US2851954A

US2851954A - Counterflow free pump system

Info

Publication number: US2851954A
Application number: US530499A
Authority: US
Inventors: Clarence J Coberly
Original assignee: Kobe Inc
Current assignee: Kobe Inc
Priority date: 1955-08-25
Filing date: 1955-08-25
Publication date: 1958-09-16
Anticipated expiration: 1975-09-16

Description

C. J. COBERLY COUNTERFLOW FREE PUMP SYSTEM Sept. 16, 1958 3 Sheets-Sheet 1 Filed Aug 1955 CLARENCE (f (ca Eel.

Patented Sept. 16, 1958 United States Patent Ofiice COUNTERFLOW FREE PUMP SYSTEM Clarence J. Coherly, San Mariuo, Calii, assignor to Kobe,

Inc., Huntington Park, Calif., a corporation of Call- The present inventiot. relates in general to a fluidoperated oil well pumping system and, more particularly,

' to a :free pump system of this nature.

Fluid-operated free pump systems may include either two tubings or three tubings, one of the tubings in either system being of a size to permit circulating a fluidoperated free pump therethrough between the surface of the ground and an operating position in the Well. Iii a two-tubing free pump system, often called an open system, the production fluid and the spent operating fluid discharged by the pump are mixed and conveyed to the surface in a single production tubing. In a three-tubing free pump system, commonly called a closed system, the production fluid and the spent operating fluid are con veyed to the surface separately in separate production and return tubings.

For maximum oil production with either an open system or a closed system, it is desirable toemploy as large a pump'as possible within the limited space available in the Well. Consequently, the tubing throughwhich the pump is circulated between the surface and its operating position in the well must be relatively large. With such a relatively large pump tubing taking up a substantial portion of the limited space available in the Well, any other tubings incorporated in the system must necessarily be relatively small, at least in aparallel tubing system.

In many prior fluid-operated free pump systems of either the open type or the closed type, the relatively large tubing through which the pump is circulated be tween the surface and its operating position in the well is also utilized as a supply tubing :for deliveringoperating fluid under pressure to the pump to operate the pump: Consequently, the production fluid and the spent operating fluid discharged by the pump must be conveyed to the surface in a tubing or tubings which are smaller than the pump or supply tubing, the productionfluid and spent operating fluid being mixed and conveyed to the" surface in a single, smaller production tubingin the case of an open system, and being conveyed to the surface separately in smaller production and return t-ubing's, respectively, in the case of a closed system. In such prior systems, the operating fluid under pressure is delivered to the pump or supply tubing both to move the pump downward-1y into its operating position and to operate the pump, the direction of operating fluid flow being reversed to'oircu late the pump to the surface. In other Words, theojr crating fluid is delivered to the production tubing to move the pump upwardly through the supply tubing iii-the case of an open system, and is delivered to one or both of the production and return tubings' temovettte pum up- 2 ward-1 y through the supply tubing in the case of a closed system.

With systems of the foregoing nature, there are in stances wherein excessive friction losses are encountered due to the fact that a relatively large volume of production fluid must be conveyed to the surface through a relatively small tubing, particularly in Wells, such as shallow wells, wherein pumping conditions permit the use of a fluid-operated pump having a pump section capable of displacing a larger volume of fluid than the motor or engine section thereof. Thus, the volume of production fluid conveyed to the surface is larger than the volume of operating fluid conveyed to the pump. Excessive friction losses may be encountered under such conditions even in a closed system wherein the relatively large v'olume of production fluid is conveyed to the surface separately from the spent operating fluid discharged by the pump. However, the problem is particularly severe in the case of an open system under such conditions because of the fact that the spent operating fluid, as

well as the relatively large volume of production fluid,

must be conveyed to the surface through a single, small, production tubing. In an open system, the effect of this friction is' amplified because of the fact that the friction in the small tubing is both an additional load that the pump must operate against, and a frictional back pressure on flie engine. If, for instance, the 'pump-to-engine area ratio is 1.5 and this friction loss is 200 p. s. i., then this is reflected in an engine pressure increase of 1.5 X200 p. s. i., or 300 p. s. i., plus 200 p. s. i. backpressure, making the total frictional pressure on the engine 500 p. s. 1.

in order to minimize friction losses in a fluid-operated free pump system wherein the volume of production fluid, or the volume of a mixture of the production fluid and the spent operating fluid, is larger than the volume of the operating fluid supplied to the pump, it is desirable to employ the larger, pump tubing as the production tubing instead of as the suply tubing, and to employ a smaller tubing as the supply tubing for conveying the operating fluid under pressure downwardly to the pump, a primary object of the invention being to provide a system of this nature.

One known way of accomplishing the foregoing is by means of the closed, fluid-operated free pump system disclosed in my Patent No. 2,589,671. In this system, a relatively large pump tubing is utilized to convey the production fluid discharged by the pump to the surface. The operating fluid under pressure is supplied to the pump through a relatively small supply tubing, and the spent operating fluid is returned to the surface through a relatively small return tubing separate from the production' and supply tubings. In this system, the pump is circulated into the hole through the production tubing and the displaced fluid returns to the surface through one or both of the supply and return tubings. In order to circulate the pump to the surface, the operating fluid is delivered to the small tubing normally used to return the spent operating fluid, so as to unseat the pump, the pump being moved to the surface by delivering fluid to one or both of the supply and returntubings. With this system, no hydraulic forces tending to unseat the pump are applied thereto during operation of the pump so that a conventional, or standard, free pump may be used without modification.

