U.S. patent application number 10/711832 was filed with the patent office on 2006-03-02 for method and apparatus for removing liquids from wells.
Invention is credited to Alvin Liknes.
Application Number | 20060045767 10/711832 |
Document ID | / |
Family ID | 46321647 |
Filed Date | 2006-03-02 |
United States Patent
Application |
20060045767 |
Kind Code |
A1 |
Liknes; Alvin |
March 2, 2006 |
Method And Apparatus For Removing Liquids From Wells
Abstract
A method and pump apparatus for removing formation fluids from a
"liquid loaded" gas well is provided. The pump apparatus is adapted
to be positioned downhole a well and is hydraulically operated to
lift formation fluid, such as water from the well to "unload" the
well and reestablish gas production. The pump apparatus includes a
pump body, a hydraulic head connected to the pump body, and a
displacement plunger operated by the hydraulic head to reciprocate
the displacement plunger within pump body to draw-in and displace
formation fluid from the pump apparatus. The pump apparatus is a
fluid displacement type pump and has a low power consumption
affording use of the pump apparatus at even the most remote well
locations. Additionally, a method of operating the pump apparatus
is provided
Inventors: |
Liknes; Alvin; (Calgary,
CA) |
Correspondence
Address: |
STEPHEN J. LEWELLYN
933 OLEANDER WAY SOUTH
SUITE 3
SOUTH PASADENA
FL
33707
US
|
Family ID: |
46321647 |
Appl. No.: |
10/711832 |
Filed: |
October 7, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10926424 |
Aug 26, 2004 |
|
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10711832 |
Oct 7, 2004 |
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Current U.S.
Class: |
417/415 ;
417/552 |
Current CPC
Class: |
F04B 53/12 20130101 |
Class at
Publication: |
417/415 ;
417/552 |
International
Class: |
F04B 35/04 20060101
F04B035/04; F04B 53/12 20060101 F04B053/12 |
Claims
1. A hydraulic fluid displacement pump comprising: a pump body
having an exterior surface and defining an axial bore comprising a
first chamber and a second chamber which are separated by a
diametrically reduced section of said axial bore, said pump body
further defining at least one gas vent extending from said exterior
surface into said first chamber, a fluid inlet port extending from
said exterior into said second chamber, and a fluid discharge port
extending from said exterior thereof into said second chamber; a
hydraulic head attached to said pump body; a displacement plunger,
said displacement plunger extending from said hydraulic head
through said axial bore and which is operated by said hydraulic
head to be reciprocated within said axial bore, said displacement
plunger defining a vent passage through a distal end thereof; a
hydraulic circuit comprising a prime mover, a hydraulic valve
assembly, and a pair of hydraulic cylinders which are fitted with
floating pistons, wherein said hydraulic circuit is connected to
said hydraulic head; a fluid discharge conduit connected to said
fluid discharge port; a first check valve inline with said fluid
discharge conduit; a second check valve connected to said fluid
inlet port; and a lift tube, wherein said lift tube is in fluid
communication with said discharge conduit.
2. The hydraulic fluid displacement pump of claim 1, wherein said
hydraulic circuit utilizes two separate working fluids.
3. The hydraulic fluid displacement pump of claim 2, wherein one
working fluid is of a lower specific gravity than the other working
fluid.
4. The hydraulic fluid displacement pump of claim 3, wherein one of
the two working fluids is diesel fuel.
5. The hydraulic fluid displacement pump of claim 1, wherein said
first chamber and said second chamber are of diameters which are
greater then the diameter of said displacement plunger.
6. The hydraulic fluid displacement pump of claim 1, further
comprising: a casing having an interior volume, said casing
enclosing said pump body and said hydraulic head within said
interior volume, said casing defining a first fluid passage in
fluid communication with said interior volume at a first end
thereof and a second fluid passage in fluid communication with said
interior volume at a second end thereof; and wherein said lift tube
is attached to said casing and is sealed from said interior volume
thereof.
7. The hydraulic fluid displacement pump of claim 1, further
comprising a control system operatively connected to said hydraulic
circuit to control the reciprocation of said displacement
plunger.
