U.S. patent application number 12/278509 was filed with the patent office on 2009-07-09 for method and system for extraction of hydrocarbons from oil shale and limestone formations.
Invention is credited to Thomas B. O'Brien.
Application Number | 20090173491 12/278509 |
Document ID | / |
Family ID | 40843656 |
Filed Date | 2009-07-09 |
United States Patent
Application |
20090173491 |
Kind Code |
A1 |
O'Brien; Thomas B. |
July 9, 2009 |
METHOD AND SYSTEM FOR EXTRACTION OF HYDROCARBONS FROM OIL SHALE AND
LIMESTONE FORMATIONS
Abstract
A system and method for extracting hydrocarbon products from
limestone using nuclear energy sources for energy to fracture the
limestone formations and provide sufficient heat and pressure to
produce liquid and gaseous hydrocarbon products. Embodiments of the
present invention also disclose steps for extracting the
hydrocarbon products from the limestone formations.
Inventors: |
O'Brien; Thomas B.; (Blaine,
WA) |
Correspondence
Address: |
BROWN RUDNICK LLP
ONE FINANCIAL CENTER
BOSTON
MA
02111
US
|
Family ID: |
40843656 |
Appl. No.: |
12/278509 |
Filed: |
June 8, 2007 |
PCT Filed: |
June 8, 2007 |
PCT NO: |
PCT/US07/13643 |
371 Date: |
August 6, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11600992 |
Nov 17, 2006 |
7445041 |
|
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12278509 |
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60766435 |
Jan 19, 2006 |
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Current U.S.
Class: |
166/247 |
Current CPC
Class: |
E21B 43/2635
20130101 |
Class at
Publication: |
166/247 |
International
Class: |
E21B 43/24 20060101
E21B043/24; E21B 43/00 20060101 E21B043/00; E21B 36/00 20060101
E21B036/00; E21B 36/04 20060101 E21B036/04; E21B 43/26 20060101
E21B043/26 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 23, 2007 |
US |
PCT/US2007/004852 |
Claims
1. A method for recovering hydrocarbon products, the method
comprising the steps of: producing thermal energy using a nuclear
reactor; providing said thermal energy to a supercritical material
generator; providing a material to said supercritical material
generator; producing a supercritical material flow from said
supercritical material generator using a high pressure pump;
injecting said supercritical material flow into fracturing wells
wherein said fracturing wells are disposed in an limestone
formation; and fracturing said limestone formation using heat of
said supercritical material flow from said fracturing wells.
2. A method as recited in claim 1, further comprising the steps of:
providing said thermal energy to a hot gas generator; providing a
gas to said hot gas generator; producing a high pressure hot gas
flow from said hot gas generator using a high pressure pump; and
injecting said high pressure hot gas flow into injection wells
wherein said injection wells are disposed in said limestone
formation.
3. A method as recited in claim 2, further comprising the steps of:
retorting limestone in said limestone formation using heat from
said hot gas flow to produce hydrocarbon products; and extracting
said hydrocarbon products from said injection wells.
4. A method as recited in claim 3, wherein the step of extracting
includes a product recovery system coupled to said injection wells
in a configuration for collection of gaseous and liquefied
hydrocarbons released during the step of retorting.
5. A method as recited in claim 3, further comprising the step of
recovering residual gas from the step of retorting via a recycle
system, said residual gas being injected with said hot gas
generator.
6. A method as recited in claim 1, further comprising the steps of:
providing said thermal energy to a steam generator; providing water
to said steam generator; producing steam from said steam generator;
injecting said steam into a steam turbine to generate mechanical
energy; providing said mechanical energy to an electric generator;
generating current from said electric generator from said
mechanical energy; and powering electric resistance heaters with
said current, said heaters being disposed with injection wells
wherein said injection wells are disposed in said limestone
formation.
7. A method as recited in claim 6, further comprising the steps of:
retorting limestone in said limestone formation using heat from
said heaters to produce hydrocarbon products; and extracting said
hydrocarbon products from said injection wells.
8. A method as recited in claim 7, wherein the step of extracting
includes a product recovery system coupled to said injection wells
in a configuration for collection of gaseous and liquefied
hydrocarbons released during the step of retorting.
9. A method as recited in claim 1, further comprising the steps of:
providing said thermal energy to a molten salt or liquid metal
generator; providing a salt or metal to said molten salt or liquid
metal generator; producing a molten salt or liquid metal flow from
said molten salt or liquid metal generator using a pump; and
injecting said molten salt or liquid metal flow into bayonet
injection wells wherein said injection wells are disposed in said
limestone formation.
10. A method as recited in claim 9, further comprising the steps
of: retorting limestone in said limestone formation using heat from
said molten salt or liquid metal flow to produce hydrocarbon
products; and extracting said hydrocarbon products from said
injection well.
11. A method as recited in claim 10, wherein the step of extracting
includes a product recovery system coupled to said injection wells
in a configuration for collection of gaseous and liquefied
hydrocarbons released during the step of retorting.
12. A method as recited in claim 10, further comprising the step of
recovering residual salt or metal from the step of retorting via a
recycle system, said residual salt or metal being injected with
said molten salt or liquid metal generator.
13. A method as recited in claim 1, further comprising the steps
of: providing said thermal energy to a steam generator; providing
water to said steam generator; producing steam from said steam
generator; injecting said steam into a steam turbine to generate
mechanical energy; providing said mechanical energy to an electric
generator; generating current from said electric generator from
said mechanical energy; and powering oscillators with said current
to create radio frequencies to produce heat, said oscillators being
disposed with injection wells wherein said injection wells are
disposed in said limestone formation.
14. A method as recited in claim 13, further comprising the steps
of: retorting limestone in said limestone formation using heat from
said oscillators to produce hydrocarbon products; and extracting
said hydrocarbon products from said injection wells.
15. A method as recited in claim 13, wherein the step of extracting
includes a product recovery system coupled to said injection wells
in a configuration for collection of gaseous and liquefied
hydrocarbons released during the step of retorting.
16. A method as recited in claim 1, further comprising the step of
constructing an infrastructure in said limestone formation, said
infrastructure being formed by horizontal and vertical direction
drilling in a configuration to increase permeability and porosity
of said limestone formation.
17. A method for recovering hydrocarbon products, the method
comprising the steps of: producing thermal energy using a nuclear
reactor; providing said thermal energy to a hot gas generator;
providing a gas to said hot gas generator; producing a high
pressure hot gas flow from said hot gas generator using a high
pressure pump; injecting said high pressure hot gas flow into
injection wells wherein said injection wells are disposed in an
limestone formation; retorting limestone in said limestone
formation using heat from said hot gas flow to produce hydrocarbon
products; and extracting said hydrocarbon products from said
injection wells.
