U.S. patent application number 11/617338 was filed with the patent office on 2008-01-10 for pump integrity monitoring.
Invention is credited to Sarmad Adnan, Nikolai Baklanov, Evgeny Khvoshchev.
Application Number | 20080006089 11/617338 |
Document ID | / |
Family ID | 39356532 |
Filed Date | 2008-01-10 |
United States Patent
Application |
20080006089 |
Kind Code |
A1 |
Adnan; Sarmad ; et
al. |
January 10, 2008 |
PUMP INTEGRITY MONITORING
Abstract
A method of monitoring integrity of a pump. The method may
include recording timing information of the pump during operation
while simultaneously sampling acoustic data with a high speed
equidistant acquisition mechanism or at a rate based on the speed
of the pump in operation. The acquisition of acoustic data is
followed by evaluation thereof. Such techniques may improve
resolution of acquired data while substantially increasing
processor capacity for evaluation. A pump integrity monitor for
carrying out such techniques is also described.
Inventors: |
Adnan; Sarmad; (Sugar Land,
TX) ; Khvoshchev; Evgeny; (Sugar Land, TX) ;
Baklanov; Nikolai; (Sugar Land, TX) |
Correspondence
Address: |
SCHLUMBERGER TECHNOLOGY CORPORATION;David Cate
IP DEPT., WELL STIMULATION, 110 SCHLUMBERGER DRIVE, MD1
SUGAR LAND
TX
77478
US
|
Family ID: |
39356532 |
Appl. No.: |
11/617338 |
Filed: |
December 28, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11482846 |
Jul 7, 2006 |
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11617338 |
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Current U.S.
Class: |
73/587 ; 417/63;
702/39; 73/168 |
Current CPC
Class: |
F04B 51/00 20130101;
F04D 15/0088 20130101; F04B 2201/0802 20130101; G01B 5/00 20130101;
G01M 3/24 20130101 |
Class at
Publication: |
73/587 ; 73/168;
702/39; 417/63 |
International
Class: |
G01N 29/14 20060101
G01N029/14; F04B 51/00 20060101 F04B051/00; F04B 23/04 20060101
F04B023/04 |
Claims
1. A method of monitoring integrity of a pump assembly, the method
comprising: operating the pump assembly; recording timing
information relative to said operating; sampling acoustic data with
a high speed acquisition mechanism of the pump assembly; and
evaluating the acoustic data in light of the timing
information.
2. The method of claim 1 wherein said sampling occurs at a rate of
more than about 100,000 samples of the acoustic data per
second.
3. The method of claim 2 wherein the high speed acquisition
mechanism is a high speed acquisition board of a pump integrity
monitor for said recording, said sampling and said evaluating.
4. The method of claim 1 wherein said evaluating further comprises
distinguishing acoustic data that represents a healthy pump
assembly condition from acoustic data that represents an unhealthy
pump assembly condition.
5. The method of claim 4 wherein the unhealthy condition is a
condition of one of pump mounts, a plunger, crankshaft bearings, a
transmission, a pump valve seal, valve spring, crossheads, pony
rods, and piston operation of the pump assembly.
6. The method of claim 4 wherein said distinguishing is achieved
with reference to a vibration signature pre-programmed into a
processor of the pump integrity monitor.
7. The method of claim 1 wherein said recording further comprises
monitoring a position of a moving part of the pump assembly.
8. The method of claim 7 wherein said monitoring is achieved with a
speed sensor coupled to a driveline mechanism of the pump
assembly.
9. The method of claim 1 wherein said operating of the pump
assembly is at a given speed, said sampling occurring at a rate
based on the given speed.
10. A method of monitoring integrity of a pump assembly, the method
comprising: operating the pump assembly; monitoring a speed of said
operating; sampling acoustic data from the pump assembly at a rate
based on the speed; and evaluating the acoustic data for
distinguishing acoustic data that represents a healthy pump
assembly condition from acoustic data that represents an unhealthy
pump assembly condition.
11. The method of claim 10 wherein the unhealthy condition is a
condition of one of pump mounts, a plunger, crankshaft bearings, a
transmission, a pump valve seal, valve spring, crossheads,
ponyrods, and piston operation of the pump assembly.
12. The method of claim 10 wherein said pump assembly includes a
crankshaft for rotation during said operating, said sampling
occurring at a rate of between about 50 and about 5,000 samples of
the acoustic data per rotation.
13. The method of claim 10 wherein said monitoring further
comprises tracking a position of a moving part of the pump
assembly.
14. The method of claim 13 wherein the pump assembly is a positive
displacement pump assembly and the moving part is a plunger, said
monitoring achieved with an index sensor coupled to a plunger
housing of the pump assembly, the plunger housing to accommodate
the plunger, the plunger having a collar detectable by the index
sensor.
15. The method of claim 10 wherein said evaluating occurs without
performing a discrete Fourier Transform conversion.
16. The method of claim 10 wherein said evaluating further
comprises analyzing acoustic data in frequencies between about 100
Hz and about 600 KHz.
17. The method of claim 10 wherein said evaluating occurs as the
speed varies.
18. The method of claim 10 wherein the distinguishing is achieved
with reference to a vibration signature loaded into a processor of
a pump integrity monitor for said monitoring, said sampling and
said evaluating.
19. The method of claim 10 wherein the distinguishing of data that
represents a healthy pump assembly condition includes recognizing
noise based on the speed.
20. The method of claim 10 wherein said sampling occurs at a rate
of more than about 100,000 samples of the acoustic data per
second.
21. The method of claim 10 wherein said sampling takes place at one
of a constant sampling rate and a variable sampling rate.
22. A pump integrity monitor comprising: a processor; a speed
sensor coupled to said processor for monitoring a speed of an
operating pump assembly; and a data sensor coupled to said
processor for sampling harmonic data from the pump assembly at a
rate based upon the speed.
23. The pump integrity monitor of claim 22 wherein said speed
sensor is one of an index sensor and a proximity switch for
tracking a position of a moving part of the pump assembly.
