U.S. patent application number 14/025324 was filed with the patent office on 2014-01-16 for hydraulic actuated pump system.
This patent application is currently assigned to CANASONICS INC.. The applicant listed for this patent is CANASONICS INC.. Invention is credited to William Emil GROVES.
Application Number | 20140014328 14/025324 |
Document ID | / |
Family ID | 40522286 |
Filed Date | 2014-01-16 |
United States Patent
Application |
20140014328 |
Kind Code |
A1 |
GROVES; William Emil |
January 16, 2014 |
HYDRAULIC ACTUATED PUMP SYSTEM
Abstract
The invention is directed to a hydraulic actuated pump system
which lifts production fluids and re-circulating hydraulic fluid
from a petroleum well. Additives may be added to the hydraulic
fluid to apply direct chemical treatment to the production
formation. A sonic stimulator may be included to stimulate and
produce the same liquids from the horizontal section of the
well.
Inventors: |
GROVES; William Emil;
(Calgary, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CANASONICS INC. |
CALGARY |
|
CA |
|
|
Assignee: |
CANASONICS INC.
CALGARY
CA
|
Family ID: |
40522286 |
Appl. No.: |
14/025324 |
Filed: |
September 12, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13287265 |
Nov 2, 2011 |
8534353 |
|
|
14025324 |
|
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|
12246255 |
Oct 6, 2008 |
8069914 |
|
|
13287265 |
|
|
|
|
60978007 |
Oct 5, 2007 |
|
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Current U.S.
Class: |
166/249 |
Current CPC
Class: |
E21B 43/003 20130101;
E21B 43/124 20130101; E21B 28/00 20130101 |
Class at
Publication: |
166/249 |
International
Class: |
E21B 43/00 20060101
E21B043/00; E21B 28/00 20060101 E21B028/00 |
Claims
1. A method of enhanced oil recovery from a formation, comprising
the steps of: (a) installing a sonic stimulator into an injection
wellbore, or a horizontal section of a wellbore, on the end of
coiled tubing; (b) activating the sonic stimulator with a liquid
hydraulic power fluid to produce acoustic waves having a frequency
of about 80 Hz to about 250 Hz, and inject hydraulic power fluid
into the formation; (c) using the liquid hydraulic power fluid to
sweep oil towards one or more proximate production wells, or from
the horizontal section of a wellbore towards a vertical section of
the wellbore.
2. The method of claim 1, wherein the liquid hydraulic power fluid
comprises water, produced water, water-based fluids, water-oil
emulsions, inorganic salt solutions, biodegradable plant-based
hydraulic fluids, or synthetic and naturally occurring organic
materials.
3. The method of claim 2, wherein the liquid hydraulic power fluid
is supplemented with one or more additives comprising oils,
butanol, esters, silicones, alkylated aromatic hydrocarbons,
polyalphaolefins, or corrosion inhibitors.
4. The method of claim 3, wherein the one or more additives
comprises a brine-based, heavy oil solution for creating a light
oil-in-water emulsion within the production fluids.
5. The method of claim 2 wherein the liquid hydraulic fluid or the
supplemented hydraulic fluid is heated to a temperature ranging
from about 30.degree. to 101.degree. C.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application of U.S. patent
application Ser. No. 13/287,265 filed on Nov. 2, 2011, which is a
divisional application of U.S. patent application Ser. No.
12/246,255 filed on Oct. 6, 2008, now U.S. Pat. No. 8,069,914
issued on Jun. 12, 2011, which application claimed the priority of
U.S. Provisional Patent Application 60/978,007 filed Oct. 5, 2007,
entitled "Hydraulic Actuated Pump System, the entire contents of
which are incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a hydraulic actuated pump
system and sonic stimulation tools for downhole applications.
BACKGROUND OF THE INVENTION
[0003] Within a petroleum producing well, the production string
forms the primary conduit through which production fluids (liquids,
gases, or any fluid produced from a wellbore) are produced to the
surface. The production string is typically assembled with
production tubing and completion components in a configuration that
suits the wellbore conditions and the production method. Oil wells
typically vary from a few hundred to several thousand feet in
depth, and there is often insufficient formation pressure to cause
the flow of production fluids through the production string to the
surface.
[0004] Several prior art systems involving different pumping and
extraction devices have been developed for the surface transfer of
production fluids from a well. Downhole hydraulic pumps installed
deep within the well are commonly used. A surface hydraulic pump
pressurizes power oil which drives the downhole pump. When a single
production string is used, the power oil is pumped down the tubing
and a mixture of the formation crude oil and power oil are produced
through the casing-tubing annulus. If two production strings are
used, the power oil is pumped through one of the pipes, and the
mixture of formation crude oil and power oil are produced in the
other, parallel pipe.
[0005] Prior art artificial lift systems include for example, the
progressive cavity pump and plunger lift, both of which are
installed on jointed or continuous rods; electric submersible
pumps; gear pumps installable on tubing and powered by downhole
electric or hydraulic motors; and the venturi lift which is run on
coiled tubing but is not a total production system. However, such
systems tend to be complex and/or of substantial size and weight,
requiring significant structural support elements at the wellhead
which increase the expense of the overall system.