8. The hydraulic fluid displacement pump of claim 1, wherein said
first chamber and said second chamber are fluidically sealed from
one another by said displacement plunger extending through said
diametrically reduced section.
9. A hydraulic fluid displacement pump comprising: a pump body
having an exterior surface, said pump body defining an axial bore,
a fluid inlet port extending said exterior into said axial bore, a
fluid discharge port extending from said exterior surface into said
axial bore, and a vent port extending from said exterior surface
into said axial bore; a hydraulic head attached to said pump body
and positioned within said casing; a displacement plunger which
extends from said hydraulic head through said axial bore and which
is operated by said hydraulic head to be reciprocated within said
axial bore; a hydraulic circuit comprising a prime mover, a
hydraulic valve assembly, and a pair of hydraulic cylinders which
are fitted with floating pistons, wherein said hydraulic circuit is
attached to said hydraulic head; a fluid discharge conduit
connected to said fluid discharge port; a first check valve inline
with said fluid discharge conduit; a second check valve connected
to said fluid inlet port; a lift tube, wherein said lift tube is in
fluid communication with said discharge conduit; and a vent valve
attached to said vent port.
10. The hydraulic fluid displacement pump of claim 9, wherein said
hydraulic circuit utilizes two separate working fluids.
11. The hydraulic fluid displacement pump of claim 10, wherein one
working fluid is of a lower specific gravity than the other working
fluid.
12. The hydraulic fluid displacement pump of claim 11, wherein one
of the two working fluids is diesel fuel.
13. The hydraulic fluid displacement pump of claim 9, further
comprising a control system operatively connected to said hydraulic
circuit to control the reciprocation of said displacement
plunger.
14. The hydraulic fluid displacement pump of claim 9, wherein said
vent valve is a normally closed valve and is operated to open based
upon a predetermined fluid pressure within said hydraulic
circuit.
15. The hydraulic fluid displacement pump of claim 9, further
comprising: a casing having an interior volume and enclosing said
pump body and said hydraulic head within said interior volume, said
casing defining a first fluid passage in fluid communication with
said interior volume at a first end thereof and a second fluid
passage in fluid communication with said interior volume at a
second end thereof; and wherein said lift tube is attached to said
casing and is sealed from said interior volume thereof.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation in part (CIP) of
co-pending application Ser. No. 10/926,424 filed Aug. 26, 2004, the
entirety of which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to methods and
systems for lifting fluids from a well. More particularly, relating
to a method and apparatus for removing formation fluid, such as
water from a low production gas well to reduce static pressure
within the well created by the formation fluid, thereby increasing
production of gas from the well.
DISCUSSION OF THE PRIOR ART
[0003] Many gas wells experience decreased gas production over the
service time of the well, and some eventually cease gas production
completely. Factors causing this problem include declining
reservoir pressure and gas velocities, and increased liquid
production. The increased liquid production can results in a column
of liquid to accumulating at the bottom of the well, preventing
reservoir fluids (gas) from entering the wellbore. This
accumulation of liquid is called "liquid loading of the well".
[0004] There are many systems available to restore a well that is
"liquid loaded" back to flow production, such as a siphon string
(or velocity string), a plunger lift, a pump jack, and a
submersible pump.
[0005] A siphon string is essentially a small diameter tubing
string that is lowered into the production string of a well. The
siphon string provides a reduced cross-sectional flow area which
increase the gas velocity in the tubing. The higher gas velocity at
the bottom of tubing provides more transport energy to lift fluid
up out of the well. Liquid no longer accumulates at the bottom of
the well, and production is sustained. Siphon strings are very
difficult to size properly so that the gas velocity meets or
exceeds a minimum or critical velocity to prevent the well from
loading up. The process of determining the correct size of the
tubing string is well described by Turner et al. in "Analysis and
Prediction of Minimum Flow Rate for the Continuous Removal of
Liquid from Gas Wells"; J. Pet. Tech (September 1969)
1475-1481.
