid that can pass through apertures 48
mixes with the incoming fluid flowing into screen bore 45 from
incoming fluid flow accelerator bore 35.
[0022] It is to be understood that even though some of the
combination fluid mixes with the incoming fluid after the
combination fluid passes through apertures 48 of screen member 40,
and some of this combination fluid may still contain small debris
within it, for simplicity, the resulting mixture of the fluid that
has passed through apertures 48 of screen member 40 and fluid that
is flowing from tool string bore 16, through bore 35 of fluid flow
accelerator 30 continues to be referred to herein as the "incoming
fluid." Thus, the term "incoming fluid" means any fluid flowing
downward through bore 35 of fluid flow accelerator 30 or bore 45 of
screen member 40 and out of lower end 42 of screen member 40 and
"combination fluid" means the mixture of the fluid exiting lower
end 42 of screen member 40 with the wellbore fluid.
[0023] In the particular embodiment of FIGS. 1-2, outer wall
surface 63 of shroud 60 provides a restricted wellbore annulus
portion 18. At the top of shroud 60, however, portion 19 of the
wellbore annulus is not so limited, i.e., it is larger than portion
18. This arrangement creates a pressure differential that increases
the velocity of flow of the combination fluid upward through
wellbore annulus portion 18 to facilitate lifting of larger pieces
of debris; and decreases the upward velocity of the combination
fluid through wellbore annulus portion 19 to facilitate movement of
the combination fluid (and debris carried with it) toward screen
bore 45 and, thus, into cavity 68.
[0024] Circulation of the combination fluid upward can be
facilitated by placing tool 20 above a restriction or blockage
within wellbore 12. For example, tool 20 can be placed near a
bridge plug, packer, or other isolation device. Alternatively, tool
20 can be placed toward the bottom of wellbore 12.
[0025] Downhole tool 20 can remain within wellbore 12 until cavity
68 is filled with debris or until all debris within wellbore 12 is
captured within cavity 68. Thereafter, downhole tool 20 is removed
from wellbore 12 and, in so doing, the debris captured within
cavity 68 is also removed.
[0026] Referring now to FIG. 3, in another embodiment, two downhole
tools 20, each as described with respect to the downhole tools of
FIGS. 1-2, are connected to each other within tool string 14.
Although downhole tools 20 are shown as being identical to each
other, it is to be understood that both downhole tools 20 are not
required to be identical to each. To the contrary, one or both of
downhole tools 20 can be modified as desired or necessary in
accordance with this disclosure and placed within tool string
14.
[0027] Moreover, although shown as being connected directly to each
other within tool string 14, it is to be understood that the two
downhole tools 20 shown in FIG. 3 can disposed within tool string
14 with one or more additional components between them. It is also
to be understood that although only two downhole tools 20 are shown
in FIG. 3, three or more downhole tools, whether identical to each
other, or modified as desired or necessary in accordance with this
disclosure, can be disposed in tool string 14, either connected
directly to each other or disposed within tool string 14 with one
or more other component disposed between one or more of the
downhole tools 20.
[0028] Placing two downhole tools 20 within tool string 14 permits
additional debris to be captured from the wellbore fluid during
each downhole run of tool string 14. As shown in FIG. 3, incoming
fluid flows down bore 16 of tool string 14, through bore 35 of
incoming fluid flow accelerator 30 of the upper downhole tool 20 as
indicated by arrow 111. The incoming fluid then exits lower end 42
of screen member 40 of the upper downhole tool 20 and into bore 35
of incoming fluid flow accelerator 30 of the lower downhole tool 20
as indicated by arrow 113. The incoming fluid then exits lower end
42 of screen member 40 of the lower downhole tool 20 and enters
wellbore 12.
[0029] Upon entering wellbore 12, the incoming fluid mixes with the
wellbore fluid, which includes one or more pieces of debris and is
carried upward as indicated by arrows 115. As the now combined
mixture of incoming fluid and wellbore fluid containing debris (the
combination fluid) is transported upward within the wellbore
annulus, a first portion of the combination fluid is pulled toward
screen bore 45 of screen member 40 of the lower downhole tool 20 as
indicated by arrows 116. As a result, the debris within this first
portion of combination fluid is blocked from entering screen bore
45 of the lower downhole tool 20 and, thus, is captured within
cavity 68 of the shroud 60 of the lower downhole tool 20.
