US2841086A - Downwell pump - Google Patents

Description

July 1, 1958 R. DElTRlcKsoN 2,841,086

/ I zaA/E July 1, 1958 R. H. DElTRlcKsoN 2,841,086

DowNwELL PUMP Filed May 13, 1955 2 Sheets-Sheet 2 Syvum/vim;

Unite States Patent O DOWNWELL PUMP Roy7 H. Deitrickson, Toledo, ho, assigner to The National Supply Company, Pittsburgh, Pa., a corporation of Pennsylvania Application May 13, 1953, Serial No. 354,690

6 Claims. (Cl. 10S-46) This invention relates to downwell pumps of the type employed particularly in loil wells, which consist of a hydraulic engine `so constructed and designed that it can be inserted into the well to a point near the bottom of the well; a pump which is connected to, associated with and driven by the engine; and valving mechanisms both for controlling the operation of theengine and pump and for admitting production fluid into the pump cylinder and from the pump cylinder to the conduit or piping leading to the surface.

Most oil bearing areas have large amounts of sand, shale and iother highly abrasive particles which may be drawn into such a pump along with the production iluid, and the production iluid itself may be corrosive. As a consequence it is an :objective in the design and construction of a pump intended to be lowered in the well to a pointy closely adjacent the production area or zone, thatY the corrosive and abrasive production fluid be prevented from coming into contact with as much of the pump mechanism as possible.

'It is desirable to prevent the abrasive and corrosive production uid from contacting the rod between the pump and engine pistons and thus to exclude this fluid from the pump cylinder above the pump piston. By maintaining clean fluid in this space at all times, the condition `of these parts can be kept better and the life greatly extended.

'Ihe instant invention has to do with the arrangement and construction of valving means for controlling the in-feed and output of a single action pump driven by a` hydraulic engine to which it is connected, and having'a separate conduit or duct for carrying the production fluid to the surface.

It is the principal object of this inventionto provide a valve arrangement and to modify the construction of the pump itself in accordance therewith in order to prevent production uid from reaching any portion of the` structure except, of course, the standing valve for the production fluid which is located at the bottom of the pump, the operating side of the pump piston, the interior of the pump cylinder on that side of the piston, and a discharge Valve which controls the discharge of production fluid from the operating side of the pump cylinder.

It. is another object of this invention to provide a downwell pump having a bottom discharge valve for the production fluid which is thereby discharged into a chambei` common to both the production fluid and to exhaust power uid; power uid being the uid pumped downwardly to the pump engine from the surface and being, of course,v clean, the point of production fluid discharge being adjacent the bottom of the pump.

lt is another object of this invention to so arrange a downwell pump that the exhaust power iluid is discharged from the pump engine and flows in such a manner and direction that it always prevents the flow of production uid into areas of the structure which it is undesirable that the production iluid should reach.

A further obiect of this invention is to provide a botf. ICC

tom discharge valve for a downwell, single acting pump which 'by reason of its location and organization with the pump structure as a whole can have a port area substantially larger than that of a more conventional traveling discharge valve and thus which provides less resistance to th passage of the production fluid than such a traveling va ve.

Still another object of this invention is to provide a pump construction incorporating a standing valve and a bottom discharge Valve for handling the production uid on 'its way into and out of the pump cylinder the con struction being such that discharge valves may be ganged, i. e., arranged in parallel, to increase the area of the discharge valve ports for the production iluid being discharged from the pump en route to the surface passageway or conduit.

More specific objects and advantages of the invention will be better understood by reference to the specication which follows and to the drawings, in which:

Fig. l is a vertical sectional view of the lower end of a deep well (not showing the outer well casing itself) and illustrating in somewhat diagrammatic and simplified form, the construction of a downwell pump and its production uid valving embodying the invention.

Fig. 2 is an enlarged horizontal sectional view on the line 2-2 of Fig. 1.

Fig. 3 is a fragmentary vertical sectional'view of the lower portion of the structure shown in Fig. l, taken on a plane perpendicular to the plane of Fig. l, and illus trating the valving mechanism at a different point in the cycle of operations.

