Patent Grant
10364658
Not applicable.
Not applicable.
Not applicable.
1. Field of the Invention
The present invention relates to downhole pumps. More particularly, the present invention relates to rod-type pumps in which a plunger is used so as to draw fluids through a standing valve and pass the fluids through a traveling valve so as to form a fluid column within the production tubing. More particularly, the present invention relates to downhole pumps in which the traveling valve is controlled during the movement of the plunger so as to facilitate the equalization of pressures within the production tubing while, at the same time, effectively removing sand accumulations from within the production tubing, within the barrel, and within the plunger.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
Artificial lift refers to the use of an artificial means to increase the flow of fluids, such as crude oil, gas or water, from a production well. Generally, this is achieved by the use of a mechanical device inside the well (known as a pump) or by decreasing the weight of the hydrostatic column by injecting gas into the liquid some distance down the well. Artificial lift is needed in wells when there is insufficient pressure in the reservoir to lift the produce fluids to the surface, but often is used in naturally flowing wells to increase the flow rate above what would flow naturally. The produced fluid can be oil, water, or a mix of oil and water, along with produced fluids having some amount of gas.
Conventional oil and gas wells include a cased wellbore with a tubing string extending down to the hydrocarbon bearing formation. The casing is perforated at the production level to permit the hydrocarbons to flow into the casing and the bottom of the tubing is generally open to permit the hydrocarbons to flow into the tubing and up to the surface. Oftentimes, there is insufficient pressure in a formation to cause oil and other liquids and gases to readily flow to the surface. It therefore becomes necessary to install the artificial lift system so as to pump the fluids to the surface.
One of the most common types of artificial lift systems is a rod pump. This type of pump is positioned in the well at the level of the fluids to be removed and is mechanically driven by a series of rods connecting the pump to a pumping unit at the surface. These rod pumps include the simple combination of a cylinder or barrel with a piston or plunger and a suitable intake valve and a discharge valve. The intake valve is often referred to as a “standing valve” and the discharge valve is often referred to as a “traveling valve”.
Two of the more common types of rod pumps are the tubing pump in which the pump barrel is attached directly to the tubing and is lowered to the bottom of the well as the tubing is run into the well. The plunger is attached to the bottom of the sucker rod that is positioned within the pump barrel. The intake valve is positioned at the bottom of the pump barrel and the traveling valve is positioned on the plunger. The second type of pump is often referred to as an insert pump and the entire assembly is attached to the bottom of the sucker rod. The barrel is held in place by special seating nipple or other device positioned within the tubing. This type of pump has the advantage that it can more easily be removed for repair or replacement than a tubing pump.
The operation of a rod pump is relatively simple. The plunger reciprocates up-and-down in the barrel under the force of the sucker rod. During the upstroke, the traveling valve is closed and the fluid above the plunger is lifted to the surface by the plunger and the sucker rod. At the same time, the standing valve is open so as to allow fluids to flow into and fill the now-evacuated barrel. On the downstroke, the standing valve is closed so as to trap the fluids in the barrel. The traveling valve is opened allowing the compressed fluids to flow through the plunger so that they can be lifted during the subsequent cycle.
While rod pumps have been in use for decades and have proven to be economical and reliable, they still experience certain shortcomings and problems. Some of these problems are associated with valves which are generally of the ball-and-seat variety. This type of valve is opened and closed by pressure differentials across the valve.
One problem that is often encountered is referred to as gas lock. This occurs when there is a substantial amount of gas that flows into the pump with the liquid. Because of the high compressibility of the gas, insufficient pressure is generated during the downstroke of the pump to open the traveling valve against the hydrostatic pressure of the fluid in the production tubing. Accordingly, the pump can repeatedly cycle without any fluid being lifted to the surface.
