U.S. patent application number 12/925149 was filed with the patent office on 2012-04-19 for bailer stimulation production unit.
This patent application is currently assigned to Lift Tech LLC. Invention is credited to Delton W. Bishop, Charles Chester Irwin, JR., Harley McCorcle.
Application Number | 20120090851 12/925149 |
Document ID | / |
Family ID | 45933104 |
Filed Date | 2012-04-19 |
United States Patent
Application |
20120090851 |
Kind Code |
A1 |
Irwin, JR.; Charles Chester ;
et al. |
April 19, 2012 |
Bailer stimulation production unit
Abstract
An apparatus and process for gas, oil, and other fluid
production using bailer technology with stimulation to enhance
production. An enclosed apparatus and process for removing gas,
oil, and/or other fluids from a well while reducing environmental
impact. A novel divalve for simultaneously closing a conainer and
dumping liquids into it.
Inventors: |
Irwin, JR.; Charles Chester;
(Columbus, TX) ; McCorcle; Harley; (Gonzales,
TX) ; Bishop; Delton W.; (Luling, TX) |
Assignee: |
Lift Tech LLC
Luling
TX
|
Family ID: |
45933104 |
Appl. No.: |
12/925149 |
Filed: |
October 15, 2010 |
Current U.S.
Class: |
166/369 ;
166/105; 166/107; 166/321 |
Current CPC
Class: |
E21B 43/121
20130101 |
Class at
Publication: |
166/369 ;
166/105; 166/107; 166/321 |
International
Class: |
E21B 43/00 20060101
E21B043/00; E21B 34/00 20060101 E21B034/00; E21B 27/00 20060101
E21B027/00 |
Claims
1. An oil and gas recovery system comprising: a well casing
connecting a subterranean reservoir with a well head, a collection
housing docked to said well head with an open bottom surrounded by
a sealing flange, a bailer capable of entering through said open
bottom of said collection housing and being housed therein ("home")
with a canister, a means for loading liquids from said reservoir
into said canister, and a bivalve with a seal plate assembly that
includes a seal plate that seals against said sealing flange,
thereby closing said bottom of said collection housing and
simultaneously unseals from the bottom of said bailer, thereby
permitting liquids from said canister to unload into said
collection housing without exposing said liquids to the
environment, a winch and cable deployed over a pulley and attached
to said bailer for lowering said bailer from said collection
housing through said casing into said reservoir, retaining said
bailer as said canister fills with said reservoir liquids, and
lifting said bailer from said reservoir into said collection
housing, a stimulation means for stimulating production of fluids
from said reservoir, means for uninterrupted production of natural
gas from said reservoir without exposing said gas to the
environment, and a means for transferring said fluids from said
collection housing to storage facilities or pipelines.
2. The recovery system of claim 1 wherein said collection housing
and said bailer are cylindrical, the ID of said collection housing
is approximately ten to twenty percent less than the OD of said
bailer, the length of said bailer is sufficiently less than the
length of said collection housing that said bailer fits into said
collection housing in its "home" for unloading, and the top of said
housing has an opening for said cable.
3. The recovery system of claim 1 wherein said recovery system
includes a means for determining the depth of the surface of said
reservoir liquids, and a programmable logic controller for
controlling the fill, empty, and travel times for said bailer.
4. The recovery system of claim 3 wherein said means for
determining reservoir liquid depth is a scale temporarily attached
to said cable above said collection housing.
5. The recovery system of claim 1 wherein said stimulation means is
a plurality of disks suspended on a rod from said bailer.
6. The recovery system of claim 1 wherein said stimulation means
releases gases from reservoir fluids, creates additional turbulence
and/or to creates waves in said reservoir.
7. The recovery system of claim 6 wherein the shape of said disks
may be spherical, flat, or cup-shaped.
8. The recovery system of claim 1 wherein said internal means for
uninterrupted production of natural gas includes a spring-loaded
check valve centered over an opening in said seal plate.
9. The recovery system of claim 1 wherein said seal plate is flat
and circular.
10. The recovery system of claim 1 wherein said seal plate is
hemispherical.
11. The recovery system of claim 1 wherein said seal plate assembly
includes said seal plate, a retaining spring, and a retaining
plate.
