U.S. patent application number 11/762627 was filed with the patent office on 2008-04-17 for downhole oil recovery system and method of use.
Invention is credited to Joe Crawford.
Application Number | 20080087437 11/762627 |
Document ID | / |
Family ID | 39302125 |
Filed Date | 2008-04-17 |
United States Patent
Application |
20080087437 |
Kind Code |
A1 |
Crawford; Joe |
April 17, 2008 |
DOWNHOLE OIL RECOVERY SYSTEM AND METHOD OF USE
Abstract
An improved hydraulic downhole oil recovery system may
incorporate an above ground hydraulic pumping unit and a
submersible, bidirectional, reciprocating downhole hydraulic slave
cylinder-based pumping unit. Water, rather than hydraulic fluid,
may be responsible for actuating the reciprocating downhole pump
unit. The water may be transferred through the system using
seamless, coil tubing.
Inventors: |
Crawford; Joe; (Crane,
TX) |
Correspondence
Address: |
COX SMITH MATTHEWS INCORPORATED
112 EAST PECAN STREET, SUITE 1800
SAN ANTONIO
TX
78205-1521
US
|
Family ID: |
39302125 |
Appl. No.: |
11/762627 |
Filed: |
June 13, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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PCT/US2005/045305 |
Dec 13, 2005 |
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11762627 |
Jun 13, 2007 |
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11010641 |
Dec 13, 2004 |
7165952 |
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PCT/US2005/045305 |
Dec 13, 2005 |
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10945562 |
Sep 20, 2004 |
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11762627 |
Jun 13, 2007 |
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10945530 |
Sep 20, 2004 |
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10945562 |
Sep 20, 2004 |
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10884376 |
Jul 2, 2004 |
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10945530 |
Sep 20, 2004 |
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Current U.S.
Class: |
166/369 ;
166/68 |
Current CPC
Class: |
E21B 43/129
20130101 |
Class at
Publication: |
166/369 ;
166/068 |
International
Class: |
E21B 43/12 20060101
E21B043/12 |
Claims
1. An oil recovery system comprising: a generally hollow production
tube having an interior space; an upstroke reservoir and a
downstroke reservoir disposed in said interior space; a downstroke
powerline in fluid communication with said downstroke reservoir; an
upstroke powerline in fluid communication with said upstroke
reservoir; a power piston disposed in said interior space of said
production tube and in fluid communication with said downstroke
reservoir and said upstroke reservoir; a connecting rod disposed in
said interior space of said production tube and having a first end
attached to said power piston; a production piston being attached
to a second end of said connecting rod; a seal disposed between
said production piston and said power piston; an oil inlet in fluid
communication with an oil reservoir; wherein said seal separates
said downstroke reservoir and said upstroke reservoir from said oil
reservoir disposed in said interior space of said production tube;
wherein said power piston is actuatable over a range of motion
between a first position and a second position by differential
pressure exerted on said power piston by a power fluid; and an oil
inlet valve in fluid communication with said oil inlet.
2. The oil recovery system of claim 1 wherein said downstroke
powerline and said upstroke powerline comprise coil tubing.
3. The oil recovery system of claim 1 wherein said production tube
comprises coil tubing.
4. The oil recovery system of claim 1 wherein said production
piston is disposed at a bottom end of said connecting rod and said
power piston is disposed at a top end of said connecting rod.
5. The oil recovery system of claim 1 wherein said production
piston is disposed at a top end of said connecting rod and said
power piston is disposed at a bottom end of said connecting
rod.
6. The oil recovery system of claim 1 wherein said power fluid
comprises water-based fluid.
7. The oil recovery system of claim 1 wherein said production tube
is removable.
8. The oil recovery system of claim 1 further comprising a surface
pump unit having a sensor wherein said surface pump unit is
connected to said downstroke powerline and said upstroke
powerline.
9. The oil recovery system of claim 1 wherein said upstroke
powerline and said downstroke powerline extend along a length of
said production tube.
10. The oil recovery system of claim 1 wherein said power piston
and said production piston are shaped and sized such that
production fluid is sucked through said oil inlet valve and into a
first oil reservoir upon an upstroke of said power piston.
11. The oil recovery system of claim 1 further comprising a second
oil inlet in fluid communication with a second oil reservoir
located in said interior space of said production tube.
12. The oil recovery system of claim 1 wherein said downstroke
powerline and said upstroke powerline are disposed outside of said
production tube.
13. The oil recovery system of claim 1 wherein said oil inlet is
disposed adjacent to said seal.
14. The oil recovery system of claim 13 further comprising a valve
disposed adjacent to said oil inlet valve.
