U.S. patent application number 14/592762 was filed with the patent office on 2015-07-09 for method of recovering hydrocarbons from carbonate and shale formations.
The applicant listed for this patent is Kenneth D. ROGERS, William H. ROGERS. Invention is credited to Kenneth D. ROGERS, William H. ROGERS.
Application Number | 20150192002 14/592762 |
Document ID | / |
Family ID | 53494767 |
Filed Date | 2015-07-09 |
United States Patent
Application |
20150192002 |
Kind Code |
A1 |
ROGERS; William H. ; et
al. |
July 9, 2015 |
METHOD OF RECOVERING HYDROCARBONS FROM CARBONATE AND SHALE
FORMATIONS
Abstract
A method to mobilize for production bitumen, kerogen, heavy oil,
other hydrocarbons, and hydrogen contained in a subterranean
formation comprised largely of silicate and carbonate minerals that
are capable of generating a series of chemical reactions, that once
induced are self-sustaining. Such formations include bitumen
carbonates, unconventional oil or gas shales and oil shales. The
induced silicate-reactions, carbonate-reactions and resulting
hydrocarbon-reactions and heat generated in the formation are
sufficient to chemically and physically decompose much of the rock
structure so that it becomes porous and permeable. These reactions
also convert the solid bitumen, heavy oil, kerogen and other
hydrocarbons to fluid or gaseous forms and create formation fluids
and reservoir pressure to help move hydrocarbons to production
wells. Waste heat generated by the method may be used to generate
electricity, or for other uses.
Inventors: |
ROGERS; William H.; (North
Vancouver, CA) ; ROGERS; Kenneth D.; (Kelowna,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ROGERS; William H.
ROGERS; Kenneth D. |
North Vancouver
Kelowna |
|
CA
CA |
|
|
Family ID: |
53494767 |
Appl. No.: |
14/592762 |
Filed: |
January 8, 2015 |
Current U.S.
Class: |
166/272.2 ;
166/272.1; 166/272.4; 166/272.7 |
Current CPC
Class: |
E21B 43/305 20130101;
Y02P 90/70 20151101; Y02C 20/40 20200801; E21B 43/34 20130101; E21B
43/26 20130101; E21B 43/24 20130101; E21B 41/0064 20130101; Y02C
10/14 20130101; E21B 43/164 20130101 |
International
Class: |
E21B 43/16 20060101
E21B043/16; E21B 43/243 20060101 E21B043/243; E21B 41/00 20060101
E21B041/00; E21B 43/34 20060101 E21B043/34; E21B 43/26 20060101
E21B043/26; E21B 43/24 20060101 E21B043/24; E21B 36/00 20060101
E21B036/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 9, 2014 |
CA |
2839136 |
Claims
1. A method of mobilizing and recovering hydrocarbons from a
subterranean formation comprising hydrocarbons, silicate minerals
and carbonate minerals, comprising the steps of: (a) providing an
injection well and a production well extending into the formation;
(b) injecting carbon dioxide and heat under pressure through the
injection well into the formation sufficient to cause (i) chemical
reactions whereby carbon dioxide decomposes silicate minerals,
producing heat, (ii) chemical reactions whereby heat decomposes
carbonate minerals, producing carbon dioxide, and (iii) heating of
hydrocarbons, giving them greater fluidity; (c) allowing the
effects (i), (ii) and (iii) of step (b) to spread into the
formation around the injection location and decompose silicate
minerals and carbonate minerals in the formation creating in those
areas a more permeable structure and hydrocarbons with greater
fluidity; (d) ceasing the injection of heat and carbon dioxide into
the formation when the effects (i), (ii) and (iii) of step (b) have
spread into the formation and the chemical reactions that decompose
the silicate minerals and the carbonate minerals become
self-sustaining; and (e) recovering resulting formation fluids
comprising fluid and gaseous hydrocarbons from the production
well.
2. A method according to claim 1, wherein, in step (b), the step of
injecting heat through the injection well comprises heating a fluid
or gas and injecting the hot fluid or gas through the injection
well.
3. A method according to claim 2, wherein the hot fluid comprises
carbon dioxide.
4. A method according to claim 1, wherein, in step (b), the step of
injecting heat through the injection well comprises injecting a
combustible fuel through the injection well and igniting the
combustible fuel.
5. A method according to claim 1, wherein, in step (b), the step of
injecting heat through the injection well comprises injecting a
fluid or gas down the injection well through or close by a down
hole heater.
6. A method according to claim 1, further comprising, in step (b),
injecting steam into the formation materials.
7. A method according to claim 1, further comprising extracting
heat from the formation and delivering it to the ground
surface.
8. A method according to claim 7, wherein said step of extracting
heat from the formation is continued after ceasing step (e).
9. A method according to claim 1, further comprising providing a
heat energy extraction system having a wellbore extending into the
formation, and extracting heat energy from the formation using the
heat energy extraction system.
10. A method according to claim 1, further comprising recovering
produced fluid or gaseous hydrocarbons from the injection well.
11. A method according to claim 1, further comprising recovering
heat energy from the produced formation fluids.
12. A method according to claim 1, wherein the produced formation
fluids further comprise carbon dioxide, and the method further
comprising separating and compressing the carbon dioxide.
13. A method according to claim 12, further comprising sequestering
the separated carbon dioxide.
14. A method according to claim 1, wherein the produced formation
fluids further comprise greenhouse gases other than carbon dioxide,
and the method further comprises separating, compressing and
sequestering said greenhouse gases.
15. A method according to claim 1, wherein a portion of the
formation contains insufficient carbonate minerals for the chemical
reactions that decompose the silicate minerals to be
self-sustaining throughout the formation, and the method further
comprises using the existing injection well, or providing a second
injection well into that portion of the formation, and injecting
carbon dioxide under pressure into that portion of the formation,
continuing to do so until sufficient carbonate minerals are
available such that the chemical reactions that decompose the
silicate minerals and the carbonate minerals become
self-sustaining.
16. A method according to claim 1, wherein a portion of the
formation contains insufficient silicate minerals for the chemical
reactions that decompose the carbonate minerals to be
self-sustaining throughout the formation, and the method further
comprises using the existing injection well, or providing a second
injection well into that portion of the formation, and injecting
heat under pressure into that portion of the formation, continuing
to do so until sufficient silicate minerals are available such that
the chemical reactions that decompose the silicate minerals and the
carbonate minerals become self-sustaining.
17. A method according to claim 1, further comprising suppressing
the chemical reactions that decompose the carbonate minerals and
the silicate minerals in at least a portion of the formation.
18. A method according to claim 17, wherein the suppressing is done
by means of (i) injecting a gas other than carbon dioxide into the
formation, (ii) injecting a cold liquid into the formation, or
(iii) reducing the pressure in the formation.
19. A method according to claim 1, wherein the production well
includes a generally horizontal portion in the formation
20. A method according to claim 1, wherein the production well
includes a generally vertical portion in the formation.