18. A method for recovering hydrocarbon products, the method
comprising the steps of: producing thermal energy using a nuclear
reactor; providing said thermal energy to a steam generator;
providing water to said steam generator; producing steam from said
steam generator; injecting said steam into a steam turbine to
generate mechanical energy; providing said mechanical energy to an
electric generator; generating current from said electric generator
from said mechanical energy; powering electric resistance heaters
with said current, said heaters being disposed with injection wells
wherein said injection wells are disposed in an limestone
formation; retorting limestone in said limestone formation using
heat from said heaters to produce hydrocarbon products; and
extracting said hydrocarbon products from said injection wells.
19. A method for recovering hydrocarbon products, the method
comprising the steps of: producing thermal energy using a nuclear
reactor; providing said thermal energy to a molten salt or liquid
metal generator; providing a salt or metal to said molten salt or
liquid metal generator; producing a molten salt or liquid -metal
flow from said molten salt or liquid metal generator using a pump;
injecting said molten salt or liquid metal flow into bayonet
injection wells wherein said injection wells are disposed in an
limestone formation; retorting limestone in said limestone
formation using heat from said molten salt or liquid metal flow to
produce hydrocarbon products; and extracting said hydrocarbon
products from said injection well.
20. A method for recovering hydrocarbon products, the method
comprising the steps of: producing thermal energy using a nuclear
reactor; providing said thermal energy to a steam generator;
providing water to said steam generator; producing steam from said
steam generator; injecting said steam into a steam turbine to
generate mechanical energy; providing said mechanical energy to an
electric generator; generating current from said electric generator
from said mechanical energy; powering oscillators with said current
to create radio frequencies to produce heat, said oscillators being
disposed with injection wells wherein said injection wells are
disposed in a limestone formation; retorting limestone in said
limestone formation using heat from said oscillators to produce
hydrocarbon products; and extracting said hydrocarbon products from
said injection wells.
21. A method as recited in claim 1, wherein the step of injecting
includes said fracturing wells being disposed in a formation
including limestone and oil shale.
22. A method as recited in claim 3, wherein the step of retorting
includes retorting oil shale and limestone.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This patent application is a continuation-in-part of U.S.
patent application Ser. No. 11/600,992, filed on Nov. 17, 2006 and
International Patent Application No. PCT/US07/04852, filed on 23
Feb. 2007. U.S. patent application Ser. No. 11/600,992 claims the
benefit of U.S. Provisional Patent Application Ser. No. 60/765,667,
filed on Feb. 6, 2006 and International Patent Application No.
PCT/US07/04852 claims the benefit of U.S. Provisional Patent
Application Ser. No. 60/766,435, filed on Feb. 24, 2006, the
contents of each of these references being incorporated herein by
reference in their entireties.
FIELD OF THE INVENTION
[0002] The present invention relates to using alternative energy
sources to create a method and system that minimizes the cost of
producing useable hydrocarbons from hydrocarbon-rich shales or "oil
shales" and "limestone" geologic formations. The advantageous
design of the present invention, which includes a system and method
for the recovery of hydrocarbons, provides several benefits
including minimizing energy input costs, limiting water use and
reducing the emission of greenhouse gases and other emissions and
effluents, such as carbon dioxide and other gases and liquids.
BACKGROUND OF THE INVENTION
[0003] Discovery of improved and economical systems and methods for
extracting hydrocarbons from organic-rich rock formations, such as
oil shale and limestone formations, has been a challenge for many
years. Historically, a substantial amount of hydrocarbons are
produced from subterranean reservoirs.
[0004] The reservoirs can include organic-rich shale and limestone
formations from which the hydrocarbons derive. The shale contains a
hydrocarbon precursor known as kerogen. Kerogen is a complex
organic material that can mature naturally to hydrocarbons when it
is exposed to temperatures over 100.degree. C. This process,
however, can be extremely slow and takes place over geologic
time.
[0005] Immature oil shale formations are those that have yet to
liberate their kerogen in the form of hydrocarbons. These organic
rich rock formations represent a vast untapped energy source. The
kerogen, however, must be recovered from the oil shale formations,
which under prior known methods can be a complex and expensive
undertaking, which may have a negative environmental impact such as
greenhouse gases and other emissions and effluents, such as carbon
dioxide and other gases and liquids.
[0006] In a known method, kerogen-bearing oil shale near the
surface can be mined and crushed and, in a process known as
retorting, the crushed shale can then be heated to high
temperatures to convert the kerogen to liquid hydrocarbons. There
are, however, a number of drawbacks to surface production of shale
oil including high costs of mining, crushing, and retorting the
shale and a negative environmental impact, which also includes the
cost of shale rubble disposal, site remediation and cleanup. In
addition, many oil shale deposits are at depths that make surface
mining impractical.
[0007] In other methods, oil occurs in certain geologic formations
at varying depths in the earth's crust. In many cases elaborate,
expensive equipment is required for recovery. The oil is usually
found trapped in a layer of porous sandstone, which lies beneath a
dome-shaped or folded layer of some non-porous rock such as
limestone. In other formations, the oil is trapped at a fault, or
break in the layers of the crust.
[0008] In the dome and folded formations of the limestone, natural
gas is usually present below the non-porous layer and immediately
above the oil. Below the oil layer, the sandstone is usually
saturated with salt water. The oil is released from this formation
by drilling a well and puncturing the limestone layer on either
side of the limestone dome or fold.
[0009] Attempts have been made to overcome the drawbacks of prior
known methods of recovery by employing in situ (i.e., "in place")
processes. In situ processes can include techniques whereby the
kerogen in oil shale is subjected to in situ heating through
combustion, heating with other material or by electric heaters and
radio frequencies in the shale formation itself. The shale is
retorted and the resulting oil drained to the bottom of the rubble
such that the oil is produced from wells. In still other attempts,
in situ techniques have been described that include fracturing and
heating the shale formations and limestone formations underground
to release gases and oils. These types of techniques typically
require finished hydrocarbons to produce thermal and electric
energy and heat the shale and limestone formations, and may employ
conventional hydro-fracturing techniques or explosive materials.
These attempts, however, also continue to suffer from disadvantages
such as negative environmental impacts, high fuel costs to produce
thermal energy for heating and/or electricity, as well as high
water consumption. In addition, these methods may have a negative
environmental impact such as greenhouse gases and other emissions
and effluents, such as carbon dioxide and other gases and
liquids.
