US2975721A - Deep well pumping system - Google Patents

Description

March 21, 1961 F. E. cHANcl-:LLOR r-:T AL 2,975,721

DEEP WELL PUMPING SYSTEM Filed Dec. 22, 1958 5 SheebS-Sheei' 1 [lian-l' 1:? IGA gn [GO ga l rroeA/Ey.

Mardi 21, 1961 F. E. cHANcELLo'R ET AL 2,975,721

DEEP WELL PUMPING SYSTEM 5 Sheets-Sheekl 2 Filed Dec. 22, 1958 JE. 0. Hm/Ence INVENTORS.

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March 2l, 1961 F. E. cHANcELLoR ET AL 2,975,721

DEEP WELL PUMPING SYSTEM 5 Sheets-Sheet 3 Filed Dec. 22, 1958 im im 55W CCN N N1 i 66 m0,

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` 2,975,721 DEEP WELL PUMPINGSYSTEM Forrest E. Chancellor and Robert 0. Chancellor, both of 2917 Pierce Road, Bakersfield, Calif.

Filed Dec. 22, 1958, Ser. No. 782,252

4 Claims. (Cl. 10S-'179) This invention relates to oil well production equipment and particularly to a novel production system employing sucker rod as a pump actuating medium.

The problems inherent in the use of a string of sucker rods reaching from the top of a well to a reciprocating pump near the bottom thereof for actuating the plunger of said pump, increase with the depth of the well.

Chief among these problems isv the great weight of the sucker rod stringrwhich, added to the weight of the column of o-il lifted on the upstroke, causes the rod to stretch resiliently under its load thus reducing the vertical movement transmitted to the pump plunger by a given Vertical reciprocation of the top end of the string.

arent The tremendous stresses set up in the upper portions of the sucker rody string also induces metal fatigue reducing the working life of the rod and causing costly Thehrecent practice, of extending wells to greater and greater depths Ysimply aggravates Many production systemshave therefore been devised .to eliminate the oil production troubles caused-by sucker rods, by simply eliminating the sucker rod. As yet,

however, no substitute' has been evolved which is superior to sucker rod actuated pumps in the deeper wells notwithstanding their drawbacks.

. ltisa primary object of the present invention to provide a deep well pumping system employingsucker rods as amotion transmitting medium, which will substantially reduce the problems heretofore caused in'such systems ,bysucker rod stretch and metal fatigue.

Still another object is to provide a novel rectilinear motion. reversing transmission by which one section of the sucker rod string may be lifted in performing a pump upstroke, by the weight of a descending adjacent section i of the sucker rod string.

A further, object of the invention is A"to provide such a transmission which embodies therein a pump which is actuated by said transmission.

Another object of the inventionis to eliminate, or substantially reduce the amount of, the counter weight employed in the reciprocator at the top of the well, and reduce the amount of power required to operate said reciprocator.

Yet another object is to utilize a substantial portion of the hydrostatic load in one section of the well to counter'balance and assist in lifting the hydrostatic load in another section of the well.`

i The manner of vac'zcom-plishing the foregoing objects as well as further objects and advantages will be made manifest in the following description taken in connection with the accompanying drawings, in which:

Fig. lisa diagrammatic vertical sectional View through i a Well and illustrating the installation therein of a preferredembodiment of the invention.

Figs. 2 and 2a comprise a single enlarged vertical 2,975,721 Patented Mar. 21, 1961 ice 2-2 of Fig. 1. This view shows the pumping system of the -invention as the parts thereof appear at the beginning of a downstroke in the upper section thereof.

Figs. 3 and 3a comprise a diagrammatic Vertical sectional vieW of the invention shown in Figs. 2 and 2a and illustrate the elements of the invention Apositioned as at the conclusion of a downstroke of the upper sucker rod string.

Fig. 4 is an enlarged horizontal sectional view taken on the line 4 4 of Pig. 2 and illustrates the construction of the upper transmission head of the invention.

Fig. 5 is an enlarged horizontal sectional View taken on the line 5-5 of Fig. 2 and illustrates the internal construction of the upper piston of the transmission of the invention.

Fig. 5a is a diagrammatic enlarged vertical sectional View taken on the line Saz-5a of Fig. l and showing the valved plunger and standing valve of the lower level pump of the invention.

Figs. 6 and 6a comprise a single `diagrammatic operational view similar to that in Figs. 3 and 3a but illustrating the parts of the invention positioned as at the conclusion of an upstroke of the upper sucker rod string of the system.

