Patent Publication Number: US-10309425-B1

Title: High flow capacity well fluid extraction jet pump providing through access

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. provisional application No. 62/207,436, filed Aug. 20, 2015 and entitled HIGH FLOW CAPACITY WELL FLUID EXTRACTION JET PUMP PROVIDING THROUGH ACCESS, which provisional application is incorporated by reference herein in its entirety, and this application is related to U.S. application Ser. No. 13/771,347, filed Feb. 20, 2013 and entitled WELL FLUID EXTRACTION JET PUMP PROVIDING ACCESS THROUGH AND BELOW PACKER. 
    
    
     FIELD 
     Illustrative embodiments of the disclosure generally relate to jet pumps. More particularly, illustrative embodiments of the disclosure relate to application of jet pumps used for artificial lift hydrocarbon well production applications. Illustrative embodiments of the disclosure further relate to methods of extracting well fluids from a subterranean well by operation of a high efficiency, high flow capacity, reversible operation, hydraulically-retrievable jet pump which allows maintenance access through the pump to well depths below the pump. 
     BACKGROUND 
     All methods of lifting gas, oil, or water from subterranean wells, referred to as “artificial lift”, are utilized when the well is deficient of sufficient internal pressure to push the fluid to the ground surface. Of the long-established various methods of lift, the jet pump, or venturi, or eductor, has been sparingly utilized since the early twentieth century. They all work on the concept of conservation of energy, and subsequently, Bernoulli&#39;s Principle, stating that the total pressure head in an ideal non-compressible flowing fluid remains the same at any given point in the flow stream. So, by constricting the flow, as in a converging nozzle, the stream must flow faster. And, when flowing faster, Bernoulli&#39;s Principle illustrates that the associated stream pressure must decrease. This decrease is often utilized, as in a jet pump to draw in other objective fluids to be transported with the original stream. 
     A conventional jet pump generally includes a jet pump housing, a nozzle having a converging nozzle bore in the jet pump housing, a nozzle tip which communicates with the nozzle bore and terminates in a nozzle chamber, a mixing chamber which communicates with the nozzle chamber and a diverging passage called diffuser which communicates with the mixing chamber. As it flows through the nozzle, a pressurized power fluid creates a smaller, higher velocity stream which draws a suction fluid (the objective fluid) into the nozzle chamber and further into the mixing chamber. The mixed fluid velocity reduces in the diverging, diffuser passage following the mixing chamber, increasing the pressure of the fluid. The fluid mixture is transported to a selected station. Jet pumps are suitable for a variety of applications including downhole well applications in which the pumps may be used to retrieve well reservoir fluid containing hydrocarbons to the well surface. 
     In typical downhole hydrocarbon production applications, the jet pump housing of a jet pump is directly or indirectly attached to a tubing string which is inserted in a well bore, above but in a line connected with the packer, a common device long utilized by those skilled in the art. Power fluid is pumped from the ground surface through the tubing string into the jet pump. As the power fluid flows through the nozzle in the jet pump housing, reservoir fluid from the well bore is drawn from below the packer, through the standing valve  102  (or safety valve, known by those skilled in the art) into the jet pump via a pressure drop generated by the power fluid exiting the nozzle. This reservoir fluid mixes with the power fluid. The fluid mixture, which includes power fluid and reservoir fluid, flows through the jet pump to the well annulus area between the pump housing and well casing to the well surface or up the tubing string in case of reverse flow. 
     One of the limitations of conventional jet pumps which are used in hydrocarbon well production applications is that the diffuser and/or other components of the jet pump may be immovably attached to the jet pump housing. Consequently, these components hinder downhole cleaning and/or maintenance operations in the well bore below the pump and thus, the tubing string must be removed from the well bore for jet pump housing removal in order to perform these operations. One exception to this is the use of a smaller size conventional jet pump mounted inside a sleeve. This sleeve matches the O.D. and I.D. of the tubing string. This smaller jet pump is removable/retrievable in its entirety by wireline, thereby leaving maintenance to the well below the pump. 
     In subterranean wells, the jet pump flow stream, or power fluid, is pumped from the ground surface and may include water, oil or gas. The generated Venturi pressure drop is used to draw in reservoir fluid, and the surface pump pressure pushes the combined power fluid and reservoir fluid to the surface where the two are separated, and the operation of artificial lift is continuous. 
     Standards within the well drilling and production industries have evolved over time, and these standards apply to safety and convenience. The standards include specifications for well casing and tubing and the relationships these have to each other in size. So, for any given well, there are established ranges of dimensions for the production tubing or tubing string and the casing. These fixed dimensions set the limits for tooling sizes such as those for jet pumps. By design, jet pumps operate at very high fluid flow velocities. These flow velocities, in combination with differing well conditions. frequently produce undesirable and often unpredictable undesirable effects on the mechanical components of jet pumps. Downhole reservoir condition variables can include varying fluids constituencies, fluid constituency percentages variation, entrapped gasses, high temperatures, high and varying pressures, corrosives, and solid contaminants, some of which can be very abrasive. 
     In consideration of all of these well variables, along with the need to minimize the cost of operating the jet pump and lifting the combined fluids to the surface, the jet pump design becomes a very important factor in the operation. Jet pumps often require 3000 to 4500 psi power fluid surface pump pressure to operate, combined with another 3000 to 4500 psi to lift the fluid to the surface. Production capacities for jet pump wells can vary widely but frequently reach 4000 barrels per day. and can reach more. The result is a surface pump system which is large and quite costly. In addition to this. the cost of electrical power to operate the surface pump system can be substantial, particularly in times of economically depressed commodity prices. 