21. A method of mobilizing and recovering hydrocarbons from a
subterranean formation comprising hydrocarbons, silicate minerals
and carbonate minerals, comprising the steps of: (a) providing an
injection well and a production well extending into the formation;
(b) fracturing a portion of the formation to form a region of
fractured formation materials in fluid communication with the
injection well; (c) injecting carbon dioxide and heat under
pressure through the injection well into the region of fractured
formation materials sufficient to cause (i) chemical reactions
whereby carbon dioxide decomposes silicate minerals, producing
heat, (ii) chemical reactions whereby heat decomposes carbonate
minerals, producing carbon dioxide, and (iii) heating of
hydrocarbons, giving them greater fluidity; (d) allowing the
effects (i), (ii) and (iii) of step (c) to spread into the
formation around the region of fractured formation materials and
decompose silicate minerals and carbonate minerals in the formation
creating in those areas a more permeable structure and hydrocarbons
with greater fluidity; (e) ceasing the injection of heat and carbon
dioxide into the region of fractured formation materials when the
effects (i), (ii) and (iii) of step (c) have spread into the
formation around the region of fractured formation materials and
the chemical reactions that decompose the silicate minerals and the
carbonate minerals become self-sustaining; and (f) recovering
resulting formation fluids comprising fluid and gaseous
hydrocarbons from the production well.
22. A method according to claim 21, wherein, in step (c), the step
of injecting heat through the injection well comprises heating a
fluid or gas and injecting the hot fluid or gas through the
injection well.
23. A method according to claim 22, wherein the hot fluid comprises
carbon dioxide.
24. A method according to claim 21, wherein, in step (c), the step
of injecting heat through the injection well comprises injecting a
combustible fuel through the injection well and igniting the
combustible fuel.
25. A method according to claim 21 wherein, in step (c), the step
of injecting heat through the injection well comprises injecting a
fluid or gas down the injection well through or close by a down
hole heater.
26. A method according to claim 21 further comprising, in step (c),
injecting steam into the region of fractured formation
materials.
27. A method according to claim 21, further comprising, in step
(b), fracturing a portion of the formation to form a region of
fractured formation materials in fluid communication with the
production well.
28. A method according to claim 21, further comprising, in step
(b), fracturing a portion of the formation to form a region of
fractured formation materials in fluid communication with both the
injection well and the production well.
29. A method according to claim 21, further comprising extracting
heat from the formation and delivering it to the ground
surface.
30. A method according to claim 29, wherein said step of extracting
heat from the formation is continued after ceasing step (f).
31. A method according to claim 21, further comprising providing a
heat energy extraction system having a wellbore extending into the
formation, and extracting heat energy from the formation using the
heat energy extraction system.
32. A method according to claim 21, further comprising recovering
produced fluid hydrocarbons from the injection well.
33. A method according to claim 21, further comprising recovering
heat energy from the produced formation fluids.
34. A method according to claim 21, wherein the produced formation
fluids further comprise carbon dioxide, and the method further
comprising separating and compressing the carbon dioxide.
35. A method according to claim 34, further comprising sequestering
the separated carbon dioxide.
36. A method according to claim 21, wherein the produced formation
fluids further comprise greenhouse gases other than carbon dioxide,
and the method further comprises separating, compressing and
sequestering said greenhouse gases.
37. A method according to claim 21, wherein a portion of the
formation contains insufficient carbonate minerals for the chemical
reactions that decompose the carbonate minerals to be
self-sustaining throughout the formation, and the method further
comprises providing a second injection well and injecting carbon
dioxide under pressure through the second injection well into the
formation.
38. A method according to claim 21, wherein a portion of the
formation contains insufficient silicate minerals for the chemical
reactions that decompose the silicate minerals to be
self-sustaining throughout the formation, and the method further
comprises providing a second injection well and injecting heat
through the second injection well into the formation.
39. A method according to claim 21, further comprising suppressing
the chemical reactions that decompose the carbonate minerals and
the silicate minerals in at least a portion of the formation.
40. A method according to claim 39, wherein the suppressing is done
by means of (i) injecting a gas other than carbon dioxide into the
formation, (ii) injecting a cold liquid into the formation, or
(iii) reducing the pressure in the formation.
41. A method according to claim 21, wherein the production well
includes a generally horizontal portion in the formation.
42. A method according to claim 21, wherein the production well
includes a generally vertical portion in the formation.
43. A method according to claim 21, wherein the hydrocarbons
comprise heavy hydrocarbons.
44. A method according to claim 1, wherein the hydrocarbons
comprise kerogen.
45. A method according to claim 1, wherein the injection well and
the production well are one and the same well, extending into the
formation.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to methods and systems to
mobilize and produce hydrocarbons and related by-products from
various sub-surface formations, including in particular,
hydrocarbon-bearing impermeable carbonate and shale formations.
BACKGROUND OF THE INVENTION
[0002] New sources of conventional oil reserves have been
significantly declining for several decades while the demand for
energy has continued to grow. Conventional deposits of gas and oil
in North America have essentially been found and largely depleted.
The increasing demand in North America has been generally met by a
combination of unconventional oil and gas production and oil sands
production.
[0003] The unconventional, oil sands and bitumen carbonate
hydrocarbons are much more difficult and expensive to produce.
Mineable oil sands production is well known and successful, but
environmentally is a problem. Deeper oil sands are currently being
produced with SAGD and/or solvent methods. Bitumen carbonates,
located in the center of oil sands area of Alberta, are huge, solid
and impermeable deposits, and have no known economic method of
production. Oil shales, such as the Green River formation comprise
solid kerogens and likewise have no known economic method of
extraction. Unconventional formations are common and comprise shale
and siltstone rock hosting free oil and/or gas that may or may not
originate from the same shale formation. The primary known method
of producing economic amounts from tight unconventional formations
is by drilling long horizontal production wells and fracturing the
surrounding rock.
[0004] The recovery methods available to date have been
unsuccessful in economically recovering hydrocarbons from the vast
amounts of heavy hydrocarbons contained in solid impermeable
carbonate rock formations such as the Grosmont carbonates and other
bitumen carbonates of northern Alberta and the Green River
formation oil shales and other unconventional oil shales. The
recovery rates for light and medium weight unconventional oils are
generally reported to be between 10 and 30 percent, even after
enhanced recovery methods. The recovery methods for unconventional
natural gas from the Montney, Horn River and Liard formations and
other unconventional reservoirs are estimated by Canada's National
Energy Board to be able to recover about 15 to 20 percent of the
total estimated gas.
[0005] The current art for the recovery of heavy hydrocarbons from
solid impermeable subterranean formations is largely based on
methods currently being used to enable economic recovery of bitumen
from the Alberta oil sands, and heavy oils in Alberta and
Saskatchewan. These methods are generally relatively expensive and
are environmentally poor. The methods used in non-mining situations
are some variation of the following: [0006] Steam Assisted Gravity
Drainage (SAGD) and Cyclical Steam Stimulation (CCS) both of which
use large amounts of natural gas to create steam to mobilize
bitumen, and produce a fluid mixture of hot bitumen and substantial
polluted water; [0007] Heat Assisted Gravity Drainage (HAGD), and
Thermal Assisted Gravity Drainage (TAGD), which use heat from down
hole electric heaters or other similar means to mobilize bitumen,
and produces a mixture of hot bitumen and some polluted water;
[0008] Vapor Extraction (VAPEX), and other solvent-based methods
use diluents to mobilize the bitumen and produce a slurry of cool
bitumen, diluent and some polluted water.