24. The pump integrity monitor of claim 22 wherein said data sensor
is coupled to said processor via a high speed acquisition board to
acquire the harmonic data at a rate of more than about 100,000
samples per second.
25. The pump integrity monitor of claim 22 wherein said data sensor
is one of an accelerometer coupled to the operating pump and a
pressure transducer coupled to a fluid line for receiving fluid
pumped by the operating pump.
26. The pump integrity monitor of claim 25 wherein said data sensor
is a first data sensor, the pump integrity monitor further
comprising a second data sensor that is one of the accelerometer
and the pressure transducer, harmonic data from each of the first
and second data sensor to be simultaneously analyzed and
correlated.
27. A pump assembly comprising: a pump; a pump integrity monitor
having a speed sensor coupled to said pump for monitoring a speed
thereof during operation thereof; and an acoustic sensor coupled to
said pump integrity monitor for sampling acoustic data at a rate
based upon the speed.
28. The pump assembly of claim 27 further comprising a processor
coupled to said pump integrity monitor for distinguishing acoustic
data that represents a healthy pump assembly condition from
acoustic data that represents an unhealthy pump assembly
condition.
29. The pump assembly of claim 28 wherein the unhealthy condition
is a condition of one of engine mounts, a plunger, crankshaft
bearings, a transmission, a pump valve seal, and piston
operation.
30. The pump assembly of claim 27 wherein said pump is a positive
displacement pump and comprises a crankshaft for rotation during
operation, the sampling to occur at a rate of between about 50 and
about 5,000 samples of the acoustic data per rotation.
31. The pump assembly of claim 30 wherein said pump further
comprises: a plunger having a detectable collar secured thereto,
said plunger coupled to said crankshaft; and a fluid housing to
accommodate said plunger therein, the speed sensor coupled to said
fluid housing and being an index sensor for detecting a position of
the detectable collar as said crankshaft reciprocates said plunger
during the rotation.
32. The pump assembly of claim 27 wherein said pump is one of a
positive displacement pump, a centrifugal pump, a triplex pump, a
fracturing pump, a cementing pump, a coiled tubing pump, and a pump
for water jet cutting.
33. The pump assembly of claim 27 further comprising: an engine for
driving operation of said pump; a transmission coupled to said pump
and said engine for directing the driving; and a platform securing
said engine, said transmission, said pump and said pump integrity
monitor thereto.
34. The pump assembly of claim 27 wherein said pump integrity
monitor is a first pump integrity monitor, the pump assembly
further comprising: a second pump integrity monitor having a second
speed sensor coupled to a second pump for monitoring a speed
thereof during operation thereof, and a second acoustic sensor
coupled to said second pump integrity monitor for sampling acoustic
data at a rate based upon the speed.
35. The pump assembly of claim 34 wherein said first pump integrity
monitor is coupled to said second pump integrity monitor to obtain
data from said second pump.
36. The pump assembly of claim 34 further comprising a central host
for analysis of data from the first pump and the second pump
simultaneously.
37. The pump assembly of claim 36 wherein said central host is a
first central host coupled to a second central host at a remote
location for analysis of data from each of said first central host
and said second central host.
38. The pump assembly of claim 27 wherein said acoustic sensor is
coupled to said pump integrity monitor via a high speed acquisition
board to acquire the acoustic data at a rate of more than about
100,000 samples per second.
39. A multi-pump assembly comprising: a first pump assembly having
a first pump integrity monitor with a speed sensor coupled to a
pump of said first pump assembly for monitoring a speed thereof and
an acoustic sensor for sampling acoustic data at a rate based on
the speed; a second pump assembly having a second pump integrity
monitor with a speed sensor coupled to a pump of said second pump
assembly for monitoring a speed thereof and an acoustic sensor for
sampling acoustic data at a rate based on the speed; and a common
manifold in fluid communication with said first pump assembly and
said second pump assembly.
40. The multi-pump assembly of claim 39 wherein the first pump
integrity monitor is configured to decipher acoustic data of said
first pump assembly and said second pump integrity monitor is
configured to decipher acoustic data of said second pump
assembly.
41. The multi-pump assembly of claim 39 wherein the acoustic sensor
of the first pump integrity monitor is one of an accelerometer
coupled to the pump of the first pump assembly and a pressure
transducer disposed within a fluid line coupling said common
manifold and said first pump assembly.
42. The multi-pump assembly of claim 41 wherein the fluid line is
equipped with a choke disposed therein and positioned between the
pressure transducer and said common manifold for one of attenuating
acoustics from said second pump assembly toward the first pump
integrity monitor and dampening acoustics from said first pump
assembly toward the second pump integrity monitor.
43. The multi-pump assembly of claim 39 wherein the first pump
integrity monitor includes a high speed acquisition board to
acquire the acoustic data from the acoustic sensor of the first
pump integrity monitor at a rate of more than about 100,000 samples
per second.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to and is a Continuation in
Part of U.S. patent application Ser. No. 11/482,846, filed on Jul.
7, 2006, which is incorporated herein by reference.
BACKGROUND
[0002] Embodiments described relate to the monitoring of pumps in
use. In particular, embodiments of oilfield pumps and techniques
for their monitoring with a pump integrity monitor are
described.
BACKGROUND OF THE RELATED ART
[0003] Large oilfield operations generally involve any of a variety
of positive displacement or centrifugal pumps. Such pumps may be
employed in applications for accessing underground hydrocarbon
reservoirs. For example, positive displacement pumps are often
employed in large scale high pressure applications directed at a
borehole leading to a hydrocarbon reservoir. Such applications may
include cementing, coiled tubing, water jet cutting, or hydraulic
fracturing of underground rock.