[0010] Therefore, it would be desirable to overcome the
disadvantages and drawbacks of the prior art with a method and
system for recovering hydrocarbon products from rock formations,
such as oil shale and limestone formations, which fracture the
formation and heat the oil shale and/or limestone via thermal or
electrically induced energy produced by a nuclear reactor. It would
be desirable if the method and system can accelerate the maturation
process of the precursors of crude oil and natural gas. It is most
desirable that the method and system of the present invention is
advantageously employed to minimize energy input costs, limit water
use and reduce the emission of greenhouse gases and other emissions
and effluents, such as carbon dioxide and other gases and
liquids.
SUMMARY OF THE INVENTION
[0011] Accordingly, a method and system is disclosed for recovering
hydrocarbon products from rock formations, such as oil shale and
limestone formations, which fracture the formation and heat the oil
shale and/or limestone via thermal energy produced by a nuclear
reactor for overcoming the disadvantages and drawbacks of the prior
art. Desirably, the method and system can accelerate the maturation
process of the precursors of crude oil and natural gas. The method
and system may be advantageously employed to minimize energy input
costs, limit water use and reduce the emission of greenhouse gases
and other emissions and effluents, such as carbon dioxide and other
gases and liquids. It is envisioned that the enhanced fracturing
technologies disclosed can greatly increase the efficiency of
producing oil from these limestone formations.
[0012] In the method and system it is contemplated that
supercritical material will be injected into the oil shale and/or
limestone formations to produce fracturing and porosity that will
maximize the production of useful hydrocarbons from the oil shale
formation and limestone formations.
[0013] In one particular embodiment, in accordance with the present
disclosure, a method for recovering hydrocarbon products is
provided. The method includes the steps of: producing thermal
energy using a nuclear reactor; providing the thermal energy to a
hot gas generator; providing a gas to the hot gas generator;
producing a high pressure hot gas flow from the hot gas generator
using a high pressure pump; injecting the high pressure hot gas
flow into injection wells wherein the injection wells are disposed
in a limestone formation; retorting limestone in the limestone
formation using heat from the hot gas flow to produce hydrocarbon
products; and extracting the hydrocarbon products from the recovery
well. It is contemplated that the method, and the alternative
embodiments discussed, include the injection wells, which may be
disposed in rock formations that include oil shale and limestone,
whereby oil shale and limestone is retorted. It is further
contemplated that such rock formations only include oil shale.
[0014] In an alternate embodiment, the method includes the steps
of: generating electricity using a nuclear powered steam turbine;
retorting limestone in a limestone formation using electric heaters
powered by the electricity to produce hydrocarbon products; and
extracting the hydrocarbon products from the injection well.
[0015] In another alternate embodiment, the method includes the
steps of: producing thermal energy using a nuclear reactor;
providing the thermal energy to a molten salt or liquid metal
generator; providing a salt or metal to the molten salt or liquid
metal generator; producing a molten salt or liquid metal flow from
the molten salt or liquid metal generator using a pump; injecting
the molten salt or liquid metal flow into bayonet injection wells
wherein the injection wells are disposed in a limestone formation;
retorting limestone in limestone formation using heat from the
molten salt or liquid metal flow to produce hydrocarbon products;
and extracting the hydrocarbon products from the recovery well.
[0016] In another alternate embodiment, the method includes the
steps of: generating electricity using a nuclear powered steam
turbine; retorting in a limestone formation using radio frequencies
powered by the electricity to produce hydrocarbon products; and
extracting the hydrocarbon products from the recovery well.
[0017] The present invention provides a system and method for
extracting hydrocarbon products from oil shale and/or limestone
formations using nuclear reactor sources for energy to fracture the
oil shale formations and/or limestone formations and provide
sufficient heat and/or electric power to produce liquid and gaseous
hydrocarbon products. Embodiments of the present invention also
disclose steps for extracting the hydrocarbon products from the oil
shale and/or limestone formations.
[0018] Oil shale and limestone contain the precursors of crude oil
and natural gas. The method and system can be employed to
artificially speed the maturation process of these precursors by
first fracturing the formation using supercritical materials to
increase both porosity and permeability, and then heat the shale
and/or limestone to increase the temperature of the formation above
naturally occurring heat created by an overburden pressure. The use
of a nuclear reactor may reduce energy input cost as compared to
employing finished hydrocarbons to produce thermal energy and/or
electricity. Nuclear reactors produce the supercritical temperature
in the range from 200.degree. to 1100.degree. C. (depending on the
material to be used) necessary for increasing the pressure used in
the fracturing process compared to conventional hydro fracturing
and/or the use of explosives. In oil shale and limestone
formations, the maximization of fracturing is advantageous to
hydrocarbon accumulation and recovery. Generally, massive shales
and limestone formations in their natural state have very limited
permeability and porosity.
[0019] In addition, limiting water use is also beneficial. The use
of large quantities of water has downstream implications in terms
of water availability and pollution. The method and system may
significantly reduce water use.
[0020] Further, the use of natural gas/coal/oil for an input energy
source creates greenhouse gases and other emissions and effluents,
such as carbon dioxide and other gases. An increasingly large
number of earth scientists believe that greenhouse gases contribute
to a phenomenon popularly described as "global warming". The method
and system of the present disclosure can significantly reduce the
emission of greenhouse gases.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The present invention, both as to its organization and
manner of operation, will be more fully understood from the
following detailed description of illustrative embodiments taken in
conjunction with the accompanying drawings in which:
[0022] FIG. 1 is a schematic diagram of a method and system for
fracturing oil shale and/or limestone formations using a nuclear
energy source in accordance with the principles of the present
invention;
[0023] FIG. 2 is a schematic diagram of directionally drilled
shafts used at an extraction site, in accordance with the
principles of the present invention;
[0024] FIG. 3 is a process energy flow diagram of the method and
system shown in FIG. 1;
[0025] FIG. 4 is a schematic diagram of a method and system for
retorting oil shale and/or limestone using a nuclear energy source
in accordance with the principles of the present invention;
[0026] FIG. 5 is a process energy flow diagram of the method and
system shown in FIG. 4;
[0027] FIG. 6 is a schematic diagram of an alternate embodiment of
the method and system shown in FIG. 4;
[0028] FIG. 7 is a process energy flow diagram of the method and
system shown in FIG. 6;
[0029] FIG. 8 is a schematic diagram of an alternate embodiment of
the method and system shown in FIG. 4;
[0030] FIG. 9 is a process energy flow diagram of the method and
system shown in FIG. 8;
[0031] FIG. 10 is a schematic diagram of an alternate embodiment of
the method and system shown in FIG. 4; and
[0032] FIG. 11 is a process energy flow diagram of the method and
system shown in FIG. 10.