     Therefore, it becomes imperative for the jet pump to operate as efficiently as possible, reliably, and uninterrupted for as long as possible. Maintaining operational efficiency of a well requires constant attention to the well variables. As the variables change, there can be differing production equipment demands. Performance of jet pumps is directly related to the component sizes and resulting output stream magnitude. Also, conditions of the well often impart abrasive wear or erosion on jet pump components. These conditions necessitate maintenance, and accordingly, retrieval of the jet pump to the surface. All of this work must be performed as efficiently as possible. 
     Because subterranean formations are dynamic, wells require maintenance. As discussed above, there can be a variety of effects to the casing and production tubing from natural reservoir activity. Results may include plugging of the well, perforations, safety valve or standing valve (check valve), or simply buildup of paraffin or scale on the tubing surfaces, along with a host of other maintenance-requiring occurrences. These conditions require clear access through the tubing and jet pump to the lower well depths. 
     Some wells exhibit casing which may be old and deteriorated or may be vulnerable to abrasive/corrosive contaminant entrained reservoir fluid flow. Conventional jet pump-configured wells operate by surface power fluid pumped down the production tubing, and this along with production fluids lifted in the annulus between the tubing and the casing. Where this is not allowed due to casing erosion concerns, the reverse procedure must be utilized. Therefore, optimum design of a jet pump should include features in addition to good metallurgical practices for long erosion, corrosion, and abrasive wear life as follows: 
     1. Simple design with no moving, and minimal number of components; 
     2. Through-flow hydraulically optimized, with fewest fluid turns, most gradual turns, most gradual divergences, minimal laminar flow interruptions and largest flow port cross-sectional areas possible; 
     3. Capability of efficient reversing of the jet pump assembly (nozzle and mixing tube) for lifting production fluid up either the annulus or the tubing; 
     4. Capability of reliable, efficient, ordinary, and possible frequent removal of the jet pump assembly, while in the well, leaving the unobstructed bore of the jet pump housing, which dimensionally closely matches the internal diameter of the connecting production tubing; 
     5. Performance which minimizes surface pump power requirements; and 
     6. Results in maximum possible production. 
     Accordingly, this invention describes a high flow capacity reversible operation jet pump which includes a housing that is attached to a tubing string and from which a jet pump assembly including the functional components of the jet pump can be selectively removed from the housing while the housing remains in place in the tubing string, allowing for unobstructed cleaning and/or maintenance of the well bore. A high flow capacity reversible operation jet pump which includes a jet pump assembly that can be selectively re-oriented in the jet pump housing to facilitate reversible operation, in combination with the fore-stated through accessibility, of the jet pump is included. The jet pump is streamline improved for more efficient flow. Flow through the jet pump exhibits reduced velocities via larger flow ports, as suction ports are located inside the housing walls away from the jet pump assembly. 
     SUMMARY 
     An illustrative embodiment of a through-accessible and high flow capacity reversible operation jet pump for attachment to a tubing string includes a pump housing including a pump housing wall and a pump housing interior in the pump housing wall. At least one suction port is in the pump housing wall. The at least one suction port has a suction port inlet and a suction port outlet disposed in fluid communication with the pump housing interior. A jet pump assembly is disposed in the pump housing interior. The jet pump assembly includes a proximal carrier head disposed in sealing engagement with the pump housing wall, a carrier disposed in fluid communication with the proximal carrier head, a carrier nozzle in the carrier, at least one carrier opening in the carrier and establishing fluid communication between the carrier nozzle and the suction port outlet of the at least one suction port through the pump housing interior, a distal carrier head disposed in sealing engagement with the pump housing wall and having a distal carrier head bore disposed in fluid communication with the carrier and a pump spool having a tapered spool shaft terminating inside the distal carrier head bore of the distal carrier head. The pump spool is disposed in sealing engagement with the pump housing wall between the suction port inlet and the suction port outlet of the at least one suction port. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Illustrative embodiments of the disclosure will now be described, by way of example, with reference to the accompanying drawings, in which: 
         FIG. 1  is a longitudinal sectional view of an illustrative embodiment of the through-accessible high flow capacity reversible operation jet pump, more particularly illustrating a first configuration of the pump in which a jet pump assembly is oriented in a first orientation in a pump housing and power fluid (not illustrated) flows in a first direction through the pump; 
         FIG. 2  is a longitudinal sectional view of a pump spool component of the jet pump assembly of the through-accessible high flow capacity reversible operation jet pump; 
         FIG. 3  is a cross-sectional view of a spool collar of the pump spool, taken along section lines  3 - 3  in  FIG. 2 ; 
         FIG. 4  is a cross-sectional view of the pump housing and pump spool of the through-accessible high flow capacity reversible operation jet pump, taken along section lines  4 - 4  in  FIG. 1 ; 
         FIG. 5  is a longitudinal sectional view, taken along section lines  5 - 5  in  FIG. 3 , of a typical collar vane in the spool collar; 
         FIG. 6  is a longitudinal sectional view of a typical jet pump assembly of the through-accessible high flow capacity reversible operation jet pump, removed from the pump housing; 
         FIG. 7A  is a longitudinal sectional view of the through-accessible high flow capacity reversible operation jet pump, deployed in a well casing in a subterranean well with the jet pump assembly oriented in the first orientation, more particularly illustrating flow of power fluid downwardly through the jet pump and then into and upwardly through the annulus between the well casing and the jet pump housing to the well surface, respectively, to draw reservoir fluid from the well to the well surface with the power fluid in a typical first fluid flow direction operational mode of the pump; 
         FIG. 7B  is an enlarged longitudinal sectional view of a typical carrier nozzle-mixing tube assembly inside the jet pump assembly, oriented in the first orientation of  FIG. 7A , more particularly illustrating flow of power fluid and reservoir fluid in the carrier nozzle-mixing tube assembly in the first fluid flow direction operational mode of the through-accessible high flow capacity reversible operation jet pump; 
