Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Wellbore Tubular and Method
Field
The invention relates to wellbore structures and, in particular, nozzles and
tubulars for
wellbore fluid control.
Background
Various wellbore nozzles and tubulars are known and serve various purposes.
Tubulars are employed to both inject fluids into and conduct fluids from a
wellbore.
In some cases, nozzles are employed to control the flow and pressure
characteristics
of the fluid moving through the wellbore.
Wellbore tubulars with nozzles have failed in some challenging wellbore
conditions,
such as in steam or acid injection operations. Improved nozzled tubulars are
of
interest.
Summary
In accordance with another broad aspect, there is a wellbore tubular
comprising: a
base pipe including a wall; a port through the wall providing access between
an inner
diameter of the base pipe and an outer surface of the base pipe; a nozzle in
the port,
the nozzle including an orifice; and a diffuser tube on the outer surface to
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fluid exiting the orifice, the diffuser tube including an inlet port opening
to an inner
diameter within a tubular wall of the diffuser tube, a fluid diffusing wall at
a bend
within the diffuser tube and a plurality of outlet ports from the diffusing
tube.
In accordance with another broad aspect, there is a method for handling fluid
in a
wellbore comprising: forcing fluid flows through a nozzle orifice which
extends from
an inner diameter of a tubular to an outer surface of the tubular; and
directing the fluid
flowing from the nozzle orifice along the outer surface and into a diffuser
tube to
diffuse energy of the fluid flowing from the nozzle orifice before the fluid
exits the
tubular.
It is to be understood that other aspects of the present invention will become
readily
apparent to those skilled in the art from the following detailed description,
wherein
various embodiments of the invention are shown and described by way of
illustration.
As will be realized, the invention is capable for other and different
embodiments and
its several details are capable of modification in various other respects, all
without
departing from the spirit and scope of the present invention. Accordingly the
drawings and detailed description are to be regarded as illustrative in nature
and not as
restrictive.
Brief Description of the Drawings
Drawings are included for the purpose of illustrating certain aspects of the
invention.
Such drawings and the description thereof are intended to facilitate
understanding and
should not be considered limiting of the invention. Drawings are included, in
which:
Figure 1 is a perspective view of a wellbore tubular;
Figure 2 is a section along line I-I of Figure 1;
Figure 3 is a section through line II-II of Figure 2;
Figure 4 is an enlarged section through a nozzle installed in the wall of a
tubular;
Figure 5 is an exploded perspective view of the components of a nozzle to be
installed
in the wall of a tubular;
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Figure 6 is a perspective view of a nozzle seat;
Figure 7 is an enlarged sectional view of a nozzle;
Figure 8 is an enlarged section through a nozzle installed in the wall of a
tubular;
Figure 9 is an axial sectional view through a tubular with a diffuser therein;
Figure 10 is a section along of Figure 9;
Figure 11 is a section along IV-IV of Figure 10;
Figure 12 is sectional view of another tubular, the sectional view being
similar to that
of Figure 10, but passing through the nozzle;
Figure 13 is a perspective view of the diffuser and nozzle arrangement of the
tubular
of Figure 12 with the shield removed; and
Figure 14 is a section along V-V of Figure 13.
Detailed Description of Various Embodiments
The detailed description set forth below in connection with the appended
drawings is
intended as a description of various embodiments of the present invention and
is not
intended to represent the only embodiments contemplated by the inventor. The
detailed description includes specific details for the purpose of providing a
comprehensive understanding of the present invention. However, it will be
apparent
to those skilled in the art that the present invention may be practiced
without these
specific details.
Referring to Figures 1 to 3, a wellbore tubular 10 is shown, The wellbore
tubular is
for conveying fluid into or out of a well and for permitting fluid to pass
between its
inner diameter and its outer surface. The tubular has a durable construction
and may
even accommodate the significant rigors presented by handling steam flows. The
wellbore tubular may be formed using various constructions. For example, the
ends
10a of the wellbore tubular may be formed for connection to adjacent wellbore
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tubulars. As will be appreciated, while the tubular's ends are shown as
blanks, they
may be formed in various ways for connection end to end with other tubulars to
form
a string of interconnected tubulars, such as, for example, by formation at one
or both
ends as threaded pins, threaded boxes or other types of connections,
Wellbore tubular 10 includes a base pipe 12 with one or more ports 14 through
the
base pipe wall. Fluids may pass through ports 14 between the base pipe's inner
diameter ID defined by inner surface 12a and its outer surface 12b. Depending
on the
mode of operation intended for the wellbore tubular, fluid flow can be
inwardly
through the ports toward inner diameter ID or outwardly through the ports from
inner
diameter ID to the outer surface 12b.