15. An improved hydraulic downhole oil recovery system, comprising:
elongate, substantially seamless fluid transfer tubes; a hydraulic
surface unit in substantially sealed fluid communication with a
hydraulic surface unit end of said fluid transfer tubes, said
hydraulic surface unit comprising pressurized fluid transfer means
for transferring a pressurized fluid through said fluid transfer
tubes; and a submersible downhole unit, in substantially sealed
fluid communication with said hydraulic surface unit though a
substantially sealed connection with a downhole unit end of said
fluid transfer tubes, said submersible downhole unit comprising: a
power piston and cylinder assembly, a power piston component of
which is actuatable over a range of motion to and between a first
power piston position and a second power piston position by
differential pressure exerted on said power piston by said
pressurized fluid, a connecting rod extending between said power
piston and a production piston and cylinder assembly, a production
piston component of which is actuatable over a range of motion to
and between a first production piston position and a second
production piston position, wherein said connecting rod holds said
power piston and said production piston in a fixed position with
respect to one another, a plurality of valves configured in
relation to a production cylinder portion of said production piston
and cylinder assembly for sequentially and repetitively, upon
actuation of said production piston effecting, in response to said
actuation of said production piston: first drawing production fluid
into a first portion of said production piston and cylinder
assembly and substantially simultaneously ejecting production fluid
from a second portion of said production piston and cylinder
assembly; second drawing production fluids into said second portion
of said production piston and cylinder assembly and substantially,
simultaneously ejecting production fluid from said first portion of
said production piston and cylinder assembly; and third drawing
production fluid into said first portion of said production piston
and cylinder assembly and substantially simultaneously ejecting
production fluid from said second portion of said production piston
and cylinder assembly; a first effluent tube and a second effluent
tube, configured, respectively, for receiving said production fluid
as ejected from said first and second portions of said production
piston and cylinder assembly and conveying said production fluid to
a production fluid collection receptacle; and a hydraulic fluid
comprising water.
16. The system of claim 15 wherein said pressurized fluid comprises
water, at least one-half by volume.
17. The system of claim 15 wherein said connecting rod extends from
said power piston and cylinder assembly to said production piston
and cylinder assembly through an orifice, said orifice having a
margin which is metallic and is sized and shaped to form a
metal-to-metal seal between said connecting rod and said margin of
said orifice.
18. A method of using an improved hydraulic downhole oil recovery
system comprising: selecting a hydraulic downhole oil recovery
system, comprising: elongate, substantially seamless fluid transfer
tubes; a hydraulic surface unit in substantially sealed fluid
communication with a hydraulic surface unit end of said fluid
transfer tubes, said hydraulic surface unit comprising pressurized
fluid transfer means for transferring a pressurized fluid through
said fluid transfer tubes; and a submersible downhole unit, in
substantially sealed fluid communication with said hydraulic
surface unit though a substantially sealed connection with a
downhole unit end of said fluid transfer tubes, said submersible
downhole unit comprising: a power piston and cylinder assembly, a
power piston component of which is actuatable over a range of
motion to and between a first power piston position and a second
power piston position by differential pressure exerted on either
side of said power piston by said pressurized fluid, a connecting
rod extending between said power piston and a production piston and
cylinder assembly, a production piston component of which is
actuatable over a range of motion to and between a fist production
piston position and a second production piston position, wherein
said connecting rod holds said power piston and said production
piston in a fixed position with respect to one another, a plurality
of valves configured in relation to said a production cylinder
portion of said production piston and cylinder assembly for
sequentially and repetitively, upon actuation of said production
piston effecting, in response to said actuation of said production
piston: first drawing production fluid into a first portion of said
production piston and cylinder assembly and substantially
simultaneously ejecting production fluid from a second portion of
said production piston and cylinder assembly; second drawing
production fluids into said second portion of said production
piston and cylinder assembly and substantially, simultaneously
ejecting production fluid from said first portion of said
production piston and cylinder assembly; and third drawing
production fluid into said first portion of said production piston
and cylinder assembly and substantially simultaneously ejecting
production fluid from said second portion of said production piston
and cylinder assembly; a first effluent tube and a second effluent
tube, configured, respectively, for receiving said production fluid
as ejected from said first and second portions of said production
piston and cylinder assemble and conveying said production fluid to
a production fluid collection receptacle; and a hydraulic fluid
comprising water; positioning said hydraulic surface unit
substantially at ground level and near a well bore of an oil well;
positioning said submersible downhole substantially adjacent to a
production zone of said oil well; and actuating said hydraulic
downhole oil recovery system for producing oil from said oil
well.
