U.S. patent application number 12/424680 was filed with the patent office on 2009-10-22 for method for recovery of hydrocarbons from a subsurface hydrocarbon containing formation.
Invention is credited to Jingyu CUI, Mahendra Ladharam JOSHI, Stanley Nemec MILAM, Michael Anthony REYNOLDS, Scott Lee WELLINGTON.
Application Number | 20090260825 12/424680 |
Document ID | / |
Family ID | 40823519 |
Filed Date | 2009-10-22 |
United States Patent
Application |
20090260825 |
Kind Code |
A1 |
MILAM; Stanley Nemec ; et
al. |
October 22, 2009 |
METHOD FOR RECOVERY OF HYDROCARBONS FROM A SUBSURFACE HYDROCARBON
CONTAINING FORMATION
Abstract
Methods for treating a hydrocarbon containing formation are
described herein. A comprising hydrogen sulfide is combusted in one
or more surface facilities exterior to the hydrocarbon containing
formation to produce a sulfur oxides stream. At least a portion of
the sulfur oxides stream is provided to a hydrocarbon containing
formation. Steam may be provided to the hydrocarbon containing
formation. Mixing of the steam and/or water in the formation with
the sulfur oxides generates heat of solution in the hydrocarbon
containing formation for mobilizing formation fluids.
Inventors: |
MILAM; Stanley Nemec;
(Houston, TX) ; WELLINGTON; Scott Lee; (Bellaire,
TX) ; JOSHI; Mahendra Ladharam; (Katy, TX) ;
CUI; Jingyu; (Katy, TX) ; REYNOLDS; Michael
Anthony; (Katy, TX) |
Correspondence
Address: |
SHELL OIL COMPANY
P O BOX 2463
HOUSTON
TX
772522463
US
|
Family ID: |
40823519 |
Appl. No.: |
12/424680 |
Filed: |
April 16, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61046136 |
Apr 18, 2008 |
|
|
|
Current U.S.
Class: |
166/303 |
Current CPC
Class: |
E21B 43/24 20130101;
E21B 36/025 20130101; E21B 43/281 20130101; E21B 43/305 20130101;
E21B 43/20 20130101 |
Class at
Publication: |
166/303 |
International
Class: |
E21B 43/24 20060101
E21B043/24; E21B 36/00 20060101 E21B036/00; E21B 36/02 20060101
E21B036/02 |
Claims
1. A method of treating a hydrocarbon containing formation,
comprising: providing a fuel comprising hydrogen sulfide to one or
more surface facilities exterior to a hydrocarbon containing
formation; combusting at least a portion of the fuel comprising
hydrogen sulfide in the presence of an oxidant in at least one of
the surface facilities to produce at least one combustion
by-products stream comprising one or more sulfur oxides; contacting
at least a portion of the combustion by-products stream comprising
one or more sulfur oxides with water to generate heat; and
transferring the heat generated by contacting the combustion
by-products stream with water to the hydrocarbon containing
formation.
2. The method of claim 1 further comprising the step of: providing
a stream comprising steam to a portion of the hydrocarbon
containing formation, wherein at least a portion of the stream
comprising steam comprises at least a portion of the water
contacted with the combustion by-products stream to generate
heat.
3. The method claim 2 further comprising the step of providing at
least a portion of the combustion by-products stream comprising one
or more sulfur oxides to at least a portion of a hydrocarbon
containing formation; wherein at least a portion of the stream
comprising steam is contacted with the combustion by-products
stream in the hydrocarbon formation.
4. The method of claim 2, further comprising heating at least a
portion of the stream comprising steam with at least a portion of
the combustion by-products stream prior to providing the stream
comprising steam to the hydrocarbon containing formation.
5. The method of claim 2 wherein the at least a portion of the
stream comprising steam is contacted with the combustion
by-products stream in the wellbore adjacent the hydrocarbon
formation.
6. The method of claim 2 wherein at least a portion of the water
contacted with the combustion by-products stream is water present
in the hydrocarbon formation.
7. The method of claim 1 wherein at least a portion of the water
contacted with the combustion by-products stream is water present
in the hydrocarbon formation.
8. The method of claim 1, wherein the fuel comprises at least 1%
hydrogen sulfide by volume as determined by ASTM Method D2420.
9. The method of claim 1, wherein the fuel comprises elemental
sulfur.
10. The method of claim 1, wherein providing the combustion
by-products stream comprising one or more sulfur oxides comprises
introducing the combustion by-products stream comprising one or
more sulfur oxides into one or more wells in the hydrocarbon
containing formation positioned proximate a portion of hydrocarbon
formation containing the steam.
11. The method of claim 1, wherein providing the combustion
by-products stream comprising one or more sulfur oxides comprises
introducing combustion by-products stream comprising one or more
sulfur oxides into a downstream portion of a steam injection
well.
12. The method of claim 1, wherein at least one of the sulfur
oxides comprises sulfur dioxide and contacting comprises solvating
at least a portion of the formation fluids with the sulfur
dioxide.
13. The method of claim 1, further comprising the steps of
mobilizing at least a portion of hydrocarbons in the hydrocarbon
containing formation with the generated heat; and recovering at
least a portion of the mobilized hydrocarbons.
14. The method of claim 1, wherein the hydrogen sulfide is obtained
by separating the hydrogen sulfide from formation fluid produced
from hydrocarbon containing formations, gas reservoirs, surface
facilities, or combinations thereof.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from U.S. Provisional
Application Ser. No. 61/046,136 filed Apr. 18, 2008, which is
hereby incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to methods for recovery of
hydrocarbons from a subsurface hydrocarbon formation.
DESCRIPTION OF RELATED ART
[0003] Hydrocarbons obtained from subterranean formations are often
used as energy resources, as feedstocks, and as consumer products.
Concerns over depletion of available hydrocarbon resources have led
to development of processes for more efficient recovery,
processing, and/or use of available hydrocarbon resources.
