US2059508A - Deep well pump - Google Patents

Description

Nov. 3, 1936. R. L CHENAULT DEEP WELL PUMP Filed NOV. 19, 1935 Patented Nov. 3, 1936y DEEP WELL PUMP Roy L. Chenault, Pittsburgh, Pa., assigner to Guit Research & Development Company, Pittsburgh, Pa., a corporation of Delaware Application November 19, 1935,-Serlal No. 50,580 s claims. (cl. 10a- 234),

l This invention relates to deep well pumps, and it comprises a pump having a displacement chamber submerged in the liquid of a well and from which chamber the liquid is forced by pneumatic,

pressure to the surface of the well through a reciprocable eduction pipe which includes valve means at its lower end for alternately admitting a. limited amount of liquid to the displacement chamber and then establishing communication with a source of pneumatic pressure for expelling the liquid therefrom into the eduction pipe, the valve means having a sealing partition to prevent rise of the liquid to an undesirable height in the pump when the inlet of the displacement chamber is opened, a bypass around the sealing partition which is opened when the valve means is reciprocated to close the inlet of the displacement chamber, whereby liquid confined below the sealing partition during filling of the displacement chamber will be discharged through such bypass into the upper part of the eduction pipe and will be expelled to the surface under normal, available gas pressure in a succession of slugs which do not exceed a determinable maximum weight, regardless of high liquid level in the well or high formation pressure; all as more fully hereinafter set forth and as claimed.

My prior Patent No. 1,890,720, discloses pneumatic pumping apparatus of which the present invention is an improvement. The general type of pump there disclosed is particularly adapted for oil well operation in which the oil is raised in stages and discharged in the form of slugs under pressure of gas forced into the well tubing. The oil is admitted at intervals to a displacement chamber through a valved inlet and when the `chamber is filled with liquid, the valve is closed and gas is admitted to discharge it to the surface through a ball check valve in the eduction pipe. 10 Thus, in operation, the displacement chamber is alternately filled and emptied, and the oil is discharged from the well in a series of slugs.

As long as the pressure above the check valve in the eduction pipe can be maintained at a 45 higher value than the submergence pressure which acts to open the valve the displacement chamber and tube string will not be lled to a height requiring greater ithan normal working pressure to expel the liquid. With high sub- 50 mergence head, however, a much greaterpressure is required to start pumping after a shutdown than is necessary to continue the operation, and in some instances the available pressure is insumcient, with the result that pumping can- 55 not be resumed.

In oil well operations production may be small but formation pressure high enough to build up a 'high liquid level when the pump is shut down. Such a condition exists in the East Texas field where under proration requirements the allow- 5 able production is small and it is accordingly preferable in operating to submerge the pump in several hundred feet of oil in order to obviate frequent resetting as the level drops. Moreover, it is necessaryto produce at a low rate, and if 10 continuous operation is maintained the tubing must be allowed to remain in thedown position for several minutes during each cycle to prevent waste of gas which, in the up position, is vented from the displacement chamber. In the down 15 position of the tubing, however, the displacement chamber is relieved of pressure, and the tubing may consequently fill practically to theI liquid level of the well. If the time is shorter, somewhat less oil is taken into the pump and a shorter 20 slug is consequently delivered, but where slugs of varying length and therefore of varying weight are discharged, the pressure requirements fluctuate and the resulting operation is less economical. 25

It is desirable that the slug length be substantially uniform so that the gas pressure required for pumping may be determined and fairly constant.

My present invention attains its object of re- 30 liable and economical operation by insuring that the liquid slugs which are ejected by the pump Will not be of greater weight than can be handled by the available gas pressure at the Well.

Another object which is accomplished is to 35 provide an eduction pipe divided by a sealing partition into sections which are out of communication with each other when liquid enters the pump from the well, but `which communicate through a bypass around the partition when the liquid 40 inlet is cut off, thereby to permit discharge of the liquid confined below the partition through such bypass to the surface of the well under available pressure.

A further` object is to provide a deep well pump in which the liquid from the well will not rise above a predetermined and desirable level notwithstanding conditions of submergence head or intermittent operation.

A still further object is to provide a deep well pump in which a determinable, maximum quantity of liquid is admitted in each cycle of operation and is then discharged by gas pressure, the liquid being thereby raised to the surface in a succession of slugs of substantially uniform weight.

Other and further objects will be apparent from the following description andY drawing wherein Figs. 1, 1-a and l-b are vertical sectional views of the upper, intermediate and lower portions of the pump valve assembly and-are to be considered as constituting a continuous structure:

Fig. 2 is a horizontal sectional view along the line 2-2 of Fig. l-a.