The inner diameter generally extends from end to end of the tubular such that
the
tubular can act to convey fluids from end to end therethrough and be used to
form a
length of a longer fluid conduit through a plurality of connected tubulars.
The tubular may include a shield 16 mounted to base pipe 12. The shield may be
positioned to overlap the ports. Shield 16 may be spaced from outer surface
12b such
that an annular space 18 is provided between the shield and outer surface 12b.
There are openings from space 18 to the exterior of the tubular, which is the
outer
surface 12b exposed beyond the shield. For example, there may be openings 18a
through the shield or at the end edges 16a of shield 16 where fluid can flow
into or out
of space 18. In the illustrated embodiment of Figure 2, shield 16 is spaced at
at least
some edges 16a from outer surface 12b such that there are openings 18a through
which space 18 can be accessed at those edges. In some embodiments, as shown,
the
shield may be positioned to encircle base pipe 12 at the ports 14 and,
therefore, may
be shaped as a sleeve, as shown with space 18 formed as an annulus and with
annular
access openings 18a at both ends of the sleeve.
The openings may take other forms in other embodiments, depending on the form
of
the base tubular, sleeve, and mode of operation. For example, in one
embodiment, the
118a openings may be formed in whole or in part by grooves 119 in the outer
surface
112b of the base pipe (Figure 8).
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Shield 16 may serve a number of purposes including, for example, protecting
the
ports from abrasion and diverting flow for fluid velocity control. For
example, shield
16 diverts flow between the exterior of the tubular and ports 14, such that it
must pass
along outer surface 12b of base pipe. Flow, therefore, cannot pass directly
radially
between the exterior of the tubular and inner diameter ID. In particular,
because shield
16 overlaps the ports, ports 14 open into space 18, flow between exterior of
the
tubular and the inner diameter changes direction at least once: at the
intersection of
port 14 and space 18. While flow through the ports 14 is radial relative to
the long
axis xb of the tubular, flow between the ports and the exterior of the tool is
through
space 18 and that flow is substantially orthogonal relative to the radial flow
through
ports 14.
Each port 14 has a nozzle assembly 20 installed therein. The nozzle assembly
permits
flow control through the port in which it is installed, With reference also to
Figure 4,
nozzle assembly 20 includes at least a nozzle 22 and may include an
installation
fitting 24.
Nozzle 22 includes an orifice 26 extending through the nozzle body through
which
fluid passes through the nozzle and therefore through the port. In particular,
a nozzle
22 is installed in each port such that flow through the port is controlled by
the shape
and the configuration of orifice 26.
Nozzle 22 is formed of a material that can withstand the erosive rigors
experienced
down hole such as via abrasive flows, high velocity flows, corrosive flows
with acid
and/or steam passing through orifice 26. Nozzle 22 may, for example, be formed
of a
material different, for example, harder than the material forming base pipe
12. The
base pipe is, for example, usually formed of steel such as carbon steel and
nozzle 22
may be formed of a material harder than the carbon steel of base pipe 12. In
some
embodiments, for example, nozzle 22 may be formed of tungsten carbide,
stainless,
hardened steel, filled materials, etc.
Orifice 26 may be shaped to allow non-linear flow through nozzle 22. In
particular,
orifice 26 defines a path through the nozzle, through which fluid flows, and
the path
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from its inlet end to its outlet end is non-linear, including at least one
bend or elbow
that causes at least one change in direction of the fluid flowing through the
orifice.
This bend may affect fluid flows in a number of ways to redirect the flow to a
more
favorable direction, to cause impingement of the fluid against a nozzle
surface or
another flow to diffuse energy from the flow, to mitigate erosive damage to
certain
surfaces and/or to create an extra back pressure to slow or otherwise control
flows of
certain fluids autonomously through the nozzle. For example, the geometry of
the
nozzle orifice 26 can be selected to choke selectively gas, water, steam or
oil.
For example with reference also to Figure 7, orifice 26 may include a
diverting bend
at y that diverts flow through the nozzle from a first direction to a second
direction
which is offset, out of line from the first direction, With reference to the
direction of
flow depicted through the nozzle of Figure 7, the first direction is shown by
arrow Fa
and the second direction is shown by arrow Fb. In one embodiment, the second
direction is substantially orthogonal to the first direction.