[0004] Hydrocarbon formations may be treated in various ways to
produce formation fluids. For example, application of heat, gases,
and/or liquids to hydrocarbon formations to mobilize and/or produce
formation fluids has been used to more efficiently recover
hydrocarbons from hydrocarbon formations.
[0005] Combustion of fossil fuel and the resulting combustion
by-products may be used to heat a formation. The combustion may
take place in the formation, in a well, and/or near the surface.
Combustion of fossil fuel generates carbon dioxide as a combustion
by-product. Carbon dioxide is considered to have low economic value
and is considered a contributor to the "greenhouse effect".
Emissions such as carbon dioxide from fossil fuel combustion may be
treated and/or sequestered in a formation. For example, flue gas
from the combustion of fossil fuels has been used to displace heavy
oil and bitumen in a subterranean formation to enhance recovery of
the heavy oil and bitumen.
[0006] Combustion of sulfur compounds has also been used to heat a
hydrocarbon formation, where the sulfur containing combustion
products may act as a drive fluid for the more efficient production
of hydrocarbons from the hydrocarbon formation. U.S. Pat. No.
4,379,489 to Rollmann describes a method for recovery of heavy oil
from a subterranean reservoir that includes burning liquid sulfur
in an oxygen-containing gas underground to form sulfur dioxide. The
sulfur dioxide may act as a drive fluid for the recovery of oil or
it may react with limestone in the formation to form carbon
dioxide, an alternate drive fluid. The pressure of the
oxygen-containing gas is maintained at a pressure sufficient to
keep the sulfur dioxide in the liquid state.
[0007] An efficient, cost effective method for treating a
hydrocarbon formation to more efficiently recover hydrocarbons from
the hydrocarbon formation without the production of large
quantities of carbon dioxide is desirable.
SUMMARY OF THE INVENTION
[0008] The present invention is directed to a method of treating a
hydrocarbon containing formation comprising: providing a fuel
comprising hydrogen sulfide to one or more surface facilities
exterior to a hydrocarbon containing formation; combusting at least
a portion of the fuel comprising hydrogen sulfide in the presence
of an oxidant in at least one of the surface facilities to produce
at least one combustion by-products stream comprising one or more
sulfur oxides; contacting at least a portion of the combustion
by-products stream comprising one or more sulfur oxides with water
to generate heat; and transferring the heat generated by contacting
the combustion by-products stream with water to the hydrocarbon
containing formation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Further advantages of the present invention may become
apparent to those skilled in the art with the benefit of the
following detailed description of the preferred embodiments and
upon reference to the accompanying drawings in which:
[0010] FIG. 1 depicts a schematic of an embodiment of treating
formation fluids produced from a hydrocarbon formation.
[0011] FIG. 2 depicts a representation of an embodiment of heating
a portion of a hydrocarbon layer using a stream containing sulfur
oxides in combination with a steam injection well.
[0012] FIG. 3 depicts a representation of an embodiment for heating
a portion of a hydrocarbon layer using a well for introducing a
stream containing sulfur oxides in combination with a steam
injection well.
[0013] While the invention is susceptible to various modifications
and alternative forms, specific embodiments thereof are shown by
way of example in the drawings and may herein be described in
detail. The drawings may not be to scale. It should be understood,
however, that the drawings and detailed description thereto are not
intended to limit the invention to the particular form disclosed,
but on the contrary, the intention is to cover all modifications,
equivalents and alternatives falling within the spirit and scope of
the present invention as defined by the appended claims.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0014] The present invention is directed to providing subsurface
heat to a hydrocarbon formation where the heat is generated by
combusting a fuel stream comprising hydrogen sulfide and
transferring at least a portion of the heat of combustion to the
hydrocarbon formation. Since the fuel stream is sulfur based,
production of carbon dioxide is avoided upon combustion of the
sulfur containing components of the fuel stream, reducing the
overall production of carbon dioxide of the heating process
relative to processes that utilize a fuel stream comprised mostly
of hydrocarbons. Additional heat is provided to the hydrocarbon
formation by injecting the combustion by-product stream, which
includes sulfur oxides, into the hydrocarbon formation, where a
heat of solution is generated by mixing of the sulfur oxides in the
combustion by-product stream with water. The water that is mixed
with the combustion by-product stream may be provided along with
the combustion by-product stream to the hydrocarbon formation or
may be present in the hydrocarbon formation.
[0015] The process of oxidizing hydrogen sulfide through a
combustion process to a produce sulfuric acid may have a heat value
similar to methane combustion. For example, using data from "The
Chemical Thermodynamics of Organic Compounds" by Stull et al.;
Kreiger Publishing Company, Malabar Fla., 1987, pp. 220, 229, 230,
233 and 234, the enthalpies of reaction for the combustion of
methane and hydrogen sulfide can be calculated. Combustion of
methane produces carbon dioxide as a by-product, as shown by the
following reaction:
CH.sub.4+2O.sub.2.fwdarw.CO.sub.2+2H.sub.2O
(.DELTA.H.sub.rxn=-191.2 kcal/mol at 600.degree. K)
In contrast, oxidation (combustion) of hydrogen sulfide to form
sulfuric acid has a calculated reaction enthalpy as shown in the
following reaction:
H.sub.2S+2O.sub.2.fwdarw.H.sub.2SO.sub.4 (.DELTA.H.sub.rxn=-185.4
kcal/mol at 600.degree. K)
More heat may be generated upon mixing the sulfuric acid in water
by the heat of solution of sulfuric acid in water as shown
below:
H.sub.2SO.sub.4+H.sub.2O.fwdarw.50 wt % H.sub.2SO.sub.4
(.DELTA.H.sub.dil=-14.2 kcal/mol at 298.degree. K).
[0016] The total amount of heat content produced from the
combustion of hydrogen sulfide and the dissolution of the sulfuric
acid may range from -185 kcal/mol to -206 kcal/mol depending on the
amount of water used to produce the sulfuric acid. Combustion of
hydrogen sulfide as a fuel instead of methane in accordance with
the process of the present invention, therefore, may be used to
provide heat to a hydrocarbon formation in an amount comparable to
the combustion of methane while producing no carbon dioxide.