[0004] A positive displacement pump such as those described above
may be a fairly massive piece of equipment with associated engine,
transmission, crankshaft and other parts, operating at between
about 200 Hp and about 4,000 Hp. A large plunger is driven by the
crankshaft toward and away from a chamber in the pump to
dramatically effect a high or low pressure thereat. This makes it a
good choice for high pressure applications. Indeed, where fluid
pressure exceeding a few thousand pounds per square inch (PSI) is
to be generated, a positive displacement pump is generally
employed. Hydraulic fracturing of underground rock, for example,
often takes place at pressures of 10,000 to 20,000 PSI or more to
direct an abrasive containing fluid through a borehole such as that
noted above to release oil and gas from rock pores for
extraction.
[0005] Whether a positive displacement pump as described above, a
centrifugal pump, or some other form of pump for large scale or
ongoing operations, regular pump monitoring and maintenance may be
sought to help ensure uptime and increase efficiency of operations.
That is, like any other form of industrial equipment a pump is
susceptible to natural wear that could affect uptime or efficiency.
This may be of considerable significance in the case of pumps for
large scale oilfield operations as they may be employed at a
production site on a near round the clock basis. For example, in
the case of hydraulic fracturing applications, a positive
displacement pump may be employed at a production site and intended
to operate for six to twelve hours per day for more than a
week.
[0006] Wear on pump components during operation may present in a
variety of forms. For example, internal valve seals of a pump may
be prone to failure, especially where abrasive fluids are directed
through the pump during an application. Issues with other pump
components may develop during operation such as plunger wear,
loosening engine mounts, deteriorating crankshaft bearings, and
transmission breakdown in such forms as a slipping clutch or broken
gear teeth. Thus, as indicated above, regular pump monitoring and
maintenance of pump health may be an important part of ongoing pump
operations.
[0007] Issues with wearing pump components such as those indicated
above may be accompanied by certain vibrations particular to the
type of wear taking place. Therefore, it is not uncommon to monitor
the health of a pump during operation by taking into account such
acoustic or vibration information. For example, a positive
displacement pump may be evaluated during operation by employing an
acoustic sensor coupled to the pump. The acoustic sensor may be a
conventional sonic transmitter used to detect high-frequency
vibrations particular to a leak or incomplete seal within the
chamber of the positive displacement pump, such a leak being a
common precursor to pump failure. By employing an acoustic sensor
in this manner, the costly and somewhat unreliable alternative of
regularly timed interruption of pump operation for manual seal
inspection and replacement may be avoided. Similar acoustic
monitoring of the health of the pump may be employed for the
detection of other types of potential pump component wearing as
well.
[0008] The above described technique of monitoring the health of
the pump via detection of acoustic information during pump
operation faces several practical challenges in implementation. For
example, pump operations often employ several pumps and associated
equipment simultaneously at a production site. In fact, in a
multi-pump operation several pumps may be in fluid communication
with one another through a common manifold. Therefore, even the
detection of a given unhealthy pump condition may not be indicative
of the particular pump having the unhealthy condition.
[0009] In order to distinguish the source of unhealthy acoustic
data in a multi-pump operation as described above each pump of the
multi-pump operation may be operated at a distinct RPM. That is,
each pump of a multi-pump operation may operate at its own unique
RPM with its own acoustically detectable timing. In this manner,
occurrences of unhealthy acoustic data may be correlated to a
particular pump operating at a given RPM. However, as a practical
matter, operating a host of different pumps at a variety of RPM's
for an operation may be near impossible to implement as indicated
below.
[0010] The vast majority of oilfield pumps are only able to operate
at a limited number of speeds making the above manner of operation
potentially very difficult to achieve depending on the particular
level of total output called for in a given operation. In fact,
even if achievable, the operating of pumps at a variety of RPM's
for an operation leads to uneven stress on the pumps with
significantly greater loads applied to certain pumps. As a result,
there is a greater likelihood of pump failure during the operation.
Furthermore, regardless of the RPM assigned to a particular pump of
a multi-pump operation, natural inconsistencies in behavior of pump
components may require data collection over a period of operating
time before any reliable acoustic analysis may take place. This
delays diagnosis of unhealthy conditions and increases
computational complexity of such monitoring, thus requiring
significant processing capacity to carry out. Thus, addressing pump
health over the long haul remains primarily addressed through
regular manual intervention or acoustic monitoring techniques of
limited diagnostic effectiveness.
SUMMARY
[0011] An embodiment of monitoring a pump assembly is disclosed
wherein the pump assembly is operated and timing information
relative thereto is recorded. Sampling of acoustic data then occurs
with a high speed acquisition mechanism followed by an evaluation
of the acoustic data in light of the timing information. Sampling
of acoustic data may also take place based on a speed of the
operating pump assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a side partially sectional view of a pump assembly
employing an embodiment of a pump integrity monitor.
[0013] FIG. 2 is a cross-sectional view of a portion of the pump
assembly of FIG. 1.
[0014] FIG. 3 is a perspective partially sectional view of an
embodiment of employing the pump assembly of FIG. 1 in a multi-pump
operation.
[0015] FIG. 4 is a chart depicting data obtained by employing an
embodiment of the pump integrity monitor and pump assembly of FIG.
1.
[0016] FIG. 5A is a graph depicting data obtained from employing an
embodiment of the pump integrity monitor and pump assembly of FIG.
1.
[0017] FIG. 5B is a graph depicting data obtained from employing
another embodiment of the pump integrity monitor and the pump
assembly of FIG. 1.
[0018] FIG. 6 is a flow-chart summarizing an embodiment of
employing the pump integrity monitor and pump assembly of FIG.
1.
DETAILED DESCRIPTION
[0019] Embodiments are described with reference to certain positive
displacement pump assemblies for fracturing operations. However,
other types of pumps may be employed for a variety of operations.
Regardless, embodiments described herein include a pump assembly
100 that incorporates a pump integrity monitor 101 having
particular capabilities. For example, the pump integrity monitor
101 may employ particularly located sensors in conjunction with a
high speed data acquisition board that takes up acoustic data from
the pump assembly 100 a rate algorithmically adjusted to minimize
the effect of noise from neighboring equipment, including noise
from equipment and pumps that are in fluid coupling with the pump
assembly 100. Furthermore, the pump integrity monitor 101 may
acquire data at a lower non-uniform sampling rate based on
operating speed of equipment of the pump assembly 100, thereby
drastically increasing processing capacity. In a particular
example, the pump integrity monitor 101 may acquire acoustic data
based on the speed of a pump 150 and thus, plot data in line with
positioning characteristics of the pump 150 with less computational
complexity.