Fig. 3 is a vertical sectional view of the intermediate portion of a modiiied form of pump valve, in the region corresponding to that shown in Fig. l-a.

Referring more particularly to the drawing, the pumpvalve assembly comprises inner and outer concentric strings of tubing consisting of axially aligned and connected pipev sections. Only the lower part of the pump assembly is shown in the drawing wherein, for clarity of illustration, the consecutive portions of the pump are shown separately.

The outer string of tubing I0 includes ,the aligned pipe sections II and I2 which are connected by a threaded nipple I3. (Figs. 1 and l-a.) At its lower end, the pipe section I2 threadedly receives anY extension I4 which, as shown in Fig. 1b, constitutes an enlarged displacement chamber into which uid is admitted from the well upon reciprocation of the inner tube string to be described.

The nipple I3 has opposite tubular extensions I5 and I5 which extend into the pipe sections and I2 respectively and are supported at their ends within the outer tube string by lugs |1 and I8. The -nipple I3 and its extensions together constitute a valve cylinder in which a. reciprocating piston-type valve |9 is slidably received.

The piston valve I9 is attached to the inner tube string 20 at its upper end and at its opposite end has a tubular extension 2| (Fig. 1-b) terminating in a head 22 which slides in sleeve 23 of reduced diameter extending downwardly from the displacement chamber I4. The sleeve 23 has ports 24 for admission of well uid to the' displacement chamber when the piston valve is in. In the upper position of thev lower position. valve. as shown in Fig. 1--b, the head 22 seals the inlet of the displacement chamber.

Ports 25 extend through the wall of the piston valve extension 2| and provide communication between the displacement chamber and the interior of the piston valve which constitutes an eduction passageway from the displacement chamber.

The body of the piston valve may conveniently have portions of reduced diameter to define spaces between it and valve cylinder. The portions of piston not so reduced constitute heads which may be packed to prevent leakage of liquid from the spaces so defined. A sealing partition 26 divides the piston valve into upper and The upper portion of the piston valve as shown in Fig. 1 may be formed with ports 35 through which gas under pressure may be injected from the surface of the well when the head 31 is moved downwardly from the position shown, whereupon gas will iiow through ports 38 and the annular space 38 around the valve into the eduction passageway through the ports 35 to assist in raising the liquid to the surface. y

In the pomtion of the valve shown in Fig. 1 the ports 38 are opened for the flow of gas under pressure from the surface of the well to the space 39 around one of the reduced portions of the piston valve. As shown in Fig. 1a, the ports 48 are also open to admit gas to the space 4| and around the radially spaced arms 42 into the displacementchamber.

The radial arms .42 (Figs. l-a and 2) have l ports'43 which extend to the outside of pipe I2 for a purpose to be presently described.

Assuming that the pump displacement chamber is filled with liquid and the valve is in the position shown in the drawing, gas under pressure is forced from the surface of the well between the inner and outer tube strings, downwardly through ports 35, space 39 and ports 48 into the space 4| which communicates with the interior of the displacement chamber. The downward pressure of gas on the liquid contained in the chamber will force it through the ports 25 upwardly into the valve extension 2|. The liquid cannot flow past partition 25 in the pump valve, so consequently its path of ilow is through ports 28, space 30 and ports 32 into the annular space 33 from which it passes through ports 3| and the space 29 around the valve to the upper ports 21 and back into the eduction passageway above the partition 25. From here it may rise freely to the surface of the well or, as described below, may be given additional impetus on the succeeding down stroke .of the plunger'by gas mjecte through the ports 36-35 from the source of pressure at the surface of the well.

The displacement chamber now being emptied the pump valve assembly is reciprocated to the down position. In the down position, the piston head 31 comes to rest below ports 36 and cuts off the flow of gas to the displacement chamber via space 39. In the embodiment shown, when the head 31 has come to rest in the down position, space 38 is brought into registry with ports 36 to permit gas from the source of pressure to pass fromy ports 38 through space 38 and ports 35, where it enters the eduction passageway above the sealing partition 26 and expels any oil above this point by air lift. 'I'he same movement of the valve vents the displacement chamber by' relieving it of gas pressure, the gas flowing therefrom through space 4|, ports 40 (Fig. l-a) and space 39 around the' valve to the radial exhaust ports 43. y

'I'he pressure within the displacement chamber being thus relieved, the foot valve shown in Fig. 1b is nowin the lower position, and inlet ports 24 are uncovered to admit liquid from the well which flows up into the displacement chamber and into the pipe 2|. If the well has high liquid level the pump will ordinarily tend to ll to that high level, but in accordance with my invention its rise is limited by the partition 26. In this intake position of the valve the ports 32 are closed, and the liquid rising through the eduction passage and passing out through ports 28 will not be bypassed around the partition. Thus, notconfined below the partition 26 is calculated to be expelled by normal available gas pressure, whereas without this arrangement and construction of pump elements, it could rise to a higher level, in which case its weight might be sumcient to prevent pumping by the pressure available at the well. The liquid which is received within the displacement chamber and that portion at the piping below the partition '26 is of determinable maximum lmass `and weight, and as it is transferred from the lower section to the upper section ofthe eductlon passage in the valve at each cycle of reciprocation it is discharged to the surface of the well in a successionof liquid slugs of uniform length, or under varying conditions, of definite maximum weight.