[0006] A plunger lift is an artificial-lift method principally used
in gas wells to "unload" relatively small volumes of liquid. An
automated system is employed to control the well on an intermittent
flow regime. When the well is shut-in, a plunger is dropped down
the production string and then when the control system opens the
well for production, the plunger and a column of fluid are carried
up the tubing string. A surface receiving mechanism detects the
plunger when it arrives at the surface and, through the control
system, prepares for the next cycle. One deficiency of a plunger
lift system in the amount of time required for each cycle of the
system. Typically gas wells are medium to deep wells and plunger
must travel a great distance up and down the well to lift
fluid.
[0007] A pump jack is another artificial lift method and basically
includes a plunger pump submerged into the well below the volume of
water and is actuated by a rod string that extends to the surface,
which is reciprocated by a prime mover at the surface. A pump jack
is an old fashion system and is prone to wear resulting in down
time required to make necessary repairs.
[0008] The use of a submersible pump is yet an additional method of
"unloading" the well, which involves placing the pump at the bottom
hole and positively pumping the fluid to the surface of to "unload"
the well. Submersible pumps are limited to the depth of the well
and become less efficient in operation the deeper the well is.
Additionally, electrical submersible pumps are typically used which
requires the drop-in of an electric control line and electric power
line.
[0009] While the above described systems operate as intended, there
exists a need for a more efficient method and apparatus for
"unloading" a well, as such the method and apparatus of the instant
invention provides such a method and apparatus which is more
efficient, less costly to operate, experiences less wear, and has a
reduced cycle time.
SUMMARY OF THE INVENTION
[0010] In accordance with the present invention, an apparatus and
method for efficiently removing fluid from a well is provided. The
apparatus is relatively inexpensive to manufacture as it
incorporates readily available components and is inexpensive to
operate due to a low electrical load requirement, which can be met
by using solar power systems or by a small electric generator. The
low power requirement make the instant invention very conducive for
operation with wells that do not have access to wired electrical
power.
[0011] In one embodiment, the apparatus essentially includes a pump
body having an exterior surface and an axial bore comprising a
first chamber and a second chamber which are separated by a
diametrically reduced section of the axial bore. The pump body
further includes at least one gas vent which extends from the
exterior surface of the pump body into the first chamber, a fluid
inlet port extending from the exterior into the second chamber, and
a fluid discharge port extending from the exterior surface and into
the second chamber. A hydraulic head is attached to the pump body
and a displacement plunger extends from the hydraulic head through
the axial bore. A hydraulic circuit is attached to the hydraulic
head and is operated to control reciprocation of the displacement
plunger within the axial bore by the hydraulic head. A vent passage
extends through a distal end of the displacement plunger for
venting gas therethrough from the second chamber into the first
chamber and then finally through the gas vent of the pump body. A
fluid discharge conduit is connected to the fluid discharge port
and includes a first check valve connected inline therewith
allowing fluid to be discharge in only one direction from the
second chamber out of the discharge port and into a lift tube,
which is connected to the fluid discharge conduit. A second check
valve is connected to the fluid inlet port for allowing formation
fluid to flow in one direction into the first chamber of the pump
body.
[0012] In a second embodiment, the apparatus essentially includes a
pump body having an exterior surface and an axial bore. A fluid
inlet port extends from the exterior surface of the pump body into
the axial bore, a fluid discharge port extends from the exterior
surface into the axial bore, and a vent port extends from the
exterior surface into said axial bore. A hydraulic head is attached
to the pump body and a displacement plunger extends from the
hydraulic head through the axial bore. A hydraulic circuit attached
to the hydraulic head and operated the same to reciprocate the
displacement plunger within the axial bore. A fluid discharge
conduit is connected to the fluid discharge port and a first check
valve is connected inline therewith to allow fluid to flow in only
one direction out of the fluid discharge port and into a lift tube
connected the fluid discharge conduit. A second check valve
connected to said fluid inlet port to allow formation fluid to flow
in one direction into the axial bore and a vent valve is attached
to the vent port for venting gas therethrough and out of the axial
bore.
