U.S. patent application number 13/412196 was filed with the patent office on 2012-09-06 for method and apparatus for fluid pumping.
Invention is credited to Leonard C. Sotz, John Van Krevel.
Application Number | 20120224977 13/412196 |
Document ID | / |
Family ID | 46753415 |
Filed Date | 2012-09-06 |
United States Patent
Application |
20120224977 |
Kind Code |
A1 |
Sotz; Leonard C. ; et
al. |
September 6, 2012 |
Method and Apparatus for Fluid Pumping
Abstract
A fluid balanced hydraulic pump has a support tower that can be
mounted over a well. At least one cylinder assembly is pivotally
mounted within the support tower. A prime mover provides hydraulic
fluid to the at least one cylinder assembly through a wedge spool
control valve that provides precise speed control with minimal
maintenance requirements. Stroke speed can be easily and quickly
adjusted without the need for expensive, troublesome or complicated
electronic equipment.
Inventors: |
Sotz; Leonard C.; (Valley
City, OH) ; Van Krevel; John; (Dublin, OH) |
Family ID: |
46753415 |
Appl. No.: |
13/412196 |
Filed: |
March 5, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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61449273 |
Mar 4, 2011 |
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Current U.S.
Class: |
417/18 |
Current CPC
Class: |
F04B 47/04 20130101;
F04B 7/0007 20130101; F04B 7/0015 20130101; F04B 47/08
20130101 |
Class at
Publication: |
417/18 |
International
Class: |
F04B 49/02 20060101
F04B049/02 |
Claims
1. A reciprocating pumping apparatus for pumping fluids from a well
comprising: a. a support frame mounted to said well; b. at least
one hydraulic cylinder assembly mounted within said support frame
in substantially axial alignment with said well; c. a hydraulic
pump for supplying hydraulic fluid to said at least one hydraulic
cylinder assembly; d. a wedge spool control valve disposed between
said hydraulic pump and said at least one hydraulic cylinder
assembly, e. an upper switch disposed in said support frame,
wherein said upper switch stops pumping by said hydraulic pump when
said at least one cylinder assembly is retracted a predetermined
distance; and f. a lower switch disposed in said support frame,
wherein said lower switch commences pumping by said hydraulic pump
when said at least one cylinder assembly is extended a
predetermined distance.
Description
STATEMENTS AS TO THE RIGHTS TO THE INVENTION MADE UNDER FEDERALLY
SPONSORED RESEARCH AND DEVELOPMENT
[0001] NONE
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention pertains to a hydraulic pumping unit.
More particularly, the present invention pertains to a hydraulic
pumping unit that provides precise rod speed control with minimal
maintenance requirements.
[0004] 2. Brief Description of the Prior Art
[0005] Liquid-producing subterranean reservoirs all have some level
of energy or potential, frequently referred to as "reservoir
pressure" that will force fluid (liquid, gas or a mixture) to areas
of lower energy or potential. If a well penetrates such a
reservoir, and if the pressure inside such a well is decreased
below the reservoir pressure, fluids will feed into the well from
said formation. However, depending on the depth of the reservoir
and density of the fluid(s), the reservoir may not have sufficient
reservoir pressure to push the fluid to the surface. The deeper the
well, or the heavier the fluid(s), the higher the reservoir
potential that is required to push such fluid(s) to the
surface.
[0006] Many hydrocarbon producing reservoirs have sufficient
potential to naturally produce oil and gas (which are relatively
light, compared to water) during the early stages of production.
However, as a well continues to produce, reservoir pressure will
often decrease as a reservoir depletes. Further, in many
reservoirs, formation water will eventually encroach into the
wellbore, causing the lifting requirements to be much greater than
for just oil and/or gas. Either or both of these conditions can
cause production from a well to decline, or possibly even cease
entirely.
[0007] As a result of the foregoing, artificial means are often
used to continue or increase the flow of liquids (such as crude
oil, water or a mix of oil and water) from subterranean
reservoir(s) to the earth's surface. As noted above, such
"artificial lift" can be required when insufficient reservoir
pressure exists to lift produced fluids to the surface in a well.
Artificial lift can also be employed in flowing wells to increase
the flow rate above what would occur naturally.
[0008] Although numerous different means of artificial lift exist,
one common type involves the use of a mechanical device known as a
"rod pump" inside a well. Such rod pumps, which are well known to
those having skill in the art, are typically elongate cylinders
with both fixed and moveable elements. Such rod pumps are designed
to be installed down-hole inside of wells, at or near the depth of
the reservoir(s) from which production is obtained, to gather
fluids from below and lift said fluids within the wells to the
surface. In many instances, such down-hole pumps have a barrel
equipped with two ball check valves: a stationary valve near the
bottom of said barrel, and a traveling valve that moves up and
down. As reservoir fluids enter a well from a down-hole
reservoir(s), the down-hole pump lifts such fluids from said
subterranean reservoir(s) to the surface within said well.
[0009] Rod pump systems generally comprise a reciprocating
down-hole pump situated within a well at or near a subterranean
reservoir, an above-ground drive mechanism at the earth's surface,
and a length of elongate cylindrical rods (frequently referred to
as "sucker rods") connecting said down-hole pump to said surface
drive mechanism in said well. In many conventional installations,
said surface drive mechanism comprises a pump-jack (also sometimes
referred to as a pumping unit, horsehead pump, rocking horse, beam
pump, or jack pump) that converts rotary motion (from an electric
motor or internal combustion engine, for example) to a
reciprocating vertical motion in order to drive a reciprocating
down-hole pump via the sucker rods. Such pump-jacks generally
exhibit a characteristic nodding motion.
