US2589671A - Closed fluid-operated free-pump system with three parallel tubings - Google Patents

Description

March 18, 1952 c, J, COBERLY CLOSED FLUID-OPERATED FREE-PUMP SYSTEM WITH THREE PARALLEL TUBINGS 2 SHEETS-SHEET 1 Filed May 16, 1949 LI IML' March 18, 1952 c. J. COBERLY CLOSED FLUID-OPERATED FREE-PUMP SYSTEM WITH THREE PARALLEL TUBING-S 2 SHEETS-SHEET 2 Filed May 16, 1949 [VVE/VTOPJ (2425/1/05 d 6055? Patented Mar. 18, 1952 UNITED STATES assasn CLOSED FLUID-OPi'sIItATED FREE-PUMP SYS- TEM WITH THREE PARALLEL TUBINGS Clarence J. Coberly,:Los Angeles, Calif., assignor, by mesne assignments, to Dresser Equipment grliliiipany, Cleveland, Ohio, a corporation of Application May 16, 1949, Serial No. 93,483

, 32 Claims. 1

' My invention relates in general to tubing systems 'for fluid-operated well pumps and, more particularly, .to a closed tubing system for a fluid- 5; operated well pump of the so-called free" type.

Reference is hereby made to my copending applications Serial No. 93,482, filed May 16,1949, Serial No. 93,484, filed May 16, 1949, and Serial No. 93,481, filed May 16, 1949.

It is conventional in the oil industry to employ a well pumping apparatus which includes a free fluid-operated pump, such a pump being movable into and out of the well through a tubing set in the well and being adapted to assume an operat-: ing position at the lower end of such a tubing. 51

Examples of such fluid-operated, free-pump systems are disclosed in my Patents Nos. 2,230,830,

grantedFebruary 4, 1941, and 2,338,903, granted foregoing character, the spent operating fluid discharged by the motor section of the pump is January 11, 1944'.

. In conventional fluid-operated, free-pump systems,. such as those disclosed in my aforemen-l tio'ned patents, two tubings are employed, one for I are intermixed and conveyed upwardly together through the production tubing. Since the operconveying operating fluid downwardly in the wellf to the pump and the other for conveying fluid produced by the well upwardly therein from the pump to'the surface, the two tubings being re-' ferred to hereinafter as the supply and producf tion tubings, respectively. In such conventional systems, the pump is movable into its operating ous provision of such fresh operating fluid reposition through the supply tubing. The supply and production tubings are interconnected at. their lower ends in fluid communication with'cgy each other and with the well so that the pump-,-;. may receive operating fluid from the supply tubing and well fluid fromthe well and so that it may discharge well fluid into the production tubing as production fluid.

In installing such a free pump in the well,fi t is moved downwardly through the supply tubing into its operating position at the lower end ther'eof either by the action of gravity or by the appli cation of fluid pressure to the upper endof the pump. After the pump has been installed in its operating position, operating fluid, which is M usually clean crude oil, is delivered to the motor section of the pump under relatively high pressure through the supply tubing. As is well known in the art, such operating fluid is alternately- 5 directed by'a' suitable valve mechanism in the motor section of the pump to opposite ends of a 3,

motor piston which is coupled to a pump piston in the pump' section of the device, fluid from the o well being admitted to th pump section by'a suitable-valve mechanism therein. Such alterthe ends of the motor piston produces reciprocation of the motor and pump pistons with the result that the pump piston pumps fluid produced by the well into the production tubing, the latter conveying the production fluid upwardly therein to the surface. When removal of the pump from the well is desired for any reason, as for service or repair, fluid pressure is applied to the lower end of the pump to move it upwardly out of its operating position and through the supply tubing to the surface This is accom plished conventionally by reversing the flow through the system so that operating fluid flows downwardly in the production tubing tothe lower end of the pump and acts on the pump to move it upwardly through the supply tubing to the surface.

In a conventional free-pump system of the delivered to the production tubing so that the spent operating fluid and the production fluid ating fluiddelivered to the pump through the supply tubing must be clean, in order to prevent abrasion and corrosion of the moving parts of the pump, fresh operating fluid must be supplied to the system continuously. This continuquires considerable surface equipment, normally inthe form of settling tanks or filters, which .is expensive to install and operate. Also, in the particular arrangement hereinbefore mentioned wherein the pump is disposed. in the supply tubing, the flow reversal necessary to remove the pump from the well may carry any sand or other foreign matter present in the production fluid into the supply tubing with the result that such foreign matter may enter the motor section of the pump upon resumption of operation after" reinstallation with the attendant possibility of damage to the pump.

In view of the foregoing, it is a primary object of this invention to provide a closed system for thefluid-operated, free pump which includes a third tubing separate from the supply and pro:

duction tubings for returning the spent operating fluid tothe surface independently'of the well fluid, the tubing for returning the spent operating fluid being referred to hereinafter as the: return tubing. With such ,a closed system, the

" spent operating fluid is separately conveyed back to the surface for storage and re-use-to actuate.

hating application of operating fluid pressure to pi 5 the fluid-operated pump so that'there is very little loss of operating fluid from thesystern and,

consequently, the surface equipment necessary to supply fresh operating fluid to the system needs have only a relatively small capacity and can be relatively cheap and economical, both as regards initial cost and operating costs. Also, he reversed flow necessary to move the pump upwardly to the surface during removal of the pump may take place through the return tubing to avoid carrying sand and other foreign matter into that portion of the system reserved for the operating fluid, which is an important feature. As will be pointed out in more detail hereinafter, further objects of the invention reside in certain modifications of the pump and in the tubing arrangements employed to provide such a closed system.

Considering the invention more specifically,

an object thereof is to provide a closed system for a fluid-operated, free pump comprising supply, return and production tubings which are set in the well and. one of which is adapted to receive the pump and to provide an operating position for the pump at its lower end, the supply, return and production tubings respectively being adapted to convey operating fluid for actuating the pump downwardly into the well to the pump, spent operating fluid discharged by the pump upwardly in the well from the pump to the surface, and production fluid discharged by the pump upwardly in the well from the pump to the surface.

Another object is to provide such a closed system wherein the three tubings are in erconnected at their lower ends in fluid communication with each other and with the well so that the pump may, when in its operating position, re-

ceive operating fluid for its actuation from the supply tubing through an intake, discharge spent operating fluid into the return tubing through an exhaust, receive well fluid from the well through an inlet, and discharge well fluid into the production tubing through an outlet.

Another object is to provide a closed system having means whereby a downward flow of fluid through one of the tubings, other than the tubing in which the pump is disposed, may be applied to the lower end of the pump to move it upwardly out of its operating position and through the tubing in which it is disposed to the surface whenever removal of the pump from the well is desired.

Another object is to provide a closed system which includes a tubular pump receiver disposed at the lower end of and in alignment with the tubing through which the pump is movable, the pump receiver being, in effect, an extension of suchtubing and providing the aforementioned operating position for the pump. A related object is to provide a pump receiver having a seat at its lower end for the the pump being seated on such seat when it is in its operating position.

Another object is to provide a pump receiver 7 having passages which place the interior thereduction tubing, respectively, when the pump is disposed in the pump receiverand seated on the pump seat.