Fig. 7 is an enlarged horizontal sectional view taken on the line '7-7 of Fig. 2a and illustrates the construction of the lower piston of the transmission of the invention and the annular cylinder in which this operates.

Fig. 8 is an enlarged horizontal sectional view taken on the line 8 8 of Fig. 2a and illustrates the supporting spider for the lower sucker rod string of the system.

Referring specifically to the drawings, the preferred embodiment of the invention illustrated therein comprises a deep well pumping system 11i which is installed in a casingll provided in a deep well 12.. Mounted at the upper end of the well 12 on the surface of the ground isa sucker rod string reciprocator 13.

The system 10 includes an upper pump tubing string 14, a lower portion of which may beformed by an auxiliary pump barrel 15 of an auxiliary pump 16. The lower end of the barrel 15 connects to the upper end of a combination rectilinear motion transmission and pump 17, the lower end of which connects to a lower pump tubing string 18, the lower end of which in turn connects with the barrel 19 of a lower pump 2d. The barrel 19 may connect at its lower end to a perforated pipe 25 through which oil 26 in the lower end of casing 11 is drawn into the pump 2d in the operation of the system 10.

Suspended at its upper end on the walking beam of the reciprocator 13 is an upper sucker rod string 27 which extends downwardly through the upper pump tubing string 14 to connect at its lower end with a pump plunger 28 which is slidably disposed within the barrel 'l5 of auxiliary pump 16. The plunger 28 has a tapered lower end 29 in which holes 30 are formed which communicate with a central passage 31 the upper end of which communi- Cates with passages 32 in a cage 33 the upper end of which connects with the sucker rod string 27. A traveling ball valve 34. is eonned in the cage 33 and permits a ow of production uid through the plunger 2S only in an upward direction. The plunger 2S has a series of sealing cups 35 which make a sealing engagement between the plunger 2S andthe inner surface of the auxiliary pump barrel 15.

The combination transmission and pump 17 includes a cylindrical shell 40 which is internally threaded at its upper end so that an upper head v41 may screw into this shell. Screwed onto the upper end of the head 41 is an adapter 42 which is connected by a coupling 43 to the lower end of pump bar-rel 15. The head 41 is protn vided with a central bore 44 having grooves receiving O-rings 45 to form a iluid tight tit between said bore and a solid piston stem 46 which is vertically slidable in said bore. The head 41 also has a series of vertical holes 47 the upper ends of which provide seats for standing valve balls 4S which are loosely confined by cages 49 over said seats.

The lower end of cylindrical shell 40 connects through an internally and externally tapered section 54 with a pair of coaxial tubes 55 and 56.

The lower end of tube 56 extends `downwardly below the lower end of tube 55 and is internally threaded so that a lower transmission head 57 may be screwed therein. A free passage 58 is thus left between the lower end of tube 55 and head 57. The lower end of head 57 screws into the upper end of an elongated adapter 59 the lower end of which threadedly connects with the upper end of lower pump tubing string 1S. The head 57 has a central bore 60 into the counter-bored and tapped upper end of which the lower end of a tubular quill 61 A is screwed. The outside diameter of quill 61 is much smaller than the inside diameter of the tube 55 so that there is an ample annular communication passage formed between the passage 58 and the lower end of cylindrical shell 40.

Slidable in an upper piston chamber 62 formed by the shell 40 is an upper transmission piston 63 which also forms the pump plunger of the pump portion of the combined transmission and pump 17. Piston 63 is externally grooved to receive O-rings 69 which make a uid tight fit between this piston and the shell 40. The piston also has a short tapped lower bore 70 and an upper bore 71, the upper end of which has a tapped counter-bore 72 to threadedly receive the lower end of piston stem 46. A traveling valve ball 73 is trapped in bore 71 by stem 46 in operative relation with a seat 74 provided between the bores 70 and 71.

Screwed into the lower tapped bore 70 of the piston 63 is the threaded upper end of a lower tubular piston stem 75, the lower end of which telescopically receives and makes a close sliding fit with the quill 61. The lower end of -stem 75 and the upper end of quill 61 are internally and externally grooved respectively to receive O- rings 76 and 77 to make a tight sealed connection between said stem and said quill. Angled ports 78 are formed in the piston 63 to communicate between the bore 71 and the upper end of the piston.