         FIG. 8A  is a longitudinal sectional view of the through-accessible high flow capacity reversible operation jet pump, deployed in a well casing in a subterranean well with the jet pump assembly oriented in the second orientation, more particularly illustrating flow of power fluid downwardly through the annulus between the pump housing and the well casing and then into and upwardly through the jet pump to the well surface, respectively, to draw reservoir fluid from the well to the well surface with the power fluid in a typical second fluid flow direction operational mode of the pump; 
         FIG. 8B  is an enlarged longitudinal sectional view of the carrier-nozzle mixing tube assembly inside the jet pump assembly, oriented in the second orientation of  FIG. 8A , more particularly illustrating flow of power fluid and reservoir fluid in the carrier-nozzle mixing tube assembly in the second fluid flow direction operational mode of the through-accessible high flow capacity reversible operation jet pump; 
         FIG. 9  is a longitudinal sectional view of the pump housing, inside the well casing with the jet pump assembly of the jet pump removed from the pump housing for cleaning or maintenance of depths within the well bore below the pump housing; 
         FIG. 10  is a longitudinal sectional view of the well casing, with the reversible operation jet pump disposed in the well casing oriented in the first orientation of  FIG. 7A  and coupled to a standing valve (shown in  FIG. 11 ), more particularly illustrating typical flow of power fluid in initiating hydraulic retrieval of the reversible operation jet pump from the well casing; and 
         FIG. 11  is a longitudinal sectional view of the well casing and reversible operation jet pump, more particularly illustrating typical flow of power fluid in hydraulic retrieval of the reversible operation jet pump from the well casing. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description is merely exemplary in nature and is not intended to limit the described embodiments or the application and uses of the described embodiments. As used herein, the word “exemplary” or “illustrative” means “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” or “illustrative” is non-limiting and is not necessarily to be construed as preferred or advantageous over other implementations. All of the implementations described below are exemplary implementations provided to enable persons skilled in the art to practice the disclosure and are not intended to limit the scope of the appended claims. Moreover, the illustrative embodiments described herein are not exhaustive and embodiments or implementations other than those which are described herein and which fall within the scope of the appended claims are possible. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. Relative terms such as “upper”, “lower”, “above”, ‘below”, “top”, “horizontal” and “vertical” as used herein are intended for descriptive purposes only and are not necessarily intended to be construed in a limiting sense. As used herein, the term “proximal” means “closer to the well surface” whereas the term “distal” as used herein means “further from the well surface”. 
     Referring initially to  FIGS. 1-6 and 7B  of the drawings, an illustrative embodiment of the well fluid extraction through-accessible high flow capacity reversible operation jet pump providing unobstructed access through and below packer and/or the jet pump, hereinafter jet pump, is generally indicated by reference numeral  1  in  FIG. 1 . The jet pump  1  includes a pump housing  2 . The pump housing  2  includes a pump housing wall  3  which may be generally elongated and cylindrical. The pump housing wall  3  of the pump housing  2  has a pump housing interior  4 . The pump housing  2  may have a proximal housing end  5  and a distal housing end  6  at opposite ends of the pump housing interior  4 . At least one pump housing opening  7  may extend through the pump housing wall  3  of the pump housing  2  in fluid communication with the pump housing interior  4  for purposes which will be hereinafter described. As further illustrated in  FIG. 1 , in some embodiments. the pump housing  2  may include an upper or proximal housing portion  2   a  and a lower or distal housing portion  2   b  which is sealingly coupled to the proximal housing portion  2   a  via threading or otherwise according to the knowledge of those skilled in the art. In other embodiments, the pump housing  2  may be fabricated in one piece. A jet pump assembly  10  is disposed in the pump housing interior  4  of the pump housing  2  for purposes which will be hereinafter described. 
     As illustrated in  FIG. 1 , multiple suction ports  8  may extend through and along a distal portion of the pump housing wall  3  of the pump housing  2 . The suction ports  8  may be oriented in generally parallel relationship to the longitudinal axis of the pump housing  2 . As illustrated in  FIG. 4 . in cross-sectional view, the suction ports  8  may be arranged in spaced-apart relationship to each other around the circumference of the pump housing  2 . Accordingly, the suction ports  8  may form longitudinally-extending undulations  96  which are spaced about the circumference in the exterior surface or O.D. (Outer Diameter) of the pump housing wall  3  of the pump housing  2  to maximize the cross-sectional area for flow of fluid within the pump housing interior  4 . The undulations  96  may correspond in number and position to the respective suction ports  8  in the pump housing  2 . Each suction port  8  may have a suction port inlet  8   a  and a suction port outlet  8   b . The suction port inlet  8   a  may be disposed in fluid communication with the portion of the pump housing interior  4  which is below or distal to the jet pump assembly  10 . The suction port outlet  8   b  may be disposed in fluid communication with an annular reservoir fluid flow space  75  in the pump housing interior  4 . The fluid flow space  75  may be formed by and between the interior surface of the pump housing wall  3  and the exterior surface of the jet pump assembly  10 . 
     The jet pump assembly  10  is selectively removable from the pump housing interior  4  for purposes which will be hereinafter described. As particularly illustrated in  FIG. 6 , the jet pump assembly  10  may include an upper or proximal carrier head  11  which is normally generally proximate the upper or proximal housing end  5  of the pump housing  2  ( FIG. 1 ). The upper or proximal carrier head  11  has a proximal carrier head bore  12 . 
     As further illustrated in  FIG. 6 , in some embodiments, the proximal carrier head  11  of the jet pump assembly  10  may include a proximal carrier head base  90 . The proximal carrier head base  90  may have exterior base threads  91  which facilitates coupling of the pump housing  2  to a setting tool  88  (not shown but understood by those skilled in the art) in installation of the jet pump  1  in the well casing  70 , which will be hereinafter described. An annular flared housing contact portion  92  (referred to as “go-no-go contact seal” in the industry) may protrude outwardly from the proximal carrier head base  90 . A proximal carrier head body  93  may extend from the flared portion  92 . The proximal carrier head body  93  may have exterior body threads  98  for purposes which will be hereinafter described. A proximal carrier head neck  18  may extend from the proximal carrier head body  93  for attachment purposes as will be hereinafter described. The proximal carrier head neck  18  may have exterior neck threads  19  for purposes which will be hereinafter described. 