[0013] There has thus been outlined, rather broadly, the more
important features of the invention in order that the detailed
description thereof that follows may be better understood and in
order that the present contribution to the art may be better
appreciated.
[0014] Numerous objects, features and advantages of the present
invention will be readily apparent to those of ordinary skill in
the art upon a reading of the following detailed description of
presently preferred, but nonetheless illustrative, embodiments of
the present invention when taken in conjunction with the
accompanying drawings. The invention is capable of other
embodiments and of being practiced and carried out in various ways.
Also, it is to be understood that the phraseology and terminology
employed herein are for the purpose of descriptions and should not
be regarded as limiting.
[0015] As such, those skilled in the art will appreciate that the
conception, upon which this disclosure is based, may readily be
utilized as a basis for the designing of other structures, methods
and systems for carrying out the several purposes of the present
invention. It is important, therefore, that the claims be regarded
as including such equivalent constructions insofar as they do not
depart from the spirit and scope of the present invention.
[0016] For a better understanding of the invention, its operating
advantages and the specific objects attained by its uses, reference
should be had to the accompanying drawings and descriptive matter
in which there is illustrated preferred embodiments of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The invention will be better understood and objects other
than those set forth above will become apparent when consideration
is given to the following detailed description thereof. Such
description makes reference to the annexed drawings wherein:
[0018] FIG. 1a is a diagrammatic view of the preferred embodiment
of the method and apparatus for removing fluids from wells
constructed in accordance with the principles of the present
invention;
[0019] FIG. 1b is a detailed diagrammatic view of the hydraulic
control system;
[0020] FIG. 2a is a side elevation view of a first embodiment of a
pump apparatus of the present invention shown in a first
position;
[0021] FIG. 2b is a side elevation view of the pump apparatus of
FIG. 2a shown in a second position;
[0022] FIG. 3a is a side elevation view of a second embodiment of
the pump apparatus of the present invention shown in a first
position; and
[0023] FIG. 3b is a side elevation view of the pump apparatus of
FIG. 3a shown in a second position.
[0024] The same reference numerals refer to the same parts
throughout the various figures.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] Referring now to the drawings, and particularly to FIGS.
1a-3b, a preferred embodiment of the pump apparatus 10 is
illustrated. With reference to FIG. 1a, the pumping apparatus 10 is
employed to lift formation fluid 12 from the well 14 to "unload"
the well and restore it back to flow production. The formation
fluid 12 can be water, oil or any other liquid gas mixture which is
present downhole the well 14 to be pumped from one location to
another. In addition, while the pump apparatus 10 is shown to be
lifting the formation fluid 12 from a conventional gas well 14, the
pump apparatus 10 will work as well in any other environment where
its particular features would be beneficial.
[0026] The pump apparatus 10 essentially includes a pump body 18, a
hydraulic head 20 connected to the pump body, a reciprocating
displacement plunger 22 connected to and operated by the hydraulic
head 20 to reciprocate within the pump body to draw-in formation
fluid 12 and displace it from the pump body to the surface of the
well 14.
[0027] The hydraulic head 20 is connected to a hydraulic circuit 24
having a prime mover 26 which is positioned at the surface of the
well 14. The prime mover 26 can be of any know device for
establishing pressure within the hydraulic lines of a hydraulic
system, such as a pump. Due to the design of the pump apparatus 10,
the power requirements to operate the pump apparatus are very low
and can be supplied by one of a numerous sources, such as a small
portable electric generator or preferable, a solar energy
conversion system 15.