The coaxial tubes 55 and 56 unite to form an annular lower transmission piston chamber 83, the upper end of which is vented to the atmosphere by holes 84. Vertically slidable in piston chamber 83 is an annular piston 85 which is internally `and externally grooved to receive O-rings 86 and 87 which form a uid tight fit between this piston and the coaxial tubes 55 and 56. Extending through vertical holes 88 in the piston 85 and secured thereto by nuts 89 is a series of rods 90 which also extend slidably downward through corresponding holes 91 provided in the transmission head 57 to where their lower ends are united with a spider 92 from which the upper end of a lower sucker rod string 97 is suspended. The holes 91 in head 57 are internally grooved to receive O-rings 98 which make a uid tight seal between the head 57 and rods 90.

The lower rod string 97 extends downwardly through the lower pump tubing string 18 to where the lower end of said rod string connects to a valved plunger 20a of the lower pump 20, also having the usual standing valve 20b which is provided therein at the lower end of pump barrel 19.

A body of transmission operating oil 99 is contined in the lower portion of piston chamber 83 beneath the annular piston 85 and this oil also fills the space between the tube 55 and the quill 61 and hollow stem 75, and extends up into the lower portion of the upper piston chamber 62 so that piston 63 rests on top of the operating oil 99 and is vertically slidable in the chamber 62 in reversed reciprocating relation with the piston 85. Thus, whenever the total weight pulling downwardly on piston is greater than that pushing down on piston 63 the piston 85 moves downwardly in cylinder 83 and the piston 63 moves upwardly in the cylinder chamber 62. When the quantitative relation of the loads imposed on pistons 63 and 85 are reversed, their relative reciprocal movements are reversed. The body of oil 99 is just sufficient in quantity so that when the piston 85 is near the lower end of piston chamber 83 the piston 63 is near the upper end of piston chamber 62, and vice versa.

While the specific deep well pumping system 10 disclosed herein is for illustrative purposes only, this specific system preferably has the following dimensions, Assuming that the pump tubing strings 14 and 18 are 27/8 inches outside diameter; the maximum outside diameter of the transmission-pump unit 17 is preferably 51/2 inches; the upper sucker rod string 27 is approximately 4,000 feet in length; the pump barrel 15 is preferably about l2 feet in length; the chamber 62 is about 9 feet in length; the chamber 83 is about 8 feet in length; and the adapter 59 in the portion thereof having its maximum diameter is about 8 feet in length; and the lower sucker rod string 97 is about 3,000 feet in length. It should thus be borne in mind that the weight of the upper sucker rod string 27 is about one and one-third times that of the lower sticker rod string 97.

Portions of the system 10, shown in Figs. 2 and 2a, are omitted at breaks shown therein so as to compress the details of the structure of this system into these two views, whereby the details are illustrated at a scale which show these clearly. Operational Figs. 3 and 3a and operational Figs. 6 and 6a, however, are drawn diagrammatically without any structural break longitudinally therein, and with the chamber 62, chamber 83 and adapter S9 reduced to about one-third the proportionate lengths they would have in these views if dimensioned to scale as above indicated as preferable. This distortion is adopted in order to facilitate the graphic illustration of the operation of the system.

Operation The system 10 is actuated by the recprocator 13 vertically reciprocating the upper sucker rod string 27. No counterbalance for this string is provided on the reciprocator. At the end of each upstroke of rod string 27, the plunger 28 of the auxiliary pump 16 is disposed near the top of barrel 15. The other parts of the system are at this time also positioned approximately as shown in Figs. 6 and 6a. In other words, the upper piston 63 of the transmission-pump unit 17 is near the top of the piston chamber v62; the annular piston 85 is near the bottom end of the annular piston chamber 83; and the supporting spider of the lower rod string 97 is disposed near the lower end of the lower adapter 59.

The upward travel of the upper piston 63 during the upstroke of the upper rod string 27 results from the fact that the weight of lower rod string 97 is pulling down through the rods on the annular lower piston 85 and forcing operating oil 99 upwardly against the bottom of upper piston 63 at a time when the downward pressure of the production fiuid in the upper pump tubing string 14 is taken ott of piston 63 and stem 46 by the upward movement of the plunger 28 which is suspended on and embodied with the lower end of upper rod string 27 so as to be a part of said upper rod string and function as a compression element therein.