[0010] Although very common, conventional pump-jacks and other
types of surface drive mechanisms suffer from a number of
significant shortcomings. Said surface drive mechanisms can be
large, cumbersome and difficult to install in many instances.
Further, such conventional surface drive mechanisms are typically
complicated, and expensive to manufacture, operate and
maintain.
[0011] Thus, there is a need for a pumping apparatus having a
surface drive mechanism that is relatively inexpensive, durable and
simple to operate. The hydraulic pumping apparatus should provide
precise rod speed control with minimal maintenance requirements,
while permitting stroke speed to be easily and quickly adjusted
without the need for expensive, troublesome or complicated
electronic equipment.
SUMMARY OF THE PRESENT INVENTION
[0012] The present invention comprises a hydraulic pumping
apparatus having an improved surface drive mechanism. By way of
illustration and not limitation, the present invention is described
herein as a hydraulic pumping apparatus installed on a well for
pumping fluids from subterranean formations. However, it is to be
observed that the hydraulic pumping apparatus of the present
invention, and components thereof, can be used in many different
applications involving the pumping of fluid(s) beyond the
particular embodiment described herein.
[0013] In a preferred embodiment, the hydraulic pumping apparatus
of the present invention comprises an elongate tower assembly that
can be mounted at the surface of a well. Said tower assembly
provides a rigid frame for supporting at least one hydraulic
cylinder assembly that is oriented substantially parallel to said
tower assembly. In the preferred embodiment, said elongate tower
assembly (and the at least one hydraulic cylinder assembly
supported therein) are mounted in substantially axial alignment
over said well at the earth's surface. Said at least one hydraulic
cylinder assembly is connected to a bridle assembly attached to a
polished rod; said polished rod is, in turn, connected to a length
of interconnected sucker rods that extend into said well. A
down-hole pump mechanism is mounted near the bottom of said well
and is attached to the distal end of said sucker rods.
[0014] Said at least one hydraulic cylinder assembly can be
beneficially mounted to said elongate tower assembly using a
self-centering pivot mounting assembly. Said self-centering pivot
mounting assembly ensures that said at least one hydraulic cylinder
assembly finds the center of gravity, thereby preventing unwanted
side loading on said at least one cylinder assembly.
[0015] A prime mover assembly provides hydraulic fluid used to
actuate said at least one hydraulic cylinder assembly. Hoses or
other conduits connect said prime mover to a wedge spool valve
disposed between said prime mover and said at least one cylinder
assembly. Said wedge spool valve can be used to control the
stroking of said at least one hydraulic cylinder assembly and, in
turn, the reciprocation of said sucker rods in and out of said
well.
[0016] The hydraulic pumping apparatus of the present invention is
inexpensive, durable and simple to operate. Further, the hydraulic
pumping apparatus of the present invention has a small footprint
and can be directly mounted to wells having shallow to medium
depths or, alternatively, skid supported for wells extending to
deeper depths. The hydraulic pumping apparatus of the present
invention further provides for precise rod speed control with
minimal maintenance requirements. Stroke speed can be easily and
quickly adjusted without the need for expensive, troublesome or
complicated electronic equipment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The foregoing summary, as well as the following detailed
description of the preferred embodiments, is better understood when
read in conjunction with the appended drawings. For the purpose of
illustrating the invention, the drawings show certain preferred
embodiments. It is understood, however, that the invention is not
limited to the specific methods and devices disclosed. Further,
dimensions, materials and part names are provided for illustration
purposes only and not limitation.
[0018] FIG. 1 depicts a front perspective view of the support tower
of the hydraulic pumping apparatus of the present invention.
[0019] FIG. 2 depicts a front perspective view of the support tower
of the hydraulic pumping apparatus of the present invention
including an optional support base.
[0020] FIG. 3 depicts a front view of the hydraulic pumping
apparatus of the present invention installed on a well.
[0021] FIG. 4 depicts a side view of the support tower of the
hydraulic pumping apparatus of the present invention installed on a
well.
[0022] FIG. 5 depicts a rear view of the hydraulic pumping
apparatus of the present invention installed on a well.
[0023] FIG. 6 depicts a side sectional view of the wedge spool
control valve of the present invention.
[0024] FIG. 7 depicts a side view of the distal end of the wedge
spool member of the wedge spool control valve of the present
invention.
[0025] FIG. 8 depicts and end view of the distal end of the wedge
spool member of the wedge spool control valve of the present
invention.
[0026] FIG. 9 depicts a detailed view of the highlighted area shown
in FIG. 6.
[0027] FIG. 10 depicts a sectional view of the wedge spool control
valve of the present invention along line 10-10 of FIG. 9.
[0028] FIGS. 11 through 14 depict sequential side sectional views
of operation of the wedge spool control valve of the present
invention.
[0029] FIG. 15 depicts a side sectional view of a double seal
system for the cylinder rod assembly of the present invention.