19. The method of claim 18 wherein said pressurized fluid comprises
water, at least one-half by volume.
20. The method of claim 18 wherein said connecting rod extends from
said power piston and cylinder assembly to said production piston
and cylinder assembly through an orifice, said orifice having a
margin which is metallic and is sized and shaped to form a
metal-to-metal seal between said connecting rod and said margin of
said orifice.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of
PCT/US2005/045305, filed Dec. 13, 2005, which is a
continuation-in-part of U.S. application Ser. No. 11/010,641, filed
Dec. 13, 2004, now U.S. Pat. No. 7,165,952, and this application is
a continuation-in-part of U.S. application Ser. No. 10/945,562,
filed Sep. 20, 2004, which is a continuation-in-part of U.S.
application Ser. No. 10/945,530, filed Sep. 20, 2004, which is a
continuation-in-part of U.S. application Ser. No. 10/884,376, filed
Jul. 2, 2004, the disclosures of all of which are incorporated
herein by reference.
FIELD
[0002] The system described herein generally relates to an improved
hydraulic downhole oil recovery system.
BACKGROUND
[0003] Conventional oil recovery systems are hampered by
limitations on both the depth and volume of oil that can be
recovered. In fact, known oil recovery systems can generally
recover 400 barrels of oil per day, at a depth of 1000 feet, using
full-sized standard surface pumps.
[0004] Conventional oil recovery systems are relatively short-lived
and require a high level of maintenance. Current systems rely on
large, cumbersome parts that are prone to leaking and causing wear
and tear of standard production tubing. In the past, fitting system
components and power fluid tubing within coil tubing has proven to
be too difficult.
[0005] A large portion of the problems associated with known oil
recovery systems come from the secured-production tubing
configuration of those systems. Specifically, reciprocation of the
sucker rod within the production tube causes wear and tear of the
tubing. As a result, leaks often originate within the tubing at the
secured reciprocation location. This leads to both inefficiency and
environmental contamination. Such problems are exaggerated in the
common case of deviated oil wells.
[0006] Common oil recovery systems also present significant
problems at the surface. Surface pumps are loud, cumbersome,
visually offensive, dangerous, and environmentally unfriendly. As
such, restrictions are placed on both where and when these systems
can be used. Prohibitive zoning restrictions are often based on the
way the pumps look, how they sound, and the inconvenience they
cause to people in their proximity. Further, it is widely known in
the art that conventional surface pumps are prone to leaking both
oil and hazardous fumes. As such, environmental concerns are very
high and periodic maintenance is required, while the cost of
operation increases and efficiency decreases.
[0007] Surface pumps are also dangerous; each year, there are
several injuries and deaths that result from the operation of such
pumps. These casualties often involve children who make their way
to the pumps, drawn by curiosity, only to get caught in the moving
parts.
[0008] There is a narrow range of hydraulically operated oil
recovery systems known in the art. For instance, Schulte (U.S. Pat.
No. 5,494,102) discloses a downhole operated pump having a power
piston reciprocated by alternating pressurized hydraulic fluid flow
controlled at the surface by a hydraulic power control system which
quickly reverses the flow direction.
[0009] In view of the limitations and hazards associated with
traditional oil recovery systems, and the defects in those systems,
a great need exists for a system that can operate efficiently and
safely.
EXAMPLES AND SUMMARY
[0010] The present system does away with the limitations of the
prior art. Some embodiments of Applicant's system will be able to
recover 1500 barrels per day, using a fraction of the energy
consumed by conventional systems. Particular embodiments of the
present system may be maintained on solar energy, which is not
feasible with known downhole oil recovery systems. Some embodiments
of Applicant's system provide a much smaller surface unit, with
fewer moving parts, and incorporate coil tubing. As such, the
maintenance and the risk of leaks are reduced. As will be further
discussed, various embodiments of Applicant's system eliminate the
common problems of the prior art through the novel use of coil
production tubing.
[0011] Applicant's system provides a refreshing solution to the
problems mentioned above and avoids the worst characteristics
associated with known surface pumps. Various embodiments of the
present system use only a fraction of the energy required for
standard surface pumps. As such, the present system is much smaller
and quieter, is easily housed and insulated, and greatly reduces
the likelihood of leaks and the need for maintenance. Further, the
present system eliminates the dangers associated with surface pumps
as there are no large, cumbersome moving parts.
[0012] Applicant's system is distinguished from Schulte
specifically in a number of ways. While Schulte teaches an
apparatus having a power piston above the production piston, some
embodiments of the present system provide for a power piston below
the production piston. Such configuration provides greater
efficiency and allows the present system to be operated on much
less energy.