DETAILED DESCRIPTION
[0033] The exemplary embodiments of the method and system for
extracting hydrocarbon products using alternative energy sources to
fracture oil shale formations and/or limestone formations and heat
the oil shale and/or limestone to produce liquid and gaseous
hydrocarbon products are discussed in terms of recovering
hydrocarbon products from rock formations and more particularly, in
terms of recovering such hydrocarbon products from the oil shale
and limestone formations via thermal energy produced by a nuclear
reactor. The method and system of recovering hydrocarbons may
accelerate the maturation process of the precursors of crude oil
and natural gas. It is contemplated that such a method and system
as disclosed herein can be employed to minimize energy input costs,
limit water use and reduce the emission of greenhouse gases and
other emissions and effluents, such as carbon dioxide and other
gases and liquids. The use of a nuclear reactor to produce thermal
energy reduces energy input costs and avoids reliance on finished
hydrocarbon products to produce thermal energy and the related
drawbacks associated therewith and discussed herein. It is
envisioned that the present disclosure may be employed with a range
of recovery applications for oil shale and/or limestone extraction
including other in situ techniques, such as combustion and
alternative heating processes, and surface production methods. It
is further envisioned that the present disclosure may be used for
the recovery of materials other than hydrocarbons or their
precursors disposed in subterranean locations.
[0034] The following discussion includes a description of the
method and system for recovering hydrocarbons in accordance with
the principles of the present disclosure. Alternate embodiments are
also disclosed. Reference will now be made in detail to the
exemplary embodiments of the present disclosure, which are
illustrated in the accompanying figures. Turning now to FIG. 1,
there is illustrated a method and system for recovering hydrocarbon
products, such as, for example, a system 20 for fracturing and
retorting oil shale and/or limestone using a nuclear reactor and an
associated thermal transfer system, in accordance with the
principles of the present disclosure.
[0035] The nuclear reactor and thermal components of system 20 are
suitable for recovery applications. Examples of such nuclear
reactor and thermal components are provided herein, although
alternative equipment may be selected and/or preferred, as
determined by one skilled in the art.
[0036] Detailed embodiments of the present disclosure are disclosed
herein, however, it is to be understood that the described
embodiments are merely exemplary of the disclosure, which may be
embodied in various forms. Therefore, specific functional details
disclosed herein are not to be interpreted as limiting, but merely
as a basis for the claims and as a representative basis for
teaching one skilled in the art to variously employ the present
disclosure in virtually any appropriately detailed embodiment.
[0037] In one aspect of system 20 and its associated method of
operation, a limestone extraction site 22 is selected for recovery
of hydrocarbon products and treatment of the precursors of oil and
gas. It is envisioned that system 20 and its associated method, and
the alternate embodiments discussed below, may be employed with an
extraction site, which includes oil shale and limestone formations
for recovery of hydrocarbon products and precursors. It is further
envisioned that such an extraction site may only include oil shale
formations.
[0038] Site selection will be based on subsurface mapping using
existing borehole data such as well logs and core samples and
ultimately data from new holes drilled in a regular grid. Areas
with higher concentrations of relatively mature kerogen, and
limestone formations and lithology favorable to fracturing will be
selected. Geophysical well log data where available, including
resistivity, conductivity, sonic logs and so on will be employed.
Seismic data is desirable; however, core analysis is a reliable
method of determining actual porosity and permeability which is
related to both efficient heating and extraction of the end
product, usable hydrocarbons. Grain size and distribution is also
desirable. Areas where there is high drilling density and reliable
data with positive indications in the data would be ideal.
Geochemical analysis is also desirable to the process as limestone
formations tend to have very complicated geochemical
characteristics. Surface geochemistry is desirable in a localized
sense. Structural features and depositional environments are
desirable in a more area or regional sense. Reconstruction of
depositional environments and post-depositional dynamics are
desirable. Three dimensional computer modeling provided there is
enough accurate data would be desirable. As experience is gained in
the optimal parameters for exploitation, the entire process and
system can be modulated in its application to different sub-surface
environments.
[0039] At selected site 22, a surface level 24 is drilled for
extraction of core samples (not shown) using suitable drilling
equipment for a rock formation application, as is known to one
skilled in the art. The core samples are extracted from site 22 and
geological information is taken from the core samples. These core
samples are analyzed to determine if site 22 selected is suitable
for recovery of hydrocarbons and treatment of the precursors of oil
and gas.
[0040] If the core samples have the desired characteristics, site
22 will be deemed suitable for attempting to extract hydrocarbons
from limestone formations. Alternatively, site 22 may be deemed
suitable for extraction of limestone and oil shale, or oil shale
only. Accordingly, a strategy and design is formulated for
constructing fracturing wells and retort injection wells, as will
be discussed below. Joints, fractures and depositional weaknesses
will be exploited in order to maximize the effect of this method of
fracturing. Ideally areas can be identified which have experienced
a relatively higher degree of naturally occurring fracturing due to
folding and faulting as observed in the coastal areas of central
California. Piping arrays will be oriented in concert with these
existing weaknesses in order to create the maximum disruption of
the rock matrix. The nuclear reactor placement will also be
formulated and planned for implementation, as well any other
infrastructure placements necessary for implementation of the
system and method. It is contemplated that if the core samples
taken from the selected site are not found to have the desired
characteristics, an alternate site may be selected. Site 22 is also
prepared for installation and related construction of a
supercritical material generator 28 and other components including
high pressure pumps 30 and drilling equipment (not shown).
[0041] In another aspect of system 20, installation and related
construction of nuclear reactor 26 and the components of the
thermal transfer system at site 22 is performed. Plumbing equipment
(not shown) is constructed and installed. A material supply 34 is
connected to the plumbing equipment and the components of the
thermal transfer system. Electrical equipment (not shown) is wired
and installed. Off-site electric connections (if available) are
made to the electrical equipment. If off-site electric connections
are not available, then a small stream of energy from the nuclear
reactor may be generated using a conventional electric generator
(not shown). It is contemplated that plumbing equipment and
electrical equipment are employed that are suitable for an oil
shale and/or limestone formation extraction application and more
particularly, for recovery of hydrocarbons and treatment of their
precursors, as is known to one skilled in the art.