12. The recovery system of claim 11 wherein said bivalve dumps
liquid from said canister into said collection housing when said
pulley compresses said retaining spring against said retaining
plate, thereby causing said seal plate to simultaneously seal to
said sealing flange and unseal from said bailer.
13. A process by which natural gas is produced and stored
comprising: the upward passage of natural gas from a subterranean
reservoir into a well casing, the continued upward passage of said
natural gas through an opening in a steal plate under a bailer
canister, a check valve under said bailer canister when the
pressure of said gas opens said valve, fluids in said bailer, and
vent holes in the top of said canister, into a collection housing,
and through outlet means to a storage facility or pipeline.
14. A process by which oil is produced and stored comprising:
lowering a bailer into a subterranean reservoir, stimulating fluids
in said reservoir, filling said bailer with oil from said
reservoir, lifting said bailer into its "home" position in a
collection housing, sealing a sealing plate to a sealing flange,
thereby closing the bottom of said housing, simultaneously
unsealing the bottom of said bailer, thereby unloading said oil
from said bailer into said collection housing, transferring said
oil from said collection housing to a storage facility or
pipeline.
15. An apparatus for increasing production of oil from a
subterranean reservoir comprising: a plurality of stimulators, a
means of immersing said stimulators into said reservoir near a
wellbore, thereby creating turbulence and waves in standing fluids
in said reservoir, and a means of retrieving said stimulators from
said reservoir.
16. The apparatus in claim 15 wherein said stimulators may be flat
disks, oval disks, spherical balls, or a combination thereof.
17. The apparatus in claim 15 wherein said stimulators are flat,
cupped-shaped disks that increase production by facilitating the
removal of solid particles from said standing fluids.
18. The apparatus in claim 15 wherein said stimulators facilitate
the removal of solid particles from said wellbore.
19. The apparatus in claim 15 wherein said stimulators increase
production by facilitating the flow of reservoir hydrocarbons to
said wellbore.
20. The apparatus in claim 15 wherein said stimulators are attached
to a rod attached to the bottom of a bailer in a bailer fluid
production system and said immersing and retrieval systems are said
bailer fluid production system.
21. A process for increasing production of oil from a subterranean
reservoir using a bailer recovery system comprising: lowering a
bailer with a plurality of stimulators attached underneath said
bailer into a well casing, immersing said stimulators into said
reservoir, creating turbulence and waves in standing fluids in said
reservoir, and retrieving said stimulators from said reservoir.
22. A production system for uninterrupted production of natural gas
from a subterranean reservoir comprising: a well casing connecting
said reservoir with a cylindrical collection housing, a cylindrical
bailer with an OD approximately eighty to ninety percent of the ID
of said collection housing, a check valve in the bottom of said
bailer providing gas communication between said reservoir and a
canister in said bailer when the pressure of said natural gas from
said reservoir is sufficient to open said valve, a plurality of
vent holes in the top of said canister providing gas communication
between said canister and a wellhead collection housing, and an
outlet means in said collection housing for transferring said
natural gas to a storage facility or pipeline.
23. A process for uninterrupted production of oil and natural gas
from an oil and gas well using a bailer recovery system comprising:
venting said natural gas around an empty bailer and through a check
valve and vent holes in said bailer while lowering said bailer
through a wellbore to the surface of a subterranean reservoir,
venting said natural gas through said wellbore while immersing said
bailer into said reservoir, venting said natural gas through said
wellbore as a canister in said bailer fills with said oil from said
reservoir, venting said natural gas around a full bailer while
retrieving said bailer from said reservoir into a collection
housing, venting said natural gas around a full bailer in said
collection housing, venting said natural gas around said bailer as
said oil empties from said canister into said collection housing,
venting said natural gas around said bailer and through said check
valve and said vent holes while said oil is transferred from said
collection housing to an oil storage facility or a pipeline,
transferring said natural gas and said oil from said collection
housing to storage facilities or pipelines, and repeating said
production steps for continued fluid production.
24. A bivalve for unloading liquid from a vessel comprising: a
collection housing with an opening through which said vessel may
enter and exit, a seal flange, and an outlet means for transferring
said liquids to a storage facility or pipeline, a means for moving
said vessel into and out of said collection housing, and a seal
plate that seals to said seal plate, thereby closing said
collection housing and unseals from the bottom of said vessel,
thereby opening said vessel and unloading said liquid from said
vessel into said collection housing when said vessel is "home"
inside said collection housing.