Fig. 4 is a view similar to Fig. 3 but showing a mul tiplicity of production uid discharge valves arranged to act in parallel.

A deep well such as an oil well has an outer casing (not shown) which is several inches in diameter, say 6 inches or more, and which serves both to prevent the hole from being lled and as a wall for the well.

In a pump of the type with which the structure embodying the invention is preferably employed there are at least two separate pipes or conduits located within the main well casing. In the drawings there is shown an operatingtubing 10 and, adjacent thereto, a parallel conduit 11 of substantially smaller diameter, which leads to the surface. i The tubing 10 also leads to the surface of the ground and in the installation shown has a dual function: (l) to guide the assemblage of the pump engine, pump cylinder and valve mechanism to the bottom of the well and serve as a housing for the assemblage, and (2) to serve as a conduit for leading high pressure working iluid, for example, oil under pressure, to the pump engine.

In the drawings (Fig. l) there is shown a generally cylindrical engine valve housing 12 which is located at the upper end of the pump engine and is packed oif in the operating tubing 10 by an annular packing 13. At the upper` center of the engine valve housing 12 there is located a screened inlet 14 through'which power oil pumped downwardly through the tubing 10 from the surface enters the engine valve housing 12.

The valve mechanism containedfwithin the engine valve housing 12 functions alternately to connect a passageway 15 to the power oil being pumped down from the surface, and toa power oil discharge conduit. The structure of the valving may take any suitable form.

The passageway 15 leads from the valve housing 12 to the upper side of an engine cylinder 17 above an engine piston 18 which reciprocates therein and the duct 16 leads to the bottom of the engine cylinder 17 beneath the engine piston 18. Power oil is constantly supplied to the duct 16, and the dilerential area of the engine piston l18 causes reciprocating` thereof. l

therebeneath is forced upwardly through the duct 16 andV directed by the valving into the top of the engine cylinder.

Fig. l illustrates the engine piston 18 approaching the end of an upward stroke. Under these conditions the power oil in the duct 16, at high pressure, is entering the engine Icylinder 17 beneath the piston 18 and forcing it upwardly. At the same time the valving within the valve housing 12 has connected a passageway 20 from the upper end of the engine cylinder 17 to exhaust power oil ports 19 so that the power oil locatedY above the piston 18 (which previously drove the piston downwardly) is now forced out through the passageway 20 and ports 19 into the annular area surrounding the valve housing 12 within the tubing 10.

The engine piston 18 is connected by a rod 21 which extends through a packing 22 at the bottom of the engine cylinder 17 to a pump piston 23 located within a pump -cylinder 24 that is concentric with and connected to the engine cylinder 17. cylinder 24 a plurality of ports 25 lead from the interior of the pump cylinder 24 above the pump piston 23 to the annular space surrounding the pump cylinder 24 within the tubing 10. The pump piston 23 is in practice made long `and closely fitted to seal the piston within the cylinder 24. Production uid drawn into working side of the pump cylinder 24 beneath the piston 23 during its up stroke is at lower pressure than the contents of the cylinder above the piston 23 and any leakage past the piston tends to cleanse and lubricate the closely fitted parts. During the downstroke the pressures on the two sides of the piston are substantially balanced and there is little tendency for flow past the piston in either direction.

The lower end of the pump cylinder 24 is connected by suitable adapter means generally indicated at 27 to the upper end of a production fluid control valve housing 28 shown in the drawings as being coaxial with the pump cylinder 24 and of diameter larger than the pump cylinder 24. The housing 28 has a cone shaped end 29 which is illustrated as being seated in a cone socket 30 in an end closure 31 of the tubing 10 located at its bottom end. The illustrated construction at the bottom of the tubing and production fluid control valve housing 28 is merely intended to be conventional to seal the annular area around the engine valve housing 12, engine cylinder 17, pump cylinder 24 and control valve housing 28 from the production zone.

