U.S. patent application number 10/692564 was filed with the patent office on 2005-04-28 for orbital downhole separator.
Invention is credited to Hamid, Syed, Li, Liping, Michael, Robert K., Smith, Harry D. JR., Surjaatmadja, Jim B..
Application Number | 20050087336 10/692564 |
Document ID | / |
Family ID | 34522156 |
Filed Date | 2005-04-28 |
United States Patent
Application |
20050087336 |
Kind Code |
A1 |
Surjaatmadja, Jim B. ; et
al. |
April 28, 2005 |
Orbital downhole separator
Abstract
An orbital downhole separator for separating well fluids into
constituents of different specific gravities. Specifically, it is
designed to separate water from oil or gas. The apparatus comprises
a housing with a rotating member therein driven by a motor in the
housing. Well fluid flows through the rotating member and is
subjected to centrifugal force to separate the components. A flow
conditioner is used to facilitate separation. The invention
includes several different versions of the flow conditioner
including an impeller, a stator and controllers for controlling the
speed of the motor in response to signals related to the amount of
petroleum in the water.
Inventors: |
Surjaatmadja, Jim B.;
(Duncan, OK) ; Michael, Robert K.; (Frisco,
TX) ; Li, Liping; (Dallas, TX) ; Hamid,
Syed; (Dallas, TX) ; Smith, Harry D. JR.;
(Montgomery, TX) |
Correspondence
Address: |
JOHN W. WUSTENBERG
P.O. BOX 1431
DUNCAN
OK
73536
US
|
Family ID: |
34522156 |
Appl. No.: |
10/692564 |
Filed: |
October 24, 2003 |
Current U.S.
Class: |
166/105.5 ;
166/265 |
Current CPC
Class: |
B01D 17/0217 20130101;
B04B 1/00 20130101; B01D 2221/04 20130101; B01D 17/0214 20130101;
B01D 21/262 20130101; E21B 43/38 20130101; B04B 11/02 20130101;
B01D 17/12 20130101; B04B 9/10 20130101; B01D 17/00 20130101; B01D
17/0214 20130101; B01D 17/0217 20130101 |
Class at
Publication: |
166/105.5 ;
166/265 |
International
Class: |
E21B 043/00; E21B
043/38 |
Claims
What is claimed is:
1. A downhole fluid separator comprising: a housing adapted for
connection to a tool string; a cylinder rotatably disposed in the
housing and defining a flow passage therein; and a motor disposed
in the housing for rotating the cylinder, wherein fluid flowing
through the housing enters the flow passage and is subjected to
centrifugal force such that the fluid is separated into different
components having different specific gravities.
2. The separator of claim 1 further comprising a flow conditioner
for facilitating the separation of the fluid.
3. The separator of claim 2 wherein the flow conditioner comprises
an impeller adjacent to an inlet of the cylinder for pumping fluid
into the flow passage.
4. The separator of claim 3 wherein the impeller is attached to the
cylinder.
5. The separator of claim 2 wherein the flow conditioner comprises
a baffle disposed in the flow passage in the cylinder to reduce
slippage of fluid in the rotating cylinder.
6. The separator of claim 5 wherein the baffle is one of a
plurality of angularly spaced baffles.
7. The separator of claim 5 wherein the baffle extends
longitudinally through the cylinder.
8. The separator of claim 2 wherein: the cylinder defines an oil
port and a sand port therein; the flow conditioner comprises a cup
disposed adjacent to an end of the cylinder; the cup has a first
lip adjacent to the oil port; the cup has a second lip adjacent to
the sand port; the first and second lips define an annular water
passage therebetween; the first lip directs separated oil through
the oil port; the second lip directs separated sand mixed with
water through the sand port; and water is directed through the
water passage.
9. The separator of claim 8 wherein the first and second lips are
substantially concentric.
10. The separator of claim 2 wherein: the motor is a variable speed
motor; and the flow conditioner comprises: a sensor in
communication with separated water discharged from the cylinder,
wherein the sensor generates an oil concentration signal in
response to a concentration of oil in the discharged water; and a
controller connected to the motor for varying the speed of the
motor in response to the oil concentration signal compared to a
predetermined desired oil concentration in the discharged
water.
11. The separator of claim 10 wherein the controller is an adaptive
controller.
12. The separator of claim 10 wherein the controller is a PID
controller.
