Gas equalizer for downhole pump

Abstract

A gas equalizer device for use in conjunction with a reciprocatory pump located downhole in a wellbore. The device of the present invention avoids a condition commonly known in the pumpjack art as "fluid pounding", which is brought about when compressible gases accumulate in the working chamber of the downhole pump. The gas equalizer device of the invention includes a pushrod having a marginal end reciprocatingly enclosed in a slidable manner within a housing which is mounted to the usual traveling valve cage of the downhole pump. The pushrod is alternately moved from an extended into a retracted position each upstroke and downstroke of the pump. The free terminal end of the pushrod is arranged to engage the ball check valve of the traveling valve assembly as the pump commences the downstroke. This unseats the ball, thereby allowing any accumulated gases to escape from the variable pump chamber. This action allows the escaped gases to flow out of the pump and up the tubing string along with the produced fluid and thereby avoids the undesirable gas locking that otherwise may occur.

I claim: 
     
       1. A gas release device for use in conjunction with a downhole pump of the reciprocatory type that includes a traveling valve assembly having a ball type valve element; said gas release device includes only an adaptor means; a cylindrical main body; a piston assembly; and, a pushrod; said adaptor means enables said main body to be attached directly to the traveling valve assembly of the pump, a passageway formed through said main body and along the central longitudinal axis of the pump, said pushrod has a free end which extends into said passageway for engaging the ball of the traveling valve assembly, and an opposed end is directly and rigidly attached to and forms part of said piston assembly; said main body has an upper end opposed to an enlarged lower end formed thereon .Iadd.A Port Sub.Iaddend.;   said piston assembly has an upper cylindrical skirt member which is rigidly attached to said port sub; passageways formed through said port sub through which production fluid flows each downstroke of the pump and thereby reciprocates the piston assembly towards the traveling valve; opposed faces formed by an inwardly directed boss of the cylindrical skirt member and the lower enlarged end of said main body abuttingly engage during each upstroke;   whereby; the free end of said pushrod lifts the ball of the traveling valve each downstroke of the well pump.   
     
     
       2. The gas release device of claim 1 wherein said downhole pump has a traveling plunger and a seat that receives the ball, said traveling valve is mounted on said traveling plunger at a location whereby said ball thereof is lifted from the seat thereof by the free end of the pushrod during each downstroke of the pump. 
     
     
       3. The gas release device of claim 1 wherein said downhole pump includes a traveling barrel; said traveling valve includes a seat against which the ball is received, said traveling valve is mounted on said traveling barrel at a location whereby said ball thereof is lifted from the seat thereof by the free end of said pushrod during each downstroke of the pump. 
     
     
       4. The gas release device of claim 1 wherein the downhole pump has a traveling plunger, and means forming a valve cage which is connected to provide said traveling valve assembly and to provide a mount means for receiving the upper end of said main body of said gas release device. 
     
     
       5. In a well pump for use in a wellbore, said pump having a pump plunger mounted for reciprocating motion respective to a cylindrical pump barrel, means imparting reciprocatory motion between said plunger and barrel, there being a variable chamber formed between the plunger and barrel for producing fluid therethrough; a traveling valve assembly having a caged ball element received against a seat located therein for controlling fluid flow from the variable chamber; and, a stationary valve assembly which is fixed respective to the wellbore for controlling flow into the variable chamber;   said stationary valve is operative on the downstroke to trap fluid in the variable chamber of the pump and said traveling valve is operative on the upstroke to lift fluid towards the surface; the combination with said traveling valve of a gas equalizing device;   said gas equalizing device includes a cylindrical housing having an upper end attached to the lower end of the traveling valve assembly, and a lower end spaced from said upper end, said cylindrical housing has an axial bore which extends longitudinally therethrough; an enlargement formed on the lower marginal end of said cylindrical housing; circumferentially extending opposed shoulders formed on said enlargement;   a piston having a cavity formed at an upper end thereof, confronting circumferentially extending faces formed within said cavity, and arranged for abuttingly engaging the opposed shoulders of said enlargement of said cylindrical housing; whereby said piston is loosely attached to said cylindrical housing and arranged to reciprocate longitudinally respective thereto between the limits provided by said confronting faces and said shoulders, a passageway formed longitudinally through said piston and into said cylindrical housing through which produced fluid can flow;   a pushrod having an upper marginal end portion telescopingly received within the axial bore of the cylindrical housing and a lower end portion rigidly attached to said piston; said piston reciprocates towards and away from the traveling valve on the downstroke and the upstroke; said upper end portion of said pushrod has a terminal end which engages and lifts the traveling ball element from its seat on the downstroke and which is moved free of the traveling ball on the upstroke;   whereby; said pushrod has a free end that lifts the ball of the traveling valve each downstroke of the well pump so that any compressible fluid accumulated within the variable chamber is free to flow from the variable chamber thereof.   
     
     
       6. The combination of claim 5 wherein said well pump has a traveling plunger, said traveling valve is mounted on said traveling plunger at a location whereby said ball thereof is lifted from the seat thereof during each downstroke of the pump in the aforesaid manner. 
     
