U.S. patent number 3,854,846 [Application Number 05/365,881] was granted by the patent office on 1974-12-17 for oil well pumpoff control system utilizing integration timer.
This patent grant is currently assigned to Dresser Industries, Inc.. Invention is credited to Bobby L. Douglas.
United States Patent |
3,854,846 |
Douglas |
December 17, 1974 |
OIL WELL PUMPOFF CONTROL SYSTEM UTILIZING INTEGRATION TIMER
Abstract
A valve in the production flow line of an oil well closes a reed
switch indicative of fluid being pumped through the line. The
switch closure activates a first oscillator whose count is compared
with a variable frequency oscillator having a frequency of
approximately one-half that of the first oscillator. The comparison
is made over a given period of time to ascertain the percentage of
time the valve has been open and passing fluid. Theoretically, the
valve should be open fifty percent of the time because fifty
percent of the time is taken on the downstroke of the pumping
assembly when no production is occurring. In response to the
integration timer producing a signal, a shutdown timer is turned on
which restarts the cycle after a preselected amount of time. When
the system is restarted by the shutdown timer, a pump-up timer is
turned on which is adjusted to allow for a desired pump-up time. As
the pump-up timer is allowing the system to recycle, the
integration timer is reset and the recycling is completed if the
requirements of the integration timer are met. Otherwise, the unit
is shut down again and the system recycled. A variable electronic
scaler is connected to the output of the integration timer which
monitors the output signals from the integrator timer. After the
preset number of times the integration timer produces a signal, the
scaler turns off the whole system.
Inventors: |
Douglas; Bobby L. (Dallas,
TX) |
Assignee: |
Dresser Industries, Inc.
(Dallas, TX)
|
Family
ID: |
23440768 |
Appl.
No.: |
05/365,881 |
Filed: |
June 1, 1973 |
Current U.S.
Class: |
417/12;
417/43 |
Current CPC
Class: |
E21B
37/06 (20130101); F04B 49/02 (20130101); E21B
47/009 (20200501); F04B 2205/16 (20130101); F04B
2201/02071 (20130101); F04B 2205/13 (20130101) |
Current International
Class: |
E21B
37/00 (20060101); E21B 47/00 (20060101); F04B
49/02 (20060101); E21B 37/06 (20060101); F04b
049/00 () |
Field of
Search: |
;417/12,33,43,20,44,45
;200/81.9R,81.9M ;318/326,327,318,474,481 ;331/65 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Freeh; William L.
Attorney, Agent or Firm: Johnson, Jr.; William E.
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A system for controlling the operation of a well pumping
installation including a pump, a motor for operating said pump, and
a pumped fluid flowpipe, comprising:
means responsive to the flow of fluid through said flowpipe;
signal means for generating signals indicative of said
response;
means to determine whether said signals are occurring less than a
predetermined percentage of time during a given time interval;
and
means to terminate the pumping operation in the event of said
lesser determination.
2. The system of claim 1 wherein said signal means comprises a
first oscillator having a preset frequency wavetrain output.
3. The system of claim 2 including in addition thereto, a second
oscillator having a preset frequency output.
4. The system of claim 3 wherein said means for determination
comprises means for comparing the outputs of said oscillators
during a given time interval and wherein the frequency of one of
said oscillators is approximately twice the frequency of said other
oscillator.
5. A system for controlling the operation of a well pumping
installation including a pump, a motor for operating said pump and
a pumped fluid flowpipe, comprising:
valve means responsive to the flow of fluid through said
flowpipe;
means to generate signals indicative of said response;
means to determine whether said signals are occurring less than a
predetermined percentage of time during a given time interval;
and
means to terminate the pumping operation in the event of said
lesser determination.
6. A system for controlling the operation of a well pumping
installation including a pump, a motor for operating said pump and
a pumped fluid flowpipe, comprising:
means to determine whether fluid is flowing through said flowpipe
for less than a predetermined percentage of time during a given
time interval; and
means to terminate the pumping operation in the event of said
lesser determination.
7. The system according to claim 6, including in addition thereto,
means for recycling the operation after a predetermined time
following the termination of the operation.
8. The system according to claim 7, including in addition thereto,
means for preventing recycling of the operation after such
operation has been recycled a predetermined number of times.