[0009] The above basic recovery methods can be combined in numerous
ways and various supplementary processes or substances may be added
to these basic processes with the objective of improving the
recovery, improving the economics, achieving some in situ upgrading
of the bitumen or reducing the pollution or rectifying other
problems with the basic recovery methods. Fire flooding or in situ
combustion systems, such as toe to heel air injection (THAI), have
also been attempted, but with limited success.
[0010] All of the three initial basic methods have several major
economic and environmental drawbacks: a) large amounts of injected
energy is required to power the process, which is expensive; b)
large amounts of scarce water is used and polluted; and c) large
quantities of greenhouse gases are generated and released to the
atmosphere. For unconventional oil or gas production extensive
hydraulic fracturing is required, which is expensive and generally
has similar or worse environmental problems.
[0011] All known methods for in situ mobilizing of hydrocarbons in
a bitumen carbonate formation, as well as in all other heavy oil
and deeper oil sands formations, have the fundamental requirement
that heat or diluents must be applied into the formation from the
surface, essentially continuously. The mobilizing process usually
takes the form of some variation of steam or diluent injection or
some form of electronic or gas heaters being placed in the
formation.
[0012] Electric heaters, SAGD, HAGD, CSS and combinations thereof
and VAPEX involve the continuous or near-continuous injection of
large quantities of energy or fuel from the surface in the attempt
to mobilize at least some kerogen, bitumen or heavy oil in the
formations. The cost to continuously do this is the major reason
these processes are so expensive. The process of generating the
heat or the solvents required is also one of the primary sources of
greenhouse gas emissions to the atmosphere.
[0013] Bitumen carbonates (and oil or gas shales or siltstones) are
very solid and very impervious rock formations. Heating the
formation to typical SAGD/CSS temperatures of less than 400.degree.
C. will not make a significant change to these two characteristics.
The formations are very solid and generally nothing will flow
through them. This means injecting concoctions of fluids will
likely also have little effect, as they will generally not
penetrate the formation significantly. Injected heat and injected
concoctions of chemicals are the essence of all the current bitumen
carbonate processes. If they work at all it appears they may be
only marginally economic.
[0014] All current processes relating to bitumen carbonates are
generally focused on the fact that sufficiently heated bitumen will
flow. It will, however, only flow if it has an exit path to follow.
In their natural state bitumen carbonate and shale formations have
few if any such paths. The formation rock structure, including the
bitumen, is generally solid and impermeable.
[0015] To successfully produce a much greater percentage of
contained hydrocarbons from bitumen carbonates it appears that the
processes must be focused on attacking and modifying at least some
of the rock structure throughout the formation. Then, immediately
adjacent released hydrocarbons should find an exit path and be
mobilized towards production wells. Talley, U.S. Pat. No.
5,255,740, discloses a process that can theoretically recover some
hydrocarbons from impermeable carbonate formations by injecting
heat into the formation at temperatures that are high enough to
decompose some of the immediate carbonate minerals contacted by the
heat and make some of it more permeable. A hot fluid, usually
steam, is used to deliver the heat to the rock structure, or a
solvent is delivered which causes heat. The decomposition of some
of the carbonate minerals is endothermic and cooling takes place.
To attack and decompose more of the carbonate minerals to extend
the improvement in permeability requires more very expensive
on-going injections of heat and/or solvents Like the bitumen
carbonates, the oil shales are definitely less receptive to the
methods that have been considered successful in oil sands
production.
[0016] Shale gas and shale oil are found in sedimentary shale rocks
(including siltstone) that are rich in organic material and which
are usually both the source rock and the reservoir or trap for the
natural gas or oil. The natural gas or oil found in these rocks is
referred to as unconventional. They are stored in the host rock in
three ways: (i) adsorbed onto insoluble organic matter generally
referred to as kerogen, that forms a molecular or atomic film; (ii)
free gas trapped in the extremely small pore spaces of the fine
grained sediments interbedded with the rock much like conventional
reservoirs; and (iii) confined in fractures within the shale
itself. Gas is also often held within other liquids such as bitumen
and oil. These are often referred to as oil-bearing or gas-bearing
shales.
[0017] With the developments of horizontal drilling, multistage
hydraulic fracturing and pad drilling, massive shale formations
such as the Bakken for oil and the Montney, Liard and Horn River
for natural gas, have become very prolific producing areas. These
production methods for oil and gas shales have changed the supply
situation in North America. They have also created a number of
problems, such as immense fresh water usage and resulting
contaminations. Unconventional wells have very rapid decline rates
and are very expensive. Only a relatively small portion of the
contained hydrocarbons in these shales is currently extractable,
estimated by Canada's National Energy Board to be between 10 and 20
percent for natural gas.
[0018] With oil or gas-bearing shale formations, the only
successful extraction method to date has been a direct attack on
the formation, by fracturing parts of the formation. The reach of
the fracturing generally does not interconnect with other applied
fractures; such that in some formations the number of wells per
section has been doubled and there is still little or no
interconnecting of fractures. Fracturing is a very expensive
process that extracts a relatively small percentage of the
hydrocarbons in place. It also has been strongly criticized for its
built-in greenhouse gas and other negative environmental
impacts.
[0019] Oil shales differ from oil-bearing unconventional shales
which contain petroleum or gas. Oil shale is an organic-rich, fine
grained sedimentary rock that contains essentially only kerogen.
Kerogen is a solid mixture of organic chemical compounds from which
liquid hydrocarbons referred to as shale oil can be produced. This
process requires high temperatures to cause the chemical process of
pyrolysis to yield a vapor, which on cooling produces a liquid
shale oil. Kerogens are an early stage in the creation of petroleum
through heat and pressure. To date there is no reported means of
economically extracting hydrocarbons from these kerogen deposits.
The known art includes a process that injects heat into a
subterranean oil shale formation at a high enough temperature to
decompose some of the rock (Papadopoulos et al., U.S. Pat. No.
3,741,306). However, as is the case for the Talley process for
carbonates, this process is essentially theoretical because heat
must be injected continuously, thus making any in situ process
prohibitively expensive. There are currently no economic extraction
solutions for the massive oil shale deposits, such as the Green
River formation in Colorado, Utah, and Wyoming.
[0020] It would be a major advance in bitumen carbonate and oil
shale production if methods of recovery did not require immense
on-going injections of heat energy or equivalent. It would be a
major improvement in the development of tight oil or gas formations
if there were a cheaper and more effective means of attacking the
structure such that far more of the contained hydrocarbons may
ultimately be recovered. It would be a major environmental advance
if production of hydrocarbons could be accomplished with the
essential elimination of CO.sub.2 or other greenhouse gases being
released to the atmosphere. It would be a major environmental
advance if production methods used little or no water. It would
make economic and environmental sense if significant waste heat
generated from any production process could be used productively
and economically.