     As illustrated in  FIG. 1 , at least one proximal seal  15  may be sandwiched between a proximal carrier head outer surface  13  of the proximal carrier head  11  and an interior surface of the pump housing interior  4  to impart a fluid-tight seal between the proximal carrier head  11  and the pump housing wall  3 . An interiorly-threaded proximal seal retaining collar  38  may be threaded on the exterior body threads  98  on the proximal carrier head body  93  of the proximal carrier head  11  to retain the proximal seals  15  in place. 
     The jet pump assembly  10  may further include a lower or distal carrier head  44 . As illustrated in  FIG. 6 , the lower or distal carrier head  44  may have an upper or proximal head end  45  and a lower or distal head end  46  and a distal carrier head bore  51  which diverges from the proximal head end  45  to the distal head end  46 . In some embodiments, the distal carrier head  44  may include a distal carrier head base  47 . The distal carrier head base  47  may have interior base threads  48  for purposes which will be hereinafter described. A distal carrier head body  49  may extend from the distal carrier head base  47 . Exterior body threads  50  may be provided on the distal carrier head body  49  for purposes which will be hereinafter described. A distal carrier head tapered portion  52  may extend from the distal carrier head body  49 . Exterior distal carrier head threads  53  may be provided on the distal carrier head tapered portion  52  for purposes which will be hereinafter described. 
     As illustrated in  FIG. 1 , at least one middle seal  55  may be sandwiched between the exterior surface of the distal carrier head body  49  and the interior surface of the pump housing interior  4  to impart a fluid-tight seal between the distal carrier head  44  and the interior surface of the pump housing wall  3 . An interiorly-threaded middle distal seal retaining collar  40  may be threaded on the exterior body threads  50  ( FIG. 6 ) on the distal carrier head body  49  of the distal carrier head  44  to retain the middle seals  55  in place. 
     As illustrated in  FIG. 6 , the jet pump assembly  10  may include a pump spool  60  which is coupled to the distal carriage head  44 . As particularly illustrated in  FIG. 2 , the pump spool  60  may include a spool base  61 . The spool base  61  may have an interiorly-threaded spool bushing opening  66  which threadably receives a spool bushing  67  ( FIG. 6 ). An annular flared housing contact portion  62  may protrude from the spool base  6 I. A tapered spool body  63  may extend from the flared spool portion  62 . An elongated, tapered spool shaft  64  having a spool tip  65  may extend from the spool body  63 . 
     A spool collar  80  accommodates the spool shaft  64  of the pump spool  60 . The spool collar  80  may include an annular spool collar base  81 . A cylindrical spool collar wall  82  may extend from the spool collar base  81 . The spool collar wall  82  may have exterior spool collar threads  83 . Fluid flow spaces  84  may extend through the spool collar base  81  and the spool collar wall  82 . Multiple collar vanes  85  may separate adjacent fluid flow spaces  84  from each other. The collar vanes  85  may attach the spool collar wall  82  to the spool shaft  64  of the pump spool  60 . 
     As illustrated in  FIG. 6 , the spool collar  80  on the pump spool  60  may be coupled to the distal carrier head base  47  of the distal carrier head  44  by threaded engagement of the exterior spool collar threads  83  on the spool collar  80  with the companion interior base threads  48  in the distal carrier head base  47  of the distal carrier head  44 . Accordingly, the spool tip  65  of the pump spool  60  terminates inside the distal carrier head bore  51  of the distal carrier head  44 . As illustrated in  FIG. 1 , at least one distal seal  78  may be sandwiched between the spool base  61  of the pump spool  60  and the pump housing wall  3  of the pump housing  2 . A distal seal retaining collar  79  may threadably engage the spool base  61  to retain the distal seals  78  in place. 
     As further illustrated in  FIG. 6 , the jet pump assembly  10  may include a carrier  22  which is detachably coupled to and extends between the proximal carrier head  11  and the distal carrier head  44 . The carrier  22  can be selectively attached to the proximal carrier head  11  and the distal carrier head  44  in a first orientation ( FIGS. 1, and 7A and 7B ) to facilitate flow of fluid through the jet pump assembly  10  in a downward direction. The carrier  22  can be selectively detached from and then re-attached to the proximal carrier head  11  and the distal carrier head  44  in a second orientation ( FIGS. 8A and 8B ) to facilitate flow of fluid through the jet pump assembly  10  in an upward direction for purposes which will be hereinafter described. The carrier  22  may have a carrier inlet end  23  and a carrier outlet end  24 . The carrier inlet end  23  may have interior inlet threads  23   a  and the carrier outlet end  24  may have interior outlet threads  24   a  for attachment purposes as will be hereinafter described. 
     A carrier nozzle  26  is disposed inside the carrier  22  and includes a nozzle bore  27  which converges towards the carrier outlet end  24 . As illustrated in  FIG. 7B , a nozzle tip  28  terminates the nozzle bore  27 . A nozzle chamber  29  in the carrier  22  communicates with the nozzle tip  28 . At least one carrier opening  30  in the carrier  22  establishes communication between the nozzle chamber  29  and the reservoir fluid flow space  75  in the pump housing interior  4  of the pump housing  2 . As illustrated in  FIG. 6 , in some embodiments, a nozzle spacer  36 , having a tapered nozzle spacer bore (not numbered) which converges toward the carrier outlet end  24  of the carrier  22 , may be disposed between the tapered converging proximal carrier head bore  12  of the proximal carrier head  11  and the converging nozzle bore  27  of the carrier nozzle  26 . The nozzle spacer  36  imparts smooth continuity between the interior surface of the proximal carrier head bore  12  and the interior surface of the converging nozzle bore  27  of the carrier nozzle  26 . 
