Downhole jet pump
A downhole jet pump wherein pressurized gas from an outside portion of a string of tubing is directed through a nozzle having a venturi which causes fluids to be sucked from an outside portion of the string of tubing and ejected through an inside portion of the sting of tubing.
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This application claims priority to and the benefit of the filing of U.S. Provisional Patent Application Ser. No. 60/645,806, entitled “Downhole Well Pump”, filed on Jan. 21, 2005, and the specification and drawings thereof are incorporated herein by reference.
FIELD OF THE INVENTIONThe present invention relates generally to a pump for removing fluids from a cased hole, i.e. a well bore. More particularly, the present invention relates to a novel downhole, gas-driven pump, with no moving parts, particularly suitable for removing fluids from hydrocarbon producing wells.
BACKGROUND OF THE INVENTIONIncreasing production demands and the need to extend the economic life of oil and gas wells have long posed a variety of problems. For example, as natural gas is produced, from a reservoir, the pressure within the reservoir decreases over time and some fluids that are entrained in the gas stream with higher pressures, break out due to lower reservoir pressures, and build up within the well bore. In time, the bottom hole pressure will decrease to such an extent that the pressure will be insufficient to lift the accumulated fluids to the surface. In turn, the hydrostatic pressure of the accumulated fluids causes the natural gas produced from the “pay zone” to become substantially reduced or maybe even completely static, reducing or preventing the gases/fluids from flowing into the perforated cased hole. In such cases, the well bore may log off and possibly be plugged prematurely for economic reasons.
The oil and gas industry has used various methods to lift fluids from well bores. The most common method is the use of a pump jack (reciprocating pump), but pump jack systems have given rise to additional problems. Pump jack systems require a large mass of steel to be installed on the surface and comprise several moving parts, including counter balance weights, which pose a significant risk of serious injury to operators. Additionally, this type of artificial lift system causes wear to well tubing due to pumping rods that are constantly moving up and down inside the tubing. Consequently, pump jack systems have significant service costs, which negatively impact the economic viability of a well.
Another known system for lifting well fluids is a plunger lift system. The plunger lift system requires bottom hole pressure assistance to raise a piston, which lifts liquids to the surface. Like the pump jack system, the plunger lift system includes numerous supporting equipment elements that must be maintained and replaced regularly to operate effectively. This adds significant costs to the production of hydrocarbons from the well. In addition, plunger lift systems eventually become ineffective due to lower reservoir pressures than are required to lift the piston to the surface to evacuate the built up liquids.
Yet another system for lifting well fluids from a well bore is disclosed in PCT International Application No.: PCT/US02/32462, which is hereby incorporated by reference. In that system gas from the well is used to power a downhole pump. The disclosed pump design uses pressurized gas to rotate impeller or turbine-type blades, which lift well fluids from the well. While this design does not have the above-described drawbacks inherent in the pump jack and plunger lift systems, it still includes moving parts (impeller/turbine blades) which increases the potential for wear and malfunction.
Thus, there is a need for a safe, durable and cost effective pump system that is less susceptible to mechanical failure and that effectively removes liquids from well bores that do not have sufficient bottom hole pressure to lift the liquids to the surface.
BRIEF SUMMARY OF THE INVENTIONThe present invention relates to a downhole jet pump having a plurality of elongated openings disposed circumferentially about a central jet nozzle, the plurality of openings communicable to an outside portion of at least one piece of an inner tubing string, a chamber providing a passageway from said plurality of elongated openings to an inlet of said central jet, said central jet comprising an outlet communicable to an inside of said inner tubing string.
The downhole jet pump can also have a venturi disposed near the outlet of the central jet and/or an outer tubing string disposed between an inner tubing string and a well casing. The venturi can be in fluid communication with an outside of the inner tubing and/or an area between the outer tubing string and well casing. The plurality of elongated openings can be communicable to a backside of a well and/or an annular space between the inner tubing string and the outer tubing string.