13. The separator of claim 2 wherein: the motor is a variable speed
motor; and the flow conditioner comprises: a valve in communication
with oil discharged from the cylinder to control the flow of the
oil; an actuator adapted for opening and closing the valve; a
sensor in communication with separated water discharged from the
cylinder, wherein the sensor generates an oil concentration signal
in response to a concentration of oil in the discharged water; and
a controller connected to the actuator, wherein the valve is
actuated in response to the oil concentration signal compared to a
predetermined desired oil concentration in the discharged water,
such that the flow of oil from the cylinder is controlled to vary
the time the fluid is in the cylinder and thereby correspondingly
varying the amount of oil separated from the water.
14. The separator of claim 2 wherein: the motor is a variable speed
motor; and the flow conditioner comprises a smart controller
connected to the motor for varying the speed of the motor in
response to a function of voltage and current signals from the
motor compared to a predetermined desired value of a function
corresponding to a water-cut.
15. The separator of claim 2 wherein the flow conditioner comprises
a stator adjacent to an inlet end of the cylinder.
16. The separator of claim 15 wherein the stator comprises a
plurality of vanes for starting rotation of the fluid as it enters
the cylinder.
17. The separator of claim 2 wherein: the cylinder defines a first
port and a second port therein; the flow conditioner comprises a
cup disposed adjacent to a discharge end of the cylinder; the cup
has a first lip adjacent to the first port; the cup has a second
lip adjacent to the second port; the first and second lips define
an annular passage therebetween; and a sensor is disposed adjacent
to the cup for measuring the capacitance of fluid flowing
thereby.
18. The separator of claim 17 wherein the sensor is a
capacitance-type sensor disposed adjacent to the first lip and
first port.
19. The separator of claim 17 wherein the sensor is a MEMS sensor
embedded in a surface of the cup facing the annular passage.
20. The separator of claim 17 wherein capacitance data from the
sensor is transmitted wirelessly using EM telemetry.
21. A downhole fluid separator comprising: a housing adapted for
connection to a tool string; a rotating member disposed in the
housing; a motor disposed adjacent to the housing and connected to
the rotating member, wherein fluid flowing through the rotating
member is subjected to centrifugal force such that the fluid is
separated into heavier and lighter components; and a flow
conditioner for facilitating the separation of the fluid in the
rotating member.
22. The separator of claim 21 wherein the flow conditioner
comprises an impeller adjacent to an inlet of a flow passage in the
rotating member for pumping fluid into the flow passage.
23. The separator of claim 22 wherein the impeller is attached to
the rotating member.
24. The separator of claim 21 wherein the flow conditioner
comprises a baffle disposed in a flow passage in the rotating
member to reduce slippage of fluid therein.
25. The separator of claim 24 wherein the baffle is one of a
plurality of angularly spaced baffles.
26. The separator of claim 24 wherein the baffle extends
longitudinally through the rotating member.
27. The separator of claim 21 wherein: the rotating member defines
an annular flow passage therein with an oil port and a sand port in
communication with the flow passage; the flow conditioner comprises
a cup disposed adjacent to an end of the rotating member; the cup
has a first lip adjacent to the oil port; the cup has a second lip
adjacent to the sand port; the first and second lips define an
annular water passage therebetween; the first lip directs separated
oil through the oil port; the second lip directs separated sand
mixed with water through the sand port; and water is directed
through the water passage.
28. The separator of claim 27 wherein the first and second lips are
substantially concentric.
29. The separator of claim 21 wherein: the motor is a variable
speed motor; and the flow conditioner comprises: a sensor in
communication with separated water discharged from the rotating
member, wherein the sensor generates an oil concentration signal in
response to a concentration of oil in the discharged water; and a
controller connected to the motor for varying the speed of the
motor in response to the oil concentration signal compared to a
predetermined desired oil concentration in the discharged
water.
30. The separator of claim 29 wherein the controller is an adaptive
controller.
31. The separator of claim 29 wherein the controller is a PID
controller.
32. The separator of claim 21 wherein: the motor is a variable
speed motor; and the flow conditioner comprises: a valve in
communication with oil discharged from the rotating member to
control the flow of the oil; an actuator adapted for opening and
closing the valve; a sensor in communication with separated water
discharged from the rotating member, wherein the sensor generates
an oil concentration signal in response to a concentration of oil
in the discharged water; and a controller connected to the
actuator, wherein the valve is actuated in response to the oil
concentration signal compared to a predetermined desired oil
concentration in the discharged water, such that the flow of oil
from the rotating member is controlled to vary the time the fluid
is in the rotating member and thereby correspondingly varying the
amount of oil separated from the water.