Another object is to provide sealing means for normally preventing direct flow between the tubings and the well by way of the pump re ceiver when the pump is in its operating position so that operating fluid may flow only from the supply tubing through the motor section of the pump to the return tubing and so that well fluid may flow only from the well through the pump section of the pump to the production tubing. More specifically, an object in this connection is to provide a sealing means which, when the pump is in its operating position, places the supply tubing in fluid communication with only the intake of the pump, the return tubing in fluid communication with only the exhaust of the pump, the well in fluid communication with only the inlet of the pump and the production tubing in fluid communication with only the outlet of the pump.

Another object is to provide a system where in the aforementioned sealing means comprises annular sealing elements which are carried by the pump adjacent various of the ports, such as the intake, etc., therein and which are engageable with the inner wall of the pump receiver to prevent direct flow between the tubings.

Another object is to provide passage means communicating at one end with one of the tubings, other than the tubing aligned with the pump receiver, and at its other end with a chamber in the pump receiver between the pump seat and the pump for applying a downward flow of fluid through such tubing to the lower end of the pump to move it upwardly out of the pump receiver and to the surface.

Another object is to provide a sealing device for normally preventing fluid flow between two of the tubings by way of the aforementioned passage means and the pump receiver when the pump is in its operating position. Other objects in this connection are to provide a system wherein the aforementioned sealing device is a spring-loaded valve in the passage means and a system wherein the sealing device is an annular sealing element adapted to be disposed between the pump and the pump receiver.

Another object is to provide a system wherein the tubing with which the aforementioned passage means communicates is the return tubing so that the pmnp may be moved upwardly to the surface by a downward flow of clean fluid through the return tubing to prevent introducing sand and other abrasive matter into the pump receiver.

Still another object is to provide a closed system wherein the pump is movable into its operating position in the pump receiver through the 1 supply tubing and wherein the pump is movable out the production tubing, which is an important feature.

Another object is to minimize the power required to overcome friction between the production fluid moving upwardly through the production tubing and the wall of the production tubing by employing a production tubing having a large internal diameter. This feature is particularly important under well conditions such that a motor and/or pump sections of maximum capacity, which is an important feature.

Another object is to facilitate paraihn control in such a closed system by limiting contact of the production fluid to the production tubing, i. el, by disposing the supply and return tubings without the production tubing.

An important object of the invention is to provide a closed system wherein the supply, return and production tubings are set in the well side-by-side so that the downward flow of operating fluid and the upward flows of spent operating fluid and production fluid contact only their respective tubings.

The foregoing objects and advantages of the present invention, together with other objects and advantages thereof which will become apparent, may be attained through the employment of the exemplary embodiments of the invention which are illustrated in the accompanying drawings and which are described in detail hereinafter. Referring to the drawings:

' Fig. 1 is a utility view of a closed, fluid-operatied. free-pump system which embodies the in vention; n

Figs. 2 and 3 are enlarged, horizontal sectional views respectively taken along the broken lines 2-2 and 3 -3 of Fig. 1;

Figs. 4 and 5 are enlarged, vertical sectional views respectively taken along the irregular broken lines 4-4 and 55 of Figs. 2 and'? Fig.

Bbeing a downward continuation of Fig. 4;

Fig. 6 is a utility view ofanother embodiment of the invention; Figs. '7 and 8 are enlarged, horizontal sectional views respectively taken along the broken lines 1-! and 8-8 of Fig. 6; l

Figs. 9 and 10 are enlarged, vertical sectional views respectively taken along the. broken lines 99 and I -H] of Figs. 7 and 8; and,

Fig. 11 is an enlarged, vertical sectional view taken along the broken line' II--II of Fig. 7.

Referring particularly to Fig. l of' the drawiings, the numeral I designates a well casing which is set in an oil well with its lower end open to an oil producing formation adjacent the well as is well known in the art, the casing being provided with a casing head I6 at its upper end. Set in the well within the casing I5 and con: nected to the casing head I6 is a closed tubing system which comprises supply, return and production tubings set side-by-side andrespectively designated by the numerals I I, I8 and I9. As will be discussed in more detail hereinafter, the supply, return and production tubings I'I, I8 and I9 are interconnected at their lower ends in fluid communication with each other and with the well by a tubular pump receiver 26 which is aligned with and which, in effect, forms a downward extension of one of the tubings, the pump receiver being aligned with the supply tubing I! in theparticular embodiment presently under consideration. The pump receiver12il provides an operating position for a fluid-operated, free pump 2I- which is movable downwardly through the supply tubing I! into its operating position in the pump receiver, the internal diameter of in more detail hereinafter. the pump head 29 are supply, return and producthe pump receiver being substantially equal to that of the supply tubing. As will be discussed in more detail hereinafter, the supply tubing I! is adapted to convey operating fluid, such as .clean crude oil, under pressure downwardly in the well from the surface to the pump 2| to actuate the pump, and the return tubingI8- is adapted to receive spent operating fluid discharged by the pump and to convey the spent operating fluid upwardly in the well to the surface. The pump 2| is adapted to receive well fluid from the well and to discharge it into the production tubing I9 as production fluid, the production tubing conveying the production fluid upwardly inthe well to the surface.

In the particular construction illustrated, the lower ends of the tubings II, I8 and I9, and the pump receiver 20, are enclosed by a gas anchor 22 having a perforated barrel 23 which is closed fatits upper and lower ends by heads 24 and 25, respectively, the upper head having suitable openings therethrough for the tubings. The gas anfchor 22 is secured to the pump receiver by a "bolt 26 connecting the lower head to the-pump receiver. V ;;The supply, return and production tubings I], I8 and I9 are connected at their upper 'ends' to a pump head 29 having valve means (not shown) therein which is operable from the surface by a handle 30 to direct flows of fluid through the tubings in the proper manner as will be, discussed Also connected ;to

tion lines 3I, 32 and 33 which, during operation of the pump 2I, are adapted to be connected in fluid communication with the supply, return and production tubings Ii, I8 and I9, respectively, by

the valve means in the pump head. The supply line 3I leads to a suitablesource (not shown) of operating fluid under pressure, which source may be a conventional triplex pump having its intake connected to a suitable reservoir." The return line 32 leads to the reservoir, and the production "line 33 leads to a suitable point of disposal or storage for the production fluid. As disclosed in my aforementioned Patent No. 2,338,903, the pump head 29 may also include a suitable pump catcher (not shown) for the pump 2I, the latter having at its upper end a tapered head 35 which is receivable by the pump catcher during removal of the pump from the well.

Referring now to Figs. land 5 of the drawings,

the pump receiver 2i! is, as previously indicated,

aligned with and connected to the lower end of the supply tubing If, the pump receiver having at its upper end a sleeve which is threaded onto the lower end of the supply tubing. The lower end of the sleeve 49 is threaded into the upper end of a major bore 4! in an upper fitting 42 which forms part of the pump receiver .20, a

I sleeve 43 being threaded into the lower end of the major bore 4|. The lower end of the sleeve 43 is threaded into the upper end of a major bore 44 in a lower fitting 45 of the pump receiver 20, an inlet sleeve 46 which communicates at its lower end with the well through the perforated gas anchor barrel 23, being threaded into the lower end of the major bore 44.

