Note: Descriptions are shown in the official language in which they were submitted.
PATENT
0256.0003
SELF-CLEANING SAND SCREEN
Cross-Reference to Related Applications
[0001] This application claims priority to U.S. Provisional Patent Application
No. 62/531,483,
filed on July 12, 2017, the entirety of which is incorporated by reference.
Background
[0002] Sand is found in oil, gas, and water being produced from active wells.
The sand can
originate in the formation itself or be introduced into the formation during
the hydraulic fracturing
of the well (e.g., as proppant sand). The sand causes damage to the well site
equipment and pipe
line, and, therefore, many jurisdictions require sand control. Oil and gas
wells are increasingly
utilizing sand separators such as screens/filters.
[0003] One way to ensure that sand of a certain size is being captured is to
employ a sand screen
(also known as a sand filter). The sand screen is a device that has slots or
holes of a certain size
so that no particles larger than that slot width can pass through the device.
The device is not well-
suited for bulk sand removal because the screen tends to plug-up when the
fluid includes large
amounts of sand. As such, these devices are often employed in series or after
another type of bulk
removal device such as a sedimentation unit. The primary devices work well at
removing most of
the sand but lose effectiveness as they fill/plug-up with sand.
[0004] As particles plug the slots of the sand screen, and the flow becomes
restricted, the
differential pressure caused by the filter increases. As a result, production
can ultimately decrease.
In many cases, paraffin waxes, that are not removed by the initial stage
separator, add to the
problem. To reverse these effects, the flow is shut-off to the unit, and the
filters are removed and
manually cleaned by workers. The disassembly, filter removal, washing, and
reassembly is a time-
consuming and labor-intensive task and has significant danger due to trapped
sour gas. Therefore,
there is a need for an automated solution of cleaning the sand filters.
Summary
[0005] An apparatus for removing sand from a well fluid is disclosed. The
apparatus includes a
pressure vessel having an inlet and an outlet. The well fluid flows into the
pressure vessel through
the inlet and flows out of the pressure vessel through the outlet. A screen is
positioned at least
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partially within the pressure vessel and configured to remove the sand from
the well fluid. At least
a portion of the sand that is removed from the well fluid at least partially
obstructs one or more
openings in the screen. A cleaning assembly is positioned at least partially
between the pressure
vessel and the screen and configured to remove the sand that is obstructing
the one or more
openings in the screen during a screen-cleaning operation.
[0006] In another embodiment, the apparatus includes a pressure vessel having
an inlet and an
outlet. The well fluid flows into the pressure vessel through the inlet and
flows out of the pressure
vessel through the outlet. A screen is positioned at least partially within
the pressure vessel. The
screen is substantially cylindrical and has a central longitudinal axis
extending therethrough. The
screen is configured to remove the sand from the well fluid. At least a
portion of the sand that is
removed from the well fluid at least partially obstructs one or more openings
in the screen. A
cleaning assembly is positioned at least partially between the pressure vessel
and the screen. The
cleaning assembly includes a power device configured to rotate the screen
about the central
longitudinal axis. The cleaning assembly also includes a spray nozzle that is
configured to spray
a washing fluid radially-inward onto the outer surface of the screen as the
power device rotates the
screen.
[0007] A method of removing sand from a screen disposed in a pressure vessel
is also disclosed.
The method includes causing a well fluid to flow into the pressure vessel. A
screen in the pressure
vessel removes the sand from the well fluid. At least a portion of the sand
that is removed from
the well fluid at least partially obstructs one or more openings in the
screen. The method also
includes removing the sand from the screen using a cleaning assembly that is
positioned at least
partially between the pressure vessel and the screen. The method also includes
rotating the screen
about a central longitudinal axis that extends therethrough as the sand is
removed from the screen.
Brief Description of the Drawings
[0008] The present disclosure may best be understood by referring to the
following description
and accompanying drawings that are used to illustrate embodiments of the
invention. In the
drawings:
[0009] Figure 1 illustrates a cross-sectional side view of a sand screen
assembly with a self-
cleaning assembly in a horizontal orientation, according to an embodiment.
