Note: Descriptions are shown in the official language in which they were submitted.
WO 2021/150353
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SUBMERSIBLE PUMP ASSEMBLY AND METHOD FOR USE OF SAME
TECHNICAL FIELD OF THE INVENTION
This invention relates, in general, to submersible pump assemblies and, in
particular,
to submersible pump assemblies for the removal of fluid mediums with low
viscosity, such as
water or light crude oil, during hydrocarbon production from a well, for
example.
BACKGROUND OF THE INVENTION
Without limiting the scope of the present invention, the background will be
described
in relation to aging hydrocarbon producing wells where water encroachment may
occur. In a
to healthy, optimally producing well, high pressure hydrocarbon or oil flow
has the ability to lift
this liquid to the surface. Over time, however, as the pressures in the
formation decline and
water production increases, the flow conditions change_ The reservoir pressure
may no longer
be sufficient to unload the well such that water accumulates in the lower
section of the well
forming a column which further retards hydrocarbon production_ Several pump-
based
solutions have been suggested to overcome the fluid accumulation problem and
restore the
flow rate of hydrocarbon producing wells. Plunger-type pump assemblies are
limited by travel
speed and typically operate in low pressure, lower production hydrocarbon
producing wells in
an advanced well life. Centrifugal-type pump assemblies are able to handle
high production
requests, but typically have a higher operational cost than plunger-type pump
assemblies.
Further, as mentioned, over time, as the pressures in the formation decline
and water
production increases, the flow conditions and pressure conditions change. In
existing pump
assemblies, a rotational speed of a drive unit may be adjusted to compensate
for the change in
pressure conditions at a cost to the pump assemblies efficiency. Accordingly,
there is a need
for improved submersible pump assemblies and method for use of the same that
efficiently
operate across different hydrocarbon producing wells over the life of the
hydrocarbon
producing well.
SUMMARY OF THE INVENTION
It would be advantageous to achieve a submersible pump assembly and method for
use
of same that would improve upon existing limitations in functionality. It
would also be
desirable to enable a mechanical-based solution that would provide enhanced
operational
efficiently across different producing wells or other environments requiring
the removal of
fluid mediums with low viscosity, such as water or light crude oil. To better
address one or
more of these concerns, a submersible pump assembly and method for use of the
same are
disclosed. In one aspect, some embodiments include a cylinder block having
cylinders and
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pistons. A drive shaft is rotatably supported in the cylinder block and
coupled to a drive unit.
An inclined leading plate is coupled to the pistons and the drive shaft such
that pistons are
configured to be axially driven in a reciprocating motion within the cylinders
upon rotation of
the inclined leading plate. A suction port and a pressure port are each
located in fluid
-5 communication with the cylinders. In one operational mode, the fluid medium
is transferred
from the suction port to the pressure port during the reciprocating motion of
the pistons, when
the pistons are actively pumping. In another operational mode, the fluid
medium is circulated
through the suction chamber.
In another aspect, some embodiments include a submersible pump assembly for
1() transference of a fluid medium with low viscosity is disclosed. In these
embodiments, the
submersible pump assembly includes multiple pump units co-axially aligned with
a common
drive shaft, a common suction chamber, and a common pressure chamber. Each of
the pump
units includes an active operational mode wherein the fluid medium is
transferred from the
common suction chamber to the common pressure chamber as well as an inactive
operational
is mode wherein the fluid medium is circulated through the common suction
chamber. Each of
the pump units is individually actuatable.
In a still further aspect, some embodiments include multiple pump units co-
axially
aligned with a common drive shaft. Each of the multiple pump units is
individually
controllable such that the multiple pumps are serially positioned and
controllable in parallel.
20 Each of the multiple pump units include a drive shaft, which is rotatably
supported in the
cylinder block and coupled to a drive unit. An inclined leading plate is
coupled to the pistons
and the drive shaft such that pistons are configured to be axially driven in a
reciprocating
motion within the cylinders upon rotation of the inclined leading plate. A
suction port and a
pressure port are each located in fluid communication with the cylinders.