Another known way of utilizing a relatively large pump tubing to convey fluid discharged by the pump to the surface involves a two-tubing, or open, system wherein the production fluid and the spent operating fluid discharged by the pump are mixed and conveyed to the surface in a single large production tubing. In such a system, the pump is circulated into the hole through the production tubing by delivering operating fluid to the upper end of the production tubing and the pump is operated and circulated to the surface by operating fluid delivered to the smaller, supply tubing. However, because of the fact that the operating fluid for operating the pump and the operating fluid for circulating the pump to the surface are both delivered to the supply tubing, some means must be provided for preventing unseating of the pump when operating fluid is delivered to the supply tubing to operate the pump, and for permitting the pump to unseat and to move upwardly through the production tubing to the surface when operating fluid is delivered through the supply tubing for this purpose. With the prior system under consideration, in order to provide for biasing of the pump upwardly by operating fluid delivered through the supply tubing when it is desired to circulate the pump to the surface through the production tubing, it is necessary to use a nonstandard free pump which must be modified while it is in the well. This is accomplished by circulating a pump retriever downwardly through the production tubing, the pump retriever latching onto the pump and providing a downwardly-facing area on which operating fluid may act to bias the pump upwardly. Thereafter, the pump and its retriever may be circulated to the surface through the production tubing by circulating operating fluid downwardly through the supply tubing. However, a substantial period of time is required to circulate the pump retriever downwardly through the production tubing to the pump, which is obviously undesirable since it approximately doubles the length of time required to remove the pump from the well as compared with the time required to remove the pump with prior systems of the nature discussed earlier herein.

Consequently, an important object of the present invention is to provide a fluid-operated free pump system in which a pump unit, including a standard free pump, is circulated between the surface and its operating position through the production tubing without materially increasing the length of time required to remove the unit from the well. attains the hereinbefore-discussed advantages of using the pump tubing as the production tubing, without, however, incurring the penalty of a substantial increase in the time required to circulate the pump unit out of the well, which is an important feature of the invention.

In the system disclosed in my co-pending application Serial No. 487,303, filed February 10, 1955, the foregoing is accomplished by providing the pump unit with a downwardly-facing area which is exposed to fluid pressure in the supply tubing and by providing the pump unit with latch means for latching the pump unit in its operating position in the well against the resulting upward bias, the latch means being retractable by a predetermined pressure developed in the production tubing when it is desired to remove the pump unit from the well. Thus, the latch means is hydraulically operable from the surface to latch the pump unit in and release it from its operating position, thereby avoiding any substantial increase in the time required to circulate the pump unit out of the well.

The present invention attains the forgoing general result by providing the pump unit with a downwardlyfacing area to which fluid pressure from the supply tubing may be applied to move the pump unit upwardly, and by providing means, preferably carried by the pump Thus, the present invention 7 unit, for preventing communication between such area and the supply tubing when it is desired to operate the pump, together with means, also preferably carried by the pump unit, for establishing fluid comrnuincation between such area and the supply tubing when it is desired to unseat the pump unit and move it upwardly to the surface, an important object of the invention being to provide such a construction.

Another object of the invention is to provide means for establishing fluid communication bewteen the supply tubing and the specified area of the pump unit which is controllable from the surface. An important object in this connection is to provide means for establishing communication between such area of the pump and the supply tubing which is actuable by a predetermined pressure in the production tubing. Consequently, the specified area of the pump unit may be placed in fluid communication with the supply tubing merely by selectively pressurizing the production tubing, whereupon the pump unit may be displaced upwardly by pressurizing the supply tubing, which are important features of the invention.

With the foregoing construction, the means for supplying fluid under pressure to the downwardly-facing area of the pump unit to move the pump unit upwardly may be activated or rendered operative very quickly, without adding appreciably to the time required to remove the pump unit from the well. Thus, the pump unit may be removed from the well without incurring the penalty of a substantial increase in the time required to circulate the pump unit out of the well, while still attaining the hereinbefore discussed advantages of using the pump tubing as the production tubing, which are important features of the invention also.

Considering the present invention more specifically now, an object thereof is to provide a pump unit which includes adjacent the lower end thereof a housing hav ing therein valve means for controlling fluid communication between the supply tubing and the specified downwardly-facing area of the pump unit, the latter having a passage therethrough which is controlled by such valve means and which connects the supply tubing to the specified area of the pump unit when the pump unit is seated in its operating position in the well.

Another object is to provide a valve means including a valve located in the housing mentioned and movable between open and closed positions, and including pressure-actuable means, responsive to pressure in the production tubing, for moving the valve from its closed position to its open position in response to development of a predetermined pressure in the production tubing, thereby establishing communication between the supply tubing and the downwardly-facing area of the pump unit to permit application of fluid pressure from the supply tubing to such area to move the pump unit upwardly out of its operating position.

Another object is to provide a valve means wherein the valve is a ball valve located between and seated on two opposed members when the valve is in its closed position, one of the opposed members being a valve seat and the other being a valve follower spring biased toward the valve seat. A related object is to provide means responsive to pressure in the production tubing for displacing the ball valve laterally out from between the valve seat and follower into its open position, including a piston-like cage for the valve having one end exposed to fluid pressure in the production tubing. In this connection, an object is to provide a construction in which the valve cannot readily be returned to its closed position by the application of fluid pressure thereto, or to its cage, once the valve has been moved into its open position in the manner indicated.

