Note: Descriptions are shown in the official language in which they were submitted.
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Title: METHOD, SYSTEM, AND DEVICE FOR DISPLAYING OPERATING
PARAMETERS OF RECIPROCATING OIL WELL PUMPING
APPARATUS
FIELD OF THE INVENTION
The present invention relates generally to reciprocating oil well pumping
apparatus which has a rod that is moveable between a top-of-stroke position
(TOSP) and a bottom-of-stroke position (BOSP). More particularly, the
present invention relates to methods, systems and devices for displaying
operating parameters of reciprocating oil well pumping apparatus.
BACKGROUND OF THE INVENTION
There are many different methods for producing oil from an oil well. Some
wells, known as "free flowing" oil wells require no pumping as the oil flows
freely from the ground to the surface. Most oil wells, however, are not free-
flowing and require a method to lift the oil from the well to bring it to the
surface. These methods are broadly included in a wide spectrum of
methods called "artificial lift". Artificial lift is needed in cases when oil
wells
are not free-flowing, or are free-flowing at an insufficient rate. Many
different
types of artificial lift pumping systems are known and employed throughout
the world. Typical artificial lift pumping systems are reciprocating rod-lift
pumping apparatus, the most common examples of which are horse head
or walking beam pumps and hydraulic pumps.
One example of a typical known horse head pump arrangement is described
in U.S. Pat. No. 4,651,578 to Thomson. Such horse head pumps include a
walking beam pivotally mounted on a Samson post which serves as a
fulcrum about which the walking beam oscillates. One end of the walking
beam carries the horse head, and the other end is connected to the
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oscillation drive means which includes a pitman and counter-weight crank
arm drive unit. The horse head is pivotally attached to the one end of the
walking beam and is fitted with a cableguide on which cable is mounted for
connecting the horse head to a sucker rod string extending downwardly to
the subsurface pump located in the well.
One example of a known hydraulic oil well pump is described in U.S. Pat.
No. 7,762,321 to Fesi et al. This hydraulic oil well pump employs a
compensating type hydraulic pump, a directional valving arrangement and
a proportioning valving arrangement. When the directional valve is
energized, oil is directed to the rod end of the hydraulic cylinder. The rod
or
piston part of the hydraulic cylinder will then elevate until a first limit
switch
is actuated which then will de-energize the directional valve and send a
current signal to the proportional valve. The current signal to the
proportional valve forces it to open to a point at which the cylinder rod
would
extend at the desired velocity until it reaches a second limit switch. The
second limit switch is near the bottom of travel of the rod or piston. The
current signal to the proportional valve is then decreased, creating a choking
arrangement that forces the cylinder rod to decelerate. The cylinder rod
then reaches another limit switch. Upon reaching the third limit switch, the
signal is removed from the proportional valve so that it closes. This halts a
draining of fluid from the hydraulic cylinder. At the same time, a voltage
signal is sent to the directional valve opening it so that pump flow again
travels from the pump to the hydraulic cylinder and once again elevates the
rod and the connected pumping string or sucker rod.
The up and down movements of the sucker rod (i.e. upstroke and
downstroke) in a typical oil well pump is governed by either a simple
mechanical translation of a rotational motion of an electric motor as in the
case of horse head pumps, or a rudimentary controller which simply
energizes and de-energizes the directional valve in direct response to
activity of limit sensors as in the case of hydraulic pumps.
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When an oil well pump is installed in the field it is set up and calibrated to
operate with a specific strokes per minute. Over time, the SPM value may
change due to changes in the oil well, changes in the oil well pump, or any
of a number of other factors. A decrease in SPM can equate to significant
yearly production losses. An increase in SPM can also be problematic as
it can result in inefficient pumping and increased wear and tear on the
equipment.
Accordingly, changes in SPM of oil well pumps are typically monitored by
operators using their eyes to count upstrokes and downstrokes and relating
that information to a time obtained with a stop watch. The problem with this
method of monitoring pumping apparatus parameters is that it results in
readings which are inconsistent and imprecise. More problematic is that
slight deviations in the stroke speeds or strokes per minute, intermittent
deviations, or deviations occurring between scheduled readings go
unnoticed.