[0013] Schulte teaches a power piston that runs along the well bore
itself. However, some embodiments of the present system provide for
a power piston/production piston configuration whereby each piston
is actuated within a removable tube housing located within the well
bore. This feature provides for a straightforward maintenance or
replacement scheme that is simply not available with devices known
in the art.
[0014] Applicant's system also provides a scheme whereby either the
volume of the power piston or the volume of the production piston
may be changed with respect to one another. As such, the power
piston/production piston ratio may be manipulated to vary the power
fluid/output fluid ratio for different situations. For example, the
size of the power piston may be increased with respect to the
production piston. This scheme will allow the present system to be
operated on an extremely small amount of power. In fact, some
embodiments are thought to operate within the range of solar power
sources. This feature is not available with any known products.
Alternatively, the size of the production piston could be increased
with respect to the power piston. This scheme will allow the
present system to achieve rates of oil production not generally
possible. For example, the present system will be able to produce
approximately 1,500 barrels of oil per day while accepted
limitations fall around 400 barrels of oil per day. As mentioned,
the components are housed in a removable tubing; as such, the power
piston/production piston ratio may be changed in accordance with
changing amounts and depths of available oil.
[0015] Applicant's system further provides a tremendous improvement
in oil production efficiency. Traditional oil well pump devices can
only pump oil to the surface during an upstroke. However, some
embodiments of the present system, through employment of a double
acting pump and a novel component configuration, allow for oil to
be continuously pumped to the surface. That is, oil is sent to the
surface during both the upstroke and the downstroke. Perhaps of
even greater importance, this "double action" is achieved with no
greater expenditure of power. While production is double, energy
consumption remains constant.
[0016] Certain embodiments of the present system incorporate the
use of coil tubing throughout the system. Coil tubing is known in
the industry and is typically used to clean sand from well bores;
however, no known products have been able to incorporate such
tubing to transfer power fluid and provide housing for system
components. Some embodiments of Applicant's system, however,
provide for the novel use of such tubing to transfer power fluid
and house components. This feature makes such embodiments of
Applicant's system particularly useful in deviated oil wells when
compared to presently available products. Through use of coil
tubing, water-based fluid rather than hydraulic fluid, and a unique
combination of system components, various embodiments of
Applicant's system eliminate problems associated with known
recovery systems and provide tremendous progress in view of those
systems.
[0017] Certain embodiments of the present system are further
distinguished over the prior art in general, and the Schulte patent
in particular, by the use of water-based fluid rather than
hydraulic fluid to actuate the downhole reciprocating pump unit.
The substitution of water-based fluid for hydraulic fluid may
appear to be a subtle distinction at first glance. Nevertheless,
the use of water-based fluid in the present system has virtually
eliminated the most common problems associated with presently
proposed but impractical hydraulic recovery systems, including: the
compression of production fluid circulated though the system,
inflexible fluid transfer lines, fluid friction during downhole and
return flow cycles, and fluid viscosity.
[0018] In view of the foregoing, some embodiments of the present
system provide an oil recovery system that pumps oil to the surface
during both its upstroke and its downstroke.
[0019] Various embodiments of the present system provide an oil
recovery system that has a favorable oil production to energy
consumption ratio.
[0020] Various embodiments of the present system provide an oil
recovery system that eliminates conventional tubing wear and
tear.
[0021] Various embodiments of the present system provide an oil
recovery system that eliminates weak tubing link unreliability.
[0022] Various embodiments of the present system provide an oil
recovery system that eliminates surface leaks.
[0023] Various embodiments of the present system provide an oil
recovery system that eliminates pumping unit liability.
[0024] Various embodiments of the present system provide an oil
recovery system that eliminates submersible pump
inefficiencies.
[0025] Various embodiments of the present system provide an oil
recovery system that may be exceptionally useful in deviated oil
wells.
[0026] Various embodiments of the present system provide an oil
recovery system that produces and maintains relatively high volume
lift in relatively low production wells.
[0027] Various embodiments of the present system provide an oil
recovery system that may be used in environmentally sensitive
locations.
[0028] Various embodiments of the present system provide an oil
recovery system that may be safely used in urban environments.
[0029] Various embodiments of the present system provide an oil
recovery system that may be used in corrosive environments.
[0030] Various embodiments of the present system provide an oil
recovery system that may be used in remote locations.
[0031] Various embodiments of the present system provide an oil
recovery system that contains a surface adjustable lift
capacity.