These and other
25 aspects of the invention will be apparent from and elucidated with
reference to the
embodiments described hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the features and advantages of the
present
invention, reference is now made to the detailed description of the invention
along with the
3 0 accompanying figures in which corresponding numerals in the
different figures refer to
corresponding parts and in which:
Figure 1 is a schematic illustration depicting one embodiment of an onshore
hydrocarbon production operation employing a submersible pump assembly,
according to the
teachings presented herein;
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Figure 2 is a schematic illustration depicting one embodiment of the
hydrocarbon
production operation of figure 1 in a first stage of removing a fluid medium
with low viscosity;
Figure 3 is a schematic illustration depicting one embodiment of the
hydrocarbon
production operation of figure 1 in a second stage of removing a fluid medium
with low
-5 viscosity;
Figure 4 is a schematic diagram depicting one embodiment of the submersible
pump
assembly of figure 1; and
Figure 5 is a schematic diagram depicting a cross section of the submersible
pump
assembly of figure 4 taken along line 5-5.
DETAILED DESCRIPTION OF THE INVENTION
While the making and using of various embodiments of the present invention are
discussed in detail below, it should be appreciated that the present invention
provides many
applicable inventive concepts, which can be embodied in a wide variety of
specific contexts.
The specific embodiments discussed herein are merely illustrative of specific
ways to make
is and use the invention, and do not delimit the scope of the present
invention.
Referring initially to figure 1, therein is depicted one embodiment of a
submersible
pump assembly 10 being employed in an onshore hydrocarbon production operation
12, which
may be producing oil, gas, or a combination thereof, for example. A wellhead
14 is positioned
over a subterranean hydrocarbon formation 16, which is located below a surface
18. A
wellbore 20 extends through the various earth strata including the
subterranean hydrocarbon
formation 16. A casing string 24 lines the wellbore 20 and the casing string
24 is cemented
into place with cement 26. Perforations 28 provide fluid communication from
the
subterranean hydrocarbon formation 16 to the interior of the wellbore 20. A
packer 22
provides a fluid seal between a production tubing 30 and the casing string 24.
Composite
coiled tubing 34, which is a type of production tubing 30, runs from the
surface 18, wherein
various surface equipment 36 is located, to a fluid accumulation zone 38
containing a fluid
medium F having a low viscosity, such as hydrocarbons like oil or gas,
fracture fluids, water,
or a combination thereof. As shown, the submersible pump assembly 10 is
coupled to a lower
end 40 of the production tubing 30.
'50 Referring now to figure 2 and figure 3, as shown, the submersible
pump assembly 10
is positioned in the fluid accumulation zone 38 defined by the casing string
24 cemented by
the cement 26 within the wellbore 20. The submersible pump assembly 10 is
incorporated
into a downhole tool 50 connected to the lower end 40 of the production tubing
30 and, more
particularly, the submersible pump assembly 10 includes a housing 52 having a
drive unit 54
coupled by a coupling unit 56 to serially positioned pump units 58, 60, 62,
which are, in turn,
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coupled to an intervention unit 64 and a connector 66. The pump unit 58 may
include ports
68, 70. Similarly, the pump unit 60 may include ports 72,74 and the pump unit
62 may include
ports 76, 78. The various ports 68, 70, 72, 74, 76, 78 may be assigned various
inlet or outlet
functions or be sealed shut. It should be appreciated that a variety of pump
unit-configurations
-5 may be employed and number of pump units, as well as ports, may vary
depending on the
particular application that the submersible pump assembly 10 is assigned. By
way of example,
in one implementation, the pump units 58, 60, 62 may share a common inlet
port.
In operation, to begin the processes of transferring the fluid medium F, the
submersible
pump assembly 10 is positioned in the fluid accumulation zone 38. Initially,
as shown best in
figure 2, the submersible pump assembly 10 is completely submerged in the
fluid medium F,
which, as mentioned, may include hydrocarbons such as oil and/or gas, fracture
fluid, water,
or combinations thereof. The submersible pump assembly 10 is actuated and
selective
operation of one or more of the pump units 58, 60, 62 begins. As time
progresses, as shown
best in figure 3, the submersible pump assembly 10 pumps the fluid medium F,
which may be
a production fluid or a production inhibiting fluid, for example, to the
surface 18. The process
of pumping the fluid medium F continues until the submersible pump assembly 10
is stopped.
In some embodiments, the submersible pump assembly 10 includes modularity to
provide multiple pump units in a serial arrangement in a single volume
represented by the
housing 52. The serial arrangement of the multiple pump units, however,
provides for parallel
operation with concurrent use of the pump units 58, 60, 62 to ensure
redundancy. In particular,
selective operation of the pump units 58, 60, 62 achieve total available low
rate as well as a
variable flow rate through the selective application of ON/OFF states to each
of the pump units
58, 60, 62.