Fluid pound is another problem that is often encountered. If the barrel is only partially filled with liquid, the plunger forcefully encounters the liquid level part way through the downstroke so as to cause severe stress to be placed on the pump. Pump-off damage often occurs when the barrel is not completely filled with fluid. Damage occurs in the wall of the working barrel due to overheating of the pump which is caused by the absence of fluid to carry away the heat carried by friction in the pump. Additionally, fluid pound can cause a whipping action of the sucker rod so as to cause potential damage to the production tubing and damage to the sucker rod.
During the production of the formation fluid, mineral particles, often referred to as sand, may be swept into the flow path. The sand may erode production components, such as the downhole pump or sucker rod pump, the control valves on the surface, the ball-and-seat arrangement of the standing valve, etc. in the flow path. When substantial quantities of sand are carried along as oil and/or gas is removed from a formation, the sand can eventually plug the openings in the interior of the tubing by which the hydrocarbon production is withdrawn to the earth's surface. It is not uncommon for the pump itself to stick and/or the barrel to stick as a result of sand or other particulate matter becoming caught between the barrel and the plunger. The tolerances between the barrel and the plunger are close so as to effect a seal between the plunger and the barrel. If sand lodges therebetween, either the plunger or the barrel will be cut or the plunger sticks in the barrel. The structure of such pumps makes them particularly prone to such damage because such pumps rely on a seal which is formed between the plunger and barrel by the leading edge of the plunger.
Generally, when the pump becomes “sanded in” in the production tubing, a very complicated procedure is required so as to remove the sanded-in components of the well. Typically, the production tubing would have to be removed so as to separate the pump from the tubing and remove the sand accumulation. As such, is important that sand the removed from the interior of the production tubing and from the interior of the barrel so as to prevent these problems from occurring.
Typically, such rod pumps do not operate at very well in association with multi-phase fluids are with gas wells. In multi-phase fluids, there can be a gas and a liquid, such as oil or water. In gas wells, typically, the multi-phase liquid will include gas, water and light oil. Because of the high percentage of gas in such wells, the problems associated with gas locks and/or liquid pounding occur more frequently.
Currently, there is a strong trend toward horizontal or deviated wells. Such rod pumps are not particularly effective in pumping the fluid in such deviated or horizontal wells. This is because the sucker rod will have to travel in a similar pattern to that of the deviated wells. In certain circumstances, the deviated well can have a convoluted or S-shaped configuration. As such, it is very difficult for the rod to effectively reciprocate upwardly and downwardly in such deviated wells. Furthermore, when sucker rods are used in such deviated wells, they can rub against the side of the production tubing so as to eventually perforate the production tubing in areas that are not desired. The frictional contact between the rod in the inner wall of the production tubing can further potentially damage the sucker rod such that the well will need to be repaired by pulling the production tubing and replacing the damaged tubing or by pulling the sucker rod and replacing the damaged section of the sucker rod. Once again, this could lead to an extended period of non-productivity of the well.
In the past, a variety of patents have issued relating to such rod pumps. In particular, U.S. Pat. No. 2,344,786, issued on Mar. 21, 1944 to Patterson et al., describes an anti-pound pump pressure equalizer. This anti-pound pump has a working chamber between the standing and traveling valves. A means is exposed at one side to the working chamber pressure and is yieldable in one direction in accordance with rising pressure in the working chamber during each discharge stroke of the pump. A chamber is formed that is isolated from the rising pressure. The yielding means is positionable during the course of the yielding movement for opening the working chamber of the pump into pressure-equalizing communication with the production column independent of the traveling valve of the pump. A means is provided for returning the yieldable means to an interactive position subsequent to pressure equalization.
U.S. Pat. No. 4,599,051, issued on Jul. 8, 1986 to H. L. Spears, discloses a traveling valve assembly for a fluid pump. This traveling valve assembly includes a ball valve actuator which engages the ball valve during the downstroke of the sucker rod to force the ball open into an open fluid transmitting relationship with respect to the valve seat.