[0032] Various embodiments of the present system provide an oil
recovery system that may be used to recover particularly deep oil
deposits.
[0033] Various embodiments of the present system provide an oil
recovery system that may be powered by solar energy or other
alternative power sources.
[0034] Various embodiments of the present system provide an oil
recovery system that employs the use of coil production tubing.
[0035] Various embodiments of the present system provide an oil
recovery system that maintains its power piston below its
production piston.
[0036] Various embodiments of the present system provide an oil
recovery system that employs the use of pressure controlled surface
pumps.
[0037] Various embodiments of the present system provide an oil
recovery system that requires an exceptionally low amount of
service.
[0038] Various embodiments of the present system provide an oil
recovery system that has an exceptionally long running life.
[0039] As will be discussed in the specification to follow, some
embodiments of the present system involve a pressure-type pump
surface unit. This surface unit is modified to read and react to
pressure measurements during pump cycles so that when pressure
builds past a certain point at the completion of a cycle, the unit
"switches" to begin the next cycle. As mentioned, the surface unit
of the present system is of a pressure-type, and therefore is much
smaller, quieter, and cleaner than standard oil well surface
units.
[0040] The surface unit of the present system is connected to a
downhole apparatus by a pair of hydraulic powerlines. Some
embodiments of the downhole unit of the present system primarily
consist of a power piston, a production piston, a connecting rod,
and a series of inlets, valves, and reservoirs. Operation of the
system is initiated when power fluid is alternatingly pumped
through each powerline, thereby actuating a downhole power piston
between a top position and a bottom position. Specifically, as
fluid is pumped through the upstroke powerline, the fluid volume of
the reservoir below the power piston expands, thereby forcing the
power piston upward. During the following downstroke, fluid is
pumped through the downstroke powerline, and the fluid volume of
the reservoir above the power piston expands, thereby forcing the
power piston downward.
[0041] A connecting rod extends from the power piston to the
production piston. In holding the power piston and production
piston fixed with respect to one another, the connecting rod
traverses both a hydraulic power fluid reservoir and an oil
reservoir. Importantly, the connecting rod, in combination with the
pump barrel, forms a fluid-tight seal between the power fluid
reservoir and the oil reservoir. This feature allows the connecting
rod to actuate between a top position and a down position while
keeping the "dirty" oil environment separate from the "clean" power
fluid environment.
[0042] In some embodiments, the production piston rests along the
top surface of the connecting rod and is actuated between a bottom
position just above the power fluid reservoir and a top position
just below a one-way valve. These one-way valves may be standard
"check" valves as known in the art. That is, each valve may consist
of a loosely seated bearing that rests above a grooved slot. Each
bearing may become unseated, thereby allowing fluid to flow in a
given direction, yet returns to a seated position to prevent
backflow of any fluid.
[0043] In some embodiments, as the production piston is actuated
from a bottom position to a top position, oil is cycled from a
first inlet, positioned below the production piston, to a first
reservoir, positioned between the power fluid reservoir and the
production piston. During this stage, production oil located in a
second reservoir, positioned between the production piston and a
one-way check valve, is forced through the check valve and to the
rest of the system. Specifically, the production piston forces oil
through the check valve. As the production piston begins to lower,
the check valve returns to the seated position, preventing fluid
from returning. This action also creates the vacuum that is
responsible for sucking oil through a second oil inlet into a
second oil reservoir. This process is repeated through a series of
valves until the oil is cycled to the surface.
[0044] In some embodiments, as the production piston is actuated
from a top position to a bottom position, oil is cycled from a
second inlet, positioned above the production piston at the
completion of a downstroke, into a second reservoir, positioned
between the production piston and a one-way check valve. During
this stage, production oil located in the first reservoir,
positioned between the production piston and the power fluid
reservoir, is forced through an adjacent shaft leading from the
first reservoir to a location above the second reservoir and
separated from the first reservoir by a check valve. Said adjacent
shaft also contains its own one-way valve so that fluid only flows
through the shaft during the downstroke, and no backflow is
permitted.
[0045] It is important to note that the general operation and
effectiveness of the present system do not depend on the exact
arrangement of the component parts. Specifically, in some
embodiments, the power piston may be placed below or above the
production fluid reservoirs. It is easily seen that production oil
may still be pumped on both an upstroke and a downstroke, with only
minor changes needed in the arrangement of the system. In each
arrangement, the efficiency of the present system is preserved.