SUMMARY OF THE INVENTION
[0021] The invention is a method to mobilize and recover
hydrocarbons from impermeable subterranean hydrocarbon formations
comprised largely of mixed silicate and carbonate minerals. The
method is to induce within the formation a series of complementary
and self-sustaining chemical reactions which attack and decompose
much of the impermeable solid rock structure, thereby making it
more porous and permeable. At the same time the reactions generate
considerable heat, pressure and formation fluids, and thereby
provide the fluidity and mobility needed for hydrocarbon recovery.
An injection well and a production well, or a combined
injection/production well, are provided extending into the
formation. Heat and carbon dioxide are injected under pressure
through the injection well into the formation materials, sufficient
to cause (i) chemical reactions that decompose silicate minerals,
thereby producing heat, (ii) chemical reactions that decompose
carbonate minerals, thereby producing carbon dioxide, and (iii)
heating of hydrocarbons, which creates additional chemical
reactions plus fluidity of hydrocarbons. Mobilized hydrocarbons
plus CO.sub.2, H.sub.2, and O.sub.2 and pressure, create aggressive
formation fluids which move through the decomposed material toward
the production well. The pressured injection of heat and carbon
dioxide into the formation materials is ceased when the three
effects of the continuous injection have taken hold in the
formation and the chemical reactions that decompose the silicate
and carbonate minerals become self-sustaining.
[0022] Resulting formation fluids, including mobilized
hydrocarbons, move through the decomposed structure primarily
driven by pressure differential and gravity, and are recovered by
way of the production well. In another embodiment, formation
material immediately adjacent to the injection well is fractured
prior to injections to allow the induced reactions to take place
quicker and more assuredly. In yet another embodiment, formation
material is fractured adjacent to the injection well and to the
production well to ensure there is a ready path to the production
well. There are many benefits arising from the use of the
invention, the two most significant being: (i) reduction of the
costs for on-going heat injections during operations, and (ii)
increase in the over-all recovery of hydrocarbons in place.
[0023] Further aspects of the invention and features of specific
embodiments are described below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a schematic, viewed from above, of an embodiment
of layouts of the multi-well pad, injection wells, production wells
and heat recovery wells for treating a hydrocarbon-containing
formation comprised mainly of silicate and carbonate minerals.
[0025] FIG. 2 is a schematic, viewed as an elevation, of an
embodiment of layouts of the multi-well pad, injection wells,
production wells and heat recovery wells for treating a
hydrocarbon-containing formation comprised mainly of silicate and
carbonate minerals.
[0026] FIG. 3 is a schematic representation of a flow process for
using the method of the invention in a subterranean formation
comprised primarily of silicate and carbonate minerals to mobilize
and produce hydrocarbons.
[0027] FIG. 4 depicts a schematic representation of the heat
recovery process or the flow process to deliver waste heat or some
of the induced heat from the subterranean formation to the surface
to generate electricity, or for another use of heat.
DETAILED DESCRIPTION
[0028] The method of the invention is based on three sets of
chemical reactions occurring in situ in a subterranean formation
comprised, in significant part, of silicate minerals, carbonate
minerals and hydrocarbons. The reactions must be induced, but once
induced the chemical reactions are complementary and
self-sustaining. The method of the invention is referred to herein
as the "Induced Reactions process", and the reactions are referred
to as the "induced-reactions" while they are occurring in the
formation because of injections from the surface.
[0029] Once the three sets of in situ chemical reactions are
self-sustaining in a formation with a mix of minerals appropriate
for the Induced Reactions process, they collectively create all, or
virtually all of, the permeability, heat, formation fluids and
pressure necessary to mobilize hydrocarbons and drive the
hydrocarbons to lower pressure production wells.
[0030] The chemistry of each of the induced-reactions is well
known.
[0031] Silicate-Reactions
[0032] The first set of induced reactions is a species of
weathering. Each metal mineral, such as mudstone (an aluminum
silicate), has an enthalpy or an amount of energy as a
thermodynamic system. When the chemical bonds of the mineral are
broken by weathering, some of the enthalpy, in the form of heat, is
released to the immediate environment. At normal surface
temperatures and pressure this occurs extremely slowly, and is
essentially imperceptible. Tuval et al., U.S. Pat. No. 4,491,367,
delineates the use of this exothermic chemical reaction to generate
substantial subterranean heat. The weathering process, being the
decomposition of the silicate minerals, can be artificially
accelerated in a contained subterranean formation of the required
composition and pressure by an order of 10.sup.7 to 10.sup.8 with
the generation of large amounts of heat. This process, if 10.sup.7,
would essentially mean that the induced chemical reactions in the
subterranean formation will decompose rock in one day that would
take 10 million days or over 27,000 years of surface weathering to
be similarly decomposed, an immense acceleration.
[0033] The types of formations needed to utilize this acceleration,
require silicate minerals corresponding to the general formula:
aM.sub.x.sup.1O.sub.rbM.sub.z.sup.2O.sub.ycSiO.sub.2.dH.sub.2O
where M.sup.1 and M.sup.2 each stand for a metal, each of a, b, c,
d, x, y, z, is an integer of 1 to 10 and any one of a, b and d may
also be zero.
[0034] The preferred silicate minerals are aluminosilicates, such
as most clays and feldspars, corresponding to the general
formula:
aM.sub.2.sup.3O.Al.sub.2O.sub.3cSiO.sub.2.dH.sub.2O
where a and c are as in the general formula and M.sup.3 is a
monovalent metal and d is an integer from 1 to 10.
[0035] The accelerated weathering of an aluminosilicates comprises
two parts:
dM.sub.2O.Al.sub.2O.sub.3cSiO.sub.2.dH.sub.2O+dCO.sub.2.fwdarw.dMCO.sub.-
3+H.sub.4Al.sub.2Si.sub.2O.sub.9+4SiO.sub.2+HEAT
and, because the H.sub.4Al.sub.2Si.sub.2O.sub.9 is unstable:
H.sub.4Al.sub.2Si.sub.2O.sub.9.fwdarw.2H.sub.2+O.sub.2+Al.sub.2O.sub.3+S-
iO.sub.2
[0036] (This first group of reactions is referred to herein as
"silicate-reactions")
[0037] The silicate-reactions occur in situ and use CO.sub.2 to
transform silicate minerals in a relatively solid and impermeable
formation rock structure into a more porous and permeable
structure, plus generate heat, formation fluids (comprised
primarily of free hydrogen (H.sub.2), free oxygen (O.sub.2)), and
additional reservoir pressure.
[0038] Carbonate--Reactions
[0039] It is well known that heating a solid piece calcium
carbonate rock (limestone) in a test tube results in a white powder
(lime) and a gas (CO.sub.2).
CaCO.sub.3+heat CaO+CO.sub.2
[0040] The chemical bonds of dolomite, (CaMg) (CO.sub.3).sub.2, a
major component of the formation rock of the Grosmont carbonates
formation, can similarly be decomposed into CO.sub.2 and a more
porous residual substance replacing the original carbonate
mineral.
[0041] (This second group of reactions is referred to herein as
"carbonate-reactions").
[0042] The carbonate-reactions occur in situ and use heat to
transform carbonate minerals in a relatively solid and impermeable
formation rock structure into a more porous and permeable
structure, CO.sub.2, and additional reservoir pressure.
