U.S. patent application number 11/155057 was filed with the patent office on 2005-10-20 for apparatus, method and system for single well solution-mining.
Invention is credited to Brown, Neil, Nesselrode, Karl.
Application Number | 20050231022 11/155057 |
Document ID | / |
Family ID | 25452248 |
Filed Date | 2005-10-20 |
United States Patent
Application |
20050231022 |
Kind Code |
A1 |
Brown, Neil ; et
al. |
October 20, 2005 |
Apparatus, method and system for single well solution-mining
Abstract
A method, system and apparatus is presented for solution-mining
of subterranean materials such as trona, nahcolite, thermonatrite,
pirssonite, natron, dawsonite, wegscheiderite, gaylussite,
shortite, halite, and other salts, minerals, and so forth. The
method comprises injecting a fluid into an elbow well, the fluid
forming a subterranean mixture with the subterranean material in a
single cavity, and collecting the subterranean mixture from the
elbow well. The system comprises an injector for injecting a fluid
into an elbow well, the fluid forming a subterranean mixture with
the subterranean material in a single cavity, and a collector for
collecting the subterranean mixture from the elbow well. The
apparatus comprises a production casing, wherein the production
casing has a production casing inner diameter of sufficient size to
allow for production of a subterranean mixture of the fluid and the
subterranean material between an outer surface of the injection
tube and an inner surface of the production casing.
Inventors: |
Brown, Neil; (The Woodlands,
TX) ; Nesselrode, Karl; (The Woodlands, TX) |
Correspondence
Address: |
ARNOLD & FERRERA, L.L.P.
2401 FOUNTAIN VIEW DRIVE
SUITE 630
HOUSTON
TX
77057
US
|
Family ID: |
25452248 |
Appl. No.: |
11/155057 |
Filed: |
June 17, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11155057 |
Jun 17, 2005 |
|
|
|
09925788 |
Aug 9, 2001 |
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Current U.S.
Class: |
299/5 |
Current CPC
Class: |
E21B 43/28 20130101 |
Class at
Publication: |
299/005 |
International
Class: |
E21B 001/00 |
Claims
What is claimed is:
1. A method for solution-mining a subterranean material in an elbow
well having a single cavity, said method comprising: injecting a
fluid into said elbow well through only a single opening disposed
at a terminal end of an injection tube, said fluid forming a
subterranean mixture with said subterranean material in said single
cavity; and collecting said subterranean mixture from said elbow
well.
2. The method of claim 1, wherein said subterranean material
comprises trona.
3. The method of claim 1, further comprising making said elbow
well.
4. The method of claim 3, wherein said making said elbow well
comprises drilling an elbow well into a bed comprising said
subterranean material.
5. The method of claim 1, wherein said method further comprises
casing said elbow well.
6. The method of claim 1, wherein said injecting a fluid further
comprises injecting said fluid into an injection tube located in
said elbow well.
7. The method of claim 1, wherein said single cavity comprises said
subterranean material mixture after said injecting said fluid.
8. The method of claim 1, wherein said subterranean mixture
comprises a subterranean solution.
9. The method of claim 1, wherein said fluid comprises water.
10. The method of claim 1, wherein said fluid comprises a caustic
mixture.
11. The method of claim 1, wherein said method further comprises
heating said fluid.
12. The method of claim 1, wherein said collecting said
subterranean mixture further comprises collecting said subterranean
mixture through a production tube located in said elbow well.
13. The method of claim 1, wherein said collecting said
subterranean mixture comprises pumping said subterranean
mixture.
14. The method of claim 13, wherein said pumping said subterranean
mixture comprises lifting said subterranean mixture through a
production tube.
15. The method of claim 14, wherein said method further comprises
delivering said subterranean mixture to a collection location.
16. The method of claim 15, wherein said collection location
comprises the earth's surface.
17. The method of claim 13, wherein said method further comprises
placing a pump in said elbow well.
18. The method of claim 1, wherein said method occurs at ambient
well pressure.
19. The method of claim 1, wherein said method further comprises
processing said subterranean mixture after said collecting said
subterranean mixture.
20. A system for solution-mining a subterranean material in an
elbow well having a single cavity, said system comprising: an
injection means for injecting a fluid into said elbow well through
only a single opening disposed at a terminal end of said injection
means, said fluid forming a subterranean mixture with said
subterranean material in said single cavity; and a collection means
for collecting said subterranean mixture from said elbow well.
21. The system of claim 20, wherein said subterranean material
comprises trona.
22. The system of claim 20, wherein said system further comprises a
means for casing said elbow well.
23. The system of claim 20, wherein said means for injecting said
fluid further comprises an injection tube located in said elbow
well.