The downhole jet pump can also have a diffuser with an opening which is disposed between the central jet outlet and the inside of the inner tubing string. The diffuser opening can have a substantially conical shape.
In an embodiment of the present invention, pressurized gas preferably flows from an outside of the inner tubing string, through the venturi, wherein the venturi causes an area of reduced pressure to be created which in turn draws liquids and/or gasses from an outside of the inner tubing string to an inside of the inner tubing string. In another embodiment of the present invention, pressurized gas flows between an outside of the inner tubing string and an inside of the outer tubing string, through the venturi, wherein the venturi causes an area of reduced pressure to be created which in turn draws liquids and/or gasses from an outside of the outer tubing string to an inside of the inner tubing string.
The jet pump can be comprised of a plurality of subparts which connect to form the jet pump. One or more pins and pin openings can be provided for enabling proper alignment of the subparts. In one embodiment, pressurized gas is provided by a natural formation. In a preferred embodiment, pressurized gas is provided by injecting a pressurized gas between an area between an outer diameter of the inner tubing string and an inner diameter of the outer tubing string.
The present invention can be used on wells of virtually any depth. As such, the inner tubing string as used in the present invention can have virtually any length, including lengths of at least 100 feet, at least 250 feet, and at least 500 feet.
The present invention also relates to a method for removing fluid from a well having the steps of providing a string of casing tubing having at least one opening which is communicable to a hydrocarbon producing formation; providing an second string of tubing disposed within the casing tubing; positioning a jet pump on a terminal portion of the second string of tubing; and allowing a pressurized gas to travel between the casing tubing and the second string of tubing and through the jet pump wherein venturi action causes fluid to be sucked from outside the second string of tubing and ejected through an inner portion of the second string of tubing.
The method can be used to remove fluid buildup from a natural gas producing well. Optionally, in the method, at least one of the openings can include at least one perforation in the casing.
The present invention also relates to a method for removing fluid from a well having the steps of providing a string of casing tubing having at least one opening which is communicable to a hydrocarbon producing formation; providing an outer tubing string disposed within an inside diameter of the casing tubing; providing an inner tubing string disposed within an inside diameter of the outer tubing string; positioning a jet pump on a terminal portion of an element selected from the inner tubing string, the outer tubing string and combinations thereof; and allowing a pressurized gas to travel between an outside diameter of the inner tubing string and an inner diameter of the outer tubing string, through the jet pump wherein venturi action causes fluid to be drawn from an area outside of the outer string of tubing and ejected through an inner portion of the inner string of tubing. The method can be used to remove fluid buildup from a natural gas producing well.
The present invention also relates to a downhole jet pump having a substantially conically-shaped diffuser opening a venturi disposed such that an outflow of the venturi is communicably coupled to an inlet of the diffuser opening, an annulus for the transport of a pressurized gas to the venturi, the annulus comprising at least one central axis disposed substantially parallel with a central axis of the opening, and a liquids inlet disposed at or near a terminal portion of the jet pump which is opposite that of an outlet of the diffuser opening.
The diffuser opening outlet can be communicably coupled to at least one piece of tubing. The liquids inlet can be communicably coupled to a backside of a well. The be a hydrocarbon-producing well, a water well, or the like.
The annulus is communicable to an area between an inner tubing string and an outer tubing string.
Objects, advantages and novel features, and further scope of applicability of the present invention will be set forth in part in the detailed description to follow, taken in conjunction with the accompanying drawings, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGSFor a more complete understanding of the present invention and for further advantages thereof, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:
The term “tubing” as used throughout the specification and claims is intended to include all elongated elements having at least one opening extending the length of said element. As such, the term “tubing” includes any and all pipes, tubes, extruded hollow members, cast hollow members, collars, nipples, reducers, couplers, and the like, as well as combinations and multiples thereof. The term “tubing string” as used throughout the specification and claims is intended to include one or more pieces of tubing.