     A mixing chamber  32  communicates with the nozzle chamber  29 . The mixing chamber  32  may include a straight chamber segment  33  which extends from the nozzle chamber  29  and a diverging chamber segment  34  which extends from the straight chamber segment  33 . The diverging chamber segment  34  may terminate generally at or adjacent to the interior outlet threads  24   a  of the carrier  22 . In some embodiments, a mixing chamber spacer  42 , having a tapered mixing chamber spacer bore (not numbered) which diverges toward the carrier outlet end  24 , may be disposed between the tapered diverging chamber segment  34  of the mixing chamber  32  and the diverging distal carrier head bore  51  of the distal carrier head  44 . The mixing chamber spacer  42  imparts smooth continuity between the interior surface of the diverging chamber segment  34  and the interior surface of the diverging distal carrier head bore  51  of the distal carrier head  44 . 
     Referring next to  FIGS. 7A, 7B, 8A and 8B  of the drawings, in exemplary application, the jet pump  1  is attached to a tubing string  58  and inserted in a well casing  70  deployed in a subterranean hydrocarbon well to extract, or artificial lift reservoir fluid  74  from the well. The reservoir fluid  74  which is extracted from the well may include water as well as hydrocarbons. At the well surface, the hydrocarbons may be separated from the extracted reservoir fluid  74  using techniques which are well known by those skilled in the art. In some applications, the well casing  70  may be disposed in a vertical orientation, as illustrated in  FIGS. 7A and 8A . Thus, the following description is based on a vertical orientation of the well casing  70  in the subterranean hydrocarbon well. It is to be understood, however, that in other applications, the well casing  70  may be disposed in a horizontal orientation or in any orientation between a vertical orientation and a horizontal orientation. 
     At the well surface, the pump housing  2  of the reversible operation jet pump  1  may be attached to the tubing string  58  typically via a threaded coupling (not illustrated). The pump housing  2  and tubing string  58  are lowered into the well casing  70 . At the desired depth, the packer  68  may have been deployed in the well casing  70  typically by extending gripping elements (not illustrated) from the packer  68  which engage the well casing  70  typically via rotation of the tubing string  58  in the conventional manner. A setting tool  88  may be threadably coupled to the exterior base threads  91  on the proximal carrier head base  90  of the jet pump assembly  10  to facilitate placement of the jet pump assembly  10  in the pump housing  2  when not set in place initially and, in some cases, extraction of the jet pump assembly  10  from the pump housing  2 . 
     As illustrated in  FIGS. 7A and 7B , in a first fluid flow direction operational mode of the jet pump  1 , the carrier  22  of the jet pump assembly  10  may be configured in a first orientation in the pump housing interior  4  to facilitate downward flow of power fluid  72  (which may include water and/or oil, for example and without limitation) from the well surface through the tubing string  58  and the jet pump assembly  10 , respectively, and upward flow of a fluid mixture  76  of power fluid  72  and reservoir fluid  74  to the well surface through the well annulus  71  between the pump housing  2  and the well casing  70 . As illustrated in  FIG. 8A , in a second fluid flow direction operational mode of the reversible operation jet pump  1 , the carrier  22  of the jet pump assembly  10  may be configured in a second orientation in the pump housing interior  4  to facilitate downward flow of power fluid  72  from the well surface through the well annulus  71  and upward flow of a fluid mixture  76  of power fluid  72  and reservoir fluid  74  to the well surface through the jet pump assembly  10  and the tubing string  58 , respectively. The jet pump assembly  10  is selectively configured in the first orientation ( FIG. 7A ) by orienting the carrier  22  such that the carrier nozzle  26  accommodates downward flow of power fluid  72  through the jet pump assembly  10 . This is accomplished by coupling the carrier inlet end  23  of the carrier  22  to the proximal carrier head neck  18  of the proximal carrier head  11  and coupling the carrier outlet end  24  of the carrier  22  to the distal carrier head tapered portion  52  of the distal carrier head  44 . The jet pump assembly  10  is selectively configured in the second orientation ( FIG. 8A ) by orienting the carrier  22  such that the carrier nozzle  26  accommodates upward flow of power fluid  72  and reservoir fluid  74  through the jet pump assembly  10 . This is accomplished by coupling the carrier inlet end  23  of the carrier  22  to the distal carrier head tapered portion  52  of the distal carrier head  44  and coupling the carrier outlet end  24  of the carrier  22  to the proximal carrier head neck  18  of the proximal carrier head  11 . 
     In either fluid flow direction operational mode of operation, as the reversible operation jet pump  1  is inserted in place in the well casing  70  on the tubing string  58 , the reservoir fluid  74  in the well flows upwardly through the lower portion of the pump housing interior  4 , the suction ports  8  and the reservoir fluid flow space  75  in the pump housing  2 . The reservoir fluid flow space  75  generally surrounds the carrier  22 , including the carrier openings  30  which establish fluid communication between the pump housing interior  4  and the nozzle chamber  29 . 
     In the first fluid flow direction operational mode of operation ( FIGS. 7A and 7B ) of the reversible jet pump  1 , power fluid  72  is pumped downwardly through the tubing string  58  and the jet pump assembly  10 , respectively. Accordingly, as particularly illustrated in  FIG. 7B , the power fluid  72  flows through the proximal carrier head bore  12  of the proximal carrier head  11  and the converging nozzle bore  27 , the nozzle tip  28  and the nozzle chamber  29 , respectively, of the carrier nozzle  26 . In the mixing chamber  32 , the power fluid  72  mixes with reservoir fluid  74  and the resulting fluid mixture  76  flows through the distal carrier head bore  51  of the distal carrier head  44 . As illustrated in  FIG. 7A , from the distal carrier head bore  51 , the fluid mixture  76  flows around the spool tip  65  and spool shaft  64  of the pump spool  60  and then through the fluid flow spaces  84  ( FIG. 3 ) in the spool collar  80 , respectively, and then through the pump housing openings  7  in the pump housing  2  and into the well annulus  71 , respectively. 