Nozzle 22 is positioned in a port and will have one end open to the inner
diameter ID
of the tubular and the other end open to the outer surface 12b. Generally, the
nozzle
is installed so that a base end 22a is installed adjacent and open to inner
surface 12a
and an opposite end 22b is installed adjacent and open to outer surface 12b.
Orifice
26 may be formed, therefore, to avoid straight through flow between base end
22a and
opposite end 22b. Orifice 26, for example, may include a portion defining a
main
aperture 26a and a portion defining a lateral aperture 26b. Main aperture 26a
extends
from an opening 26a' at a base end 22a of nozzle 22 to an end wall 26a" at an
opposite
end 22b of the nozzle. Lateral aperture 26b extends from the main aperture and
connects main aperture 26a to another opening 26b' adjacent opposite end 22b.
Lateral aperture 26b extends at an angle from the long axis of main aperture
26a. The
angular intersection of the axis of lateral aperture relative to the main
aperture may be
substantially orthogonal (+/- 45 ) and in one embodiment, for example, the
apertures
26a, 26b intersect at y at substantially 90 .
The nozzle may be substantially cylindrical with ends 22a, 22b and
substantially
cylindrical side walls extending between the ends. In such an embodiment, the
main
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aperture portion opens at an end and the pair of lateral aperture portions
opens on the
cylindrical side walls.
End wall 26a", which can be flat (planar) or domed (concave), prevents
straight
through flow through the nozzle and acts to divert flow from the first
direction in the
main aperture to the lateral direction through lateral aperture 26b.
Impingement of
fluid flows against wall 26a" dissipates energy from the flow and concentrates
erosive
energy against wall 26a" rather than surfaces beyond the nozzle. Orifice 26 is
formed
through the material of the nozzle and, thus, walls 26a" and the other walls
defining
orifice 26 are of erosion-resistant material. Thus, the diverting bend and in
particular
end wall 26a", can reliably accommodate the passage therethrough of erosive
flows
including that of steam. This foregoing description focuses on flow in only
one
direction through apertures 26a, 26b, but it is to be understood that flow can
be from
opening 26b' to opening 26a' (i.e. with the flow moving in the opposite
directions of
arrows Fa and Fb), if desired. See for example, Figure 8 wherein flow arrows F
through nozzle 122 pass in the opposite direction: from outer lateral aperture
portions
126b to main aperture portion 126a of orifice 126.
Orifice 26 may be further configured to control the flow characteristics of
fluid
passing therethrough. In one embodiment, apertures 26a, 26b may be sized to
limit
the volume of fluid capable of passing therethrough. For example, apertures
26h may
be smaller diameter openings, sized to allow less flow, than aperture 26a. For
example, the total cross sectional area of apertures 26b may be less than the
total cross
sectional area of aperture 26a, such that a back pressure is created when flow
is in the
direction of arrows Fa, Fb. Stated another way, the pressure drop is mainly
across
26b. The primary flow control through the nozzle is at lateral aperture 26b,
more so
than 26a.
Alternately or in addition, apertures 26a, 26b may be shaped to impart desired
flow
rate and/or pressure on the fluid passing therethrough. For example, lateral
aperture
26b, as shown, has internal shape with a jetting constriction to impart a jet
effect,
which generally includes a fluid acceleration and pressure change (i.e. drop),
in the
fluid passing therethrough. The shape of apertures 26a may change depending on
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whether the flow is intended to be with arrows Fb or against them or a
bidirectional
jetting shape may be employed with a symmetrical constriction similar to an
hour
glass.
In addition or alternately, there may be more than one main and/or lateral
aperture.
For example, as shown, orifice 26 may take the form of a T-shaped conduit with
at
least two lateral apertures 26b extending from the main aperture. However,
while two
lateral apertures 26b are shown, there may be only one or more than two such
apertures. Generally, there will be an even number of lateral apertures with
pairs
substantially diametrically opposed across the circumference of the main
aperture
26a. The diametric positioning, with one lateral aperture 26b opening into
main
aperture 26a at a position substantially opposite another lateral aperture 26b
(as shown
in Figure 7), allows fluid impingement when flow is inwardly from apertures
26b to
aperture 26a. This impingement may create a desired back pressure on the flow
through nozzle.
Nozzle 22 conveys fluid between openings 26a' and 26b' across the wall of the
base
pipe. One opening is exposed in the inner diameter of the base pipe and the
other
opening is exposed on outer surface 12b. If shield 16 is employed, fluid when
exiting
from nozzle 22, enters annulus 18. The position of orifice 26b' of lateral
aperture 26b
causes some fluid movement parallel to outer surface 12b, rather than straight
radially
out from port 14.