24. The system of claim 20, wherein said subterranean mixture
comprises a subterranean solution.
25. The system of claim 20, wherein said fluid comprises water.
26. The system of claim 20, wherein said fluid comprises a caustic
mixture.
27. The system of claim 20, wherein said means for collecting said
subterranean mixture comprises a means for pumping said
subterranean mixture.
28. The system of claim 27, wherein said system further comprises a
means for placing a pump in said elbow well.
29. The system of claim 27, wherein said system further comprises a
means for delivering said subterranean mixture to a collection
location.
30. The system of claim 29, wherein said collection location
comprises the earth's surface.
31. The system of claim 20, wherein said system operates at ambient
well pressure.
32. An apparatus for solution-mining a subterranean material in an
elbow well having a single cavity, said apparatus comprising: an
injection tube, wherein said injection tube has an inner diameter
of sufficient size to allow for injection of a fluid through only a
single opening disposed at a terminal end of said injection tube;
and a production casing, wherein said production casing has a
production casing inner diameter of sufficient size to allow for
production of a subterranean mixture of said fluid and said
subterranean material between an outer surface of said injection
tube and an inner surface of said production casing.
33. The apparatus of claim 32, further comprising a production tube
for collecting said subterranean mixture.
34. The apparatus of claim 33, further comprising a pump connected
to said production tube.
Description
RELATED APPLICATION DATA
[0001] The instant application is a continuation of Ser. No.
09/925,788, filed Mar. 31, 2004, now abandoned, which is a request
for continued examination of Ser. No. 09/925,788, filed Aug. 9,
2001, now abandoned, to which the instant application claims
priority.
BACKGROUND OF THE INVENTION
[0002] This invention relates to solution-mining of subterranean
materials. The following discusses the disclosed solution-mining
invention as applied to trona, but it is understood that this
solution-mining invention applies to all subterranean
materials.
[0003] The subterranean material trona, also known as natural soda
ash, is a crystalline form of sodium carbonate and sodium
bicarbonate, known as sodium sesquicarbonate, having the formula
Na.sub.2CO.sub.3.NaHCO.sub.3.2- H.sub.2O. Worldwide, deposits of
natural trona are rare, but the world's largest known deposit is
located in the Green River Basin of southwestern Wyoming. Smaller
deposits of trona are found near Memphis, Egypt and the Lower Nile
Valley, widely throughout the soda lakes of Africa, Armenia, and
Iran, and in the alkali deserts of Mongolia and Tibet. From natural
trona, the primary end product is soda ash. In fact, Wyoming
produces 90% of the processed soda ash in the United States and 30%
of the world's supply. Other end-products from trona include sodium
bicarbonate, caustic soda, sodium sulfite, sodium cyanide and
sodium phosphate. Improved and cheaper processes for mining trona
from natural deposits are desired.
[0004] Mining is an age-old approach for removing subterranean
materials, e.g., trona, nahcolite, dawsonite, wegscheiderite,
thermonatrite, pirssonite, natron, gaylussite, shortite, halite,
and other salts, minerals, and so forth. Many deposits of
subterranean materials, however, do not permit commercially viable
extraction, whether through underground mechanical mining or
solution-mining. For example, not even 10% of known trona deposits
permit commercially viable underground mechanical mining, and trona
solution-mining has not been economical.
[0005] Underground mechanical mining requires deep shafts to remove
the subterranean material, and ever-deeper shafts are used as more
material is extracted. In addition, mechanical mining is
people-intensive. This creates a dangerous operating
environment.
[0006] After lifting the material to the surface, the material is
calcined to expel volatile components, such as carbon dioxide.
Calcination is an energy-intensive processing step that affects the
economics of mechanical mining. After calcination, the calcined
material is recrystallized in aqueous solution, collected, dried
and ready for further processing or shipping.
[0007] Solution-mining is a touted alternative to mechanical
mining, but solution-mining has not proven as economical as
desired. Solution-mining of subterranean materials, in particular,
trona, is possible using hot water or alkaline solutions. For
example, U.S. Pat. No. 2,388,009 (Pike) discloses the use of a hot
water or hot carbonate solution as the mining fluid. See also U.S.
Pat. No. 2,625,384 (Pike et al.); U.S. Pat. No. 2,847,202 (Pullen);
U.S. Pat. No. 2,979,315 (Bays); U.S. Pat. No. 3,018,095
(Redlinger); U.S. Pat. No. 3,050,290 (Caldwell et al.); U.S. Pat.
No. 3,086,760 (Bays); U.S. Pat. No. 3,184,287 (Gancy); U.S. Pat.