SUMMARY OF THE INVENTION
[0006] The present invention is directed to a hydraulic actuated
pump system. In one aspect of the invention, the invention
comprises a pump system for lifting production fluids to the
surface or circulating service fluids in a wellbore, comprising:
[0007] (a) a cylindrical outer tubular member and an cylindrical
inner tubular member in a concentric orientation therewith,
defining an annular bore therebetween; [0008] (b) a production
packer sealing the annular bore in a downhole location proximate a
production zone; [0009] (c) means for pumping hydraulic fluid from
the surface into the annular bore; [0010] (d) wherein the inner
tubular member defines an inner bore extending therethrough to
allow upward passage of a mixture of hydraulic fluid and production
fluids from the wellbore, wherein the inner bore is open to the
production zone; [0011] (e) a plurality of jet members spaced
intermittently along the wellbore, wherein each jet member defines
at least one jet nozzle providing fluid communication from the
annular bore to the inner bore; [0012] (f) wherein the at least one
jet nozzle is adapted and oriented to provide a high velocity
hydraulic fluid stream into the inner bore thereby providing a lift
force to fluid in the inner bore.
[0013] In one embodiment, the jet members comprise a plurality of
nozzles having diameters sized to project fluid streams. In one
embodiment, the downhole assembly may include one or more of a
production packer, a reciprocating bit, a sonic stimulator, a sonic
stimulator with a reciprocating bit, a drill motor with a drill
bit, or a drill motor with a casing reaming assembly. In one
embodiment, the downhole assembly comprises a production packer
having threaded hold-down slips, threaded set-down slips, and
packer elements positioned between the hold-down slips and set-down
slips to seal against an inner wall of the production casing.
[0014] In one embodiment, the downhole assembly comprises a sonic
stimulator for emitting pressure waves into the formation
production zone. In one embodiment, the sonic stimulator comprises
an elongate body defining a bore extending therethrough, a
plurality of tubular jet members, and a hydraulic coupling which
generates pulsed pressure waves. In one embodiment, at least one of
the jet members includes a nozzle.
[0015] In one embodiment, the sonic stimulator comprises an
elongate body defining a bore extending therethrough to house a
valve retainer, a valve, a plurality of jet members, a resonance
assembly, a rod retainer, a piston assembly moveable between a
first position and a second position, and biasing means for biasing
the piston towards the first position. In one embodiment, the jet
members comprise one or more nozzles. In one embodiment, the jet
members are rotatable. In one embodiment, the biasing means
comprises a coil spring.
[0016] In one embodiment, the hydraulic fluid comprises water,
produced water, water-based fluids, water-oil emulsions, inorganic
salt solutions, biodegradable plant-based hydraulic fluids, or
synthetic or naturally occurring organic materials. In one
embodiment, the hydraulic fluid is supplemented with one or more
additives selected from oils, butanol, esters, silicones, alkylated
aromatic hydrocarbons, polyalphaolefins, or corrosion inhibitors.
In one embodiment, the one or more additives comprise a
brine-based, heavy oil chemistry for creating a light oil-in-water
emulsion within the production fluids. In one embodiment, the
supplemented hydraulic fluid is sonified. In one embodiment, the
hydraulic fluid or the supplemented hydraulic fluid is heated to a
temperature ranging from about 30.degree. to about 101.degree.
C.
[0017] In another aspect, the invention may comprise a sonic
stimulator for downhole use in a petroleum well, comprising: [0018]
(a) an inlet for receiving a hydraulic fluid under pressure; [0019]
(b) a wave generator for generating an acoustic wave as the
hydraulic fluid passes through the wave generator; and [0020] (c) a
jet member for exhausting the hydraulic fluid from the sonic
stimulator.
[0021] In another aspect, the invention may comprise a method of
enhanced oil recovery from a formation, comprising the steps of:
[0022] (a) installing a sonic stimulator into a wellbore; [0023]
(b) activating the sonic stimulator with a hydraulic power fluid to
produce acoustic waves and inject the hydraulic power fluid into
the formation; [0024] (c) using the hydraulic power fluid to sweep
heavy oil towards a production well. The hydraulic power fluid may
comprise one or more additives to assist in mobilization or
emulsification of the heavy oil. The addition of the additives may
be tapered so as to place the additives in specific portions of the
wellbore. The additives may comprise an alkaline component and a
surfactant component.
[0025] In one embodiment, the wellbore is a production well, and
comprises a vertical portion, and a horizontal portion, and the
additives are added so as to place the additives in a toe portion
of the horizontal portion. Alternatively, the wellbore may comprise
an injection well, and is proximate one or more production
wells.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The invention will now be described by way of an exemplary
embodiment with reference to the accompanying simplified,
diagrammatic, not-to-scale drawings.
[0027] FIG. 1 is a schematic cross-sectional view of a pump system
of one embodiment of the present invention.
[0028] FIG. 1a is a diagrammatic representation of a tubular jet
member of a pump system of FIG. 1.