25. The bivalve of claim 24 wherein said vessel enters and exits
said collection housing through an opening in the bottom of said
collection housing which is sealed closed by said seal plate when
said vessel is "home" inside said collection housing.
26. The bivalve of claim 25 wherein said vessel and housing are
cylindrical, a winch and cable pull said vessel into said
collection housing, said seal plate seals against a sealing flange
in said bottom of said collection housing, said winch and cable
compresses said vessel against a spring as said vessel is pulled
into said collection housing, and said vessel separates from said
seal plate, thereby creating an opening for said liquid in said
vessel to flow into said collection housing, and thence to a
storage facility or pipeline via an outlet in said collection
housing.
27. The bivalve of claim 24 wherein said vessel is a bailer used to
produce oil from a well.
28. The bivalve of claim 27 used to release oil from said
bailer.
29. A process for emptying liquid from a vessel into a collection
housing comprising: moving said vessel up through an opening in the
base of said collection housing, sealing said opening, unsealing
said seal plate from the bottom of said vessel, thereby creating an
opening in the base of said vessel, unloading said liquid from said
vessel into said collection housing, transferring said liquid from
said housing into a storage facility or pipeline, sealing said seal
plate to the bottom of said vessel, unsealing said seal plate from
said opening, thereby reopening said collection housing, and moving
said vessel down through said housing opening.
30. The process of claim 29 wherein said opening in said collection
housing is sealed with a seal plate sealed to a sealing flange in
said bottom of said housing and said bottom of said vessel is
sealed with said seal plate sealed to said bottom of said
vessel.
31. The process of claim 29 wherein said seal plate is a flat plate
that seals under said opening in said bottom of said collection
housing.
32. The process of claim 29 wherein said seal plate is a
hemispherical seal that seals against the perimeter of said opening
in said bottom of said collection housing.
Description
FIELD OF INVENTION
[0001] The present invention relates to an inexpensive method for
recovering gas, water, crude oil, and/or other fluids using a
bailer lift system to transport fluids to the surface. The
invention further relates to recovery systems that may be
integrated in a single capture and unload component. The invention
further relates to production systems with reduced environmental
impact based on utilization of integrated components and processes
at the wellhead. The invention further relates to problems
associated with the aging process of the well and subterranean
formation. The invention further relates to the prevention of
decreased flow from well annulus due to corrosion, formation build
up, and other natural downhole processes. The invention further
relates to more cost-effective fluid extraction from marginal wells
as compared to purchase, maintenance, and operating costs of
conventional lift systems. The invention also relates to fluid
bearing subterranean formation stimulation to improve the flow of
formation fluid to the wellbore. The relation also relates to
simultaneous valving operations for dumping liquids.
BACKGROUND OF THE INVENTION
[0002] The novelty of BAILER STIMULATION PRODUCTION UNIT lies in
its cost-effective, simple, and environmentally safe operation, and
in its ability to enhance production from wells that respond to
stimulation. There is nothing new about bailer technology; it has
been employed by man since the first uses of containers to hold
water while moving it to higher elevations. There is nothing new
about using bailer technology to pump fluids from subterranean
reservoirs to wellheads; man has been doing that since long before
Samuel Woodworth wrote about "the moss-covered bucket which hung in
the well" in Scituate, Mass. two hundred years ago. Since then
numerous patents have been issued for bailer pumps for marginal oil
wells. Two competing goals for such systems is reduced costs versus
safety.
[0003] Some prior art bailer technology uses a pump or compressed
air to unload production fluids from a bailer (See, for example,
Strickland, U.S. Pat. No. 6,464,012 and Eggleston, U.S. Pat. No.
7,007,751). However, both processes are expensive, unreliable and
environmentally hazardous due to seals that must be maintained in
order for them to be functional. Moreover, air injected into a
hydrocarbon mixture is extremely dangerous. Conventional pumping
units used in low fluid wells have the risk of pump damage and
damage to the well annulus. Pulling machines, hot oilers, steamers,
and chemicals are extremely unfriendly to rods, tubing, downhole
pumps, etc. Therefore, the processes inside the well annulus pose a
potentially hazardous environmental impact because the corrosive
environment inside the well annulus attacks ferrous materials and
deposits them into the fluids and formations. Moreover, this
corrosive environment requires expensive and labor intensive
maintenance of conventional pump wells including rod and tubing
maintenance, costs to fish parts and repair and clean them,
downtime for repairs, and removal of paraffin and iron sulfide
disposals.