The upper fitting 42. of the pump receiver 20 ispi ovided with a minorbore ifl into which the lower end of the return tubing I8 is threaded,

the minor bore 49 communicating withthe major bore 4,!) in the fitting. .42 through a lateral pas: sagev 5c in this fitting and through a registering pcrtfii in a liner 52 which is'disposed in the major bore 4|. The lower fitting 45 of the pump receiver 20 is provided with a minor bore 54 into which the lower end of the production tubing I9 is threaded, the minor bore 54 communicatin with the major bore 44 in the fitting 45 through a lateral passage 55. Thus, with this construc tion, the pump receiver 20 interconnects the lower ends of the supply, return and production tubings ll, 18 and iii in fluid communication with each other and with the well.

The upper fitting 42 of the pump receiver 2%! is provided with a passage means 58 for applying a downward flow of fluid through the return tubing It to the lower end of the pump 21 to move the pump upwardly out of the pump receiver 2i) and through the supply tubing H to the surface when removal of the pump is desired for any reason, this passage means comprising a longitudinal passage 59 which communicates at its upper end with the minor bore 39 in the fitting 62 and which communicates at its lower end with a chamber 60 in this fitting. The passage means 58 also includes a lateral passage 5| which connects the chamber (iii to the major bore 4! in the fitting 42 through an annular groove 62 in this fitting. Disposed in the chamber 60 is a spring-loaded valve 63, which prevents flow of fluid from the return tubing I8 into the interior of the pump receiver 26 during normal operation of the pump 2|, and which is adapted to open to permit such flow in response to'a downward flow of fiuid through the return tubing l8 during removal of the pump from the well, as will be discussed in more detail hereinafter.

The minor bore 54 in the lower fitting 45 of the pump receiver 28 contains a standing valve 56 which. is adapted to prevent downward flow of fiuid' from the production tubing l9 into the interior of the pump receiver but which is adapted to open to permit upward flow of production fluid discharged by the pump 2| into the production tubing. The valve 65 is provided with spring fingers 51 which engage shoulders 68 in the minor bore 54 to hold the valve in its operating position, and includes an inside spear fitting 69- which is adapted to be engaged by a suitable tool lowered into the well through the production tubing [9 when removal of the valve is desired, as is well known in the art. 7

Disposed in the lower end of the major bore 44 in the lower fitting 45 of the pump receiver and extending downwardly into the inlet sleeve 45 is an inlet fitting 12 for the pump 2|, the latter having an inlet which is adapted to receive well fluid from the well through the inlet fitting when the pump is in its operating position, as will be discussed in more detail hereinafter. As is well known in the art, the inlet fitting 12 is preferably provided with a check valve (not shown) therein which permits upward flow of well fluid into the interior of the pump receiver 20, but which prevents downward flow of fluid out of the pump receiver into the well. The inlet fitting i2 is seated on an annular insert 13 which is disposed in the major bore 44 in the lower fitting 45 and which is seated on a shoulder T4 therein.

The inlet fitting 12 also serves as a seat for the pump 2|, the latter being in its operating position when it is disposed in the pump receiver 20 and seated on the pump seat provided by the inlet fitting; The pump 2| is adapted to seat on the inlet fitting 12 automatically when it is moved downwardly through the supply tubing i! into the pump receiver 20 so that it automat- 8 ically assumes its operating position upon engaging the inlet fitting.

Except for certain modifications required to adapt it to the closed tubing system of the invention, the fluid-operated free pump 2| may be of conventional design and will not be described in detail. In general, the pump 2! includes a motor section and a pump section below the motor section, the motor and pump sections respectively including coupled motor and pump pistons (not shown). The motor section of the pump 2| is actuable by operating fluid under pressure delivered thereto by the supply tubing 11, the operating fluid under pressure being adapted to enter the motor section of the pump through ports which serve as an intake 18 for the pump and which are in fluid communication with the supply tubing when the pump is in its operating position. The ports of the intake 18 are formed in an intake fitting 79 which provides the aforementioned tapered head 35 and which is connected to the upper end of a tubular rod 80 extending upwardly from the motor section of the pump 2|, the rod being adapted to cohvey the operating fluid under pressure from the intake to the motor section of the pump.

After the operating fluid admitted to the motor section of the pump 2! through the intake 18 has performed its function, it is discharged from the motor section through ports forming an exhaust 8| for the pump. When the pump 2| is in its operating position, the exhaust 8| communicates with an annular space 82 between the pump and the liner 52 in the major bore 41 in the upper fitting 42, the annular space 82 communicating with the return tubing it through the port 5i in the liner, the lateral passage 50 in the fitting 42 and the minor bore 49 in this fitting. Thus, the operating fluid under pressure in the supply tubing I'I flows through the motor section of the pump 2| to actuate it and is discharged into the return tubing I8 as spent operating fluid.

In order to prevent direct flow of operating fluid between the supply and return tubings l1 and I8 by way of the pump receiver 28, I provide sealing means comprising an annular sealing element 86 which is carried by the pump 2| intermediate the intake 78 and the exhaust 8| and which is adapted to engage the liner 52 above the port 5| therein when the pump is in its operating position. The annular sealing element 86 is preferably of the O-ring type and is formed of oil-resistant rubber, or other suitable material. The pump 2! carries another, similar annular sealing element 81 below the exhaust 8|, this sealing element being adapted to engage the liner 52 between the port 5! therein and the groove 82 of the passage means 56 when the pump is in its operating position. Thus, the annular sealing elements 86 and 81 isolate the intake 78 and'the exhaust 8! when the pump 2| is in its operating position so that the intake may communicate only with the supply tubing l1 and so that the exhaust may communicate only with the return tubing 18.

As previously indicated, the pump section of the pump 2! is provided with an inlet (not shown specifically) at its lower end. through which well fluid is adapted to enter the pump section by way of the inlet fitting 72. The pump section of the pump is also provided with ports forming an outlet 88 for production fluid discharged'by the pump section, the outlet communicating with an annular space 89' between the pump and the sleeve 43 connecting the upper and lower fittings 42 and 45 of the pump receiver 20. The annular space 89 extends downwardly- .production fluid discharged by the pump section of the pump 2| through the outlet 88 flows.

through the annular space 89 and the annular chamber 9| into the lateral passage 55 in the lower fitting 45 and thence upwardly through theminor bore 54 in this fitting into the production tubing I9.