[0029] FIG. 2 is a diagrammatic representation of a pump system of
one embodiment of the present invention.
[0030] FIG. 3 is a diagrammatic representation of a pump system of
FIG. 2 in connection with surface components.
[0031] FIG. 4 is a diagrammatic representation of a pump system of
one embodiment of the present invention, including a sonic
stimulator.
[0032] FIG. 5 is a diagrammatic representation of a pump system of
FIG. 4 in connection with surface components.
[0033] FIG. 6 is a diagrammatic representation of a sonic
stimulator of one embodiment of the present invention.
[0034] FIG. 7 is a diagrammatic representation of a sonic
stimulator of FIG. 6, showing the pathway of hydraulic fluid.
[0035] FIG. 8 is a diagrammatic representation of an exploded view
of a hydraulic drive of the sonic stimulator of FIG. 6.
[0036] FIG. 9 is a diagrammatic representation of a sonic
stimulator of one embodiment of the present invention.
[0037] FIG. 10 is a diagrammatic representation of a hydraulic
drive unit of the sonic stimulator of FIG. 9.
DETAILED DESCRIPTION OF THE INVENTION
[0038] The present invention provides for a hydraulic actuated pump
system. When describing the present invention, all terms not
defined herein have their common art-recognized meanings. To the
extent that the following description is of a specific embodiment
or a particular use of the invention, it is intended to be
illustrative only, and not limiting of the claimed invention. The
following description is intended to cover all alternatives,
modifications and equivalents that are included in the spirit and
scope of the invention, as defined in the appended claims.
[0039] "Horizontal" means a plane that is substantially parallel to
the plane of the horizon. "Vertical" means a plane that is
perpendicular to the horizontal plane. One skilled in the art will
recognize that wellbores may not be strictly vertical or
horizontal, and may be slanted or curved in various
configurations.
[0040] The hydraulic actuated pump system (1) lifts production
fluids and re-circulating hydraulic fluid from the wellbore. The
hydraulic fluid is pressurized to drive the system. Additives may
be added to the hydraulic fluid to apply direct chemical treatment
to the production formation. A sonic stimulator may be included in
conjunction with the pump system to stimulate and produce the same
liquids from the well.
[0041] In one embodiment, the system may be applied to a well
having a substantially vertical portion, and a substantially
horizontal portion. Horizontal directional drilling to create such
a wellbore is well known in the art.
[0042] The pump system (1) is shown schematically in FIG. 1 in a
vertical well and comprises an outer tubular member (10), an inner
tubular member (12), a plurality of jet members (14), a plurality
of crossover members (16), and a downhole assembly (18). The well
is cased with conventional well casing (20). As the annulus (36)
between the pump system (1) and the production casing (20) is not
necessarily used to transport fluids within the well, the pump
system may be sized to fit within the casing to a close
tolerance.
[0043] The outer tubular member (10) is generally cylindrical and
houses the inner tubular member (12) in a concentric orientation
therewith, forming an annular bore (22) to allow passage of
hydraulic fluid (indicated by arrow "a") through an inlet (24) from
the surface. As used herein and in the claims, the term
"concentric" refers to components sharing a common center and thus
a uniform annular dimension. However, two tubular members where one
has a smaller diameter and is placed within the other may be
considered concentric, even if they do not share the exact
geometric centre, and even if they are not circular in
cross-section.
[0044] The inner tubular member (12) is preferably generally
cylindrical and defines an inner bore (26) which is open to the
production zone of the formation. In one embodiment, the outer and
inner tubular members (10, 12) are concentric coil or jointed
tubular members. A coiled tubular member comprises a continuous
length of tubing, while a jointed tubular member comprises lengths
of tubing joined together by suitable attachment means. Both coiled
and jointed tubing are well known in the art and further
description is not needed.
[0045] A production packer (18) is provided as part of the downhole
assembly to isolate the annular space between the inner and outer
tubular members from the inner bore (26) of the inner tubular
members.
[0046] A plurality of jet members (14) are provided along the
length of the inner tubular members (12), spaced intermittently
along the length of the wellbore. In one embodiment, the jet
members (14) form part of the inner tubular string, and comprise at
least one nozzle (30) having diameters sized to project streams of
pressurized fluid (FIG. 1a). In a preferred embodiment, a plurality
of nozzles are arrayed circumferentially about the diameter of the
jet member (14) and are aimed upwards. In one embodiment, the
nozzles (30) are convergent, narrowing from a wide diameter to a
smaller diameter to accelerate fluid flow. In operation, power
fluid is pumped into the annular space at high pressure. Because
the annular space is closed by the production packer, the power
fluid flows through the jet member nozzles (30) upwards into the
inner bore. The jet members (14) create a high velocity flow
upwards into the inner bore, creating a venturi effect and sucking
production fluid upwards in the inner bore.
[0047] The jet members (14) may be centralized within the annulus
by portions in contact with the outer tubular members, as shown
schematically in FIG. 1. In this case, sufficient openings in the
annular bore to allow power fluid to reach lower jet members must
of course be provided. Alternatively, the jet members may form part
of inner tubular string, and not contact the outer tubular members,
as shown in FIG. 2.