[0004] Most prior art bailer pump systems use gravity to unload
fluids from the bailer. An important advantage of gravity unloading
is that it is cheap--nature does the work. A disadvantage is that
it may expose the environment to toxic fluids and/or risk spillage
and waste. For example, Klaeger, U.S. Pat. No. 4,086,035 exposes
recovered oil to the open atmosphere. On the other hand, Alexander,
U.S. Pat. No. 4,368,909 temporarily seals the wellhead closed to
prevent the escape of fluids such as natural gas during unloading.
However, sealing the wellhead during unloading may result in
dangerous pressure buildup which must be released before the bailer
commences the next retrieval cycle. Recent prior art is driven by
the need for less and less expensive extraction costs and dwindling
reservoir levels and may achieve cheaper production at the expense
of environmental safety. For example, Grant, U.S. Pat. No.
7,481,271 discloses an extraction system that produces oil from
stripper wells cheaply, but the extraction container is emptied by
tilting it over a funnel connected to a storage tank.
[0005] The present invention uses gravity flow unloading in a novel
way. It not only produces oil from marginal wells inexpensively, it
does so without releasing toxic fluids to the atmosphere during
unloading, and without sealing the wellhead and interrupting
production.
[0006] Feedback means for controlling the timing of bailer
extraction systems has come a long way. The primary variable in the
timing of bailer extraction systems is the distance between the
wellhead and the liquid surface of the subterranean reservoir.
Sensing devices commonly used today can determine the depth of the
top of the liquid surface, and even the depth of the oil or
oil/water interface in the reservoir. Senghaas, U.S. Pat. No.
4,516,911 teaches the use of manually adjustable timers and floats
to prevent overflow. Rice, U.S. Pat. No. 6,460,622 & U.S. Pat.
No. 6,615,924 introduced a programmable logic controller (PLC) with
sensors for monitoring operational parameters which may change and
then be used to re-calibrate timing. The present invention likewise
uses a standard PLC served by information from the well.
[0007] Prior art bailer pump systems provide for exhausting natural
gas and recovering it at the wellhead (Rice, U.S. Pat. No.
6,460,622) and using conventional separating means (Rice, U.S. Pat.
No. 6,615,924).
[0008] Finally, bailer recovery systems provide inherent well
stimulation each time the bailer plunges into a reservoir. The
present invention utilizes additional novel stimulation means in
wells where such means enhance production. For example, in
reservoirs containing viscous fluids, or a suspension which
effectively increases its viscosity, agitating the fluid enhances
diffusion and may thereby improve production.
[0009] Thus, the present invention provides an inexpensive means
for recovering natural gas without interrupting production, a novel
valve for unloading bailers and other vessels, and a novel means
for treating downhole fluids to increase production, all with
substantially reduced costs, risks of spillage and environmental
damage.
SUMMARY OF THE INVENTION
[0010] As with all prior art bailer pumps, the present invention
utilizes a bailer pumping apparatus comprising a collection housing
connected to a wellhead, a reversible motor driving a winch which
reels in and unreels a cable carried over a pulley connected to a
bailer. Bailers have means for loading and unloading fluids and a
canister for holding them.
[0011] Modern bailing pumps are controlled by a PLC. Typically,
when the bailer is "home" in the collection housing, the winch is
filled with cable, and the loaded canister unloads liquid. When the
canister is empty, the PLC actuates the motor, and cable unwinds
from the winch. When the bailer is immersed in the subterranean
reservoir, the PLC stops the motor, and fluid flows into the
canister. When the canister is full, the PLC reverses the motor
direction and raises the bailer back up into the collection
housing. When the bailer is back "home" in the collection housing,
a sensor signals the PLC to stop the motor, and the steps described
above are repeated as needed for production.