[0042] It is envisioned that nuclear reactor 26 may be a small or
large scale nuclear reactor employed with system 20 in accordance
with the principles of the present disclosure. Nuclear reactor 26
is a thermal source used to provide thermal energy 32 to fracture
an oil shale formation and/or limestone formations (not shown).
Nuclear reactor 26 is sized to be located at or near the oil shale
formation and/or limestone formations of site 22. It is envisioned
that the thermal rating of nuclear reactor 26 is between 20 MWth to
3000 MWth. For example, a nuclear reactor, such as the Toshiba 4S
reactor, may be used. These reactors can include all generation
III, III+ and IV reactors, including but not limited to Pressurized
Water Reactors, Boiling Water Reactors, CANDU reactors, Advanced
Gas Reactors, ESBWR, Very High Temperature Reactors, helium or
other gas cooled reactors, liquid sodium cooled reactors, liquid
lead cooled rectors or other liquid metal cooled reactors, molten
salt reactors, Super Critical Water Reactors, and all next
generation nuclear plant designs.
[0043] Supercritical material generator 28 is constructed and
installed at site 22. Nuclear reactor 26 is coupled to
supercritical material generator 28, as is known to one skilled in
the art, for the transfer of thermal energy 32. Material supply
source 34 delivers material 35 to supercritical material generator
28. System 20 employs supercritical material generator 28, in
cooperation with nuclear reactor 26 as the thermal source, to
produce supercritical material 36 for fracturing oil shale
formations and/or limestone formations. It is contemplated that a
number of materials may be generated by supercritical material
generator 28 for fracturing, such as water, carbon dioxide and
nitrogen, among others.
[0044] The use of supercritical material 36 is employed to enhance
permeability and porosity of an oil shale formation and/or
limestone formations through fracturing. Studies have shown that
supercritical material can be effectively used to permeate and
fracture rock formations. (See, e.g., 14th International Conference
on the Properties of Water and Steam in Kyoto, Sergei Fomin*,
Shin-ichi Takizawa and Toshiyuki Hashida, Mathematical Model of the
Laboratory Experiment that Simulates the Hydraulic Fracturing of
Rocks under Supercritical Water Conditions, Fracture and
Reliability Research Institute, Tohoku University, Sendai 980-8579,
Japan), which is incorporated herein in its entirety. Other
supercritical material has been used in other applications.
[0045] Systems to manage the extremely high pressures must be
installed in order to safely operate the entire apparatus.
Placement of blowout preventers and pressure relief valves will be
integrated into the system and carefully monitored particularly at
the outset of testing the process.
[0046] High pressure pumps 30 are installed at site 22 and coupled
to supercritical material generator 28 for injecting supercritical
material 36 into the limestone formations. High pressure pumps 30
deliver supercritical material 36 to the limestone formations
fracturing wells 38 at high pressure. Supercritical material 36 is
delivered at high pressures to the limestone formations to achieve
maximum permeability therein. It is envisioned that high pressure
pumps 30 deliver pressures in the range between 50 and 500 MPa or
higher. These pumps may be centrifugal or other types of pumps. The
high pressure pumps and required remote pumping stations (not
shown) may be designed for remote operation using the pipeline
SCADA (Supervisory Control And Data Acquisition) systems and may be
equipped with protection equipment such as intake and discharge
pressure controllers and automatic shutoff devices in case of
departure from design operating conditions. Alternatively, pumps 30
may be installed at site 22 having limestone and oil shale
formations, or only oil shale.
[0047] It is further envisioned that an optimal injection
parameters can be determined based on the formation characteristics
and other factors. Geologic environments can vary locally and
regionally. As well as discussed above, system 20 may include
various high pressure pump configurations such as a series of
multiple pumps to achieve optimal results. The described
supercritical material distribution system is constructed and
installed at site 22, as is known to one skilled in the art. All
systems are tested and a shakedown integration is performed.
[0048] An infrastructure 39 for fracturing wells 38 (FIG. 1) is
constructed at site 22, as shown in FIG. 2. A drilling rig 40 with
equipment designed for accurate directional drilling is brought on
site. It will be very important to accurately determine the
location of the bit while drilling. Many recent innovations in rig
and equipment design make this possible. Rigs may be leased on a
day or foot rate and are brought in piece by piece for large rigs
and can be truck mounted for small rigs. Truck mounted rigs can
drill to depths of 2200 feet or more 24 of site 22, as is known to
one skilled in the art. Drilling rig 40 is disposed adjacent a
vertical drill hole 42 from which horizontal drill holes 44, which
may be disposed at orthogonal, angular or non-orthogonal
orientations relative to vertical drill hole 42, are formed.
Limestone formation fracturing wells 38 are installed with
infrastructure 39 of site 22. Limestone formation fracturing wells
38 inject supercritical material 36 into drill holes 42, 44 of the
limestone formation and site 22. Alternatively, wells 38 may be
configured for limestone and oil shale formations, or only oil
shale.
[0049] Directional drilling is employed to maximize the increase in
permeability and porosity of the oil shale formation and/or
limestone formations and maximize the oil shale formation and/or
limestone formation's exposure to induced heat. The configuration
of horizontal drill holes 44 can be formulated based on geological
characteristics of the oil shale formation and limestone formations
as determined by core drilling and geophysical investigation. These
characteristics include depositional unconformities, orientation of
the bedding planes, schistosity, as well as structural disruptions
within the formations as a consequence of tectonics. Existing
weaknesses in the oil shale formations and/or limestone formations
may be exploited including depositional unconformities, stress
fractures and faulting.
[0050] An illustration of the energy flow of system 20 for the
limestone formations fracturing operations (FIG. 1), as shown in
FIG. 3, includes nuclear energy 46 generated from nuclear reactor
26. Nuclear energy 46 creates thermal energy 32 that is transferred
to supercritical material generator 28 for producing supercritical
material 36. Supercritical material 36 is delivered to high
pressure pumps 30. Pump energy 48 puts supercritical material 36
under high pressure.
[0051] High pressure pumps 30 deliver supercritical material 36 to
fracturing wells 38 with sufficient energy 50 to cause fracturing
in the limestone formations. Such fracturing force increases
porosity and permeability of the limestone formations through
hydraulic stimulation under supercritical conditions. Residual
supercritical materials from the fracturing operations are
recovered via a material recovery system 45 and re-introduced to
supercritical material generator 28 via material supply 34 using
suitable conduits, as known to one skilled in the art. It is
envisioned that a material recovery system is employed to minimize
the consumption of material used to fracture the limestone
formations. A recycling system may be deployed in order to also
minimize any groundwater pollution and recycle material where
possible.