A modied form of the invention is shown in Fig. 3 wherein an outer tube 50 mounts a valve cylinder 5I spacedl from its interior wall. The valve cylinder 5I receives a tubular reciprocating valve 52 which has ports 5I and 54 on opposite sides of the partition or seal 55. Valve cylinder 5i has a portion of enlarged internal diameter dening an annular space 5B around the piston which establishes communication between the ports 53 and 54 when the valve is in the position shown and which cuts ofi communication between the two when the valve is in lowered pd-V sition. This modified form of valve carries a foot valve such as is illustrated in Fig. 1b of the drawing.

In both the preferred and modified pump structures herein described, the ports 35 (Fig. l) throughwhich gas is admitted under pressure to assist in raising the liquid to the surface after it has been transferred to the upper section of the eductlon pipe above the partition may be omitted without departure from the invention.

lErom.l the foregoing it will be apparent that my invention provides a pneumatically operated deep well pump with means for limiting the capacity of its intake and consequently permitting operation under normal, available pressure whereby the liquid is discharged in slugs of determinable and desirable weight.

What I claim is:-

l. A deep well pump comprising a tube string, a displacement chambercarried thereby to extend into the liquid in a well, a source of pneumatic pressure, a reciprocable eductlon pipe,

valve means actuated by reciprocation of the` eductlon pipe for alternately admitting liquid from the well to the displacement chamber while venting the same, and expelling such -liquid therefrom under pneumatic pressure from said source, a, sealing partition in said eductlon pipe to limit theamount oi liquid admitted in the successive reciprocations of such pipe, a by-pass around said partition and valve means actuated by reciprocation of said eduction pipe to close the by-pass while liquid from the well is 'being admitted to said displacement chamber` and to dividing said yeductlon pipe into upper and lower` sections, a displacement chamber carried by the tube string in communication with the eductlon pipe below said partition, an inlet valve under control of the eductlon pipe for admitting liquid to the displacement chamber, valve means associated with said eductlon pipe for admitting gas under pressure to the displacement chamber when the inlet valve is closed, and alternately to that section of the eductlon pipe above said partition, further valve means associated with said eductlon pipe for bypassing said partition intermittently as the eductlon pipe is reciprocated and the inlet valve closed, thereby to permit liquid to be expelled from the displacement chamber and around said partition into the section of eductlon pipe thereabove wherein upon continued reciprocation of the eductlon pipe gas is injected to assist in discharging the liquid so transferred .and will deliver it to the surface as a slug of determinable, maximum Weight.

3. A deep well pump comprising a tube string,

a displacement chamber carried by said tube .string and adapted to extend into the liquid in a ternately admitting gas under pressure to said displacement chamber and expelling the retained liquid therefrom then stopping the passage of gas to said displacement chamber whileA admitting gas under pressure to the upper portion of the eductlon pipe, a sealing partition in the eductlon pipe to limit the rise of liquid therein when the inlet valve is opened, means for bypassing said partition upon reciprocation of said eduction pipe to close the inlet valve and admitting gas under pressure to said displacement chamber, thereby to force the conned liquid from the displacement chamber through such bypass and into said eduction pipe above said partition, and ports opened by reciprocation of said eduction pipe at the same time the inlet valve is opened for venting the displacement chamber and relieving it oi pressure whereby it is relled with liquid from the well d. Pumping apparatus comprising a displacement chamber adapted to extend into the liquid oi' a Well, a valve for admitting liquid from the Well thereinto', a reciprocable eductlon pipe in communication with said displacement chamber and arranged to open and close said valve in its reciprocation, a source of pneumatic pressure, valve means carried by said eduction pipe for establishing communication between the source of pneumatic pressure and said displacement chamber, a seal dividing said eduction pipe into upper and lower sections, ports above and below said seal adapted to be opened and thereby to permit the bypass flow of liquid from the lower to the upper section of the eduction pipe when it is reciprocated to close the valve admitting liquid to the displacement chamber, and closed to prevent flow of liquid from the lower section of the eduction pipe to the upper when such valve is' open, whereby a predetermined maximum quantity of liquid is initially' confined below said partition in the eduction pipe .and subsequently is expelled to the surface of the well under the inuence of pneumatic pressure applied from the source in the reciprocation of the eduction pipe. .5.' A deep well pump comprising a displacement chamber adapted to extend into the liquid in a welll means for admitting gas under pressure to said displacement chamber during periods when said displacement chamber is not in communication with the liquid in the Well, an eduction pipe communicating with said dis-l placement chamber, means for reciprocating said eduction pipe, a valve actuated by the eduction pipe in`its reciprocation for controlling the inlet of liquid from the well to said displacement chamber, a seal dividing the eduction pipe into upper and lower sections, ports in said eduction pipe above and below said seal, means adapted to place said ports in communication and valve means carried by said eduction pipe cooperat- 'ing with said communication means to establish a bypass around said seal when the eduction pipe is reciprocated to actuate said inlet valve and cut-off communication with the well, thereby to permit the discharge of liquid from said displacement chamber under pressure of gas admitted thereto, said valve means serving to close off communication between the upper and lower sections of the eduction pipe when communication between the well and the displacement chamber is reestablished by opening of the inlet valve, whereby only suicient liquid is admitted to the pump as may be expelled in a slug of predetermined maximum weight.