[0012] There are a number of ways that PLC's may be programmed to
time these events. For example, the load and unload times may be
programmed manually or from feedback based on bailer weight, which
may be monitored by a scale placed under the pulley. The decent and
ascent times may be calculated by the PCL from the winch velocity
and the depth of the reservoir, which may also be determined from
feedback from the bailer based on its weight.
[0013] The collection housing in a preferred embodiment of the
present invention is a vertical stand pipe attached to the top of a
well (wellhead). The housing is of sufficient length and inside
diameter (ID) to contain a cylindrical bailer. The housing has an
opening for the cable at the top with a wiper seal and cleaning
means, and a sealing flange or surface for sealing the housing
closed before liquids are unloaded into it from the bailer. A
natural gas outlet and an outlet for produced liquids are connected
to gas and liquid storage facilities. The simplicity of the
collection housing greatly reduces its fabrication cost compared to
existing bailer collection means.
[0014] The bailer is normally a streamlined cylinder designed to
slide smoothly into subterranean reservoir fluids. The outside
diameter (OD) of the bailer and the ID of the well casing should be
such that there is sufficient space for natural gas to vent around
the bailer as it is lowered and raised through the casing, and the
bailer may vary in length to accommodate the desired production
rate as long as it does not exceed the length of its collection
housing. The top of the bailer has a means for attaching the cable,
orifices for filling the canister from the top and/or to allow it
to vent air or other gases while filling from the bottom, and a
means for accommodating fishing tools should the cable break. A
check valve for filling the canister while the bailer is submerged
in the reservoir may be in the bottom of the bailer or attached
under it. The bailer used in the present invention also has a means
for attaching a stimulator for use in wells where stimulation
improves production and a novel double valve for (a) closing the
housing used to collect liquid, and (b) for unloading liquid from a
vessel inside said collection housing (BIVALVE) that includes a
seal plate with at least two sealing surfaces, a retainer spring
assembly and spring holder. The seal plate, which may be flat,
oval, or ball-shaped as needed, has a first surface that is
slightly larger than the ID of the collection housing, and a second
surface that, when sealed to the canister or other vessel, prevents
liquid contained therein from flowing out. This assembly provides a
novel valve for unloading liquids from vessels.
[0015] In some embodiments of the present invention, the check
valve may be set to vent natural gas from the well through the
canister, seal plate and check valve.
[0016] The stimulation means in the present invention provides a
novel means for increasing production from wells that benefit from
its agitating action. The means, which acts as a plunger when
immersed into and withdrawn from a fluid, is designed to create
turbulence as it is lowered into and retrieved from a subterranean
reservoir. Flat or cup-shaped stimulators create a pronounced wave
as well as turbulence. The wave can move solid particles that have
migrated through the formation into the bailer. Such wave motion is
also expected to cause lower molecular weight hydrocarbons to be
released as natural gas. Such gases stimulate diffusion when they
bubble through a viscous fluid. Ball and flat disks also create
turbulence. This turbulence and enhanced diffusion can help stir up
and suspend solid particles in the wellbore so that they can be
removed in the bailer.
[0017] The stimulators used in the present invention come in
numerous forms and configurations. The means employed is what works
best for a specific well. Some wells might not benefit from
stimulation. Production from other wells may be stimulated by means
consisting of a plurality of circular plates and/or balls on a rod
suspended from the bottom of the bailer. The plates may be flat
and/or oval disks, and/or cup- and/or ball-shaped disks may be
used. The rod length, number of disks and/or balls and their
spacing will vary depending on reservoir fluid levels, fluid
viscosity, debris buildup, and a number of other well
characteristics.
[0018] In the preferred embodiment of the present invention
employed for wells benefiting from stimulation, when a
bailer/stimulator assembly is lowered into and raised from a
reservoir, the well fluid experiences pulse and agitation effects
from the plunging action of the stimulators. This pulse or
agitation promotes movement in the formation fluid near the
wellbore (stimulation). When the bailer is immersed, its canister
fills with reservoir fluid through the inlet check valve and/or
through orifices in the top of the bailer. When the cable begins to
lift the full bailer from the reservoir, the check valve closes. As
the full canister is raised from the reservoir by the winch, the
stimulators again creates pulses and agitation effects in the well
fluid.