The present invention is a novel downhole pump for use in the removal of fluids from wells, especially, but not limited to, wells that have insufficient bottom hole pressure to lift the well liquids out of the well bore and to the surface. In its typical use, the pump is disposed downhole in a well adjacent the bottom of the well or the hydrocarbon-producing formation. Referring now to
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When the pump 10 is fully assembled, as depicted in FIGS. IA and 9A-9B, upper flow adapter 200 is connected to pump housing 300, which is connected to the lower flow adapter 400. Any suitable means can be used to connect these components. Most preferably, these components are removably connected, such as by threaded connection.
The assembled pump and the flow of fluids within and about the pump (i.e., the operation of the pump) are depicted in
The motive gas needed to operate the pump can be from any source so long as the pressure and flow of gas is adequate to lift the fluids from the well. In a preferred embodiment of the invention, the pump would be driven by the natural gas produced from the well. In some cases the natural pressure of the gases produced from the well will be sufficient to effectively operate the pump without the need to compress the gas. For many wells the natural gas pressure will be insufficient. In such cases, a compressor can be utilized. Such compressor should be selected to provide pressures and motive gas flow sufficient to lift the motive gas/well fluid mixture from the wellbore through the inner tubing string. Additionally, the compressor preferably would be versatile enough to adapt to a wide range of inlet and discharge pressures. This versatility would allow the operator to adjust the discharge pressure or gas volume that feeds the pump, thereby allowing the operator to achieve optimum well bore protection and gas/fluid flow. Preferably, the pressure rating of the pump or compressor will be in excess of 1,000 PSIG.
A preferred embodiment of the present invention is illustrated in
It is also preferred that the components of the pump be constructed of materials suitable for prolonged use in a well environment, such as stainless steel. In a preferred embodiment, the pump is constructed out of 316 Stainless Steel to reduce the corrosive effects of exposure to carbonic acid and to reduce erosion from formation sand particles.
The invention has been described herein to enable one skilled in the art to practice and use the invention. It is understood that one skilled in the art will have the knowledge and experience to select suitable components and materials to implement the invention. Moreover, although the present invention has been described with respect to preferred embodiments, various changes, substitutions and modifications of this invention may be suggested to one skilled in the art, and it is intended that the present invention encompass such changes, substitutions and modifications. For example, although the diffuser assembly 100 (see
Claims
1. A downhole jet pump comprising:
- a plurality of elongated openings disposed circumferentially about a central jet nozzle, said plurality of openings communicable to an outside portion of at least one piece of an inner tubing string;
- a chamber providing a passageway from said plurality of elongated openings to an inlet of said central jet, said central jet comprising an outlet communicable to an inside of said inner tubing string.
2. The downhole jet pump of claim 1 further comprising a venturi disposed near said outlet of said central jet.
3. The downhole jet pump of claim 1 further comprising an outer tubing string, said outer tubing string disposed between an inner tubing string and a well casing.
4. The downhole jet pump of claim 2 wherein said venturi comprises an inlet in fluid communication with an outside of said inner tubing.
5. The downhole jet pump of claim 2 wherein said venturi comprises an inlet in fluid communication with an area between an outer tubing string and well casing.
6. The downhole jet pump of claim 1 wherein said plurality of elongated openings are communicable to a backside of a well.
7. The downhole jet pump of claim 1 further comprising a diffuser having an opening which is disposed between said central jet outlet and said inside of said inner tubing string.
8. The downhole jet pump of claim 7 wherein said diffuser opening comprises a substantially conical shape.
9. The downhole jet pump of claim 4 wherein pressurized gas flows from an outside of said inner tubing string, through said venturi, wherein said venturi causes an area of reduced pressure to be created which in turn draws liquids and/or gasses from an outside of said inner tubing string to an inside of said inner tubing string.