When the rod string 27 halts at the upper end of its upstroke and starts downwardly, the full weight of the upper rod string 27 and the pressure head of the column of production fluid in upper tubing string 14 is immediately imposed on the stem 46 and upper piston 63 ofthe transmission-pump unit 17. This halts the upward movement of the upper piston 63 and the elements associated therewith and causes the standing valve `balls 48 to close. During the downstroke of the rod string l27, the traveling valve 34 opens allowing the production uid below plunger 28 to pass upwardly therethrough while the lower tapered end 29 of the plunger remains in engagement with the upper end of upper piston stem 46. The weight of the upper rod string 27 is thus added to the hydrostatic pressure of the production iluid in upper tubing string 14 imposed on `solid stem 46, so as to force the oil 99 in the chamber 62 beneath the piston 63 downwardly and through the annular passage 58 outwardly and up under the annular lower piston 35. The relative pressure areas of the upper and lower pistons 47 and 8S and the relative weights of the upper and lower rod strings 27 and 97 `and the relative weights of the upper and lower production liquid columns are designed to cause the lower rod string and production liquid column to be lifted by the piston 85.

The lifting of the rod string 97 lifts the plungerin the lower pump 20 so as to force production fluid (oil 26') upwardly through the lower pump tubing string 1S, the adapter 59, the quill 61, and the hollow stem 7S, thereby lifting the traveling valve ball 7'3 and allowing this production fluid to liow upwardly through the bore 71 and angled ports 78 into the chamber 62 above the piston 63. The relative piston and pump plunger displacements in the system 10 are calculated so as to force an amount of production fluid upwardly through travelling valve 73,

Vduring the downstroke of rod string 27, as to just ll the space in the upper end of the `chamber 62 which is evacuated by the downward' movement of piston 63. With this nice adjustment, the standing valve balls 48 will not open during this stroke. lia-slight amount of production fluid in excess of that required Vto iill the evacu-- ated upper portionof `chamber l62 'is 'delivered thereto during the stroke being described, this excess may escape upwardly through the standing valves 48 into the lower end of pump barrel without impeding the operation of the system.

The approach of the upper rod string 27 to the lower end of its downstroke is illustrated in Figs. 3 and 3a. After traveling a slight distance further downward, the rod 27 halts and starts on its upstroke. When this happens the traveling valve 34 of auxiliary pump plunger 2S immediately closes and the rising plunger carries upwardly with it the entire column of production fluid conlined in the upper pump tubing string 14 above this plunger. This relieves the piston 63 and the stern 46 of the hydrostatic pressure of this lluid column as well as the weight of sucker rod string 27 and causes the weight of the lower rod string 97 to start sinking in the production fluid in the lower pump tubing string 18 thereby returning the plunger (not shown) in the pump 20 to the lower end of the barrel 19. The weight of the rod 97, of course, is much greater than necessary to lower the piston 8S to the lower end of the piston chamber 83 and force the operating oil 99 from beneath this piston upwardly under the piston 63 so as to lift this back to'the upper end of chamber 62 and expel the production Huid, delivered to the upper end of this chamber in the immediately previous stroke, upwardly through the standing valves 48 into the lower end of the barrel 15 of auxiliary pump 16 at the bottom of pump tubing string 14. This uid iills the space between the head 41 and the auxiliary plunger 23 as the latter travels upwardly in the upstroke of the rod string 27 and the weight of lower sucker rod 97 forces piston stem 46 up against auxiliary plunger 28 with such a tremendous pressure as to support a substantial portion of the weight of upper sucker rod Z7 during the up stroke of the latter.

A complete cycle of the operation of the deep well pumping system 10 has now been described. This shows how a well 7,000 feet deep maybe pumped by the present invention without using a sucker rod string in excess A6 of Y4,000 feet in length. This greatly increases the life of the sucker rod and the efliciency of the pumping operation due to the fact that the stretching and fatigue experienced when using a rod string 7,000 feet in length is greatly reduced in this system.

While it is preferred to use an auxiliary pump 16 inthe system 10 as shown and described herein, it is to be understood that the system may operate without such a pump, in which case the lower end of rod string 27 will connect directly with the upper end of the stern 46 of the piston `63. In such a case, the descent .of the rod string 27 in its downstroke imposes the weight of this string directly on the stem 46 and piston 63 causing the latter to function exactly as above described. On the upstroke of the rod string 27, in the suggested modification, Vthis rod will lift directly on the stem 46 and piston 63, and the latter will operate as a pump plunger to support the column of production lluid contained the entire upper drill tubing string 14 in the same manner that the plunger 28 of auxiliary pump 16 supports said column in the operation of the preferred embodiment disclosed herein.

From the above description of a preferred embodiment of the invention, it is shown how this lifts oil in two stages the full height of the well with slightly more than half the amount of power which is required to lift oil in a single stage said full height. Thus a great saving is effected in the investment in power plant and in monthly operating costs.