9. A system for controlling the operation of a well pumping
installation including a pump, a motor for operating said pump and
a pumped fluid flowpipe, comprising:
valve means responsive to the flow of fluid through said flowpipe,
said valve means including a magnet;
a valve housing assembled between sections of said flowpipe for
housing said valve;
a proximity switch arranged on said housing for activation by said
magnet;
means to generate signals in response to the closure of said
switch;
means to determine whether said signals are occurring less than a
predetermined percentage of time during a given time interval;
and
means to terminate the pumping operation in the event of said
lesser determination.
10. The system according to claim 9, wherein said means to generate
signals comprises a first oscillator having a preset frequency
wavetrain output.
11. The system according to claim 10, including in addition
thereto, a second oscillator having a preset frequency output.
12. The system according to claim 11, wherein said means for
determination comprises means for comparing the outputs of said
oscillators during a given time interval.
13. The system according to claim 11, wherein the frequency of one
of said oscillators is approximately twice the frequency of said
other oscillator.
Description
BACKGROUND OF THE INVENTION
This invention relates to oil wells and more particularly to an
automatic well cutoff system for pumping oil wells.
In the production of oil, a well is drilled to the oil bearing
strata. At the bottom of the well, a pump is installed to pump oil
to the surface of the earlth from the pool that gathers at the
bottom of the well. A desirable mode of operation is to pump the
oil whenever there is oil in the pool and to stop the pumping when
there is no oil in the pool.
Advantages of this desirable mode of operation are that the pump
automatically reaches its optimum pumping rate with a result in a
saving of man hours and equipment. The pump thus operates at a
greater efficiency in pump displacement, thereby reducing the total
number of pumping hours which in itself results in a saving of
power and power cost.
Those in the prior art have long recognized the desirability of
control systems for providing such an automatic pump-off control of
oil wells. Examples of such prior art include U.S. Pat. No.
2,550,093 to G. A. Smith and U.S. Pat. No. 2,316,494 to Tipton. In
the Smith patent, a valve activates an electrical circuit which
causes the pummp to be shut down after a predetermined time
interval in the event the produced oil ceases to flow through the
valve. In the Tipton patent, a clock is caused to run in response
to there being no produced fluid, thus causing the pump to
periodically cycle in response to the well being pumped dry.
These two patents exemplify the prior art in that various means and
systems are provided which monitor the lack of produced fluid and
which in turn cause the system to recycle in response thereto.
However, the prior art, to the best of my knowledge, has failed to
provide a system which provides satisfactory pump-off control for
the various oil well pumping facilities having varying conditions
and components thereof.
A need therefore exists in the oilfield for a means for controlling
the operation of oil well pumps in such a manner that the duration
of their pumping periods will be substantially or approximately in
accordance with the actual time periods required for the pumping
off of the wells. Such a need exists for a means of control whereby
an oil well can continue in operation so long as it is pumping oil,
but which will automatically stop when it has pumped off the oil,
or for breakage, in response to cessation of discharge of oil from
the pump.
It is therefore the primary object of the present invention to
provide a well pumping control system wherein the pump control is a
factor of the percentage of time during which oil is being pumped
during a given period;
It is also an object of the invention to provide a new and improved
well pumping control system wherein the operation of the pump is
automatically stopped when the fluid in the borehole is depleted;
and
Another object of this invention is to provide a system having a
variable timing subsystem providing greater flexibility than
heretofore known in the prior art.
The objects of the invention are accomplished, generally, by a
system which utilizes a valve in the production flow line to create
an event indicative of produced fluids within the line. The
produced event is utilized in conujunction with a timer which
determines the percentage of time during which fluid is being
produced, and based upon such determination, either allows the
system to continue or to shut down. As additional features of the
invention, means are provided for the system to recycle and to
completely shut down after a predetermined number of recycles.
These and other objects, features and advantages of the invention
will be more readily understood from the following description
taken with reference to the attached drawing, in which:
FIG. 1 is a diagrammatic sketch illustrating the component parts of
the present invention;
FIG. 2 is a view, partly in cross section, illustrating the valve
and sensor means utilized to show produced fluid within the flow
line;
FIG. 3 schematically illustrates the timing system, partly as a
flow diagram, according to the present invention; and
FIG. 4 schematically illustrates, partly in block diagram, the
electrical circuitry of the invention.
Referring now to the drawing in more detail, especially to FIG. 1,
a subsurface pump (not shown) located in well 10 is actuated in a
well-known manner by means of a sucker rod string 11, the well
fluid lifted to the surface being directed to storage through a
pipe 12. The sucker rod string 11 is reciprocated in the well by
the offsetting motion of a walking beam 13, which is driven through
a pitman 14, crank 15 and speed reducing mechanism 16 by a
prime-mover 17 such as an electric motor receiving its power
through lead 18. It should be appreciated that any suitable type of
motor or engine may be used as the prime-mover 17, for example, a
gasoline engine having its energizing ignition current supplied
through lead 18.