     As illustrated in  FIG. 7B , as the power fluid  72  flows through the converging nozzle bore  27  of the carrier nozzle  26 , the pressure of the power fluid  72  drops substantially as the fluid velocity increases as the fluid is discharged from the nozzle tip  28  into the nozzle chamber  29 . A vacuum, or reduced pressure which is generated after the nozzle tip outlet  28 , and in the mixing chamber  32  by the flowing power fluid  72  is at lower pressure than the pressure of the reservoir fluid  74  in the reservoir fluid flow space  75 . Consequently, the reservoir fluid  74  is drawn from the reservoir fluid flow space  75  into the nozzle chamber  29  through the carrier openings  30 , via the power fluid-generated pressure drop in the mixing chamber  32 , and mixes with the flowing power fluid  72 . forming a fluid mixture  76  which includes the power fluid  72  and the reservoir fluid  74 . As it flows through the mixing chamber  32 , the pressure of the fluid mixture  76  remains low and then increases again as the fluid mixture  76  flows first through the diverging chamber segment  34  of the mixing chamber  32  and then through the distal carrier head bore  51  of the distal carrier head  44 , respectively. As further illustrated in  FIG. 7A , the fluid mixture  76  initially flows from the distal carrier head bore  51  through the fluid flow spaces  84  ( FIG. 3 ) in the spool collar  80  of the pump spool  60 , and then turns outwardly and flows through the pump housing openings  7  in the pump housing  2  and into and through the well annulus  71 , respectively, to the well surface. At the well surface, the hydrocarbons may be separated from the power fluid  72  and the reservoir fluid  74  using techniques which are known by those skilled in the art. 
     Due to the drop in pressure of the reservoir fluid  74  in the reservoir fluid flow space  75 , caused by flow of the power fluid  72  from the nozzle tip  28  and through the nozzle chamber  29  and mixing chamber  32 , respectively, reservoir fluid  74  flows from the fluid flow space  75  into the nozzle chamber  29  through the carrier openings  30 . In the straight chamber segment  33  of the mixing chamber  32 , the reservoir fluid  74  mixes with the power fluid  72  and forms the fluid mixture  76 . Consequently, reservoir fluid  74  continues to flow from the well through the suction ports  8  into the fluid flow space  75  in the pump housing interior  4 . Throughout operation of the reversible operation jet pump  1  in the first fluid flow direction operational mode, the velocity head, or downward pressure of the flowing power fluid  72 , along with the weight of the jet pump assembly  10 , maintains the jet pump assembly  10  deployed in place in the pump housing  2 . 
     As the fluid mixture  76  flows from the distal carrier head bore  51  of the distal carrier head  44  through the fluid flow spaces  84  in the spool collar  80 , the spool shaft  64  of the pump spool  60  acts as a flow splitter which facilitates uniform, smooth and even flow of the fluid mixture  76  through the spool collar  80  throughout the circumference of the pump spool  60 . The curved surfaces of the spool body  63  direct the fluid mixture  76  in a continuously smooth, approximately linear, non-turbulent and gradually outward fluid flow path from the straight flow path through the fluid flow spaces  84  in the spool collar  80  and then to the outward flow path through the pump housing openings  7  in the pump housing  2 , respectively, and into the well annulus  71 . Thus, the combined effects of the spool shaft  64  and the spool body  63  reduce or minimize turbulent or uneven flow of the fluid mixture  76 , facilitating steady flow of a large volume of the fluid mixture  76  through the well annulus  71  to the well surface. This expedient together with large suction ports located in the housing wall  3  provides a substantially greater capacity for fluid flow within the jet pump  1  for a given cross-sectional area for the jet pump than can be achieved using conventional pump designs. Consequently, a substantially greater volume of flowing fluid and a substantial reduction in power fluid pump horsepower and in jet pump erosion can be achieved within a given pump cross-sectional area for efficient removal of the reservoir fluid  74  from the well. 
     In some applications, the reservoir fluid  74  may carry sand and/or other particulate matter or corrosives which may have a tendency to abrade or corrode the well casing  70  as the fluid mixture  76  which contains the reservoir fluid  74  is ejected from the pump housing openings  7  into the well annulus  71  and as it flows through the well annulus  71  to the well surface. In such applications, therefore, it may be desirable to operate the reversible operation jet pump  1  in the second fluid flow direction operational mode in which the reservoir fluid  74  is pumped to the well surface after it flows through the jet pump  1  instead of through the well annulus  71 . Accordingly, as illustrated in  FIG. 8A , the carrier  22  is configured in the second orientation in the jet pump assembly  10  such that the carrier nozzle  26  accommodates upward flow of the fluid mixture  76  (which includes the power fluid  72  and the reservoir fluid  74 ) through the jet pump assembly  10 . 
     Reservoir fluid  74  initially flows from the well into the pump housing interior  4  through the suction ports  8  into the reservoir fluid flow space  75  and surrounds the carrier  22 . Power fluid  72  is pumped downwardly through the well annulus  71 . The power fluid  72  flows from the well annulus  71  through the pump housing openings  7  and turns upwardly and flows through the fluid flow spaces  84  ( FIG. 3 ) in the spool collar  80 , respectively, into the distal carrier head bore  51  of the distal carrier head  44 . From the distal carrier head bore  51 , the power fluid  72  flows upwardly through the converging nozzle bore  27  and is discharged from the nozzle tip  28  into the nozzle chamber  29 , respectively, of the carrier nozzle  26 . 