[0020] Referring specifically now to FIG. 1, an embodiment of a
pump assembly 100 is shown equipped with a pump integrity monitor
101. In the embodiment shown, the pump assembly 100 includes a pump
150. The pump 150 shown is a positive displacement pump that may be
of a triplex configuration and for use in a fracturing operation.
However, other types of pumps, including centrifugal pumps, may be
employed for a variety of applications according to embodiments
described herein.
[0021] The above-described pump assembly 100 includes a variety of
equipment with a multitude of parts susceptible to natural wearing
and deterioration during operation. In the embodiment shown, this
equipment includes a pump 150 with a fluid housing 157 in which a
fluid is pressurized for distribution to a fluid pipe 165 and
ultimately to a common fluid line 175 as described further herein.
The pressurization of the fluid within the fluid housing 157 is
created by plungers as directed by a rotating crankshaft 155 of the
pump 150. With the fracturing pump 150 of the embodiment shown,
pressurization of up to about 20,000 PSI may be achieved in this
manner. Alternatively, other degrees of pressurization may be
achieved for other applications. For example, where the pump 150 is
to be employed in a cementing application, up to about 5,000 PSI
may be generated as indicated. Additionally, embodiments of the
pump 150 may be employed for coiled tubing or water jet cutting
applications.
[0022] The crankshaft 155 is driven by a driveline mechanism 180,
itself, driven by an engine 125 as directed through a transmission
140. The engine 125 may be a 200 Hp to 5,000 Hp prime mover. In the
embodiment shown, all of this equipment is accommodated at the same
platform 130 for placement and use at a production site, such as
the well fracturing site 300 shown in FIG. 3. The platform 130 may
be a skid for dropping in tact at the production site, part of a
conventional trailer, or other form of delivery mechanism.
[0023] With added reference to FIG. 2, all of the above described
equipment and components thereof, are subject to natural wear
during operation as indicated. Therefore, the pump integrity
monitor 101 is provided at the platform 130. In the embodiment
shown, the pump integrity monitor 101 may include several circuit
boards within a control box for sampling and analyzing a host of
acoustic and other information. The pump integrity monitor 101 may
also include a variety of sensors 120, 110, 179, 225 for obtaining
such information during operation of the pump assembly 100 (see
also FIG. 2). In particular, as shown in FIG. 1, the information
may relate to harmonics of the pump assembly 100 in operation as
detected by an acoustic sensor 110 or a pressure transducer 179.
Additionally, as detailed further below, operational timing
information such as the position of a driveline or crankshaft may
be detected by a proximity switch 120 or an index sensor 225,
respectively.
[0024] Similar to the embodiment described above, an index sensor
may be coupled to a flywheel housing to obtain engine timing
information. The engine timing sensor may be employ a magnetic
pickup that senses position of a location on a rotating part
coupled to the engine 125 such as its flywheel. In this sense, the
information is obtained similar to information obtained by the
index sensor 225 as described further below. This information may
be analyzed by the pump integrity monitor 101 in conjunction with
acoustic data obtained from an acoustic sensor coupled to the
engine 125 or transmission 140 for establishing a condition thereof
as described below. In an embodiment where the pump 150 is
electrically driven, the sensors described here may be modified and
located to acquire data regarding electrical current input.
[0025] Continuing with reference to FIG. 1, a circuit board of the
pump integrity monitor 101 may be provided in the form of a high
speed acquisition board which may include no microcontroller or
processing capacity. Rather, the high speed acquisition board may
be dedicated to sampling acoustic, vibration, or pressure sensor
data at a rate of between about 100 to about 600,000 samples per
second or more. The high speed acquisition board may be dedicated
to obtaining data from the acoustic sensor 110 and/or the pressure
transducer 179 as indicated above. These sensors 110, 179 may be
specifically positioned to acquire acoustic vibration data from the
pump assembly 100 during its operation. In an embodiment where the
pump 150 is hydraulic in nature, such sensors 110, 179 may be
positioned and equipped to acquire hydraulic pressure data in place
of acoustic data as described herein. Regardless, the acquired data
may be analyzed by the pump integrity monitor 101 in order to
provide a recognizable pattern of pump health or integrity
information so as to alert an operator of an unhealthy condition of
the pump assembly 100 should one arise. Furthermore, it is not
required that the pump flow rate remain constant in order to employ
techniques described further below.
[0026] Continuing with reference to FIGS. 1 and 2, an example of an
acoustically detectable unhealthy condition in the pump assembly
100 is described in detail. That is, while a host of harmonic or
vibration data is provided by an operating pump assembly 100,
certain data may be indicative of a variety of unhealthy
conditions. Acoustic profiles of common unhealthy conditions may be
pre-loaded on a processor of the pump integrity monitor 101 to
allow analysis. With respect to the embodiments described herein,
these unhealthy conditions may include plunger wear, loosening
engine mounts, piston issues, deteriorating crankshaft bearings,
and transmission breakdown in such forms as a slipping clutch or
broken gear teeth to name a few. Another such example includes the
unhealthy condition of a failing pump valve seal 260 as shown in
FIG. 2. This type of failure may be prone to occur in circumstances
where abrasive fluids are directed through a pump 150 such as
during a fracturing application.
[0027] With particular reference to FIG. 2, the pump 150 includes a
plunger 290 for reciprocating within a plunger housing 207 toward
and away from a chamber 235. In this manner, the plunger 290
effects high and low pressures on the chamber 235. For example, as
the plunger 290 is thrust toward the chamber 235, the pressure
within the chamber 235 is increased. At some point, the pressure
increase will be enough to effect an opening of a discharge valve
250 to allow the release of fluid and pressure within the chamber
235. The amount of pressure required to open the discharge valve
250 as described may be determined by a discharge mechanism 270
such as valve spring which keeps the discharge valve 250 in a
closed position until the requisite pressure is achieved in the
chamber 235. In an embodiment where the pump 150 is to be employed
in a fracturing operation pressures may be achieved in the manner
described pressures of up to about 20,000 PSI may be achieved in
the manner described here.