U.S. Pat. No. 4,691,735, issued on Sep. 8, 1987 to J. B. Horton, shows a plunger valve apparatus for an oil well pump. The traveling valve or standing valve for the pump includes a piston which lifts the ball above the valve seat to open the valve and sets the ball back on to the seat to close the valve. The ball is contained within a ball protection shield which prevents uncontrolled movement by the ball inside a middle tube. The piston has openings and the ball protection shield has apertures which allow fluid to flow through the valve without engaging the ball.
U.S. Pat. No. 4,708,597, issued on Nov. 24, 1987 to A. V. Fekete, describes a plunger with a simple retention valve. The fluid pump has a plunger reciprocating within a working cylinder and a standing intake retention valve. The plunger includes a stem having a plug and a stop affixed to it. The plunger also has a body that is slidably engaged to the cylinder and located on the discharge side of the plug and on the intake side of the stop. Upon the upstroke of the plunger, a plug surface engages with a sealed body and therefore pumps the fluid before it. Meanwhile, fluid flows in behind the plunger through the standing intake retention valve. On the downstroke, the plug disengages from the body so as to allow fluid to flow noncompressibly past the plunger.
U.S. Pat. No. 4,741,679, issued on May 3, 1988 to D. L. Blassingame, discloses an oil well traveling valve for a sucker rod-operated oil pump. This traveling valve includes a fluid outlet ported pump head connecting inner and outer sleeves with the upper end of a working barrel for reciprocating the working barrel. A valve is tethered within the inner sleeve in a manner ensuring separation of the valve from its seat for opening the pump fluid passageway and exhausting gas from the pump bore with each complete sucker rod stroke.
U.S. Pat. No. 4,781,543, issued on Nov. 1, 1988 to G. M. Sommer, teaches an artificial lift system for oil wells in which oil is recovered from an underground formation more efficiently by the use of a subsurface power piston that reciprocates a subsurface pump. A series of connecting rods connects the power piston to the subsurface pump. The subsurface power piston is driven upwardly by a surface-mounted hydraulic actuation system. The distance between the subsurface pump and the power piston is set so that pressure at the depths of the power piston and pump closely counterbalance the weight of the sucker rod string at all positions of the stroke with a slight down bias.
U.S. Pat. No. 4,781,547, issued on Nov. 1, 1988 to R. D. Madden, shows a gas equalizer for a downhole pump. This gas equalizer device is intended to avoid the fluid pounding condition. The gas equalizer device 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 push rod is alternately moved from an extended to a retracted position each upstroke and downstroke of the pump. The free terminal end of the push rod is arranged to engage the ball check valve of the traveling valve assembly as the pump commences the downstroke. This unseats the ball so as to allow any accumulated gases to escape from the variable pump chamber. The escape gases flow out of the pump and up the tubing string along with the produced fluid.
U.S. Pat. No. 4,867,242, issued on Sep. 19, 1989 to G. E. Hart, discloses a method and apparatus for breaking a gas lock in an oil well pump. This apparatus includes a stationary barrel with a standing valve on the bottom, a reciprocating piston in the barrel with a traveling valve on the bottom of the piston, and an unseating rod positioned above the standing valve and adapted to protrude into the traveling valve to unseat the ball closure thereof near the bottom extremity of the downstroke of the piston.
U.S. Pat. No. 4,907,953, issued on Mar. 13, 1992 Hebert et al., teaches a locking gas equalizer for use with a subsurface pump for lifting fluids having a high gas content. A mechanical lifting piston and rod are slidably mounted beneath the check valve in the traveling pump assembly. When the pump reaches the bottom of its downstroke, the piston raises the rod and unseats the check valve. As the pump cycle reverses at the top of the stroke, the inertia of the piston also causes the rod to be raised for unseating the check valve and allowing a small amount of fluid to drop into the pump chamber. As a result, gas pressure within the pump chamber volume is positively equalized to prevent gas lock of the pumping action.