[0048] Crossover members (16) are included to connect components
with different thread types or sizes. In one embodiment, a
crossover member (16a) is sized to connect and cap the outer and
inner tubular members (10, 12) at the surface, and defines an
aperture (34) through which the outlet means (28) extends to the
surface. In one embodiment, a crossover member (16b) connects the
outer and inner tubular members (10, 12) with the downhole assembly
(18).
[0049] The downhole assembly may comprise one or more of a variety
of components including, for example, a production packer (18), a
reciprocating bit, a sonic stimulator, a sonic stimulator with a
reciprocating bit, a drill motor with a drill bit, a drill motor
with a casing reaming assembly, or other suitable components known
to those skilled in the art. In one embodiment, the downhole
assembly comprises a production packer (18) for anchoring the
tubular members (10, 12) and isolating the annulus (36) from the
production formation. The production packer (18) may comprise
threaded hold-down slips (18a), threaded set-down slips (18b), and
packer elements (18c) (for example, rubber O-rings) positioned
between the hold-down slips (18a) and set-down slips (18b) to seal
against the inner wall of the production casing (20) to isolate the
well's annulus (36) from the production formation. Tail pipe or
lower completion elements (18d) are mounted below the set-down
slips (18b).
[0050] In one embodiment shown in FIG. 2, the casing (20) has a
plurality of perforations (38) at its end (40) to enable fluid
communication with the formation production zone, namely the target
reservoir rock containing production fluids including, for example,
water, oil, condensates, or natural gas. FIG. 3 shows this
embodiment of the invention in connection with surface
components.
[0051] In operation, hydraulic power fluid (as indicated by arrows
"a") is placed into a recirculation tank (42) at the surface. The
operation of a recirculation tank (42) is commonly known to those
skilled in the art and will not be discussed in detail. Briefly,
the recirculation tank (42) for preparing power fluid is generally
configured with a tank, a pump to circulate the fluid, and a
manifold system to control recirculation and delivery of the fluid
to the hydraulic pump (44).
[0052] Suitable hydraulic power fluid includes, for example, water,
produced water, water-based fluids, water-oil emulsions, inorganic
salt solutions, biodegradable plant-based hydraulic fluids,
synthetic and naturally occurring organic materials to create a
hydraulic oil or fluid of similar properties. Base stock may be any
of, for example, castor oil, glycol, esters, mineral oil,
organophosphate ester, polyalphaolefin, propylene glycol or
silicone. Commercially available hydraulic fluids include, for
example, Durad.RTM., Fyrquel.RTM., Houghton-Safe.RTM.,
Hydraunycoil.RTM., Lubritherm.RTM. Enviro-Safe, Pydraul.RTM.,
Quintolubric.RTM., Reofos.RTM., Reolube.RTM., and Skydrol.RTM.. The
hydraulic fluid for the pump system is selected based upon various
properties including, for example, stable viscosity, chemical and
physical stability, system compatibility, flash point, low
volatility, low coefficient of expansion, minimal rust formation
and fire resistance. In one embodiment, the hydraulic fluid is
water. In one embodiment, the hydraulic fluid is produced water
which is re-circulated through the pump system (1).
[0053] Hydraulic fluid may be supplemented with one or more
additives having desirable properties including, for example, the
remediative capacity to carry solids, reduce oil viscosity, create
and extend worm-holes in the wellbore area, solvate dead heavy oil,
and establish communication with additional connate gas which
assists fluid inflow. The additives may include oils, butanol,
esters, silicones, alkylated aromatic hydrocarbons,
polyalphaolefins, corrosion inhibitors, surfactants, dispersants,
solvents, and other suitable chemical compounds. In one embodiment,
the additive is a brine-based, heavy oil solution which creates a
light oil-in-water emulsion within the production fluid. In one
embodiment, the hydraulic fluid or supplemented hydraulic fluid may
be heated to a temperature ranging from about 30.degree. to about
101.degree. C.
[0054] The hydraulic fluid, which may be heated, is then drawn
through a hydraulic pump (44) and injected into the lower flow tee
(46) of the wellhead (48) and into the outer tubular string (22).
Injection of hydraulic fluid may be either batch or continuous
injection. The hydraulic fluid injection rate relates to the volume
of fluid injected in a well during hydraulic pumping. It will be
understood by those skilled in the art that injection testing is
initially conducted to establish the rate and pressure at which
fluid can be pumped into the treatment target without damaging or
fracturing the production formation. In one embodiment, the
hydraulic pump (44) injects at rates ranging from about 60 to 400
L/min. at an operating pressure ranging from about 8 to 24 MPa. The
heated hydraulic fluid is injected into the annulus (22) until the
inner tubular members (12) and the formation have been fully
saturated, thereby "priming" the pump system. Continued pumping
lifts the mixture of hydraulic fluid and production fluids through
the inner tubular member (12) via the venturi effect described
above. The venturi effect increases the kinetic energy of the
fluid, providing sufficient lift to reach the surface (as indicated
by the arrow "b").