Thus, with the foregoing construction, the pump unit may be installed,.operated and removed readily with substantially no increase in the time required to install and remove the unit over the time required with prior systems utilizing the pump tubing as the supply tubing, and in much less time than any system which requires the use of a pump retriever which must be sent down after the pump. Briefly, with the present invention, the pump unit can be installed, operated and removed by inserting the pump unit into the upper end of the production tubing, supplying fluid to the production tubing above the pump unit to circulate it downwardly through the production tubing to its operating position, the pump unit being held in its operating position by fluid pressure in the production tubing thereabove, applying normal operating-fluid pressure to the supply tubing to operate the pump, applying to the production tubing a fluid pressure substantially higher than the pressure required to circulate the pump unit into its operating position so as to open the hereinbefore discussed valve means to establish fluid communication between the specified downwardly-facing area of the pump unit and the supply tubing, and thereafter supplying fluid under pressure to the Supply tubing to circulate the pump unit to the surface through the production tubing. The selective pressurization of the production tubing necessary to establish communication between the specified area of the pump unit and the supply tubing may be accomplished very quickly, which is an important feature of the invention.

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

Fig. 1 is a. utility view, partially in vertical section and partially in elevation, illustrating a fluid-operated free pump system of the invention as installed in a well;

Fig. 2 is an enlarged, fragmentary, transverse sectional view taken along the arrowed line 22 of Fig. 1;

Figs. 3, 4 and are partially sectional and partially elevational views taken along the arrowed lines 3-3 of Fig. 2 Fig. 4 being a downward continuation of Fig. 3 and Fig. 5 being a downward continuation of Fig. 4;

Fig. 6 is a view, partially in vertical section and partially in elevation, taken along the arrowed line 6-6 of Fig. 2 and corresponding to, i. e., occupying the same vertical zone as, Fig. 4;

Fig. 7 is a further enlarged, fragmentary, vertical sectional view duplicating a portion of Fig. 5 and illustrating a valve means of the pump unit of the invention on a larger scale, the valve means being shown closed;

Fig. 8 is a duplicate of Fig. 7, except that the valve means is shown open; and

Figs. 9 and 10 are fragmentary, transverse sectional views respectively taken along the arrowed lines 9-9 and 10-10 of Fig. 7 of the drawings.

Referring particularly to Fig. 1 of the drawings, the numeral 12 designates a well casing which is set in a well and which is provided with perforations, not shown,

to admit into the casing fluids from surrounding, productive formations. The casing 12 is equipped with a casing head 14 which supports parallel production and supply tubing-

s

16 and 18 in the casing, these tubings extending downwardly below the well fluid level in the casing. The production and

supply tubings

16 and 18 communicate at their upper ends with a four-way valve 20 operated by a handle 22, this valve selectively connecting the production tubing and the supply tubing with an operating fluid supply line 24 and a production fluid disposal line 26. Thus, by means of the valve 20, either the production tubing 16, or the supply tubing 18, may be pressurized with operating fluid from the supply line 24.

'In accordance with the invention, the production tubing 16 is of relatively large diameter to accommodate a fluid-operated free pump unit 28 which, may be inserted into theupper end of the production tubing by removing a closure 30 which may contain the usual free pump catcher.

tail in my Patent No. 2,311,157.

The pump unit 28 is circulated downwardly through the production tubing 16 by connecting the upper end of the production tubing to the supply line 24 until the pump unit arrives at its operating position in a housing which is designated generally by the numeral 32 and which is an assembly of components to be described in more detail hereinafter. The housing 32 is connected to the lower end of the production tubing 16 and is also connected to the supply tubing 18, all as will be discussed in more detail hereinafter. Y

The pump unit 28 includes a fluid-operated pump 34 of the reciprocating type to the upper end of which is connected a packer nose 36 to convert it to a free pump. While the pump 34 may be of various types within the scope of the present invention, the pump 34, in the particular embodiment illustrated, is of the double-acting type and is similar to the one disclosed in complete de- Consequently, a detailed description of the pump. 34 herein is unnecessary, reference being made to my said Patent No. 2,311,157 for a complete description. Considering the pump 34 in a very general way for the present, it being considered in somewhat more detail hereinafter, it includes the usual engine or motor section 38 and the usual pump section 40 below the engine section, as best shown in Fig. 4 of the drawings. The engine section 38 includes an intake 41 for operating fluid under pressure and includes an exhaust 42 for spent operating fluid, the engine section 38 also including a fluid-operated valve means 44 which controls the application of operating fluid intake and exhaust pressures to a motor or engine piston, not shown, in the engine section 38 to produce reciprocatory movement of such piston. Coupled to the engine piston in the engine section 38 is a pump piston, not shown, in the pump sec tion 40 so that reciprocatory movement of the engine piston results in simultaneous reciprocatory movement of the pump piston to draw in well fluid through an inlet 46 and to discharge such well fluid as production fluid through either oftwo outlets 48 and 5'0, depending on the direction of pump piston movement in this doubleacting pump. As more fully described in my aforesaid Patent No. 2,311,157, the pump section 40 is provided with inlet and outlet valves, not shown, which control the admission of well fluid into and the discharge of production fluid from the ends of the pump cylinder in which the pump piston reciprocates.

The housing 32 carries at its lower end a standing valve assembly 52 on which the pump unit 26 seats when it is in its operating position in the housing. Both the housing 32 and the standing valve assembly 52 are described in detail and claimed in my hereinbefore-identified application Serial No. 487,303, so that a detailed description of these components herein will be unnecessary. As shown in Fig. 5 of the drawings, the housing 32 includes at its lower end a bottom shoe 54 providing a seat 56 for the standing valve assembly 52, which ex-- tends downwardly into an inlet pipe 58 depending from the bottom shoe. Well fluid enters the pump 34 through the standing valve assembly 52, the latter being provided with a standing valve 60 adapted to seat on a standing valve seat 62. The lower end of the pump unit 28 is provided with a tubular inlet or bottom plug 64 which is adapted to seat on a pump-unit seat 66 when the pump unit 23 is in its operating position in the housing 32. With this construction, well fluid can enter the housing 32 only through the inlet 46 leading into the pump section 40 of the pump 34.