Referring now to figure 4 and figure 5, the submersible pump assembly 10 for
transference of the fluid medium F with low viscosity is depicted in
additional detail. As
previously discussed, the housing 52 includes a drive unit 54 coupled by a
coupling unit 56 to
serially positioned pump units 58, 60, 62, which are, in turn, coupled to an
intervention unit
64 and a connector 66, which, as shown, connects the submersible pump assembly
10 to the
production tubing 30. The intervention unit 64 may be co-axially aligned with
the pump units
'5o 58, 60, 62 and permit the fluid medium F to bypass the pump units 58, 60,
62 as shown by
arrow C. The housing 52 may include housing members for each of the drive unit
54 and
pump units 58, 60, 62. The pump units 58, 60, 62 are co-axially aligned with a
common drive
shaft 90. The common drive shaft 90 may permit each of the pump units 58, 60,
62 to have
its own drive shaft section with drive shaft sections united by special shape
joint couplings
and driven in a serial arrangement by the drive unit 54. The common drive
shaft 90 provides
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non-interfered power transmission to each of the pump units 58, 60. 62 via the
central shaft
hole for the common drive shaft 90. Each of the pump units 58, 60, 62 may be
the same with
respect to structure and function.
A suction chamber 92 and a pressure chamber 94 are each located in fluid
-5 communication with the pump units 58, 60, 62. The suction chamber 92 may
include
peripheral positioning and service each of the pump units 58, 60, 62 and
provide a common
suction chamber, which allows concurrent or parallel access by all of the pump
units to a low
pressure side of the fluid medium F being pumped. The suction chamber 92
includes an inlet
port 96 with respective connection ports 98, 100, 102 to each of the pump
units 58, 60, 62.
The inlet port 96 may be positioned in fluid communication with port 68, for
example. Each
of the pump units 58, 60, 62 include respective connection ports 105, 107, 109
to the suction
chamber 92. The pressure chamber 94 may also include peripheral positioning
and service
each of the pump units 58, 60, 62 and provide a common pressure chamber, which
allows
concurrent or parallel access by all of the pump units 58, 60, 62 to a high
pressure side of the
is fluid medium F being pumped. The pressure chamber 94 includes an outlet
port 101 with
respective connection ports 104, 106, 108 establishing fluid communication
from the pump
units 58, 60, 62 to the production tubing 30 at the connector 66. The suction
chamber 92 and
the pressure chamber 94 provide each of the pump units 58, 60, 62 access to
the fluid medium
F. As all of the pump units 58, 60, 62 share the common suction chamber 92 and
the common
pressure chamber 94, the number of pump units 58, 60, 62 may be modified as
required. That
is, any number of pump units 58, 60, 62 may be employed and the number of pump
units 58,
60, 62 employed will depend on the application. In one implementation, a pump
unit 58, 60,
62 may be designed with respect to available fluid medium F capacity, i.e.,
flow that can be
attained in combination with the drive unit rotational speed and the selected
suction chamber
cross-section. The common suction chamber 92 and the common pressure chamber
94 are
peripherally positioned and the size of the common suction chamber 92 and the
common
pressure chamber 94 defines the maximum possible pump unit flow rate of the
fluid medium
F.
By way of example and not by way of limitation, with respect to the pump unit
58, a
o cylinder block 120 has multiple cylinders, including, for example, cylinders
122, 124, formed
therein. The connection port 98 is connected to the suction chamber 92 to
provide fluid
communication to the cylinders 122, 124. The connection port 104 is also
located in fluid
communication with the cylinders 122, 124. The connection port 105 is located
in fluid
communication with the cylinders 122, 124 as well. A respective number of
pistons 126, 128
are slidably received in each of the cylinders 122, 124 and appropriately
sealed thereat. The
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common drive shaft 90 is rotatably supported in the cylinder block 120 and the
common drive
shaft 90 is coupled to, and under the power of, the drive unit 54. The
cylinder block 120 is
utilized to guide and support the pistons 126, 128. The cylinder block 120 may
have
equidistantly spaced bores serving as the cylinders 122, 124 to accept the
matching pistons
-5 126, 128. The cylinder block 120 may include low friction sliding bushings
that connect the
cylinder block 120 and the pistons 126, 128. Sets of seals may be
appropriately positioned
within the cylinder block 120. The pistons 126, 128 push the fluid medium
towards the
pressure chamber 94. In one implementation, each of the pistons 126, 128 have
circumferentially drilled holes that supply the fluid medium to the pistons
126, 128 from the
io suction chamber 92.