Furthermore, the use of fuels containing hydrogen sulfide in the
process of the present invention provides a method to dispose of
waste hydrogen sulfide from other processes (for example, sour gas
and/or hydrotreating effluent streams) without creating elemental
sulfur.
[0017] Terms used herein are as defined as follows.
[0018] "API gravity" refers to API gravity at 15.5.degree. C.
(60.degree. F.). API gravity is as determined by ASTM Method D6822
or ASTM Method D1298.
[0019] "ASTM" refers to American Standard Testing and
Materials.
[0020] A "formation" includes one or more hydrocarbon containing
layers, one or more non-hydrocarbon layers, an overburden, and/or
an underburden. "Hydrocarbon layers" refer to layers in the
formation that contain hydrocarbons. The hydrocarbon layers may
contain non-hydrocarbon material and hydrocarbon material. The
"overburden" and/or the "underburden" include one or more different
types of impermeable materials. In some cases, the overburden
and/or the underburden may be somewhat permeable.
[0021] "Formation fluids" refer to fluids present in a formation
and may include pyrolysis fluid, synthesis gas, mobilized
hydrocarbons, and water (steam). Formation fluids may include
hydrocarbon fluids as well as non-hydrocarbon fluids. The term
"mobilized fluid" refers to fluids in a hydrocarbon containing
formation that are able to flow as a result of treatment of the
formation. "Produced fluids" refer to fluids removed from the
formation.
[0022] A "heater" is any system or heat source for generating heat
in a well or a near wellbore region. Heaters may be, but are not
limited to, electric heaters, burners, combustors that react with
material in or produced from a formation, and/or combinations
thereof.
[0023] "Heavy hydrocarbons" are viscous hydrocarbon fluids. Heavy
hydrocarbons may include highly viscous hydrocarbon fluids such as
heavy oil, tar, and/or asphalt. Heavy hydrocarbons may include
carbon and hydrogen, as well as smaller concentrations of compounds
containing sulfur, oxygen, and nitrogen. Additional elements (for
example, nickel, iron, vanadium, or mixtures thereof) may also be
present in heavy hydrocarbons. Heavy hydrocarbons may be classified
by API gravity. Heavy hydrocarbons generally have an API gravity
below about 20. Heavy oil, for example, generally has an API
gravity of about 10-20, whereas tar generally has an API gravity
below about 10. The viscosity of heavy hydrocarbons is generally at
least 100 centipoise at 15.degree. C. Heavy hydrocarbons may
include aromatics or other complex ring hydrocarbons.
[0024] "Hydrocarbons" are generally defined as molecules formed
primarily by carbon and hydrogen atoms. Hydrocarbons as used herein
may also include metallic elements and/or other compounds that
contain, but are not limited to, halogens, nitrogen, oxygen, and/or
sulfur. Hydrocarbon compounds that contain sulfur are referred to
as "organosulfur compounds." Hydrocarbons may be, but are not
limited to, kerogen, bitumen, pyrobitumen, oils, natural mineral
waxes, and asphaltites. Hydrocarbons may be located in or adjacent
to mineral matrices in the earth. Matrices may include, but are not
limited to, sedimentary rock, sands, silicilytes, carbonates,
diatomites, and other porous media. "Hydrocarbon fluids" are fluids
that include hydrocarbons. Hydrocarbon fluids may include, entrain,
or be entrained in non-hydrocarbon fluids such as hydrogen,
nitrogen, carbon monoxide, sulfur oxides, carbonyl sulfide, carbon
dioxide, hydrogen sulfide, water, ammonia, or mixtures thereof.
[0025] As used herein, when two or more elements are described as
"operatively connected" the elements are defined to be directly or
indirectly connected to allow direct or indirect fluid flow between
the elements. The term "fluid flow" as used in the definition of
operatively connected refers to the flow of a gas or a fluid. As
used in the definition of "operatively connected" the term
"indirect fluid flow" means that the flow of a fluid or a gas
between two defined elements may be directed through one or more
additional elements to change one or more aspects of the fluid or
gas as the fluid or gas flows between the two defined elements.
Aspects of a fluid or a gas that may be changed in indirect fluid
flow include physical characteristics, such as the temperature or
the pressure of a gas or a fluid, and/or the composition of the gas
or fluid, e.g. by separating a component of the gas or fluid, for
example, by condensing water from a gas stream containing
steam.
[0026] "Oxidant" refers to compounds suitable to support
combustion. Examples of oxidants include air, oxygen, and/or
enriched air. "Enriched air" refers to air having a larger mole
fraction of oxygen than air in the atmosphere. Air is typically
enriched to increase combustion-supporting ability of the air.
[0027] "Tar" is a viscous hydrocarbon that generally has a
viscosity greater than about 10,000 centipoise at 15.degree. C. The
specific gravity of tar generally is greater than 1.000. Tar may
have an API gravity less than 10.
[0028] "Tar sands formation" refers to a formation in which
hydrocarbons are predominantly present in the form of heavy
hydrocarbons and/or tar entrained in a mineral grain framework or
other host lithology (for example, sand or carbonate). Examples of
tar sands formations include formations such as the Athabasca
formation, the Grosmont formation, and the Peace River formation,
all three in Alberta, Canada; and the Faja formation in the Orinoco
belt in Venezuela.
[0029] "Water" refers to the liquid and vapor phases of water. For
example, water, steam and super-heated steam.
[0030] In the process of the present invention, heat is provided to
a hydrocarbon containing formation. A fuel comprising hydrogen
sulfide is provided to one or more surface facilities exterior to
the hydrocarbon producing formation, and is combusted in the one or
more surface facilities in the presence of an oxidant to produce a
combustion by-products stream comprising one or more sulfur oxides.
At least a portion of the combustion by-products stream is
contacted with water to generate a heat of solution, and the
generated heat is transferred to the hydrocarbon formation. Heat
from the combustion of the fuel comprising hydrogen sulfide may
also be transferred to the hydrocarbon formation by contacting the
hot combustion by-products stream with the hydrocarbon formation or
by transferring heat from the hot combustion by-products stream to
water and then contacting the heated water with the hydrocarbon
formation. The heat provided to the hydrocarbon formation may be
utilized to mobilize formation fluids so that the formation fluids
may be collected and produced from the hydrocarbon formation.