33. The separator of claim 21 wherein: the motor is a variable
speed motor; and the flow conditioner comprises a smart controller
connected to the motor for varying the speed of the motor in
response to a function of voltage and current signals from the
motor compared to a predetermined desired value of a function
corresponding to a water-cut.
34. The separator of claim 21 wherein the flow conditioner
comprises a stator adjacent to an inlet end of the rotating
member.
35. The separator of claim 34 wherein the stator comprises a
plurality of vanes for starting rotation of the fluid as it enters
the rotating member.
36. The separator of claim 21 wherein: the rotating member defines
a first port and a second port therein; the flow conditioner
comprises a cup disposed adjacent to a discharge end of the
rotating member; the cup has a first lip adjacent to the first
port; the cup has a second lip adjacent to the second port; the
first and second lips define an annular passage therebetween; and a
sensor is disposed adjacent to the cup for measuring the
capacitance of fluid flowing thereby.
37. The separator of claim 36 wherein the sensor is a
capacitance-type sensor disposed adjacent to the first lip and
first port.
38. The separator of claim 36 wherein the sensor is a MEMS sensor
embedded in a surface of the cup facing the annular passage.
39. The separator of claim 36 wherein capacitance data from the
sensor is transmitted wirelessly using EM telemetry.
Description
BACKGROUND
[0001] This invention relates to downhole separators used in oil
and gas wells, and in particular, to an orbital downhole separator
driven by an internal motor and having a flow conditioner to
improve fluid separation and control systems for such
separators.
[0002] Oil and/or gas wells quite often pass through a productive
strata the yield of which includes oil, gas and other valuable
products but also includes undesirable and unwanted constituents
such as salt water. In oil well production operations, relatively
large quantities of water are frequently produced along with the
valuable petroleum products. This is particularly true during the
latter stages of the producing life of a well. Bringing this water
to the surface and handling it there represents a significant
expense in lifting, separation and disposal.
[0003] Various methods have been employed for extracting the
valuable petroleum yield from the unwanted constituents. Some have
involved the pumping of the total yield of the well to the surface
and then using various methods for separating the valuable products
from the unwanted portion. In addition, the unwanted portion of the
yield, after having been pumped to the well surface and separated,
often has been pumped downwardly again through a remote wellbore
into a disposal layer. This, of course, also increases
expenses.
[0004] In some oil wells, the unwanted constituents can amount to
as much as 80% to 90% of the total formation yield. Accordingly, to
obtain a given volume of valuable petroleum from the well fluid,
eight or nine times the volume of the petroleum must first be
pumped to the surface and then separated from the unwanted portion.
As already noted, this process can be very slow and expensive.
Although the problem of producing substantially water-free oil from
the well reservoir may occur at any stage in the life of an oil
well, the proportion of water to valuable yield generally increases
with time as the oil reserves decline. Ultimately, when the lifting
cost of the combined petroleum and water constituents exceeds the
value of the recovered oil, abandonment of the well becomes the
only reasonable alternative.
[0005] Many procedures have been tried for producing water-free oil
from a formation that has a large quantity of water. For example,
the oil and water produced are pumped or otherwise flowed together
to the surface where they are treated to separate the petroleum
from the water. Since the volume of water is usually much greater
than that of the oil, the separator must handle large volumes of
fluid and therefore is correspondingly large and expensive.
Moreover, the water produced contains mineral salts which are
extremely corrosive, particularly in the presence of air. Also,
flowing the oil and water together upwardly through the well
sometimes forms emulsions that are difficult to break. Such
emulsions frequently must be heated in order to separate them even
when in the presence of emulsion-treating chemicals. The heating of
the large amount of water, as well as the small amount of oil
requires an expenditure of large amounts of energy, reducing the
net equivalent energy production from the well.
[0006] Water produced from deep formations within the earth
frequently contains large amounts of natural salts. For this
reason, the salt water brought to the surface cannot be disposed of
by allowing it to flow into surface drains or waterways. Relatively
small amounts of salt water can sometimes be disposed of by
draining into a slush pit or evaporation tank. The normally
required disposal method for large volumes of salt water, however,
is to introduce the water into a subsurface formation. This
requires a disposal well for receiving the produced salt water.