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[0010] Figure 2 illustrates a cross-sectional side view of a power section of
the self-cleaning
assembly, according to an embodiment.
[0011] Figure 3 illustrates a perspective view of the self-cleaning assembly,
according to an
embodiment.
[0012] Figure 4 illustrates a cross-sectional side view of the power section
of the self-cleaning
assembly, according to an embodiment.
[0013] Figure 5 illustrates a cross-sectional side view of a support section
of the self-cleaning
assembly, according to an embodiment.
[0014] Figure 6 illustrates a perspective view of a cleaning device of the
self-cleaning assembly,
according to an embodiment.
[0015] Figure 7 illustrates an enlarged view of a nozzle manifold, according
to an embodiment.
[0016] Figure 8 illustrates a perspective view of another sand screen assembly
with a self-
cleaning assembly in a vertical orientation, according to an embodiment.
[0017] Figure 9 illustrates a transparent perspective view of a portion of the
sand screen
assembly (e.g., a sand screen casing) with the self-cleaning assembly from
Figure 8, according to
an embodiment.
[0018] Figure 10 illustrates a portion of the wash bar and nozzles from Figure
9, according to an
embodiment.
[0019] Figure 11 illustrates a screen from the sand screen assembly with the
self-cleaning
assembly from Figure 8, according to an embodiment.
[0020] Figure 12 illustrates the sand screen casing from Figure 9 with the
screen positioned
therein, according to an embodiment.
[0021] Figure 13 illustrates a top head and motor assembly from the sand
screen assembly with
the self-cleaning assembly from Figure 8, according to an embodiment.
[0022] Figure 14 illustrates a flowchart of a method for cleaning the sand
screen using the self-
cleaning assembly, according to an embodiment.
Detailed Description
[0023] The following disclosure describes several embodiments for implementing
different
features, structures, or functions of the invention. Embodiments of
components, arrangements,
and configurations are described below to simplify the present disclosure;
however, these
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embodiments are provided merely as examples and are not intended to limit the
scope of the
invention. Additionally, the present disclosure may repeat reference
characters (e.g., numerals)
and/or letters in the various embodiments and across the Figures provided
herein. This repetition
is for the purpose of simplicity and clarity and does not in itself dictate a
relationship between the
various embodiments and/or configurations discussed in the Figures. Moreover,
the formation of
a first feature over or on a second feature in the description that follows
may include embodiments
in which the first and second features are formed in direct contact, and may
also include
embodiments in which additional features may be formed interposing the first
and second features,
such that the first and second features may not be in direct contact. Finally,
the embodiments
presented below may be combined in any combination of ways, e.g., any element
from one
exemplary embodiment may be used in any other exemplary embodiment, without
departing from
the scope of the disclosure.
[0024] Additionally, certain terms are used throughout the following
description and claims to
refer to particular components. As one skilled in the art will appreciate,
various entities may refer
to the same component by different names, and as such, the naming convention
for the elements
described herein is not intended to limit the scope of the invention, unless
otherwise specifically
defined herein. Further, the naming convention used herein is not intended to
distinguish between
components that differ in name but not function. Additionally, in the
following discussion and in
the claims, the terms "including" and "comprising" are used in an open-ended
fashion, and thus
should be interpreted to mean "including, but not limited to." All numerical
values in this
disclosure may be exact or approximate values unless otherwise specifically
stated. Accordingly,
various embodiments of the disclosure may deviate from the numbers, values,
and ranges disclosed
herein without departing from the intended scope. In addition, unless
otherwise provided herein,
"or" statements are intended to be non-exclusive; for example, the statement
"A or B" should be
considered to mean "A, B, or both A and B."
[0025] In general, embodiments of the present disclosure provide an apparatus
for a self-cleaning
sand filtration device. Turning now to the specific, illustrated embodiments,
Figure 1 illustrates a
cross-sectional side view of a sand screen assembly 100 with a self-cleaning
assembly 200 in a
horizontal orientation. The sand screen assembly 100 includes a pressure
vessel 115 that is
configured to house a screen 110. The pressure vessel 115 may be configured to
withstand
pressures from about 1000 psi to about 10,000 psi (e.g., 3000 psi to about
5000 psi).