[0031] A drive process may be used in conjunction with the process
of the present invention to treat hydrocarbon formations and to
mobilize and drive formation fluids to production wells so that the
formation fluids may be recovered from the hydrocarbon formation.
The drive process may include, but is not limited to, a steam
injection process such as cyclic steam injection, a steam assisted
gravity drainage process, a solvent injection process, or a vapor
solvent and steam assisted gravity drainage process; or a carbon
dioxide injection process.
[0032] The fuel comprising hydrogen sulfide utilized in the process
of the present invention may include from 1% to 100%, or from 3% to
90%, or from 10% to 80%, or from 20% to 50% of hydrogen sulfide by
volume; or at least 1%, or at least 5% or at least 10%, or at least
20%, or at least 25%, or at least 30% of hydrogen sulfide by
volume. Hydrogen sulfide content in a stream may be measured using
ASTM Method D2420. The fuel stream containing hydrogen sulfide may
contain hydrocarbons (for example, methane and ethane) and/or
hydrogen. The fuel stream comprising hydrogen sulfide may include
other sulfur containing compounds, for example sulfur oxides and
organosulfur compounds including methyl thiol, thiophene, thiophene
compounds, carbon disulfide, and carbonyl sulfide. The fuel stream
comprising hydrogen sulfide may have at least 0.1 grams, or at
least 0.3 grams, or at least 0.5 grams, or at least 0.7 grams, or
at least 0.9 grams of atomic sulfur per gram of fuel as determined
by ASTM Method D4294.
[0033] The fuel stream comprising hydrogen sulfide may be mixed
with elemental sulfur for combustion in the presence of an oxidant.
Mixing of the fuel stream comprising hydrogen sulfide and elemental
sulfur for combustion provides additional sulfur for the formation
of sulfur oxides to be combined with water to provide a heat of
solution to the hydrocarbon formation as well as additional heat of
combustion as shown in the following formula:
S+O.sub.2.fwdarw.SO.sub.2 (.DELTA.H.sub.rxn=-72.8 kcal/mol at
600.degree. K)
Additionally, combustion of elemental sulfur in combination with
the fuel stream comprising hydrogen sulfide in the process of the
present invention provides a method for disposing of elemental
sulfur, where such elemental sulfur may have accumulated from
processing of sulfur-contaminated hydrocarbons.
[0034] The fuel stream comprising hydrogen sulfide may also be
mixed with a hydrocarbon fuel stream for combustion in the presence
of an oxidant. The hydrocarbon fuel stream may comprise gaseous
hydrocarbons, and may include methane, ethane, propane, and
butane.
[0035] In the process of the present invention, the oxidant with
which the fuel stream comprising hydrogen sulfide is combusted is
an oxygen-containing gas or liquid. The oxidant is preferably
selected from compressed air, oxygen-enriched air, or oxygen gas.
Compressed air may be provided as the oxidant in the process of the
invention by compressing air by conventional air compressing
processes, for example, air may be compressed by passing the air
through a turbine compressor. Oxygen-enriched air, which may
contain from 0.5 vol. % to 15 vol. % more oxygen than air, may be
produced by compressing air and passing the compressed air through
a membrane that increases the amount of oxygen in the air. Oxygen
gas may be provided as the oxidant by conventional air separation
technology.
[0036] The surface facilities in which the fuel stream comprising
hydrogen sulfide is combusted in the presence of the oxidant may be
any conventional facility for effecting combustion of a fuel stream
comprising hydrocarbons that is equipped to handle combustion of
hydrogen sulfide. The surface facilities may include one or more
conventional combustor reactors in which the fuel stream comprising
hydrogen sulfide and the oxidant may be mixed, and the temperature
in the combustor reactor may be raised to a temperature above the
autoignition temperature of the mixture to initiate combustion of
the mixture.
[0037] The surface facilities are located exterior to the
hydrocarbon formation operatively connected to the hydrocarbon
formation in gaseous or liquid communication with the hydrocarbon
formation so that combustion by-products may be delivered from the
surface facilities to the hydrocarbon formation. The surface
facilities may also be in thermal communication with the
hydrocarbon formation so that heat from the combustion of the fuel
stream comprising hydrogen sulfide and the oxidant may be provided
to the hydrocarbon formation. In an embodiment, one or more
combustor reactors in one or more surface facilities are
operatively connected in gaseous or liquid communication with the
hydrocarbon formation through a wellbore that extends into the
hydrocarbon formation and is operatively connected in gaseous or
liquid communication with the hydrocarbon formation.
[0038] In the process of the present invention, combustion of the
fuel stream comprising hydrogen sulfide in the presence of an
oxidant produces a combustion by-products stream comprising sulfur
oxides. In some embodiments, the combustion by-products stream
includes from 1% to 100%, or from 3% to 90%, or from 10% to 80%, or
from 20% to 50% of sulfur oxides by volume, or at least 1%, or at
least 5%, or at least 10%, or at least 20%, or at least 25%, or at
least 30% of sulfur oxides by volume. The combustion by-products
stream may include, but is not limited to, hydrogen sulfide, sulfur
dioxide, sulfur trioxide, nitrogen, nitrogen oxide, carbon dioxide,
carbonyl sulfide, organosulfur compounds, water and/or oxygen.
[0039] The ratio of total sulfur to oxidant may be controlled
during the combustion process. By selecting the amount of total
sulfur (from the fuel comprising hydrogen sulfide and, optionally,
from elemental sulfur) relative to the amount of oxidant present-on
the basis of atomic sulfur to atomic oxygen ratio or on a
stoichiometric basis--and adjusting the amount of total sulfur to
the selected amount, the composition of the combustion by-products
produced (for example, hydrogen sulfide, sulfur dioxide and/or
sulfur trioxide) may be controlled. The amount of the fuel stream
comprising hydrogen sulfide may be controlled, the amount of
elemental sulfur may be controlled, and/or the amount the oxidant
stream may be controlled to produce a selected ratio of total
sulfur to oxidant for combustion such that a preferred combustion
by-product stream composition is produced.