[0030] FIG. 16 depicts a side sectional view of a double seal
system and fluid drain mechanism for the cylinder rod assembly of
the present invention.
[0031] FIG. 17 depicts a side view of the self-centering cylinder
mounting assembly of the present invention.
[0032] FIG. 18 depicts a side sectional view of a cylindrical fluid
reservoir of the present invention.
[0033] FIG. 19 depicts a side sectional view of a zero restriction
check valve assembly of the present invention.
[0034] FIG. 20 depicts a side sectional view of an alternative
embodiment of a zero restriction check valve assembly of the
present invention.
[0035] FIG. 21 depicts a schematic view of one embodiment of a
motor skid of the present invention having an electric regeneration
system.
[0036] FIG. 22 depicts a schematic view of an alternative
embodiment of a motor skid of the present invention not equipped
with an electric regeneration system.
[0037] FIG. 23 depicts a schematic view of one embodiment of a
motor skid of the present invention having an internal combustion
engine.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
[0038] Referring to the drawings, FIG. 1 depicts a front
perspective view of support tower assembly 200 of hydraulic pumping
apparatus 10 of the present invention. Elongate support tower
assembly 200 is capable of being mounted to the upper end of a well
that extends into the earth's crust. Said tower assembly 200 has
substantially planar upper plate member 201 having optional central
aperture 205, lower substantially planar plate member 202 having
cut-out section 203 and elongate column support members 204
extending between said upper and lower plate members. Support tower
assembly 200 provides a rigid support frame for supporting at least
one hydraulic cylinder assembly 300. In the preferred embodiment,
said elongate tower assembly 200 (and said at least one hydraulic
cylinder assembly 300 supported therein) are mounted in
substantially axial alignment over a well.
[0039] As depicted in FIG. 1, tandem cylinder assemblies 300 are
mounted within support tower assembly 200. Each of said hydraulic
cylinder assemblies 300 has a barrel 301 and an extendable piston
rod 302 movably disposed in said barrel 301; because said hydraulic
cylinder assemblies 300 are depicted in the retracted position in
FIG. 1, piston rods 302 are not fully visible in FIG. 1. Cylinder
barrels 301 are attached to upper plate member 201. In the
embodiment depicted in FIG. 1, conventional bolted faster means 303
are used to connect said cylinder assemblies 300 to upper plate
member 201; however, it is to be observed that pivot mounting
assemblies depicted in FIG. 17 (described below) can be
beneficially used for mounting said cylinder assemblies.
[0040] Spreader bar or bridle assembly 310 is connected to the
distal end of each piston rod 302. Said bridle assembly 310 is
attached to polished rod 320 using clamp member 321. Polished rod
320 is, in turn, connected to a length of interconnected sucker
rods 322 that extends into a well (not shown in FIG. 1). Although
not depicted in FIG. 1, it is to be understood that said sucker
rods extend into said well, and connect to a down-hole pump
situated at or near subterranean reservoir(s) from which fluid(s)
are to be produced. Stop angle 312 and valve mounting plate 313 can
also be mounted at desired locations within tower support tower
assembly 200.
[0041] FIG. 2 depicts a front perspective view of support tower
assembly 200 of hydraulic pumping apparatus 10 of the present
invention including optional support base assembly 210. Said tower
assembly 200 has substantially planar upper plate member 201 with
optional central aperture 205, lower substantially planar plate
member 202 having cut-out section 203 and elongate column support
members 204 extending between said upper and lower plate members
and providing structural support for tower assembly 200.
[0042] Tandem cylinder assemblies 300 are mounted within support
tower assembly 200. Each of said hydraulic cylinder assemblies 300
has a barrel 301 and an extendable piston rod 302 movably disposed
in said barrel 301. Cylinder barrels 301 are attached to upper
plate member 201 with fasters 303, while the distal ends of piston
rod members 302 are connected to bridle assembly 310.
[0043] Support base assembly 210 has a plurality of adjustable leg
members 211. Each of said leg members 211 further has a
substantially planar foot pad 212 to ensure stability of said
support base assembly. Support base assembly 210 can be used to
provide additional stability and support to tower assembly 200 when
said tower assembly 200 is mounted on a well. In such instances,
support base assembly 210 prevents all loading from being placed on
a well equipped with hydraulic pumping apparatus 10, and instead
transfers much of said loading (especially axial loading) to
support base assembly 210. Although said support base assembly is
depicted as having three leg members 211 (i.e., a tripod), it is to
be observed that configurations having different numbers of leg
members can also be used. Further, tie rods or other similar
structural supports can be added as may be required.
[0044] FIG. 3 depicts a front view of hydraulic pumping apparatus
of the present invention installed on a well 20 having wellhead 22
and flow lines 21. Tower assembly 200 has substantially planar
upper plate member 201, lower substantially planar plate member 202
and elongate column support members 204 extending between said
upper and lower plate members and providing structural support for
tower assembly 200.
[0045] Tandem cylinder assemblies 300 are mounted within support
tower assembly 200 in substantially parallel orientation. Each of
said hydraulic cylinder assemblies 300 has a barrel 301 and an
extendable piston rod 302 movably disposed in said barrel 301. As
depicted in FIG. 3, cylinder barrels 301 are attached to upper
plate member 201 with fasters 303, while the distal ends of piston
rod members 302 are connected to bridle assembly 310. Bridle
assembly 310 is attached to polished rod 320 using clamp member
321.