[0055] At the surface, a separator (50) separates the production
fluids from the hydraulic fluid, directing the production fluid
into one or more outflow lines (52) for further processing, and the
hydraulic fluid through a filter (54) to the recirculation tank
(42) for re-heating and re-entry into the pump system (1). The
operation of a separator (50) is commonly known to those skilled in
the art. Briefly, a separator (50) comprises a cylindrical or
spherical vessel used to separate oil, gas and water from the total
fluid stream produced by the well. Separators can be either
horizontal or vertical. Separators can be classified into two-phase
and three-phase separators, with the two-phase type dealing with
oil and gas, and the three-phase type handling oil, water and gas.
Gravity segregation is the main force that accomplishes the
separation based on fluid density. Additionally, inside the vessel,
the degree of separation between gas and liquid will depend on the
separator operating pressure, the residence time of the fluid
mixture and the type of flow of the fluid. Production separation
begins with the well flowstreams entering the vessel horizontally
and hitting a series of perpendicular plates. This causes liquids
to drop to the bottom of the vessel while gas rises to the top.
Gravity separates the liquids into oil and water. The gas, oil and
water phases are metered individually as they exit the unit through
separate outflow lines.
[0056] In one embodiment, the pump system (1) is installed within
the well as a permanent production system. In one embodiment, the
pump system (1) is portable, serving as a temporary work over,
treating and clean out system, with outer and inner coils (not
shown) substituting as the outer and inner tubular members (10, 12)
respectively. In one embodiment, the outer coil has a diameter of 2
inches, while the inner coil has a diameter of 1.75 inches. The
crossover member (16b) may be modified to receive a portion of the
hydraulic fluid which is injected to power the pump system (1)
within the inner coil, and divert the hydraulic fluid to run a
combination of service tools off the end of the outer coil. The
outer coil may be wound to a spool to be conveyed via a coiled
tubing unit to a desired service interval. The coiled tubing unit
has an integrated hydraulic pump, coil injector, and a production
tank to handle the circulated solids and liquids, all preferably
mounted on one vehicle. Tools which may be run off the end of the
outer coil include, for example, a bit for scraping the casing of
the wellbore by reciprocating the coil; a sonic stimulator; a drill
motor with a drill bit; or other suitable tools known to those
skilled in the art.
[0057] In one embodiment, the pump system (1) includes a sonic
stimulator which emits acoustic waves to vibrate liquids and solids
within the production formation. As used herein and in the claims,
the term "acoustic waves" means pressure waves propagating through
the production formation. In one embodiment, and without
restriction to a theory, we believe the acoustic waves cause
vibration at the molecular level of liquids and solids in the
producing zone, which assists in the mobilization and production of
fluids. Molecular vibration may result in one or more of the
following beneficial effects: repairs and removes naturally
occurring or man-made formation damage; suspends wellbore damage in
suspension fluid; removes scale, filter cake, wax, asphaltenes,
bitumen or other materials; increases reservoir connectivity,
injectivity and production; enhances stimulation fluid; stimulates
selectively; and decreases the viscosity of heavy oil to facilitate
its mobilization.
[0058] The sonic stimulator can be incorporated with, for example,
vertical, horizontal, liner, gas, oil, injection, and production
wells. The sonic stimulator may be installed following completion
of the well, and preferably after injection of the heated power
liquid into the annulus (36). In one embodiment, the sonic
stimulator is placed in the horizontal section of a well.
[0059] Once the pump system (1) has begun to lift the mixture of
hydraulic fluid and production fluids to the surface, the sonic
stimulator is injected using coiled tubing to the desired depth in
the well's horizontal section. Use of a smaller diameter coiled
tubing results in higher pressure, while a larger diameter coiled
tubing results in lower pressure. Of course, pressure within the
coiled tubing is dependent also on flowrate. The sonic stimulator
may be injected into the wellhead (48) at the surface by a suitable
crossover member or wellhead device (not shown). The coiled tubing
is diverted to the discharge side of the hydraulic pump (44) which
is adjusted to ensure that the injection rates are suitable for
both the pump system (1) and the sonic stimulator.
[0060] The hydraulic fluid injected into the coiled tubing actuates
the sonic stimulator's internal hydraulic drive, which creates
acoustic waves. The hydraulic fluid exiting tubular jet members of
the sonic stimulator permeates the formation, thereby creating a
fluid environment which enables acoustic waves to propagate through
the formation production zone. The penetration of the acoustic
waves depends on numerous factors, including the amplitude and
frequency of the waves, and the formation characteristics. In one
embodiment, the acoustic waves may propagate up to about 12 feet
outward within the formation. The acoustic waves mobilize fluids
towards the horizontal section of the wellbore. Either or both the
acoustic waves and the jet members of the sonic stimulator generate
a negative pressure face at the perforations (38) of the horizontal
section or the well to further mobilize the production fluids into
the wellbore. The jet members then push the production fluids
towards the vertical section of the well. The heated hydraulic
fluid ensures that the production fluids, particularly the heavy
oil, remain mobilized and less viscous as they are lifted to the
surface by the pump system (1). At the surface, the separator (50)
separates the production fluids from the hydraulic fluid, directing
the production fluid into one or more outflow lines (52) for
further processing, and the hydraulic fluid through a filter (54)
to the recirculation tank (42) for re-heating and re-entry into the
pump system (1).