[0040] The amounts of the fuel stream comprising hydrogen sulfide,
elemental sulfur, and the oxidant stream provided for combustion in
the process of the present invention may be controlled in a manner
such that combustion generates substantially sulfur trioxide in the
combustion by-product stream. To produce a sulfur trioxide-rich
combustion by-product stream, the ratio of total sulfur to oxidant
may be controlled so that excess oxidant is combusted relative to
the amount of total sulfur in the fuel stream comprising hydrogen
sulfide and the elemental sulfur. Combusting a total sulfur-lean
mixture produces more sulfur trioxide than sulfur dioxide as a
combustion by-product. The sulfur trioxide may react with water in
the hydrocarbon formation to form sulfuric acid. Sulfur trioxide is
readily converted to sulfuric acid, thus heat of solution may be
produced and delivered to the hydrocarbon formation more rapidly
than when the total sulfur amount combusted is a stoichiometric
amount or deficient amount relative to the amount of oxidant.
[0041] Alternatively, the amounts total sulfur and the oxidant
provided for combustion in the process of the present invention may
be controlled in a manner such that combustion generates
substantially sulfur dioxide in the combustion by-product stream.
To produce a sulfur dioxide-rich combustion by-product stream, the
ratio of hydrogen sulfide and elemental sulfur to oxidant may be
controlled so that a deficient amount of oxidant is combusted
relative to the total amount of sulfur. Using an excess of total
sulfur relative to oxidant produces a combustion by-products stream
rich in sulfur dioxide that also contains hydrogen sulfide, and
allows hydrogen sulfide and/or sulfur dioxide to be introduced into
a layer of the hydrocarbon containing formation. A portion of the
hydrogen sulfide and/or sulfur dioxide may contact at least a
portion of the formation fluids and solvate and/or dissolve a
portion of the heavy hydrocarbons in the formation fluids.
Solvation and/or dissolution of at least a portion the heavy
hydrocarbons may facilitate movement of the heavy hydrocarbons
towards the production well. Furthermore, introduction of at least
a portion of the combustion by-product stream comprising sulfur
dioxide into the formation fluids may increase a shear rate applied
to hydrocarbon fluids in the formation and decrease the viscosity
of non-Newtonian hydrocarbon fluids within the formation. The
sulfur dioxide may also drive formation fluids towards production
wells. The introduction of the sulfur dioxide rich combustion
by-products stream into the formation may thereby increase a
portion of the formation available for production, and may increase
a ratio of energy output of the formation (energy content of
products produced from the formation) to energy input into the
formation (energy costs for treating the formation).
[0042] In a further alternative, the amounts of the total sulfur
and the oxidant provided for combustion in the process of the
present invention may be controlled to provide stoichometrically
equivalent amounts of total sulfur and the oxygen. Combustion of a
stoichiometric amount of hydrogen sulfide with oxygen may generate
predominately sulfur dioxide and water as the combustion
by-products as shown in the following reaction:
H.sub.2S+1.5O.sub.2.fwdarw.SO.sub.2+H.sub.2O (.DELTA.H.sub.rxn=-124
kcal/mol at 600.degree. K).
In addition to the heat value that is obtained from combustion of
hydrogen sulfide, the introduction of heated sulfur dioxide/water
combustion by-product stream into the hydrocarbon formation may
facilitate recovery of hydrocarbons from the formation. The heat
from the sulfur dioxide may transfer heat to fluids in the
formation and the heated fluids may flow towards production wells.
Furthermore, as discussed above, the sulfur dioxide in the
combustion by-product stream may reduce the viscosity of
hydrocarbon formation fluids in the hydrocarbon formation and
thereby increase the amount of hydrocarbons available to be
recovered from the formation. The heat of solution of sulfur
dioxide, although less than the heat of solution of sulfuric acid,
may also be transferred to the formation fluids of the hydrocarbon
formation thereby mobilizing the formation fluids.
[0043] The combustion by-products stream is contacted with water to
generate heat, and the heat is transferred to the hydrocarbon
formation. A heat of solution is generated upon contact of the
combustion by-products stream with water. Combustion by-products
sulfur dioxide, sulfur trioxide, and sulfuric acid, formed by
contact of sulfur trioxide with water, generate a heat of solution
upon being mixed with water. In addition, heat from the combustion
of the fuel stream comprising hydrogen sulfide and the oxidant may
be transferred to the water by contacting hot combustion
by-products stream with the water to form steam or superheated
steam which then may be contacted with the hydrocarbon formation to
provide heat to the hydrocarbon formation. If desired, hot
combustion by-products from other combustion processes, e.g.
combustion of a fuel comprising hydrocarbons, may by combined with
the combustion by-products stream from combustion of the fuel
comprising hydrogen sulfide to provide additional heat to the
hydrocarbon formation.
[0044] The water with which the combustion by-products stream is
contacted to generate heat may be water present in the hydrocarbon
formation or may be water that is provided to the hydrocarbon
formation in conjunction with the combustion by-products stream. In
a preferred embodiment, the water is steam provided to the
hydrocarbon formation by a steam injection process, where the steam
and the combustion by-products stream are injected into a portion
of the hydrocarbon layer through a wellbore.
[0045] The combustion by-products stream, in conjunction with water
or alone, may be injected into a portion of the hydrocarbon
containing formation under pressure. The combustion by-products
stream may have a pressure, or may be pressurized to a pressure, of
at least 6 MPa, at least 10 MPa, or at least 12 MPa, or equal to
the formation pressure, and be injected into the hydrocarbon
formation at that pressure through a well or a steam injection
well. The combustion by-products stream may be introduced into one
or more wells located at depths below the hydrocarbon formation
surface of about 100, 200, 500, 1000, 1500, 2500, 5000, or 10000
meters. Heating the hydrocarbon containing formation at shallow
depths may allow recovery of hydrocarbons that are not readily
accessible through conventional hydrocarbon recovery methods.