     
       7. The combination of claim 6 wherein said equalizer device includes an adaptor by which the traveling valve cage provides a mount means by which said equalizer device can be attached thereto. 
     
     
       8. The combination of claim 5 wherein said well pump includes a traveling barrel; said traveling valve is mounted on said traveling barrel at a location whereby said ball thereof is lifted from the seat thereof during each downstroke of the pump in the before described manner. 
     
     
       9. The combination of claim 8 wherein said equalizer device includes an adaptor means connected to the traveling valve assembly which provides a mount means for said device. 
     
     
       10. In an oil well having an artificial lift apparatus that includes a downhole pump of the reciprocating type for lifting fluid to the surface of the ground, said pump having a plunger, a barrel, a variable chamber formed by the plunger and barrel; said plunger being received within said barrel, means imparting reciprocating motion between the plunger and barrel, a standing valve and a traveling valve having a ball and seat for controlling fluid flow through the variable chamber of the pump, the traveling valve includes a valve cage, the combination with said pump of a gas release device; an adaptor connected to the traveling valve cage at the lower end thereof by which said gas release device is mounted to said traveling valve cage; said gas release device has a cylindrical body having one end affixed to said adaptor and an opposed end which extends towards the standing valve; a piston loosely captured by said opposed end of said cylindrical body to thereby mount the piston for limited reciprocating movement respective to said cylindrical body;   a passageway formed through said piston and cylindrical body, and along the central longitudinal axis of the pump barrel through which produced fluid can flow, a pushrod having a free end extending axially along the longitudinal axis of said cylindrical body for engaging the ball of the traveling valve and a fixed end which is attached to said piston whereby said pushrod is reciprocatingly received in a captured manner within said cylindrical body;   stop means within said piston for limiting the reciprocatory motion of the piston respective to the cylindrical body;   said gas release device has only said piston, said cylindrical body, and said pushrod; said piston comprises only a skirt member and a port sub rigidly attached thereto, said port sub having an upper face which forms one said stop means, a second stop means is formed by the upper end of said skirt member; said skirt member has an inwardly directed boss from which a circumferentially extending downwardly directed cylindrical skirt extends, said passageway is formed through said port sub for flow of production fluid directly therethrough and to the traveling valve; said cylindrical body has an outwardly directed enlargement formed at the lower end thereof which is received within the upper end of said piston;   whereby; said piston moves the end of said pushrod into engagement with the ball to thereby lift the ball of the traveling valve each downstroke of the well pump.   
     
     
       11. The combination of claim 10 wherein said traveling valve is mounted respective to said traveling plunger and to said pushrod whereby said ball of said traveling valve is lifted from the seat thereof during each downstroke of the pump, and the end of said pushrod is spaced from said ball of said traveling valve on each upstroke of the plunger. 
     
     
       12. The combination of claim 10 wherein said gas release device is directly attached to said valve cage by said adaptor; said cylindrical body is directly attached to said adaptor. .Iadd. 
     
     
       13.  A gas release device for use in conjunction with a reciprocating well pump that includes a traveling valve assembly having a ball valve, said gas release device comprising: a body member having a passageway formed therethrough and along the central longitudinal axis of the pump, said body member having an upper end and an opposed, enlarged lower end;   adaptor means for attaching said body member to said traveling valve assembly for reciprocal movement therewith; and   a piston assembly comprising an upper cylindrical skirt member extending around said body member and having an inwardly directed boss;   a port sub rigidly attached to said skirt member, said port sub having flow passages formed therethrough for receiving fluid from said well and;   a pushrod extending from said port sub and having a free end which extends into said passagerway;   whereby on upward movement of said traveling valve assembly and said body member, said enlarged end of said body member engages said boss to move said skirt and said port sub upwardly, and on downward movement of said traveling valve and said body member, said traveling valve assembly and said body member move relative to said piston assembly so that said pushrod engages said ball valve to unseat same. .Iaddend. .Iadd.     
     
     
       14.  The gas release device of claim 13 wherein said pump includes a traveling plunger, said traveling valve assembly being mounted on said traveling plunger and having a seat that receives said ball valve at a location whereby said ball valve is lifted from its seat by the free end of said pushrod during each downstroke of said pump. .Iaddend. .Iadd.15. The gas release device of claim 13 wherein said pump includes a traveling barrel, said traveling valve assembly being mounted on said traveling barrel and having a seat that receives said ball valve at a location whereby said ball valve is lifted from its seat by the free end of said 
     