One attempt at monitoring the SPM of a hydraulic oil well pump is disclosed
in U.S. Pat. No. 4,076,458 (Jones). Jones discloses an automatic pump
speed controller for controlling and maintaining the strokes per minute of a
down-hole oil well pump and providing signals on the surface indicating the
actual strokes per minute of the pump. The Jones controller calculates the
SPM of the pump with use of a transducer which changes the shock waves
from changes in the pressure accompanying each stroke of the pistons of
the hydraulic pump into electrical signals. As such the Jones controller is
integral to the oil well pump itself and is not intended as a stand alone
device for use in conjunction with for example a conventional pump
controller governed reciprocating hydraulic oil well pump, or a conventional
horse head oil well pump driven with a motor as opposed to hydraulics.
U.S. Pat. No. 5,184,507 issued to Drake discloses measuring and using
surface hydraulic fluid pressure and sucker rod displacement to analyze the
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performance of a pumped oil well having a surface hydraulic actuator
connected to a downhole pump by the sucker rod. The pressurized
hydraulic fluid actuates a cyclic motion of the rod and a pumping of the oil.
The measured rod motion and hydraulic fluid pressure are used together
with an added flexible rod simulator to calculate a performance
characteristic, namely hydraulic pressure vs. displacement, which is said to
account for rod interactions with the hydraulic actuator and hydraulic pump.
Drake requires tapping into the oil well pump's hydraulics and adding a rod
displacement transducer. However, the performance characteristic
measured by Drake is not easily understandable and requires careful
interpretation and analysis by the operator.
U.S. Pat. No. 5,406,482 issued to McCoy discloses mounting an
accelerometer on a horse head oil well pump to move in conjunction with the
sucker rod. An output signal from the accelerometer is digitized and
provided to a portable computer. The computer processes the digitized
accelerometer signal to integrate it to first produce a velocity data set and
second produce a position data set. The computer then processes the
accelerometer data sets and calculates strokes per minute and velocity
parameters of the rod, and displays the information in the form of plots. As
in the above Drake reference the information displayed by computer is not
easily understandable and requires interpretation and analysis by the
operator.
Other prior art patent documents of general interest in the field include U.S.
Pat. Nos. 3,343,409 (Gibbs), 4,213,740 (Chien), 4,503,752 (Olson),
4,680,930 (Dollison), 5,044,888 (Hester), 5,159,832 (White), 5,184,507
(Drake), 5,406,482 (McCoy), 5,800,063 (Stanley), U.S. Pat. App. Pub. No.
2011/0103974 (Lamascus), and CA Pat. Nos. 2,414,646 (Watson), and
2,526,345 (Palka).
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SUMMARY OF THE INVENTION
In view of the foregoing, there is a need for a simple device for monitoring,
and displaying operating parameters of an oil well pump to an operator in a
straightforward and easily understandable manner and to alert the operator
to changes in the operating parameters which may warrant further
investigation. Preferably, the device is inexpensive to manufacture and
install, and overcomes at least some of the problems associated with prior
art.
The present invention is directed to a monitor device to display operating
parameters of a reciprocating oil well pumping apparatus to an operator in
a straightforward and easily understandable manner. Preferably the monitor
device has display means which displays at least the following operating
parameters to the operator: a strokes per minute (SPM) value, an upstroke
time interval, a down stroke time interval, and a percentage increase or
decrease in SPM as compared to a predetermined calibrated SPM (CSPM)
value. Preferably the monitor device also has means to transmit the
operating parameters wiredly or wirelessly to a remote display device such
as for example a cell phone or smart phone.
One embodiment of the present invention has the monitor device tapping
into pump control proximity or limit sensors already preexisting on a
hydraulic oil well pumping apparatus. These pump control proximity sensors
are integral to the hydraulic oil well pumping apparatus, with one proximity
switch being positioned to detect when the pump rod reaches a top-of-stroke
position (TOSP) and a second proximity switch being positioned to detect
when the pump rod reaches a bottom-of-stroke position (BOSP). The
proximity sensors create signals which are used by the pumping apparatus
controller to cause the pumping apparatus to raise and lower a pump rod
into the oil well. Thus, the monitor device is simply tapping into signals
from
pre-existing pump control proximity sensors which are normally used for a
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different purpose, namely, signalling to the pump controller when to, for
example, energize or de-energize the directional valve which causes the
movement of the pump rod to change directions.