A valve assembly 19, shown in more detail in FIG. 2, is located
within the pipe 12 and has an electrical conductor 20 leading from
the valve assembly 19 to a controller panel 21 shown in more detail
in FIG. 3.
Referring now to FIG. 2, the valve assembly 19 is illustrated in
greater detail. This valve assembly is substantially cylindrical in
shape and has threaded connections 22 and 23 on opposite ends to
facilitate assembly within the flow pipe 12 of FIG. 1. A
cylindrical valve housing 24 constructed, for example, of plastic
and fabricated perpendicularly to the axis between threaded ends 22
and 23, has mounted on its exterior surface a proximity switch 25,
for example, a reed switch, having an electrical conductor 20
leading therefrom to the controller panel 21.
A valve 30 is located within the valve housing 24 and has an
elongated cylindrical body portion 31 and a frusto-conical section
32 at its lower end adapted to engage a frusto-conical valve seat
33 in the lower portion of the valve housing 24. Although the valve
30 could be fabricated in various ways, it should be appreciated
that it can be constructed in accordance with my co-pending U.S.
Pat. application Ser. No. 301,557, filed on Oct. 22, 1972, for
"Dual Sealing Element Valve for Oil Well Pumps and Method of Making
Same," assigned to the assignee of the present invention. The full
disclosure of said application is incorporated herein by
reference.
A magnet 35 is attached to the uppermost section of the valve body
31 and is adapted to close the proximity switch 25 whenever the
valve is lifted from the valve seat 33. A non-magnetic spring 36 is
used between the upper end of the housing 24 and the valve 30 to
spring load the valve 30 into its seating arrangement with the
valve seat 33. It should be appreciated that although the housing
24 is illustrated as being of a plastic material, other
non-magnetic housings can be used, for example, certain series of
the stainless steel family.
The lower section of the cylindrical valve housing 24 above the
valve seat 33 is enlarged with respect to the upper section of the
valve housing 24, thus forming a chamber 37 for movement of the
sealing member 32 as it rises from the valve seat 33. The periphery
of such enlarged section has two or more openings 38 and 39 to
allow fluid to pass therethrough.
In the operation of the system described with respect to FIG.'s 1
and 2, it should be appreciated that as the fluid is pumped from
the well 10, it enters the flow pipe 12 and is pumped through the
valve assembly 19. In reference especially to FIG. 2, the flow is
from the threaded end 22 towards the threaded end 23. Each time the
subsurface pump (not shown) causes a surge of fluid, the valve 30
is lifted off the valve seat 33 and the fluid passes out through
the ports 38 and 39 and on to the threaded end 23 and out through
the flow pipe 12. As the valve 30 is lifted off the valve seat 33,
the magnet 35 travels near the proximity switch 25, thereby closing
the switch and allowing the conductor 20 to be grounded.
Referring now to FIG. 3, there is illustrated in greater detail the
control panel 21. The conductor 20, which is grounded each time the
proximity switch 25 of FIG. 2 is closed, is connected into an
integrator timer 40, the output of the integrator timer 40 being
connected to a shutdown timer 41 whose output is connected to a
pump-up timer 42. The output of the integrator timer 40 is also
connected to the variable electronic scaler 45 whose output drives
a visual monitor 46 bearing the legend "EQUIPMENT MONITOR." The
output of the pump-up timer 42, through a reset line 43, causes
each of the three timers to be reset upon a recycling of the
system. It should be appreciated that the illustration of FIG. 3 is
included primarily to show the physical layout of the timing
mechanisms and the visual monitor 46. As will be explained in more
detail with respect to FIG. 4, the visual monitor 46 has any given
number of lights but the preferred number is three, bearing the
numerals 1, 2 and 3, respectively. As the signals are received
sequentially by the scaler 45 from the integrator timer circuit 40,
the lights in the monitor 46 are activated in succession to
indicate the number of times the system has been shut down. For
example, during the operation of the system, the first time the
system is shut down, the number 1 will be lighted by a red light on
the monitor 46 and the numerals 2 and 3 will be sequentially
illuminated on subsequent shutdowns. A recorder connection 47 is
provided for utilizing a strip chart recorder or the like in
providing a permanent monitor of the operation of the system.