[0007] By returning the water to the same formation in this manner,
the water is disposed of and also acts as a re-pressurizing medium
or drive to aid in maintaining the bottomhole pressure for driving
the well fluids toward the producing well. But, in those areas
where producing wells are widely separated, the cost of drilling
disposal wells for each producing well is often prohibitive. In
such instances, it is necessary to lay a costly pipeline-gathering
network to bring all of the produced water to a central location,
or alternatively, to transport the produced water by trucks or
similar vehicles. Regardless of the method for transporting the
waste salt water from a producing well to a disposal well, the cost
of the disposal can be, and usually is, prohibitive. Furthermore,
fluids from subterranean reservoirs can have undesirable
characteristics such as creating excessive pressure and
super-heating of the fluids. If excessive pressure is present, then
surface equipment, such as a choke manifold, must be installed to
choke the flow pressure down to about 2,000 psi, a manageable
pressure. If a highly pressurized fluid depressurizes within a
short period of time, then a large portion of the gas is "flashed".
This reaction adversely affects the desirable petroleum from the
formation yield. In general, both well seals and surface equipment
suffer in the presence of excessive fluid pressure and heat. This
equipment is expensive in terms of maintenance and capital costs.
Thus, it is highly desirable to minimize these undesirable
characteristics of the well flow before being brought to the
surface.
[0008] Downhole separation of water from oil in a well is a
desirable approach for disposal of formation water in the well. It
eliminates or reduces the excessive costs discussed above required
to pump the water to the surface and dispose of it. Furthermore,
the greatly reduced environmental impact of the produced water is
another factor in making this approach attractive.
[0009] Earlier downhole separators are shown in U.S. Pat. Nos.
5,156,586; 5,484,383; and 6,367,547.
[0010] The use of downhole separators eliminates or reduces the
excessive costs discussed above to pump the water and dispose of
it. Furthermore, the greatly reduced environmental impact of the
produced water is another factor in making this approach
attractive.
[0011] Improvements of prior art separators are desirable to
further improve efficiency. The present invention includes a
separator with a rotating cylinder and a variety of flow
conditioners to increase the efficiency of the separator. One
embodiment of the present invention adds an impeller to pump the
fluid into an annulus to increase tangential fluid velocities. In
another, a stator is used to orient the fluid to enter the impeller
with a minimum of shearing action. In still another, baffles are
positioned in an annular space in the rotor to force the fluid to
rotate at the shaft velocity which will improve the separation
efficiency.
[0012] In another embodiment, a multi-lip cup designed to
facilitate multi-density substances so that they are separated into
different conduits is used.
[0013] In another embodiment, a smart controller is used to control
the speed of the motor to modulate the oil concentration in the
outlet water. This control function is achieved without the use of
a sensor for oil-concentration feedback by measuring the voltage
and the current of the motor. The voltage is a measure of the rotor
speed, and the current is a function of the applied torque. The
torque in turn varies with the water-cut (the ratio of water to
oil). By establishing the relationship between the torque and the
water-cut and the speed, the motor speed can be adjusted to operate
at the desired set point.
[0014] A further embodiment utilizes a speed control which has an
oil-in-water concentration sensor feedback in conjunction with a
conventional PID controller or an adaptive controller for the
control function. The motor speed is adjusted to achieve the oil
concentration in the out fluid stream on the water side. One way of
doing this includes using a valve on the downstream side of the
water side which is modulated to achieve the quality of the water
to be re-injected. A conventional controller is used to regulate
the valve in response to the operating conditions to obtain a
desired set-point of the oil content in the re-injection water. An
adaptive controller can also be used to control the speed of the
motor or the position of the valve using an adaptive algorithm for
the controller to drive the concentration of the oil to the desired
value.
SUMMARY
[0015] The present invention is a downhole separator designed to
separate components of well fluids within the well without the
necessity of pumping the fluids to the surface first. The separator
may be said to comprise a housing adapted for connection to a tool
string for use in a well, a cylinder rotatably disposed in the
housing and defining a flow passage therein, and a motor disposed
in the housing for rotating the cylinder, whereby fluid flowing
through the housing enters the flow passage and is subjected to
centrifugal force such that the fluid is separated into different
components having different specific gravities. The separator may
further comprise a flow conditioner for facilitating the separation
of the fluids. The invention includes several different flow
conditioners.
[0016] One version of the flow conditioner comprises an impeller
adjacent to the inlet of the cylinder for pumping fluid into the
flow passage. The impeller is preferably attached to the
cylinder.
[0017] In another embodiment, the flow conditioner comprises a
baffle disposed in the flow passage in the cylinder to reduce
slippage of fluid in the rotating cylinder. Preferably, the baffle
is one of a plurality of angularly spaced baffles which extend
longitudinally through the cylinder.