.- It will be noted that the annular sealing element 81 is disposed between the exhaust 8| and the outlet 88 so that it prevents flow between the return and production tubings l8 and' I9 when-the pump is in its operating position. Also,

since the pump 2| is seated onthe inlet fitting 12 when in its operating position, the pump seat provided by the inlet fitting serves to prevent direct flow between the well and the production tubing l9. Flow between the return and produc-' tion tubings l8 and I9 by way of the passage.

means 58 is prevented by the spring-loaded valve 63 when the pump is in operation, as hereinbefore indicated. 1

Considering the operation of the embodiment of the invention hereinbefore described, it will be assumed that the pump 2| is in operation to pump fluid from the well upwardly through the production tubing l9 to the surface. Under such conditions, the pump 2| is in its operating position in the pump receiver 20 wherein it is: seated on the inlet fitting 12 and the aforemen-p tioned valve means in-the pump hea-d29 respectively connects the supply, return'and pro-' duction tubings l7, l8 and 19 to the supply, re-

turn and production lines 3|, 32 and 33. Thus,

operating fluid under pressure is conveyeddownwardly to the pump 2 I through the supply tubing I1 .and enters the motor section of the pump throughthe intake 18 to actuate the pump, spent operating fluid being discharged-into the return tubing I8 through the-exhaust-8l and being-conveyed upwardly in the well to the surface by'the return tubing. The well fluid entering the pump section of the pump 2| through its inlet is dis-- chargedintotheproductiontubing l9 throughgm the outlet 88 and is conveyed upwardly: in the welltothe-surface asproduction fluid. Itwill be. apparent that, with this construction, the

spent. operating fluid is returned to the surface separately from the production fluidso that it maybe .re-used to actuate the pump-2|, which is ajprimary feature .of the invention.

In the event that removal of the pump 2 l'from thewell is necessary .in-order to service or repair the pump, or for any other reason, the operator sets the handle 30 controlling the valve means,

in the pumphead 29 ina position such that the;

valve means connects the supply line 3| to the return tubing =-|8 .so that operating fluid under;

pressure ,flows. downwardly into the'well through.- the-return-tubing. Preferably, the valve means also connects-the supply tubing H to the return line -32- under such conditions, and prevents .fluid communication between the productiontubing';

l9 andtheproduction line 33. -Alternatively,'.

fluid flow through-the production tubing |9-and--- the, production line- 33 may be'prevented by,"

ee n 3* :Val 9, in? h -erq uetien; li e at:

tubing I! in a substantially fluid-tight though it will be understood that this function is-- preferably performed by the valve means in the pump head 29.

Under the conditions outlined in the preceding,

above the spring-loaded valve 63 is insuflicient to open the valve. The pressure of the operat-,

ing fluid entering the annular chamber 9| in the foregoing manner is applied to an annular area 95 atthe lower end of the pump 2| so as to unseat the pump from the inlet fitting I2 and is then applied tothe entire area of the pump so as to moveit upwardly in the pump receiver20, upward fiowof the operating fluid applied to the lower end of the pump in this manner past the pu p being prevented by the annular sealing elements iifi and 81 which engage the liner 52. Afterthe pump 2| has moved upwardly in the pump receiver 29 a distance such that the annular sealing elements 86 and 81 disengagethe liner 52, upward flow of operating fluid past the pumpis preventedby packing devices 96 and 91 which are carried by the rod and which are adapted to engage the inner wall of the supply manner. the portions of thepump-2l which carry the annular sealing elements ;86 and 81 preferably being of smaller diameter than the internal diameter of the supply tubing so as to prevent damage to these sealingfelements during movement of the pump through 1 the supply tubing. After the pump has cleared-the port 5| in the liner 52, the downward flow of operating fluid through the return tubing I8 is applied to the lower end of the pump to move it upwardly directly through the lateral passage 50 and the port 5|. Thus, the'operating fluid under pressure flowsth'rough the passagemeans 58 to unseat the pump 2| and to move it upwardly in.

the, pump receiver 20 a sufficient distance to clear; the .port 5|. Thereafter, the downward flowof' operating fiuidunder pressure through the return tubing l8 enters the pump receiver 29 ing. the aforementioned valve 94, or by means of" the valve means in the pump head 29. It

willmbe-noted that, since the standing valve 66 prevents downward flow of production fluid out of the production tubing l9 and into the pump I receiver, none of the production fluid can enter 'the pump receiver during the pump-removal operation-which is an important feature since it prevents sand and other foreign matters which may Joe; in the production fluid from entering t awin e v r- It will be noted that, under the conditions hereinbefore outlined, the operating fluid in the supply tubing I1 above the pump 2| is returned 7 to the reservoir through the return line 32 during placed in fluid communication with the supply line 3I and the return tubing I8 is placed in communication with the return line 32. Thus, the operating fluid under pressure entering the system through the supply line 3| acts on the upper end of the pump 2I to move it downwardly through the supply tubing I1 and into its operat ing position in the'pump receiver wherein it is seated on the inlet fitting, I2, the operating fluid previously introduced below the pump during the pump-removal operation being displaced upwardly through the return tubing I8 and into the return line 32 leading to the reservoir on the surface. During the operation of installing the pump, the valve 94, or the valve means in the pump head 29, preferably prevents flow through the production tubing I9 and production line 33 so that all of the fluid employed during the pump-removal operation is returned to the reservoir during reinstallation of the pump. However, it will be understood that if the operating fluid in the supply tubing has become contaminated prior to reinstallation of the pump 2| for any reason, returning such contaminated-operating fluid to the reservoir may be avoided by preventing fluid flow through the return tubing I8 and by permitting fluid flow through the production tubing I9.

As will be apparent, one advantage of the embodiment hereinbefore discussed is that it is possible to remove and reinstall the pump 2| with substantially no loss of operating fluid from the system, the production tubing I9 being isolated from that portion of the system reserved for the operating fluid during both the pump-removal operation and the pump-installation operation.

It will also be noted that since the production fluid comes in contact only with the production tubing I9, because of the fact that the supply and return tubings I 1 and I8 are located without the production tubing, paraffin control is'simplified and damage to the system by the action of any corrosive substances which may be present in the production fluid is minimized, such corrosion damage being restricted to the production tubing.

Another advantage is that the production fluid flowing through the annular chamber 9| during operation of the pump 2I continuously washes away any sand deposits tending to form at the junction of the pump and the inlet fitting I2 to prevent obstructing the pump seat provided by this fitting.

nected to the casing head H6 is a closed tubing system of the invention which comprises supply, return and production tubings set side-by-side and respectively identified by the numerals H1, H8, and 9. As will be discussed in more detail hereinafter, the tubings H7, H8 and II9 are interconnected at their lower ends in fluid communication with each other and with the well by a tubular pump receiver I20 which is aligned.

with and which, in effect, forms a downward extension of the production tubing I9. The pump receiver I20 provides an operating position for a fluid-operated, free pump I2I which is movable downwardly through the production tubing II9 into its operating position in the pump receiver, the internal diameter of the pump receiver being substantially equal to that of the production tubing. As in the previously discussed embodiment, the supply tubing H1 is adapted to convey operating fluid under pressure downwardly in the well to the pump I2I to actuate the pump, and the return tubing H8 is adapted to convey spent operating fluid discharged by the pump upwardly in the well. The pump I 2| is adapted to receive well fluid from the well and to discharge it into the production tubing II9 as production fluid, the production Q tubing then conveying the production fluid upwardly to the surface.

As in the previously described embodiment, the lower ends of the tubings I I! to I I 9 and the pump receiver I20 may be enclosed by a gas anchor I22 having a perforated-barrel I23 which is closed at its upper and lower ends by heads I24 and I25,

dle I30 to direct flows of fluid through the tub ings in the proper manner. Supply, return and production lines I3I, I32 and I33 are also connected to the pump head I29 and are adapted to be connected in fluid communication with the supply, return and production tubings H1, H8

and H9, respectively, by the valve means in the pump head during operation of the pump I2I.