Nozzle 22 may be installed in any of various ways in its port 14. If desired,
nozzle
assembly 20 may include installation fitting 24 to hold nozzle 22 in its port
14. For
example, if the material of nozzle 22 prevents reliable engagement to base
pipe or is
formed of a material different than the material of the base pipe, a fitting
24 may be
employed to ensure a good fit of the nozzle in its port and may, for example,
reduce
the risk of nozzle 22 falling out of the port.
Installation fitting 24 may be formed to fit between the nozzle and the port.
For
example, the installation fitting may include a portion for being engaged in
the port
and a portion for securing nozzle. The portion for being engaged in the port
may vary
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depending on the form and the shape of the port and the desired mode of
installation
in port 14. In the illustrated embodiment, for example, installation fitting
24 includes
a threaded portion 28 as that portion engageable in the port. The port may
also
include threads 30 into which fitting 24 may be threaded.
The portion for securing the nozzle may also vary, for example, depending on
the
form and shape of nozzle 22 and the desired mode of installation of nozzle 22.
For
example, in one embodiment, nozzle 22 can be held rigidly by the fitting and
in
another embodiment, nozzle 22 may be installed to have some degree of movement
relative to the fitting, while being held against becoming entirely free of
the fitting.
Thus, as an example, fitting 24 in the illustrated example includes a passage
32 into
which nozzle 22 fits. Passage 32 passes fully through the fitting such that it
is open at
both ends of the fitting and, in other words, the fitting is formed as a ring.
When
nozzle 22 is installed in passage 32, opening 26a is exposed at one end of the
passage
and opening 26b' is exposed at the other end of the passage.
In this embodiment, nozzle 22 is secured rigidly into passage 32. For example,
nozzle
22 may be press fit and possibly mechanically shrunk fit, into passage 32. In
one
embodiment, fitting 24 may be heated to cause thermal expansion thereof that
enlarges the diameter across passage 32, nozzle 22 may be fit therein and
fitting 24
cooled to contract about the nozzle and, thereby, firmly engage it. In such an
embodiment, fitting 24 may include features to modify the hoop stresses about
the
ring to best accommodate heating expansion for press fitting. For example,
passage
32 and nozzle 22 may have a tapering diameter from end to end to facilitate
press
fitting these parts together. For example, nozzle 22 may have a tapering outer
diameter from one end to the other and passage 32 may have a tapering inner
diameter
from one end to the other end. The nozzle 22 may then be inserted and forced
into
passage 32 with the narrow end of the nozzle wedged into the narrow end of the
passage and the tapering sides of the parts in close contact. In addition or
alternately,
for modification of hoop strength, passage 32 may include notches 34 in the
otherwise
substantially circular sectional shape (orthogonal to the center axis x of
passage 32).
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In some embodiments, the material of nozzle 22 may have thermal expansion
properties different than the material of base pipe 12. As such, if nozzle 22
was
installed directly into base pipe 12, it may tend to become dislodged or
damaged in
use such as when in a high temperature (i.e. steam) environment. Generally,
the
materials most useful for the nozzle may have a low coefficient of thermal
expansion,
while the materials most useful for the base pipe 12 may have a reasonably
high
coefficient of thermal expansion and most often a nozzle firmly installed in a
port at
ambient temperatures may tend to fall out of a base pipe at elevated
temperatures. To
address issues caused by thermal expansion, installation fitting 24 may be
formed of a
material having a coefficient of thermal expansion selected to work well with
both the
nozzle and the base pipe. In one embodiment, installation fitting 24 is formed
of a
material having a coefficient of thermal expansion between those of the
materials of
the base pipe and the nozzle. In another embodiment, the coefficient of
thermal
expansion of fitting 24 is greater than that of base pipe 12. As such, when
undergoing
thermal stress, fitting 24 will undergo thermal expansion ahead of base pipe
12 and
fitting 24 stays firmly engaged in port. In such an embodiment, nozzle 22 and
fitting
24 can be connected when the fitting is thermally expanded.