[0046] Polished rod 320 is movably disposed through dynamically
sealing stuffing box 220 situated over well 20, and extends into
wellhead 22 in a manner known to those having skill in the art.
Although not shown in FIG. 3, polished rod 320 is connected to a
length of interconnected sucker rods as described above which
extend in said well to a down-hole reciprocating rod pump. Prime
mover assembly 400 is connected to support tower assembly 200 via
hydraulic hose 410.
[0047] As hydraulic cylinder assemblies 300 are actuated, bridle
assembly 310 can be raised and lowered within tower assembly 200.
Such raising and lowering of bridle assembly 310 imparts a
reciprocating motion to polished rod 320 (and attached components)
within well 20. Stuffing box 220 provides a dynamic seal against
polished rod 320, causing pumped well fluids to exit said well via
flow lines 21, rather than out the top of wellhead 22. Upper
electrical switch 350 and lower electrical switch 340 are disposed
within said tower assembly at predetermined locations.
[0048] FIG. 4 depicts a side view hydraulic pumping apparatus of
the present invention installed on a well 20 having wellhead 22.
Tower assembly 200 has substantially planar upper plate member 201,
lower substantially planar plate member 202 and elongate column
support members 204 extending between said upper and lower plate
members and providing structural support for tower assembly 200.
Cylinder assembly 300 is mounted within support tower assembly 200.
Hydraulic cylinder assembly 300 has a barrel 301 and an extendable
piston rod 302 movably disposed in said barrel 301. Upper switch
350 and lower switch 340 are disposed within said tower assembly at
predetermined locations; in the preferred embodiment said switches
350 and 340 are electrical switches, although it is to be observed
that other types of switches may be used.
[0049] Cylinder barrel 301 is attached to upper plate member 201
with fastener 303, while the distal end of piston rod member 302 is
connected to bridle assembly 310. Bridle assembly 310 is attached
to polished rod 320 using clamp member 321. Bridle assembly 310 has
push plate 311 that extends outward from said bridle assembly 310.
Polished rod 320 is movably disposed through dynamically sealing
stuffing box 220 situated over well 20, and extends into wellhead
22 in a manner known to those having skill in the art. Hydraulic
fluid supply line 410 provides a conduit for receiving hydraulic
fluid from a hydraulic pump, such as included within a prime mover
assembly (for example, prime mover assembly 400 depicted in FIG.
3).
[0050] FIG. 5 depicts a rear view of hydraulic pumping apparatus
depicted in FIG. 4. Hydraulic fluid supply line 410 connects from a
hydraulic pump or other source of hydraulic fluid to a controller
assembly 100 having substantially vertical spool member 110
extending therefrom. Upper electrical switch 350 and lower
electrical switch 340 are disposed within said tower assembly at
predetermined locations.
[0051] As depicted in FIG. 5, push plate 311 of bridle assembly 310
is in contact with said spool member 110. Controller assembly
outlet line 411 is a conduit (such as a hose, tube or the like)
that connects controller assembly 100 to hydraulic junction
assembly 412. Cylinder supply lines 413 extend from said hydraulic
junction assembly 412 to hydraulic cylinder assemblies 300 in order
to supply hydraulic fluid to said cylinder assemblies. Relief lines
414 also connect to cylinder assemblies 300 to provide for relief
or bleeding of pressure from said cylinder assemblies.
[0052] FIG. 17 depicts a side view of a self-centering cylinder
mounting assembly 330 of the present invention, which can be used
to pivotally mount cylinder assemblies 300 to tower assembly 200
having upper plate member 201 and support columns 204 instead of
fasteners 303 depicted in FIG. 1. Cylinder extension 331 extends
through an aperture in upper plate member 201, and has downward
facing partially-spherical member 333 having rounded lower surface
and retention collar member 334. Rounded member 333 is movably
disposed within generally concave bowl member 333. Said
self-centering pivot mounting assembly 330 ensures that hydraulic
cylinder assemblies 300 automatically find the center of gravity
over a well (such as well 20 in FIG. 5) thereby preventing unwanted
side loading on said cylinder assemblies 300.
[0053] FIG. 6 depicts a side sectional view of the wedge spool
control valve assembly 100 of the present invention. Said wedge
spool control valve assembly 100 can control the stroking of said
hydraulic cylinder assemblies and, in turn, the reciprocation of
sucker rods in and out of said well, and the function of the
down-hole pump connected to said sucker rods, all as more fully
described herein.
[0054] Wedge spool control valve assembly 100 comprises spool valve
body 101 defining central flow bore 102 and bypass flow bore 103.
In the preferred embodiment, central flow bore extension 104
extends below central flow bore 102. Upper flow channel 105 extends
from said central flow bore 102 to bypass flow bore 103, while
lower flow channel 106 extends from flow bore extension 104 to
bypass flow bore 103. Check valve assembly 120 is disposed within
bypass flow bore 103, and is beneficially positioned between upper
flow channel 105 and lower flow channel 106.
[0055] Elongate spool member 110 having upper surface 110a is
slidably received within bearings 107 which, in turn, are disposed
within central flow bore 102. In this manner, elongate spool member
is slidably received within said central flow bore 102 extending
through spool valve body 101. It is to be observed that additional
bearings 107 can be installed within central flow bore 102 to
exceed the number of such bearings as shown in the figures.