[0046] As mentioned, some embodiments of Applicant's system
circulate a water-based fluid, rather than hydraulic fluid,
throughout the system. This substitution promotes both the novel
design and great efficiency of the present system. More
specifically, the use of water-based fluid provides for a much
greater operating efficiency. That is, typical hydraulic fluid is
compressible and therefore requires significantly more pump strokes
to "pressure up" than a column of water-based fluid. As a result,
the efficiency of hydraulic fluid decreases over any appreciable
distance as its compression causes wasted pump strokes, which
directly translates to lost power. Because some embodiments of the
present system use incompressible water-based fluid, problems
associated with fluid compressibility have been eliminated.
Specifically, power loss is avoided as there is no appreciable loss
in efficiency due to the compression of the circulated production
fluid.
[0047] Other useful embodiments of the present system are thought
to utilize additives that may increase the viscosity of the
water-based hydraulic fluid. Such may involve the use of "oils" to
form emulsions. These embodiments are thought to be particularly
useful in further reducing fluid friction and further improving
operating efficiency.
[0048] However, the benefits associated with the present system do
not end with use of water-based fluid. Further benefits of the
present system may lie in the placement and action of the downhole
pump. In some embodiments, the downhole pump is placed below the
production oil; as such, the surface unit is in a mechanically
superior alignment. That is, the surface unit is responsible for
actuating only the downhole pump, rather than cycling the entire
production string through the production tube. This feature alone,
in conjunction with an efficient surface unit, provides for an
extreme decrease in the energy used during production.
[0049] Devices of the past have not been successful in using coil
tubing, as it has proven too difficult to incorporate such tubing
within the production tube itself. However, Applicant has overcome
that obstacle. Some embodiments of the present system provide for
coil, flexible tubing contained within the production tube that
allows circulation of water-based fluid from the surface to the
downhole pump unit. This feature alone, and particularly in
combination with coil production tubing, allows some embodiments of
the present system to be useful in deviated wells that would
otherwise be inaccessible.
BRIEF DESCRIPTION OF THE DRAWINGS
[0050] Applicant's system may be further understood from a
description of the accompanying drawings, wherein unless otherwise
specified, like reference numerals are intended to depict like
components in the various views.
[0051] FIGS. 1A-1B are cross-sectional views of one embodiment of a
downhole unit of a hydraulic downhole oil recovery system.
[0052] FIGS. 2A-2B are cross-sectional views of one embodiment of a
downhole unit of a hydraulic downhole oil recovery system.
[0053] FIG. 3 is a cross-sectional schematic view of one embodiment
of a downhole oil recovery system as used in connection with an oil
well.
[0054] FIG. 4 is a perspective view of one embodiment of a downhole
unit of a downhole oil recovery system.
[0055] FIGS. 5A-5B are cross-sectional views of the downhole unit
of FIG. 4.
DETAILED DESCRIPTION
[0056] With reference to FIG. 3, a hydraulic downhole oil recovery
system is identified generally by the reference numeral 10. In some
embodiments, system 10 is primarily made of alloy metal and coil
tubing.
[0057] Referring to FIGS. 1A-1B, FIGS. 2A-2B, FIG. 3, FIG. 4 and
FIGS. 5A-5B, system 10 includes surface pump unit 12. Surface pump
unit 12 sends power fluid 14 through upstroke powerline 16 during
one cycle and sends power fluid 14 through downstroke powerline 18
in a following downstroke cycle. Surface pump unit 12 reversibly
engages with powerlines 16 and 18 so as to form a fluid-tight seal,
such seal being formed by standard tube fittings as known in the
art. In some embodiments, surface pump unit 12 is a pressure pump,
modified to contain a "switch off pressure sensor" 13 which reads
the pressure at surface pump unit 12 on both the upstroke and the
downstroke. At the point each stroke is carried out, pressure
increases beyond a preset "switch off" point where sensor 13 sends
a signal to surface pump unit 12 to begin the next stroke. Further,
surface pump unit 12 transfers power fluid 14 by alternating
pressure on both powerline 16 and powerline 18, and such pressure
change may be carried out in a number of ways. Finally, in some
embodiments, power fluid 14 may be a water-based fluid. As
previously discussed in the specification, the use of water-based
fluid in conjunction with system 10 provides its user with a number
of advantages.
[0058] Both upstroke powerline 16 and downstroke powerline 18 may
extend from surface pump unit 12 to a downhole unit 11 and follow
along the length of removable production tube 20. Production tube
20, in some embodiments, reversibly slides along outer shaft 21. In
some embodiments, upstroke powerline 16 and downstroke powerline 18
are comprised of coil production tubing. As previously discussed in
the specification, powerlines made of this material allow some
embodiments of the present system to be particularly useful in
deviated oil wells. Perhaps more importantly, powerlines made of
this material avoid the problems otherwise associated with the use
of particularly long, jointed tubes in a hydraulic powerline
context.