In one implementation, an inclined leading plate 130 is coupled to the pistons
126, 128
and the common drive shaft 90. The inclined leading plate 130 includes a tilt
angle alpha that
is selectively adjustable. Further, the inclined leading plate 130 is coupled
to the pistons 126,
128 such that the pistons 126, 128 are configured to be axially driven in a
reciprocating motion
is within the cylinders 122, 124 upon rotation of the inclined leading plate
130. A respective
number of two-ball links 132, 134 connect the inclined leading plate 130 to
the pistons 126,
128. The inclined leading plate 130 is secured in place by sealing member 136
and bearing
members 138 proximate an interface with the coupling unit 56. A retainer plate
140 is secured
to the inclined leading plate 130 with a bearing member 142. The two-ball
links 132, 134, in
20 turn, are secured to the inclined leading plate 130 at the retainer plate
140. The two-ball links
132, 134 are designed to transfer linear, reciprocating motion from the
retainer plate 140 to
the pistons 126, 128. The form of the two-ball links 132, 134 may be
conditioned by the
kinematic motion of the retainer plate 140 and the pistons 126, 128. As shown,
a lubrication
subsystem 144 may be co-located with the two-ball links 132, 134. In one
embodiment, the
25 lubrication subsystem reduces the friction between the pistons 126, 128,
the two-ball links
132, 134, and the inclined leading plate 130 at the retainer plate 140.
In one embodiment, the kinematic motion of the pistons 126, 128 is achieved
via a
properly selected geometry of the inclined leading plate 130. The angle of a
contact surface
with respect to the common drive shaft 90 connects the inclined leading plate
130 to the
30 retainer plate 140 and the pistons 126, 128. Total inclination of the
inclined leading plate 130
is limited by an inner diameter of the housing 52. The retainer plate 140 may
be designed to
hold and guide the two-ball links 132, 134 such that each of the two-ball
links 132, 134 may
freely rotate but still transmit axial force to the appropriate piston 126,
128. The sealing
member 136 may be designed to hold wear-resistant components and sealing
components that
35 prevent the fluid medium from contacting the inclined leading plate 130. In
this manner, the
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inclined leading plate 130 is lubricated by the lubrication subsystem 144.
Many low viscosity
fluids do not have sufficient lubricating properties for high-load conditions,
like the conditions
that may be found proximate the two-ball links 132, 134. Therefore, the
sealing and
lubrication components at the two-ball links 132, 134 ensure sufficient
lubrication when the
-5 pump unit 58 is being utilized with low viscosity fluid mediums.
Check valves 146, 148 are serially positioned within the cylinder block 120 at
the
cylinder 122 to service the piston 126. Similarly, check valves 150, 152 are
serially positioned
within the cylinder block 120 at the cylinder 122 to service the piston 126.
The check valves
150, 152 cooperate to prevent backpressure by opening during an intake stroke
and closing
during an exhaust stroke. A valve plate connection 154 is positioned at the
cylinder block 120
and secured to a valve plate 156 actuatable by a drive member 158. The valve
plate 156 may
be utilized to control the flow of the fluid medium F, on a pump unit-by-pump
unit basis, by
rotating the valve plate 156 by a predetermined angle via the driver member
158. For example,
in one embodiment, the valve plate 156 may be set to an arrangement whereby
the fluid
medium F is permitted to flow into the pressure chamber 94 during active
pumping.