However, the monitor device may also be used with reciprocating oil well
pumping apparatus which do not have pre-existing proximity sensors to
detect when the pump rod reaches the TOSP or BOSP, such as for example
horse head type pump apparatus. In this case, the proximity sensors need
to be mounted on the pumping apparatus and connected to the monitor
device to permit the monitor device to calculate and display the operating
parameters.
While preferred embodiments will include proximity sensors to detect both
TOSP and BOSP, permitting the monitor device to calculate upstroke time
intervals and downstroke time intervals separately, it is contemplated that
less preferred embodiments may include only one, or more than two
proximity sensors. Furthermore, it is contemplated that sensors for detecting
TOSP and BOSP other than proximity sensors may be employed, and will
be selectable from a pool of sensors based on availability and
characteristics which make them suitable for the intended function in
accordance with the present invention.
Therefore, according to one aspect of the present invention, there is
provided a device for monitoring and displaying operating parameters of a
reciprocating oil well pumping apparatus to an operator, said pumping
apparatus moving a pump rod between a top-of-stroke position (TOSP) and
a bottom-of-stroke position (BOSP), in conjunction with at least one of:
i) a first sensor for creating a first signal when said pump rod is
at said TOSP, and
ii) a second sensor for
creating a second signal when said pump
rod is at said BOSP'
said device comprising:
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a connecting means for operatively connecting said device to
said at least one of said first and second sensors;
a processor connected to said connecting means and
programmed to:
a) detect said at least one
of said first and second signals
from said at least one of said first and second sensors;
b) measure time intervals between said detected signals;
c) calculate at least one operating parameter of said
pumping apparatus based on said measured time
intervals; and
d) provide an output of said at least one operating
parameter; and
a display means for receiving said output and displaying same.
According to another aspect of the present invention, there is provided a
method of monitoring and displaying operating parameters of a reciprocating
oil well pumping apparatus to an operator, the pumping apparatus moving
a pump rod between a top-of-stroke position (TOSP) and a bottom-of-stroke-
position (BOSP), said method comprising:
detecting instances when said pump rod is at at least one of said
TOSP and said BOSP;
measuring time intervals between said instances;
calculating at least one operating parameter of said pumping
apparatus based on said measured time intervals; and
displaying said at least one operating parameter on a display means.
According to yet another aspect of the present invention there is provided
a system for monitoring and displaying operating parameters of a
reciprocating oil well pumping apparatus to an operator, said pumping
apparatus moving a pump rod between a top-of-stroke position (TOSP) and
a bottom-of-stroke position (BOSP), said system comprising:
at least one of:
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i) a first sensor for creating a first signal when said pump rod is
at said TOSP, said first sensor being adapted for mounting on
said pumping apparatus; and
ii) a second sensor for creating a second signal when said pump
rod is at said BOSP, said second sensor being adapted for
mounting on said pumping apparatus;
a monitor device operatively connected to said at least one of said
first and second sensors, said monitor device comprising:
a processor programmed to:
a) detect said at least one
of said first and second signals
from said at least one of said first and second sensors;
b) measure time intervals between said at least one first
and second signals;
c) calculate at least one operating parameter of said
pumping apparatus based on said measured time
intervals; and
d) provide an output of said at least one operating
parameter; and
a display means for receiving said output and displaying same.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference will now be made to the preferred embodiments of the present
invention with reference, by way of example only, to the following drawings
in which:
Fig. 1 is a perspective view of the monitor device according to an
embodiment of the present invention;
Fig. 2 is a schematic diagram of the back of the monitor device of Fig.
1;
Fig. 3 is a schematic diagram of the back of a monitor device
according to another embodiment of the present invention;
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Fig. 4 is a schematic diagram of a prior art hydraulic pumping
apparatus;
Fig. 5 is a schematic diagram of the monitor device of Fig. 2
connected to the pump controller of the hydraulic pumping apparatus of Fig.