Shield 16, if employed, may overlap the nozzle assembly to hold nozzle 22 in
the port
14. In one embodiment, nozzle 22 is fit in the port such that any movement to
fall out
of port is radially out towards outer surface 12b. A controlled installation
that tends
to allow nozzle 22 to only move outwardly towards the outer surface may be
achieved, for example, by tapering of the nozzle and the port/passage in which
it is
installed to have their wider ends radially outwardly positioned, for example
closer to
the outer surface of the base pipe. Shield 16 includes a plug 36 in a hole 38
that
substantially radially aligns with port 14. Plug 36 is removable to allow
opening of
hole 38 and access to port 14 and, thereby, installation of nozzle assembly 20
to port
14 through hole 38. After nozzle 22 is installed, plug 36 may be reinstalled
in hole 38
to overlie the nozzle. Plug 36 and hole 38, for example, may be threaded to
facilitate
removal and reinstallation of the plug.
Plug 36 can ensure that nozzle 22 remains in position in port 14 even if
nozzle 22
comes loose. For example, plug 36 can be formed to penetrate into hole 38
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sufficiently to bear down on end 22b of the nozzle. If there are tolerances
that may
prevent reliable fitting of the plug against end 22b of the nozzle, a flexible
spacer may
be employed. For example, as shown, there may be a spring 40 between plug 36
and
nozzle 22.
Nozzle assembly 20, in this embodiment including nozzle 22 and fitting 24 in
port 14,
allows fluid to move between inner diameter ID and outer surface 12b through
orifice
26. The lateral orifice 26b directs fluid flows that are adjacent opening 26b'
to pass
substantially parallel to outer surface 12b through annulus 18. To facilitate
flows
through the annulus with minimal erosive damage to shield 16, aperture 26b may
be
positioned such that flows therethrough pass somewhat parallel to the long
axis xb of
base pipe. For example, the nozzle 22 can be installed such that the axis xa
of
aperture 26b is within 60 and perhaps within 45 of long axis xb. In the
illustrated
embodiment, axis xa of aperture 26b is substantially aligned with long axis
xb.
To install a nozzle assembly in such an embodiment, plug 36 can be removed
from
hole 38, the nozzle assembly including at least nozzle 22 but possibly also
fitting 24
can be inserted through hole 38 and installed in port 14 with openings 26a'
and 26b'
exposed in inner diameter ID and annulus 18, respectively, and with axis xa of
aperture 26b directed in a selected direction, for example toward the open
edges 16a
of shield 16. Then plug 36 can be installed in hole 38 over nozzle 22. If
there is a
spacer, such as spring 40, it is positioned between nozzle 22 and plug 36. In
an
embodiment where the nozzle assembly includes fitting 24 and nozzle 22, these
parts
can be installed separately or may be connected ahead of installation.
Tubulars according to the present invention can take other forms as well. In
one
embodiment, as shown in Figure 8, tubular 110 includes a screening apparatus
150.
Tubular 110 is primarily useful for handling inflows, since screening
apparatus 150
removes oversize particles from the flows to opening 118a, Grooves 119 in
outer
surface 112b extend under apparatus 150, through openings 118a under an edge
of the
shield and into space 118 between outer surface 112b and shield 116. Space 118
opens to nozzle. It is noted that tubular 110 illustrates a nozzle 122 without
an
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additional installation fitting and, instead, nozzle 122 is secured directly
into the
material of base pipe.
During use of the tubular, fluid may pass through nozzle orifice 26 between
inner
diameter ID and outer surface 12b. Nozzle 22 diverts flow such that it passes
in a
non-linear fashion between inner diameter ID and outer surface 12b. Orifice 26
causes fluid flows to change direction as they pass through the nozzle
including both:
(i) substantially radially relative to the long axis xb of the base pipe and
(ii)
substantially parallel to the outer surface, which is possibly somewhat
parallel to the
long axis of the base pipe. This may direct flows through space 18 between
outer
surface 12b and shield 16 spaced from the outer surface. The fluid may flow
through
space 18, along outer surface 12b through an opening 18a, 118a to the annulus
about
the tubular.
Flows outwardly tend not to cause formation damage, as the fluid jetting
through the
nozzle is diverted from a radially outward direction (through aperture 26a) to
a lateral
direction through aperture 26b and along the outer surface of the base pipe,
which is
parallel to the wellbore wall. As such, the force of the fluid passing from
the tubular
is dissipated at end wall 26a" of the orifice, where the flow path diverts
laterally.
In use, nozzle 22 may control fluid flows by accommodating and avoiding
erosion
through ports and controlling velocity and pressure characteristics of the
flow.