[0046] In an embodiment of the process of the present invention,
the combustion by-products stream is injected into a portion of a
hydrocarbon formation in combination with a steam injection
process. The steam injection process may include steam drive,
cyclic steam injection, SAGD, or other processes of steam injection
into a hydrocarbon formation. The combustion by-products stream may
be injected into a portion of the hydrocarbon formation together
with the water/steam through one or more wells and/or the
combustion by-products stream and water/steam may be injected into
a portion of the hydrocarbon formation in separate wells so that
the combustion by-products mix with the injected water in the
hydrocarbon formation.
[0047] In an embodiment of the process of the present invention,
the combustion by-product stream comprising sulfur oxides and,
optionally, water/steam may be combined with carbon dioxide and
introduced into the hydrocarbon formation. Introduction of the
combustion by-product stream comprising sulfur oxides in
combination with steam and/or carbon dioxide may provide heat
and/or sufficient drive to mobilize heavy hydrocarbons in the
hydrocarbon layer.
[0048] Heat may be transferred to formation fluids (including
water), to fluids introduced into the formation, and/or to a
portion of the hydrocarbon containing formation through heat of
reaction, heat of solvation, conductive heat, or convective heat.
Fluids introduced into the formation and/or the combustion
by-products stream may transfer heat to at least a portion of the
hydrocarbon containing formation and/or formation fluids.
[0049] Convective heat transfer may occur when non-condensable
non-miscible gases such as nitrogen contact the formation fluids
and/or the hydrocarbon containing formation. When the oxidant
stream is formed of compressed air or oxygen-enriched air, the
combustion by-product stream may include nitrogen gas. Convective
heat transfer may also occur when superheated miscible solvent
vapors (for example, hydrogen sulfide, carbon dioxide, and/or
sulfur dioxide vapors) contact the formation fluids and/or the
hydrocarbon containing formation. Convective heat transfer may also
occur when superheated non-miscible solvent vapors such as water
contact the formation fluids and/or the hydrocarbon containing
formation.
[0050] Conductive heat transfer may occur when hot liquid steam
condensate contacts the formation fluids and/or the hydrocarbon
containing formation. Conductive heat transfer may occur when hot
liquid miscible solvent (for example, hydrogen sulfide, carbon
dioxide, and/or sulfur dioxide) contacts the formation fluids
and/or the hydrocarbon containing formation.
[0051] Heat of reaction heat transfer may occur when one compound
reacts with another compound. For example, sulfur oxides form
solutions with liquid water in the hydrocarbon containing formation
and/or with water/steam in the well to generate a heat of reaction.
Heat of reaction also occurs as oxygen reacts with hydrocarbons or
sulfur compounds to form carbon oxides or sulfur oxides.
[0052] Heat of solution may occur when at least one component is
dissolved in a solvent. For example, heat is generated when
sulfuric acid is dissolved in water.
[0053] Heat that is transferred to the hydrocarbon formation may
mobilize formation fluids. One or more production wells may be
located in a position to collect the mobilized formation fluids so
that the formation fluids may be recovered from the hydrocarbon
formation.
[0054] In an embodiment of the process of the present invention,
the fuel stream comprising hydrogen sulfide may be produced from a
hydrocarbon formation, preferably the hydrocarbon formation to be
heated by combustion of the fuel stream comprising hydrogen
sulfide. FIG. 1 depicts a schematic representation of treatment of
formation fluids produced from a hydrocarbon formation. The fuel
stream comprising hydrogen sulfide may be obtained by separating
the hydrogen sulfide from formation fluid produced from hydrocarbon
containing formations, gas reservoirs, surface facilities, or
combinations thereof. Formation fluid 100 produced from hydrocarbon
layer 102 enters fluid separation unit 104 and is separated into
liquid stream 106, gas stream 108 and aqueous stream 110. Liquid
stream 106 may be transported to other processing units and/or
storage units. Gas stream 108 may include, but is not limited to,
hydrocarbons, carbonyl sulfide, sulfur oxides, hydrogen sulfide,
organosulfur compounds, hydrogen, carbon dioxide, or mixtures
thereof. Gas stream 108 may enter gas separation unit 112 to
separate gas hydrocarbon stream 114 from the gas stream. In gas
separation unit 112, treatment of gas stream 108 separates at least
a portion of hydrogen sulfide stream 116, at least a portion of
carbon dioxide stream 118, at least a portion of sulfur dioxide
stream 120, and/or at least a portion of hydrogen stream 122 from
gas hydrocarbon stream 114. The gas separation unit may treat gases
from reservoirs, gas fields and/or waste streams from other surface
facilities.
[0055] Gas separation unit 112 may include a physical treatment
system and/or a chemical treatment system. The physical treatment
system includes, but is not limited to, a membrane unit, a pressure
swing adsorption unit, a liquid absorption unit, and/or a cryogenic
unit. The chemical treatment system may include units that use
amines (for example, diethanolamine or di-isopropanolamine), zinc
oxide, sulfolane, water, or mixtures thereof in the treatment
process. In some embodiments, gas separation unit 112 uses a
Sulfinol gas treatment process for removal of sulfur compounds.
Carbon dioxide may be removed using Catacarb.RTM. (Catacarb,
Overland Park, Kans., U.S.A.) and/or Benfield (UOP, Des Plaines,
Ill., U.S.A.) gas treatment processes. The gas separation unit may
be a rectified adsorption and high pressure fractionation unit.
Carbon dioxide stream 118 may be sequestered and/or used as a drive
fluid. Gas hydrocarbon stream 114 and/or hydrogen stream 122 may be
used as fuel. For example, gas hydrocarbon stream 114 and/or
hydrogen stream 122 may be combusted to heat water or drive
turbines to produce electricity. Gas hydrocarbon stream 114 may be
used as a fuel in downhole heaters to heat steam and/or layers of a
formation.