4;
Fig. 6 is a schematic diagram of the monitor device of Fig. 1; and
Fig. 7 is a side view of a horse head pumping apparatus according to
an embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is described in more detail with reference to
exemplary embodiments thereof as shown in the appended drawings. While
the present invention is described below including preferred embodiments,
it should be understood that the present invention is not limited thereto.
Those of ordinary skill in the art having access to the teachings herein will
recognize additional implementations, modifications, and embodiments
which are within the scope of the present invention as disclosed and claimed
herein. In the figures, like elements are given like reference numbers. For
the purposes of clarity, not every component is labelled in every figure, nor
is every component of each embodiment of the invention shown where
illustration is not necessary to allow those of ordinary skill in the art to
understand the invention. Orientative words such as "front", "back", "top",
"bottom", and "side" as used herein are used for clarity with reference to the
orientation of elements in the figures and are not intended to be limiting.
A monitor device 10 according to the present invention is disclosed in Fig.
1. The monitor device 10 shown in Fig. 1 has on its front side 12 an on/off
toggle switch 14, a calibrate push button 16, and a display consisting of an
alpha numeric LCD screen 18 and a series of five LEDs 20.
As shown in Fig. 2, the back side 22 of the monitor device 10 is provided
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with a power connector to permit connection of the monitor device 10 to a
source of electric power for powering the monitor device 10. Examples of
preferred sources of electric power include 12 or 24 volt DC electric power
sources such as batteries 24, generators, and alternators, as well as
standard 120 or 240 volt AC electric power supplied by, for example, an
electricity generating plant. If the monitor device 10 is to be powered by 12
or 24 volt DC electric power, the preferred power connector will include a
pair of power terminals 26 to facilitate the connection to the 12 or 24 volt
DC
electric power source with suitable wires 28. If the monitor device 10 is to
Figs. 2 and 3 also show a connecting means for operatively connecting the
monitor device 10 to one or more sensors 40 for detecting one or more
positions of a pump rod 42 of a reciprocating oil well pumping apparatus.
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With reference to Fig. 4, there is shown a typical hydraulic pumping
apparatus 44 as described in U.S. Pat. No. 7,762,321 to Fesi et al. As
shown, the hydraulic pumping apparatus 44 has two sensors 40 and 40'
mounted to a frame 56. Sensor 40 is used to create a first signal when the
pump rod 42 is at the top-of-stroke position (TOSP), by detecting when the
lower end portion 58 of the coupling 60 on pump rod 42 is abeam the sensor
40. Sensor 40' is used to create second signal when the pump rod 42 is at
the bottom-of-stroke position (BOSP), by detecting when the lower end
portion 58 of the coupling 60 on pump rod 42 is abeam the sensor 40'. The
coupling 60 is connected to a sucker rod 62. In the hydraulic pumping
apparatus of Fesi et al., the sensors 40 and 40' are connected to controller
54 by wires 50, and the controller 54 uses the first and second signals to
cause the hydraulic pumping apparatus 44 to move the pump rod 42
between the TOSP and the BOSP. In other words, the sensors 40 and 40'
of the hydraulic pumping apparatus 44 are pump control sensors which
create pump control signals used by the controller 54 to operate the
hydraulic pumping apparatus 44. Fesi. et al. describes the sensors as
proximity or limit switches, examples of which are those manufactured by
Turck Company, model number N129CP40AP6X2/510, which are a type of
inductive proximity sensor. The inductive proximity sensor creates electric
signals by switching from a normally open state (i.e. electrical
discontinuity)
to closed state (i.e. electrical continuity) when triggered by, for example,
the
proximity of the lower end portion 58 of coupling 60. Other hydraulic
pumping apparatus 44 may be provided with other types of sensors, for
example, mechanical contact sensors and optical sensors, all of which
sensors are comprehended by the present invention. What is important is
that the sensor be configured to create signals when the pump rod 42 is at
the TOSP or the BOSP, which signals are detected by the monitor device
10.