[0018] In another embodiment, the cylinder defines an oil port and
a sand port therein, and the flow conditioner comprises a cup
disposed adjacent to an end of the cylinder. The cup has a first
lip adjacent to the oil port and a second lip adjacent to the sand
port. The first and second lips define an annular water passage
therebetween, wherein the first lip directs separated oil through
the oil port, the second lip directs separated sand and water
mixture through the sand port, and water is directed through the
water passage. The first and second lips are preferably
substantially concentric.
[0019] In another embodiment, the motor is a variable speed motor,
and the flow conditioner comprises an oil-in-water sensor in
communication with separated water discharged from the cylinder,
the sensor generating an oil concentration signal in response to a
concentration of oil in the discharged water, and a controller
connected to the motor for varying the speed of the motor in
response to the oil concentration signal compared to a
predetermined desired oil concentration in the discharged water.
The controller may be, for example, an adaptive controller or a PID
controller.
[0020] In an additional embodiment where the motor is a variable
speed motor, the flow conditioner comprises a valve in
communication with oil discharged from the cylinder to control the
flow of the oil, an actuator adapted for opening and closing the
valve, an oil-in-water sensor in communication with separated water
discharged from the cylinder wherein the sensor generates an oil
concentration signal in response to a concentration of oil in the
discharged water, and a controller connected to the actuator
whereby the valve is actuated in response to the oil concentration
signal compared to a predetermined desired oil concentration in the
discharged water, such that the flow of oil from the cylinder is
controlled to vary the time the fluid is in the cylinder and
thereby correspondingly varying the amount of oil separated from
the water.
[0021] In still another embodiment, the motor is again a variable
speed motor, and the flow conditioner comprises a smart controller
connected to the motor for varying the speed of the motor in
response to a function of voltage and current signals from the
motor compared to a predetermined desired value of a function
corresponding to the water-cut.
[0022] Another version of the flow conditioner comprises a stator
adjacent to an inlet end of the cylinder. The stator preferably
comprises a plurality of vanes for starting rotation of the fluid
as it enters the cylinder.
[0023] In one more embodiment, the cylinder defines a first port
and a second port therein, and the flow conditioner comprises a cup
disposed adjacent to a discharge end of the cylinder. The cup has a
first lip adjacent to the first port, a second lip adjacent to the
second port, the first and second lips defining an annular passage
therebetween. This flow conditioner also comprises a sensor
disposed adjacent to the cup for measuring the capacitance of fluid
flowing thereby such that an operator can determine the separation
of the components of the fluid. Preferably, the sensor is a
capacitance-type sensor disposed adjacent to the first lip and
first port. One example of the sensor is a MEMS sensor embedded in
a surface of the cup facing the annular passage. Capacitance data
from the sensor may be transmitted wirelessly to the surface or
downhole controller, using telemetry, such as EM telemetry.
[0024] Stated in another way, the orbital downhole separator
comprises a housing adapted for connection to a tool string for use
in a well, a rotating member disposed in the housing, a motor
disposed adjacent to the housing and connected to the rotating
member whereby fluid flowing through the rotating member is
subjected to centrifugal force such that the fluid is separated
into heavier and lighter components, and a flow conditioner for
facilitating the separation of the fluid in the rotating
member.
[0025] Numerous objects and advantages of the invention will be
understood by those skilled in the art when the following detailed
description of the preferred embodiments is read in conjunction
with the drawings illustrating such embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIGS. 1A and 1B show a longitudinal cross section of an
orbital downhole separator of the present invention.
[0027] FIG. 2 illustrates an embodiment of an orbital downhole
separator with a rotating cylinder having baffles therein.
[0028] FIG. 3 is a cross-sectional view taken along lines 3-3 in
FIG. 2.
[0029] FIG. 4 illustrates the use of a multi-lip cup with the
orbital downhole separator.
[0030] FIG. 5 schematically shows how a feedback controller can be
used to control the speed of a motor in the separator.
[0031] FIG. 6 is a schematic of a valve-based speed control for the
motor.
[0032] FIG. 7 shows a schematic of a smart sensor system.
[0033] FIG. 8 shows an embodiment having a stator to increase
rotation of the fluid at the inlet of an impeller.
[0034] FIG. 9 illustrates a sensor for determining oil-in-water
concentration of the fluid.
[0035] FIG. 10 is a cross section taken along lines 10-10 in FIG.
1A.
DESCRIPTION
[0036] Referring now to the drawings and more particularly to FIGS.
1A and 1B, an orbital downhole separator of the present invention
is shown and generally designated by the numeral 10. Separator 10
generally comprises a housing 12 with a rotor 14 rotatably disposed
therein. Rotor 14 is driven by an electric motor 16.