U.S. Pat. No. 5,407,333, issued on Apr. 18, 1995 to C. T. Lambright, discloses a rod-driven downhole pump. The pump includes a traveling barrel contained within a pump housing, a central pump rod extending axially within the barrel, a valve ball located at the lower end of the pump rod, and a valve seat near the barrel lower end. The pump rod includes a rod shoulder for engaging the upper end of the barrel. The barrel contains annular passageways for the flow of fluid through the barrel. The pump rod is reciprocable within the barrel and the barrel is reciprocable within the pump housing. The downward stroke of the pump rod causes the rod shoulder to engage the barrel's upper end and concurrently displaces the ball valve below the valve seat so as to allow environmental fluid to flow through the annular passageways of the barrel. On the upstroke of the pump rod, the valve ball engages the valve seat and pushes the pump barrel upwardly within the pump housing.
U.S. Pat. No. 5,139,398, issued on Aug. 18, 1992 to T. R. Downing, provides a neutralizer valve for a downhole pump. This neutralizer valve is for use in conjunction with one or more reciprocating pumps. The neutralizer valve takes the place of a regular traveling valve and a rod pump. The neutralizer valve includes a drag plunger for passing a crude and natural gas mix therethrough on a downstroke of the tubing string. The neutralizer valve includes a guide barrel that is connected into the rod pump plunger and contains a ported seal stem that is arranged to move up-and-down therein. The ported seal stem includes a keyed rod at its upper end that is to travel up-and-down in a keyway that is formed through a ported disc which is arranged across the guide barrel interior. On an up-stroke of the rod tubing string, the valve closes so as to create a void between it and a standing valve of a downhole pump. On the downstroke, the stem collar valve face is moved off the seat so as to open the valve to allow a fluid to flow therethrough.
U.S. Pat. No. 5,141,411, issued on Aug. 25, 1992 to J. H. Klaeger, discloses a center-anchored rod-actuated pump which is particularly useful in deep and/or low-pressure stripper wells. The pump includes a traveling valve and a standing valve. The traveling valve is provided with a valve member which includes a downwardly extending stem which terminates in a lower bearing surface. The standing valve is provided with a valve member having an upper bearing surface. As the plunger of the pump is reciprocated, the lower bearing surface of the valve member of the traveling valve mounted therein contacts the upper bearing surface of the valve member of the standing valve when the plunger is near the maximum extent of downward travel so as to force the traveling valve open and/or force the standing valve closed depending upon fluid pressure conditions and whether the standing valve is stuck open.
U.S. Pat. No. 5,628,624, issued on May 13, 1997 to J. A. Nelson, discloses an assembly for unseating a seated traveling valve ball. The assembly includes a tubular member having therein a piston with an actuator for engaging the ball. Mechanical advantage is provided either by providing a sealing area of the piston that is greater than the sealing area of the seat valve and/or by providing an engaging member suitable to strike the seated ball asymmetrically with respect to the vertical axis through the center line of the ball.
U.S. Pat. No. 5,829,952, issued on Nov. 3, 1998 to D. W. Shadden, provides a reversible valve ball assembly for use in a downhole pump check valve. The reversible valve ball can be removed, inverted and reinserted into the check valve to provide a new valve ball sealing surface. The reversal of the valve ball is performed after the original valve ball sealing surface has worn and deteriorated so that it can no longer seat properly to form a seal between the valve ball surface and a valve seat. A set of irregularly-shaped valve ball guide arms are provided which rotate within valve guide apertures to provide a clean action between the valve guide apertures and the valve ball arms to prevent accumulation of debris. An elongated gas-breaker fin is provided so as to prevent a gas lock. The gas-breaker fin enables a reduced vertical length for the valve ball arms so that a reversible symmetric valve ball assembly can be utilized.