Referring now to Fig. 5, there is shown a representation of the electronic bus
52 inside of the hydraulic pumping apparatus controller 54. Typically, the
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electronic bus 52 consists of a series of terminals 64 for electrically
connecting devices to the controller 54. As shown, wires 50 leading from the
pump control sensors 40 and 40' are connected to respective terminals 64
on the electronic bus 52. The back side 22 of the monitor device 10 is
shown on top of the controller 54. Wires 50 connect the two pairs of sensor
connecting terminals 48 on the monitor device 10 to the same electronic bus
terminals 64 connecting the pump control sensors 40 and 40'. Wires 28
connect the pair of power terminals 26 on the monitor device 10 to battery
24 for electric power. Accordingly, it can now be appreciated that according
to this embodiment of the present invention, the monitor device 10 taps into
the wires 50 leading from the pump control sensor 40, 40' at the electronic
bus 52 in the hydraulic pump controller 54.
As shown in Fig.6, the inside of the monitor device 10 houses a processor
66 which is connected to the sensor connecting terminals 48 and
programmed to detect the first and second signals created by the pump
control sensors 40 and 40'. The processor 66 can be a general purpose
processor, a high speed processor, an application specific integrated circuit
(ASIC), a digital signal processor, a programmable array, or the like. The
processor 66 may include, or be associated with a memory and a bus in
order to retrieve and store information in the memory. It will be appreciated
that in some configurations, the processor 66 can constitute other
interconnection being integrated together and packaged into the monitor
device 10. When the monitor device 10 is switched on with on/off switch 14,
the processor 66 measures time intervals between the detected signals, and
uses the measured time intervals to calculate at least one operating
parameter of the pumping apparatus. Once the operating parameters are
calculated, the processor 66 outputs one or more of the operating
parameters to the display means, which in the preferred embodiment
includes an LCD screen 18 and a series of five LEDs 20, as mentioned
above.
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Preferably, the operating parameters calculated by the processor 66 will
include one or more of:
a) a ratio
of a number of strokes per unit time based on the
measured time intervals, such as strokes per minute (SPM),
b) an upstroke time
interval (i.e. the length of time taken by the
pump rod 42 to move from BOSP to TOSP), and
c) a
downstroke time interval (i.e. the length of time taken by the
pump rod 42 to move from TOSP to BOSP).
The upstroke time interval is preferably calculated by measuring the time
interval between sensor 40' creating the second pump control signal
indicating the pump rod 42 is at the BOSP and sensor 40 creating the first
pump control signal indicating that the pump rod 42 is at the TOSP.
Similarly, the downstroke time interval is preferably calculated by measuring
the time interval between sensor 40 creating the first pump control signal
indicating the pump rod 42 is at the TOSP and sensor 40' creating the
second pump control signal indicating that the pump rod 42 is at the BOSP.
Most preferably, the operating parameters calculated by the processor 66
will include a percent difference between the latest SPM value calculated by
the processor 66 and a predetermined SPM value. For example, as shown
in Fig. 1, the preferred monitor device 10 is provided with a user interface
consisting of a button 16 for selecting a calibrate function which directs the
processor 66 to calculate the average of a predetermined number of stroke
per minute values, and to store the average as a calibrated SPM (CSPM)
value. While the predetermined number of SPM values which are used by
the processor 66 in calculating the CSPM value can be set to any number,
good results have been obtained with between 2 and 200 SPM values
calculated by the processor 66 following selection of the calibrate function.
According to the present invention, the calibrate function establishes a
baseline value for the strokes per minute the reciprocal oil well pumping
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apparatus is experiencing at that particular point in time. Accordingly, the
calibrate function is preferably selected when the monitor device 10 is first
installed on the reciprocal oil well pumping apparatus, and subsequently
when any adjustments are made to the oil well pumping apparatus. The
CSPM value, as then set, is used by the monitor device 10 to detect a
difference between the CSPM value and the latest SPM value calculated by
the processor 66.
Although connecting the monitor device 10 to two sensors is preferred in
order to permit sensing both TOSP and BOSP, other embodiments in which
the monitor device 10 connects to only one sensor are also comprehended
by the present invention. It will be appreciated, however, that relying on
signals from only one sensor will limit the operating parameters of the
hydraulic pumping apparatus 44 that can be measured, since at least two
sensors (i.e. one for signalling TOSP and one for signalling BOSP), are
required, for example, to measure separately the upstroke time and
downstroke time intervals. However, with one sensor the monitor device 10
can still display the ratio of stroke per unit time, and difference or percent
difference as compared to the CSPM value.