For example, a method for accepting inflow of steam or produced fluids in a
paired,
heavy oil (such as oil sand), gravity drainage well may employ a tubular such
as is
depicted in Figures 1 to 3 or Figure 7. In paired well steam production, it is
desirable
that introduced steam create a steam chamber in the formation that heats the
heavy oil
and mobilizes it as produced fluids. The produced fluids are intended to flow
into a
producing well. Sometimes steam from an adjacent well may break through and
seek
to enter the producing well. Using a tubular, as described, steam may be
restricted
from passing into the tubular due to the form of the nozzle and the
configuration of
the nozzle in the tubular. In particular, the limited entry size of the
apertures first
limits the volume of produced fluids that can pass into the tubular. Also, the
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impingement of flows from the diametrically opposed apertures 26b tends to
resist
flows through the orifice 26 and creates a back pressure that limits flows
through the
nozzle. Also, the diverted flow path from aperture 26b to aperture 26a
dissipates fluid
force so that the tubular tends not to problematically erode. As such, a steam
chamber
may form outwardly of the tubular, even if a break through occurs from the
steam
injection well to the producing well.
During use, while forces may tend to act to dislodge nozzle from its position,
the
method may include holding the nozzle in place against the forces tending to
move
the nozzle into an inactive position. For example, the method may include
holding
the nozzle down into the port, for example, by a shield thereover.
Alternately, or in
addition, the method may include holding the nozzle against dislodgement by
differences in thermal expansion, for example, by use of a fitting. A fitting
may act
between the nozzle and the base pipe to hold the nozzle in place. For example,
the
fitting may prevent the nozzle from passing into the inner diameter due to a
taper in
the parts and the nozzle may have a thermal expansion that holds the nozzle in
place.
While the embodiment is described wherein nozzle 22 is rigidly installed in
fitting 24,
the nozzle in some embodiments can be slidably mounted in the fitting. For
example,
nozzle can slide into and out of the fitting depending on the pressures
against
openings 26a' and 26b'. As such, nozzle 22 can operate as a form of valve.
A nozzle, as described hereinbefore, may have an orifice shaped to restrict
flow in one
direction, but such an orifice may not restrict flow as much in the opposite
direction.
For example, with reference to Figures 9 to 13, a nozzle 222 may be installed
in a
tubular 212 intended to handle produced fluid flow, which is flow inwardly
from the
base pipe's outer surface 212b through the orifice of the nozzle.
Specifically, with
reference back to Figure 8, inward, produced fluid flow may be through a
lateral
aperture 126b of the orifice and then into a main aperture 126a of the
orifice, before
entering the inner diameter ID of the tubular, In such an embodiment, each
orifice
lateral aperture 126b has a smaller diameter inner end (the end closer to main
aperture
126a) and a larger diameter outer end (the end closer to space 118) and a
flaring
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diameter from the inner end to the outer end. This orifice shape creates back
pressure
on the fluid passing therethrough in the direction of arrows F.
With such a tubular, flow in the opposite direction, outwardly from the inner
diameter, ID through nozzle 122 to outer surface 112b may not be slowed by the
orifice and may, in fact, be accelerated such that the fluid passing from
nozzle 122,
out through lateral aperture 126b along outer surface 112b may have a high
velocity
and may be damaging to structures in the fluid path, especially if the fluid
is steam or
acid.
For example if it is desired to use tubular 110, that is intended to control
and slow
inflow of produced fluids into the tubular inner diameter, instead to pump
fluids
through from the tubular into the formation (in a direction opposite arrows
F), the
fluids passing from nozzle 122 may damage structures including parts of the
tubular
such as shield 116, base pipe outer surface 112b, screening materials 150, or
the
formation. Fluids, such as water, gas, steam or acid, passing from the nozzle
orifice
126b may cause erosion-corrosion.
A tubular 210 that provides both controlled, low stress inflow and controlled,
low
stress outflow through a nozzle 222 may include an outflow diffuser 260
positioned to
accept flow from the nozzle. The outflow diffuser 260 accepts flow and
dissipates
some of the energy therefrom before releasing the flow to exit and flow away
from
the tubular. The diffuser includes a wall positioned out of alignment, for
example
substantially orthogonally, to the axis xa (see Figure 7) of the orifice's
lateral apertures
226b.