[0037] Housing 12 comprises an upper adapter 18 with a central
opening 20 therethrough. Upper adapter 18 has an external thread 22
adapted for connection to an upper tool string portion 24. Upper
adapter 18 is attached to a tubular member 26 by a threaded
connection 28. A seal 30 provides sealing engagement between upper
adapter 18 and tubular member 26.
[0038] Housing 12 further comprises a lower adapter 32 attached to
tubular member 26 by a threaded connection 34. A seal 36 provides
sealing engagement between tubular member 26 and lower adapter 32.
Lower adapter 32 has an external thread 38 adapted for engagement
with a lower tool string portion 40 if desired. Lower adapter 32
further defines a central opening 42 therethrough.
[0039] Tubular member 26 defines a central opening 44 therethrough
which is in communication with central opening 20 in upper adapter
18 and central opening 42 in lower adapter 32.
[0040] A first upper seal housing 46 is disposed in central opening
44 of tubular member 26 adjacent to upper adapter 18. Below first
upper seal housing 46 is a first upper bearing 48 and a second
upper bearing 50 therein, and the first upper bearing 48 and second
upper bearing 50 are separated by an upper spacer 52. Below second
upper bearing 50 is a second upper seal housing 53.
[0041] Upper spacer 52 defines an upper flow passage 54
therethrough.
[0042] A lower bearing housing 56 is disposed in central opening 44
of tubular member 26 adjacent to lower adapter 32. Lower bearing
housing 56 has a first lower bearing 58 and a second lower bearing
60 therein, and the first lower bearing 58 and second lower bearing
60 are separated by a lower spacer 62.
[0043] Lower bearing housing 56 defines a lower flow passage 64
longitudinally therethrough.
[0044] A bearing shaft 66 is disposed through, and supported by,
first and second lower bearings 58 and 60. Bearing shaft 66 defines
a central opening 68 in an upper end thereof.
[0045] Rotor 14 comprises a stub shaft 72, a main shaft 74 and a
rotating cylinder 76 positioned around the stub shaft 72 and main
shaft 74. Main shaft 74 and a rotating cylinder 76 form a rotating
member within housing 12.
[0046] An upper end of main shaft 74 extends into, and is supported
by, first upper bearing 48 and second upper bearing 50. Seal 77
provides sealing engagement between main shaft 74 and first upper
seal housing 46 above first upper bearing 48, and seal 79 provides
sealing engagement between main shaft 74 and second upper seal
housing 53 below second upper bearing 50.
[0047] Stub shaft 72 extends into central opening 68 in bearing
shaft 66 and is connected thereto by a spline 78. Stub shaft 72
defines a central opening 80 therein into which a lower portion of
main shaft 74 extends. Main shaft 74 is attached to stub shaft 72
by a threaded connection 82. A seal 84 provides sealing engagement
between stub shaft 72 and threaded connection 82.
[0048] Main shaft 74 defines a central opening 86 therethrough. A
plurality of radially extending upper ports 88 are in communication
with central opening 86. A plurality of radially extending lower
ports 90 are also in communication with central opening 86.
[0049] Rotating cylinder 76 is attached to stub shaft 72 at
press-fit connection 92. By this connection and others previously
described, it will be seen by those skilled in the art that bearing
shaft 66, stub shaft 72, main shaft 74 and rotating cylinder 76
rotate together. Rotating cylinder 76 and main shaft 74 define an
annular flow passage 94 therebetween.
[0050] The present invention comprises a number of different flow
conditioners to improve the efficiency of the separations of the
fluids flowing therethrough. In FIG. 1A, the flow conditioner is
characterized by an impeller 96 at the upper end of rotating
cylinder 76. Impeller 96 is positioned in annular flow passage 94
and facilitates flow through the annular flow passage 94, as will
be further described herein.
[0051] At least one inlet port 100 is defined in tubular member 26
adjacent to impeller 96. Preferably, but not by way of limitation,
inlet ports 100 are substantially tangentially disposed as best
seen in FIG. 10.
[0052] Stub shaft 72 has a plurality of longitudinally extending
flow ports 102 therein which provide communication between lower
flow passage 64 and annular flow passage 94. A lower seal 104
provides sealing between rotating stub shaft 72 and stationary
tubular member 26 of housing 12.
[0053] A seal adapter 106 is mounted on main shaft 74 adjacent to a
shoulder 108 on the main shaft 74 below second upper seal housing
53. An upper seal 110 provides sealing engagement between seal
adapter 106 and tubular member 26. Another seal 112 provides
sealing engagement between seal adapter 106 and main shaft 74.