Continuing to refer to Fig. 5 of the drawings, communicating with an internal annular channel 68 in the bottom shoe 54 above the seat 56 for the standing valve assembly 52 is a port 70 which communicates, in turn, with a vertical passage 72 in the bottom shoe. The passage 72 communicates, in turn, with a vertical. pipe 74 which extends upwardly into communication with a vertical passage 76, Fig. 4, in a sealing collar 78 which forms end of the production tubing 16 is threaded. Thus, as

will be described in more detail hereinafter, production fluid discharged by the pump 34 may flow from the lower end of the housing 32 into the upper end thereof by way of the channel 68, the port 70, the passage 72, the pipe 74, the passage 76, the port 80 and the channel 82. From this point, the production fluid flows upwardly through the sealing collar 78 and the enlarged tube 84 into the lower end of the production tubing 16, the internal diameter of the enlarged tube 84 being suflicient to permit the production fluid to bypass the packer nose 36.

The sealing collar 78 and the bottom shoe 54 are interconnected by a pump housing tube 86 in the manner more fully described in my aforementioned copending application. As shown in Fig. 6 of the drawings, the lower end of the supply tubing 18 is threaded into the upper end of a vertical passage 88 in the sealing collar 78, the lower end of this passage communicating with a port 90 in the sealing collar which, in turn, communicates with an internal annular channel 92 in the sealing collar below the channel 82. The sealing collar 78 is provided with a liner 94 which is pressed thereinto and which is provided with radial ports 96 communicating at their outer ends with the channel 92 and communicating at their inner ends with an internal annular channel 98 in the liner itself. Similarly, adverting to Fig. of the drawings, the bottom shoe 54 is provided with a liner 100 having therein at its upper end notch-like ports 102 which communicate at their outer ends with the channel 68 in the bottom shoe and which communicate at their inner ends with an annular channel 104 in the liner itself. The liner 100 is also provided with radial ports 106 therein below the ports 102 for a purpose to be described.

As shown in Figs. 4 and 6 of the drawings, the pump 34 is provided, below the packer nose 36, with O-

rings

108 and 110 respectively located above and below the operating fluid intake 41 of the pump. When the pump unit 28 is seated in the housing 32, the O-

rings

108 and 110 are also located above and below, respectively, the internal annular channel 98 in the liner 94 so that operating fluid under pressure fromv the supply tubing 18 may enter the operating fluid intake 41 of the pump through the channel 98, the ports 96, the channel 92, the port 90 and the passage 88. The O-ring 110 isolates the operating fluid intake 41 from an annular space 112 around the pump 34, and between it and the pump housing tube 86. The lower end of this annular space is closed by an O-ring 114, Fig. 5, carried by the pump unit 28 and engageable with the liner 180 in the bottom shoe 54 below the annular channel 68 therein. Thus, spent operating fluid discharged from the operating fluid exhaust 32 of the pump 34, and production fluid discharged from the upper and lower outlets 48 and 50 of the pump, are mixed in the annular space 112 around the pump, the mixture of production fluid and spent operating fluid flowing from this space into the production tubing 16 above the pump unit 28 along the avenue hereinbefore described.

With the installation as thus far described, when the pump unit 28 is seated on its seat 66, it is held on its seat by the pressure of the column of fluid in the production tubing 16. The reason for this is that the pressure of the fluid column in the production tubing 16 acts downwardly on the entire cross-sectional area of the pump unit 28, whereas part of the cross-sectional area of the pump unit, i. e., the part within the zone of engagement between the inlet plug 64 and the seat 66, is exposed to fluid pressure in the well through the standing valve assembly 62, the fluid pressure in the well normally being much less than the production column pressure. Consequently,

, s a downward fluid pressure differential is applied to the pump unit 28 to hold it on its seat 66 once it is seated, the manner in which it is seated thereon being discussed hereinafter.

In the light of the foregoing, it will be apparent that means must be provided for unseating the pump. In accordance with the present invention, this is accomplished by applying to a downwardly-facing area of the pump unit 28 a fluid pressure sufiiciently high to force the pump unit off its seat and move it upwardly in the housing 32. M .o cifically, the present invention provides means for delivering fluid under pressure from the supply tubing 18 to a downwardly-facing area 116 of the pump unit to unseat the pump unit and move it upwardly in the housing 32 a predetermined distance as hereinafter described, the area 116 being, in the particular construction illustrated, an annular area of the inlet plug 64 equal to the difference between the cross-sectional area of the pump unit 28 and the area within the line of sealing engagement between the inlet plug and the pump-unit seat 66. Once the pump unit 28 has been displaced upwardly in the housing 32 the predetermined distance mentioned, an upper packer 118 of the packer nose 36 moves upwardly out of the enlarged tube 84 into the production tubing 16 and into engagement with the inner wall thereof. Thereafter, the fluid under pressure delivered to the lower end of the pump unit 28 from the supply tubing 18 acts on the upper packer 118 to continue the upward movement of the pump unit, it being apparent that once the pump unit has been unseated, the applied pressure acts on the entire cross-sectional area of the pump unit. Eventually, a lower packer 120 of the packer nose 36 also enters the production tubing 16 to minimize the escape of fluid under pressure upwardly past the pump unit, the upper and

lower packers

118 and 120 being carried by a packer mandrel 122 forming part of the packer'nose 36 and terminating at its upper end in a tapered head 124 engageable by the aforementioned pump catcher carried by the closure 30 at the surface.