[0019] The full bailer is pulled inside when it reaches the
collection housing, and the invention's novel BIVALVE seals the
collection housing closed and empties the canister. When the
canister is empty, the winch reverses direction and lowers the
bailer for another collection cycle.
[0020] The sequence described above repeats itself as needed,
limited solely by bailer travel and fill/drain times, which may be
controlled and/or modified by the PLC as described previously.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 . . . General representation of the bailer recovery
system (BRS).
[0022] FIG. 2a . . . Embodiment of the Well Stimulation Means (WSM)
using flat disks.
[0023] FIG. 2b . . . Embodiment of the WSM using round disks.
[0024] FIG. 2c . . . Embodiment of the WSM using cupped-shaped
disks.
[0025] FIG. 2d . . . Embodiment of the WSM using a combination of
stimulator shapes.
[0026] FIG. 3a . . . Embodiment of bailer with check valve above
seal plate.
[0027] FIG. 3b . . . Embodiment of bailer with check valve under
seal plate.
[0028] FIG. 3c . . . Illustration of ball check valve.
[0029] FIG. 4a . . . The empty fluid collection housing (CCH).
[0030] FIG. 4b . . . Illustration of bailer moving into or from
CCH.
[0031] FIG. 5a . . . "Closed" BIVALVE using a flat seal plate.
[0032] FIG. 5b . . . "Open" BIVALVE using a flat seal plate.
[0033] FIG. 6a . . . "Closed BIVALVE using a hemispheric seal
plate.
[0034] FIG. 6b . . . "Open BIVALVE using a hemispheric seal
plate.
[0035] FIG. 7a . . . "Closed" BIVALVE in a bailer recovery system
(BRS).
[0036] FIG. 7b . . . "Open" BIVALVE in a BRS.
[0037] FIG. 8 . . . Another Preferred embodiment of the
BIVALVE.
[0038] FIG. 9a . . . BIVALVE in "transition state."
[0039] FIG. 9b . . . "Closed" BIVALVE unloading liquid from
canister.
[0040] FIG. 10a . . . Illustration of bailer when it is nearly
home.
[0041] FIG. 10b . . . Bailer at "home" unloading liquid.
DETAILED DESCRIPTION OF THE INVENTION
[0042] The invention disclosed herein is a bailer fluid production
system and process. The invention utilizes a novel means for
stimulating liquid hydrocarbon production, and a novel double valve
for unloading it to storage facilities without exposing the
environment to hydrocarbons during their uninterrupted
production.
[0043] FIG. 1 illustrates the invention generally as bailer
recovery system (BRS) 10, which includes vertical, cylindrical
collection housing (CCH) 12, and bailer 14. Sensor 16 signals the
system's PLC (not shown) that bailer 14 is "home" inside housing
12. Cable 18 connects winch 20 to bailer 14 via pulley 22 through
the top of housing 12 to connection means 24. Check valve 26 is
used to load reservoir fluids into bailer 14 when bailer 14 is
immersed in such fluids, the invention's novel BIVALVE 28 is used
to close a collection housing (e.g. CCH 12) and unload liquid from
a vessel therein (e.g. bailer 14), and weighing means 30, which may
be a scale or a load cell, may be employed to monitor the weight of
bailer 14. The entire system is installed atop wellhead 32, and the
invention's novel well stimulating means (WSM) 34 may be attached
under valve 26 and wellhead connection 36.
[0044] FIG. 2 illustrates the invention's novel well stimulation
means. WSM 34 comprises a plurality of stimulators 38 on rod 40,
which may be removably attached externally to bailer 14 under it.
WSM 34 is designed to create turbulence in standing fluids in well
reservoirs. Depending on the type of stimulation needed for
enhanced production, stimulators 38 may be flat and/or oval disks,
and/or ball-shaped means (FIGS. 2a and 2b) may be used. The length
of rod 40 and the number of stimulators 38 and their spacing will
vary depending on reservoir fluid levels, fluid viscosity and a
number of other well parameters. Stimulators 38 create turbulence
which agitates and suspends solid particles in the wellbore,
thereby facilitating their removal. Flat or cupped-shaped disks
(FIG. 2c) also generate a pronounced wave. Such wave motion
likewise stirs up solid particles that migrated through the
formation and causes them to move into the wellbore where they can
be removed. Such wave motion also causes "light ends" of
hydrocarbons in the reservoir to be released as natural gas, which
promotes flow of heavier hydrocarbons to the wellbore. In many
applications, a combination of stimulator shapes FIG. 2d) may be
preferred to enhance production.