As in the preceding embodiment, the supply line I3I leads to a suitable source of operating fluid under pressure, the return line I32 leads to a reservoir for the source and the production line I33 leads to a suitable point of disposal for the production fluid.

Referring now to Figs. 9 and 10 of the drawqings, the pump receiver I20 is, as previously in- Turning now to the embodiment of the inven 'dicated, aligned with and connected to the lower end of the production tubing II9, the pump receiver having at its upper end a sleeve I40 which is threaded onto the lower end of the production tubing. For a reason which will be pointed out hereinafter, the internal diameter of the sleeve I49 is slightly greater than that of the produc tion tubing I I9. The lower end of the sleeve I40 is threaded into the upperend of a major bore MI in an upper fitting I42 which forms part of the pump receiver I20, a sleeve I43 being threaded into the lower end of this major bore. The lower end of the sleeve I43 is threaded into the upper end of a major bore I44 in a lower fitting I45 of the'pump receiver 'I20,an inlet sleeve.

I46 being threaded into the lower end of the spaced laterally from the major bore I4I therein, the lower ends of the supply and return tubings H1 and H8 being threaded into the upper ends of the minor bores I41 and I48, respectively. The minor bore I41 communicates with the interior of the tubular pump receiver. I29 through a lateral passage I49 in the upperfitting I42 and through a port I50 in a liner II which is pressed into the major bore MI in the upper fitting. The minor bore I48 communicates with the interior of the pump receiver I through a lateral passage I52 in the upper fitting I42 and through a port I53 in the liner I 5I. As best shown in Fig. 11 of the drawings, the upper fitting I 42 is also provided with a passage I54 therethrough which communicates with the interior of the pump receiver above the lateral passage I49 and the port I50 and which communicates with the interior of the pump receiver below the lateral passage I52 and the 'port I53. As will be discussed in more detail hereinafter, the passage I54 is adapted to convey production fluid discharged by the pump I2I upwardly through the upper fitting I42 and into the production tubing II 9 above the body of the pump I2I. It will be apparent that, with this construction, the pump receiver I20 interconnects the lower ends of the supply, return and production tubings H1, H8 and H9 in fluid communication with each other and with the well.

"The embodiment presently under consideration is provided with a passage means I58 for applying a downward flow of fluid through the return tubing II8 to the lower end of the pump I2I to unseat the pump and move it upwardly out of the pump receiver I20 when removal of the pump is desired for any reason, this passage means including a tube I59 which is threaded at its u per end into the lower end of a bore I60 communicating with the minor bore I48 in the upper fitting I42. The lower end of the tube I59 is threaded into the upper endof a bore IBI ad acent the major bore I44 in the lower fitting I45. the bore IBI communicating with an annular chamber I62 within the pump receiver I 20 at the lower end of the pump I2I through lateral passages I53 and an annular groove. I64. In actual practice, instead of forming the bore I 6| directly in the lower fitting I45, I' prefer to form this bore and the lateral passages I63 and the groove I 64 in an insert I65 which is disposed in a bore I66 formed in the lower fitting proper, the tube I59 being threadedly connected to this insert and the insert carrying sealing rings I61 above andbelow-the annular groove I64. 4 This construction facilitates assembling thenpper. and lower fittings I42 and I54, the intermediate sleeve I 43 and the tube I59 since the insert I65 may slide in the bore I66 while the intermediate sleeve I43 is being threaded intov theupper and lower fittings.

Disposed in 'the lower end of the major bore I44 in the lower fitting I45 of the pump receiver I20f'an'd extending downwardly into the inlet sleeve I 46', is an inlet fitting I12 for the pump I2I, thelatter having an inlet which is adapted to'receive well .fluid. from the well.v through the inletfittingwhen the pump is in its operating positipiiaswill be discussed in more detail here- White-514 isr k wn. i i e, the inlet fitting I12 is preferably provided with a checkvalve (not shown) therein which permits upward flow of well fluid into' the interior of the pump receiver I20, but which prevents downward flow of fluid out of the pump receiver'into the well..,'

The inlet fitting I12 is seated on an annular insert I13 which is disposed in the major bore I44 in the lower fitting I45 and which is-seated on a shoulder I14 therein. i

As in the previously discussed embodiment,

the inlet fitting I12 also serves as a seat for thef pump I2I, the latter being in its operating position when it is disposed in the pump receiver I20 and seated on the pump seat provided by the inlet fitting. The pump I2I is also adapted to seat on the inlet fitting I12 automatically when it is moved downwardly through the production tubing II9 into the pump receiver I20 so that it automatically assumes its operating position.

The pump I2I is substantially identical to the pump 2I and includes a motor section which is actuable by operating fluid under pressure .delivered thereto through the supply tubing II1, the operating fluid under pressure being adapted to enter the motor section of the pump through an intake I18 which comprises an annular groove I19 and registering ports I80, the groove I19 registering with the port I50 in the liner I5I when the pump is in its operating position. After the operating fluid admitted to the motor sec-- tion of the pump I2I through the intake. I58

has actuated the pump, it is discharged from the motor section through ports forming an exhaust IBI for, the pump. When the pump ,I2I is in its operating position, the exhaust I8I communicates with an annular space I82 between the pump and the linear I5I in the major bore MI I48 in this fitting. Thus, the operating fluid under pressure in the supply tubing ,II1 flows through the motor section of the pump I M to actuate it and is discharged into the return tubing I I8 as spent operating fluid.

The embodiment under consideration includes sealing means for preventing direct flow between the supply, return and production tubings I I1,-.

H8 and H9 when the pump I2I is in its operating position, such sealing means comprising, annular sealing elements I85, I86 and I81 carried by the pump. The. annular sealing element I85. is located abovethe intake I18 and serves to separate the supply tubing I H from the produc-.-

tion tubing II9 when the pump is in its operating position. The sealing element I86 isdisposed between the intake I18 and the exhaust IBI and prevents direct flow between the supply tubing H1 and the return tubing II8 when the pump is in its operating position, the sealing element I81 being disposed below the exhaust I8I and, as will be discussed hereinafter, being adapted to prevent mixing of the production fluid and the spent operating fluid. Thus, the annular sealing elements I to I81 isolate the intake I18 and the exhaust I8I when the pump I2I is in its operating position so that the in-" take may communicate only with the supply tubing .I I1. and so thatthe exhaust may communi cate onlywith the return tubing I I8. x

As previously suggested, the pump section of the pump I2I is provided with an inlet (not speciflcally shown) at its lower end through which well fluid is adapted to enter the pump section by way of the inlet fitting I72. The pump section is also provided with ports forming an outlet I88 for production fluid discharged by the pump section, the outlet communicatin with an annular space I89 between the pump and the wall of the tubular pump receiver 128. The previously mentioned passage I54 through the upper i'itting I42 communicates with the annular space I89 and communicates with the interior of the pump receiver above the body of the pump so that production fluid discharged into the'annular space I89 through the outlet IE3 is conveyed upwardly into the upper end of the pump receiver by the passage I54 and then flows upwardly into the production tubing H9. t will be noted that the pump I2I includes a rod I9I which extends upwardly from the motor section of the pump and which carries packing devices I92 and I93, such packing devices being disposed in the enlarged upper sleeve I46 of the pump receiver l2!) when the i in its operating position'so' that the production fluid may flow upwardly past the packing devices into the production tubing I I9,

In order to prevent the production fluid di.,-

charged through the outlet I38 from flowing downwardly into the annular chamber I32 and thence upwardly through the passage means 554! into the return tubing H3 when the pump is in operation, the pump carries an annular sealing element I96 which i disposed below the outlet and which engages a liner I55 in the major bore H4 in the lower fitting I45 when the pump is in its operating position. Thus, th annular sealin element ltd serves to isolate the outlet I88 from the return tubing so that it communicates only with the production tubing when the pump is in it operating position. Also, since the pump is seated on the inlet fitting I32 when in its operating position, the pump seat provided by the inlet fitting serves to prevent direct flow between the and the return tubing IIB.