[0056] In the preferred embodiment, elongate wedge spool member 110
extends through aligned apertures 113 in substantially parallel
bottom plate member 111 and upper stroke stop member 112. Elongate
spool member 110 has stroke stop collar 114 having increased
diameter that is greater than the diameter of aperture 113 in upper
stroke stop member 112; said stroke stop collar 114 limits upward
movement of elongate spool member 110. The distance between upper
stroke stop member 112 and spool valve body 101 (and, thus, the
travel of elongate spool member 110) can be adjusted using stroke
stop tie rods 115 and adjustment nuts 116.
[0057] FIG. 7 depicts a side view of the bottom portion of elongate
wedge spool member 110 of the wedge spool control valve assembly
100 of the present invention, while FIG. 8 depicts an end view of
bottom end 117 of said wedge spool member 110 of said wedge spool
control valve assembly 100. Referring to FIG. 8, elongate wedge
spool member 110 has a tapered bottom portion culminating in a
substantially flat bottom surface 117. Still referring to FIG. 8,
said tapered section is beneficially formed with flat surfaces 118
on opposing sides of said elongate spool member 110. Such
configuration allows for improved bearing support through an entire
cycle of said wedge spool control valve assembly 100, which in turn
results in a much smoother function and increased life of said
elongate spool member 110 and bearings 107. By contrast, a
conventional conical spool member is not supported on its sides,
thereby causing wear to be exerted on the spool valve body.
[0058] FIG. 9 depicts a detailed view of the highlighted area of
wedge spool valve assembly 100 shown in FIG. 6. As more fully
described below, pressure compensation occurs in this area because
fluid under pressure surrounds said wedge spool member 110 evenly,
thereby allowing free stroking (movement) of said wedge spool
member 110 within central flow bore 102. FIG. 10 depicts a bottom
sectional view of the wedge spool control valve 100 of the present
invention along line 10-10 of FIG. 9. Elongate wedge spool member
110 having bottom surface 117 and opposing flat side surfaces 118
is disposed within bearings 107, which is in turn disposed within
central flow bore 102 in valve body 101. It is to be observed that
bottom surface can have a curved (convex) shape, if desired.
Additionally, it is to be further observed that multiple additional
bearings can also be provided in addition to the number shown in
the drawings. Upper flow channel 105 is connected to said central
flow bore 102.
[0059] FIGS. 11 through 14 depict sequential side sectional views
of operation of the wedge spool control valve assembly 100 of the
present invention. FIG. 11 depicts wedge spool control valve
assembly 100 in the fully open position. As depicted in FIG. 12,
wedge spool control valve assembly 100 is partially closed. FIG. 13
depicts wedge spool control valve assembly 100 closed even further,
while FIG. 14 depicts said wedge spool control valve assembly 100
in the fully closed position.
[0060] A variable frequency drive ("VFD"), typically included as
part of a prime mover assembly (such as the alternate embodiment
skid packages described in FIGS. 21-23 hereof) and connected to a
controller mechanism, can be used to gradually ramp an electric
motor (driving a hydraulic pump) up to operating speed to lessen
mechanical and electrical stress, thereby reducing maintenance and
repair costs and extending the life of the motor and the drive
equipment. Said VFD can be programmed to ramp up the motor much
more gradually and smoothly, and can operate the motor at less than
full speed to decrease wear and tear.
[0061] In operation, wedge spool control valve assembly 100 of the
present invention controls the actuation of hydraulic cylinder
assemblies and, thus, stroking of a down-hole pump. Reference is
made to FIG. 14, depicting elongate spool member 110 in the
downward, fully-closed position. With spool member 110 of the wedge
spool control valve assembly 100 in the downward position, the
lower electric switch (see, switch 340 in FIGS. 5 and 6) is
triggered, signaling the VFD to gradually ramp up power to the
electric motor, or soft start, which drives the hydraulic pump of
the prime mover assembly.
[0062] Hydraulic fluid is pumped through a line from the hydraulic
pump of the prime mover to the wedge spool control valve assembly
100. Hydraulic fluid enters said wedge spool control valve assembly
100 through bypass bore 103. Simultaneously, check valve assembly
120 opens, allowing fluid to continue flowing through bypass bore
103. Fluid flowing through bypass port 103 continues through
line(s) or hose(s) (see, line 411 in FIGS. 4 and 5) connected to
cylinder assemblies, thereby causing said cylinder assemblies to
retract. As said cylinder assemblies retract, bridle assembly 310
will travel upward, removing downward force on wedge spool member
110.
[0063] Hydraulic fluid passes through lower flow channel 106 and
bore extension 104, into central flow bore 102, forcing wedge spool
member 110 in an upward direction. Said hydraulic cylinder
assemblies continue to retract, until upper electric switch (see,
switch 350 in FIGS. 4 and 5). Actuation of such switch signals the
VFD to ramp down power to the electric motor which, in turn, winds
down the hydraulic pump and the flow of fluid from said pump to
said wedge spool control valve 100 and, ultimately, hydraulic
cylinder assemblies.