[0061] An appropriate sonic stimulator for inclusion with the pump
system (1) is selected based upon the quality and volume of
hydraulic fluid required for the well. In one embodiment, the sonic
stimulator (56) is included in the pump system (1) in which the
quality of the hydraulic fluid is exceptional and the hydraulic
fluid injection rate exceeds about 60 L/min. In one embodiment, the
sonic stimulator (82) is included in the pump system (1) in which
the quality of the hydraulic fluid is poor and the hydraulic fluid
injection rate is less than about 60 L/min. The flow rate required
to create lift in the inner bore is typically between about 30-300
L/min, at a pressure of about 7-14 MPa.
[0062] In general terms, the sonic stimulator (56) may be any
device which produces acoustic waves from a stream of pressurized
hydraulic fluid. Acoustic waves are pressure waves which propagate
through the hydraulic fluid, and through the formation.
[0063] In one embodiment shown in FIGS. 4 to 7, the sonic
stimulator (56) comprises an elongate body (58) defining a bore
(60) extending therethrough, a plurality of tubular jet members
(62), and a hydraulic coupling (64). A crossover (66) connects the
jet members (62) within the elongate body (58). In one embodiment,
additional jet members (68) are included to provide extra lift for
heavy solid production. In one embodiment, jet members (62) are
positioned at the end and the middle sections of the body (58).
[0064] As indicated in FIG. 7, the hydraulic fluid enters the sonic
stimulator (56) via the coiled tubing (70) attached to the
hydraulic pump (44) at the surface. The hydraulic fluid passes
through the bore (60) of the sonic stimulator (56) and into the
hydraulic coupling (64). The jet members (62) expel the hydraulic
fluid from both ends of the sonic stimulator (56). In one
embodiment, at least one of the jet members (62) includes a nozzle
(72) which produces a high velocity stream of fluid. This fluid
stream may act as a cleaner during installation of the sonic
stimulator (56), and contributes to the negative pressure face at
the perforations (38). In one embodiment, at least one jet member
(62) is machined to project at an angle as shown in FIG. 6, such
that the expelled hydraulic fluid creates a vortex which provides
lift to produced solids. The hydraulic fluid exits the jet members
(62) from the middle of the sonic stimulator (56) by operation of
the hydraulic coupling (64).
[0065] Hydraulic couplings for high pressure hydraulic circuits are
well known in the art. In one embodiment shown in FIG. 8, the
hydraulic coupling (64) is formed of two connectable cylindrical
halves, with one half comprising elements (72, 74) and the other
half comprising elements (76, 78, 80). Elements (72, 74) are
generally cylindrical and have opposed side apertures (72a, 74a).
In one embodiment, apertures (74a) have a larger diameter than
apertures (72a). During manufacture, element (72) is heat-shrunk
over element (74) with apertures (72a, 74a) in axial alignment.
[0066] Element (76) is generally cylindrical defining a bore
extending therethrough to allow insertion of element (78). Element
(76) include a plurality of apertures (76a, 76b) in a face plate.
In one embodiment, a plurality of smaller diameter apertures (76a)
are arranged on the circumference of the face plate of element (76)
to encircle a larger diameter, central aperture (76b). Element (78)
is generally cylindrical defining a bore extending therethrough and
having two opposed end faces (78a, the other shown in phantom in
FIG. 8). Each face (78a) has a plurality of apertures (78b, 78c).
In one embodiment, a plurality of smaller diameter apertures (78b)
are arranged on the circumference of the face (78a) to encircle a
larger diameter, central aperture (78c). Opposed side apertures
(78d) (shown in phantom in FIG. 8) are present in the mid-section
of element (78). In one embodiment, element (78) is notched at its
ends to load into elements (76, 80). Element (80) is generally
cylindrical defining a bore extending therethrough to an end face
(80a). The end face (80a) has a plurality of apertures (80b, 80c).
In one embodiment, a plurality of smaller diameter apertures (80b)
are arranged on the circumference of the end face (80a) to encircle
a larger diameter, central aperture (80c).
[0067] In one embodiment, when elements (76, 78, 80) are engaged,
the face plate apertures of elements (76) and (78) are offset to
avoid alignment. Further, the number of apertures of elements (76,
78) differs. In one embodiment, seven apertures (76a) in element
(76) feed six apertures (78b) in element (78). Elements (76, 78,
80) insert into elements (72, 74) of which threads (72b, 74b)
couple together the two halves to form the hydraulic coupling
(64).