[0028] The plunger 290 may also effect a low pressure on the
chamber 235. That is, as the plunger 290 retreats away from its
advanced discharge position near the chamber 235, the pressure
therein will decrease. As the pressure within the chamber 235
decreases, the discharge valve 250 will close returning the chamber
235 to a sealed state. As the plunger 290 continues to move away
from the chamber 235 the pressure therein will continue to drop,
and eventually a low or negative pressure will be achieved within
the chamber 235. Similar to the action of the discharge valve 250
described above, the pressure decrease will eventually be enough to
effect an opening of an intake valve 255. The opening of the intake
valve 255 allows the uptake of fluid into the chamber 235 from a
fluid channel 245 adjacent thereto. The amount of pressure required
to open the intake valve 255 as described may be determined by an
intake mechanism 275 such as spring which keeps the intake valve
255 in a closed position until the requisite low pressure is
achieved in the chamber 235.
[0029] As described above, and with added reference to FIG. 1, a
reciprocating or cycling motion of the plunger 290 toward and away
from the chamber 235 within the pump 150 controls pressure therein.
The valves 250, 255 respond accordingly in order to dispense fluid
from the chamber 235 through a dispensing channel 240 and
ultimately to a fluid pipe 165 at high pressure. That fluid is then
replaced with fluid from within a fluid channel 245. All of the
movements of the various parts of the pump 150 as described may
resonate to a degree throughout the pump 150 including to its
non-moving portions, such as at the fluid housing 157 within which
the chamber 235 is located. Thus, as indicated above, an acoustic
sensor 110 may be secured thereto for sensing such resonating
vibrations.
[0030] As noted, certain vibrations detected by the acoustic sensor
110 of FIG. 1 may be indicative of an unhealthy valve seal 260 of
the pump 150. For example, upon closer inspection of FIG. 2 it is
apparent that the discharge valve 250 includes a conformable valve
seal 260 for sealing off of the chamber 235. The conformable nature
of such a valve seal 260 is conducive to the pumping of abrasive
containing fluids through the pump 150 as is often called for in
the case of fracturing operations. For example, the abrasive fluid
may include a proppant such as sand, ceramic material or bauxite
mixed therein. The conformable nature of the valve seal 260 allows
it to conform about any proppant present at the interface 275 of
the discharge valve 250 and seat 280. Unfortunately, the
conformable nature of the valve seal 260 also leaves it susceptible
to the unhealthy circumstance of degradation by such abrasive
fluids.
[0031] A conformable valve insert 260 of urethane or other
conventional polymers employed in a conventional fracturing
operation as described above may degrade completely in about one to
six weeks of substantially continuous use. As this degradation
begins to occur a completed seal fails to form between the valve
250 and the valve seat 280. Thus, as noted above, an acoustic
vibration indicative of an unhealthy condition of the operating
pump 150 may then persist that is attributable to a growing leak
between the chamber 235 and the dispensing channel 240.
[0032] Continuing now with reference to FIGS. 1-3, the above
described unhealthy condition of a failing pump valve seal 260 may
be acoustically detectable by the acoustic sensor 110 as indicated.
However, as shown in FIG. 3, the pump 150 may be part of but one
pump assembly 100 of a multi-pump assembly 300 at a production site
375. Therefore, embodiments described herein include techniques for
discerning acoustic data emanating from other assemblies 302, 303,
304, 305, 306 and equipment from the acoustic data of the pump
assembly 100 such as that indicative of the unhealthy condition of
the valve seal 260 as indicated.
[0033] As shown in FIG. 3, and indicated above, multiple pump
assemblies 302, 303, 304, 305, 306 are provided at the production
site 375 in addition to the pump assembly 100 of FIG. 1. Each of
the assemblies 302, 303, 304, 305, 306, and 100 may be no more than
10-12 feet from one another, with each operating at 1,500 Hp to
5,000 Hp to propel an abrasive fluid 310 into a well 325. The
abrasive fluid 310 may be directed into the well 325 and directed
to fracturable rock 315 or other earth material as is the nature of
a convention fracturing operation.
[0034] Apart from the acoustics emanating from the pump assembly
100 of FIG. 1, a considerable amount of noise is generated in the
above described fracturing operation of FIG. 3. In fact, in
continuing with reference to FIG. 3, added equipment such as a
blender 307 may be provided on site adding noise to the operation.
Furthermore, each assembly 302, 303, 304, 305, 306, and 100 may
generate up to about 20,000 PSI for directing the abrasive fluid
310 through a common manifold 375 and to a well head 350 coupled to
the well 325. That is, all of the assemblies 100, 302, 303, 304,
305, 306 may be in fluid communication with one another. As a
result of such communication, the ability of acoustics emanating
from a single pump assembly to resonate at an adjacent pump
assembly is enhanced. Thus, referring back to FIG. 1, the ability
of the pump integrity monitor 101 to decipher the source of
acoustics for establishing the condition of its associated pump
assembly 100 in particular, may be of significant benefit.
[0035] Continuing with reference to FIGS. 1-3, in spite of the
above described fluid communication among pump assemblies 100, 302,
303, 304, 305, 306 during conventional operations such as
fracturing, the pump integrity monitor 101 is configured for use in
a manner that allows deciphering and favoring the acquisition of
acoustic information relative to its own particular pump assembly
100. This may be achieved by the pump integrity monitor 101
employing both the above noted high speed acquisition board in
combination with one or both of two sensors 110, 179 positioned to
enhance the sensing of acoustic information from the pump assembly
100 of FIG. 1 in particular. That is, as indicated, the high speed
acquisition board may be dedicated to sampling sensor data at a
rate of between about 100 to about 300,000 samples per second or
more. Thus, as detailed further below, the acquisition of acoustic
data from the pump assembly 100 of FIG. 1 may be enhanced by use of
the sensors 110, 179 positioned as indicated above whereas the
resolution of this acoustic data may be enhanced by use of such a
high speed acquisition board.