No. 3,405,974 (Handley et al.); U.S. Pat. No. 3,952,073 (Kube);
U.S. Pat. No. 4,283,372 (Frint et al.); U.S. Pat. No. 4,288,419
(Copenhafer et al.); and U.S. Pat. No. 4,344,650 (Pinsky et al.),
all of which are incorporated herein by reference. These
disclosures, and other documented solution-mining processes, reveal
use of two or more of the following economic drains on commercial
viability: high temperatures, high pressure calcination, hydraulic
fracturing ("fracturing"), and two wells, wherein one well is for
injection and one well is for production, see e.g., U.S. Pat. No.
4,815,790, Rosar, et al.; U.S. Pat. No. 4,344,650, Pinsky, et al.;
U.S. Pat. No. 4,252,781, Fujita, et al.; U.S. Pat. No. 4,022,868,
Poncha, et al.; U.S. Pat. No. 4,021,526, Gancy et al.; and U.S.
Pat. No. 4,021,525, Poncha, all of which are incorporated herein by
reference. Fracturing rarely fractures only the material to be
removed, so injecting hot water or alkaline solution dissolves
other materials, including salts, and contaminates the subterranean
material product collected from the production well. Collection of
contaminated subterranean materials is yet another economic drain
to commercial viable solution-mining processes.
[0008] In addition to solution-mining of trona, various U.S.
patents disclose solution-mining of nahcolite (predominantly
NaHCO.sub.3). For example, U.S. Pat. No. 3,779,602 (Beard et al.)
and U.S. Pat. No. 3,792,902 (Towell et al.), and U.S. Pat. No.
3,952,073 (Cube) and U.S. Pat. No. 4,283,372 (Frint, et al.)
disclose basic solution-mining of nahcolite and wegscheiderite
(predominately Na.sub.2CO.sub.3.3NaHCO.sub.3- ), all of which are
incorporated herein by reference. Like the trona solution-mining
processes, however, these nahcolite and wegscheiderite
solution-recovery processes also possess economic drains on
commercial viability.
[0009] A need, therefore, exists for improved solution-mining of
subterranean materials through improved, more efficient methods and
systems.
SUMMARY OF THE INVENTION
[0010] The claimed invention is a method, system, and apparatus for
solution-mining of subterranean materials. According to a first
aspect of the invention, a method is provided for solution-mining
of a subterranean material, the method comprising injecting a fluid
into an elbow well, the fluid forming a subterranean mixture with
the subterranean material, and collecting the subterranean mixture
from the elbow well. According to another aspect of the invention,
a system is provided for solution-mining of a subterranean
material, the system comprising a means for injecting a fluid into
an elbow well, the fluid forming a subterranean mixture with the
subterranean material, and a means for collecting the subterranean
mixture from the elbow well. According to still another aspect of
the invention, an apparatus is provided for solution-mining of a
subterranean material, the apparatus comprising an injection tube,
wherein the injection tube has an injection tube inner diameter of
sufficient size to allow for injection of a fluid for mining of a
subterranean material. The apparatus further comprises a production
casing, wherein the production casing has a production casing inner
diameter of sufficient size to allow for production of a
subterranean mixture of the fluid and the subterranean material
between an outer surface of the injection tube and an inner surface
of the production casing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a schematic of a cased elbow well drilled into a
bed of a subterranean material, wherein the elbow well comprises an
injection tube, a production casing, and a production tube that is
connected to a pump to help lift the subterranean mixture in the
cavity to a collection location.
[0012] FIG. 2a-1 is a cross-sectional view of the single cavity
formed in the elbow well.
[0013] FIG. 2a-2 is a plan view of the invention showing
enlargement of the elbow well's single cavity.
[0014] FIG. 2b-1 is a cross-sectional view of the cavity in the
elbow well, wherein the cavity is larger than in FIG. 2a-1.
[0015] FIG. 2b-2 is a plan view of the invention showing further
enlargement of the elbow well's cavity.
[0016] FIG. 2c-1 is a cross-sectional view of the cavity in the
elbow well, wherein the cavity is larger than in FIG. 2b-1.
[0017] FIG. 2c-2 is a plan view of the invention showing still
further enlargement of the elbow wells cavity.
DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION
[0018] The disclosed solution-mining invention is a device, method,
and system for solution-mining of subterranean materials, such as
trona, nahcolite, dawsonite, wegscheiderite, thermonatrite,
pirssonite, natron, gaylussite, shortite, halite, and other salts,
minerals, and so forth. Although this detailed disclosure focuses
on the subterranean material trona, it is understood that the
disclosed device, method, and system for solution-mining applies to
all solution-minable subterranean materials.
