US 3274940 A
Description (OCR text may contain errors)
P 27, 1966 R. A. COTTRELL CONTROL SYSTEM FOR WELL PUMP 2 Sheets-Sheet 1 Filed Jan. 12. 1965 @MJJOEFZOO MOKDOw mm Oa ROBERT A. COTTRELL INVENTOR.
Z4 M, WW W? Sept. 27, 1966 R. A. COTTRELL CONTROL SYSTEM FOR WELL PUMP Filed Jan. 12. 1965 2 Sheets-Sheet 2 %i W as J 40 l 52 5o i\ N FIG. 3 38 46 54 ROBERT A. COTTRELL INVENTOR United States Patent 3,274,940 CONTROL SYSTEM FOR WELL PUMP Robert A. Cottrell, Box 4066, Midland, Tex. Filed Jan. 12, 1965, Ser. No. 424,892 2 Claims. (Cl. 103-25) This invention relates to oil wells and more particularly to an automatic well cut-off 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 from the pool that gathers at the bottom of the well to the surface of the earth. A desirable mode of operation is to pump the oil whenever there is oil in the pool and to stop pumping when there is no oil in the pool.
Advantages of this desirable mode of operation are that the pump automatically reaches it optimum pumping rate with a result in a saving of man hours and other equipment. The pump thus operated operates at a greater efficiency in pump displacement, thereby reducing the total number of pumping hours which in itself results in a savings of power and power costs.
An object of this invention is to provide a control for pumping an oil well at all times if there is oil in the pool at the bottom of the Well but to stop the pumping operation if the pump ceases to pump liquid or if the well begins to flow gas. Another object of this invention is the preventation of gas locks. If the well is shut down (i.e. the well no longer pumps) after lipuids cease to flow into the pool, this prevents the pump from filling with gas to the exclusion of liquid which is an undesirable situation. This desirable result is achieved by having the well to cease pumping as soon as it ceases to pump liquid.
A further advantageous result is that if the reservoir from which the petroleum is flowing is being water flooded that it better maintains hydrastic pressure upon the formation adjacent to the well bore and results in a high recovery of petroleum and prevents the water from coneing.
Still further objects are to achieve the above with a device that is sturdy, compact, durable, simple, versatile, and reliable, yet inexpensive and easy to manufacture and operate.
Still further objects are to achieve the above with a method that is rapid, inexpensive, and does not require skilled people to operate.
The specific nature of the invention as well as other objects, uses, and advantages thereof will clearly appear from the following description and from the accompanying drawings, the different views of which are not necessarily to the same scale in which:
FIG. 1 is a schematic representation of pumping oil well with my invention connected thereto.
FIG. 2 is a sectional view of a valve as would be used in the invention.
FIG. 3 is an enlarged sectional detailed portion of the valve shown in FIG. 2.
Referring more particularly to the drawings, pump is located within well 12 deep within the ground. The pump is operated by conventional equipment including rocking beam 14 which is driven by motor 16. The motor is connected to a source of electrical power 18 through switch 20. The switch is operated by controller 22.
Fluid discharge line 24 is connected to the pump and conveys the fluids produced from the well 12 to a storage tank 25. Hydraulic pressure control valve 26 in the discharge line 24 maintains the pressure on the upstream or well side at a greater amount than the pressure on the downstream or storage side. Float chamber 28 is attached by conduit 30 to the top of the discharge line 24 at a point upstream from the pressure control valve 26 and the pump 10. The conduit 30 attaches to the bottom of the float chamber 28. Equalizing line 32 extends from the top of the float chamber 28 to the discharge line 24 downstream from the pressure control valve 26. The equalizing line is a small diameter line having only a fraction of the diameter of the discharge line 24. Float 34 in the float chamber 28 is attached by electrical switch 36 to the controller 22. The attachment is such that when there is liquid in the float chamber 28 and the float 34 rises from its bottom position, the electrical switch 36 is closed.
The hydraulic pressure control valve 26 is of the globe type having an opening with a valve seat 38 in the body of the valve (FIG. 2). The opening is normally closed by 'valve 40 in the form of a disc which seals on the valve seat to close the opening. The valve 40 is attached to rod 42 which is biased by spring 44 so that if the pressure beneath the valve is sufiicient that it lifts the valve 40 from the seat 38 permitting a discharge of fluids. The chamber 46, below the valve seat 38, is connected to the pump 10. The chamber 48, above the valve, is on the downstream side of the valve 40.
The valve 40 has a bolt 50 threaded into an opening therethrough (FIG. 3). The bolt 50 has axial bore 52 from the end to within the head which intersects diametrical bore 54 through the head which is on the lower or upstream side of valve 40 within chamber 46. The bores 52 and 54 provide an orifice or bypass fluid passageway through the valve. The bypass fluid passageway has a small diameter compared to the opening through valve seat 38. Therefore if the pump is pumping a small amount of liquid or if only gas is flowing from the well, the small amount of fluid will pass through the bypass fluid passageway without appreciably raising the pressure on the discharge line 24. Therefore the gas being produced by the well 12 accumulates in the float chamber 28 and the float 34 will be in a down position. The float 34 will be in a raised position only if the pump 10 is pumping a substantial amount of liquid. The degree of pumpoil can be adjusted by raising or lowering float level.