[0045] FIG. 3 illustrates how bailer 14 may vent natural gas and
load reservoir fluid when it is downhole. Canister 42 is the
portion of bailer 14 that holds reservoir liquids as bailer 14 is
lifted from a subterranean reservoir. Before bailer 14 is immersed
in reservoir fluid, check valve 26, which may be above seal plate
44 (FIG. 3a) or under it (FIG. 3b), may be open or closed,
depending on environmental factors in the wellbore. For example,
when the pressure of natural gas is sufficiently high, valve 26 is
open, thereby permitting gas to vent through valve 26 and an
opening in seal plate 44, thence through canister 42 and orifices
46.
[0046] When winch 20 in FIG. 1 has unwound sufficient cable that
empty canister 42 is immersed in a subterranean reservoir,
stimulating means 34 creates pulse and agitation effects which
promote movement in the formation fluid in the reservoir. When the
fluid pressure exceeds the pressure required to open valve 26,
valve 26 opens, thereby allowing fluid to flow into canister 42.
Liquid may also load into canister 42 through orifices 46. When
canister 42 is full, winch 20 in FIG. 1 begins to lift bailer 14
from the reservoir, and valve 26 closes. Scale 30 in FIG. 1
measures the weight of bailer 14 as it leaves the reservoir and the
length of cable extending therein, thereby permitting a
determination of the reservoir fluid level downhole.
[0047] FIG. 3a illustrates an embodiment of the invention wherein
check valve 26 is housed inside bailer 14 (above plate 44); FIG. 3b
illustrates an embodiment wherein valve 26 is under bailer 14
(below plate 44). FIG. 3c illustrates the details of check valve 26
when a ball check valve is used. However, depending on the fluid
characteristics of the well where it is used, valve 26 may be a
ball, flapper or plunger check valve.
[0048] FIG. 4 illustrates the collection housing in FIG. 1 when it
is empty (FIG. 4a), and when bailer 14 is moving into or from
housing 12 (FIG. 4b). CCH 12 includes sensor 16 for determining
when bailer 14 is "home," wellhead connection 36 for connecting
housing 12 to a wellhead, attachment means 48 for attaching a cable
cleaning means for cleaning cable 18 before it passes through
opening 50 and for closing opening 50, gas outlet means 52 for
transferring natural gas to a gas storage facility (not shown), at
least one fluid outlet means 54 for transferring produced fluids to
a fluid storage facility (not shown), and sealing surface 56 for
sealing seal plate 44. Basically, the ID and length of housing 12
is sufficient to house the bailer, except for plate 44 (described
below) and stimulation means 34 (if attached). In FIG. 4b, bailer
14 is being lowered from or raised into housing 12 by cable 20.
[0049] The present invention produces natural gas without
interrupting production by venting gas through valve 26 and plate
44, canister 42 and orifices 46 and/or around the bailer to outlet
means 52 and thence to a gas storage facility or pipeline (not
shown). This function of the invention also prevents pressure from
building up to dangerous levels, and/or being released into the
atmosphere.
[0050] FIGS. 5 and 6 illustrate preferred embodiments of the
invention's novel BIVALVE being used to unload fluid from a
cylindrical vessel (e.g. canister 42). BIVALVE 28 includes, spring
60, rod, 62, retaining plate 64, valve holder 66, top surface 68 of
valve holder 66 and seal plate 44, which is the bottom of holder
66. When BIVALVE 28 is closed, plate 44 seals to the bottom of
holder 66, thereby closing vessel 42. As vessel 42 moves toward its
"home" position in housing 12, plate 44 engages sealing surface 56,
thereby sealing housing 12 closed and preventing upward movement of
retaining plate 64. "Overpull" of vessel 42 compresses spring 60
against retaining plate 64, thereby unsealing plate 44 and opening
the bottom of vessel 42. Additional overpull of vessel 42 is
limited by compression of spring 60 against retaining plate 64.
After vessel 42 empties and begins to move back down, the
compression of spring 60 is released, plate 44 is unsealed from
sealing surface 56 and seals holder 66 closed.