[0019] In one example embodiment of the claimed invention, seen in
FIG. 1, an elbow well 15 is drilled into a bed 30 of the
subterranean material 25 being mined. An elbow well 15 is a well
that begins at the earth's surface 70, and first penetrates
vertically before penetrating horizontally. Although the elbow well
15 does not necessarily resemble the shape of a human elbow, there
is a vertical portion that eventually turns to a horizontal
portion. For trona, the estimated depth 160 for mining is 2000 feet
below the earth's surface 70. Both an injection tube 45 and a
production tube 60a are located in the elbow well 15, wherein 31/2"
J55 tubing is used in one example for the injection tube 45, but
other sizes and types of tubing will occur to those of skill in the
art without departing from the scope of the present invention. A
fluid 10 is injected into the injection tube 45, wherein the fluid
10 reacts with the subterranean material 25 to create a mixture 55
(e.g., a solution) and a cavity 50. The mixture 55 flows between
the injection tube 45 and the production casing 60b. In another
example embodiment, a pump 140 is attached to the production tube
60a to help lift the mixture 55 to the collection point 65 (here,
the earth's surface 70).
[0020] Fracturing is unnecessary in many embodiments of the
invention, because the injection tube 45, production casing 60b,
and production tube 60a are in the same well 15. The elbow well 15,
in some embodiments, is over 3000 linear feet in length 155 within
the bed 30 of the subterranean material 25.
[0021] According to another embodiment of the invention, seen in
FIGS. 2a-1 through 2c-2, the cavity 50 expands as more fluid 10 is
injected into the well 15 dissolving more subterranean material 25.
The cavity 50 expands outward from the end of the elbow well 15,
and therefore the cavity 50 propagates back to the well 15. In the
event that a collapse of the cavity 50, or other obstruction,
reduces the flow of the mixture 55, the injection tube 45 is
perforated in some embodiments to permit further amounts of the
mixture 55 to be collected. Alternatively, rather than perforation,
the injection tube 45 is withdrawn, partially, until debris from
the collapse is clear and flow of the mixture 55 is raised to an
acceptable level.
[0022] High pressures of operation may cause the material 25 in the
mixture 55 to escape before collection of the subterranean material
mixture 55. Low pressures of operation, however, reduce the total
collection of the subterranean material 25, because the cavity 50
may collapse prematurely. Selection of the well pressure to avoid
these problems should be observed. At present, there is no known
empirical method to make such selection other than trial and error.
It is believed, however, that the following pressures and flow
rates are acceptable, at least for trona: at 2000 feet deep, the
pressure is 800-900 psi in the cavity 50 and the flow rate is
200-300 gal/min.
[0023] In further example embodiments of the invention, the
subterranean material 25 is selected from a group consisting
essentially of trona, dawsonite, wegscheiderite, nahcolite,
thermonatrite, pirssonite, natron, gaylussite, shortite, halite,
and other salts, minerals, and so forth.
[0024] In various example embodiments, the fluid 10 is selected
from a group consisting essentially of water, a caustic mixture, a
sodium carbonate solution, or any other fluid 10 capable of
mechanically and/or chemically reacting with the subterranean
material 25 to be mined so as to produce a mixture 55 capable of
being removed from the production casing 60b through a production
tube 60a. Such fluids 10 will occur to those of skill in the art.
In some embodiments, the fluid 10 is heated.
[0025] In a further example embodiment, the mixture 55 is lifted,
for example, by pumping with a pump 140 connected to the production
tube 60a, and the mixture 55 is delivered to a collection location
65, such as the earth's surface 70. According to one example
embodiment, an acceptable pump 140 comprises an electric
submersible centrifugal pump, 140 such as those manufactured by
Baker Hughes Centrilift. In addition, placement of the pump 140 is
above the bed 30 of subterranean mineral 25, that is, above the
mining areas. For example, with trona, the pump 140 is placed in
some embodiments about 1100 feet below the earth's surface 70 in
the elbow well 15. Other pumps 140 acceptable for use with the
claimed invention include piston/cylinder pumps, driven by sucks
rods from the surface 70. Still other pumps 140 acceptable for use
with the claimed invention will occur to those of skill in the
art.
[0026] Having thus described exemplary embodiments of the
invention, it will be apparent that various alterations,
modifications and improvements will readily occur to those skilled
in the art. Such alterations, modifications and improvements,
though not expressly described above, are nevertheless within the
spirit and scope of the invention. Accordingly, the foregoing
discussion is intended to be illustrative only, and not limiting;
the invention is limited and defined by the following claims and
equivalents thereto.
* * * * *