[0052] In another aspect of system 20, the fracturing operations
employing the supercritical material distribution system described
and limestone formations fracturing wells 38 are initiated. Nuclear
reactor 26 and the material distribution system are run. Fracturing
of the limestone formations via wells 38 is conducted to increase
permeability and porosity of the limestone formations for heat
inducement. The fracturing process in the limestone formation at
site 22 is tracked via readings taken. Based on these reading
values, formulations are conducted to determine when the fracturing
is advanced to a desired level. One method of determining the level
of fracturing would be take some type of basically inert material,
circulate it downhole, and read the amount and rate of material
loss. In other words, measure the "leakage" into the formation.
Gases may also be employed with the amount of pressure loss being
used to measure the degree of fracturing. These measurements would
be compared to "pre-fracturing" level. This method would be
particularly helpful in the case of microfracturing. Core samples
are extracted from the fractured limestone formations. These
samples are analyzed. The analysis results are used to formulate
and plan for implementation of a drilling scheme for the injection
wells for retort and perforation wells for product recovery.
Alternatively, the discussed fracturing operations may be employed
with limestone and oil shale formations, or only oil shale.
[0053] In another aspect of system 20, limestone fracturing wells
38 are dismantled from infrastructure 39. Initially, operation of
nuclear reactor 26 is temporarily discontinued in cold or hot
shutdown depending on the particular reactor's characteristics.
Limestone formations fracturing wells 38 are dismantled and removed
from infrastructure 39 of site 22. Retort wells and perforation
recovery wells (not shown) are constructed with infrastructure 39,
in place of the limestone formations fracturing wells 38, and
installed at site 22 for connection with drill holes 42, 44.
Exemplary embodiments of retort systems for use with system 20, in
accordance with the principles of the present disclosure, will be
described in detail with regard to FIGS. 4-11 discussed below.
[0054] The retort wells transfer heated materials to the fractured
limestone formations for heat inducement. The exposure of the
limestone to heat in connection with high pressure accelerates the
maturation of the hydrocarbon precursors, such as kerogen, which
forms liquefied and gaseous hydrocarbon products. In limestone
formations, oil can be extracted using conventional techniques.
During the retort operations, hydrocarbons accumulate. A suitable
recovery system is constructed for hydrocarbon recovery, as will be
discussed. Nuclear reactor 26 is restarted for retort operations,
as described. All systems are tested and a shakedown integration is
performed.
[0055] In another aspect of system 20, the retort operations
employing the retort wells and perforation recovery wells are
initiated for product recovery. The retort wells and the
perforation wells are run and operational. In one particular
embodiment, as shown in FIG. 4, system 20 includes a retort system
120 for retort operations relating to the fractured limestone
formations at site 22, similar to that described with regard to
FIGS. 1-3. Site 22 is prepared for installation and related
construction of retort system 120, which includes gas handling
equipment and thermal transfer system components, which will be
described.
[0056] Retort system 120 employs hot gases that are injected into
the fractured limestone formations to induce heating and accelerate
the maturation process of hydrocarbon precursors as discussed.
Nuclear reactor 26 discussed above, is a thermal source that
provides thermal energy 132 to retort the limestone formation
in-situ. Nuclear reactor 26 is sized to be located at or near site
22 of the fractured limestone formation. It is envisioned that the
thermal rating of nuclear reactor 26 is between 20 MWth to 3000
MWth. It is further contemplated that hydrogen generated by nuclear
reactor 26 can be used to enhance the value of carbon bearing
material, which may resemble char and be recoverable. A hydrogen
generator (not shown), either electrolysis, thermal or other may be
attached to the nuclear reactor 26 to generate hydrogen for this
use. Alternatively, the retort wells and recovery wells may be
employed with limestone and oil shale formation applications, or
only oil shale.
[0057] A gas injection system 134 is installed at site 22. Gas
injection system 134 delivers gas to a hot gas generator 128. Hot
gas generator 128 is constructed and installed at site 22. There
are many types of hot gas generators available for this type of
application including, but not limited to boilers and the like.
Nuclear reactor 26 is coupled to hot gas generator 128, as is known
to one skilled in the art, for the transfer of thermal energy 132.
System 20 employs hot gas generator 128, in cooperation with
nuclear reactor 26 as the thermal source, to produce hot gas 136
for retort of the fractured limestone formations.
[0058] It is envisioned that the thermal output of nuclear reactor
26 can be used to heat various types of gases for injection to
retort the oil shale and/or limestone formations such as air,
carbon dioxide, oxygen, nitrogen, methane, acetic acid, steam or
other appropriate gases other appropriate combinations. Other gases
can also be injected secondarily to maximize the retort process if
appropriate.
[0059] High pressure pumps 130 are installed at site 22 and coupled
to hot gas generator 128 for injecting hot gas 136 into the
fractured limestone formations. High pressure pumps 130 put hot gas
136 into a high pressure state to promote the retort of the
limestone formations. It is envisioned that system 20 may include
various high pressure pump configurations including multiple pumps
and multiple gases to maximize the effectiveness of the retort
operation.
[0060] Limestone asset heating retort injection wells 138 are
installed with the infrastructure of system 20, as discussed. Hot
gas 136 is transferred to injection wells 138 and injected into the
fractured limestone formation. The use of horizontal drilling
described with regard to FIG. 3, can be employed to maximize the
limestone and/or oil shale formation's exposure to heat necessary
to form both gaseous and liquefied hydrocarbons. It may take
between 2-4 years for the formation of sufficient kerogen to be
commercially recoverable. After that recovery may occur on a
commercial level for between 3-30 years or more.
[0061] A product recovery system 160 is constructed at site 22.
Product recovery system 160 may be a conventional hydrocarbon
recovery system or other suitable system that addresses the
recovery requirements and is coupled with perforation recovery
wells 120 (not shown) for collection of gaseous and liquefied
hydrocarbons that are released during the retort process. An
illustration of the energy flow of system 20 with retort system 120
for limestone retorting operations (FIG. 4), as shown in FIG. 5,
includes nuclear energy 146 generated from nuclear reactor 26. Gas
is delivered from gas injection system 134 to hot gas generator
128. Nuclear energy 146 creates thermal energy 132 that is
transferred to hot gas generator 128 for producing hot gas 136. Hot
gas 136 is delivered to high pressure pumps 130. Pump energy 148
puts hot gas 136 under high pressure.