[0036] Continuing with reference to FIGS. 1-3, the pump integrity
monitor 101 may be directly wired to one or both of two sensors
110, 179 positioned to enhance the sensing of acoustic information
from the pump assembly 100 of FIG. 1 in particular. For example,
the first sensor, the above described acoustic sensor 110, is
positioned directly on the fluid housing 157 of the pump 150. The
second sensor, the above noted pressure transducer 179, may be
positioned within the common fluid line 175 to the manifold 375.
While positioned in a common fluid area, the pressure transducer
179 is located to the pump side of choke 177 that briefly cuts down
the inner diameter of the line 175 (e.g. about in half). This
contributes to the attenuation of acoustics emanating from outside
of the pump assembly 100 of FIG. 1. Thus, the sensing of acoustic
information from the pump assembly 100 of FIG. 1 by the pressure
transducer 179 is still enhanced. In fact, the location of the
choke 177 also aids in dampening of acoustics from the pump
assembly 100 of FIG. 1 to other assemblies 302, 303, 304, 305, 306
such as those of FIG. 3.
[0037] In addition to the enhanced acquisition of acoustic data
from the pump assembly 100 of interest, the enhanced resolution of
data as indicated renders noise from other sources of little
significance. A speed sensor such as a proximity switch 120 may be
provided to the pump integrity monitor 101 and coupled to a
rotating driveline mechanism 180 for monitoring speed of the
operating assembly 100, thus, allowing the processor to confirm
outside noise as out of sync from the assembly 100. Therefore, with
added reference to FIG. 3, such a high rate of acoustic sampling by
the pump integrity monitor 101, the need to operate separate
assemblies 100, 302, 303, 304, 305, 306 of a multi-pump operation
at significantly different and/or constant speeds is substantially
obviated. Rather, distinction between noise emanating from outside
sources, out of time from the associated assembly, may readily be
deciphered by a processor of the pump integrity monitor 101 with
such a vast amount of acoustic data at its disposal.
[0038] As described above, the pump integrity monitor 101 may be
employed to diagnose an unhealthy condition such as a leaking pump
valve seal 260 in spite of surrounding noise at a production site
375. Furthermore, all other assemblies 302, 303, 304, 305, 306 of a
multi-pump operation such as that shown in FIG. 3 may be equipped
with individual pump integrity monitors for diagnosis of unhealthy
conditions of the associated pump assembly 302, 303, 304, 305, 306.
Again, such unhealthy conditions may include leaking pump seals,
plunger wear, valve spring wear, loosening engine mounts, pump
mounts, piston issues, deteriorating crankshaft bearings,
crossheads, pony rods, transmission breakdowns such as clutch
slippage or broken gear teeth and any other conditions presenting
acoustic abnormalities.
[0039] While the above described techniques of employing the pump
integrity monitor 101 provide detection of the health of a given
assembly 100 regardless of surrounding noise, acoustic data
indicative of equipment health or integrity may also be employed in
a manner drastically reducing the amount of processor capacity
required for establishing equipment health. That is, rather than
sampling the above noted acoustic data at a constant rate (i.e.
equidistant sampling) and performing an FFT to plot the
information, acoustic data may be sampled at a rate based on the
speed of the operating equipment (i.e. non-uniform or angular
sampling). In this manner the need for a discrete FFT conversion
may be eliminated or transferred to the angular domain, also
referred to herein as the "order" space. The pump integrity monitor
101 may be provided with the capability to detect and analyze much
higher frequencies. For example, frequencies substantially beyond
25 KHz, more preferably beyond 100 KHz may be analyzed by a
processor of the pump integrity monitor 101. As a result, leaks or
other acoustically detectable problems encountered by the pump
assembly 100 may be detected much earlier on, when presenting at
such higher frequencies. In fact, in an alternate embodiment, a
very limited Fourier analysis may be performed over a small
frequency range in order to increase spectral resolution.
Nevertheless, the signal detection may be obtained earlier on at
higher frequencies.
[0040] For example, with reference to FIGS. 1-3 above, the pump
integrity monitor 101 may sample acoustic data at a rate of between
about 50 and 5,000 samples per revolution of the crankshaft 155.
Thus, positioning information relative to cycling of the pump 150
may automatically be provided without any need to perform FFT
conversions. In order to regulate the sampling of acoustic data in
this manner, a sensor may be provided to monitor or track the
timing of a moving part of the pump 150 and thus, its speed. For
example, as shown in FIG. 2, an index sensor 225 is provided
adjacent a plunger 290 that is driven by the noted crankshaft 155
of FIG. 1. The plunger is equipped with a collar 227 detectable by
the index sensor 225 such that timing information may be
transmitted to the pump integrity monitor 101. In this manner, the
processor of the pump integrity monitor 101 need only keep time of
the operating pump 150 in acquiring and plotting acoustically
obtained data relative thereto.
[0041] Referring now to FIG. 4, with added reference to FIGS. 1-3,
acoustic data acquired by the pump integrity monitor 101 via
techniques described above is plotted on a chart. The chart shown
plots acoustic data that has been obtained from a pump assembly 100
having a pump 150 with a leaking valve seal 260 as shown in FIG. 2.
In the embodiment shown, between about 500 and about 5,000 samples
of acoustic data have been obtained for a given revolution of the
crankshaft 155 of the pump 150. Thus, given timing information from
the index sensor 225 acoustic data has been plotted without the
requirement of FFT conversions, thereby saving substantial
processor capacity of the pump integrity monitor 101.