     
        pushrod during each downstroke of said pump. .Iaddend. .Iadd.16.  In a well pump for use in a wellbore, said pump having a pump plunger and a barrel adapted for relative reciprocal movement to define a variable chamber for receiving fluid, a stationary valve assembly which is fixed respective to the wellbore for controlling flow into the chamber a traveling valve assembly having a ball valve for controlling fluid flow from the chamber, the stationary valve assembly being operative on the upstroke of the plunger to permit fluid to enter the chamber and on the downstroke of the plunger to trap fluid in the chamber, the traveling valve being operative on the upstroke of the plunger to retain fluid in the chamber and on the downstroke of the plunger to permit noncompressible fluid to exit the chamber and enter the barrel; wherein the improvement comprises: a body member having an upper end attached to the lower end of said traveling valve assembly, a lower end spaced from said upper end, an axial bore, and an enlargement formed on said lower end and having circumferentially extending opposed shoulders;   a piston having confronting faces defining a cavity and arranged for abuttingly engaging said opposoed shoulders of said enlargement of said body member to attach said piston to said body member and permit relative movement of said body member relative to said piston between the limits provided by said faces and said shoulders, and a longitudinal passageway through which produced fluid from said well can flow into said variable chamber; and   a pushrod having an upper end portion telescopingly received within the axial bore of the body member and a lower end portion attached to said piston,   said body member moving relative to said piston on the downstroke of said plunger so that the upper end of said pushrod lifts said ball valve from its seat so that any compressible fluid accumulated within the variable   
     
     
        chamber exits therefrom and into said barrel. .Iaddend. .Iadd.17.  The improvement of claim 16 further comprising an adaptor for attaching said 
     
     
        body member to said traveling valve. .Iaddend. .Iadd.18.  The improvement of claim 16 wherein said plunger moves relative to said barrel, said traveling valve being mounted on said plunger at a location whereby said ball valve is lifted from said seat during each downstroke of the pump. .Iaddend. .Iadd.19. The improvement of claim 16 wherein said barrel moves relative to said plunger, said traveling valve being mounted on said barrel at a location whereby said ball valve is lifted from said seat 
     
     
        during each downstroke of the pump. .Iaddend. .Iadd.20.  A gas release device for use in connection with a well pump adapted for reciprocal movement in a vertical direction and having a traveling valve assembly including a ball valve, said gas release device comprising: a body member having a vertically extending through passage;   means for connecting said body member to said traveling valve assembly for movement therewith;   a port sub defining passage means for receiving fluid in said well;   a push rod extending through said passage of said body member in a coaxial relationship thereto and between said port sub and said ball valve in an operative relationship thereto:   a cylindrical skirt having an upper end portion extending over said body member in a coaxial telescoping relationship and a lower end portion connected to said port sub; and   first and second flanges formed on the outer surface of said body member and the inner surface of said skirt, respectively, said second flange adapted to engage said first flange for retaining said skirt over said body member upon upward movement of said body member relative to said skirt and permitting downward movement of said body member relative to said port sub on the downstroke of said pump so that said push rod unseats said ball valve to permit fluid flow through said traveling valve   
     
     
        assembly. .Iaddend. .Iadd.21.  The gas release device of claim 20 wherein said port sub and said skirt permit said downward movement of said body member relative thereto by inertia and by the fluid pressure differential created by said fluid flowing through said passage means of said port sub. 
     
     
        .Iaddend. .Iadd.22.  The gas release device of claim 20 further comprising cooperating threads formed on the lower end portion of said skirt and said port sub to secure said port sub to said skirt. .Iaddend. .Iadd.23. The gas release device of claim 20 wherein one end of said push rod is connected to said port sub and the other end of said push rod is adapted to engage said ball valve upon said downward movement of said body member. .Iaddend. .Iadd.24. The gas release device of claim 20 whereby, upon downward movement of said pump, compressible fluid from said well and below said port sub passes, via said passage in said port sub, into and through said body member and said traveling valve assembly. .Iaddend. 
     
     
        .Iadd.25.  A gas release device for use in connection with a well pump adapted for reciprocal movement in a vertical direction and having a traveling valve assembly including a ball valve for controlling the flow of fluid through a flow passage, said gas release device comprising: a body member having a vertically extending through passage;   means for connecting said body member to said traveling valve assembly for movement therewith;   a port sub defining passage means for receiving fluid in said well, said passage means having a diameter less than the diameter of said flow passage to create a pressure differential across said port sub;   a push rod extending through said passage of said body member in a coaxial relation to said body member and between said port sub and said ball valve in an operative relationship thereto; and   a cylindrical skirt having an upper end portion extending over said body member in a coaxial telescoping relationship, said port sub being connected to the lower end portion of said skirt;   said fluid pressure differential permitting downward movement of said traveling valve assembly relative to said port sub on the downstroke of said pump so that said push rod unseats said ball valve to permit fluid   
     
     
        flow through said flow passage. .Iaddend. .Iadd.26.  The gas release device of claim 25 wherein said push rod is connected to said port sub. .Iaddend. .Iadd.27. The gas release device of claim 25 further comprising means for retaining said skirt over said body member upon upward movement 
     
     
        of said body member relative to said skirt. .Iaddend. .Iadd.28.  The gas release device of claim 25 further comprising cooperating threads formed on the lower end portion of said skirt and said port sub to secure said port sub to said skirt. .Iaddend. .Iadd.29. The gas release device of claim 25 whereby, upon downward movement of said pump, compressible fluid from said well and below said port sub passes, via said passage means of said port sub, into and through said passage of said body member and into and through said flow passage. .Iaddend.