[0054] A channel 114 is formed in seal adapter 106 and is aligned,
and in communication, with upper ports 88 in main shaft 74. Channel
114 is also in communication with upper flow passage 54 in upper
spacer 52.
[0055] Motor 16 is positioned in central opening 20 of upper
adapter 18. Motor 16 is adapted to drive a coupler shaft 120 which
is connected to main shaft 74. In other words, coupler shaft 120
interconnects motor 16 and rotor 14. Wiring (not shown) connects
motor 16 to a source of electrical power (not shown). When motor 16
is energized, coupler shaft 120 is rotated which causes main shaft
74 and the other components of rotor 14 to be rotated within
housing 12.
[0056] A plurality of longitudinally extending holes 122 are
defined through motor 16, and it will be seen that these holes 122
are in communication with upper flow passage 54 in upper spacer
52.
[0057] In operation, separator 10 is made up on a tool string of
which upper tool string portion 24 and lower tool string portion 40
are components. This tool string assembly is lowered to the desired
location in the wellbore. When it is desired to start a separation
process for fluid in the well, motor 16 is actuated. Well fluid
enters separator 10 through inlet port 100, and the fluid is forced
into annular flow passage 94. The rotation of rotating cylinder 76
applies centrifugal force to the fluid in annular flow passage 94.
This causes the heavier water to be separated from the lighter oil
or gas. That is, the water and other higher density materials, such
as sand, are forced radially outwardly in annular flow passage 94,
and the oil or gas (lighter components) stays to the inside.
[0058] In the embodiment using impeller 96 as the flow conditioner,
the impeller 96 acts to drive the fluid in a tangential direction.
The pressure in the well annulus forces the oil or gas through
lower ports 90 in main shaft 74 so that it enters central opening
86 in the main shaft 74. The oil or gas is forced upwardly through
central opening 86, and it exits main shaft 74 through upper ports
88 therein. The oil or gas continues to flow upwardly through
central opening 44 in tubular member 26, upper flow passage 54,
holes 122, central opening 20 in upper adapter 18 and on up through
upper tool string portion 24 to the surface for recovery.
[0059] Water is forced through flow ports 102, central opening 44
below stub shaft 72, lower flow passage 64, central opening 42 in
lower adapter 32 and on down through lower tool string portion 40
for disposal in the well.
[0060] Referring now to FIGS. 2 and 3, a second flow conditioner in
the form of an improved rotating cylinder is shown and designated
by the numeral 76'. Rotating cylinder 76' is similar to rotating
cylinder 76 in that it has an outer cylinder 124 and an inner
cylinder 126 which define the previously mentioned annular flow
passage 94 therebetween. In improved rotating cylinder 76', a
plurality of longitudinal baffles 128 are disposed in annular flow
passage 94 and extend the length thereof.
[0061] The fluid may slip within rotating cylinder 76 (that is, it
may not rotate with the rotating cylinder 76 as much as desired)
because of the inertia of the fluid. In improved rotating cylinder
76', the fluid is forced to rotate within the rotating cylinder 76'
because the fluid is held between inner cylinder 126 and outer
cylinder 124 by baffles 128, thus reducing the potential for fluid
slip, and this improves the separation of the water from the oil or
gas.
[0062] Referring now to FIG. 4, a third flow conditioner is shown
which provides for the separation of sand from at least some of the
water. Again, most of the components are the same as in separator
10. However, at the lower end of a modified rotating cylinder 76",
a multi-lip cup 130 is disposed in annular flow passage 94.
[0063] Cup 130 has an inner lip 132 adjacent to lower ports 90 and
an outer lip 134 generally concentric with the inner lip 132. An
annular port 136 is defined between inner lip 132 and outer lip
134. Rotating cylinder 76" defines a plurality of radially disposed
ports 138 therein adjacent to outer lip 134.
[0064] If there is sand in the fluid to be separated, it is
sometimes desirable to separate this from the water and oil or gas.
Cup 130 facilitates this separation. As the components of the fluid
are subjected to the centrifugal force previously discussed, the
water and sand are forced outwardly from the lighter oil or gas.