[0062] High pressure pumps 130 deliver hot gas 136 to retort
injection wells 138 with sufficient energy 150 to transfer hot gas
136 to the fractured limestone formations for heat inducement for
retort operations. The exposure of the limestone to heat in
connection with high pressure accelerates the maturation of the
hydrocarbon precursors, such as kerogen, which forms liquefied and
gaseous hydrocarbons. During the retort operations, hydrocarbon
products 162 accumulate. Hydrocarbon products 162 are extracted and
collected by product recovery system 160. Residual gas from the
retorting operations is recovered via a gas recycle system 145 and
reinjected to hot gas generator 128 via gas injection system 134.
It is envisioned that a gas recovery system is employed to minimize
the consumption of gas used to retort the fractured limestone
formation.
[0063] In an alternate embodiment, as shown in FIG. 6, system 20
includes a retort system 220 for retort operations relating to the
fractured limestone formations at site 22, similar to those
described. Site 22 is prepared for installation and related
construction of retort system 220, which includes a steam generator
and thermal transfer system components, as will be described.
[0064] Retort system 220 employs heat generated by electric heaters
inserted into holes drilled into the fractured limestone formations
of site 22. The heat generated induces heating of the fractured
limestone formations to accelerate the maturation process of
hydrogen precursors, as discussed. Nuclear reactor 26 discussed
above, is a thermal source that cooperates with a steam generator
228 to power a steam turbine 230 for generating steam that may be
used to drive an electric generator 234 to produce the electric
energy to retort the fractured limestone formation in-situ. If a
conventional pressurized water reactor or similar non-boiling water
reactor is used, a heat exchanger (not shown) may be required.
Nuclear reactor 26 is sized to be located at or near site 22 of the
fractured limestone formation. It is envisioned that the electric
capacity rating of nuclear reactor 26 is between 50 MWe to 2000
MWe. It is contemplated that the hydrogen generated by nuclear
reactor 26 can be used to enhance the value of carbon bearing
material, which may resemble char, so it will be recoverable. A
hydrogen generator (not shown), either electrolysis, thermal or
other may be attached to the nuclear reactor 26 to generate
hydrogen for this use.
[0065] Water supply 34 delivers water to steam generator 228, which
is constructed and installed at site 22. Nuclear reactor 26 is
coupled to steam generator 228, as is known to one skilled in the
art, for the transfer of thermal energy 232. System 20 employs
steam generator 228, in cooperation with nuclear reactor 26 as the
thermal source, to produce steam 236 to activate steam turbine 230
for operating an electric generator to provide electric energy for
the retort of the fractured limestone formations. If a conventional
pressurized water reactor or similar non-boiling water reactor is
used a heat exchanger (not shown) may be required.
[0066] Steam generator 228 is coupled to steam turbine 230, in a
manner as is known to one skilled in the art. Steam 236 from steam
generator 228 flows into steam turbine 230 to provide mechanical
energy 237 to an electric generator 234. Steam turbine 230 is
coupled to electric generator 234, in a manner as is known to one
skilled in the art, and mechanical energy 237 generates current 239
from electric generator 234. It is contemplated that current 239
may include alternating current or direct current.
[0067] Current 239 from electric generator 234 is delivered to
limestone asset electric heating retort injection wells 238.
Injection wells 238 employ electric resistance heaters (not shown),
which are mounted with holes drilled into the fractured limestone
formations of site 22, to promote the retort of the limestone. The
electric resistance heaters heat the subsurface of fractured
limestone formations to approximately 343 degrees C. (650 degrees
F.) over a 3 to 4 year period. Upon duration of this time period,
production of both gaseous and liquefied hydrocarbons are recovered
in a product recovery system 260.
[0068] Product recovery system 260 is constructed at site 22.
Product recovery system 260 is coupled with injection wells 238 or
perforation recovery wells for collection of gaseous and liquefied
hydrocarbons that are released during the retort process. An
illustration of the energy flow of system 20 with retort system 220
(FIG. 6) for limestone retorting operations, as shown in FIG. 7,
includes nuclear energy 246 generated from nuclear reactor 26.
Nuclear energy 246 creates thermal energy 232 that is transferred
to steam generator 228 for producing steam 236. If a conventional
pressurized water reactor or similar non-boiling water reactor is
used a heat exchanger (not shown) may be required. Steam 236 is
delivered to steam turbine 230, which produces mechanical energy
237. Mechanical energy 237 generates current 239 from electric
generator 234.
[0069] Current 239 delivers electric energy 241 to the electric
heating elements to heat the fractured limestone formations for
heat inducement. The exposure of the limestone to heat accelerates
the maturation of the hydrocarbon precursors, such as kerogen,
which forms liquefied and gaseous hydrocarbons. During the retort
operations, hydrocarbon products accumulate. The hydrocarbon
products are extracted and collected by product recovery system
260. Alternatively, retort system 220, product recovery system 260,
and related components may be employed with limestone and oil shale
formation applications, or only oil shale.
[0070] In another alternate embodiment, as shown in FIG. 8, system
20 includes a retort system 320 for retort operations relating to
the fractured limestone formations at site 22, similar to that
described. Site 22 is prepared for installation and related
construction of retort system 320, which includes a molten salt or
liquid metal generator, bayonet heaters and thermal transfer system
components, which will be described.
[0071] Retort system 320 employs molten salts or liquid metal,
which are injected into the fractured limestone formations to
accelerate the maturation process of hydrocarbon precursors as
discussed. Nuclear reactor 26 is a thermal source that provides
thermal energy 332 to retort the fractured limestone formation
in-situ. Nuclear reactor 26 is sized to be located at or near site
22 of the fractured limestone formation. It is envisioned that the
thermal rating of nuclear reactor 26 is between 20 MWth to 3000
MWth. It is further contemplated that hydrogen generated by nuclear
reactor 26 can be used to enhance the value of carbon bearing
material, which may resemble char and be recoverable. A hydrogen
generator (not shown), either electrolysis, thermal or other may be
attached to the nuclear reactor 26 to generate hydrogen for this
use.
[0072] A salt injection system 334 is installed at site 22. Salt
injection system 334 delivers salts to a molten salt generator 328.
Molten salt generator 328 is constructed and installed at site 22.
Nuclear reactor 26 is coupled to molten salt generator 328, as is
known to one skilled in the art, for the transfer of thermal energy
332. System 20 employs molten salt generator 328, in cooperation
with nuclear reactor 26 as the thermal source, to produce molten
salt 336 for retort of the fractured limestone formations.