[0051] In the embodiment in FIG. 5, flat-type seal plate 44 seals
to sealing surface 56 under the base of housing 12. In FIG. 5a,
vessel 42 is entering housing 12, and plate 44 is sealed to vessel
42 and below sealing surface 56 (BIVALVE 28 is "closed"). In FIG.
5b, plate 44 seals to surface 56 as it begins to separate from the
bottom of vessel 42 (BIVALVE 28 is in its "transition state"). In
FIG. 5c, plate 44 is unsealed from holder 66, thereby permitting
vessel 42 to unload liquid, but plate 44 seals the bottom of
housing 12 closed, thereby preventing said liquid from escaping
(BIVALVE 28 is "open").
[0052] In the embodiment in FIG. 6, hemispherical type seal plate
44 plugs into sealing surface 56, which is the tapered rim of a
circular opening in the base of housing 12. The narrowest diameter
of said opening must be greater than the OD of vessel 42 but less
than the diameter of seal plate 44. In FIG. 6a, plate 44 is
unsealed from the bottom of holder 66, thereby permitting vessel 42
to unload liquid, but plate 44 seals the bottom of housing 12
closed, thereby preventing said liquid from escaping (BIVALVE 28 is
"open"). In FIG. 6b, plate 44 seals the bottom of vessel 42 closed,
and the bottom of housing 12 is no longer sealed shut, thereby
permitting vessel 42 to exit housing 12 (BIVALVE 28 is
"closed").
[0053] FIG. 7 illustrates the use of BIVALVE 28 in a bailer
recovery system. In FIG. 7a, bailer 14 is full of oil and has
entered housing 12, but seal plate 44 has not yet reached sealing
surface 56 and is still sealed to the bottom of holder 66 (BIVALVE
28 is "closed"). In FIG. 7b, sensor 16 signals the system's PLC
(not shown) that bailer 14 is "home," and BIVALVE 28 is unloading
fluid from canister 42 into housing 12 (BIVALVE 28 is "open"). Said
fluid is transferred to storage facilities (not shown) through
fluid outlet 54 in housing 12.
[0054] FIG. 8 illustrates a different embodiment of BIVALVE 28. In
FIG. 8, BIVALVE 28, which includes spring 60, rod, 62, retaining
plate 64, valve holder 66, top surface 68 of valve holder 66 and
seal plate 44 is in its "transition state" where seal plate 44 has
reached sealing surface 56, but is still sealed to the bottom of
holder 66 (BIVALVE 28 is "in transition").
[0055] FIG. 9 illustrates how BIVALVE 28 moves from its transition
state (FIG. 9a) to its open position (FIG. 9b). In FIG. 9, BIVALVE
28, which includes spring 60, rod, 62, retaining plate 64, valve
holder 66, top surface 68 of valve holder 66 and seal plate 44, is
housed in the bottom of bailer 14. In FIG. 9a, bailer 14 is inside
collection housing 12, seal plate 44 has reached sealing surface 56
of collection housing 12, but plate 44 is still sealed to bottom 70
of bailer canister 42 under holder 66 (BIVALVE 28 is in
"transition"). In FIG. 9b, spring 60 is compressed against
retaining plate 64 as wench 20 in FIG. 1 overpulls bailer canister
42 approximately two and a half inches into housing 12. The
compression of spring 60 seals plate 44 to sealing surface 56,
thereby sealing collection housing 12 closed, as the overpull of
bailer 14 separates bottom 70 of canister 42 from plate 44, thereby
permitting gravity to unload liquid from bailer 14 into housing
12.
[0056] FIG. 10 illustrates bailer 14 moving into its "home"
position in collection housing 12. In the embodiment in FIG. 10,
BIVALVE 28 is the version of the bivalve shown in FIG. 9. In FIG.
10a, bailer 14 is nearly "home" as in FIG. 9a. In FIG. 10b, the top
of bailer 14, which is overpulled approximately two and a half
inches into housing 12, is detected by sensor 16. Sensor 16 signals
the system's PLC (not shown) that bailer 14 is "home." As shown in
FIG. 9b, plate 44 has separated from the bottom of canister 42,
thereby unloading liquid from bailer canister 42 into collection
housing 12.
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