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[0026] The sand screen assembly 100 further includes an inlet 120 and an
outlet 105. As shown,
the screen 110 is disposed between the inlet 120 and the outlet 105. The
screen 110 is configured
to block, separate, or otherwise remove particles (e.g., sand) from a fluid
that flows into the inlet
120. The fluid may be a well fluid including oil, gas, water, or a combination
thereof (e.g., from
a well in a subterranean formation). The fluid may have a pressure from about
1000 psi to about
10,000 psi (e.g., 3000 psi to about 5000 psi). Once the particles have been
removed from the fluid,
the now-clean fluid, may flow out of the outlet 105. In one embodiment, the
screen 110 is a hollow,
cylindrical-shaped screen. The screen 110 may be similar to the screen
described in U.S. Patent
Publication No. 2015/0292313, which is incorporated herein by reference. As
described in greater
detail below, the self-cleaning assembly 200 may be positioned at least
partially within the pressure
vessel 115 and be configured to clean the screen 110 (e.g., remove particles
from the screen 110)
while positioned at least partially within the pressure vessel 115.
[0027] Figure 2 illustrates a cross-sectional side view of a power section 230
of the self-cleaning
assembly 200. The power section 230 includes a power device 205, such as a
hydraulic motor, an
electric motor, or a rotary actuator. The power device 205 is configured to
rotate the screen 110
along/around a central longitudinal axis 111 that extends through the (e.g.,
cylindrical) screen 110.
The power section 230 further includes a bearing member 210 that is configured
to maintain
alignment between a screen coupling 225 and a power coupling 235, while
allowing the screen
110 to rotate with respect to the pressure vessel 115.
[0028] Figure 3 illustrates a perspective view of the self-cleaning assembly
200 in the sand
screen assembly 100. The self-cleaning assembly 200 includes a cleaning device
250 positioned
adjacent to the screen 110. The cleaning device 250 is configured to clean the
screen 110 (e.g., as
the screen 110 is rotated by the power device 205). The self-cleaning assembly
200 includes an
optional linear actuator 220 that moves the cleaning device 250 in a
linear/axial direction that is
parallel to the central longitudinal axis 111 extending through the screen
110. In other words, the
cleaning device 250 may be reciprocated back and forth along an exterior
surface of the screen
110 as the screen 110 is rotated by the power device 205. In one embodiment,
the linear actuator
220 is a hydraulic cylinder or a pneumatic cylinder. In another embodiment,
the linear actuator
220 is a rotating screw drive. In yet another embodiment, the cleaning device
250 does not move
relative to the screen 110 in the linear/axial direction.
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[0029] In the embodiment shown in Figure 3, the cleaning device 250 is a spray
nozzle assembly.
During a screen-cleaning operation, the spray nozzle assembly is configured to
spray a washing
fluid, such as water, anti-freeze, cleaner-degreaser, etc. on the exterior
surface of the screen 110
to clean/remove the particles that are on and/or in the screen 110. In other
embodiments, the
cleaning device 250 may be linear brush and/or a linear scrapper that is/are
configured to
physically brush or scrape particles off of the screen 110.
[0030] Figure 4 illustrates a cross-sectional side view of the power section
230 of the self-
cleaning assembly 200. As shown, the linear actuator 220 is disposed adjacent
the power device
205 of the power section 230.
[0031] Figure 5 illustrates a cross-sectional side view of a support section
240 of the self-
cleaning assembly 200. The support section 240 is configured to support an end
of the screen 110
as the screen 110 rotates around its longitudinal axis 111. The support
section 240 includes a
bearing 280 (or bushing) that allows the screen 110 to be supported while
rotating. The support
section 240 further includes a seal member 245 disposed between the bearing
280 and the screen
110. The seal member 245 is configured to seal a fluid path between the
bearing 280 and the
screen 110 such that fluid (arrow 285) exits the screen 110 of the sand screen
100.