Considering the operation of the embodiment of the invention disclosed in Figs. 6 to 11 of the drawings, it will be assumed that the pump .I2I is in operation to pump fluid from the well upwardly through the production tubing H9 to the surface. Under such conditions, the pump is in its operating position in the pump receiver I 26 wherein it is seated on the inlet fitting I72, and

the aforementioned valve means in the pump head I29 respectively connects the supply, return and production tubings III, I I8 and IE9 to the supply, return and production lines I3I, I32 and I33. Thus, operating fluid under pressure is carried downwardly to the pump iZI through the supply tubing It! and enters the motor section of the pump through the intake I78 to actuate the pump, spent operating fluid being discharged into the return tubing H8 through the exhaust I3! and being conveyed upwardly in the well to the surface by the return tubing. The well fluid entering the pump section of the pump it: through its ins-t is discharged into the production tubing H9 through the outlet I88 and is conveyed upwardly in the well separately from the spent operating fluid.

In the event that removal of the pump I2I is necessary, the operator sets the handle I39 controlling the valve means in the pump head I29 in a position such that the valve means connects the supply line iii to the return tubing H8 so the. operating fluid under pressure fiOWs downwardly into the well through the return tubing.

Preferably, the valve mean also connects the seated on the inlet fitting I12.

production tubing H9 to the production line I33 under such conditions so that the production fluid above the pump' i2| may enter the production line. The supply tubing I Il may remain connected to the supply line I3I under these conditions. Alternatively, fluid flow through the supply tubing Ii! may be prevented by closing a valve I98 therein, although this function'may be performed by the valve means in the pump head I29.

Under the conditions outlined in the preceding paragraph, operatin fluid under pressure flows downwardly through the return tubing H8 and into the annular chamber I62 at the lower end of the pump I2I by way of the passage means I58 and acts on an annular area I97 at the lower end of the pump so as to unseat the pump from the inlet fitting H2 and then acts on the entire area of the pump so as to move it upwardly in the pump receiver I29, upward flow or the op erating fluid applied to the lower end of the pump in this manner past the pump being prevented by the annular sealing elements I85 to E8? and IE5. After the pump I2I has moved upwardly in the pump receiver I20 a distance such that the annular sealing elements I85 to I8! and I95, disengage the liners I5I and H35. upward flow of operating fluid past the pump is prevented by the packing devices I92 ,andsI93 which, by this time, have moved upwardly out of the enlarged upper sleeve I49 and into the production tubing proper. The packing devices I92 and I93 are adapted to engage the inner wall of the production tubing I I9 in a substantially fluid-tight manner, the portions of the pump which carry the annular sealing elements I85 to I87 and I96 preferably being of smaller diameter than the internal diameter of the production tubing so as to prevent damage to these sealing elements during movement of the pump through the production tubing. Continued downward flow of operating fluid under pressure through the return tubing IIB ultimately results in upward movement of the pump E2I through the production tubing IE9 to the surface so that it may be removed from the production tubing through the pump head I29, the production fluid in the tubing I I9 above the pump being displaced into the production line I33.

in the event that the supply tubing I I1 is connected in fluid communication with the supply line I3I during the pump-removal operation, a downward flow of fluid through the supply tubing occurs to assist in removing the pump once the pump has cleared the port I58 in the liner I5I.

During the foregoing pump-removal operation, flow of the operating fluid employed to remove the pump out of the pump receiver I20 into the well is prevented by the check valve in the inlet fitting I12. a

When reinstallation of the pump I2I, or installation of a replacement pump I2I, is desired, the pump to be installed is inserted into the upper end of the production tubing [I9 through-the pump head I29. The operator then sets the handle I39 controlling the valve means in the pump head in a, position such that the production tubing I I9 is placed in fluid communication with the Supply line I3I. Thus, the operating fluid under pressure entering the system through the supply line 52%| acts on the upper end of the pump to move it downwardly through the production tubing H9 and into its operating position in the pump receiver I29 wherein itis The operating 17 fluid previously introduced below the pump during the pump-removal operation may be displaced upwardly through the return tubing H8, or through both the return tubings H8 and the supply tubing I H. The operating fluid displaced upwardly in this manner may be returned to the reservoir for reuse if the wallsof the production tubing H9 are relatively free from sand or other abrasive material, although it may be desirable to dispose of such displaced operating fluid if abrasive matter is present. In the latter circumstance, it would be necessary to replenish the operating fluid lost from the system with fresh operating fluid.

As in the case of the previously described embodiment, since the production fluid comes in contact only with the production tubing I [9, because of the fact that the supply and return tubings H1 and H8 are located without the production tubing, paraffin control is simplified and damage to the system by the action ofany corrosive substances which may be present in the production fluid is minimized, such corrosion damage being restricted to the production tubing.

It will be noted that in either of the embodiments hereinbefore described, the tubing forthe pump may be of relatively large internal diameter so that a pump of relatively large external diameter may be employed to provide maximum capacity for the motor and/or pump sections of the pump.

An important advantage of the embodiment illustrated in Figs. 6 to 11 of the drawings is that it permits employing a production tubing H9 of relatively large internal diameter so as to minimize frictional losses between the production fluid stream and the production tubing, which is important in wells permitting the use of a pump having a pump section of large-capacity and a motor section of small capacity.

Although I have disclosed exemplary embodiments of the invention for purposes of illustration, it will be understood that various changes, modifications and substitutions may be incorporated in such embodiments without departing from the spirit of the invention.

I claim as my invention:

1. In a closed, fluid-operated, free-pump system for a well, the combination of: a supply tubing set in the well and adapted to convey operating fluid downwardly into the well from the surface; a return tubing set in the well and adapted to convey spent operating fluid upwardlyin' the well to the surface; a production tubing set in the well and adapted to convey fluid produced by the well upwardly therein to the surface; means for interconnecting the lower ends of said tubings in fluid communication with each other and with the well; and a fluid-operated; free pump movable in one of said tubings into an operating position at the lower endthereof; said pump having an intake, an exhaust, an in-i let andan outlet which communicate withsaid supply tubing, said return tubing, the well and said production tubing, respectively, when said pump is in said operating position.