The lower end of the housing 28 is axially bored by an intake passageway 32. way 32 a conical seat 33 is provided for a standing ball valve 34. A cage 35 also is employed to prevent the ball valve 34 from being lifted by the inflowing production fluid to an unnecessarily high level.

A bottom discharge valve generally indicated at 36 is positioned between a chamber 37 within the housing 28 and just above the standing valve 34, and the interior of the pump cylinder 24. The discharge valve 36 has a ball 38 which cooperates with a cone seat 39 to seallan axial bore 4t) leading upwardly into an interior chamber 41 of the discharge valve 36. The chamber 41 is closed at its upper end by a generally pot shaped wall 42 and connected through laterally spaced horizontal openings 43 to the annular space surrounding the housing 28.

The chamber 37 below the discharge valve 36 is connected directly to the pump cylinder 24 through a pair of crescent shaped vertically extending passageways 44 (see Fig. 2) located between the walls 42 of the chamber 41 and the outer wall of the housing 28. The passageways 44 are not connected directly to the chamber 41 At the upper end of the pumpk At the upper end of the passagei 4 except through the bore 40 which is closed by the ball 38 during the pump upstroke as shown in Fig. l.

When the pump piston 23 is moving upwardly, as in Fig. l, production uid enters the passageway 32, displaces the standing ball valve 34 upwardly as shown, ows through the chamber 37 and the two vertically extending passageways 44 into the lower end of the pump cylinder 24. The pressure on the ball 38 from the head of production fluid extending to the surface in the conduit 11 is sufficiently high so as to positively hold the ball 38 in its seat 39 during this upstroke of the pump piston 23. In Fig. l broken line arrows are drawn from the chamber 37 below the bottom discharge valve 36 to the bottom of the pump cylinder 24 to indicate the passage of oil through the crescent shaped passageways 44.

When the engine piston 18 and the pump piston 23 reach the top of their stroke, the valving within the valve housing 12 reverses the ow of power uid as described above and drives the engine piston 18 and pump piston 23 downwardly as shown in Fig. 3. The plane of section of Fig. 3 is rotated 90 on the axis of the pump to reveal the continuity of the passageways 44 between the chamber 37 above the discharge ball valve 38 and the lower end of the pump cylinder 24.

In Fig. 3 the pump piston 23 is shown as approaching the lower end of the pump cylinder 24. Production fluid which had been drawn into the lower side of the pump cylinder 24 at a previous upstroke of the pump piston 23 is indicated by arrows as being forced downwardly through the passageways 44 into the chamber 37 where its pressure seats the standing ball valve 38 and the tluid flows upwardly through the bore 40 displacing the ball 38 and into the chamber 41 and out through the openings 43 to the annular area between the exterior of the housing 28 and the tubing 10.

It will be observed by comparing the arrows extending through the ports 25 at the upper end of the pump cylinder 24 that during the pump upstroke as shown in Fig. l, oil above the pump piston 23 is forced out through the ports 25 into the annular space surrounding the pump cylinder 24. Contrarywise, during the downstroke of the pump piston 23 it is necessary for oil to flow through the ports 25 from the annular space surrounding the pump cylinder 24 into the upper side of the pump cylinder 24 above the pump piston 23. As was earlier explained,V during the upstroke of the engine piston 18, the valving in the engine valve housing 12 connects the upper end of the engine cylinder 17 to the discharge ports 19. Therefore, during either the up strokes of the pump piston 23,A spent or exhaust power oil ows downwardly around the engine cylinder 17 in the annular space between the exterior of the engine cylinder 17 and the tubing 10.

During the upstroke of the pump (Fig. l) the uid discharged from above the pump piston 23 blends with fresh exhaust power uid coming down around the engine cylinder 17 and both continue to flow downwardly through the annular space surrounding the pump cylinder 24 and bottom valve housing 28 reaching the connection to the production uid conduit 11.

During this upstroke no production fluid is being forced into the annular space within the tubing 10 and the exhaust power oil moves downwardly carrying any production fluid left in the annular space with it. The level of the interface between the production and exhausted power fluids drops as shown by the bracket labeled Mixing Zone Production and Exhaust Power Oil in Fig. l.