Considering now the manner in which fluid under pressure from the supply tubing 18 is delivered to the area 116 of the pump unit 28 when it is desired to unseat the pump unit, carried by the pump unit adjacent the lower end thereof is a pressure-actuable valve assembly which controls a fluid passage 132 communicating at one end with the supply tubing and communicating at its other end with the area 116, the valve assembly 130 normally closing this passage, but being actuable by pressure developed within the production tubing 16 to open same when it is desired to remove the pump unit from the well. In the particular construction illustrated, wherein the particular pump 34 hereinbefore discussed is utilized, the

fluid passage 132 extends through the pump unit 28 from the operating fluid intake 41 of the pump 34 to the area 116 at the lower end of the pump unit. More particularly, the pump 34 is provided with a central axial passage 134 which forms part of the over-all fluid passage 132 between the supply tubing 18 and the area 16, the passage 134 communicating at its upper end with the operating fluid intake 41 and, as best shown in Figs. 4 and S of the drawings,-extending through the valve means 44 of the engine section 38, and through the pump section 40, to a zone below the pump section. Part of the central passage 134 through the pump 34 is formed by a pilot valve 138 and a balance tube 136, which is provided to hydraulically balance the pilot valve as more fully disclosed in my aforementioned Patent No. 2,311,157. The pilot valve 138 is always contained within the engine section 38 and the packer nose assembly 36. At the bottom of the stroke, the valve 138 is in the position shown by the solid lines, and at the top of the stroke it extends into the packer nose assembly as shown dotted. Normally, the lower end of the balance tube 136 is closed in a standard pump 34 of the character under consideration. However, for the purposes of the present invention, the lower end of the balance tube 1361s left open and ex- 9 tendsinto the valvelassembly 130 in a manner. to bedescribed so as to enable the'balance tube tobequsedas a part ofthe fluid passage-132 for conveyingfluidun'der pressure fromtthe supply tubing'18" to" the area 116 of thepumpunit'28.

Considering-the valveassembly130 now in more detail,,it includes a housing 140 which, as, best shown in Fig: of"the drawings, is interposedbetweenthe'standard lower. tube 142 of the pump 34 and the inlet plug 64 thereof: More particularly, the h0USiI1g140iSJSlIiOWI1 asthreadedintothe lower end of "thetnormal lower'tube 142, and as having the inlet plug64: threaded thereinto, the O-ring 114' being shown as carried by the housing 140: The housing-140 is provided-with aplurality'of vertical passages'144 therein through; whichwellfluid may flow from thetu'bular inlet'plug 64 to the inlet valvesof: the pump section 40*of the pump 34, these passages being bestishown in Figs. 7 to of the drawings.

The fluid passage 132 extends through the housing 140'of the'valve'assembly130 and includes a central counterbore 148 in the housing== into which a" reduced end 150'of-the balance tube136-extends,,anO ring 152 being'provided'for' sealing purposes; A heavy'compression'spring1S4'is1seatedon th'elowerend of the balance tube 136 andengages an'annular flange 156' onia'tubular valve follower 158 to bias same'downwardlytoward'the bottorn ofthe' counterbore148; the flange'156being;ene gageable with-the bottom of this counterbore; as shown in Fig; 8; to limit downward movement of thevalve follower 1'58: The-latter extendsthrough a bore 160' in the housing'140' into a' transverse bore or "cylinder 162 therein which is closed at one end and which commun'r cates'at its other end'withan' annular channel 164 in theexterior of the'housing 140. Facing and'aligned with the movable valve foll0wer'158 is a stationary valve seat-166 formed-ma member 168 threaded into a' cen" tral vertical bore 170' in the housing 140 and sealed" by an"0'-'ring'172.- The member168has an axial passage 174th'erein'which terminates in radial passage 174 therein whichterminates in radial passages orports 176; the latter communicatingat their outer ends with an an-' nular channel 178- in the" member 168. This channel communicates withthe inner'ends of radial passages 180' in'=the-housing- 140; these radial'passagescommunicating at their' outerendswithlongitudinal channels 182 in th'e housing. Inturn, these channels communicate with an annular space 184 around the housing 140 and the inlet plug 64 and within "the bottom shoe 54-, this annular space leadingto the downwardly-facing area'116' of'the' pump unit 28.

Disposed within the transverse bore 01" cylinder" 162 is a pressure-actuable valve means186 for-opening and closing: the fluid passage 132'throughthe pump unit28i- The avalve.=means-186includes a'ball valve 188 which is adapted 'to' be: disposed between the follower158-and"theseat: 166 in seating engagement therewith-to close thepassage:.132,the ball valve also being movable to one side: ofthe follower:158 and the seat 156'; as 'shown 'in Figz 8rofzthewdrawings, to open the fluid passage 132 and thereby establish communication between the supply tubingslsr 'andthe area 1160f the pump unit 28;