[0042] Continuing with reference to FIG. 4, timing information from
the index sensor 225 allows for the plotting of an acoustic profile
of the angular position of the cycling pump 150 based on three
plunger reciprocation areas 1, 2, 3. That is, in the embodiments
described herein, the pump 150 is of a positive displacement
triplex configuration. Thus, three separate plungers, such as the
plunger 190 of FIG. 2, reciprocate in any given cycle of the pump
150. A variety of acoustic data 400, 401, 402, 403, 475 may be
plotted in accordance therewith.
[0043] The chart of FIG. 4 reveals that certain acoustic data is
persistent throughout an entire cycling of the pump 150. This
persistent acoustic data 475 may be the expected acoustics of the
operating pump 150 and other equipment of the assembly 100. Due to
the improved resolution and enhanced detection provided by the pump
integrity monitor 101 as detailed above, the probability of an
overwhelming amount of persistent acoustic data 475 emanating from
another assembly (i.e. 302, 303, 304, 305, 306 of FIG. 3), is
minimized. Regardless, such data fails to be indicative of an
unhealthy condition of the pump 150 associated with the pump
integrity monitor 101 being employed.
[0044] The chart of FIG. 4 is depicted in a logarithmic scale as
alluded to above, with a maximum frequency detectable at half the
sampling frequency (i.e. Fs/2). With respect to particular plunger
reciprocation areas 1, 2, 3 of the chart, each includes strike data
401, 402, 403, revealing two valve strikes per plunger
reciprocation, resonating at between about 1/64 and about 3/8 of
the sampling frequency (Fs). This would be expected as described in
detail above with respect to FIG. 2 where valves 250, 255 strike
valve seats 280, 285 as described above. Again, this particular
acoustic data fails to be indicative of any unhealthy condition of
the pump assembly 100.
[0045] Unfortunately, upon close examination of the first plunger
reciprocation area 1 an unhealthy condition of the pump assembly
100 is revealed. That is, recalling the leaking valve seal 260 of
FIG. 2, unhealthy acoustic data indicative of this leak presents in
the form of leak data 400 in the first plunger reciprocation area
1. The leak data 400 presents immediately after the striking of a
valve (i.e. 250) as shown by the strike data 401. As described with
reference to FIG. 2, it is at this time that a completed seal fails
to form between the valve 250 and the valve seat 280. Thus, an
acoustic vibration, depicted here as leak data 400, resonates as
fluid leaks between the chamber 235 and the dispensing channel 240.
An unhealthy condition of the pump assembly 100 is thereby detected
and displayed.
[0046] In FIG. 4 detailed above, leak data 400 is depicted in a
chart that reflects the angular position of a cycling pump 150 such
as that of FIG. 1. The depiction of acoustic leak data 400 in this
manner provides some insight into the condition of pump parts
driven by a rotating mechanism such as the crankshaft 155. However,
with reference to FIG. 1, a variety of other equipment such as an
engine 125, transmission 140 or driveline mechanism 180 may also be
subject to wear and breakdown. Similarly, the health of such
equipment may be detected and monitored according to techniques
described above. That is, the above-described techniques may be
employed for analyzing both pump and engine data. For example,
acoustic data corresponding to a gear ratio employed by the
transmission 140 may be indicative of a problem prior to the
driveline mechanism 180. Similarly, as described below, unexpected
acoustic data corresponding to the rpm of the engine 125 may be
indicative of engine side issues such as with engine mounts or
piston reciprocation. Additionally, it may be of benefit to examine
the acoustics of such equipment in terms other than angular
positioning. For example, the amplitude or power (or power spectral
density), as shown in FIG. 5A, may provide insight into the
condition of operating equipment in other frequency ranges as
detailed further below.
[0047] Referring now to FIG. 5A, with added reference to FIG. 1, a
graph is shown depicting an acoustic profile of acoustic data
acquired from a pump assembly 100 having a four stroke 12 cylinder
engine 125 that is running at about 2,400 rpm's. This may be the
same pump assembly 100 as that depicting the acoustic data of FIG.
4. However, by way of comparison, the acoustic data of FIG. 4
presents at frequencies higher than the chart of FIG. 5A extends.
However, an extension of FIG. 5A in terms of frequency would reveal
the acoustic pump related data depicted in FIG. 4. Another
distinction from FIG. 4 is that in FIG. 5A, rather than depicting
the acoustic frequency data against angular positioning, the graph
of FIG. 5A depicts acoustic data against power as described further
below.
[0048] With added reference to FIG. 1, FIG. 5A depicts acoustic
data relative to an engine 125 operating at about 2,400 rpm as
indicated. Such an engine 125 would generate a frequency of about
40 Hz by definition. Thus, an examination of the chart of FIG. 5A
at about 40 Hz reveals acoustic engine rpm data 560. In fact, the
greatest amount of power revealed for the frequency range depicted
in FIG. 5A is revealed in the form of the acoustic engine rpm data
560. Other acoustic data is revealed such as camshaft data 551 at
about 20 Hz and piston data 580 at about 240 Hz. Again, given a
conventional 12 cylinder engine 125 running at about 2,400 rpm, the
location of camshaft data 551 at half that of the engine rpm data
560 and the location of the piston data 580 is to be expected.
However, abnormalities in such data may be telling. For example, an
abnormality in the camshaft data 551 may be indicative of misfiring
whereas an abnormality in rpm data 560 may be indicative of engine
imbalance, misalignment, abnormal torque reaction, or a weak
foundation of the engine 125.
[0049] While the location of the acoustic data 551, 560, 580
reflects the expected operating acoustics of a 12 cylinder engine
125 operating at 2,400 rpm, additional acoustic information is
presented in the graph of FIG. 5A. Namely, engine rpm data 560
presents with a peak 565 that breaks into a smooth portion 562 and
a smaller rough portion 567 by comparison. Similarly, the piston
data 580 includes a smooth portion 582 and a rough portion 587.
Thus, it is apparent that a problem has arisen in the firing or
operating of at least one of the pistons of the engine. That is,
rather than acoustic leak data 400 apparent in FIG. 4, rough
portions 567, 587 of data present in FIG. 5A revealing an unhealthy
condition in the pump assembly 100 outside of the pump 150.