[0030] A second portion of the combination fluid continues to flow
upward within the wellbore annulus as indicated by arrows 117. This
second portion of combination fluid is pulled toward screen bore 45
of screen member 40 of the upper downhole tool 20 as indicated by
arrows 118. As a result, the debris within this second portion of
combination fluid is blocked from entering screen bore 45 of the
upper downhole tool 20 and, thus, is captured within cavity 68 of
the shroud 60 of the upper downhole tool 20. As with the
embodiments of FIGS. 1-2, the two downhole tools 20 can remain
within wellbore 12 until cavities 68 of both downhole tools 20 are
filled with debris or until all debris within wellbore 12 is
captured within cavities 68. Thereafter, downhole tool 20 is
removed from wellbore 12 and, in so doing, the debris captured
within cavity 68 is also removed.
[0031] Referring now to FIG. 4, downhole tool 120 comprises
incoming fluid flow accelerator 130, screen member 40, and shroud
60. Screen member 40 and shroud 60 are unchanged from the various
embodiments of screen member 40 and shroud 60 discussed above with
respect to the embodiments of FIGS. 1-2. Other than the differences
discussed with respect to FIG. 4, incoming fluid flow accelerator
130 has the same structures as incoming fluid flow accelerator 30
of FIGS. 1-2.
[0032] As shown in FIG. 4, incoming fluid flow accelerator 130
comprises bore 135 that is in fluid communication with screen bore
45 of screen member in the same manner as the embodiments of FIGS.
1-2, however, incoming fluid flow accelerator 130 further includes
one or more wellbore annulus ports 138 that place bore 135 in fluid
communication with wellbore annulus portion 19. Ports 138 permit
the incoming fluid to exit incoming fluid flow accelerator 130 in
the direction of arrows 139 to facilitate directing the combination
fluid into cavity 68 of shroud 60. In one specific embodiment,
ports 138 are oriented or directed toward opening(s) 66 of FIGS.
1-2. In other words, as shown in FIG. 4, ports 138 are aligned with
at least one opening 66. In other embodiments, ports 138 are not
aligned with any opening(s) 66, but instead are directed into the
wellbore annulus to create a hydraulic barrier that restricts
debris laden fluid from flowing upward. By restricting such flow,
ports 138 are facilitating the flow of the debris laden fluid into
opening(s) 66. In certain embodiment, ports 138 are nozzle
jets.
[0033] In operation of the specific embodiment of FIG. 4 having
ports 138 aligned with one or more opening 66, when the combination
fluid reaches the top of shroud 60, the incoming fluid exiting
ports 138 directs the combination fluid into cavity 68. Ports 138,
therefore, facilitate movement of the combination fluid toward
screen member 40. The movement of the combination fluid toward
screen member 40 by the incoming fluid exiting ports 138 may be
desirable or necessary where a suitable pressure differential is
too low or absent between screen bore 45 and wellbore annulus
portion 19 such as where apertures 48 are being blocked by debris
captured in cavity 68.
[0034] Referring now to FIG. 5, in another embodiment, downhole
tool 220 comprises incoming fluid flow accelerator 230, screen
member 240, shroud 260, and lower sub 270. Lower sub 270 includes
bore 275 in fluid communication with screen member bore 245. In the
embodiment of FIG. 5, incoming fluid flow accelerator 230 comprises
bore 235 having screen port 234 and one or more shroud ports 236.
Screen port 234 permits fluid to flow from incoming fluid flow
accelerator bore 235 into screen member bore 245. Shroud ports 236
permit fluid to flow from fluid flow accelerator bore 235 into
shroud cavity 268. Screen port 234 and shroud ports 236 can have
any shape or size desired or necessary to facilitate injection of
an incoming fluid from incoming fluid flow accelerator bore 235
into screen member bore 245 and shroud cavity 268, respectively,
such that debris can be captured within shroud cavity 268.
[0035] In addition to these ports, incoming fluid flow accelerator
230 of the embodiment of FIG. 5 also includes one or more wellbore
annulus ports 238 that allow fluid to flow from fluid flow
accelerator bore 235 into the wellbore annulus (not shown).
Wellbore annulus ports 238 can have any shape or size desired or
necessary to facilitate creation of a hydraulic barrier above
debris inlet ports 269 to facilitate movement of the combination
fluid from the wellbore annulus through debris inlet ports 269
toward screen member 240.
[0036] Although the embodiment of FIG. 5 is shown as having screen
port 234, shroud ports 236, and wellbore annulus ports 238, it is
to be understood that downhole tool 220 is not required to include
all of these ports. To the contrary, downhole tool 220 can include
only screen port 234, or only one or more shroud ports 236, or only
one or more wellbore annulus ports 238, or any combination of these
three types of ports.
