Title:
Downhole jet pump
Kind Code:
A1


Abstract:
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.



Inventors:
Johnson, Kenneth G. (Framington, NM, US)
Lyons, William (Socorro, NM, US)
Johnson, Steven E. (Butte, MT, US)
Kujawa, Stephan T. (Butte, MT, US)
Simmons, Gloyd A. (Butte, MT, US)
Nikolic-tirkas, Bojana (Butte, MT, US)
Application Number:
11/338246
Publication Date:
10/12/2006
Filing Date:
01/23/2006
Assignee:
MSE Technology Applications, Inc. (Butte, MT, US)
New Mexico Tech Research Foundation (Socorro, NM, US)
Primary Class:
Other Classes:
166/105
International Classes:
E21B43/00
View Patent Images:
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Primary Examiner:
HARCOURT, BRAD
Attorney, Agent or Firm:
PEACOCK LAW P.C. (ALBUQUERQUE, NM, US)
Claims:
What is claimed is:

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.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

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 INVENTION

The 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 INVENTION

Increasing 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 INVENTION

The 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 DRAWINGS

For 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:

FIGS. 1A-1C depict, respectively, a side view, perspective view and exploded cross-sectional view of the downhole pump assembly of the present invention.

FIGS. 2A-2E depict, respectively, a left end view, side view, right end view, perspective view and cross-sectional view of the pump housing section of the downhole pump assembly of the present invention.

FIGS. 3A-3D depict, respectively, a left end view, side view, right end view, and cross-sectional view of the upper flow adapter section of the downhole pump assembly of the present invention.

FIGS. 4A-4E depict, respectively, a left end view, side view, right end view, perspective view and cross-sectional view of the lower flow adapter section of the downhole pump assembly of the present invention.

FIGS. 5A-5D depict, respectively, a side view, right end view, exploded perspective view and cross-sectional view of the diffuser section of the downhole pump assembly of the present invention.

FIGS. 6A-6E depict, respectively, a side view, right end view, perspective view, first cross-sectional view and second cross-sectional view of the mixing chamber section of the downhole pump assembly of the present invention.

FIGS. 7A-7C depict, respectively, an end view, cross-sectional view and perspective view of the downhole parallel section of the downhole pump assembly of the present invention.

FIGS. 8A-8C depict, respectively, a side view, cross-sectional view and perspective view of the jet nozzle section of the downhole pump assembly of the present invention.

FIGS. 9A-9B depict, respectively, a side view and cross-sectional view of the downhole pump assembly of the present invention indicating the flow paths for motive gases and well fluids through the pump.

FIGS. 10A-10D depict, respectively, a side view, an end view, a perspective view and a cross-sectional view of the downhole diffuser of the present invention.

FIG. 11 is a drawing which depicts a preferred embodiment of the present invention wherein the jet pump is disposed at or near terminal portions of inner and outer tubing strings which are themselves disposed within a well casing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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 FIGS. 1A-1C, there is shown a preferred embodiment of the pump assembly 10 of present invention. Pump assembly 10 includes as its main components a downhole diffuser assembly section 100, an upper flow adapter section 200, a pump housing section 300, a lower flow adapter section 400.

Referring to FIGS. 2A-2E, the pump housing section 300 shall be described. Pump housing section 300 includes an outer surface 310, a lower end 312 disposed further downhole when installed, and an upper end 314. (The use of the term “lower” herein generally refers to the portion of the pump structure positioned further downhole when the pump is installed. The term “upper” is used to refer to the opposite end of the subject pump structure positioned further up hole when the pump is installed.) Pump housing 300 is substantially cylindrical in shape and can be constructed out of any material suitable for use in a down hole wellbore environment, such as stainless steel. The outer diameter of the housing is about 3.5 inches in the preferred embodiment. Pump housing 300 includes a plurality of openings 320 (for motive gas flow) that extend longitudinally through the housing from upper end 314 to lower end 312. In addition to providing a conduit for the flow of motive gas, elongated openings 320 serve to reduce gas turbulence, thereby enhancing the efficiency of the pump. Another larger opening 330 also extends longitudinally through the housing. Opening 330 is disposed in the approximate center of the housing and has a slight taper from the upper end to the lower end. A flange 340 extends around the periphery of upper end 314, creating a recess 342. A dowel pin opening 316 is also formed in the upper end 314. Still referring to FIGS. 2A-2E, housing 300 further includes a lateral opening 370 which extends from opening 330 through the outer surface 310 of the housing. During pumping operations, opening 370 is plugged with plug 380 (FIG. 1C). Lower end 312 includes a flange 350 which extends around the periphery of lower end 312, creating a recess 352. Also disposed at the lower end of the housing is tube opening 360 which extends from lateral opening 370 into recess 352. In a preferred embodiment, as shown in FIG. 2E, openings 330, 316, and 360 have chamfered edges to allow for easier mating with other pump assembly components to be described hereafter. In a most preferred embodiment of the invention, the pump housing 300 has the dimensions and specifications indicated in FIGS. 2A-2E.