The integration timer 40, shutdown timer 41 and pump-up timer 42
are commercially available from the Eagle Bliss Division of
Gulf-Western Industries, Ind. of 925 Lake Street, Baraboo, Wis.
53,193, such items bearing the following part numbers: integration
timer 40, Part No. HP51A6; shutdown timer 41, Part No. HP510A6; and
pump-up timer 42, Part No. HP56A6.
Referring now to FIG. 4, the electrical circuitry of the system is
illustrated in greater detail. The proximity switch 25 is shown as
applying, upon its closure, a ground to the conductor 20. The
conductor 20 is connected to one of the outputs of the oscillator
50 within the integrator timer circuit 40. The oscillator 50 can be
set at any frequency desired, but as is explained hereafter, is
preferably operating at approximately twice the frequency of the
variable frequency oscillator 51. By way of further example, the
oscillator 50 has a nominal frequency of 10 kHz and the variable
frequency oscillator 51 is set at 5 kHz. The outputs of the
oscillator 50 and the oscillator 51 are connected to digital
counters 52 and 53, respectively. The outputs of the counters 52
and 53 are connected into a comparator circuit 54. If the output of
the counter 53 exceeds the output of the counter 52, as shown by
the comparator 54, this is indicative that the system is pumping
oil less than fifty percent of the time. In response to such an
adverse comparison, the comparator 54 generates a signal which in
turn triggers the single shot multivibrator circuit 55 which in
turn is connected into other of the components of the circuitry of
FIG. 4. Although the oscillator 50 has been described as being set
at twice the frequency of the oscillator 51, other frequencies can
be used to provide different percentages. Thus, if the oscillator
50 is set at four times the frequency of the oscillator 51, then
the system ascertains whether the oil is being pumped 25 percent of
the time. It should also be appreciated that it is preferable to
provide a comparison over a given period of time, for example,
during 1 minute. This eliminates problems such as might be
occasioned by an infrequent gas bubble or the like which might
cause the valve to not come off the seat 33 upon any given stroke
of the pump. Since a percentage of fifty percent is theoretically
the perfect condition, a reasonable setting of the variable
frequency oscillator would be 4 kHz in conjunction with the 10 kHz
output of the oscillator 50. Under these conditions, a signal would
not be produced from the single shot multivibrator 55 until there
was a showing that the system was operating less than forty percent
of the time.
The output of the single shot multivibrator 55 is connected by
conductor 60 to the input of the shutdown timer 41 which can be
adjusted to any predetermined period, for example, four hours. The
output of the shutdown timer 41 is connected to the input of a
pump-up timer 42 which can also be adjusted to any preselected
time, for example, twenty minutes. The shutdown timer 41 and the
pump-up timer 42 each contains a single shot multivibrator for
producing a single pulse at their respective outputs at the
conclusion of the given time periods.
The conductor 60 is also connected to the coil 63 of a relay 64,
the other side of the coil 63 being grounded. The relay 64 has a
pair of normally open and normally closed contacts. The output of
the shutdown timer is also connected to the coil 65 of a relay 66,
the other side of the coil 65 being grounded. The relay 66 also has
a pair of normally open and normally closed contacts, The output of
the pump-up timer 42 is connected to the coil 67 of a relay 68, the
other side of the coil 67 being grounded. The relay 68 also has a
pair of normally open and normally closed contacts.
The lower normally open contact of relay 64 is connected to a power
supply, illustrated as being a battery 70 which is of adequate
voltage to maintain the relay 64 in the latched position. The lower
normally open contact of relay 66 is similarly connected to a power
supply 71 for similar reasons. The upper normally closed contact of
relay 64 is connected to a conductor 72 which in turn is connected
to the upper normally open contact of relay 66. The upper wiper arm
of relay 64 is connected to conductor 73 which is connected
directly to the prime-mover power supply 74 output. The conductor
73 is also connected to the upper wiper arm of relay 66. The lower
wiper arm of relay 64 is connected to the upper wiper arm of relay
68. The lower wiper arm of relay 66 is connected to the lower wiper
arm of relay 68. The underground side of the coil 65 in relay 66 is
connected to the lower normally closed contact of relay 68. The
upper normally closed contact of relay 68 is connected to the
ungrounded side of the coil 63 in relay 64.