10. The downhole jet pump of claim 5 wherein said pressurized gas flows between an outside of said inner tubing string and an inside of said outer tubing string, through said venturi, wherein said venturi causes an area of reduced pressure to be created which in turn draws liquids and/or gasses from an outside of said outer tubing string to an inside of said inner tubing string.
11. The downhole jet pump of claim 1 wherein said jet pump is comprised of a plurality of subparts which connect to form said jet pump.
12. The downhole jet pump of claim 11 further comprising one or more pins and pin openings for enabling proper alignment of said subparts.
13. The downhole jet pump of claim 1 wherein pressurized gas is provided by a natural formation.
14. The downhole jet pump of claim 3 wherein pressurized gas is provided by injecting a pressurized gas between an area between an outer diameter of said inner tubing string and an inner diameter of said outer tubing string.
15. The downhole jet pump of claim 1 wherein said inner tubing string comprises a length of at least 100 feet.
16. The downhole jet pump of claim 1 wherein said inner tubing string comprises a length of at least 250 feet.
17. The downhole jet pump of claim 1 wherein said tubing string comprises a length of at least 500 feet.
18. A method for removing fluid from a well comprising the steps of:
- providing a string of casing tubing having at least one opening which is communicable to a hydrocarbon producing formation;
- providing an second string of tubing disposed within the casing tubing;
- positioning a jet pump on a terminal portion of the second string of tubing; and
- allowing a pressurized gas to travel between the casing tubing and the second string of tubing and through the jet pump wherein venturi action causes fluid to be sucked from outside the second string of tubing and ejected through an inner portion of the second string of tubing.
19. The method of claim 18 wherein the method is used to remove fluid buildup from a natural gas producing well.
20. The method of claim 18 wherein at least one of the openings comprises at least one perforation in the casing.
21. A method for removing fluid from a well comprising the steps of:
- providing a string of casing tubing having at least one opening which is communicable to a hydrocarbon producing formation;
- providing an outer tubing string disposed within an inside diameter of the casing tubing;
- providing an inner tubing string disposed within an inside diameter of the outer tubing string;
- positioning a jet pump on a terminal portion of an element selected from the inner tubing string, the outer tubing string and combinations thereof; and
- allowing a pressurized gas to travel between an outside diameter of the inner tubing string and an inner diameter of the outer tubing string, through the jet pump wherein venturi action causes fluid to be drawn from an area outside of the outer string of tubing and ejected through an inner portion of the inner string of tubing.
22. The method of claim 21 wherein the method is used to remove fluid buildup from a natural gas producing well.
23. A down hole jet pump comprising:
- a substantially conically-shaped diffuser opening;
- a venturi disposed such that an outflow of said venturi is communicably coupled to an inlet of said diffuser opening;
- an annulus for the transport of a pressurized gas to said venturi, said annulus comprising at least one central axis disposed substantially parallel with a central axis of said diffuser opening; and
- a liquids inlet disposed at or near a terminal portion of said jet pump which is opposite that of an outlet of said diffuser opening.
24. The downhole jet pump of claim 23 wherein said diffuser opening outlet is communicably coupled to at least one piece of tubing.
25. The downhole pump of claim 23 wherein said liquids inlet is communicably coupled to a backside of a well.
26. The downhole pump of claim 23 wherein said well comprises a hydrocarbon-producing well.
27. The downhole pump of claim 23 wherein said annulus is communicable to an area between an inner tubing string and an outer tubing string.
Type: Application
Filed: Jan 23, 2006
Publication Date: Oct 12, 2006
Applicants: MSE Technology Applications, Inc. (Butte, MT), New Mexico Tech Research Foundation (Socorro, NM)
Inventors: Kenneth Johnson (Framington, NM), William Lyons (Socorro, NM), Steven Johnson (Butte, MT), Stephan Kujawa (Butte, MT), Gloyd Simmons (Butte, MT), Bojana Nikolic-Tirkas (Butte, MT)
Application Number: 11/338,246
International Classification: E21B 43/00 (20060101);