[0064] With the pumping stopped and the hydraulic cylinder
assemblies retracted a predetermined amount, the down stroke
portion of the cycle commences. As the down stroke portion of the
cycle commences, fluid is forced (by the weight of the rod string
load) down through bypass bore 103. Check valve assembly 120
closes, thereby diverting hydraulic fluid through upper flow
channel 105 and central flow bore 102, as well as bore extension
104 and lower flow channel 106. Said fluid then flows out of wedge
spool control valve assembly, and through a conduit back to a
hydraulic fluid reservoir in prime mover skid.
[0065] As the piston rods of said hydraulic cylinder assemblies
extend, push plate 311 connected to bridle 310, contacts the upper
surface of elongate spool member 110, driving it downward. Said
elongate spool member 110 will gradually restrict the flow of fluid
while simultaneously decreasing the rate of speed until the motion
is almost stopped. The weight of the rod string acts on said wedge
spool member 110 which, in turn, eliminates loading on the pump and
motor.
[0066] If the pumping unit is not equipped with an electrical
regeneration unit, the motor will be turned off until the down
stroke cycle is complete. However, when an electrical regeneration
unit is installed, the motor is switched into reverse until the
down stroke cycle is complete.
[0067] The process repeats itself with bottom switch being
actuated, thereby triggering the VFD to slowly ramp up the electric
motor. In this position, most of the well load is exerted on the
wedge spool. As a result, start up loading on the electric motor is
reduced, thereby reducing electric consumption and shock on the
entire system. From this position, the up stoke portion of the
cycle begins, and the process is repeated.
[0068] The critical variable for operation of the wedge spool
control valve of the present invention is distance (i.e., the
stroke distance of hydraulic cylinders), rather than time as in
with other conventional hydraulic pumping units. As such, the
pumping apparatus of the present invention is not affected by the
rate of speed on the down stroke cycle. When the push plate 311
(see FIGS. 4 and 5) comes in contact with wedge spool member 110,
it ramps down the flow of fluid, then stops the down stroke in the
same position, no matter the down-stroke speed. Other conventional
units have multiple switches on the bottom of the stroke--one to
slow the rate of down stroke speed, and the other to stop and start
the up stroke cycle. Changing of the stroke speed requires
readjustment of the switches, resulting in additional costs and
potential problems that are not a concern with the present
invention
[0069] During normal operating functions, when wedge spool member
110 reaches around (adjustable) the 98% closed position within bore
102 and bore extension 104, push plate 311 has triggered the VFD to
start the up stroke cycle. In the event of a power failure, or if
the unit shuts down for any reason, the spool valve will continue
down until the piston rods of the hydraulic cylinder assemblies
come in contact with rod end caps of said cylinder assemblies,
which in turn bleeds hydraulic pressure from the entire system.
This function adds a significant safety feature to the hydraulic
pump apparatus of the present invention while also reduces the
likelihood of fluid leaks.
[0070] The hydraulic pumping assembly of the present invention can
be adjusted to speeds to as little as 1 stroke per hour. On the
down stroke cycle, electricity supply is turned off. The present
invention virtually eliminates parted rods caused by stuck pump or
rod string due to the constant monitoring of incoming electric
power supply and instantaneous shutdown on low voltage. The present
invention constantly monitors down hole conditions, and promptly
shuts down if an overload occurs thereby greatly reducing tubing
and rod wear. The present invention further adjusts to the well
feed in rate thereby eliminating the need for a timer. The present
invention will automatically restart when the power supply returns
to normal. The rod clamp is adjustable as with conventional
units,
[0071] Both the up and down stroke speeds can be independently
adjusted by the simple turning of a knob or valve which provides
for infinite variable speed control. An optional clean electrical
power regeneration package can be provided. The present invention
is specifically designed to be well tender friendly and simple to
operate; as a result, limited computer skills are required for
operation of said invention
[0072] FIG. 15 depicts a side sectional view of a double seal
system of the present invention, while FIG. 16 depicts a side
sectional view of a double seal system and fluid drain mechanism
for a hydraulic cylinder assembly of the present invention. Other
conventional hydraulic rod pumping tanks and valve spools typically
have only a single hydraulic cylinder rod seal and rod wiper
system. With only a small amount of use, seals invariably start to
wear. Due to high fluid pressure that such seals are subjected to,
fluid often leaks past such seals and into the surrounding
environment, causing unsafe conditions and/or environmental
contamination.
[0073] The double sealing assembly 150 of the present invention
eliminates problems associated with such conventional assemblies.
The double sealing assembly of the present invention can be
utilized in connection with hydraulic cylinder assemblies, and also
with the wedge spool control valve of the present invention.
Referring to FIG. 15, rod 160 is disposed through the double
sealing assembly 150 of the present invention having rod wiper 151.
Most conventional systems have only a single rod seal. Double
sealing assembly 150 of the present invention has outer rod seal
152 and chamber 153 that acts to trap any contaminants that may
pass the rod wiper and outer seal.
[0074] Chamber drain channel 154 extends from said chamber 153 to a
waste container (not pictured); in the preferred embodiment, said
waste container is maintained at ambient (typically atmospheric)
pressure which in turn lets contaminants flush out of said drain
channel 154 and into said waste container (instead of, as with
conventional systems, leaking past the outer rod seals). As a
result, internal high pressure seal 155 is kept free of most
contaminants which in turn prevents contaminants from migrating
inside. This, in turn, greatly increases the life of the cylinder
or valve spool and also the time between servicing. The double
sealing assembly 150 of the present invention allows operations to
continue much longer, even with the main seal worn because the
fluid is captured instead of leaking onto the surroundings. The
double seal system of the present invention lasts many times longer
than standard systems.