The diffuser may be installed on outer surface 212b of the tubular wall to
receive
impingement from an outward flow from nozzle 222, which will be through the
orifice's lateral apertures 226b. There may be a diffuser for each lateral
aperture of
the nozzle. The diffuser is positioned adjacent the nozzle and generally in a
space
such as an exterior fluid chamber 218 such as one defined between a shield 216
and
outer surface 212b. The exterior fluid chamber has an opening 218a to the
exterior of
the tool through which fluid enters or exits the chamber. When fluid is
passing
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outwardly through nozzle 222, it follows an exit path from nozzle to opening
218a
where the fluid passes out from under the shield 216 to the exterior of the
shield.
Opening is part of the exit path for the fluid. The opening 218a may open
directly to
the exterior of the tool. Alternately, a filtering material 250 may be
disposed across
opening 218a to filter fluid passing through opening 218a.
In one embodiment, the diffuser is a tube positioned and configured to accept
fluids
exiting the nozzle at lateral apertures 226b and redirect and slow the fluids
before
releasing them to continue along the exit path and flow from the tubular. The
diffuser
tube has a tubular construction with a tubular wall defining there within an
inner
diameter that provides a conduit for fluids to flow between an inlet port 262
to the
tube and a plurality of outlet ports 264 from the tube. The inlet port may
have a
diameter larger than the diameter of each individual outlet port 264. The
diffuser tube
may be formed with an elbow 266 along its conduit length such that flow
passing
therethrough is redirected and does not pass straight through. The elbow
creates the
wall positioned out of alignment, for example substantially orthogonally, to
the axis
xa (see Figure 7) of the orifice's lateral aperture 2261). The tube in one
embodiment is
L or T-shaped with an inlet portion 270, which is a length of the tube having
the inlet
port 262 at one end thereof and elbow 266 at the other end and one or more,
such as
for example two, arm portions 272 extending from the inlet portion at the
elbow,
Outlet ports 264 are positioned in the arm portions 272, but are spaced from
elbow
266. The outlet ports may be holes through the tubular wall forming the arm
portions
and/or may be holes at the end of the arm portions. The inner diameter of the
inlet
portion opens at the elbow into the inner diameters of the arm portions, Thus,
fluid
passing through the conduit of the tube enters through the inlet port and
impinges
against an end wall 266a at the bend of elbow 266. The end wall 266a causes
the
fluid to change direction and flow down arm portions 272.
In one embodiment, the diffuser tube is T-shaped with inlet portion 270
connected to
two arm portions at a T-shaped elbow. The diffuser tube may be substantially
symmetrical about the inlet portion.
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The diffuser is positioned on the outer surface of the wall of the tubular 212
adjacent
the orifice of nozzle 222 to receive the fluid passing from lateral aperture
226b. In
one embodiment, inlet port 262 is positioned substantially aligned with
lateral
aperture 226b. For example, inlet port 262 may be positioned such that its
center
point is axially aligned with axis xa of the nozzle's lateral aperture 226b.
Inlet port
262 may be flared and may taper across its inner diameter with depth into the
inlet
port. This flare causes the inlet port opening of the diffuser to be conically
formed
and creates a wider entry site to the diffuser. This ensures that most if not
all of the
fluid passing from lateral aperture 226b passes into the diffuser conduit 260.
The arm portions 272 extend from inlet portion 270. Since the diffuser is
positioned
on the wall of tubular 212, arm portions 272 may be curved to substantially
follow the
circumferential curvature of the tubular's wall. In one embodiment, the long
axis of
inlet portion 270 extends substantially in alignment with long axis xb of the
tubular
body 212 and arms 272 are attached to the inlet portion and are curved to
extend
around the circumferential curvature orthogonal to the long axis xb of the
tubular
body.
As noted above, outlet ports 264 are positioned in the arm portions 272. Ports
264
may be positioned in the end of the arm portions 272 and/or may be positioned
spaced
apart along the length of each arm portion. In one embodiment, the ports 264
are
positioned to direct the fluid passing therethrough into a particular area of
the tubular.
In one embodiment, for example, ports 264 are positioned in arm portions 272
such
that fluid exiting therefrom cannot flow directly along a straight line to the
exit
opening 218a on the tubular. For example, ports 264 can be positioned in arm
portions 272 such that fluid passing from the ports must change direction to
reach the
exit opening 218a. The ports, for example, may be oriented to face towards a
blocking structure such as towards the outer surface, the shield or another
diffuser.