Fortunately, however, with particular reference to the z-axis of
the chart of FIG. 5A, it does not appear that the problem is
increasing over the period of time shown. Therefore, an operator
may have time to intervene before failure of the operating pump
assembly 100 due to the problem shown.
[0050] In addition to the acoustic data depicted in FIG. 5A 551,
560, 580, additional data relative to the condition of the engine
125 may be obtained. For example, in such an engine 125 as
described above, cylinder combustion peaks at about 60 Hz, 100 Hz,
140 Hz, and 180 Hz might be expected along with peaks representing
harmonics of crankshaft speed at about 80 Hz, 120 Hz, 160 Hz, and
200 Hz. Such acoustic data may again be analyzed to determine a
condition of the engine 125. For example, a peak representing
crankshaft harmonics at about 80 Hz that is significantly higher
than other crankshaft harmonic peaks may be indicative of a problem
such as vibration damper failure relative to a position of the
rotating crankshaft.
[0051] Referring now to FIG. 5B, again with added reference to FIG.
1, a graph is shown similar to that of 5A, but with reference now
to pump acoustics (i.e. as opposed to engine acoustics). For the
embodiment shown and described below, the pump 150 is a positive
displacement pump 150 of a triplex configuration. The pump 150
includes a crankshaft 155 rotating at a frequency of about 4 Hz
where an initial peak is depicted. In a circumstance of an
unhealthy pump condition correlating to the timing of the
crankshaft rotation, the peak depicted at about 4 Hz may rise or
present otherwise abnormally. Such pump failures may include a
valve leak, broken valve spring, loose plunger, loose pump mount,
or crank bearing failure.
[0052] Given that the pump 150 employs three plungers 290 as
indicated above, each reciprocating with every rotation of the
crankshaft 155, the peak at about 12 Hz is to be expected.
Furthermore, a peak is noted at about 24 Hz which reflects a
reduction ration of about six that is provided by gearing between
the transmission 140 and the crankshaft 155. For the embodiment
shown, a high peak at about 24 Hz would be indicative of problems
such as with the transmission 140, driveline 180, or related parts.
Similarly, where a bull gear of the described gearing is equipped
with say 108 teeth, a harmonic peak at about 432 Hz would be
expected as shown. Abnormalities in this peak would be indicative
of degradation or other problems with gearing teeth for the
depicted embodiment.
[0053] Referring now to FIG. 6, an embodiment of employing a pump
integrity monitor is summarized in the form of a flow chart. The
monitor is employed as a part of a pump assembly that is in
operation as indicated at 620. As noted above, the pump assembly
may be operated in conjunction with a host of other equipment,
including other pump assemblies in fluid communication therewith.
Nevertheless, as indicated, the pump integrity monitor may be
employed to decipher the health or integrity that is particular to
the pump assembly.
[0054] Deciphering the health of the pump assembly may be achieved
in part by employing the pump integrity monitor to record timing
information of the pump assembly as indicated at 635 (e.g. perhaps
with a proximity switch). With timing information in mind, a vast
amount of acoustic data may be sampled with a high speed
acquisition mechanism, perhaps at between about 100,000 and 300,000
samples per second as indicated at 650. With properly located
sensors to obtain such samples, a fairly high resolution of the
acoustics of the operating assembly may be obtained for evaluation
as indicated at 680. Additionally, the acoustic data may be sampled
based on the speed of the pump as noted at 660 such that an FFT
conversion of such data may be entirely avoided saving significant
processing capacity of the pump integrity monitor.
[0055] Embodiments described herein include a method of monitoring
pump integrity with a pump integrity monitor in a manner that
distinguishes outside noise from acoustics related to the pump. In
fact, even where surrounding noise emanates from other pumps
fluidly coupled to the pump of interest, the pump integrity monitor
is operated so as to distinguish outside noise without requiring
that other pumps be operated at substantially different speeds or
constant rates of speed. Thus, there is no need to place undue
loads on certain pumps of a multi-pump operation in order to
acoustically monitor the operating health of each pump.
Furthermore, the pump integrity monitor is operated in such a
manner so as to dramatically increase processing capacity by
elimination of FFT conversion requirements and to shorten time for
diagnosis of the health of the pump. Thus, the practical
effectiveness of acoustic diagnostics of an operating pump assembly
may be significantly improved.
[0056] Although exemplary embodiments describe particular
techniques for monitoring pump assemblies such as positive
displacement pumps for fracturing applications, additional
embodiments are possible. For example, several pump integrity
monitors may be coupled to a central host or one another over a
network for analysis of operational conditions at a variety of
pumps or even multiple operation sites. Additionally, analysis
techniques described above may be further and more particularly
tailored based on program configuration. In one example, spectrum
averaging bound to timing positions (i.e. stacking) may be employed
to reduce noise and improve resolution irrespective of steady or
repeatable conditions. Cepstral analysis may also be employed for
multiple harmonics originating from a variety of mechanical parts.
Joint time-frequency analysis may even be employed to handle
time-varying frequency content through patter recognition in two
dimensional time-frequency space wherein a Bayesian-based pattern
classification technique is employed with an embedded database of
vibration signatures.
[0057] In addition to that above, methods may be employed tailored
to the pump integrity monitor electronics employed. In this regard,
interleaved virtual sub-devices may be integrated into a single
firmware frame, re-programmable virtual devices may be employed
with functionality based on a particular frequency range of
interest while still within a single frame, and portable device
implementation may be employed.
[0058] Further additional features may be provided for employing
the pump integrity monitor described herein such as pre-programming
of the pump integrity monitor with a variety of vibration
signatures to enhance pattern recognition for the types of problems
likely to be acoustically detected during pump operation. In fact,
to enhance such recognition, applications may be run that tend to
avoid natural operating frequencies that may overlap with
frequencies otherwise reflective of an unhealthy pump condition.
Furthermore, many other changes, modifications, and substitutions
may be made without departing from the scope of the described
embodiments.
* * * * *