During the downstroke of the pump piston 23 as shown in Fig. 3 oil flows inwardly through the ports 25 into the upper side of the pump cylinder 24 behind the pump piston 23. The exhaust power uid in the annular space around the pump cylinder is available to fill in this space. Because the exhaust power uid is discharged in relatively large quantities and the proportionate volume of the upper side of the pump cylinderv to the volume of the space around it is so small there is always available more than enough clean exhaust power fluid to iill the space in the pump cylinder 24 above the pump piston 23. Therefore, the production fluid being discharged through the opening 43 into the annular space within the tubing is always kept at a level below the ports 25 and none of the corrosive and dirt-bearing production fluid ever rises sufficiently high to enter the ports 25 and the upper side of the pump cylinder 24.

In effect, the interface or level of blending of the clean exhaust power fluid and the dirty production iiuid floats up and down the exterior of the pump cylinder 24 as the production fluid is forced into the annular space by a discharge stroke of the pump and pulled into the interior of the pump from the production zone on an intake stroke.

Because of the extremely high pressures involved in downwell pumps of the type disclosed in the drawings, the diameter of a pump piston such as the pump piston 23 usually is smaller than the diameter of its engine piston 18 in order that the differences in diameter between the two may give the engine a hydraulic advantage over the pump.

Because the diameter of the pump piston 23 is limited l by this and other practical considerations, where a discharge valve is built into the pump piston 23 in the nature of a traveling discharge valve as is conventional in the shallow well pumps, the diameter of its orifice or orifices is limited by the physical sizes of the pump piston and by the necessity for a substantial connecting rod between the pump piston 23 and the engine piston 18.

The instant invention, therefore, separates the discharge valve from the-pump piston 23 and thus the area of the o rices in the discharge valve 36 of the invention in its location can be substantially larger than the diameter of a traveling valve in the pump piston 23.

Fig. 4 illustrates a manner of gauging two or more discharge valves to still further increase the maximum oriiice area of the discharge valve portions of a pump embodying the invention. In Fig. 4 there is shown a section of tubing 45 containing a pair of bottom discharge valves 46 and 47. Each of the discharge valves 46 or 47 is identical with the structure of the bottom discharge valve 36 of Figs. 1 and 2. Each of the discharge valves 46 and 47 has a bottom bore 48 or 49, a center closed chamber 50 or 51, respectively, a ball valve 52 or 53 and openings 54 or 55 leading from the chamber 50 or 51 to an exterior annular space between a valve housing 56 for the valves 46 and 47 and the tubing 45.

The housing 56 has a standing ball valve 57 which cooperates with a concentric seat 58 at its lower end to control an intake bore 59 in a tapered end 60 of the housing 56 which is seated in a socket 61 in a closure member 62 for the tubing 45. A surface conduit 63 is connected to the bottom of the annular space surrounding the housing 56 as in Figs. l and 3.

Each of the bottom discharge valves 46 and 47 has a pair of vertically extending crescent shaped passageways 64 or 65 as the case might be.

The operation of the two bottom discharge valves 46 and 47 is identical to that of the single bottom discharge valve 36 in Figs. l and 3. Two bottom discharge valves doubles the area of the discharge openings (43 in Figs. 1-3; 54, S5 in Fig. 4) and'reduces the velocity of the oil being discharged into the annular space within the tubing lil or 45.

While the invention has been shown in conjunction with a uid operated pump of a particular type, and in conjunction with a speciiic form and disposition of the parts, it should be expressly understood that it is capable of numerous modifications and changes without departing from the scope of the appended claims.