Alternately, the ports may be positioned to expel fluid into counter or cross
flowing
fluid path or along a path not directly parallel to the exit path leading to
exit opening
218a. For example, if there are two diffuser tubes in the tubular, they may be
positioned such that their outlet ports 264 face each other. In the
illustrated
embodiment, for example, ports 264 are positioned in arm portions 272 on a
side that
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faces away from the exit path of the fluid. The ports open towards another
diffuser
and, in particular, toward ports 264 on that other diffuser. Additionally, at
least some
ports are angled up toward shield 216 and/or angled down toward surface 212b,
which
are the walls that define the upper and lower limits, respectively, of the
exterior fluid
chamber 218. As such, ports 264 in the illustrated embodiment, are positioned
to
expel fluid away from opening 218a into a counter flowing fluid path generated
by
fluid expelled from the opposite diffuser and upwardly or downwardly at an
angle to
impinge against the upper or lower limits of the chamber in which they are
installed.
While, the diffuser may be installed in the tubular to receive an outward flow
from
nozzle 222, a bypass opening may be provided to permit produced fluid to
bypass the
diffuser and enter the nozzle without first passing through the diffuser. The
fluid
may, therefore, enter the nozzle directly to flow inwardly into the inner
diameter
without flowing through the diffuser, In the illustrated embodiment, diffuser
conduit
260 is spaced from the nozzle such that there is an open space 280 between the
nozzle
and the inlet portion 270 of the diffuser. Produced fluid may flow through
opening
218a, into open space 280 and then enter nozzle directly to thereby flow
inwardly into
the inner diameter, while bypassing at least the arm portions and elbow, and
possibly
the entirety, of the diffuser. The bypass opening may take other forms such as
large
holes through the inlet portion, if the diffuser if attached directly adjacent
the nozzle.
In addition, if desired, the diffuser may be mounted in chamber 218 with gaps
282
between the upper and/or lower surfaces of the arm portions 272 and the shield
216
and/or surface 212b such that produced fluid can pass above and below the
diffuser to
enter the nozzle's orifice without flowing through the diffuser.
In spite of these gaps 282 and open space 280, diffuser 260 is installed to be
held
firmly in its position adjacent the nozzle. In one embodiment, there is a
mounting
block 286 that secures the diffuser in position between shield 216 and base
pipe 212.
In Figure 11, mounting block 286 is sandwiched and secured between the shield
and
the base pipe and in the tubular of Figure 12, mounting block 286 is installed
in a
recess 288 in the shield. In any event, the mode of installation such as the
use of
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mounting block 286 maintains gaps 282 and spacing at open space 280, to secure
the
diffuser against being pushed away from the nozzle by the force of the fluid
flow,
Diffuser 260, especially at inlet port 262, outlet ports 264 and elbow 266,
must
withstand a lot of erosive fluid force, As such, diffuser 260 may be
constructed of a
durable material similar to those used for the nozzle. While the use of such
material
may be costly, the amount of this material required for nozzle 222 and
diffuser 260,
may be small compared to the overall material requirements of the tubular.
These
parts, the nozzle and the diffuser can be installed in a tubular formed of
standard
construction materials.
The spacing between the diffuser and the nozzle may determine how much of the
nozzle's flow is treated via the diffuser and the force at which the fluid
enters the inlet
portion. This spacing may be varied as desired in the construction of the
tubular.
The tubulars of Figures 10 and 13 differ in a few respects including the shape
and
mode of installation of the mounting portion 286. These two embodiments also
show
two different installations for nozzle 222, wherein Figure 10 shows the nozzle
formed
as an integral component of the base pipe and Figure 13 shows the nozzle as an
insert
installed through a capped port, such as is described in Figure 3,
The previous description of the disclosed embodiments is provided to enable
any
person skilled in the art to make or use the present invention. Various
modifications
to those embodiments will be readily apparent to those skilled in the art, and
the
generic principles defined herein may be applied to other embodiments without
departing from the spirit or scope of the invention. Thus, the present
invention is not
intended to be limited to the embodiments shown herein, but is to be accorded
the full
scope consistent with the claims, wherein reference to an element in the
singular, such
as by use of the article "a" or "an" is not intended to mean "one and only
one" unless
specifically so stated, but rather "one or more". All structural and
functional
equivalents to the elements of the various embodiments described throughout
the
disclosure that are known or later come to be known to those of ordinary skill
in the
art are intended to be encompassed by the elements of the claims, Moreover,
nothing
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disclosed herein is intended to be dedicated to the public regardless of
whether such
disclosure is explicitly recited in the claims. For US patent properties, it
is noted that
no claim element is to be construed under the provisions of 35 USC 112, sixth
paragraph, unless the element is expressly recited using the phrase "means
for" or
"step for".
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