The valve means'186 also includes a piston-like'cage 190: for the ball :valve 188, the cage having thereth'rough aatransverse bore 192 in which the ball valve is loosely" disposed. The cage 190 has another bore- 194- therethrough which; registers with the valve seat 166*a11d-f the valve: follower 158 when the valve means 186 is inthe position shown in Fig.8, the bore 194- forming part of the fluid passage-132.. In order to prevent rotation of thecage 190 and inorder to limit its movement in both directions, it'is provided in" one sidewith a groove 196" which receives a projecting-portion of the member 168;

thee-widthof thegroove196 being'substantially equal to :thetdiameter of the member 168 and the ends of the grooveibeingengageable with the member 168'toserve as stops for limiting movement of the. cage in both direc tions. A similar groove 198 is provided"in.th'e opposite side ofthe ca'ge 190" to receivethe'valve follower- 15:8 Preferably, the grooves"196'and'198*are identicalso' that the, cage 19(T'may be installedinitially in either of two positions'spacedf apart; The cage isprovidd adjacent the closed'endof'the cylinder 162'witl1' anaxial bore 200 through which fluid may escape when the cage is'moved'to'the left, .asviewed in the'drawings, the'b'ore 200' communicating with the bore 192 in' whichthe' ball valve 188 is loosely disposed. The other end" of the cage 190 is providedwith an O-ring 202 to provide a fiuid-tightseal, this end ofthe cage also beingprovided with" athreaded' bore 204 therein to receive a suitable tool, notsh'own; for moving the valve means'186 from the position shown in Fig.- 8 of the drawings" to that shown in Fig; 7 thereof'toreset' the valve means in'its closedposition;v It will'be'notedthat the openendof the-cylinder 162, and'thus the corresponding'endofjthe' cage 190 communicate" with the channel=164,' which; in turn, communicates with the ports 106 leading to the production tubing 16' along the avenue hereinbefore dis cussed.

The foregoing, completes the description of'the structure ofthecounterflowfree =pump system'of the invention, and the over-all operation thereof will now be ex= plained'.

Prior'to running the pump unit'28 into thewell, the cage"190"is-set in'thepositionshown in Fig. 7 of the 'drawingsto'seat'theball valve- 188 on the seat 166 and the fllower 158, thereby closingthe fluid passage132 through'-thepu'rnpj*unit: I f the cage 190 is initially in the"posit-ionshown 'in Fig. 8 of the drawings, any suit; able tool, such as-a screw, may be threaded-into the'bore 20'4=-to--draw*-the cage into *the'desired position. The force applied'to the-"valve follower 158' by the spring-1541s sufliciently 'large to prevent movement of' the valve cage-190 from the position shown in Fig. 7 into the posi= tion shown in Fig; 8 in-responseto any pressures'which may be applied to the exposed 'end of the valve cage in running the pump unit intothe well. In other'words; thespring. 154 'prevents movement of the valve means 186 'into' its open positien in responseto any pressure appliedi towhe exposed end'of thecage"190 whichfis less than the predetermined minimum pressure for which theval-ve' means -is:designed, which predeterminedmini mum pressure is substantially higher than-any pressure which might-inadvertently be applied to the cage while runningthe pump unit in and seating it. Preferably; the predetermined minimum pressure required to move the' valve means 186 to itsopen position is at least as high as the pressure which must be applied to the area ll6' ofithe pump unit 28 to unseatit. If this werenot the ca'se, the ball valve 188 might be returned to its closed position-upon application of pressure to the area- 116 of th'e'pumpunit 28 to unseat it, since the fluid passage 132 le'adingto' thearea116cornmunicates with the closed end of; the cylinder-162' in which the cage 190 is" dis posed-' throughwh e' bore 200. By making'the predeter minedrninimum pressure requiredto open the valve means 186 at-leas't"as high as the pressure requiredto unseat th'e pumpunit28, the' valve means 186 cannot be inadvertentlyopened when it is'supposed to be closed,

and cannot beinadvertently closed whenit' is'intended" ing the operating fluid pressure which can be applied to the production tubing 16 under such conditions to a value less than the predetermined minimum pressure required to open the valve means 186, thereby insuring against any possibility of opening the valve means 186 while the pump unit is being circulated into its operating position.

Under the foregoing conditions, the pump unit 28 moves downwardly through the production tubing 16 into the housing 32." The fluid beneath the pump unit 28 is displaced upwardly to the surface through the supply tubing 18 until such time as the O-ring 114 moves below the

ports

102 and 106, the displaced fluid being directed from the supply tubing into the disposal line 26 by the valve 20. After the O-ring 114 passes the

ports

102 and 106, the small amount of fluid in the space between the lower end of the pump unit 28 and the standing valve assembly 52 cannot be displaced in the foregoing manner. Instead, this trapped fluid is displaced upwardly through the tubular inlet plug 64, through the passages 144, and then through the inlet and outlet valves in the pump section 40 of the pump 34, being discharged from the production fluid outlets 48 and 50 into the annular space 112 around the pump. From this annular space, the fluid displaced from beneath the pump unit 28 in the foregoing manner will flow into the supply tubing 18 until such time as the O-ring 110 moves below the annular channel 98 in the liner 94 in the scaling collar 78. Thereafter, the fluid displaced from beneath the pump unit 28 into the annular space 112 through the [pump section 40 in the foregoing manner enters the operating fluid exhaust 42 of the engine section 38 and flows into the engine section. This results in displacement of the engine or motor piston in the engine section 38 to discharge fluid from the opposite side of the engine or motor piston through the operating fluid intake 41 of the engine section, the fluid discharged from the intake 41 flowing into the supply tubing 18 by way of the annular channel 98, the ports 96, the annular channel 92, the port 90 and the passage 88. In this manner, all of the fluid which is displaced from beneath the pump unit 28 ultimately reaches the supply tubing 18 until such time .as the pump unit is seated on the standing valve assembly 52. If necessary, the pump unit can be forced onto its seat 66 by the application of pressure to the production tubing 16.