Further, the sand will be forced outwardly against the wall of
rotating cylinder 76". As the separated fluid components flow
downwardly though annular flow passage 94, it will be seen that the
oil or gas will flow inside inner lip 132 and out lower ports 90 as
previously discussed. The sand, still mixed with some water, will
flow outside of outer lip 134 and out ports 138 in rotating
cylinder 76". The bulk of the water, with the sand now separated
therefrom, will flow downwardly through annular port 136. Thus, the
second embodiment allows handling of sand as well as water and oil
or gas. It will be seen by those skilled in the art that this use
of cup 130 could be used to accommodate fluids with other various
density components and is not limited to just sand, water and oil
or gas.
[0065] Referring now to FIG. 5 a fourth flow conditioner for
downhole orbital separator is shown schematically to include a
speed control 140 for a variable speed motor 16'. Speed control 140
comprises an oil-in-water sensor 142 in communication with the
water discharged from separator 10 after separation of the water
from the oil or gas. Sensor 142 sends an oil concentration signal
to a feedback controller 144. A conventional PID (proportional
integral derivative) controller could also be used.
[0066] The oil concentration signal is compared to a predetermined
maximum desired oil concentration level. The speed of motor 16' is
adjusted to achieve the desired oil concentration level as
necessary even though the mixture of water and oil or gas from the
well may vary. The amount of centrifugal force applied to the fluid
varies with the speed of motor 16'.
[0067] Referring to FIG. 6, a fifth flow conditioner in the form of
a valve-based control 150 for separator 10 is shown schematically.
A valve 152 is used on the downstream side of the water side which
is modulated to achieve the quality of the water to be re-injected
into the well. A conventional controller 154 receives an oil
concentration signal from an oil-in-water sensor 156 and compares
it to a predetermined desired level. Controller 154 then sends an
actuator signal to a valve actuator 158 to regulate valve 152 to
vary the flow therethrough. Controlling the rate at which water is
discharged from separator 10 affects how long it is subjected to
the centrifugal force. Thus, the desired oil content in the water
is achieved.
[0068] It will be seen by those skilled in the art that speed
control 140 can be combined with valve-based control 150 using an
adaptive algorithm to control both the speed of motor 16' and the
actuation of valve 152.
[0069] Now referring to FIG. 7, a sixth flow conditioner
characterized by a smart sensor/controller 160 is illustrated
schematically for controlling separator 10. Like speed control 140
of the third embodiment, smart sensor/controller 160 controls the
speed of a variable speed motor 16' in separator 10 to achieve the
desired oil concentration level in the water. However, with smart
sensor/controller 160 an oil-in-water sensor is not required. The
voltage, V, and current, I, of motor 16' are measured. The voltage,
V, is a function of the speed of the rotor in the motor 16', and
the current, I, is a function of the applied torque on the rotor.
The torque in turn varies with the amount of separation of water
from the oil or gas (the water-cut). By establishing the
relationship between the torque and the water-cut and the speed of
motor 16', the speed of the motor 16' can be adjusted to operate at
the desired speed.
[0070] Referring now to FIG. 8, a seventh flow conditioner in a
separator 10'" is shown. Separator 10'" is substantially the same
as separator 10 except that a stationary stator 164 is used
adjacent to a rotating cylinder 76'". Stator 164 has a plurality of
vanes 166 which direct flow to rotating cylinder 76'" in a
tangential direction to force the fluid to start rotating before it
actually enters the rotating cylinder 76'" which enhances fluid
separation. In other words, stator 164 starts the fluid rotating
before it enters rotating cylinder 76'". Stator 164 could be used
in conjunction with impeller 96.
[0071] Referring now to FIG. 9 an eighth flow conditioner is shown
using a sensor 170 to measure the capacitance of the fluid to
determine the quality of the separation of the water from the oil
or gas. Sensor 170 is used in conjunction with previously described
cup 130. Sensor 170 may be a capacitance-type sensor to measure the
capacitance of the fluids in annular space 172 in cup 130.
Alternatively, a MEMS (micro electromechanical systems) sensor 174
may be embedded in surface 176 of cup 130 to measure the local
capacitance of an oil film that forms there. The capacitance data
may be transmitted wirelessly using EM telemetry or through some
commutation scheme.
[0072] Those skilled in the art will see that the different flow
conditioners of the present invention can be combined in various
ways to provide even more controlled separation.
[0073] It will be seen, therefore, that the separator 10 of the
present invention and the various flow conditioners thereof are
well adapted to carry out the ends and advantages mentioned as well
as those inherent therein. While preferred embodiments of the
invention have been shown for the purposes of this disclosure,
numerous changes in the arrangement and construction is well
adapted to carry out the ends and advantages of parts may be made
by those skilled in the art. All such changes are encompassed
within the scope and spirit of the appended claims.
* * * * *