The bypass fluid passageway, which is open at all times connects the discharge l-ine upstream and downstream of the pressure control valve 26 so that a small flow is permitted at all times. The float 34 acts as a sensing means in the system for determining if the liquid displacement from the pump 10 is greater than can be accommodated by the bypass fluid passageway. If the liquid produced by the well 12 can be accommodated by the bypass fluid passageway the liquid will not enter the float chamber 28.
The controller 22 includes a clock mechanism for periodically starting the motor 16 by closing the switch 20. After a short period of time (such as a few minutes or less) the controller will open the switch 20 stopping the motor 16 unless the pump 10 is pumping suflicient liquid to raise the float 34. If sufiicient liquid is being produced by the well 12, the switch 20 remains closed and the pump 10 continues pumping. At such time as the pump 10 fails to pump suificient liquid to keep float 34 in the raised position, the controller 22 opens the switch 20 stopping the motor. At this time a predetermined recovery period commences again before the motor 16 is again started to determine if suflicient liquid has accumulated at the bottom of the well 12 to pump sufficient liquid to raise the float 34. A backup of fluid in the fluid chamber cannot restart the motor until the recovery time has timed out.
Inasmuch as the details of construction of the controller 22 are known to the art, they have not been shown in detail here. An example of such a controller is found in the U.S. patent to T ipton 2,316,494. It will be understood of course that the reference to Tipton is only an example of one controller and that other controllers will be within the skill of those familiar with the art.
It will be understood by those skilled in the art that normally most petroleum products have gas in solution with the liquid. However, if the system were pumping fluid without gas in solution, then in that situation when the pump fails to displace a quantity of fluid greater than the amount which can be accommodated through the bypass passageway, the differential pressure will equalize thereby dropping the fluid level in the float chamber 28, thereby dropping the float, thu opening the switch.
It will be apparent that the embodiment shown is only exemplary and that various modifications can be made in construction, materials, and arrangement within the scope of the inventions as defined in the appended claims.
I claim as my invention:
1. An oil well pumping system having (a) a pump in the well,
(b) a motor drivingly connected to the pump,
() a discharge line connected to the pump in the well,
(d) a hydraulic pressure control valve means for maintaining the hydraulic pressure on the pump at a greater amount than the pressure in the discharge line downstream the pressure control valve means when the pump is pumping liquid,
(e) a bypass fluid passageway open at all times connecting the discharge line above stream and downstream of the pressure control valve means,
(f) the bypass fluid passageway being small as compared to the opening through the pressure control valve means,
(g) sensing means attached to the system for determining if liquid displacement from the pump is greater than can be accommodated by the bypass fluid passageway,
(h) means connecting the sensing means to the motor for continuing the operation of the motor responsive to the sensing means determine that the liquid is greater than can be accommodated by the bypass fluid passageway, and
(i) said hydraulic pressure control valve means also functioning as means for maintaining a liquid level in said sensing means when said liquid displacement 4 is greater than can be accommodated by the bypass fluid passageway.
2. In an oil well pumping system having (a) a pump in the well,
(b) a motor drivingly connected to the pump,
(0) a discharge line connected to the pump in the well, and
(d) a hydraulic pressure control valve means in the discharge line for maintaining the hydraulic pressure on the pump at a predetermined amount greater than the pressure in the discharge line downstream from the pressure control valve means when the pump is pumping liquid;
the improved control for the motor comprising:
(e) a float chamber,
(f) a conduit connecting the lower portion of the float chamber to the top of the discharge line, between the pump and the hydraulic pressure control valve means,
(g) an equalizing line connecting the top of the float chamber discharge line downstream from the pressure control valve means,
(h) said pressure control valve means having an orifice therethrough permitting a small flow therethrough regardless of pressure,
(j) a float in the float chamber and (k) means connecting the float and motor for continuing the operation of the motor it the float is in the raised position.
References Cited by the Examiner UNITED STATES PATENTS 2,316,494 4/1943 Tipton 103-25 2,483,084 9/1949 Callahan 1032.6 2,550,093 4/1951 Smith 10325 2,693,196 11/1954 Hundley, 103203 X 2,761,389 9/1956 Turner 103-25 2,776,630 1/1957 Pagan 103203 2,955,173 10/1960 Kranz 10326 X 3,044,402 7/1962 Kreuter l0325 MARK NEWMAN, Primary Examiner.
SAMUEL LEVINE, Examiner.
W. L. FREEH, Assistant Examiner.