[0028] A more detailed explanation of the hydraulic circuit 24 can
be had with reference to FIG. 1b. The hydraulic circuit 24 includes
a prime mover 26, a hydraulic valve assembly 27, and a pair
hydraulic cylinders 29a and 29b that are fitted with floating
pistons. The prime mover 26 is connected to the hydraulic valve
assembly 27 and the hydraulic cylinders 29a and 29b are connected
in parallel between the hydraulic valve assembly and the hydraulic
head 20. The hydraulic valve assembly 27 is operative, manually or
by automation to control the sequential pressurization and
depressurization of each hydraulic cylinder 29a and 29b by the
prime mover 26. The hydraulic circuit 24 utilizes two separate
working fluids, one working fluid is utilized on the prime mover 26
side of the hydraulic cylinders 29a and 29b and the second working
fluid is utilized on the hydraulic head 20 side of the hydraulic
cylinders. The second working fluid is ideally a low viscosity
fluid, such as diesel fuel. Diesel fuel is desired as the second
working fluid because it has a low viscosity at low temperatures
and also has some lubrication characteristics that allow for
minimum wear on various components of the pump 10. The use a low
viscosity fluid as the second working fluid allows the control
lines 70 or capillary lines to be of a lesser diameter, thus
reducing expense and weight of the system.
[0029] The design of the hydraulic pump 10 does not require the
circulation of the working fluid for the operation of the pump, as
such the hydraulic cylinders 29a and 29b which are fitted with
floating pistons seal the first working fluid, such as the
hydraulic oil used in the prime mover 26 from the second working
fluid used to reciprocate the displacement plunger 22.
Additionally, the hydraulic cylinders 29a and 29b are constructed
of a sufficient volume to compensate for temperature variations
within the second working fluid.
[0030] Referring now to FIG. 2a, the construction of the pump
apparatus 10 will be described in more detail. The pump body 18 has
an axial bore 28 defining a first chamber 30, a diametrically
reduced section 32, and a second chamber 34. At least one gas vent
port 36 is formed through the side wall 38 of the pump body 18 and
into the first chamber 30. Preferably, the gas vent port 36 is
formed through the side wall 38 normal to the axial bore 28. A
fluid in-let port 40 is formed through the side wall 38 of the pump
body 18 and into the second chamber 34. Preferably, the fluid
in-let port 40 is formed through the side wall 38 normal to the
axial bore 28. A fluid discharge port 42 is also formed through the
pump body 18 and into the second chamber 34. Preferably, the fluid
discharge port 42 is formed axially through an end 44 the pump body
18.
[0031] The hydraulic head 20 is attached to the pump body 18
opposite of end 44 and the displacement plunger 22 extends from the
hydraulic head into the axial bore 28 through the first chamber 30,
the diametrically reduced section 32 and into the second chamber
34. The displacement plunger 22 seals the first chamber 30 from the
second chamber 34 when passed through the diametrically reduced
section 32. A seal 46 is positioned between the displacement
plunger 22 and the diametrically reduced section 32 to insure the
first chamber 30 and the second chamber 34 remained sealed from on
another. Preferable the stroke of the displacement plunger 22 is
about equal to the length of the second chamber 34. The stroke of
the displacement plunger 22 is such, when in a fully retracted
position the end 48 thereof is flush with the diametrically reduced
section 32 on the second chamber 34 side, as illustrated in FIG.
2a. When the displacement plunger 22 is in a fully extended
position, the end 48 is in close tolerance to the end 50 of the
second chamber 34.
[0032] Preferably, the diameter of the displacement plunger 22 is
less then the diameter of the axial bore 28 so that the
displacement plunger does not contact the surface of the axial bore
to reduce wear and to eliminate the need to lubricate the
displacement plunger.
[0033] A vent passage 52 is formed through the end 48 of the
displacement plunger 22 such that fluid, gas or air is allowed to
pass through the end 48 and out of the gas vent port 36 when the
displacement plunger is in the fully retracted position as shown in
FIG. 2a.
[0034] A fluid discharge conduit 54 is attached to the fluid
discharge port 42 and includes a first check valve 56 connected
in-line therewith to allow formation fluid 12 displaced from the
pump body 18 by the displacement pump to only flow in one direction
through the discharge conduit and to prevent backflow of the
formation fluid into the pump body, which has already been
displaced by the displacement plunger. A lift tube 58 is provided
and is in connected to the discharge conduit 54 to carry the
formation fluid 12 to the surface of the well 14. A second check
valve 60 is connected to the fluid in-let port 40 and allows
formation fluid only flow into the pump body 18 through the fluid
in-let port.