[0075] It is to be observed that double sealing assembly 150 of the
present invention can also be utilized in connection with a wedge
spool control valve of the present invention. Specifically, said
double sealing assembly can be utilized in connection with seals
associated with tapered wedge spool member 110, thereby increasing
the life of such seals and, accordingly, the operating life of
wedge spool control valve of the present invention.
[0076] FIG. 16 depicts a side sectional view of a double seal
system and fluid drain mechanism for a hydraulic cylinder assembly
300 of the present invention having outer rod seal 171. Chamber
drain channel 175 extends from said chamber 174, having upper seals
173 and lower seals 172, to a collection container (not pictured)
via drain line 176. In the preferred embodiment, said collection
container is maintained at ambient (typically atmospheric) pressure
which in turn lets fluid flush out of said drain channel 175 and
into said collection container (instead of, as with conventional
systems, leaking into the surrounding environment).
[0077] FIG. 18 depicts a side sectional view of a cylindrical
aluminum fluid reservoir 50 of the present invention. In the
preferred embodiment, said cylindrical aluminum fluid tank 50 of
the present invention has removable clamp-on bottom 51, bottom
drain fitting 52, removable clamp-on top 53, fluid inlet 54, tower
cylinder air line fitting 55, desiccant 56, cylindrical aluminum
tank body 57, low fluid shut down switch 58, outlet fitting 59,
closing ring clamp 60, gasket 61 and internal baffles 62. Fluid
tank 50 is very easy to clean, will not rust, dissipates heat much
more efficiently than conventional tanks. Hydraulic fluid remains
clean and cool, thereby lasting much longer than in conventional
reservoirs. In the preferred embodiment, said desiccant has a
1/16'' bleed hole, thereby permitting a very small amount of air
change during the up and down cycles. This keeps a tremendous
amount of moisture and contaminants out of the system, resulting in
the fluid and components lasting much longer than conventional
units.
[0078] FIG. 19 depicts a side sectional view of a zero restriction
check valve assembly 80 of the present invention which can be used
in connection with the hydraulic pump included within the prime
mover assembly of the present invention. On the up stroke cycle,
the motor and pump draw fluid from a fluid reservoir, through inlet
port 81 which opens ball 82 to allow fluid to flow freely through
port 83 and to a pump. This action also closes the ball 84 to the
valve seat that to leads to a fluid return tank 85.
[0079] On the down stroke cycle, the regeneration unit and the VFD
are programmed to reverse the electric motor to 0 cycles. The
weight of the well string forces hydraulic fluid back through the
pump, turning the motor in reverse and generating electricity
which, in turn, goes back into the electrical grid. As fluid flows
through port 83, fluid pressure will close ball 82 and open ball
84, which allows fluid to pass through a cooler and/or filter (not
shown on FIG. 19) and, ultimately, into a fluid tank.
[0080] FIG. 20 depicts a side sectional view of an embodiment of a
zero restriction check valve assembly 70 of the present invention.
Said zero restriction check valve has valve body 71, fitting 72
(typically, SAE, JIC, NPTF, or other); ball 73 (which can be
beneficially constructed of plastic), plug with stop pin 74 and
curved seating surfaces 75. The zero restriction check valve
assembly 70 has no springs, sharp corners or other
surfaces/restrictions to impede fluid flow. The design reduced
eddies in flow patterns causing cavitation and pump-damaging gas
bubbles. Ball 73 moves easily within said valve.
[0081] FIG. 21 depicts a schematic view of one embodiment of a
prime mover/motor skid 380 of the present invention having an
electrical regeneration system. VFD 381 controls power to a motor
and is controlled by a 2-switch mechanism. Said VFD 381 can be
programmed to shut down when the following happens: high fluid
temperature, low fluid level (leak), low incoming voltage with auto
restart when power returns to normal, high hydraulic pressure
caused by stuck rods, and/or down stream problems (frozen lines,
closed valve or other). Said VFD can be programmed to operate at
double the cycles (RPM) of the motor design with no adverse
effects. In the preferred embodiment, said VFD has a potentiometer
that controls the up stroke speed from 0 to 200% of motor rated
speed.
[0082] Referring to FIG. 21, said motor skid 380 further includes
the following:
[0083] 381--Electrical regenerative mounted with VFD. On the down
stroke cycle, the flow control 387 (below) is used as a back up so
the down speed is controlled in the event that the unit fails.
Fluid is forced through the pump; turning it in reverse so the pump
now acts as a hydraulic motor that in turn drives the electric
motor in reverse thereby sending electrical current back into the
electrical grid. Fluid is diverted by zero restriction check valve
assembly (396), also shown in detail in FIG. 19.
[0084] 382--Electric motor
[0085] 383--Hydraulic pump
[0086] 384--Check valve to keeps the pump and motor from turning in
reverse.
[0087] 385--Hydraulic line to the tower
[0088] 386--Control wire from the tower to the VFD
[0089] 387--Flow control valve. Controls the down stroke speed from
max.