[0068] During operation, the hydraulic fluid enters the hydraulic
coupling (64) through apertures (76a, 76b). Since apertures of
element (78) are offset to apertures of element (76), element (78)
rotates as the hydraulic fluid passes through element (78) into
element (80). Hydraulic fluid which enters the central aperture
(76b) passes into the central aperture (78c) of rotating element
(78). Hydraulic fluid exits from apertures (78d) and from element
(80) to feed the jet member (60). In one embodiment, the jet member
(60) includes a nozzle (72).
[0069] Elements (72, 74) serve as a resonance chamber which forms
pressure pulses as the hydraulic fluid passes through the coupling.
The frequency of the pulses depends upon the number of apertures
which transfer the hydraulic fluid from apertures (78b) to
apertures (78d). During each rotation of element (78), a pulse
emits as streaming hydraulic fluid hits (i.e., pulses) the
resonance chamber formed by elements (72, 74). The wave frequency
is determined by the number of pulses per second which can be used
to calculate the wavelength being exerted on the production
formation. The pressure at which the hydraulic fluid is injected by
the hydraulic pump (44) determines the amplitude of the waves and
the magnitude of the wave action upon the production formation. The
pressure pulses emitted by the hydraulic coupling (64) of the sonic
stimulator (56) propagate along the body (58) to create a similar
effect (i.e., pulsation) at the jet members (62) at the ends of the
sonic stimulator (56). The result is a high cleaning efficiency
across greater areas of the wellbore. In one embodiment, the sonic
stimulator (56) can stimulate or clean in the range of about 18 to
48 inches in radius, or up to about 8 feet in diameter.
[0070] In one embodiment, the sonic stimulator (56) creates pulses
with a frequency of about 80 to 250 Hz, with about 30 hp of pulse
pressure at the sonic stimulator (56). In one embodiment, the
hydraulic coupling (64) requires a pressure range of approximately
5 to 7 MPa back pressure in the sonic stimulator (56) to operate at
this rate. In one embodiment, fluid rates range from about 30 to
350 L/min at about 7 to 24 MPa, Preferably, the flow rate is about
100-200 L/min at about 7-14 MPa. It is understood by those skilled
in the art that the higher the fluid rate, the higher the pressure,
and thus, the greater the pulse pressure (measured in hp) generated
at the sonic stimulator (56). Low frequency, high amplitude
applications may be designed, which may be achieved with fluid
rates less than about 30 L/min, and as low as about 10 L/Min.
[0071] In one embodiment shown in FIGS. 9 to 10, the sonic
stimulator (82) comprises an elongate housing (84) defining a bore
(86) extending therethrough to house a valve assembly comprising a
valve retainer (88) and a valve (90), a plurality of jet members
(92), a resonance section (94), a piston assembly (96, 98, 100)
which is moveable between a first position and a second position,
and biasing means for biasing the piston (100) towards the first
position. The piston (100) fits within reasonably close tolerance
to the inside diameter of the housing (84) and divides the sonic
stimulator (82) into a proximal section and a distal section. The
piston need not fit fluid-tight within the bore, therefore piston
rings or seals are not necessary. When fluid is pumped into the
proximal section, it passes through the valve assembly, through the
resonance assembly and against the piston (100). In one embodiment,
the jet members (92) are rotatable on the resonance section (94).
In one embodiment, one jet member is an end jet member (93)
disposed at the distal end of the sonic stimulator. In one
embodiment, the biasing means (102) is a coil spring.
[0072] The hydraulic fluid enters the sonic stimulator (82) via the
coiled tubing (70) attached to the hydraulic pump (44) at the
surface. The fluid passes into the bore (86) of the sonic
stimulator (82) through the apertures (88a) of the valve retainer
(88) to open the valve (90). The valve (90) allows the passage of
the hydraulic fluid to the jet members (92). The jet members (92)
are ring shaped and are rotatably mounted on the resonance section
(94). Resonance apertures (94a) in the resonance section (94) are
each sized having a diameter larger than that of apertures (92b).
The fluid passes through large-diameter apertures (94a) and exits
small-diameter circumferential apertures (92b) of the jet members
(92), when the apertures are aligned. The circumferential apertures
(92b) are machined at a tangential angle so that fluid exiting the
jet members (92) causes them to rotate. When the apertures (92b,
94a) of the jet members (92) and resonance assembly (94) align, a
resonance chamber forms and a pressure pulse is emitted. The number
of apertures of the jet members (92) and the speed at which the jet
members (92) rotate determine the frequency of the pressure pulses.
The flowrate at which the hydraulic fluid is injected determines
the power.
[0073] In one embodiment, the hydraulic fluid passes through the
apertures (96a) of the rod retainer (96) to act on the piston (100)
against the biasing means (102). The force of the piston (100)
compresses the biasing means (102 and expels fluid from the distal
portion through the end jet member (93) and nozzles (104). Once the
biasing means (102) is maximally compressed, pressure builds up
within the resonance chamber (94), causing closure of the valve
(90). The hydraulic fluid continues to exit the jet members (92)
until the biasing means (102) overcomes the pressure exerted by the
fluid, forcing the fluid backwards. The piston (100) increases the
velocity of the hydraulic fluid, which creates a frequency
variation by increasing the speed at which the jet members (92)
rotate. As the biasing means (102) retracts, it pulls hydraulic
fluid from outside the sonic stimulator through the end jet member
(93) and nozzles (104). In one embodiment, the end jet member (93)
comprises three nozzles (104). The hydraulic fluid is expelled on
the next cycle of the piston (100), creating a pulse from the one
or more nozzles (104). Pulsation at both ends of the sonic
stimulator (82) increases the efficiency of the sonic stimulator
(82) on the production formation. Once the biasing means (102) has
fully retracted, the pressure of further injected fluid into the
sonic stimulator bore (86) opens the valve (90) and the cycle
repeats.