Referring to FIGS. 3A-3D, there is shown the upper flow adapter section 200 of the pump assembly. Upper flow adapter section 200 has an upper end 212 and lower end 214. Opening 220 extends longitudinally through the center of the flow adapter. The diameter of opening 220 is greater at upper end 212 and tapers down to a lesser diameter at the lower end 214 to substantially correspond to the diameter of the opening 330 in pump housing 300. A plurality of openings 230 (for motive gas flow), which surround opening 220 at lower end 214, extending longitudinally through the flow adapter. In addition to providing a conduit for the flow of motive gas, elongated openings 230 serve to reduce gas turbulence, thereby enhancing the efficiency of the pump. When the components of the pump are assembled, openings 230 will align with the motive gas openings 320 in the pump housing section 300. A dowel pin opening 240 is included at the lower end 214 and corresponds with the dowel pin opening in the pump housing, allowing for the proper alignment of the upper flow adapter section 200 with the pump housing 300. Lower end 214 has a reduced outer diameter allowing lower end 214 to be seated in recess 342 (FIG. 2E) at the upper end of the pump housing. Upper end 212 has a reduced outer diameter to allow the upper flow adapter to be connected to an outer tubing string that extends to the surface. Preferably upper end 212 includes threads and is threaded to the outer tubing string. The preferred dimensions and specifications for upper flow adapter 200 are shown in FIGS. 3A-3D.

Referring to FIGS. 4A-4E, there is shown the lower flow adapter section 400 of the pump assembly. Lower flow adapter section 400 has an upper end 412 and lower end 414. A tube opening 410 extends longitudinally through the lower flow adapter. Upper end 412 includes a recess 420. Upper end 412 also has a reduced outer diameter, allowing upper 412 to be seated within recess 352 at the lower end of the pump housing 300. Lower end 414 has a reduced outer diameter to allow for the attachment (preferably threaded attachment) of an additional tubing section(s) below the lower flow adapter. When the pump is assembled, a tube 450 will extend through opening 410 in the lower flow adapter and will be seated within opening 360 in the pump housing (see FIGS. 1C and 9B). The preferred dimensions and specifications for lower flow adapter 400 are shown in FIGS. 4A-4E.

Referring to FIGS. 5A-5D, there is shown the diffuser assembly 100 of the pump. Diffuser assembly 100 includes a diffuser section 102, a parallel section 120, a mixing chamber section 140, and a jet nozzle 160. As shown in FIGS. 5D and 10A-10D, diffuser section 102 has an upper end 104 and a lower end 106. In the preferred embodiment, the upper end of the diffuser section is attached to a tubing string (not shown) that extends to the surface of the well. As shown in FIGS. 5D and 10D, an opening 110 at the center of the diffuser section extends longitudinally through the section. As shown, opening 110 tapers outwardly (i.e., expands in diameter) from the lower end 106 to the upper end 104. Dowel pin openings 112 are provided at the lower end of the diffuser. As shown (FIGS. 5A, 5C-5D and 7A-7C), parallel section 120 is seated on the lower end 106 of the diffuser section and has a centered opening 130 which extends longitudinally through the section. Dowel pin openings 140 extend longitudinally through the parallel section and are aligned with the dowel pin openings 112 on the diffuser when the pump is assembled. The preferred dimensions and specifications for the diffuser section are shown in detail in FIGS. 10A-10D. The preferred dimensions and specifications for the parallel section are shown in detail in FIGS. 7A-7C.

Referring to FIGS. 5A-5D and 6A-6E the mixing chamber section 140 of the diffuser assembly 100 shall be described. Mixing chamber 140 has a lower end 142 and upper end 144. Mixing chamber 140 is generally cylindrical and tapers to a slightly smaller diameter from its upper end 144 to lower end 142. The degree of taper corresponds with the tapered opening 330 in pump housing 300 (FIG. 2E) so as to provide a metal to metal taper fit when the mixing chamber section is disposed within the pump housing. As shown in FIGS. 6D and 6E, the mixing chamber section has a centered opening 150 that extends longitudinally through the section. Opening 150 has (a) a first portion 152 adjacent lower end 142 having a substantially constant diameter and (b) a second portion 154 having a diameter which tapers downward toward the upper end 144. At the upper end 144 there are a pair of dowel openings 146 which align with the dowel openings 140 in the parallel section 120 (see e.g., FIGS. 1C and 5C). At the lower end 142 there are a plurality of lateral inlet openings 180 about the periphery of the mixing chamber section. Openings 180 extend through the mixing chamber walls into the first portion 152 of opening 150. At the lower end of the mixing chamber there is also a ledge or flange 190 on which the nozzle will seat when the pump is assembled. A notch 192 is provided about the periphery of opening 150 at the lower end 142. Seated within notch 192 is a ring 194 (e.g., a stainless steel snap ring) (FIG. 5C). When the pump is assembled, dowel pins 180 (FIG. 5C) extend into the dowel pin openings 146 (mixing chamber section), through dowel pin openings 140 (parallel section), and into dowel pin openings 112 (diffuser section). The preferred dimensions and specifications for the mixing chamber section are shown in detail in FIGS. 6A-6E and the detailed drawings corresponding to FIGS. 6A-6E.