U.S. Pat. No. 6,481,987, issued on Nov. 19, 2002 to M. B. Ford, discloses an improved traveling valve that has a valve positioned on a seal stem so that the ball is reliably centered when seated on the valve seat. The traveling valve is constructed so that a lower portion of the valve rotates during pumping so as to impart rotational movement of the fluid passing therethrough. The rotational movement is caused by angled channels in an interior portion of a vane and the rotator positioned at the bottom of the traveling valve so as to work in combination with the angled channels in the seal stem.
U.S. Pat. No. 7,051,813, issued on May 30, 2006 to Hayes et al., shows a pass-through valve and stab tool. This tool allows periodic access through one or more one-way of valves installed in a fluid flow stream. Fluid can flow through the bypassed valves or through the tools used to bypass the valves in the manner of a reciprocating production pump. A stab tool cooperates with a valve to unseat a ball from a ball seat so as to bypass the ball and pass through the ball seat. The stab tool is conveyed by tubing for discharge of fluid through ports in the stab tool. A rod is installed within a pump between a reciprocating uphole valve and a downhole valve is arranged so that when the pump is closed, the stab tool at the rod's lower and passes through the downhole valve and a projection at the rod's upper end passes through the uphole valve such that the pump is partially closed.
U.S. Pat. No. 7,878,767, issued on Feb. 1, 2011 to M. B. Ford, describes a cyclonic debris-removing valve. The ball valve is capable of transitioning between an open position and a closed position. The ball valve includes a hydraulic piston, a containment union, a ported stem, a containment cage, and a drag plunger. The ball valve is adapted to regulate the flow of fluid northward through the valve. During a pump downstroke, fluid enters the drag plunger, moves northward through the containment cage and into the interior of the ported stem, exits the interior of the ported stem and enters a plurality of angled vanes so as to impart cyclonic motion on fluid passing northward therethrough so as to assist in the removal of debris. During the downstroke, a pedestal portion of the hydraulic piston unseats the ball from the seat.
U.S. Patent Application Publication No. 2005/0053503, published a Mar. 10, 2005 to R. D. Gallant, describes an anti-gas-lock pumping system. The pump is designed such that any gas present in the fluid that is pumped is completely displaced from the pumping chamber with each downstroke of a pump plunger.
U.S. Patent Application Publication No. 2013/0025846, published on Jan. 31, 2013 to G. Scott, teaches an apparatus for use with the traveling valve assembly of a downhole pump for releasing gas and so as to prevent gas locks. The apparatus comprises a piston slidably disposed within a cylindrical housing. The piston is driven by an attached plunger element. On the downstroke of the pump, the piston protrudes through an end of the cylindrical housing so as to engage and open the adjacent valve. On the upstroke of the pump, the piston retracts into the cylindrical housing so as to disengage from the valve and to allow the valve to close. Fluid flows along the outer surface of the apparatus by means of fluid ports connected by defined fluid passages.
U.S. Pat. No. Re 33,136, reissued on Feb. 13, 1990 R. D. Madden, describes a gas equalizer device for use in conjunction with a reciprocating pump located downhole within a wellbore. The gas equalizer device 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 push rod is alternately moved from an extended position to a retracted position on each upstroke and each 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 so as to allow any accumulated gases to escape from the variable pump chamber.
It is an object of the present invention provide a downhole pump system with higher system efficiencies.
It is another object of the present invention to provide a downhole pump system that has greater operational capabilities.
It is another object of the present invention to provide a downhole pump system that has lower operating costs.
It is still another object of the present invention to provide a downhole pump system that maximizes hydrocarbon production.
It is another object of the present invention to provide a downhole pump system that avoids gas locks.
It is a further object of the present invention to provide a downhole pump system that operates in horizontal and/or highly-deviated production tubing.
It is another object of the present invention to provide a downhole pump system that is able to able to produce at low rates and at high pressures.
It is another object of the present invention to provide a downhole pump system that is operable at extended depths and high temperatures.
It is still another object of the present invention to provide a downhole pump system that effectively remove solids from the fluid during the production.