[0056] The gas separation unit 112 may use a regenerable process to
remove sulfur oxides from the gas stream. In such a process, at
least a portion of gas stream 108 contacts a material and/or
compound that adsorbs at least a portion of the sulfur dioxide from
the stream. The adsorbent may be treated to release the sulfur
dioxide to form sulfur dioxide stream 120. Sulfur dioxide stream
120 may include sulfur dioxide and some sulfur trioxide. In some
embodiments, sulfur dioxide stream 120 is separated from gas stream
108 using a process as described in U.S. Pat. No. 5,480,619 to
Johnson et al. and/or a Cansolv.RTM. SO.sub.2 Scrubbing System
(Cansolv Technologies, Montreal Canada). Sulfur dioxide stream 120
may contain at least 50% by volume, at least 80% by volume, or at
least 99% by volume of sulfur dioxide. Sulfur dioxide content in a
stream may be measured using ISO Method 7935. Sulfur dioxide stream
120 may be stored and/or combined with one or more streams to form
a concentrated sulfur dioxide stream.
[0057] Hydrogen sulfide stream 116 may be stored and/or combined
with one or more streams to form a concentrated hydrogen sulfide
stream. Hydrogen sulfide stream 116 may include from 1% to about
100%, from 3% to 90%, from 10% to 80%, or from 20% to 50% of
hydrogen sulfide by volume. Hydrogen sulfide content in a stream
may be measured using ASTM Method D2420. In some embodiments,
hydrogen sulfide stream 116 includes hydrocarbons (for example,
methane and/or ethane) and/or hydrogen. At least a portion of the
hydrogen sulfide stream 116 may be used as fuel for downhole
heaters.
[0058] The hydrogen sulfide stream 116 may be dried to remove
moisture. For example, hydrogen sulfide stream 116 may be dried by
contacting the hydrogen sulfide stream with ethylene glycol to
remove water.
[0059] At least a portion of hydrogen sulfide stream 116 enters
combustor 126. At least a portion of gas stream 108, at least a
portion of hydrocarbon stream 114 and/or at least a portion of
carbon dioxide stream 118 may enter combustor 126. In combustor
126, hydrogen sulfide stream 116, gas stream 108, hydrocarbon
stream 114, or mixtures thereof may be reacted with oxidant stream
124 to generate heat and combustion by-products stream 128. In some
embodiments, gas stream 108, hydrocarbon stream 114, and/or carbon
dioxide stream 118 are not used.
[0060] Combustion by-products stream 128 includes one or more
sulfur oxides. The combustion by-products stream 128 may include
sulfur dioxide, sulfur trioxide, hydrogen sulfide, oxygen, and/or
nitrogen. In some embodiments, at least a portion of sulfur dioxide
120 stream may be combined with a portion of combustion by-products
stream 128 to form a stream concentrated in sulfur dioxide.
[0061] Elemental sulfur may be combusted with the hydrogen sulfide
stream 116. Elemental sulfur may be provided to the combustor
and/or may be combined with hydrogen sulfide stream 116 and may be
burned in combustor 126 along with hydrogen sulfide stream 116 to
form combustion by-product stream 128. In some embodiments, the
combined hydrogen sulfide stream and elemental sulfur combusted in
combustor 126 have at least 0.1 grams, at least 0.3 grams, at least
0.5 grams, at least 0.7 grams, at least 0.9 grams or at least 0.99
grams of atomic sulfur per gram of combined hydrogen sulfide stream
116 and elemental sulfur as determined by ASTM Method D4294.
[0062] The heat generated from combustor 126 may be used to heat
water for a stream that includes steam. The stream may be used for
a drive process. Combusting the fuel that includes hydrogen sulfide
may produce at least 25% of the heat required to heat the stream
that includes steam. In some embodiments, at least 25%, at least
50%, at least 75%, at least 95% or all of the heat necessary to
heat water for the drive process, other surface facility processes,
other hydrocarbon recovery processes, or combinations thereof is
generated through the combustion of the fuel comprising hydrogen
sulfide stream 116 and, optionally, elemental sulfur.
[0063] In some embodiments, a method of treating a hydrocarbon
containing formation includes combusting a fuel having a sulfur
content of at least 0.1 grams of atomic sulfur per gram of fuel, in
one or more surface facilities to produce at least one combustion
by-products stream. The combustion by-products stream includes one
or more sulfur oxides. At least a portion of the sulfur oxides
stream is provided to at least a portion of a hydrocarbon
containing formation. A stream that includes steam is provided to a
plurality of wellbores in the hydrocarbon containing formation. At
least a portion of the sulfur oxides stream is contacted with at
least a portion of the steam provided to the hydrocarbon formation
and/or water in the formation to generate heat.
[0064] The composition of combustion by-products stream 128 to be
injected may be controlled. In some embodiments, the composition of
combustion by-products stream 128 to be injected may be controlled
by mixing various streams of hydrogen sulfide combustion products.
In some embodiments, the composition of combustion by-products
stream 128 is adjusted by combining sulfur dioxide stream 120 with
combustion by-products stream 128. In some embodiments, combustion
by-products stream 128 is heated and directly introduced into the
formation and/or a wellbore. In some embodiments at least a portion
of the fuel that includes hydrogen sulfide produces hot water and
further comprising providing at least a portion of the hot water to
the hydrocarbon containing formation.
[0065] FIGS. 2 and 3 depict representations of systems for
producing hydrocarbons from a hydrocarbon containing formation (for
example, a tar sands formation). Hydrocarbon layer 102 includes one
or more portions with heavy hydrocarbons. Hydrocarbon layer 102 may
be below overburden 130. Hydrocarbons may be produced from
hydrocarbon layer 102 using more than one process.
[0066] Hydrocarbons may be produced from a portion of hydrocarbon
layer 102 using a steam injection process. In the steam injection
process, a stream that includes steam 132 is introduced into
hydrocarbon layer 102 through openings 134 in injection well 136.