After the pump unit 28 has been run in and seated in the foregoing manner, the valve 20 is then operated to place the supply tubing 18 in communication with the operating-fluid supply line 24 and to place the produc-' tion tubing 16 in communication with the productionfluid disposal line 26. Consequently, operating fluid under pressure is delivered to the pump 34 through the supply tubing 18 to operate the pump, the operating fluid under pressure being delivered from the supply tubing to the operating-fluid intake 41 of the engine section 38 by way of the passage 88, the port 90, the annular channel 92, the ports 96 and the annular channel 98, which communicates with the intake 41. The spent operating fluid discharged by the engine section 38 enters the annular space 112 around the pump 34 from the operating-fluid exhaust 42 of the engine section. The reciprocatory movement of the engine piston within the engine section 38 is communicated to the pump piston within the pump section 40 to pump well fluid into the annular space 112 as production fluid, the well fluid entering the inlet valves of the pump section 40 through the standing valve assembly 52, the tubular inlet plug 64 and the passages 144. From the outlet valves of the pump section 40, the production fluid flows through the outlets 48 and 50 of the pump section 40 into the annular space 112. From the annular space 112, the mixture of spent operating fluid and production fluid discharged by the engine and pump

sections

38 and 40 of the pump 34 flows through the annular channel 104, the

12 ports 102, the annular channel 68, the port 70, the passage 72, the pipe 74, the passage 76, the port 80, the annular channel 82 and the enlarged tube 84 into the production tubing 16, this mixture flowing around the

packers

118 and 120 as it flows through the enlarged tube 84.

When it is desired to remove the pump unit 28 from the well, the valve 20 is operated to again place the production tubing 16 in communication with the operating-fluid supply line 24. The pressure in the production tubing 16 is then increased to a value in excess of that required to move the valve means 186 to its open position, the pressure required to accomplish this being, as hereinbefore discussed, at least as great as the pressure which must be applied to the area 116 to unseat the pump unit. The pressure developed in the production tubing 16 to open the valve means 186 is applied to the exposed end of the cage 190 through the annular channel 164, the ports 106, the annular channel 68, the port 70, the passage 72, the pipe 74, the passage 76, the port 80, the annular channel 82 and the enlarged tube 84. The pressure thus'applied to the exposed end of the cage 190 moves this cage to the left, as viewed in the drawings, to move the ball valve 188 off its seat 166, fluid in the cylinder 162 to the left of the cage 190 escaping through the port 200. The valve means 186 will remain in its open position so long as no pressure is developed in the fluid passage 132 greater than that required to unseat the pump unit 28, it being impossible to develop any higher pressure than this under any normal conditions.

Once the valve means 186 has been opened in the foregoing manner to open the fluid passage 132, the valve 20 is again operated to connect the supply tubing 18 in communication with the operating-fluid supply line 24 and to connect the production tubing 16 in communication with the production-fluid disposal line 26. Operating fluid under pressure is now delivered downwardly through the supply tubing 18 and the fluid passage 132 to unseat the pump unit 28 and move it upwardly in the housing 32. More particularly, under such conditions, the operating fluid under pressure flows from the supply tubing 18 through the passage 88, the port 90, the annular channel 92, the ports 96 and the annular channel 98 into the operating-fluid intake 41 of the engine section 38. From the intake 41, it flows through the central passage 134 of the pump 34, which central passage includes the valve means 144 and the balance tube 136. From the latter, the operating fluid under pressure flows through the counterbore 148, the tubular valve follower 158, the bore 194, the passage 174, the ports 176, the annular channel 178, the ports and the longitudinal channels 182 into the annular space 184 around the inlet plug 64. The operating fluid under pressure reaching the annular space 184 by the foregoing avenue acts on the downwardly-facing area 116 of the pump unit 28 to unseat the pump unit and move it upwardly in the housing 32. By the time the O-ring 114 at the lower end of the pump unit 28 moves upwardly past the

ports

106 and 102, the upper packer 118 leaves the enlarged tube 84 and enters the production tubing 16 proper to take the operating fluid pressure applied in the foregoing manner below the pump unit. Eventually, both

packers

118 and 120 are disposed in the production tubing 16 to carry the pump unit 28 upwardly through the production tubing as operating fluid under pressure continues to be delivered to the production tubing below the pump unit through the supply tubing. Once the pump unit 28 reaches the surface, it is caught by the pump catcher carrier by the closure 30, whereupon the closure may be removed to remove the pump unit.

Thus, the valve means 186 is normally closed, while the pump unit 28 is being run in and is being operated, to prevent the application of operating fluid to the area 116 to unseat the pump unit, the production column pres sure above the pump unit holding it on .itsiseat while it is in operation. By selectively pressuriiing the produc: tion tubing 16, the valve means 186 may beopenedto permit the application of fluid pressure from.the supply tubing 18to the area 116 to unseat the pump. The time required to accomplish this"is-very short southat the overalLtime-required for installing andremovinglhe pump unitz28 is not appreciably increased over that. required with prior systems wherein the pumptubing is utilized as the: supply tubing and wherein the: PIOdHCtlOIIzflLliGl; and the, spent operating fluid are conveyedto the surface through a. second, smaller tubing; Thus, thepresent invention provides the advantages of using the large pump tubing as the production tubing in a fluid-operated free pump system of the open type, without any appreciable increase in the time required for installation and removal of the pump unit, which are important features of the invention.

Although I have disclosed an exemplary embodiment of my invention herein for purposes of illustration, it will be understood that various changes, modifications and substitutions may be incorporated in such embodiment without departing from the spirit of the invention as defined by the claims allowed me and appearing hereinafter.