[0032] Figure 6 illustrates a perspective view of the cleaning device 250 of
the self-cleaning
assembly 200. In the embodiment shown, the cleaning device 250 may be or
include a spray
nozzle assembly that is configured to spray the washing fluid on the exterior
surface of the screen
110. The spray nozzle assembly includes a plurality of spray nozzles 265
connected to a nozzle
manifold 260. The nozzle manifold 260 is connected to a manifold feed hose
255. The manifold
feed hose 255 may be connected to a skid mounted water pump (not shown) which
is configured
to supply the washing fluid to the cleaning device 250.
[0033] Figure 7 illustrates an enlarged view of the nozzle manifold 260. In
the embodiment
shown, there are four spray nozzles 265 connected the nozzle manifold 260. In
other embodiments,
any number of spray nozzles 265 may be connected to the nozzle manifold 260
without departing
from the present disclosure. Each nozzle manifold 260 is fed by the manifold
feed hose 255 that
runs to the exterior of the pressure vessel 115. A control valve (not shown)
is attached to the
cleaning device 250 and is configured to allow the first set of spray nozzles
to spray for a
predetermined time to ensure the linear actuator 220 has completed a full
cycle (e.g., moving the
cleaning device back and forth as described herein). The valve is then
switched/actuated, and the
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next nozzle manifold is pressurized to spray for a predetermined amount of
time to ensure the next
portion of the screen is cleaned. The steps are repeated until the entire
screen 110 is cleaned.
[0034] Figure 8 illustrates a perspective view of another sand screen assembly
800 with a self-
cleaning assembly 900 in a vertical orientation, according to an embodiment.
The sand screen
assembly 800 and/or the self-cleaning assembly 900 may be similar to the sand
screen assembly
100 and/or the self-cleaning assembly 200, except the sand screen assembly 800
and/or the self-
cleaning assembly 900 may be in a vertical orientation. In other words, a
central longitudinal axis
811 through the sand screen assembly 800 and/or the self-cleaning assembly 900
may be vertical.
[0035] The sand screen assembly 800 may include a pressure vessel 815, an
inlet 820, an outlet
805, and a drain 825. The self-cleaning assembly 900 may include a hydraulic
motor 905, an
electric motor 910, and a hydraulic pump 915.
[0036] The fluid with particles (e.g., sand) dispersed therein may flow into
the pressure vessel
815 through the inlet 820. The fluid may then flow (e.g., radially) inward
through the screen 810
(see Figure 11), which is positioned inside the pressure vessel 815. Particles
having a larger cross-
section (e.g., diameter) than the openings in the screen 810 may be prevented
from flowing (e.g.,
radially) inward through the screen 810. In at least one embodiment, the
openings in the screen
810 may be 150 microns. Thus, the screen 810 may filter/clean the fluid. The
now-clean fluid
may flow axially through the screen 810 and exit the pressure vessel 815
through the outlet 805.
At least a portion of the particles may descend through the annulus between
the pressure vessel
815 and the screen 810 to a lower axial end 816 of the pressure vessel 815.
However, a portion of
the particles may become caked-onto the outer surface of the screen 810,
plugging at least a portion
of the openings in the screen 810. As described in greater detail below, the
self-cleaning assembly
900 may remove the particles that are caked-onto the outer surface of the
screen 810 so that these
particles may also descend through the annulus between the pressure vessel 815
and the screen
810 to the lower axial end 816 of the pressure vessel 815.
[0037] When the particles are removed from the outer surface of the screen 110
in the sand
screen assembly 100 by the self-cleaning assembly 200 shown in Figure 1 (e.g.,
in the horizontal
orientation), the particles may fall to the inner radial surface of the
pressure vessel 115. This may
mitigate the benefits of cleaning the screen 110, as the particles on the
inner radial surface of the
pressure vessel 115 may partially obstruct a relatively large portion of the
screen 110. However,
when the particles are removed from the outer surface of the screen 810 in the
sand screen
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assembly 800 by the self-cleaning assembly 900 in Figure 8 (e.g., in the
vertical orientation), the
particles may fall to the lower axial end 816 of the pressure vessel 815. This
may result in only
the lower end (and progressively more, as more sand is removed) of the screen
810 being
obstructed by the sand, and thus less surface area when comparing equal
amounts of sand.