This increased eliciency results largely from the counter balancing and counter-actuating of tandem rod string sections by a reciprocator connecting only with the uppermost section V'and by relating the two sections through a rectilinear motion reversing transmission.

Another important factor in thel increase of eliciency attained is the employing of a substantial portion of the hydrostatic head in the upper pump tubing string, bearing as it does on stem 46, during the upper rod string downstroke, to assist in lifting the production iluid column in the lower tubing string.

While the preferred system 10 herein disclosed employs only a single transrnission-pump unit 17, it is to be understood that the invention includes the concept ofusing any desired number of these units in tandem arrangement in a single well pumping system. Thus, for example, if another unit 17 were added to the system 10, it could be done by shortening rod string 97 to 1700; shortening rod string 27 to 2300; and then connecting string 27 through the second transmission-pump unit 17 with a new upper rod string, 3000 long, which would be actuated by the reciprocator 13.

What is claimed is:

l. In a pumping system for a deep well, the combination of: a sucker rod string reciprocator at an upper level of said well; upper and lower pump tubing strings arranged in tandem spaced relation in said well; upper and lower sucker rod strings arranged in tandem spaced relation within said tubing strings and with said upper rod string suspended from and reciprocated by said reciprocator; a plunger pump disposed at a lower level of said well, said pump having a barrel connected to the lower end of said lower pump tubing string with a standing valve at the lower end of said barrel, said pump also having a valved plunger connected to the bottom of said lower rod string and reciprocable vertically within said barrel; a combination transmission and pump unit interposed between and uniting juxtaposed ends of said upper and lower pump tubing strings, said unit including a rectilinear motion transmission means which is operatively associated with said sucker rod strings and supports the same and connterbalances one against the other, the upper rod string being heavier than the lower rod string, a downstroke of the upper rod string functioning through said transmission means to produce an up stroke of the 7 lower rod string and vice versa, said unit also including an intermediate level pump means which is actuated by said transmission means in response to movement of said upper rod string, firstly, in a suction stroke, which takes place concurrently with the up stroke of said lower rod string and causes said intermediate level pump means to suck in a charge of production liquid from said lower pump tubing string, and secondly, in a discharge stroke concurrent with the upstroke of said upper sucker rod string to discharge said charge of liquid upwardly into said upper pump tubing string, said unit including means for also subjecting said transmission to the weight of a column of production liquid in said upper pump tubing string, in addition to the weight of said upper rod string, during the down stroke of said upper rod string whereby said column counterbalances a similar column of production liquid occupying said lower pump tubing string and being elevated by the concurrent up stroke of said lower sucker rod string.

2. A combination as in claim l in which said intermediate pump includes a cylinder having a centrally apertured upper head constituting the bottom for said upper pump tubing string, a piston vertically reciprocable in said cylinder, a stem fixed on said piston and extending slidably upwardly through the central aperture in said head, check valve means in said head for discharging production liquid from said cylinder into said upper pump tubing string during the discharge stroke of said intermediate level pump, a lower unit head forming the top of the space enclosed by said lower pump tubing string, and a valved quill provided on said piston and slidably related with said lower head to provide a valved passage connecting said lower tubing string space with the chamber enclosed by said cylinder above said piston,

said stem comprising the means for subjecting said transmission to the weight of said upper production liquid column and abutting against said upper rod string so as to bear the weight of the latter.

3. A combination as in claim 2 in which sad intermediate level pump cylinder and piston also comprise an upper cylinder and piston of said transmission, the latter also including a lower cylinder and piston, closed passage means connecting the chambers formed by said cylinders beneath their respective pistons, a body of operating liquid occupying said chambers and passage means, and rod means extending slidably through said lower head and connecting said lower piston with the upper end of said lower sucker rod string. I

4. A combination as in claim 2 in which an auxiliary plunger pump having a barrel and a valve plunger slidable therein is associated with said unit, said barrel connecting the upper end of said unit with the lower end of said upper pump tubing string, said plunger being suspended on the lower end of said upper rod string and resting downwardly on but not being connected with said piston stem.

p References Cited in the tile of this patent UNITED STATES PATENTS 1,304,330 Laursen May 20, 1919 1,568,447 Forsyth Ian. 5, 1926 2,079,996 Humason May 11, 1937 2,490,118 Dickinson Dec. 6, 1949 2,747,511 Turner et al. May 29, 1956 2,918,014 Gould Dec. 22, 1959 FOREIGN PATENTS 612,776 France Aug. 7, 1926

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