I claim:

l. In a hydraulicallyv actuated downwell pump for a well having a casing and an inner operating tubing of diameter smaller than the Ainner diameter of the casing, in combination, apparatus consisting of a hydraulic engine and a pump and being located near the bottom of the tubing and having a cylindrical housing smaller in diameter than the inner diameter of said tubing, said tubing and said housing defining an annular space surrounding said housing, a seal closing Yoff such annular space from the part of said tubing above said engine and pump, valving mechanism for said engine to admit power oil from said tubing above said seal to said engine and to discharge exhaust power oil therefrom into the annular space below said seal, 'a production fluid and exhaust power oil conduit separate from said tubing and leading from the lower part of such annular space to the surface, production iiuid valving means located below said pump in said tubing and including a standing valve for admitting production uid into said valving means only and a stationary discharge valve for eiectuating discharge of production iluid from said pump into such .annular space only and at a level below said pump during a discharge stroke of said pump and for directing production fluid admitted into said valving means to the lower side of said pump during an intake stroke, the upper side of said pump being in communication with such annular space at a level above the discharge level of said standing discharge valve and at a level substantially above the level of communication between such space and said separate conduit.

2. A hydraulically actuated downwell pump apparatus for a well having a casing and an inner operating tubing of diameter smaller than the inner diameter of the casing, said apparatus comprising a hydraulic engine and a pump actuated thereby that is located near the bottom of said tubing and has a cylindrical housing smaller in diameter than said tubing, said tubing and said housing defining an annular space external of said housing, a seal closing oi such annular space from the part of said tubing above said engine and pump, said engine having valve mechanism for admitting power oil from said tubing above said seal to said pump and for discharging exhaust power oil into such annular space and said pump having a pump cylinder and a piston working therein, said apparatus being characterized by said pump cylinder having constantly open ports above said piston and at its upper end communicating with such annular space and production fluid valve means comprising a housing having an upper chamber in enclosed communication with the bottom of said pump cylinder, a lower chamber having a bottom production fluid intake bore, a standing valve for such intake bore, and a discharge valve between said chambers, said discharge valve having by-pass passageways connecting said chambers and a valve controlled duct leading from said lower chamber to such annular space at a level substantially below the upper end of said pump cylinder, a seal closing olf such annular space from said production iiuid intake bore, and a separate conduit leading to the surface from the lower end of such annular space whereby exhaust power oil flowing in said annular space en route to said separate conduit passes said pump cylinder open ports and thereinto during a downstroke of said pump and is discharged therefrom into such annular space during an upstroke of said pump.

3. The combination of elements defined in claim 2, and at least a second discharge valve acting in series during an intake stroke and in parallel during a discharge stroke of said pump.

4. In a hydraulically actuated downwell pump that is located near the bottom of a well tubing, and that has a tubular cylinder of outside diameter less than the inside diameter of said tubing and a piston reciprocal in said cylinder, the improvement comprising, in combination a seal closing of said tubing above said cylinder, production uid valving means` on the lower end of said cylinder and including a standing valve for admitting production uid into saidcylinder beneath said piston and a stationary discharge valve for discharging production uid from said cylinder into said tubing exteriorly of said cylinder at the lower end thereof, and ,a surface conduit connected to said tubing near the lower end thereof.

5. In a hydraulically actuated downwcll pumping apparatus tha-t is located near the bottom of a well tubing and that has a hydraulic engine actuated by power fluid pumped from the surface, and a pump having a cylinder and a piston reciprocal therein by said engine, the outside diameters of said engine and said pump cylinder being less than the inside diameter of said tubing, the improvement comprising a seal closing off said tubing ,above said engine, in combination, engine valve means for discharging exhaust power uid into said tubing extcriorlyl of said engine at a levely above said pump cylinder, production uid valving means on the lower end of said-"pump cylinder and including a standing valve for admittingproduction, fluid into said cylinder beneath said piston and a stationary discharge valve for discharging production uid from said cylinder into said tubing exteriorly of said cylinder at the lower end thereof, and a surface conduit connected to said tubing near the lower end thereof.

6. Apparatus as set forth in claim 5 having constantly open ports from the upperl end of said pump cylinder above said piston leading to the annular space in said tubing exterior of said cylinder.

References Cited in the le of this patent UNITED STATES PATENTS 1,805,788 Squires May 19, 1931 2,338,903 Coberly Jan. 11, 1944 2,423,111 OLeary July 1, 1947 2,537,410 Howard Jan. 9, 1951

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