Very small changes in SPM values are difficult to detect by operators using
the prevailing method of counting pump rod strokes visually and timing them
with a stop watch. It has been found however that decreases in SPM values
as small as 0.2 relative to the CSPM value can result in substantial losses
in oil production at the well, which potentially equates to thousands of
dollars
in lost revenues. For example, assuming a $460.00/m3 oil production on a
5m3/day oil well, a 5% decrease in SPM value relative to a CSPM value of
4 represents a difference of only 0.2 strokes per minute but results in 12
lost
strokes per hour (i.e. 288 lost strokes per day) which translates to losses of
about $115 per day (i.e. $3,450/month, or $43,070/year). A 10% decrease
in SPM value relative to a CSPM value of 4 represents a difference of only
0.4 strokes per minute but results in 24 lost strokes per hour (i.e. 576 lost
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strokes per day) which translates to losses of about $230/day (i.e.
$6,900/month, or $83,950/year). Increases in SPM values are also
problematic as they can result in inefficient pumping and increased wear and
tear on the equipment.
Accordingly, as mentioned above, the processor 66 calculates a percent
difference between the CSPM and the latest SPM value and displays the
difference on the display for the operator to see. Preferably, the display
includes beside the alphanumeric LCD screen 18, a series of five LEDs 20
in proximity to each other to display the percent difference, as shown in Fig.
1. Thus illumination of the first LED 68 indicates to the operator viewing the
monitor device 10 that the latest SPM value calculated by the processor 66
is increased relative to the CSPM value by 10% or more. Illumination of the
second LED 70 indicates to the operator that the latest SPM value is
increased relative to the CSPM value by anywhere from 5% to less than
10%. Illumination of the third LED 72 indicates to the operator that the
latest
SPM value is increased or decreased relative to the CSPM value by less
than 5%. Illumination of the fourth LED 74 indicates to the operator that the
latest SPM value is decreased relative to the CSPM value by anywhere from
5% to less than 10%. Illumination of the fifth LED 76 indicates to the
operator that the latest SPM value is decreased relative to the CSPM value
by 10% or more. Although the preferred embodiment is described as
including an arrangement of five LEDs to indicate increases and decreases
in the latest SPM value relative to the CSPM value of about 0%, 5%, and
10%, other arrangements of more or less LEDs (or for that matter other
indicating or signalling devices, whether incandescent bulbs, florescent
bulbs, etc), indicating other percent increases or decreases in the latest
SPM value, are possible, all of which other arrangements are
comprehended by the present invention.
In addition to the visual indications provided by the series of five LEDs 20,
the preferred monitor device 10 includes a sound emitting device, and the
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processor is further programmed to activate the sound emitting device to
alert the operator to an alarm condition, which may be for example either an
increase or decrease in the latest SPM value of 10% or more relative to the
CSPM value. Although the sound emitting device according to the preferred
embodiment is a speaker or a horn, other sound emitting devices for
generating sounds or tones indicating other percent increases or decreases
in the latest SPM value, are possible, all of which other arrangements are
comprehended by the present invention.
Preferably, the monitor device 10 also has means for establishing a wired
or wireless connection to a remote display device 78, such as for example,
a remote computer, cellphone, or smartphone. Most preferably, the wired
or wireless connection means connects to a Supervisory Control and Data
Acquisition (SCADA) system. Shown in Fig. 6, for example, is a cellular
modem 80, which is operatively connected to the processor 66 for wirelessly
transmitting one or more of the operating parameters of the pumping
apparatus (i.e. SPM, the upstroke time interval, the downstroke time interval,
the percent difference between the CSPM value and the latest SPM value,
etc.) to the remote display device 78 for displaying the one or more
operating parameters thereon.
Although the wireless connection is preferred, the present invention also
comprehends using a network (ethernet) card, telephone modem, or the like,
in place of the cellular modem 80 to establish a wired connection to the
remote display device 78. What is important is that the preferred monitor
device 10 includes a means for establishing a wired or wireless connection
to the remote display device 78, and the processor 66 is further programmed
to transmit one or more of the operating parameters of the oil well pumping
apparatus via the wired or wireless connection to be displayed on the remote
display device 78. This will enable an operator away from the oil well
pumping apparatus to view on the remote display device 78 the same
operating parameters being displayed by the monitor device 10 at the oil well
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pumping apparatus in the field.