[0090] 389--Cooler
[0091] 390--Filter
[0092] 391--Reservoir
[0093] 392--Desiccant
[0094] 393--Air line to the top of the cylinders
[0095] 394--Base (tank)
[0096] 395--Base drain
[0097] 396--Zero Restriction Check Valve and Electrical
Regeneration (See, FIG. 19).
[0098] FIG. 22 depicts a schematic view of an alternative
embodiment of a prime mover/motor skid 360 of the present invention
having a non-electrical regeneration system. VFD 361 controls power
to a motor and is controlled by a 2-switch mechanism. Said VFD can
be programmed to shut down when the following happens: high fluid
temperature, low fluid level (leak), low incoming voltage with auto
restart when power returns to normal, high hydraulic pressure
caused by stuck rods, and/or down stream problems (frozen lines,
closed valve or other). Said VFD can be programmed to operate at
double the cycles (RPM) of the motor design with no adverse
effects. In the preferred embodiment, said VFD has a potentiometer
that controls the up stroke speed from 0 to 200% of motor rated
speed.
[0099] Referring to FIG. 22, said motor skid 360 further includes
the following:
[0100] 362--Electric motor
[0101] 363--Hydraulic pump
[0102] 364--Check valve to prevent the pump and motor from turning
in reverse
[0103] 365--Hydraulic line to the tower.
[0104] 366--Control wire from the tower to VFD
[0105] 367--Flow control valve to control the down stroke speed
from max. to stop.
[0106] 368--Electric valve. Said electric valve opens on the down
stroke so fluid from the cylinders feeds back into the reservoir
and closes on the up stroke so fluid from the pump retracts the
cylinders.
[0107] 369--Cooler
[0108] 370--Filter
[0109] 371--Reservoir
[0110] 372--Desiccant
[0111] 373--Air line to the top of the cylinders
[0112] 374--Base (tank)
[0113] 375--Base drain
[0114] FIG. 23 depicts a schematic view of one embodiment of a
prime mover/motor skid assembly 270 of the present invention having
an internal combustion engine. At the start of the up stroke cycle,
the bottom tower switch (340 in FIG. 4) is actuated at the down
stroke of cylinder assemblies 300.
[0115] Actuation of said switch ramps up the engine governor.
Simultaneously, valves 278 and 286 slowly close, controlled by a
timer mechanism that eliminates any shock on the up start. The up
speed is controlled by predetermined setting of the governor. When
the stroke gets close to the top, a switch (350 in FIG. 4) actuates
controls that act to ramp the governor down to idle and
simultaneously slowly opens valves 278 and 286. The down speed is
controlled by the flow control valve 287. Valve 287 is also used as
a brake that can lock the stroke in any location desired for
tending to or performing work on a well.
[0116] Now continuing the down stroke, as in above, the down stroke
continues until the wedge spool control valve 110 ramps down the
speed and the down stroke length is reached. Hydraulic pressure can
still be maintained as to prevent a sudden shock of pressure at the
start of the up cycle. On the down stroke cycle, check valve 274
keeps pressure off valve 278 and pump 273. Valve 277 is depicted as
a redundant check valve that isolates any back pressure on the
pump. Valve 278 beneficially allows the engine to idle free of any
pressure.
[0117] Electric valves 278 and 286 are normally open. In case of
engine failure, on either the up or down stroke, at any position,
the stroke will automatically go down, such that the spool push
plate 311 comes contacts wedge spool 110, thereby gently ramping
down the speed. The process continues until the end of the wedge
spool valve's stroke is reached and all the hydraulic pressure is
bled from the system, with hydraulic cylinders fully extended down.
This process eliminates any danger of accidently causing injury
from high hydraulic pressure.
[0118] Referring to FIG. 23, said motor skid 270 further includes
the following components:
[0119] 271--Enclosure for engine governor, timer, relays and valve
controls
[0120] 272--Internal Combustion engine
[0121] 273--Hydraulic pump
[0122] 274--Check valve
[0123] 275--Hydraulic line to the tower
[0124] 276--Control wire from the tower to the VFD
[0125] 277--Check valve
[0126] 278--Hydraulic fluid and pressure unloading valve
[0127] 279--Cooler
[0128] 280--Filter
[0129] 281--Reservoir
[0130] 282--Desiccant
[0131] 283--Air line to the top of the cylinders
[0132] 284--Base (tank)
[0133] 285--Base drain
[0134] 286--Downstoke cycle return valve
[0135] 287--Flow control valve
[0136] In addition to the embodiments depicted in FIGS. 21 through
23, it is to be observed that an optional controller system can
also be employed to control function of the various components of
the present invention including, without limitation, components of
prime mover/motor skid packages discussed herein. Said controller
system can include a central processor for collecting data from
sensors and sending signals to certain components to control
operation of said components. In some applications, certain
communication functions of the components of the present invention
can be accomplished through the use of wireless communication and
associated automation.
[0137] The above-described invention has a number of particular
features that should preferably be employed in combination,
although each is useful separately without departure from the scope
of the invention. While the preferred embodiment of the present
invention is shown and described herein, it will be understood that
the invention may be embodied otherwise than herein specifically
illustrated or described, and that certain changes in form and
arrangement of parts and the specific manner of practicing the
invention may be made within the underlying idea or principles of
the invention.
* * * * *