[0038] Figure 9 illustrates a transparent perspective view of a portion of a
sand screen casing
830 with the self-cleaning assembly 900, according to an embodiment. The sand
screen casing
830 may be positioned inside the pressure vessel 815, and the screen 810 may
be positioned inside
the sand screen casing 830. The fluid may flow through the inlet 820 of the
pressure vessel 815
and through an inlet of the sand screen casing 830. In at least one
embodiment, the orientation of
the inlet 820 of the pressure vessel 815 and/or the inlet of the sand screen
casing 830 may cause
the fluid to have a centrifugal flow between the sand screen casing 830 and
the screen 810, which
may provide a centrifugal separation (e.g., cyclone) effect. In at least one
embodiment, the sand
screen casing 830 may be optional/omitted.
[0039] The self-cleaning assembly 900 may include a manifold feed hose (e.g.,
a supply tubing)
955 for supplying the washing fluid (e.g., water) to a nozzle manifold (e.g.,
a wash bar) 960. The
self-cleaning assembly 900 may optionally include an auxiliary brush 980 that
may physically
brush/scrape the particles off of the outer surface of the screen 810, e.g.,
as the screen 810 is rotated
with respect to the brush 980, the sand screen casing 830, and/or the pressure
vessel 815. One or
more openings 832 may be provided at a lower end of the sand screen casing 830
that provide a
path of fluid communication from the main chamber to the screen 810.
[0040] Figure 10 illustrates a portion of the nozzle manifold 960, according
to an embodiment.
The nozzle manifold 960 may receive the washing fluid from the manifold feed
hose 955 and then
eject/spray the washing fluid out onto the outer surface of the screen 810
through one or more
nozzles 965. The nozzles 965 may be axially offset from one another along the
nozzle manifold
960.
[0041] Figure 11 illustrates the screen 810, according to an embodiment. The
screen 810 may
be a tubular member (e.g., a pipe) with the openings formed radially
therethrough. In at least one
example, the screen 810 may have a 6 inch diameter; however, as will be
appreciated other
diameters/sizes may also be used without departing from the disclosure. The
screen 810 may have
a coupling 812 at a first (e.g., upper) axial end. The coupling 812 may be a
female shaft coupling.
The screen 810 may have an outlet with seals 813 at a second (e.g., lower)
axial end.
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[0042] Figure 12 illustrates the sand screen casing 830 with the screen 810
positioned therein,
according to an embodiment. An outlet 834 of the screen 810 and/or the sand
screen casing 830
may be in communication with the outlet 805 of the sand screen assembly 800.
The outlet 834
may be made from chrome to prevent seizing.
[0043] Figure 13 illustrates a top head and motor assembly 905 of the self-
cleaning assembly
900, according to an embodiment.
[0044] Figure 14 illustrates a flowchart of a method 1400 for cleaning the
sand screen 800 using
the self-cleaning assembly 900, according to an embodiment. The method 1400 is
described with
reference to the sand screen 800 and the self-cleaning assembly 900 for
simplicity; however, as
will be appreciated, the method 1400 may also apply to the sand screen 100 and
the self-cleaning
assembly 200.
[0045] The method 1400 may include causing the fluid to flow into the sand
screen 800 through
the inlet 820, as at 1402. The user may cause the fluid to flow by, for
example, actuating a valve
that is in fluid communication with the inlet 820. The fluid may then flow
into the pressure vessel
815 and subsequently radially-inward through the openings in the screen 810 in
the pressure vessel
815. Particles with a dimension larger than the openings in the screen 810 may
be
separated/removed from the fluid by the screen 810 and remain in the annulus
between the screen
810 and the pressure vessel 815. In at least one example, a first portion of
the separated/removed
particles may remain adhered to (e.g., caked-onto) the outer surface of the
screen 810. The first
portion of the separated/removed particles may plug or otherwise obstruct the
openings in the
screen 810. A second portion of the separated/removed particles may descend
through the annulus
to the lower end 816 of the pressure vessel 815 (e.g., due to gravity).