     As illustrated in  FIG. 8B , due to the resulting fluid pressure drop in the mixing chamber  32 , and other jet flow phenomenon, reservoir fluid  74  is drawn from the reservoir fluid flow space  75  in the pump housing interior  4  through the carrier openings  30  and into the nozzle chamber  29 , respectively. The power fluid  72  and the reservoir fluid  74  mix to form the fluid mixture  76 , which flows upwardly through the mixing chamber  32 , the proximal carrier head bore  12  of the proximal carrier head  11  and the tubing string  58 , respectively, to the well surface. As the reservoir fluid  74  is drawn via the power fluid-generated pressure drop from the reservoir fluid flow space  75  through the carrier openings  30  into the nozzle chamber  29 , additional reservoir fluid  74  continues to flow upwardly from the well through the suction ports  8  into the reservoir fluid flow space  75 . Throughout flow of the fluid mixture  76  upwardly through the jet pump assembly  10  and the tubing string  58 , respectively, to the well surface, the power fluid pressure head acts equally in all directions upon the jet pump assembly, and along with the weight of the jet pump assembly and the force required to push the power fluid through the carrier nozzle  26 , reacting downwardly against the surface of the pump spool  60 , along with the pump mass and the seal friction to retain the jet pump assembly  10  in place in the pump housing  2 . 
     Referring next to  FIGS. 9-11  of the drawings, it will be appreciated by those skilled in the art that when it is deployed in either the first fluid flow direction operational mode ( FIG. 7A ) or the second fluid flow direction operational mode ( FIG. 8A ), the jet pump assembly  10  can be selectively removed from the pump housing interior  4  of the pump housing  2  while the pump housing  2  remains deployed on the tubing string  58  in the well casing  70 . This expedient facilitates cleaning, maintenance and/or replacement of the jet pump assembly  10 , re-orientation of the carrier  22  to facilitate reverse flow through the jet pump assembly  10 , and/or clear access to the pump housing, interior  4  and downhole elements of the well through the pump housing interior  4  at clearance matching the I.D. of the tubing for cleaning, maintenance, etc. of the downhole elements of the well below the level of the pump housing  2 . Accordingly, when the jet pump assembly  10  is deployed in the first fluid flow direction operational mode ( FIG. 7A ) for jet pump assembly retrieval, power fluid  72  is initially pumped downwardly through the well annulus  71  and flows through the pump housing openings  7  in the pump housing  2  and the fluid flow spaces  84  in the spool collar  80 , respectively. The power fluid  72  flows upwardly through the distal carrier head bore  51  in the distal carrier head  44 , the mixing chamber  32  and the carrier openings  30 , respectively, and is discharged into the reservoir fluid flow space  75  in the pump housing interior  4 . From the reservoir fluid flow space  75 , the power fluid  72  flows downwardly through the suction ports  8  in the pump housing  2  and is discharged into the downhole portion of the well at the distal seal retaining collar  79 , creating a jet propulsion effect. Pressure builds up against a one-way check valve (standing valve  102 , illustrated in  FIG. 11 ) mounted below packer  100  and the jet pump assembly  10  to prevent flow of the fluid deeper into the well beyond the check valve. Continuous flow of power fluid  72  below the jet pump  1  maintains fluid pressure which pushes the jet pump assembly  10  upwardly in the pump housing  2 , as illustrated in  FIGS. 10 and 11 , and through the tubing string  58  to the well surface. 
     It will be appreciated by those skilled in the art that under circumstances in which the jet pump assembly  10  cannot be retrieved by circulation of the power fluid  72  as in the second fluid flow direction operational mode, as described above for the first fluid flow direction operational mode. a conventional slick line or wire line (not illustrated) can be attached to the proximal carrier head  11  and used to retrieve the jet pump assembly  10  through the tubing string  58 . Additionally, the orientation of the carrier  22  in the jet pump assembly  10  can be changed to facilitate flow of the fluid mixture  76  which includes the reservoir fluid  74  to the well surface through the well annulus  71 , as was heretofore described with respect to  FIG. 7A , or through the jet pump assembly  10 , as was heretofore described with respect to  FIG. 8A . The same components of the jet pump assembly  10  can be used for flow of the reservoir fluid  74  in either fluid flow direction operational mode. The reversible operation jet pump  1  is amenable to use of top and/or bottom standing valves. 
     Referring again to  FIG. 9  of the drawings, it will be further appreciated by those skilled in the art that the high-capacity flow capability of the reversible jet pump  1  is enabled by the flow-directing capabilities of the suction ports  8  in the pump housing wall  3 , the pump spool  60  in the jet pump assembly  10  and fabrication of a pump housing  2  having a pump housing interior  4  with an ID (inner diameter) which matches the ID of the tubing string  58 . Accordingly, the reversible jet pump  1  maximizes reservoir fluid-removing capability without sacrificing optimum production of hydrocarbons from the well and access to the well for cleaning and maintenance. In contrast, conventional designs for pumps used to remove reservoir fluid from a well typically have much smaller suction and discharge passages since they must be confined to the cross-sectional area of the I.D. of the pump housing, which restricts the flow capability of the pumps and compromises the reservoir fluid-removing efficiency of the pumps in order to remain within the operational constraints imposed by the desired hydrocarbon production capability and cleaning and maintenance requirements of the well. 
     In the science and engineering field of hydraulics, the flow of fluids has been studied rigorously for almost two centuries. Dependable and often evolved empirical mathematical formulas exist for fluid flow in pipes, tubes, valves, and various obstacles and fittings. In a downhole jet pump application, there is always limited room for flow of the magnitude required for economical well production, especially since the production fluid has to reverse direction up to 180 degrees in operation. As jet pumps have evolved, the outside diameter of the housing closely mimics that of the production tubing, and in some cases is even less. In consideration of jet pump flow, both production fluid and reservoir fluid must independently move in opposite directions within the space of the internal diameter of the pump housing. Regardless of the various flow paths and port designs, cross-sectional flow area is restricted. 