The output of the single shot multivibrator 55 is also connected
through conductor 80 to the input of a variable electronic scaler
45 which, for example, produces one pulse out for each three pulses
in from the single shot multivibrator 55. The output of the scaler
45 is connected to the top of a coil 82 of a relay 83, the other
side of the coil 82 being grounded. The upper normally closed
contact of relay 83 is connected directly to the prime-mover 17.
The upper wiper arm of relay 83 is connected to conductor 72. The
lower wiper arm of relay 83 is connected to a power supply 84
suitable for latching the relay 83. the lower normally open contact
of relay 83 is connected through a spring-loaded normally closed
switch 85 back to the ungrounded side of the coil 82 of relay
83.
In the operation of the circuit of FIG. 4, there has already been
described the effect of an adverse comparison being made in the
circuit 54 to thus produce a single voltage pulse from the output
of the single shot multivibrator 55 which occurs on the conductors
60 and 80. Such a pulse appearing on the input of the shutdown
timer 41 causes the timer 41 to count for a predetermined time
interval, for example, four hours. Simultaneously with the
production of this signal upon conductor 60, the relay 64 is
momentarily energized and latched into a posistion such that the
wiper arms are in contact with the normally open contacts,
respectively. The action of the power supply 70 causes the relays
to be latched in such a position. This removes the prime-mover
power supply 74 from the prime-mover 17 and the pumping action
terminates. As soon as the preselected time of the shutdown timer
41 has expired, a single pulse is generated at the output of the
timer 41 which activates the relay 66. This causes the relay 66 to
latch in position such that the wiper arms are in contact with the
normally open contacts, respectively. This causes the output of the
prime-mover power supply 74 to be connected to the prime-mover 17
and the pumping action is again commenced. Simultaneously with the
activation of the relay 66, the output of the timer 41 is coupled
into the pump-up timer 42 which is set for a predetermined time,
for example, 20 minutes, and thereafter which generates a single
pulse of its own which is coupled back to reset the pump-up timer
42, the shutdown timer 41 and the counters 52 and 53 in the
integration timer 40. Simultaneously with this resetting operation,
the output of the pump-up timer 42 activates the relay 68 which
causes the relays 64 and 66 to be unlatched and their wiper arms to
be returned to the positions as illustrated in FIG. 4. This allows
the output of the prime-mover power supply 74 to remain connected
to the prime-mover 17 and the system has thus been recycled.
Each time the output of the single shot multivibrator 55 produces a
voltage pulse on the conductor 80, the pulse is coupled into the
variable scaler 45 which is set, by way of example, to produce a
single output pulse for each three pulses in. After the system has
been shut down three times, three pulses will have been produced by
the single shot multivibrator 55 and thus the scaler circuit 45
will produce a single pulse at its output which activates the relay
83 and which is latched in such a position by the power supply 84.
This causes the prime-mover power supply 74 to be removed from the
prime-mover 17 and the pumping action is terminated. The system
cannot be recycled at this point until the spring-loaded switch 85
is manually activated to the open position to unlatch the relay 83
and thus allow the system to be recycled.
Thus it should be appreciated that there have been described and
illustrated herein the preferred embodiments of the present
invention wherein a vastly new and improved system has been
provided for making a determination as to the percentage of time in
which fluid is being produced from an oil well, and to control the
pumping operation based upon such determination. Those skilled in
the art will recognize that modifications can be made to these
embodiments as illustrated and described. For example, other types
of valves and sensing mechanisms can be used to create an event
indicative of the flow of oil through the flow line. By way of a
specific example, the use of a float valve well known in the art
can be used to generate an electrical signal or some other such
event and such use is contemplated by the invention hereof. Such an
event can then be used to aid in the determination of the
percentage of time in which the oil is flowing through the flow
line. Likewise, while the preferred embodiment contemplates the use
of various electrical, mechanical and electro-mechanical timing
mechanisms, as well as the use of solid state devices such as the
scaler circuit 45, those skilled in the art will recognize that
equivalent devices can be used to provide the results of the
invention. For example, the entire circuitry of FIG. 4 can be
fabricated from solid state components to provide greater space
saving and cost reduction, as well as vastly improved reliability.
Furthermore although the preferred embodiment of the invention
contemplates the use of electrical signals in determining the
percentage of time in which the oil is flowing through the flow
pipe, those skilled in the art will recognize that pneumatic
signals can also be used in making such a determination. Likewise,
although not illustrated, a ramp voltage device can be used and its
amplitude compared at a given time with a known amplitude to
provide a determination of the percentage of time during which the
oil is being pumped.
* * * * *