[0046] The method 1400 may also include determining that the screen is at
least partially
obstructed, as at 1404. In at least one embodiment, determining that the
screen is at least partially
obstructed may include measuring a pressure of the fluid. More particularly,
one or more sensors
may be used to measure the pressure of the fluid at the inlet 820 and the
pressure of the fluid of
the outlet 805 to determine the pressure drop therebetween. The screen 810 may
be determined to
be at least partially obstructed by the particles when the pressure drop
exceeds a predetermined
amount. In one example, the operating pressure of the fluid may be greater
than or equal to about
500 psi (e.g., 3 ksi ¨ 10 ksi). In another embodiment, determining that the
screen is at least partially
obstructed may include measuring a volumetric flow rate. More particularly,
one or more sensors
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may be used to measure the volumetric flow rate of the fluid at the inlet 820
and/or the outlet 805.
The screen 810 may be determined to be at least partially obstructed by the
particles when the
volumetric flow rate drops below a predetermined amount.
[0047] The method 1400 may also include removing (e.g., the first portion of
the) particles from
the outer surface of the screen 810, as at 1406. The screen 810 may remain
positioned within the
pressure vessel 815 as the (e.g., first portion of the) particles are removed.
Removing the (e.g., the
first portion of the) particles may include spraying a washing fluid onto the
outer surface of the
screen with a spray nozzle assembly, as at 1408. More particularly, a valve
may be actuated to
cause the washing fluid to flow through the manifold feed hose 955, into the
nozzle manifold 960,
and out the nozzles 965. The washing fluid may be sprayed radially-inward from
the nozzles 965
onto the outer surface of the screen 810.
[0048] In at least one embodiment, removing (e.g., the first portion of the)
particles may also or
instead include rotating the screen 810, as at 1410. More particularly, the
hydraulic motor 905
and/or the electric motor 910 may rotate the screen 810 about the central
longitudinal axis 811 that
extends therethrough. This may help to ensure that the particles are removed
all portions of the
screen 810 (e.g., around the circumference).
[0049] In at least one embodiment, removing (e.g., the first portion of the)
particles may also or
instead include moving the nozzle manifold 960 within the pressure vessel 815,
as at 1412. More
particularly, the nozzle manifold 960 may be moved axially/longitudinally by
the hydraulic pump
915 in a direction that is parallel to the central longitudinal axis 811
through the screen 810. This
may help to ensure that the particles are removed all portions of the screen
810 (e.g., along the
length of the screen 810).
[0050] After the (e.g., first portion of the) particles are removed from the
screen 810, the (e.g.,
first portion of the) particles may descend through the annulus to the lower
end 816 of the pressure
vessel 815 (e.g., due to gravity). The now-clean fluid may exit the pressure
vessel 815 through
the outlet 805. The particles may be removed from the pressure vessel 815
through the drain 825.
[0051] As used herein, the terms "inner" and "outer"; "up" and "down"; "upper"
and "lower";
"upward" and "downward"; "above" and "below"; "inward" and "outward"; "uphole"
and
"downhole"; and other like terms as used herein refer to relative positions to
one another and are
not intended to denote a particular direction or spatial orientation. The
terms "couple," "coupled,"
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"connect," "connection," "connected," "in connection with," and "connecting"
refer to "in direct
connection with" or "in connection with via one or more intermediate elements
or members."
[0052] The foregoing has outlined features of several embodiments so that
those skilled in the
art may better understand the present disclosure. Those skilled in the art
should appreciate that
they may readily use the present disclosure as a basis for designing or
modifying other processes
and structures for carrying out the same purposes and/or achieving the same
advantages of the
embodiments introduced herein. Those skilled in the art should also realize
that such equivalent
constructions do not depart from the spirit and scope of the present
disclosure, and that they may
make various changes, substitutions, and alterations herein without departing
from the spirit and
scope of the present disclosure.
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