[0043] Complementary and Self-Sustaining Reactions
[0044] The silicate-reactions and the carbonate-reactions are
complementary and supportive while reacting within the formation.
The silicate-reactions generate the heat necessary to keep the
carbonate-reactions going, which in turn provide the CO.sub.2
necessary to keep silicate-reactions going. In the right balance of
silicates and carbonates this is a self-sustaining process. It is
expected that a large number of hydrocarbon formations will fit the
requirements as silicates and carbonates are abundant and are
common together.
[0045] Once induced and sustained, the carbonate-reactions and the
silicate-reactions in the subterranean formation continue to
decompose or break the chemical bonds of the silicate and carbonate
minerals which comprise the majority of the rock structure of a
formation suitable for the present invention.
[0046] Hydrocarbon-reactions, discussed below, start to occur once
the hydrocarbons are exposed to the heat and other products of the
silicate-reactions and the carbonate-reactions, after which they
contribute to creating pathways to enable the silicate-reactions
and carbonate-reactions to spread throughout the formation and
eventually decompose much of the rock structure.
[0047] Because the induced-reactions will so significantly
transform the formation rock structure, once they become
self-sustaining and expand beyond the region where the reactions
are induced, they are referred to collectively as
"structure-changing-reactions".
[0048] The transformations of the silicate and carbonate minerals
and the hydrocarbons, as the structure-changing-reactions spread
through the formation, is relatively slow and has an effect like a
very slow moving continuous fracturing of the formation.
[0049] Each of the silicate, carbonate and hydrocarbon chemical
reactions has a role in: a) breaking down the rock structure, which
increases the permeability in general and exposes the hydrocarbons
in particular, b) creating formation fluids, c) increasing the
pressure, and d) creating sufficient heat to liquefy the exposed
hydrocarbons which mobilizes them to flow with the other formation
fluids through the more permeable parts of the rock formation to
lower pressure production wells.
[0050] Inducing the Reactions
[0051] The silicate-reactions and carbonate-reactions cannot be
started easily, especially in a solid and impermeable rock
structure. They must be artificially started or "induced". The
silicate-reactions normally need continuous CO.sub.2 to occur and
the carbonate-reactions normally need continuous heat to occur.
[0052] The essence of the inducement procedure is to inject
whatever is needed into the region near the bottom of each
injection well of each unique reservoir to cause the reactions to
occur until both: (a) the silicate-reactions are on-going using
CO.sub.2 generated in situ from the carbonate reactions and (b) the
carbonate-reactions are on-going using heat generated in situ from
the carbonate reactions. The region near the bottom of each
injection well where the reactions are to be induced is referred to
as an "inducement pocket".
[0053] As part of the inducement stage only, target formations
could possibly require the injection of only one of either heat or
CO.sub.2 into the inducement pocket via the injection well. In most
cases the inducement will require, or be more easily achieved, with
the injection of both heat and CO.sub.2 into the inducement pocket.
Other procedures that may be required or useful to kick-start the
self-sustaining reactions in a particular formation include
increasing pressure in the inducement pocket and fracturing the
region near the bottom of each injection well to help create a more
permeable inducement pocket. For better control of the process the
inducement pocket fracturing may be extended to where fluid
communication with the production well is created. For most solid
and impermeable formations, all four procedures, injecting
CO.sub.2, heat and pressure and some fracturing will probably be
required. All four procedures are known art. The injections must be
applied through the injection well until the reactions are induced
and then sustained in the unfractured formation.
[0054] Injected CO.sub.2 passing through or near a down-hole
electric heater, as an example, may be sufficient to start the
reactive process. There are many known means of heating such a
small area. Heating could be done prior to the injection of
CO.sub.2. Such heating means may include injected steam or
combustible fuel, both of which are well known in the art.
[0055] Depending on the water content of the formation, some
injected steam may also be required as part of the inducement
process. Once the silicate-reactions and carbonate-reactions become
self-sustaining, all inducement injections of heat, CO.sub.2 and
H.sub.2O would normally cease. Except for the possibility of
supplemental injection of CO.sub.2 or heat if either silicate or
carbonate minerals are inadequate in a portion of the formation,
the injection well would subsequently have little purpose as such.
It may be utilized as a conduit for monitoring purposes. In some
situations it may be used as a production well
[0056] When the formation is thick, minor vertical fracturing of
the formation adjacent to each injection well may assist to
establish early exit paths to production wells. This would enable
the early recovery of most quality medium hydrocarbons before
higher temperatures change them. The recovery of progressively
heavier hydrocarbons proceeds as the temperatures slowly increase
through the on-going decomposition of the adjacent silicate
minerals.
[0057] Hydrocarbon-Reactions
[0058] Herein, "hydrocarbons" refers to any compound comprised
primarily of carbon and hydrogen, including heavy hydrocarbons and
accompanying elements, including but not limited to halogen
elements, metallic elements, nitrogen, oxygen and sulfur; and
"heavy hydrocarbons" refers to kerogen, bitumen, heavy oil, tar,
asphalt, coal, oil shale, natural mineral waxes and asphaltenes, as
well as any accompanying smaller concentrations of sulfur, oxygen,
nitrogen, and other elements in trace amounts.
[0059] The silicate-reactions and carbonate-reactions gradually
breakdown the rock structure such that previously encapsulated
hydrocarbons are exposed to sufficient of the heat, created by the
silicate-reactions, that the hydrocarbons are progressively
converted to fluid form. The hydrocarbons are also exposed to, and
start to chemically react with, the formation fluids and other
products of the decomposition.
[0060] The hydrocarbons, including related elements, especially
sulfur and nitrogen, become an integral part of the series of
chemical reactions that physically and chemically change the rock
structure and otherwise help mobilize the hydrocarbons for
production.
[0061] All petroleum products, including bitumen, heavy oil and
other heavy hydrocarbons usually contain small amounts of
non-hydrocarbon organic compounds containing sulfur, nitrogen and
oxygen, and they also contain small amounts of metals, usually
copper, iron, nickel and vanadium. As the solid heavy hydrocarbon
component of the rock structure starts to break down into its new
components, many of the resulting minerals and other substances
will participate in chemical reactions with each other and with the
substances created by decomposition of the silicate and carbonate
minerals. The possible reactions are numerous and the reactions in
each formation will vary with the unique makeup of the respective
rock structures. Some reactions will improve permeability and the
mobilization and recovery of hydrocarbons, and some may tend to
hinder these targeted changes. These hydrocarbon reactions help
create exit pathways from inducement-pockets to production
wells.
[0062] Some of the hydrocarbon substances combine to form strong
acids such as nitric acid (HNO.sub.3) and sulfuric acid
(H.sub.2SO.sub.4) as well as weak acids and bicarbonate
(HCO.sub.3). Some of the heavy hydrocarbons may be dissolved in
available carbon dioxide (CO.sub.2) or water. If a silicate mineral
is hydrous, a significant amount of extremely hot water may be
created. The strong acids in particular will cause reactions that
contribute to the transformation of the resident rock and/or add
heat.