[0035] Additionally, the pump apparatus 10 can include a casing 62
enclosing the pump body 18, the hydraulic head 20, and any other
element of the pump apparatus as so desired within an interior
volume 64. Preferable, all of the elements are enclosed by the
casing 62 and positioned within the interior volume thereof. The
casing 62 including a pair of fluid passages 66 which are formed
through the sidewall 68 of the casing placing the interior volume
64 of the casing in fluid communication with the well 14. Most
preferably, the pair of fluid passages 66 are formed through the
casing 62 at opposite ends thereof.
[0036] When the casing 62 is included in the pump apparatus 10, the
lift tube 58 is connected to the exterior of the casing and is
sealed from the interior volume 64 thereof, with the fluid
discharge conduit 54 connected to the lift tube and the hydraulic
control lines 70 run down the lift tube and connect to the
hydraulic head 20.
[0037] Referring now to FIGS. 2a and 2b, the pump apparatus 10 is
preferably placed downhole below or about the perforations 72 of
the well 14 and into a column of formation fluid 12. The
displacement plunger 22 is first fully retracted establishing fluid
communication between the first chamber 30 and the second chamber
34 by the vent passage 52 formed into the displacement plunger. In
this position, formation fluid 12 is hydrostatically forced by well
pressure into the pump body 18 through the fluid in-let port 40 and
into the second chamber 34. If any gas is admixed with the
formation fluid 12 it flows from the second chamber 34 through the
vent passage 52 into the first chamber 30 and then out of the gas
vent port 36. The displacement plunger is held in the retracted
position for a predetermined time that is sufficient for a desired
volume of formation fluid 12 to collect within the second chamber
34.
[0038] When the predetermined time as been met, the displacement
plunger 22 is operated by the hydraulic head 20 and is extended
into the second chamber 34. As the displacement plunger 22 travels
into the second chamber 34, the first chamber 30 and the second
chamber are fluidically disconnected and the formation fluid 12
present within the second chamber is displaced by the displacement
plunger out of the fluid discharge port 42, into the fluid
discharge conduit 54, and then into the lift tube 58, where it
travels to the surface of the well 14.
[0039] Once the displacement plunger 22 has completed the stroke,
it is then reset into the retracted position and the cycle is
reinitiated. The pump apparatus 10 is operated in this manner until
enough formation fluid 12 is lifted from the well to "unload" the
well and reestablish gas production from the well.
[0040] Referring now to FIGS. 3a and 3b, a second embodiment of the
pump apparatus 10 is illustrated and will be described. In this
embodiment, the pump apparatus 10 is of the basic construction as
the first embodiment and includes a pump body 18, a hydraulic head
20 connected to the pump body, and a reciprocating displacement
plunger connected to and operated by the hydraulic head 20 to
reciprocate within the pump body to draw-in formation fluid 12 and
displace it from the pump body to the surface of the well 14. The
main difference between the first and second embodiments is the
first chamber 30, the diametrically reduced section 32, and the
second chamber 34 are eliminated in the second embodiment, and a
vent valve is added to control the venting of formation fluid 12
from the pump body 18.
[0041] More particularly in the second embodiment, the pump body 18
has an axial bore 28, a gas vent port 36 formed through the side
wall 38 of pump body, a fluid in-let port 40 formed through the
side wall, and a fluid discharge port 42 formed through the side
wall. Most preferably, the gas vent port 36 is formed through the
side wall 38 normal to the axial bore 28, the fluid in-let port 40
is formed through the side wall 38 normal to the axial bore 28, and
the fluid discharge port 42 is formed axially through an end 44 of
the pump body 18.
[0042] The hydraulic head 20 is attached to the pump body 18
opposite of end 44 and the displacement plunger 22 extends from the
hydraulic head into the axial bore 28. Preferable the stroke of the
displacement plunger 22 is about equal to the length of the axial
bore 28. Most preferably, the diameter of the displacement plunger
22 is less then the diameter of the axial bore 28 so that the
displacement plunger does not contact the surface of the axial bore
to reduce wear and to eliminate the need to lubricate the
displacement plunger.