     Hydraulic design practice teaches that the smaller the flow passage, the greater the pressure drop with respect to passage length. The well-known basic Darcy&#39;s formula for pressure head loss states that:
 
 h   L   =f ( L/D )( v   2 /2 g ),
 
where
 
h L =Static Pressure Head Loss D=Pipe Internal Diameter
 
f=Friction Factor v=Mean Velocity of Flow
 
L=Length of Pipe g=Gravitational Accel.
 
     In downhole artificial lift jet pump applications, the jet pump assembly  1  is utilized inside a hollow cylinder, the jet pump housing  2 . The jet pump housing  2  is attached to a tubing string or production tubing  58 . The tubing string  58 , and hence the jet pump assembly  1 , is lowered into a well (not illustrated) which is defined geometrically by the well casing  70 . The well casing  70  and tubing string  58  are placed concentrically. Standards within the industry establish the size of the well annulus  71  between the well casing  70  and the tubing string  58  or jet pump housing  2 . As described elsewhere herein, the well annulus  71  is used by the jet pump assembly  1  and/or the surface pump (not illustrated) to convey power fluid  72 , or a fluid mixture  76  of power fluid  72  and reservoir fluid  74 , in association with the lifting operation. 
     By definition, a jet pump functions by very high fluid velocities. These velocities are much higher than those generated by other conventional pump designs. 
     In downhole operations there are always numerous concerns, in addition to the prior discussion of below-pump maintenance access, which can significantly affect well performance and serviceable life. Among these are degree of solid contaminants, corrosives, entrained gasses within the reservoir fluid, reservoir fluid pressures, scale buildup, and integrity of the casing. Three major operating factors potentially exacerbated by the use of jet pumps are consumption of excess power by the surface power fluid pump, erosion and/or cavitation of jet pump components, and erosive effects from jet pump output on the casing surface. 
     The power consumption of the power fluid surface pump is largely governed by the efficiency of the jet pump assembly  1 . Generation of power fluid pressure must be sufficient to 1) push power fluid mixed with reservoir fluid through the constricted carrier nozzle  26  and mixing chamber  32 , 2) generate enough pressure differential within the reservoir fluid  74  to cause suction flow to the mixing chamber  32 , and 3) provide adequate pressure to lift the fluid mixture  76  to the well surface through the well annulus  71 . 
     The one established industry-wide geometrical constant in the jet pump design is the configuration of the carrier nozzle  26  with the mixing chamber  32 . Beyond this standard, the arrangement of the diffuser, suction ports  8 , and pump housing  2  may be arranged for maximizing flow efficiency in terms of flow port sizes and degree of streamlining, or the minimizing of abrupt direction changes. In historical and conventional jet pump designs, pressure and suction ports compete for space within the area of inside diameter of the pump housing. The objective of the discharge port, or diffuser, is to reduce the fluid high velocity generated in the mixing chamber  32  for enhanced control of flow up the well annulus  71  and of the damaging effects of impingement upon the wall of the well casing  70 . Greater velocity reduction requires greater cross-sectional flow area, and this infringes on the cross-sectional flow area requirements of the suction ports  8 . After the power fluid  72  is pushed through the carrier nozzle  26 , suction action is a secondary function of the jet pump  1 . The drawing-in of reservoir fluid  74  to the mixing chamber  32  must be sufficient to affect reservoir fluid  74  which is deep within the well, through the standing valve  102  ( FIG. 11 ). Application of the Darcy formula as above indicates that losses are proportional to the squared term of velocity. Pressure losses, and hence, required surface pump power, are sensitive to port size and length.  FIGS. 1, 4, 7A, 8A and 9  illustrate suction ports  8  in the pump housing wall  3 , thus removed and expanded from the housing interior  4 , allowing for maximum spacing, or flow area, for each of the jet pump outlet and suction flows. In this design, both flow areas will be considerably larger than if both remained conventionally within the housing interior  4 , allowing for reduced flow velocity, and hence, power fluid pump power requirement. 
     As noted above, jet pumps inherently operate at high fluid flow velocities. This characteristic renders the jet pump components sensitive to erosion. In addition, the geometry of downhole jet pump systems necessarily includes fluid flow turns and other shape interruptions to preferred streamlined laminar flow. This general high velocity flow irregularity tends to exacerbate erosion to the pump components, and this is accelerated by entrained solids and gaseous contaminants in the fluid. 
     Cavitation is caused by the constant stretching and compression of the fluid as it flows around turns and over path obstacles in the jet pump. Fluids inherently contain entrained gasses and solid particles. During the stressing of the fluid, at occurrences of low pressure the gas can coalesce and appear as bubbles. As they are carried elsewhere to higher pressure areas, the bubbles implode against the pump surface, causing material removal. Reduced fluid velocity and improved flow streamlining reduce cavitation tendencies. 
     The well casing in a well is typically considered a permanent fixture and cannot readily be removed. Care is taken to protect the inside diameter surface of the casing. High velocity output from a jet pump in close proximity to the casing could be erosive to the casing. Hence, jet pump housings are conventionally equal in size to the production tubing, leaving as much annular space to the casing as possible. The design of the jet pump  1  which is described herein may utilize an undulating outside diameter of the pump housing  2 . This design accomplishes both objectives of generation of large suction ports  8 , which are disposed outside the diameter of the pump housing interior  4 , and outlet ports, or pump housing openings  7 , which are spaced away from the well casing  70  as well as evenly-spaced around the periphery of the pump housing  2  for less concentrated flow into the well  71  annulus and against the well casing  70 . 
     While illustrative embodiments of the disclosure have been described above, it will be recognized and understood that various modifications can be made and the appended claims are intended to cover all such modifications which may fall within the spirit and scope of the disclosure.