[0063] The heat from the silicate-reactions ultimately causes some
thermal cracking of some of the hydrocarbons. Some catalytic
cracking may occur, particularly because a significant amount of
hydrogen is created by the silicate-reactions. Some in situ
refining occurs.
[0064] Increased pressure contributes significantly to the mobility
of hydrocarbon-bearing formation fluids, especially gases.
Increased pressure also helps move hot gases through the formation
in front of the main heat-generating chemical reactions. The gases
and other formation fluids are inclined to move toward lower
pressure spaces and attack the adjacent rock while doing so. The
pressure and chemical reactions help create exits from the
inducement pocket and new small spaces referred to as
"gas-pockets", to which these hot formation fluids can flow and
eventually to production wells.
[0065] The chemical reactions arising between the hydrocarbon
components and the products of the decomposing rock structure are
referred to herein as "hydrocarbon-reactions".
[0066] In summary, the features of the Induced Reactions process
include: chemically decomposing the rock structure to create all of
the required heat, permeability, pressure and formation fluids in
situ, rather than from the surface; the inducement of this as a
complementary, self-sustaining process to mobilize and produce
hydrocarbons; the partial refining of the hydrocarbons in situ, the
creation of considerable extra heat and free hydrogen as valuable
by-products; and the lack of inherent environmental problems.
[0067] The Induced Reactions process is a genuine in situ process.
After inducement, all heat required to mobilize and produce
hydrocarbons by way of the silicate-reactions part of the process
is generated in situ. This eliminates the large on-going cost
required of all existing processes of continually injecting heat
and/or solvents from the surface, or of fracturing and
re-fracturing the formation.
[0068] More heat will be generated than is needed to decompose the
carbonate minerals and convert the hydrocarbons to fluid form, even
when silicate minerals comprise significantly less of the rock
structure than carbonate minerals. Over time normally so much heat
will be generated that cheap waste heat will be available for use
at the surface using a heat recovery system. One embodiment, shown
in FIG. 3, recovers this abundant extra heat to produce electricity
without generating greenhouse gases, using a method set forth in
Rogers et al, US 2013/0234444, referred to as a "Pipes system" and
a single module in a Pipes system, a "Pipes Circuit".
[0069] The structure-changing-reactions from a modest sized
subterranean silicate/carbonate rock deposit (40 m thick by 10
km.sup.2, or 400,000,000 m.sup.3) could produce enough heat to run
a sizable (approximately 300 MW) electric power plant for 30 years;
assuming enthalpy of 230 Kcal/kg of rock, rock with a bulk density
of 3, operating 7500 hours/year, recovering 40% of the heat to the
surface and plant efficiency of 2700 Kcal/KWh.
[0070] In addition to heat, the in situ Induced Reactions process
also creates all required permeability, reservoir pressure, and
formation fluids necessary to mobilize and produce hydrocarbons.
After the chemical reactions have been induced, injections of heat
and/or solvents, CO.sub.2, pressure, water or other fluids from the
surface will usually not be required, because each round of the
structure-reactions is caused by some of the products of the
previous round. Each new round of structure-reactions generates
additional high temperature heat, additional CO.sub.2, and
additional pressure. They also continually produce additional
formation fluids comprised largely of free hydrogen and free oxygen
and, carrying in solution or in suspension, additional mobilized
kerogen, bitumen, heavy hydrocarbons and other hydrocarbons and
coke.
[0071] The large quantity of the free hydrogen and free oxygen
produced makes these valuable byproducts that can be sold or used
on site. The lesser amounts of other valuable substances, such as
sulfur, that are carried to the surface in the formation fluids can
be accumulated and sold.
[0072] The produced formation fluids will also contain polluted
water and other noxious substances, but far less than processes
like SAGD. CO.sub.2 produced can be re-injected into the formation
to cause additional silicate-reactions. The lesser amounts of
polluted water and other noxious fluids that are produced and that
are not valuable may be processed or stored and subsequently
reinjected into the reservoir for permanent sequestration.
[0073] SAGD processes continuously inject hot water or steam into
the reservoir and this water comprises the majority of the
formation fluids and it is much polluted when it is produced. The
Induced Reactions process essentially does not inject water or
solvents, so it does not have a large scale environmental problem
relating to its use of water. One embodiment, shown in FIG. 3,
re-injects any polluted water or other noxious fluids that may be
produced so no greenhouse gases are released to the atmosphere, no
settling ponds are needed and no release of polluted water into the
environment occurs--making the Induced Reactions process
essentially pollution free.
[0074] The pollution-free dimension of the Induced Reactions
process is very important. The Alberta oilsands is generally
perceived by the public to be an environmental catastrophe. With
use of the Induced Reactions process in the Bitumen Carbonates much
of this image could be changed, and costs of production would be
substantially reduced at the same time.
[0075] In a formation with the required minerals mix the Induced
Reactions process can mobilize and produce a marvelously high
percentage of the bitumen and other hydrocarbons in place. In a
formation, all but the lighter early-produced hydrocarbons will
come in direct contact with the gradually increasing high
temperature heat and abundant free hydrogen. This will cause in
situ thermal cracking and hydrocracking of much of the remaining
hydrocarbons, including solid kerogen, bitumen heavy hydrocarbons
and even coke. One embodiment, shown in FIG. 3, takes the partly
refined bitumen that is produced through an on-site
upgrading/refining facility using the byproducts, hydrogen and
excess heat, to refine the hydrocarbons so they can avoid or reduce
the heavy oil and bitumen price discounts.
[0076] As the process moves through a formation significant
decomposition of the silicate and carbonate minerals will have
taken place, meaning coke, solid heavy ends and other remaining
hydrocarbons are no longer locked in as part of the rock structure.
The exposure to heat and hydrogen will liquefy and upgrade some of
these. Much of the remaining bitumen, coke and other heavy ends
will be carried by the formation fluids, in solution, by suspension
or simply by pressure, to the production wells.
[0077] By doing minor fracturing in certain locations at the
inducement stage, more assured exit paths will be created from the
initial inducement pockets and structure-changing-chambers to
production wells. This will allow earlier production and better
control to be realized. It also allows production without as much
heat being applied to the medium weight hydrocarbons.
[0078] Silicate and carbonate minerals will rarely be distributed
evenly in a formation. In a selected formation, if carbonate
minerals are lacking in some areas of the formation then
supplemental injections of CO.sub.2 into those areas will continue
the structure-reactions until more carbonates are available in the
formation. Similarly, if silicates are lacking in an area then
supplemental heat may be injected to keep the structure-reactions
process advancing until more silicates are generally available in
the formation.
[0079] A primary target of the Induced Reactions process is
mobilizing and producing bitumen, kerogen and related hydrocarbons
from solid impermeable formations such as the Grosmont carbonates
and the Green River formations. The Induced Reactions process may
also be used to mobilize and recover hydrocarbons from other
subterranean hydrocarbon-bearing formations that also comprise a
combination of silicate and carbonate minerals capable of
supporting accelerated decomposition. These others include, but are
not limited to, tight oil shales such as the Bakken formation,
tight natural gas shales such as the Montney, Horn River and Liard
formations in North East British Columbia, produced reservoirs that
have remaining hydrocarbons for which other recovery methods may be
less economic and possibly some oilsands formations.