It is another object of the present invention provide a downhole pump system that provides extended runtime.
It is still a further object of the present invention to provide a downhole pump system that has reduced sensitivity to solids plugging.
It is another object of the present invention to provide a downhole pump system that reduces rod buckling stress and reduces the problems associated with deviated rods.
It is still another object of the present invention to provide a downhole pump system that maximizes pump fillage.
It is still another object of the present invention provide a downhole pump system that avoids ball dance damage.
It is still a further object of the present invention to provide a downhole pump system that minimizes fluid pound and the problems resulting from fluid pound.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.
The present invention is a fluid pump for an artificial lift system. The fluid pump includes a barrel, a standing valve located at a lower end of the barrel, a plunger reciprocatingly mounted within the barrel, and a traveling valve incorporated within the interior of the plunger so as to control fluid flow through the plunger.
The barrel of the present invention includes a first wide inner diameter section, a second wide inner diameter section, and a reduced inner diameter section between the first wide inner diameter section and the second wide inner diameter section. The barrel includes an opening at the top thereof and an opening at the bottom thereof.
The standing valve is positioned within the barrel at the opening at the bottom of the barrel. The standing valve is movable between an open position and a closed position. The open position allows fluid to flow into an interior of the barrel. In particular, the bottom end of the barrel includes an aperture formed therein. The standing valve has a flat surface at the top thereof located within the interior of the barrel and has a stem extending downwardly from this flat surface. The stem extends through the aperture at the bottom of the barrel.
The plunger includes a wide diameter section and a narrow diameter section. The narrow diameter section is located above the wide diameter section. A first aperture is provided at the top of the plunger so as to extend into an interior of the plunger. A second aperture opens to the sidewall of the plunger so as to open to the interior of the plunger. A channel extends longitudinally so as to open at the bottom of the plunger from a central chamber located within the interior of the plunger. A rod extends from the top of the plunger. This rod can be connected to a sucker rod associated with the pump mechanism. A first shoulder is formed in the central chamber of the plunger and located below the first aperture and above the second aperture. This first shoulder provides a seating area for the traveling valve.
The traveling valve has a head portion having a diameter suitable for seating on the shoulder of the plunger. The traveling valve includes a body that is connected to the head portion. The body is adapted for slidable movement within the interior of the plunger. The body has a fluid passing channel therein so as to open at an exterior of the body. The body also includes a tubular member having an outer diameter less than an inner diameter of the channel of the plunger. As such, this tubular member can be slidable within the channel. A spring is mounted to the plunger and to the traveling valve so as to urge the traveling valve into sealing relationship with the shoulder of the plunger.
An upper pipe can be connected to the top of the barrel. The upper pipe can be secured, by conventional means, to the production tubing.
The traveling valve is movable to a first position in which the fluid above the plunger passes through the first aperture into an interior of the plunger, passes through the fluid-passing channel of the body, and passes through the tubular member so as to pass into the interior of the barrel below the bottom of the plunger. As such, the serves to equalize pressure of the fluid above the plunger and below the plunger. The traveling valve is also movable to a position such that the narrow inner diameter section of the barrel bears against the wide diameter portion of the plunger such that a compression chamber is formed in an area between the narrow diameter section of the plunger and the wide inner diameter section of the barrel. An upper end of the narrow diameter section of the plunger is in sealing relationship with the inner diameter of the upper pipe. The compressed fluid in the compression chamber flows through the second aperture of the plunger so as to urge the traveling valve upwardly and pass the compressed fluid through the interior of the plunger below the traveling valve and through the tubular member so as to flush sand therefrom.
The traveling valve is also movable to an upper position such that the wide diameter section of the plunger is spaced from the narrow inner diameter section of the barrel such that the compressed fluid from the compression chamber is released toward the interior of the barrel and toward the bottom of the plunger so as to flush sand from the inner wall of the barrel and the outer wall of the plunger. A bottom of the tubular member is spaced from the channel of the barrel such that compressed fluid from the compression chamber passes through the channel of the barrel so as to flush sand from the channel of the barrel. In this arrangement, the standing valve is unseated.