2. In aclosed, fluid-operated, free-pump systtem for a well, the combination of: three tubings set in the well and respectively adapted to convey operating fluid downwardly into the well from the surface, spent operating fluid upwardly; in the well to the surface and fluid produced by theiwell upwardly therein to the surface; means forinterconnecting the lower ends of said tubings in fluid communication with each other and with the 18 well; a pump seat at the lower end of and aligned with one of said tubings; and a fluid-operated, free pump movable in said one tubing into an operating position at the lower end thereof wherein it is seated on said pump seat, said pump having an intake, an exhaust and an outlet which communicate with said tubings, respectively, when said pump is in said operating position, and having an inlet which communicates with the well when said pump is in said operating position.

3. In a closed, fluid-operated, free pump system for a well, the combination of a supply tubing set in the well and adapted to convey operating fluid downwardly into the well from the surface; a return tubing set in the well and adapted to convey spent operating fluid upwardly in the well to the surface; a production tubing set in the well and adapted to convey fluid produced by the well upwardly therein to the surface; a tubular pump receiver at the lower end of and aligned with one of said tubings, said pump re-.' ceiver being connected to the lower endsof said tubings in fluid communication therewith and being in fluid communication with the well; and a fluid-operated, free pump movable in said one tubing and movable into an operating position in said pump receiver, said pump having an intake, an exhaust, an inlet and an outlet which communicate with said supply tubing, said return tubing, the well and said production tubing, respectively, when said pump is in said operating position in said receiver.

4. A closed system as set forth in claim 3 including sealing devices for normally preventing direct flow of fluid between said tubings and the well when said pump is in said operating position. 5. In a closed, fluid-operated, free-pump system for a well, the combinationof: a supply tubing set in the well and adapted to convey operating fluid downwardly into the well from the surface; a return tubing set in the well and adapted to convey spent o'perating fluid upwardly in the well to the surface; a production tubing set in the well and adapted to convey fluid produced by the Well upwardly therein to the surface; a tubular pump receiver connected to the lower ends of said tubings in alignment with one of said tubings, said pump receiver communicating at its upper end with said one tubing and having substantially the same internal diameter as said one tubing, and said pump receiver having passages which provide fluid communication between the others of said tubings andsaid pump receiver and between the well and said pump receiver; a'pump seat carried by said pumppre-i ceiver at the lower end thereof and in alignment therewith; a fluid-operated, free pump movable in said one tubing and movable into an operating position in said pump receiver wherein it is seated on said pump seat, said pump having an intake, an exhaust, an inlet and an outlet which communicate with said supply, tubing,j ,said return'tubing, the well and said production tubing, respectively, when said pump is in said operating position; and sealing devices for normally preventing direct flow of fluid between said tubings and the well by way of said pump receiver when said pump is in said operating position.

6. In a closed, fluid-operated, free-pump system for a well, the'combination of: a supply tubing set in the well and adapted to convey operating fluid downwardly into the well from the surfaces; a return tubing set in the well and adapted to convey spent operating fluid upwardly in the well to the surface; a production tubing set inthe well and adapted .to convey. fluid produced by. the

well upwardly therein to the surface; a tubular pump receiver connected to the lower ends of said tubings in alignment with one of said tubings, said pump receiver communicating at its upper end with said one tubing and having substantially the same internal diameter as said one tubing, and said pump receiver having passages which provide fluid communication between the others of said tubings and said pump receiver and between the well and said pump receiver; a pump seat carried by said pump receiver at the lower end thereof and in alignment therewith; a fluid-operated, free pump movable in said one tubing and movable into an operating position in said pump receiver wherein it is seated on said pump seat, said pump having an intake, an exhaust, an inlet and an outlet which communicate with said supply tubing, said return tubing, the well and said production tubing, respectively, when said, pump is in said operating position; sealing devices for normally preventing direct flow of fluid between said tubings and the well by way of said pump receiver when said pump is in said operating position; a chamber in said pump receiver between said pump seat and said pump; and passage means providing fluid communication between said chamber and one of said other tubings so as to deliver fluid flowing downwardly through said one other tubing to said chamber to move said pump upwardly out of said pump receiver and through said one tubing to the surface.

'7.'In a closed, fluid-operated, free-pump system for a well, the combination of a supply tubing set in the well and adapted to convey operating fluid downwardly into the well from the surface; a return tubing set in the well and adapted to convey'spent operating fluid upwardly in the well to the surface; a production tubing set in the well and adapted to convey fluid produced by the well upwardly therein to the surface; .a tubular pump receiver connected to the lower ends of said tubings in alignment with one of said tubings, said pump receiver communicating at its upper end with said one tubing and having substantially the same internal diameter as said one tubing, and said pump receiver having passages which provide fluid communication between the others of said tubings and said pumpreceiver and between the well and said pumpreceiver; 'a pump seat carried by said pump receiver at the lower end thereof and in alignment therewith; a fluid-operated, free pump movable in said one tubing and movable into an operating 'position in said pump receiver wherein it is seated on said pump seat, said pump having an intake, an exhaust, an inlet and an outlet which communicate with said supply tubing, the welland 'said production tubing, respectively; when said pump is in said operating position; sealing devices for normally preventing direct flow of fluidbetwe'en said tubings and the well by way 'of'said pump receiver when said pump is in said operating position; a chamber in said pump receiver'between said pump seat and said pump; passage means providing fluid communication "between said chamber and one of said other tubings so as to deliver fluid flowing downwardly through said one other tubing to said chamber to move said pump upwardly out of said pump receiver and through said one tubing to the surface; and another sealing device for normally preventing flow of fluid between said passage means and said production tubing.

8. A closed system as set forth in claim 7' wherein said other sealing device comprises a spring-loaded valve in said passage means.

9. A'closed system as set forth in claim '7 wherein said other sealing device comprises an annular sealing element adapted to be disposed between said pump and said pump receiver.

10. In 'a closed, fluid-operated, freepump system :for'a well, the combination of: supply, return and production tubings set in the well and respectively adapted to convey operating fluid downwardly into the well from the surface, spent operating fluid upwardly in the well to the surface and fluid produced by the well upwardly therein to the surface; means for interconnecting the lower ends of said tubings in fluid communication with each other and with the well; a fluid-operated, free pump movable in one of said tubings into an operating position at the lower end thereof, said pump having an intake, an exhaust, an inlet and an outlet which communicate with said supplytubing, said return tubing, the well and said production tubing, respectively, when said pump is in said operating position; means for normally preventing direct flow of fluid between said tubings and the well by way of said interconnecting means when said pump is in said operating position; and passage means communicating with one of the others ofsaid tubings and with said one tubing for applying a downward flow of fluid through said one other tubing to the lower end of said pump to move said pump upwardly from its operating position through said one tubing to the surface. 7

11. A closed system as set forth in claim 10 wherein said supply tubing is said one tubing.

12. A closed system as set forth in claim 10 wherein said production tubing is said one tubing.

13. A closed system as set forth in claim 10 wherein said one other tubing with which said passage means communicates is said return tubi 14. A closed system as set forth in claim 10 wherein said supply and return tubings are without said production tubing 15. A closed system as set forth in claim 10 wherein said one tubing is of larger diameter than at least one of the others of said tubings.