[0074] The valve (90) may comprise a one-way valve such as a ball
valve, or a check valve.
[0075] Aspects of the present invention may be combined with
alternative enhanced oil recovery techniques. For example,
alkali-surfactant (AS) flooding is an established enhanced oil
recovery technique used in conventional oil reservoirs. These
chemicals carried in the injection brine lower the oil/water
interfacial tension mobilizing the flow of some of the trapped
oil.
[0076] Alkali-surfactant flooding with polymers has been more
recently employed to improve EOR flooding of moderately heavy oil.
Without polymer flooding or SAGD efforts only 20% or less of the
OIP (Oil in Place) may be recovered by primary production
techniques due to solution gas drive. With pressure draw down and
loss of the gas drive the reservoir energy becomes too depleted for
further cold pumping to be economically viable.
[0077] It is known that certain types of AS injection, without the
addition of polymers, can be used for enhanced non-thermal heavy
oil recovery. AS injection, under shear conditions, can reduce the
interfacial tension between oil and water to values that allow for
oil-in-water or water-in-oil emulsions to form providing enough
viscosity and self diversion to sweep additional HOIP (Heavy Oil in
Place).
[0078] The combination of a sonic stimulator tool (56 or 82) of the
present invention and AS flooding may provide efficient recovery of
HOIP. The hydraulic power fluid may include additives to perform AS
flooding. The sonic stimulator passes the fluid into the formation
under shear conditions with uniform propagation, which may
stabilize in situ emulsions. Thus, the mobility ratio between water
and heavy oil may be reduced and ultimately improve heavy oil sweep
efficiencies. These sonic tools can be placed and landed on coiled
tubing either in the horizontal section of heavy oil wells or in an
injection well strategically placed in a water flood pattern. In a
horizontal well installation the tapered injection of AS brine
under sonic conditions may generate an energized chemical plume
which will sweep `toe to heel` heavy oil. A tapered injection of AS
brine is one where the concentration of additives is varied
according to the position of the sonic tool in the wellbore. One
skilled in the art will understand the the "toe" of a horizontal
portion of a well comprises the distal end of the well, away from
the vertical section. In an injection well, the same energized
chemical plume will sweep emulsified heavy oil outwards to a set of
surrounding production wells.
[0079] The acoustic waves, which applied at a suitable frequency
and amplitude, generated by the sonic stimulators may provide deep
uniform penetration of the power fluid, which may have a designed
chemistry, and may enhance or generate heavy oil water emulsions
for flooding purposes.
[0080] The present invention is advantageous over designs of the
prior art. The hydraulic actuated pump system (1) lifts production
fluids, solids (i.e., sand, shale, clay) and re-circulating
hydraulic fluid from the vertical section of a wellbore. The
hydraulic fluid and production fluids conveniently drive the
system. The hydraulic fluid may comprise water or re-circulated,
produced water, thus minimizing cleaning and expense. Further, the
hydraulic fluid may be supplemented with additives to apply direct
chemical treatment of the production formation, replacing the
commonly used drip systems which lack control over chemical
placement. Low bottom hole pressure wells may be worked over
without requiring nitrogen. Further, the pump system eliminates the
requirement for complex, downhole moving parts, and avoids heat
issues with thermal floods.
[0081] Systems which include moving parts downhole in thermal
floods damage quickly and wear out due to high operating
temperatures. In the present invention, this is less likely to
occur as there are fewer downhole moving parts, temperature does
not affect the pump parts, temperature will affect the fluid if it
reaches boiling under pressure, but if this occurs it will have
even greater velocity to carry fluid from the annulus.
[0082] The pump system including a sonic stimulator thus permits
injection, cleaning, stimulation and production without requiring
well shut down for any of these activities. The pump system may be
installed permanently within the well, or modified to be portable,
serving as a temporary work over, treating and clean out
system.
[0083] Where power requirements for the pump system (1) or any
component thereof is described, one skilled in the art will realize
that any suitable power source may be used, including, without
limitation, electrical systems, rechargeable and non-rechargeable
batteries, self-contained power units, or other appropriate
sources.
[0084] In one embodiment, the production of fluids may be enhanced
by the use of chemical additives in the power fluid for the jet
pump system, or the power fluid to drive the sonic stimulator, or
both.
[0085] As will be apparent to those skilled in the art, various
modifications, adaptations and variations of the foregoing specific
disclosure can be made without departing from the scope of the
invention claimed herein.
* * * * *