The plunger is also movable to a lower position at the bottom of the stroke such that the traveling valve is in seated relationship with the shoulder of the plunger such that the fluid above the plunger can flow through a space between the narrow diameter section of the plunger and the second wide inner diameter section of the barrel so as to equalize pressures above and below the plunger. The tubular member of the traveling valve is in sealing relationship with the tubular member of the barrel.
This foregoing Section is intended describe, with particularity, the preferred embodiments of the present invention. It is understood that modifications to these preferred embodiments can be made within the scope of the appended claims. As such, the Section should not be construed, in any way, as limiting of the broad scope of the present invention. The present invention should only be limited by the following claims and their legal equivalents.
Referring to
A horsehead 30 is mounted to an opposite end of the walking beam 12. A bridle 32 extends downwardly from the horsehead 30 and is joined to a polished rod 34. Polished rod 34 extends through stuffing box 36 and downwardly into the well 38. There is a tee 40 at the top of the well 38 which allows oil and gas to be transmitted from the interior of the production tubing 42 located within the well 38.
A downhole pump 44 will be located at the end of a sucker rod 46. Sucker rod 46 extends through the interior of the production tubing 42. As a result, the reciprocating movement of the walking beam 12 will cause the sucker rod 46 to move upwardly and downwardly and will cause the downhole pump 44 to move upwardly and downwardly so as to draw fluids through the production tubing 42. It can be seen that the downhole pump 44 is located within an oil-bearing zone 48. Various perforations are formed in the casing 50 in the area of the production zone 48 so as to allow fluids to pass into the casing 50 and around the production tubing 42. Ultimately, the accumulation of fluids within the annulus between the production tubing 46 and the casing 50 will flow so as to be drawn by the downhole pump upwardly for discharge at the surface.
The barrel 52 includes a first wide interior diameter section 66, a second wide interior diameter section 68 and a reduced interior diameter section 70. The reduced interior diameter 70 is located between the first wide interior diameter section 66 and the second wide interior diameter section 68. The barrel 52 includes an opening at the top thereof and an opening 72 at the bottom thereof. In particular, the barrel 52 has a narrowed bottom end 74 that will define the opening 72.
The standing valve 54 is located at the bottom opening 72. In normal use, the standing valve 54 will be movable between an open position and a closed position. In the open position (as shown in
The plunger 56 includes a wide diameter section 82 and a narrow diameter section 84. The narrow diameter section 84 is located above the wide diameter section 82. A first aperture 86 is formed at the top of the plunger 56. A second aperture 88 is formed through the sidewall of the plunger 56 so as to open into a volume 90 located within the interior of the plunger 56. A channel 92 has one end opening to the interior 90 of the plunger 56 and opposite end opening at the bottom 80 of the plunger 56. The channel 92 extends longitudinally through the plunger 56. A rod 96 is connected to the top of the plunger 56 and extends upwardly. This rod 96 can be connected to the sucker rod 46 of the pumping system. The plunger 56 also includes a shoulder 98 at a bottom of the interior 90 and generally above the wide diameter section 82. The seating area for the traveling valve 58 (as seen in
The traveling valve 58 includes a head 100 having a diameter suitable for seating on the shoulder 120 (as shown in
In
Importantly, the compressed fluid within the compression chamber 110 can flow only through the second aperture 88. This force urges the body 102 of the traveling valve 58 upwardly so as to unseat the head 58 from the interior of the plunger 56. As a result, fluids located within the interior 62 of the upper pipe 64 can flow through the first aperture 86 (as indicated by the arrows), around the head 100 of the traveling valve 58, through the channel 104 of the traveling valve 58 and downwardly through the tubular member 106. These fluids will then flow downwardly through the channel 92 in the plunger 56 so as to enter the interior 90 of the barrel 52. The compressed fluid from the compression chamber 110 will also flow through the second aperture 88 and downwardly through the space between the tubular member 106 of the traveling valve 58 and within the channel 92 of the plunger 56. The flow of the fluid serves to equalize pressure between the top and bottom of the plunger 56. The compressed fluid passing therethrough can serve to remove debris, such as sand, scale, calcium carbonate, iron sulfide, and other materials from the working surfaces associated with the barrel 56. As such, the present invention effectively provides a “flushing action” so as to remove the sand, while, at the same time, equalizing pressures within the barrel 52. Also, the friction movement in the fluid participates in this flashing action. The contribution of the compressed volume and the friction movement will depend on the composition of the fluid (i.e. the gas quantity).