-.16. A closed system as set forth in claim 10 wherein said one tubing is of larger diameter than either of the others of said tubings.

17. A closed system according to claim 1*0 wherein said production tubing is of larger diameter than at least one of the other two tubings;

18. A closed system as defined in claim 10 wherein said production tubing is of larger diameter than either of the other two tubings.

19. A closed system according to claim 10 wherein said tubings are disposed side-by-side.

20. In a closed, fluid-operated, free-pump system for a well, the combination of: supply, return and production tubings set side-by-side in the well and respectively adapted to convey operating fluid downwardly into the well from the surface; spent operating fluid upwardly in the well to the surface and fluid produced by the well upwardly therein to the surface; a tubular pump receiver at the lower end of and aligned with one of said tubings, said pump receiver being connected to the lower ends of said tubings and being in fluid communication with said tubings and withlthe well; a pump seat carried by said pump receiver and disposed at the lower end thereof in alignment therewith; a fluid-operated, free pump movable in said one tubing and movable into an operating position in said pumpre'ceiver wherein it is seated on said pump seat, said pump having an intake, an exhaust, an inlet and an outlet which communicate with said supply tubing, said return tubing, the well and said production tubing, respectively, when said pump is in said operating position; means for normally preventing direct flow of fluid between said tubings and the well through said pump receiver when said pump is in said operating position; and passage means communicating with one of the others of said tubings and with said pump receiver above said pump seat for applying a downward flow of fluid in said one other tubing to the lower end of said .pump to move it upwardly out of said pump receiver and through said one tubing to the surface.

21. A closed system as set forth in claim 20 wherein said passage means communicates with said return tubing and wherein said means for preventing direct flow comprises a sealing device for preventing fluid communication between said return tubing and said production tubing when said pump is in said operating position, said sealing device comprising an annular sealing element between said pump and said pump receiver.

22. A closed system as set forth in claim 20 wherein said passage means communicates with said return tubing and wherein said means for preventing direct flow comprises a sealing device for preventing fluid communication between said return tubing and said production tubing when said pump is in said operating position, said sealing device comprising a spring-loaded valve in said passage means.

23. A closed system as set forth in claim 20 wherein said one tubing is said production tubing.

24. A closed system as set forth in claim 20 wherein one tubing is said supply tubing.

25. A closed system as set forth in claim 20 wherein said one tubing is of larger diameter than either of the others of said tubings.

26. A closed system as set forth in claim 20 wherein said production tubing is of larger diameter than either of the others of said tubings.

27. In a closed, fluid-operated, free-pump system for a well, the combination of a supply tubing set in the well and adapted to convey operating fluid downwardly into the well from the surface; a return tubing set in the well and adapted to convey spent operating fluid upwardly in the well to the surface; a production tubing set in the well and adapted to convey fluid produced by the well upwardly therein to the surface; a tubular pump receiver at the lower end of and aligned with said production tubing and connected to the lower ends of said tubings, said pump receiver communicating at its upper end with said production tubing, communicating at its lower end with the well and communicating intermediate its ends with said supply and return tubings; a fluid-operated, free pump movable in said production tubing and movable into an operating position in said pump receiver, said pump having adjacent its upper end an intake and an exhaust respectively communicating with said supply and return tubings when said pump is in said operating position, and having adjacent its lower end an outlet, said inlet communicating with the well when said pump is in said operating position; a passage communicating with said pump receiver at a pair of vertically spaced points, said outlet of said pump communicating with the lower end of said passage when said pump is in said operating position, and the upper end of said passage communicating with said'pump receiver above said intake and said exhaust when said pump is in said operating position to convey fluid from said outlet into saidproduction tubing; and sealing devices for preventing direct flow between said tubings and the well when said pump i in said operatingposition.

' 28. In a closed, fluid-operated, free-pump system for a well, the combination of supply, return and production tubings set' in the well and respectively adapted to convey operating fluid downwardly into the well from the surface, spent operating fluid upwardly in the well to the surface and fluid produced by the well upwardly therein to the surface; a tubular pump receiver at the lower end of and aligned with said supply tubing, said pump receiver being connected to'the lower ends of said tubings in fluid communication therewith and being in fluid communication with the well; a fluid-operated, free pump movable in said supply tubing into an operating position in said pump receiver, said pump having an intake, an exhaust below said intake, an outlet below said exhaust and an inlet below said outlet, said intake, said exhaust, said inlet and said outlet respectively communicating with said supply tubing, said return tubing, the well and said production tubing when said pump is in said operating posiiton; an annular sealing element carried by said pump intermediate said intake and said exhaust and engageable with said pump receiver when said pump is in said operating position; another annular sealing element carried by said pump intermediate said exhaust and said outlet and engageable with said pump reeciver when said pump is in said operating position; and sealing means providing a fluid-tight seal between said inlet and said outlet when said pump is in said operating position.

29. A closed system according to claim 28 in- I cluding a passage communicating at one end with said return tubing and at its other end with said pump receiver at a point which is intermediate said other annular sealing element and said sealing means when said pump is in its operating position, said system, including a sealing device for normally preventing flow from said return tubing through said passage to said production tubing when said pump is in said operating position.

30. A system as set forth in claim 29 wherein said sealing device comprises a spring-loaded valve in said passage.

31. In a closed, fluid-operated, free-pump system, the combination of a primary tubing and a pair of secondary tubings set in the well, said primary tubing being of a size to receive a fluidoperated, free pump and providing for movement of the pump between an operating position at the lower end of said primary tubing and the surface; means interconnecting the lower ends of said tubings, said interconnecting means having passage means providing fluid communication between one of said secondary tubings and said primary tubing and having passage means providing fluid communication between the other of said secondary tubings and said primary tubing; and inlet means connected to said primary tubing and having a passage providing fluid communication between the well and said primary tubing, said inlet means having means for preventing flow of fluid from said primary tubing into the well through said passage.

32. In a closed, fluid-operated, free-pump system, the combination of: a primary tubing and a pair of secondary tubings set side-by-side in 23 the well, said primary tubing being of a size to receive a fluid-operated, free pump and providing for movement of the pump between an operating position at the lower end of said primary tubing and the surface; means interconnectin the lower ends of said tubings, said interconnecting means having passage means providing fiuid communication between one of said secondary tubings and said primary tubing and having passage means providing fluid communication between the other of said secondary tubings and said primary tubing; and inlet means connected to said primary tubing and having a passage providing fluid communication between the well and said primary tubing, said inlet means having means for preventing flow of fluid from said primary tubing into the well through said passage.

CLARENCE J. COBE-R-LY.

241 REFERENCES CITED The following references are of record in the die of this patent:

UNITED STATES PATENTS Number Name Date 971,612 Holliday Oct. 4, 1910 1,630,902 Parrish May 31, 1927 10 1,765,921 Joy June 24, 1930 2,051,243 Bowling Aug. 18, 1936 1 2,162,748 Richards 'et a1 June 20, 1939 2,230,787 Swain Feb. 4, 1941 2,230,830 Coberly Feb. 4, 1941 15 2,277,181 Zuck Mar. 24, 1942 2,327,503 Coberly Aug. 24, 1943 2,338,903 Coberly Jan, 11, 1944

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