[0037] In the embodiment of FIG. 5, shroud 260 is secured directly
to incoming fluid flow accelerator 230 by a fastener such as
threads. Disposed through the outer and inner wall surfaces 261,
262, respectively, of shroud 260 are debris inlet ports 269. Lower
sub 270 is secured to the lower end of shroud 260 by a fastener
such as threads. Although not required to do so, lower sub 270
closes off the lower end of shroud 260 to, along with the inner
wall surface of shroud 260 and the outer wall surface of screen
240, define shroud cavity 268.
[0038] Downhole tool 220, when placed in a work string, facilitates
debris disposed within the wellbore (not shown) to be picked up and
flowed upward within the wellbore annulus (not shown) until the
combination fluid containing debris flows through debris inlet
ports 269. In one particular embodiment, an incoming fluid is
flowed downward through the work string and into incoming fluid
flow accelerator bore 235. The incoming fluid then exits incoming
fluid flow accelerator 230 through screen member port 234 and flows
into screen member bore 245. The incoming fluid continues to flow
downward until it flows through lower sub bore 275 and into the
wellbore, such as through a mill disposed below lower sub 270. The
incoming fluid then mixes with the wellbore fluid, which contains
debris, to form the combination fluid which flows upward within the
wellbore annulus. The combination fluid then enters debris inlet
ports 269. The downward flow of the incoming fluid through screen
member bore 245 draws the combination fluid toward the screen where
the debris is prevented from passing through the screen so that it
falls into shroud cavity 268 in a similar manner as discussed above
with respect to the embodiments of FIGS. 1-2.
[0039] When present, the one or more shroud ports 236 facilitate
directing the combination fluid flowing through debris inlet ports
269 toward screen member 240 by, for example, pushing the
combination fluid toward apertures 248 after the combination fluid
has flowed through debris inlet ports 269.
[0040] When present, the one or more wellbore annulus ports 238
facilitate directing the combination fluid flowing through debris
inlet ports 269 toward screen member 240 by, for example, creating
a hydraulic barrier within the wellbore annulus to prevent the
combination fluid to flow upward past debris inlet ports 269.
[0041] It is to be understood that the invention is not limited to
the exact details of construction, operation, exact materials, or
embodiments shown and described, as modifications and equivalents
will be apparent to one skilled in the art. For example, the bore
of the incoming fluid flow accelerator can have any shape desired
or necessary to increase the velocity of the incoming fluid as it
passes through the incoming fluid flow accelerator bore.
Alternatively, the incoming fluid flow accelerator can use another
structure or device, instead of the shape or size of the incoming
fluid flow accelerator bore, to increase the velocity of the
incoming fluid as it flows through the incoming fluid flow
accelerator. Moreover, the incoming fluid flow accelerator is not
required to be attached directly to the screen member. Instead, one
or more additional components of the work string can be dispose
between the incoming fluid flow accelerator and the screen member.
Further, the lower portion of the screen bore is not required to
have a larger inner diameter compared to an inner diameter of an
upper portion of the screen bore. Instead, the upper portion inner
diameter can be larger than or equal to the lower portion inner
diameter as desired or necessary to facilitate movement of the
incoming fluid downward through screen bore and/or to facilitate
mixing the incoming fluid with the wellbore fluid and/or lifting
the combination fluid upward through the wellbore annulus.
Additionally, the apertures in the screen member are not required
to be absent above the top of the shroud as shown in FIGS. 1, 3,
and 4, but instead can extend above the top of the shroud. In
addition, the shroud is not required to be disposed concentrically
with the screen member. Instead, it can be disposed eccentrically
so that one side has a larger opening compared to another side to
facilitate capturing larger sized debris on that side. Nor are the
shroud or the screen member both required to have a circular
cross-section. Instead, one or both of the shroud or the screen
member can have a square or other cross-sectional shape as desired
or necessary to facilitate capturing debris within the cavity of
the shroud.
[0042] Further, it is to be understood that the term "wellbore" as
used herein includes open-hole, cased, or any other type of
wellbores. In addition, the use of the term "well" is to be
understood to have the same meaning as "wellbore." Moreover, in all
of the embodiments discussed herein, upward, toward the surface of
the well (not shown), is toward the top of Figures, and downward or
downhole (the direction going away from the surface of the well) is
toward the bottom of the Figures. However, it is to be understood
that the tools may have their positions rotated in either direction
any number of degrees. Accordingly, the tools can be used in any
number of orientations easily determinable and adaptable to persons
of ordinary skill in the art. Accordingly, the invention is
therefore to be limited only by the scope of the appended
claims.
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