In
Following this downstroke position, the piston 56 can be moved upwardly so as to once again create the compression chamber and to carry out the movement of fluids in the manner described herein before in association with
In particular,
The fluid pump apparatus 300, shown in
As with the previous embodiment, it can be seen that there is a rod 316 that extends upwardly from the plunger 308. An aperture 318 extends so as to open to the interior of the barrel 310 in the above plunger area 312. A spring 320 is mounted in the central chamber 322 so as to bear against the interior of the plunger 308 and also to bear against the traveling valve 304. Another aperture 324 opens through the wall of the plunger 308 so as to communicate with the channel 326 that extends longitudinally within the plunger 308. Another channel 328 communicates between the central chamber 322 and the chamber 330. In
In the alternative embodiment of the present invention, the closure of the standing valve 502 is delayed during the end of the upstroke phase of the fluid pump apparatus 500, as is shown in
The delay of closing of the standing valve 502 will depend on the balance between the spring force 506, the passage area thru standing valve 502, and the passage area through traveling valve (via port 508). The minimum pressure required in “UP” chamber 510 to close the valve 502 corresponds to the force 504 applied on section 512 of standing valve 502. So, once the flow through the traveling valve is great enough big to create the minimum pressure, the standing valve will close and will be fully closed before the end of the upstroke phase. Note that the return spring characteristics will have to be defined according depth level range of the well.
The spring-loaded standing valve 502 shown in
The present invention provides a downhole pump that has a fixed barrel with a reciprocating plunger moving therein by way of a rod string. A standing valve is located at the bottom of the barrel and a traveling valve is at the plunger. The barrel chamber is provided between the traveling valve and the standing valve and expands during an upstroke movement and contracts during the downstroke movement. A hydraulic actuation system is provided to open the traveling valve before the end of the upstroke in order to make communication between the barrel chamber and the fluid column. When the traveling valve is open, the weight of the column ensures the pressure balancing instantaneously regardless of the gas volume within the barrel chamber. This occurs through the use of the opening traveling valve. Gas within the barrel chamber can vent through the traveling valve in order to prevent gas locks. The immediate balancing pressure above and below the plunger allows the ability to minimize stress on the sucker rods in order to avoid the fluid pounding effect. As such, damage to the rod string is effectively prevented. As a result, the present invention reduces the need to ever pull the rod string. This avoids the very expensive, labor-intensive, and equipment-intensive procedures. It also serves to avoid lost production. The present invention effectively provides a mechanism whereby any solids present within the pump can be discharged so as to avoid a sand locking of the piston or damage to the components of the plunger and barrel.
The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the illustrated construction can be made within the scope of the present claims without departing from the true spirit of the invention. The present invention should only be limited by the following claims and their legal equivalents.
The present application claims priority from U.S. Provisional Patent Application Ser. No. 62/218,087, filed on Sep. 14, 2015, and entitled “Downhole Pump with Controlled Traveling Valve”.
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| Number | Date | Country | |
|---|---|---|---|
| 20170096884 A1 | Apr 2017 | US |
| Number | Date | Country | |
|---|---|---|---|
| 62218087 | Sep 2015 | US |