I claim as my invention:

1. An apparatus for installing, operating and removing a free pump unit for use in a well tubing system which includes a production tubing of a size to receive said pump unit and having a housing at the lower end thereof, and which includes a supply tubing communicating with said housing, said pump unit including a fluid-operated pump and having a downwardly-facing area to which fluid pressure is applicable to move said pump unit upwardly, said apparatus including: means for supplying fluid to said production tubing above said pump unit with said pump unit in said production tubing to move said pump unit downwardly through said production tubing into said housing; means for supplying fluid under pressure to said supply tubing when said pump unit is in said housing to operate said pump; means for preventing fluid communication between said supply tubing and said area while fluid under pressure is being delivered to said supply tubing for the purpose of operating said pump; and means for establishing fluid communication between said supply tubing and said area when it is desired to remove said pump unit, whereby to move said pump unit upwardly out of said housing and through said production tubing to the upper end thereof.

2. In a fluid-operated free pump system, the combination of: a supply tubing and a production tubing set in a well, said supply tubing being outside said production tubing, said production tubing having a housing at the lower end thereof with which said supply tubing communicates; a free pump unit, including a fluid-operated pump, movable through said production tubing with substantially a piston fit therein into said housing and having a downwardly-facing area, said pump being operable in said housing by operating fluid under pressure supplied thereto through said supply tubing to pump fluid from the well into said production tubing, and said pump unit being capable of being biased upwardly in said housing by fluid under pressure from said supply tubing applied to said downwardly-facing area thereof; and valve means for establishing fluid communication between said supplytubing and said area when it is desired to move said pump unit upwardly, said valve means forming a part of and being movable with said pump unit.

3. In a fluid-operated free pump system, the combination of: a supply tubing and a production tubing set in a well, said supply tubing being outside said production tubing, said production tubing having a housing at the lower end thereof with which said supply tubing communicates; a free pump unit movable through said production tubing with substantially a piston .fit therein into saidhousingandliaving a downwardly-facing area;therea on, said pump unit being capable of being biased up wardly in said housing by fluid under pressure applied to said area, andsaid pump unit including a fluid-oper ated pump which is operable in said housing by operating fl'uidunder pressure supplied thereto-through said'supply tubing to' pump fluid'from th'e welll'into said production tubing; means providing a fluidlpassage between said" supply tubing and'said'area; valve means in said passage for opening and closing same, said'valve means forming a part of and being movable with said pumpunit; and meansfor operating saidvalve means.

4; In a fluid-operated free pump system, the combination of: a supply tubing and a production tubing set in a well, said supply tubing being outside said production tubing, said production tubing having a housing at the lower end thereof with which said supply tubing cornmunicates; a free pump unit movable through said production tubing with substantially a piston fit therein into said housing and having a downwardly-facing area thereon, said pump unit being capable of being biased upwardly in said housing by fluid under pressure applied to said area, and said pump unit including a fluidoperated pump which is operable in said housing by operating fluid under pressure supplied thereto through said supply-tubing to pump fluid from the well into said production tubing; means providing a fluid passage through said pump between said supply tubing and said area; valve means forming part of said pump unit and movable therewith for opening and closing said passage, said valve means including a valve movable between open and closed positions; and movable operating means for said valve having a portion exposed to fluid pressure in said production tubing for moving said valve to said open position in response to a predetermined fluid pressure in said production tubing.

5. A fluid-operated free pump system according to claim 4 wherein the means last defined includes a pistonlike cage for said valve having an end exposed to fluid pressure in said production tubing.

6. In a fluid-operated free pump system, the combination of: a supply tubing and a production tubing set in a well, said production tubing having a housing at the lower end thereof with which said supply tubing communicates; a free pump unit movable through said production tubing into said housing and having a downwardly-facing area thereon, said pump unit being capable of being biased upwardly in said housing by fluid under pressure applied to said area, and said pump unit including a fluidoperated pump which is operable in said housing by operating fluid under pressure supplied thereto through said supply tubing to pump fluid from the well into said production tubing; means providing a fluid passage through said pump between said supply tubing and said area; and valve means forming part of said pump unit for opening and closing said passage therethrough, said valve means including two opposed members, means for biasing one of said opposed members toward the other, a valve adapted to seat on said opposed members to close said passage, and means for moving said valve out of engagement with said opposed members to open said passage.

7. A fluid-operated free pump system.as defined in claim 6 wherein the means last recited includes a pistonlike cage for said valve having an end exposed to fluid pressure in said production tubing, whereby said valve is moved out of engagement with saidopposed members in response to a predetermined pressure in said production tubing.

8. A fluid-operated free pump system as defined in claim 3 wherein the means last recited includes means responsive to a predetermined fluid pressure in said production tubing.

9. In a fluid-operated free pump unit, the combina- '15 tion of: a fluid-operated pump including an upper housing containing a fluid-operated engine section and a pump section actuable by said engine section, said engine and pump sections including engine and pump pistons, said upper housing being provided with an inlet passage communicating with said engine section; a lower housing connected to the lower end of said upper housing, said pump section and said lower housing having a fluid passage therethrough communicating with said inlet passage and the lower end of said fluid passage having an outlet at the exterior of said lower housing; a downwardly facing surface on one of said housings with its greatest lateral dimension above said outlet; and valve 16 means in said lower housing for opening and closing said fluid passage.

References Cited in the file of this patent UNITED STATES PATENTS 1,593,820 Gates July 27, 1926 1,833,778 Fletcher Nov. 24, 1931 1,927,055 Winsor Sept. 19, 1933 2,230,830 Coberly Feb. 4, 1941 2,311,157 Coberly Feb. 16, 1943 2,589,671 Coberly Mar. 18, 1952