6. A pump for delivering successive and substantially uniform slugs of liquid to the surface of a well comprising a displacement chamber adapted to extend into the liquid of a well, a reciprocable eduction pipe extending into said displacement chamber, a sealing partition in said eduction pipe dividing it into upper and lower sections, a source of iiuid pressure, inlet valve means carried by said eduction pipe for admitting fluid under pressure periodically to said displacement chamber, ports in said eduction pipe above and below the said partition means cooperating with said ports to form a passageway adapted to by-pass liquid from said displacement chamber around said partition to the upper section of the eduction pipe while pressure is applied to the liquid therein from said source, means acting to close said passage-way upon further reciprocation of the eductionpipe to prevent passage of liquid around said partition during periods when iluid under pressure is not admitted to said displacement chamber and valve means actuated by reciprocation of the eduction pipe to admit liquid from the well into the displacement chamber during periods when the iiuid pressure is cut off therefrom and to cut ofi the displacement chamber from communication with the well liquid during periods when iluid pressure from said source is admitted to said displacement chamber vwhereby said displacement chamber will be alternately filled and emptied but the amount of liquid entering the pump from the well will be limited by said partition so that successive slugs of convenient weight will be formed to be discharged tnrough the eduction pipe around said partition to the zirface of the well when the pump is in opera- 7. A deep well pump comprising a tube string, a displacement chamber at the end of the tube string adapted to extend into the liquid in a well, a reciprocable eduction pipe carrying a foot valve at its endto establish communication periodically between the displacement chamber and the well, said eduction pipe above its lower end constituting a hollow, piston-type valve in communication with the displacement chamber, a seal dividing said piston-type valve into upper and lower sections, ports above and below said seal, means in the wall of said tube string adapted to register with said ports and place them in communication when placed in registry by movement of the eduction pipe and foot valve in a direction to cut oi communication with the well and adapted to close said ports from communication when the eduction pipe is in position to open the foot valve, whereby when communication with the well is established liquid cannot rise in the tubing above the level of such seal, and meansadapted to admit gas under pressure to the displacement chamber when cut off from communication with the well, whereby liquid in the tubing subsequently will be discharged to the surface of the well as a slug of definite, maximum weight.

8. A pump for delivering successive and substantially uniform slugs of liquid to the surface of a well by pneumatic pressure comprising a tube string, a displacement chamber carried by said tube string and adapted to extend into the liquid of the well, a valved inlet in said displacement chamber for intermittently admitting well liquid thereto, an eduction pipe reciprocable within said tube string and communicating with said chamber at its lower end, a seal within said eduction pipe dividing., it into upper and lower compartments, a source of pneumatic pressure, valve means actuated by said eduction pipe for alternately connecting iirst the displacement chamber and then the upper compartment of said eduction pipe with the source of pneumatic pressure, a by-pass connecting the upper and lower compartments of the eduction pipe around said seal and means actuated by reciprocation of the eduction pipe to close said by-pass when the source of pneumatic pressure is connected to the upper part oi the eduction pipe, whereby rise of the well liquid above said seal is prevented when said displacement chamber is cut oi from communication with said source of pneumatic pressure but passage of the well fluid around the seal is permitted when said displacement chamber is connected with said source of pneumatic pressure to discharge the contents of the chamber into the upper compartment of the eduction pipe.

ROY L. CHENAULT.

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