Alternatively, the valve plate 156 may be set to an arrangement whereby the
fluid medium F
returns to the suction chamber 92, via the connection port 105, for example,
with respect to
the pump unit 58. It should be appreciated that the valve plate 156 includes
proper sealing
components to prevent any connection between the suction chamber 92 and the
pressure
chamber 94. By way of example, a sealing member 160 positioned at the junction
between
the pump unit 58 and the pump unit 60 prevents any leaking at the connection
between the
suction chamber 92 and the pressure chamber 94. Similarly, a sealing member
162 positioned
at the junction between the pump unit 60 and the pump unit 62 also prevents
any leaking at
the connection between the suction chamber 92 and the pressure chamber 94. A
connection
assembly 170 represents the flanges, gaskets, seals, and other physical
components that
connect the pump unit 58 to the coupling unit 56. Similarly, a connection
assembly 172 is
positioned between the pump unit 58 and the pump unit 60; a connection
assembly 174 is
positioned between the pump unit 60 and the pump unit 62; and a connection
assembly 176 is
positioned between the pump unit 62 and the intervention unit 64. The housing
52 of the
submersible pump assembly 10 also provides the space for communication lines,
control and
service lines, acquisition and data lines, and power lines. The size and
positioning of these
additional utilities does not diminish the strength of operation of the
submersible pump
assembly 10.
In an active pumping or active operational mode when the pistons 126, 128 are
active,
the fluid medium F is transferred from the connection port 98 at the suction
chamber 92 to the
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connection port 104 at the pressure chamber 94 during the reciprocating motion
of the pistons
126, 128. That is, the fluid medium F flows as shown by arrows A and arrows B.
On the
other hand, in an inactive pumping or inactive operational mode when the
pistons 126, 128
are circulating the fluid medium F, the fluid medium F is transferred from the
connection port
-5 98 at the suction chamber 92 through the cylinder block 120 and out of the
connection port
105 to the suction chamber 92, as shown by arrows A and arrows B'. During
active pumping,
the submersible pump assembly 10 generates flow of fluid medium F by creating
a positive
pressure difference between the suction side at the suction chamber 92 and the
pressure side
at the pressure chamber 94. The pressure difference is achieved by the radial
positioning of
io the moving pistons 126, 128 with an accompanying number of the check valve
pairs, such as
check valves 146, 148, 150, 152, that open and close in an alternating manner
to prevent the
pressurized fluid medium F from running back. That is, each of the check
valves 146, 148,
150, 152 prevents backpressure by, with respect to the pistons 126, 128,
opening during an
intake stroke and closing during an exhaust stroke. The design of the
submersible pump
is assembly 10 allows each pump unit 58, 60, 62 to selectively pump fluid
medium F into the
pressure sided at the pressure chamber 94 in an active operational mode or
circulate the fluid
medium F through the suction chamber 92 during an inactive operational mode
when the pump
units 58, 60, 62 are pumping to circulate the fluid medium F. During the
inactive pumping
mode, an individual pump unit 58, 60, 62 does not add anything to the total
pumping flow rate
20 since the fluid medium F is circulating to and from the suction chamber 92.
In this inactive
operational mode, a pump unit is not loaded and may be idle or redundant and
continue in this
mode of operation indefinitely.
The submersible pump assembly 10 presented herein functions to remove fluid
mediums with low viscosity, such as water or light crude oil, for example. As
discussed, the
25 submersible pump assembly 10 provides for installation in confined spaces
such as pipes,
below or above the ground level, near or at a remote location_ Optionally, the
submersible
pump assembly 10 may be utilized with other downhole tools, such as
hydrocarbon and solid
particle separators, sensors, and measuring devices, for example. Further, as
discussed, any
number of pump units 58, 60, 62 may be utilized in the submersible pump
assembly 10 to
30 provide redundancy as well as, through selectively actuation, calibration
of the fluid medium
transference required. Further, in instances of multiple pump units, like pump
units 58, 60,
62, each of the pump units 58, 60, 62, may individually and selectively
actuated to pump the
fluid medium F from the suction chamber 92 to the pressure chamber 94 or
circulate the fluid
medium F through the suction chamber 92.
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The order of execution or performance of the methods and techniques
illustrated and
described herein is not essential, unless otherwise specified. That is,
elements of the methods
and techniques may be performed in any order, unless otherwise specified, and
that the
methods may include more or less elements than those disclosed herein. For
example, it is
-5 contemplated that executing or performing a particular element before,
contemporaneously
with, or after another element are all possible sequences of execution.
While this invention has been described with reference to illustrative
embodiments,
this description is not intended to be construed in a limiting sense. Various
modifications and
combinations of the illustrative embodiments as well as other embodiments of
the invention,
io will be apparent to persons skilled in the art upon reference to the
description. It is, therefore,
intended that the appended claims encompass any such modifications or
embodiments.
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