Referring to FIGS. 5C-5D and FIGS. 8A-8C the jet nozzle 160 of the diffuser assembly 100 shall be described. Jet nozzle 160 includes a lower end 162 and upper end 164. As shown, the nozzle has a centered opening 166 that extends longitudinally through it. Opening 166 has (a) a first portion 168 adjacent lower end 162 having a substantially constant diameter and (b) a second portion 170 having a diameter which tapers downward toward the upper end 164. A flange or ledge 172 extends about the outer periphery of the nozzle at the lower end 162. Flange 172 is designed to rest upon the ledge 190 in the mixing chamber section, thus seating the nozzle within the mixing chamber. The exterior surface of the nozzle includes (a) a first portion (adjacent the lower end 162) which is substantially untapered and (b) a second portion (adjacent upper end 164) which tapers downwardly toward the upper end 164. As depicted in the drawings, the shape of the exterior surface of the nozzle is designed to substantially correspond with the shape of the opening 150 in the mixing chamber section 140. The preferred dimensions and specifications for the mixing jet nozzle are shown in detail in FIGS. 8A-8C.

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 FIGS. 9A-9B. In its typical use, the pump is disposed downhole in a well adjacent the bottom of the well or the hydrocarbon-producing formation. In the preferred embodiment depicted, the upper flow adapter 200 is attached to an outer tubing string 880 that extends to the surface and the diffuser 102 is attached to an inner tubing string 890 that also extends to the surface. As shown, motive gas (i.e., the gas that operates the pump) is injected into the annulus between the inner and outer tubing strings and then enters the annulus 800 between outer surface of the diffuser 102 and the inner surface of the untapered portion of opening 220 in the upper flow adapter 200. The motive gas then flows through openings 230 in the upper flow adapter 200 and into openings 320 of the pump housing 300. From openings 320, motive gas then flows into the chamber 810 created between the recess 352 (in the pump housing) and the upper end 412 of the lower flow adapter 400. Next, the pressurized motive gas enters the opening 166 in the jet nozzle 160 and passes into the opening 130 in parallel section 120. The flow of the motive gas into the parallel section 120 creates a region of reduced pressure within and adjacent opening 130, causing water and other well fluids to flow from the wellbore through tube 450, then through opening 370, then through openings 180, then through the annulus 850 between the exterior surface of the nozzle 160 and the inner surface of the opening 330 in pump housing 300, and then into the opening 130 in parallel section 120 where such well fluids mix with the motive gas. Finally, as indicated in FIG. 9B, the motive gas and water (well fluids) mixture enters the diffuser opening 110 where the pressure is such that the mixture flows to the surface through the inner tubing string 890 attached to the upper end of the diffuser.

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 FIG. 11. As illustrated therein, jet pump 900, as mechanically and functionally illustrated in the preceding paragraphs is preferably disposed at or near terminal portions of outer tubing string 910 and inner tubing string 920. Inner tubing sting 920 is preferably disposed within outer tubing string 910 which itself is preferably disposed within well casing 930. Motive gas is preferably injected in annular space 925 at or near an upper end of the tubing strings. Motive gas then travels through annular space 925, through jet pump 900, thus causing fluid 940 to be drawn into inlet 960, through jet pump 900, and ejected as atomized fluid through an inner portion of inner tubing string 920 such that it may be collected and/or separated at or near an upper portion of the tubing strings. Those skilled in the art will readily recognize that fluid 940 is produced at, near, or otherwise travels through production zone 950 before it accumulates at a bottom of well casing 930. When fluid 940 builds to such an extent that it travels up the well casing to a distance above perforation 975, at some point, depending upon the gas pressure generated by the specific production zone for each specific well, the hydrostatic pressure of fluid 940 equals the ambient pressure of gas which originates from formation 950; when this occurs, production of gas from formation 950 ceases. Injecting motive gas through annulus 925, and thus removing fluid 940, enables gas production to continue

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 FIG. 5C) is depicted and described herein as being constructed of multiple components (i.e., a diffuser section 102, a parallel section 120, and a mixing chamber section 140), it is understood and intended that the assembly could be constructed as a single part (e.g., by casting the structure). The entire disclosures of all references, applications, patents, and publications cited above are hereby incorporated by reference.