As mentioned above, the monitor device 10 of the present invention can also
be set up to be used with a horse head pumping apparatus 46. However,
unlike the hydraulic pumping apparatus 44 described above, the horse head
pumping apparatus 46 does not normally include pump control sensors for
signalling when the pump rod 42 is at the TOSP or the BOSP. Accordingly,
at least one of a first sensor 40 and a second sensor 40' must be mounted
on the horse head pumping apparatus 46 and connected to the monitor
device 10, for the monitor device 10 to function. As shown in Fig. 7, the
first
sensor 40 is mounted at the top of the Samson post 82, to the rear side of
bearing housing 84 (i.e. the side furthest away from horse head 86). The
second sensor 40' is also mounted at the top of the Samson post 82, but to
the front side of bearing housing 84 (i.e. the side closest to the horse head
86). In this configuration, when the walking beam 88 rotates about shaft 90
in a counter clockwise direction to its limit, pump rod 42 will be at the
TOSP,
and first sensor 40 will be triggered. When the walking beam 88 rotates
about shaft 90 in a clockwise direction to its limit, pump rod 42 will be at
the
BOSP, and the second sensor 40' will be triggered. Therefore, the first
sensor 40 creates a first signal when the pump rod 42 is at the TOSP, and
the second sensor 40' creates a second signal when the pump rod 42 is at
the BOSP.
Although the preferred first or second sensors are inductive proximity
sensors, other types of sensors may also be found to be suitable by persons
skilled in the art, for example, mechanical contact sensors and optical
sensors, all of which sensors are comprehended by the present invention.
What is important is that the sensors be configured to create signals when
the pump rod 42 is at the TOSP or the BOSP, which signals are detected by
the monitor device 10.
Accordingly, operatively connecting the monitor device 10 to the first sensor
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40 and the second sensor 40' will permit its processor 66 to calculate and
display the operating parameters of the horse head pumping apparatus 46
in the same way as described above in connection with the hydraulic
pumping apparatus 44. The only difference between how the monitor device
10 is set up for use with a hydraulic pumping apparatus 44 as compared to
a horse head pumping apparatus 46 is that the hydraulic pumping apparatus
44 has pre-existing pump control sensors 40 and 40', whereas the horse
head pumping apparatus 46 does not.
Although mounting two sensors to the horse head pumping apparatus 46 is
preferred to permit sensing of both TOSP and BOSP, less preferred
embodiments in which only one sensor is mounted are also comprehended
by the present invention. It will be appreciated, however, that relying on
signals from only one sensor will limit the operating parameters of the horse
head pumping apparatus 46 that can be measured, since at least two
sensors (i.e. one for signalling TOSP and one for signalling BOSP), are
required to measure, for example, upstroke time and downstroke time
intervals. However, with one sensor the monitor device 10 can still display
the ratio of stroke per unit time, and difference or percent difference as
compared to the CSPM value.
Having described preferred embodiments of the monitor device 10 and how
they are connected to pre-existing sensors on, for example, a hydraulic
pumping apparatus 44, or retrofit sensors on, for example, a horse head
pumping apparatus 46, it will be appreciated that at the heart of the present
invention is a method of monitoring and displaying operating parameters of
a reciprocating oil well pumping apparatus to an operator involving at least
the following steps:
a) detecting instances when the pump rod 42 is at at least one of
the TOSP and the BOSP;
b) measuring time intervals between the instances detected in
step a);
CA 02772462 2012-03-20
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c) calculating at least one operating parameter of the pumping
apparatus based on the measured time intervals; and
d) displaying the at least one operating parameter on a display.
While reference has been made to various preferred embodiments of the
invention other variations, implementations, modifications, alterations and
embodiments are comprehended by the broad scope of the appended
claims. Some of these have been discussed in detail in this specification
and others will be apparent to those skilled in the art. Those of ordinary
skill
in the art having access to the teachings herein will recognize these
additional variations, implementations, modifications, alterations and
embodiments, all of which are within the scope of the present invention,
which invention is limited only by the appended claims.