[0080] Unconventional formations in which fracturing methods have
previously been applied are a target, because a very high
percentage of original hydrocarbons in place, particularly heavy
hydrocarbons and kerogens, will still be in the formation. The
original production wells may continue to be used. Injection wells
would likely be established near or in areas previously fractured
as these are natural inducement pockets with connection to
production wells.
[0081] Oil shale formations comprising primarily kerogens are
treated very similar to bitumen carbonate formations. The Induced
Reactions process attacks the basic structure of the formation. The
decomposition of the rock creates heat, permeability, pressure and
formation fluids. Kerogens are exposed to the heat and the open
exit paths allow the recovery of economic amounts of hydrocarbons
from the pyrolyzed kerogen.
[0082] The present invention utilizes wells for three different
purposes--production, injection and Pipes Circuits. FIGS. 1 and 2
provide a horizontal and vertical view respectively of one
schematic layout of three types of wells--injection wells,
production wells and Pipes Circuit wells. A multi-well pad is well
known in the art. Several wells start on the surface in close
proximity to one another and extend down into the formation via
essentially vertical legs and then extend within the formation via
essentially horizontal legs. In the preferred embodiment of the
present invention, all the production wells 102 in FIG. 2 extend
vertically, from a multi-well pad 101, at the surface 105, down
through the overburden 106, to the lower part of a contained
hydrocarbon bearing formation 107 above an underburden 108.
[0083] In FIG. 1 all the production wells 102 then extend
essentially horizontally near the bottom of the formation 107, half
one direction from the multi-well pad 101, and half the opposite
direction from the multi-well pad 101. The horizontal legs of the
production wells 102, in each half, extend essentially parallel to
one another. The horizontal legs of production wells 102 may be
located at any elevation within the formation depending primarily
on the form of hydrocarbon targeted. The injection wells 104 are
vertical wells that extend vertically from various locations at the
surface 105, down through the overburden 106 into the formation
107.
[0084] As seen in FIG. 2 the Pipes Circuit wells 103 extend
vertically, from the multi-well pad 101 at the surface 105, down
through the overburden 106 to the upper part of the contained
hydrocarbon bearing formation 107. The Pipes Circuit wells 103 then
extend horizontally near the top of the formation 107, half in one
direction from the multi-well pad 101, and half in the opposite
direction from the multi-well pad 101. The horizontal legs of the
Pipes Circuit wells 103, in each half, extend essentially parallel
to one another. The spacing and locations of Pipes Circuit wells
will largely depend on the surface form, the use of the heat energy
and its scale. Approximately the same number of Pipes Circuit wells
as production wells may be the most efficient way to recover the
waste heat during and after the period that production wells are
economic to operate. However, fewer Pipes Circuit wells than
production wells may be most efficient. This is because the hot
gases created by the induced reactions will generally migrate
toward the upper part of the formation where the Pipes Circuits are
located. The injection wells may or may not be in a row running
parallel to the production and Pipes Circuit wells as shown in FIG.
1.
[0085] FIG. 3 illustrates the flow process to mobilize and produce
hydrocarbons using the Induced Reactions process in a subterranean
hydrocarbon-bearing formation 107 comprised primarily of solid
silicate and carbonate minerals. The formation may be a relatively
compact formation containing bitumen and/or other heavy
hydrocarbons that are in relatively solid form and plug the
majority of the pores of the resident rock, making the formation
relatively impermeable. The Grosmont and other bitumen carbonate
formations in Alberta are believed to contain examples of such
formations. The Induced Reactions process of the invention starts
with two situ chemical reactions, the silicate-reactions and the
carbonate-reactions. They will not begin to react in the reservoir
without inducement from the surface 105. To start these two
reactions and help them continue until they are self-sustaining and
on-going will usually require: a) a fractured inducement pocket,
and injections from the surface of: b) heat, c) CO.sub.2, d)
pressure, and possibly e) steam.
[0086] In one embodiment of the process, the formation area at the
bottom of the injection well 104 may be fractured in advance of the
inducement process. In a second embodiment, the formation area
adjacent to most of the length of the injection well 104 that is
contained in the formation 107 may be fractured in advance of the
inducement process. It is expected that normally such fracturing
should be done until fluid communication to the production well is
made.
[0087] As shown in FIG. 3, an electric heater 115 is lowered to the
bottom of the injection well 104 and is connected to a control
mechanism 125. The electric heater 115 creates intense heat in the
fractured space at the bottom of the injection well 104, referred
to herein as an inducement pocket 126. When sufficient heat has
been created in the inducement pocket, CO.sub.2 is flowed from a
storage facility 120 through a pipe 121 to a compressor 122. The
compressed CO.sub.2 flows through a pipe 123 to a pump 124. The
compressed CO.sub.2 is injected under pressure by the pump 124
through the wellhead of the injection well 104 and down to the
bottom of each injection well 104, close to, or through, the heater
115 and into the inducement pocket 126.
[0088] The prior art includes many methods to fracture and create a
down-hole space like the inducement pocket 126 and create heat,
pressure, CO.sub.2 and water/steam therein. Any of these prior art
methods may replace the above fracturing, use of an electric heater
and injection of CO.sub.2 under pressure.
[0089] The CO.sub.2, fracturing and injected pressure starts the
accelerated decomposition of the fractured silicate minerals, i.e.
the silicate-reactions, in the inducement pocket 126. The pressure
and heat created by the electric heater is also sufficient to start
the accelerated decomposition of the fractured carbonate minerals,
i.e. the carbonate-reactions, in the inducement pocket 126. As the
carbonate-reactions commence, some heat is absorbed and CO.sub.2
and related pressure is produced. As the silicate-reactions
commence, CO.sub.2 is absorbed, a great quantity of heat, H.sub.2
and O.sub.2 fluids and related additional pressure are
produced.
[0090] The carbonate-reactions generate CO.sub.2 and pressure to
help cause more silicate-reactions and the silicate-reactions
generate heat and pressure to help cause more carbonate-reactions.
Progressively less added CO.sub.2, heat and pressure will be needed
via the injection wells 104 from the surface as the silicate and
carbonate reactions themselves gradually generate enough heat,
CO.sub.2 and pressure to keep the induced-reactions occurring on a
self-sustaining basis.
[0091] As the silicate and carbonate reactions progress, the
inducement pocket 126 progressively changes. The solid and
impermeable silicate and carbonate minerals are slowly decomposed
and converted or transformed into gases, liquids and more porous
and permeable solids. The gases and liquids intermix to become the
formation fluids. The solid and impermeable heavy hydrocarbons are
freed from the decomposing rock structure and become exposed to the
heat and chemically aggressive products of silicate-reactions and
carbonate-reactions. Hydrocarbon-reactions commence. As additional
silicate-reactions gradually increase the temperature in the
inducement pocket 126, the light and medium hydrocarbons become
fluids and are thus mobilized to then join the formation
fluids.