[0059] Upstroke powerline 16 leads to upstroke reservoir 22 and is
connected thereto by upstroke fitting 24. Downstroke powerline 18
leads to downstroke reservoir 26 and is connected thereto by
downstroke fitting 28. In some embodiments, both fitting 24 and
fitting 28 are standard tube fittings as known in the art.
[0060] As surface pump unit 12 sends power fluid 14 through
upstroke powerline 16, power fluid 14 fills upstroke reservoir 22
such that its fluid volume increases, thereby actuating power
piston 30 in an upward direction so that the fluid volume of
downstroke reservoir 26 decreases. Likewise, as surface pump unit
12 sends power fluid 14 through downstroke powerline 18, power
fluid 14 fills downstroke reservoir 26 such that its fluid volume
increases, thereby actuating power piston 30 in a downward
direction, so that the fluid volume of upstroke reservoir 22
decreases.
[0061] Referring to FIGS. 1A-1B, FIGS. 2A-2B, FIG. 4 and FIGS.
5A-5B, power piston 30 is actuated between a top position and a
bottom position, where power piston 30 reaches a position just
above upstroke fitting 24 at the completion of the downstroke in
the bottom position; and where power piston 30 reaches a position
just below downstroke fitting 28 at the completion of the upstroke
in the top position. The pressure change in powerlines 16 and 18,
and resulting fluid volume change in reservoirs 22 and 26,
respectively, is the mechanism responsible for actuating power
piston 30. In some embodiments, power piston 30 is a "spray metal"
plunger, or made of some suitable alloy, and is shaped so as to
form a fluid-tight fit with removable production tube 20.
[0062] Connecting rod 32 is attached to power piston 30 and extends
therefrom. Connecting rod 32 is of such length that connecting rod
32 extends beyond pump barrel seal 38 during both the downstroke
and the upstroke. Rod 32 is actuated between a top position and a
bottom position (power piston first and second position,
respectively) where its top portion rests just above pump barrel
seal 38 in a bottom position, at the completion of a downstroke;
and where its bottom portion rests just below pump barrel seal 38
in a top position, at the completion of an upstroke.
[0063] The combination of rod 32 and pump barrel seal 38 form a
fluid-tight seal; as such, downstroke reservoir 26 in the
embodiments shown in FIGS. 1A-1B and FIGS. 5A-5B, or upstroke
reservoir 22 in the embodiment shown in FIGS. 2A-2B, remains
completely sealed from first reservoir 40 and second reservoir 42
during both the upstroke and downstroke. In some embodiments,
connecting rod 32 and pump barrel seal 38 are fitted so that a
1/1000th inch gap is found on either side of rod 32. This fit is
thought to be most beneficial in that it allows rod 32 to freely
move between its top and bottom position while preventing
production oil from flowing between rod 32 and pump barrel seal 38.
Such a fluid tight seal is particularly beneficial in that it
separates the clean environment of power fluid 14 from the dirty
environment of the oil 62 cycled by system 10. As previously
discussed in the specification, this has not been possible with
known hydraulically-driven systems. More typical gasket materials,
with their erosion in such harsh conditions as are typically found
"down hole," are avoided.
[0064] In the alternative, a slightly "looser" fitting may be
selected, whereby power fluid 14, by design, is ejected in some
measure as a means for insuring lack of invasion of outside,
possibly corrosive, fluids into the power piston and cylinder
assembly. Such an alternative arrangement may be appropriate in
situations where particulates might score the tighter,
substantially fluid-tight, metal-to-metal seal. Also, some form of
corrosives-resistant "boot" through which connecting rod 32
extends, by which it is "wiped" as it cycles, may be provided to
protect seal 38 from particulate contamination.
[0065] Production piston 46 is connected to and rests just above
rod 32 in the embodiments shown in FIGS. 1A-1B and FIGS. 5A-5B, and
just below rod 32 in the embodiment shown in FIGS. 2A-2B, and is of
a generally solid cylindrical form. Production piston 46 is
actuated between a top position and a bottom position where
production piston 46 rests just above pump barrel seal 38 at the
completion of a downstroke in a bottom position; and piston 46
reaches just below one-way valve 52 at the completion of an
upstroke, in a top position in the embodiments shown in FIGS. 1A-1B
and FIGS. 5A-5B. In the embodiment shown in FIGS. 2A-2B, production
piston 46 is actuated between a top position and a bottom position,
where production piston 46 rests just below seal 38 at the
completion of an upstroke and just above valve 45 at the completion
of a downstroke. As previously mentioned in the specification, the
volume of both production piston 46 and power piston 30 may be
changed with respect to one another. This change in ratio between
production piston 46 and power piston 30 has particular
applicability in a low production energy context. Immediately above
pump barrel seal 38 is first reservoir 40, into which extends the
production piston end rod of connecting rod 32, which is in turn
connected to production piston 46 and the cylinder assembly portion
of the downhole pumping unit.