[0043] A fluid discharge conduit 54 is attached to the fluid
discharge port 42 and includes a first check valve 56 connected
in-line therewith to allow formation fluid 12 displaced from the
pump body 18 by the displacement pump to only flow in one direction
through the discharge conduit and to prevent backflow of the
formation fluid into the pump body.
[0044] A lift tube 58 is provided and is in connected to the
discharge conduit 54 to carry the formation fluid 12 to the surface
of the well 14. A second check valve 60 is connected to the fluid
in-let port 40 and allows formation fluid only flow into the pump
body 18 through the fluid in-let port. A vent valve 74 is attached
to the gas vent port 36 and is operative to control venting of
fluid from the gas vent. Preferably, the vent valve 74 is a
normally closed valve and is operated to open based upon a
predetermined pressure present within the hydraulic circuit 24.
[0045] As in the previous embodiment, the pump apparatus 10 can
also optionally include a casing 62 enclosing the pump body 18, the
hydraulic head 20, and any other element of the pump apparatus as
so desired within an interior volume 64. Preferable, all of the
elements are enclosed by the casing 62 and positioned within the
interior volume thereof. The casing 62 including a pair of fluid
passages 66 which are formed through the sidewall 68 of the casing
placing the interior volume 64 of the casing in fluid communication
with the well 14. Most preferably, the pair of fluid passages 66
are formed through the casing 62 at opposite ends thereof.
[0046] When the casing 62 is included in the pump apparatus 10, the
lift tube 58 is connected to the exterior of the casing and is
sealed from the interior volume 64 thereof, with the fluid
discharge conduit 54 connected to the lift tube and the hydraulic
control lines 70 run down the lift tube and connect to the
hydraulic head 20.
[0047] In operation, the displacement plunger 22 is first set at a
full retracted position for a predetermined time and formation
fluid 12 is allowed to enter the pump body through the fluid in-let
port 40. The hydraulic circuit 24 is pressurized to a predetermined
pressure opening the gas vent port 36 to vent any gas admixed with
the formation fluid drawn into the pump body.
[0048] When the predetermined time is met, the gas vent valve 74 is
isolated and closed, and the displacement plunger 22 is operated by
the hydraulic head 20 and is extended into the axial bore 28. As
the displacement plunger is extended into the axial bore 28, the
formation fluid 12 is displaced by the displacement plunger out of
the fluid discharge port 42, into the fluid discharge conduit 54,
and then into the lift tube 58, where it travels to the surface of
the well 14.
[0049] Once the displacement plunger 22 has completed the stroke,
it is then reset into the retracted position and the cycle is
reinitiated. The pump apparatus 10 is operated in this manner until
enough formation fluid 12 is lifted from the well to "unload" the
well and reestablish gas completion from the well.
[0050] In either embodiment, the operation of the pump apparatus 10
can be a manual control through the incorporation of manually
actuated valves in the hydraulic circuit 24, or preferably, a
programmable logic controller 76 is used and is programmed to
control the operation of hydraulic valve assembly 27. It is
believed that no further discussion of the manual or controller
operation of the pump apparatus is needed as it is in the knowledge
of one of ordinary skill to incorporate such control systems into a
hydraulic circuit to operate a hydraulic plunger.
[0051] A method of removing formation fluids from a well to
"unload" the well is also provided. The method involves the steps
of providing a hydraulically operated fluid displacement pump
connected to a hydraulic circuit, positioning the fluid
displacement pump downhole, operating the fluid displacement pump
intermittently to vent the pump of gas, load the pump with
formation fluid and to discharge the formation fluid to the surface
of the well. The displacement pump comprising any one of the two
above described embodiments.
[0052] A number of embodiments of the present invention have been
described. Nevertheless, it will be understood that various
modifications may be made without departing from the spirit and
scope of the invention. Accordingly, other embodiments are within
the scope of the following claims.
* * * * *