[0092] The formation fluids along with related heat and pressure
that migrate through natural fractures 129 to a gas-pocket 128
start to react with some of the components of the rock structure
that comprise the edges of the natural fractures and the gas-pocket
128. To the extent induced fracturing above and near the production
wells has occurred and/or natural fractures 129 exist between an
inducement pocket and a gas-pocket 128 and production wells, some
formation fluids, especially gases containing the lightest
hydrocarbons, can flow to the production wells 102 at this
stage.
[0093] As the self-sustaining silicate-reactions and
carbonate-reactions progress in tandem with the related
hydrocarbon-reactions, each inducement pocket 126 and natural
fracture 129 gradually gets hotter and grows in size, enabling
progressively heavier hydrocarbons and other formation fluids to
flow to the gas-pockets, and to the production wells 102. New
gas-pockets 128 are created. Each gas-pocket gradually gets hotter
and grows in size as more formation fluids react with its rock
structure. Gradually, each gas-pocket 128 is absorbed into a
growing inducement pocket 126/130.
[0094] As the temperature in an inducement pocket gradually rises,
the induced-reactions accelerate the structural transformation of
immediately surrounding resident rock. At this stage, the
self-sustaining induced-reactions and an inducement pocket are best
described as structure-changing-reactions and a
structure-changing-chamber 130, respectively.
[0095] As the self-generating structure-changing-reactions
progress, the heat and the formation fluids in the
structure-changing-chambers create more exit paths 127 from each
structure-changing-chamber 130 and expand the size of the exit
paths in addition to expanding the size of, and raising the
temperature in, each structure-changing-chamber. More gas-pockets
128 get absorbed into structure-changing-chambers and new
gas-pockets are formed. Acids and other products in the formation
fluids react with the rock in the gas-pockets and increase the
permeability of the gas-pockets and in particular the exit paths
127, including natural fractures 129, therefrom.
[0096] At lower temperatures the lightest hydrocarbons are
subjected to pyrolysis and become part of the formation fluids that
migrate to the gas-pockets. Given the fracturing around the
injection wells, the light hydrocarbons and related less viscous
formation fluids will be the first to migrate via new and expanded
exit paths 127 and expanded natural fractures 129 to the production
wells 102. As the temperatures rise in the
structure-changing-chambers 130, pyrolysis and
hydrocarbon-reactions cause medium weight hydrocarbons to convert
from their solid form and become part of the formation fluids.
[0097] The higher temperatures in the structure-changing-chambers
and additional products in the formation fluids expand the exit
paths from the structure-changing-chamber to then more permeable
lower pressure gas-pockets. Structure-changing-reactions begin in
exit paths and gas-pockets.
[0098] The formation fluids, including medium hydrocarbons and more
acids and other products, continue to react with the rock they
encounter and further expand the gas-pockets, exit paths and
natural fractures. These permeability changes enable the more
viscous medium hydrocarbon-bearing formation fluids to migrate to
the lower pressure production wells 102.
[0099] As the structure-changing-reactions progress further, the
bitumen and other heavy hydrocarbons are more easily accessed by
the heat and products that cause hydrocarbon-reactions, because
more of the rock has been decomposed, and the temperatures and
pressure in the structure-changing-chambers are both higher. As a
result, the bitumen and heavy hydrocarbons become less viscous
fluids and thus more mobile. Eventually temperatures and produced
hydrogen will be sufficient in the first reaction areas that
thermal cracking and hydrocracking will commence to refine some of
the bitumen and heavy hydrocarbons, lower their viscosity and
increase the mobility of the related formation fluids bearing these
hydrocarbons.
[0100] In a progressive and gradual manner the
structure-changing-chambers 130 grow and merge and eventually the
entire reservoir may become a single large
structure-changing-chamber. It is quite possible that virtually all
the hydrocarbons will have been liquefied and produced before all
of the silicate and carbonate minerals have been converted to gases
and more permeable solids. It may be economic to continue to
produce the formation fluids with little or no hydrocarbon content
if the recoverable trace minerals, heat, hydrogen and oxygen
arising from continued silicate reactions are sufficient.
[0101] As formation fluids are delivered from the high pressure
reservoir 107 through the lower pressure production wells 102 to
the wellhead at the surface, the formation fluids may flow in
different sequences depending on the content, temperature and
pressure of the fluids. A heat exchanger 131 captures heat from the
fluids. One or more separators 132 remove the free hydrogen, free
oxygen, trace minerals, CO.sub.2 and other greenhouse gases and
water/steam from the hydrocarbons.
[0102] The separated hydrogen flows through a line 133 to a
compressor 157 and the compressed hydrogen will flow through a line
134 to a storage facility 135. Some hydrogen may flow through line
136 to a hydrocarbon upgrading or refining facility 137. The
separated hydrocarbons will flow through a line 138 to the refining
facility 137. The refining facility may use waste heat from the
Induced Reactions process directly via a Pipes circuit 103,
directly from the heat exchanger for formation fluids and/or be
powered by electricity delivered by a line 140 from the Pipes based
electric power plant 155.
[0103] The CO.sub.2 flows from the separator(s) 132 through a pipe
139 to the CO.sub.2 storage facility 120 where it may flow via pipe
121, compressor 122, pipe 123, pump 124 and pipe 124A to be
injected under pressure down an injection well 104 into the
reservoir to chemically cause additional silicate-reactions.
Alternately the CO.sub.2 may be injected into the reservoir for
permanent storage, after the heat has been mined by the Pipes
circuits 103.
[0104] The other greenhouse gases flow from the separators 132 via
a line 142 to a storage facility 143 and then via line 144 to a
compressor 145. Via line 146 the compressed greenhouse gases may be
injected down an injection well 104 for permanent storage. Trace
minerals of value such as sulfur and vanadium and gases such as
oxygen will flow from the separators 132 to storage 160 from which
they will be sold or used in a local process.
[0105] Referring to FIG. 4, each Pipes well 103 has a vertical leg
down to the upper part of the formation 107 and a horizontal leg
that usually runs along the upper part of the formation to the end
of the formation or property being produced. The bore hole 147 is
cased 148 for its entire length. The far end of the casing
horizontal leg has a plug 149. A pipe 154 is inserted inside the
casing creating an annulus 150 between the pipe and casing that has
essentially the same cross section area as the cross section of the
pipe. The far end 151 of the pipe 154 is open.
[0106] A working fluid such as water is stored in facility 152 from
which it flows to pump 153. The working fluid is pumped from the
surface 105 down the annulus 150 to the formation 107 where it will
be heated and become steam as it flows along the horizontal leg
through the formation to the plug 149. The critically hot steam
then flows through the open end 151 of the inner pipe 154 to the
surface without coming in direct contact with the formation rock or
with greenhouse gases and other pollutants or the hydrocarbons in
the reservoir 107. The heated fluid delivered by the Pipes system
may be used to generate electricity on a major or minor scale from
an on-site power plant 155, or for SAGD, or for a refinery 137 or
any other use requiring heat.
[0107] As will be apparent to those skilled in the art in light of
the foregoing disclosure, many alterations and modifications are
possible in the practice of this invention without departing from
the scope thereof. Accordingly, the scope of the invention is to be
construed in accordance with the following claims.
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