[0073] It is envisioned that the thermal output of nuclear reactor
26 can be used to heat various types of salts for injection to
retort the limestone, such as halide salts, nitrate salts, fluoride
salts, and chloride salts. It is further envisioned that liquid
metals may be used with retort system 320 as an alternative to
salts, which includes the use of a metal injection system and a
liquid metal generator. The thermal output of nuclear reactor 26
can be used to heat various types of metals for injection to retort
the limestone, including alkali metals such as sodium.
[0074] Pumps 330 are installed at site 22 and coupled to molten
salt generator 328 for injecting molten salt 336 into the fractured
limestone formations. Pumps 330 are coupled to limestone asset
heating retort injection wells 338 to deliver molten salt 336 for
the retort of the fractured limestone formations. It is envisioned
that system 20 may include various pump configurations including
multiple pumps to maximize the effectiveness of the retort
operation. It is further envisioned that pumps 331 may be employed
to recover residual molten salt, after retort operations, for
return to molten salt generator 328, as part of the recovery and
recycling system of retort system 320 discussed below.
[0075] Limestone asset heating retort injection wells 338 are
installed with the infrastructure of system 20, as discussed.
Molten salt 336 is transferred to injection wells 338 and injected
into the fractured limestone formation. The use of horizontal
drilling described with regard to FIG. 3, can be employed to
maximize the limestone formation exposure to heat necessary to form
both gaseous and liquefied hydrocarbons. It may take between 2-4
years for the formation of sufficient kerogen to be commercially
recoverable. After that recovery may occur on a commercial level
for between 3-30 years or more.
[0076] A product recovery system 360 is constructed at site 22.
Product recovery system 360 may be coupled with injection wells 338
for collection of gaseous and liquefied hydrocarbons that are
released during the retort process or may be perforation recovery
wells. An illustration of the energy flow of system 20 with retort
system 320 (FIG. 8) for limestone retorting operations, as shown in
FIG. 9, includes nuclear energy 346 generated from nuclear reactor
26. Salt is delivered from salt injection system 334 to molten salt
generator 328.
[0077] Nuclear energy 346 creates thermal energy 332 that is
transferred to molten salt generator 328 for producing molten salt
336. Molten salt 336 is delivered to pumps 330 and pump energy 348
delivers molten salt 336 to retort injection wells 338 with
sufficient energy 350 to transfer molten salt 336 to the fractured
limestone formations for heat inducement. The exposure of the
limestone to heat accelerates the maturation of the hydrocarbon
precursors, such as kerogen, which forms liquefied and gaseous
hydrocarbons. During the retort operations, hydrocarbon products
362 accumulate. Hydrocarbon products 362 are extracted and
collected by product recovery system 360. Residual molten salt 364
from the retorting operations are recovered via a salt recovery
system 345 and reinjected to molten salt generator 328 via pumps
331 and salt injection system 334. It is envisioned that salt
recovery system 345 is employed to minimize the consumption of salt
used to retort the fractured limestone formation. Alternatively,
retort system 320, product recovery system 360 and related
components may be employed with limestone and oil shale formation
applications, or only oil shale.
[0078] In another alternate embodiment, as shown in FIG. 10, system
20 includes a retort system 420 for retort operations relating to
the fractured limestone formations at site 22, similar to those
described. Site 22 is prepared for installation and related
construction of retort system 420, which includes a steam
generator, oscillators and thermal transfer system components, as
will be described.
[0079] Retort system 420 employs heat generated by oscillators,
which are mounted with the fractured limestone formations of site
22. The heat generated induces heating of the fractured limestone
formations to accelerate the maturation process of hydrogen
precursors, as discussed. Nuclear reactor 26 discussed above, is a
thermal source that cooperates with a steam generator 228 to power
a steam turbine 230 for generating the electric energy to retort
the fractured limestone formation in-situ. Nuclear reactor 26 is
sized to be located at or near site 22 of the fractured limestone
formation. It is envisioned that the electric capacity rating of
nuclear reactor 26 is between 50 MWe to 3000 MWe. It is
contemplated that the hydrogen generated by nuclear reactor 26 can
be used to enhance the value of carbon bearing material, which may
resemble char, so it will be recoverable. A hydrogen generator (not
shown), either electrolysis, thermal or other may be attached to
the nuclear reactor 26 to generate hydrogen for this use.
[0080] Water supply 34 delivers water to steam generator 228, which
is constructed and installed at site 22. Nuclear reactor 26 is
coupled to steam generator 228, in a manner as is known to one
skilled in the art, for the transfer of thermal energy 232. System
20 employs steam generator 228, in cooperation with nuclear reactor
26 as the thermal source, to produce steam 236 to activate steam
turbine 230 for retort of the fractured limestone formations.
[0081] Steam generator 228 is coupled to steam turbine 230, in a
manner as is known to one skilled in the art. Steam 236 from steam
generator 228 flows into steam turbine 230 to provide mechanical
energy 237 to an electric generator 234. Steam turbine 230 is
coupled to electric generator 234, and mechanical energy 237
generates current 239 from electric generator 234. It is
contemplated that current 239 may include alternating current or
direct current.
[0082] Current 239 from electric generator 234 is delivered to
oscillators 438. The electric power delivered to oscillators 438
via current 239 creates a radio frequency having a wavelength where
the attenuation is compatible with the well spacing to provide
substantially uniform heat.
[0083] A product recovery system 460 is constructed at site 22.
Product recovery system 460 is connected with the recovery wells
for collection of gaseous and liquefied hydrocarbons that are
released during the retort process. An illustration of the energy
flow of system 20 with retort system 420 (FIG. 10) for limestone
retorting operations, as shown in FIG. 11, includes nuclear energy
446 generated from nuclear reactor 26. Nuclear energy 446 creates
thermal energy 232 that is transferred to steam generator 228 for
producing steam. Steam 236 is delivered to steam turbine 230, which
produces mechanical energy 237. Mechanical energy 237 generates
current 239 from electric generator 234.
[0084] Current 239 delivers electric energy to oscillators 438 to
create radio frequencies 241 to heat the fractured limestone
formations for heat inducement. The exposure of the limestone to
heat accelerates the maturation of the hydrocarbon precursors, such
as kerogen, which forms liquefied and gaseous hydrocarbons. During
the retort operations, hydrocarbon products accumulate. The
hydrocarbon products are extracted and collected by product
recovery system 460. Alternatively, retort system 420, product
recovery system 460 and related components may be employed with
limestone and oil shale formation applications, or only oil
shale.
[0085] It will be understood that various modifications may be made
to the embodiments disclosed herein. Therefore, the above
description should not be construed as limiting, but merely as
exemplification of the various embodiments. Those skilled in the
art will envision other modifications within the scope and spirit
of the claims appended hereto.
* * * * *