[0066] Immediately above pump barrel seal 38 in the embodiments
shown in FIGS. 1A-1B and FIGS. 5A-5B, and immediately above oil
inlet 41 in the embodiment shown in FIGS. 2A-2B, is first reservoir
40. Adjacent to first reservoir 40 is first inlet 41. In one
embodiment, first inlet 41 may have a one-way valve 45 that allows
oil 62 to flow into first reservoir 40 during an upstroke, but does
not allow backflow. During an upstroke, oil 62 (oil from a standard
type as known in the production zone of the subject well) is drawn
into system 10 through first inlet 41 where it travels through and
fills first reservoir 40. During a downstroke, oil 62 is pushed
from first reservoir 40 by production piston 46, and flows through
adjacent shaft 48, through one-way valve 49, and into upper
reservoir 53 (upper reservoir 53 is not shown in FIGS. 5A-5B).
Importantly, with this configuration, production of oil is
precisely doubled, yet there is no increase in energy consumption
in view of some systems that only pump oil during the upstroke.
[0067] Second reservoir 42 is positioned between production piston
46 and one-way valve 52. Adjacent to second reservoir 42 is second
inlet 43. In some embodiments, second inlet 43 may have a one-way
valve that allows oil 62 to flow into second reservoir 42 during a
downstroke, but does not allow backflow. During a downstroke, oil
62 is drawn into system 10 through second inlet 43 where it travels
through and fills second reservoir 42. During an upstroke, oil 62
is pushed from second reservoir 42 by production piston 46, and
flows through valve 52, through adjacent shaft 48 and into upper
reservoir 53. This pumping of production oil during the upstroke
compliments pumping of oil to the surface during the downstroke so
that oil travels to the surface in a continuous manner. Again, by
virtue of pumping oil 62 to the surface during both the upstroke
and downstroke, production of oil 62 is precisely doubled, yet
there is no increase in energy consumption in view of some systems
that only pump oil during the upstroke.
[0068] While some embodiments shown in FIGS. 1A-1B and FIGS. 5A-5B
show first reservoir 40 and second reservoir 42 as being positioned
above power piston 30, other useful embodiments are envisioned
where first reservoir 40 and second reservoir 42, and their
respective inlets, are positioned below power piston 30 such as the
embodiment shown in FIGS. 2A-2B. In such cases, the general
relationship between the components remains the same, and the
effectiveness of system 10 remains the same. In fact, system 10 is
still able to pump twice the amount of oil while expending the same
amount of energy.
[0069] In some embodiments, valve 52 is of a standard type as known
in the art. That is, a loosely seated bearing 51 rests upon a
grooved slot. Referring specifically to the embodiments shown in
FIGS. 1A-1B and FIGS. 2A-2B, during an upstroke, bearing 51 becomes
unseated and allows oil 62 to flow from second reservoir 42,
through valve 52, and into upper reservoir 53. Oil 62 easily flows
into reservoir 53 as bearing 51 becomes unseated and oil 62 is
pushed into reservoir 53. During a downstroke, bearing 51 remains
seated as fluid flows into reservoir 53 from adjacent shaft 48. As
system 10 completes a pumping cycle, oil 62 is continuously pushed
through reservoir 53 and adjoining reservoirs, separated by other
one-way valves, until oil 62 reaches the surface.
[0070] While alternatives may be employed, one-way valves depicted
in some embodiments are a standard ball valve type as are known in
the art. These essentially consist of a loosely-seated metal ball
or bearing resting upon a complimentarily contoured orifice. When
the ball is fully seated, little or no fluid may pass through the
orifice. When pressure is exerted from below the ball or bearing,
it is unseated, and fluid may pass through the orifice. However,
when pressure is exerted from above the ball, it is forced even
more into a sealed configuration, and little or no fluid may
pass.
[0071] Although the foregoing specific details describe certain
embodiments of this invention, persons reasonably skilled in the
art will recognize that various changes may be made in the details
of this invention without departing from the spirit and scope of
the invention as defined in the appended claims and considering the
doctrine of equivalents. Therefore, it should be understood that
this invention is not to be limited to the specific details shown
and described herein.
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