As shown in FIG. 2, the steam injection process uses a
substantially vertical well. It should be understood that any well
configuration (for example, substantially horizontal or
substantially diagonal) may be used. In some embodiments, the
terminus of steam injection well 136 is at a depth of below 100,
200, 500, 1000, 1500, 2500, 5000, or 10000 meters.
[0067] In some embodiments, heated carbon dioxide alone or in
combination with steam 132 is introduced into injection well 136.
Introduction of at least a portion of heated carbon dioxide may
facilitate movement of formation fluids to production well 138 by
heating, driving and/or reducing the viscosity of the formation
fluids. The injection of at least portion of the carbon dioxide
into the wellbore may be beneficial as an abatement of carbon
dioxide emissions. In some embodiments, steam 132 includes carbon
dioxide, nitrogen and/or sulfur dioxide. For example, steam 132 may
be combined with at least a portion of sulfur dioxide stream 120
and/or at least a portion of combustion by-products stream 128.
[0068] In some embodiments, a portion of hydrocarbon layer 102 is
treated using heaters prior to the steam injection process. Heaters
may be used to increase the temperature and/or permeability of a
portion of the hydrocarbon layer 102. Some hydrocarbons may be
produced through production well 138 by heating the hydrocarbon
layer. Formation fluids 100 removed through production well 138 may
be sent to surface facilities (as shown in FIG. 1). In some
embodiments, hydrocarbon layer 102 is not heated prior to steam
injection. The pattern and number of injection wells, heater wells
and production wells may be any number or geometry sufficient to
achieve production of formation fluids from a hydrocarbon
containing formation.
[0069] In some embodiments, injection well 136 includes a heater or
a series of heaters. In some embodiments, heaters are inserted in
injection well 136 after some hydrocarbons have been produced from
hydrocarbon layer 102. In some embodiments, heaters in injection
well 136 may combust fuel to heat steam injected in the injection
well.
[0070] In some embodiments, a portion of steam 132 is introduced
into injection well 136 at temperatures of at least 200.degree. C.,
at least 225.degree. C., at least 250.degree. C., or at least
260.degree. C. and at pressures ranging from about 1 MPa to about
15 MPa. The steam injected into the formation may move and/or drive
heavy hydrocarbon towards production well 138.
[0071] A portion of combustion by-products stream 128 may enter
injection well 136 via conduit 140. In some embodiments, sulfur
dioxide stream 120 is combined with combustion by-products stream
128. In some embodiments, at least a portion of the combustion
by-products stream that includes one or more sulfur oxides is mixed
with a stream that includes steam prior to providing the stream
comprising steam to the hydrocarbon containing formation.
[0072] In some embodiments, conduit 140 may include openings 142 to
allow combustion by-products stream 128 to mix with steam 132
and/or water present in the formation. Steam 132, the mixture of
steam 132 and combustion by-products stream 128, and/or the mixture
of combustion by-products stream and formation water may transfer
heat to hydrocarbon layer 102. Steam 132, the mixture of steam 132
and combustion by-products stream 128, and/or the combustion
by-products stream 128 itself enters into hydrocarbon layer 102
through openings 134 in injection well 136.
[0073] In some embodiments, combustion by-products stream 128 is
injected directly into steam 132 in injection well 136 and/or mixed
with steam 132 prior to injection into the injection well.
Combustion by-product streams from other processes may also be
combined with steam 132 prior to introduction of steam 132 into
injection well 136. Combining at least a portion of combustion
by-products stream 128 and, optionally, other combustion
by-products stream(s) provides heat to at least a portion of steam
132.
[0074] At least a portion of sulfur dioxide stream 120 may be
combined with a stream that includes steam 132 at the wellhead of
injection well 136 as well. Combining at least a portion of the
sulfur dioxide stream 120 with steam 132 may heat at least a
portion of the steam and provides the stream with an additional
formation fluid drive agent.
[0075] Openings 142 may be opened and/or closed to allow combustion
by-products stream 128 to be introduced into specific portions of
injection well 136 and/or hydrocarbon layer 102. The position of
conduit 140 may be adjusted to allow the conduit to be positioned
in various parts of the injection well 136. A portion of steam 132
may be introduced into the portion of injection well 136 between
the outer wall of conduit 140 and the inner wall of injection well
136.
[0076] In some embodiments, the portion between outer wall of
conduit 140 and inner wall of injection well 136 is a conduit that
communicates with the injection well and the conduit. A portion of
steam 132 and combustion by-products stream 128 may be introduced
into conduit 140 and between the outer wall of conduit 140 and the
inner wall of injection well 136.
[0077] As shown in FIG. 3, a portion of combustion by-products
stream 128 may enter injection well 144 positioned between
injection well 136 and production well 138 in hydrocarbon layer
102. Injection well 144 may include openings 146 to allow
combustion by-products stream 128 to enter the formation and mix
with formation water and/or with steam 132 as the steam flows into
the formation through openings 134 into hydrocarbon layer 102.
Mixing of steam, cooled steam, and/or formation water with the
combustion by-products stream releases heat into the hydrocarbon
formation.
[0078] Injection wells 136, 144 may be fabricated from materials
known in the art to be resistant to sulfur oxides. For example,
injection wells 136, 144 may be made from Hastelloy.RTM. C276,
alloy 230, alloy 800H, alloy 370H, nickel/copper/iron alloys, or
cobalt-chromium alloys.
[0079] Heat from steam 132 may form a first heated zone.
Hydrocarbons in hydrocarbon layer 102 may be mobilized by the heat
and produced from production well 138.
[0080] In some embodiments, sulfur oxides in combustion by-product
stream 128 in water may generate additional convective and/or
conductive heat in hydrocarbon layer 102 and form a second heated
zone. Heat from the second heated zone may transfer to a portion of
hydrocarbon layer 102 and mobilize formation fluids towards
production well 138.
[0081] Contact of at least a portion of the combustion by-products
stream 128 with water 132 may heat the water in injection well 136
and/or hydrocarbon layer 102 to form a second heated zone. The
second heated zone may heat a portion of the hydrocarbon layer 102
proximate the end of injection well 136 and/or extend into
hydrocarbon layer 102. Due to the heat from the combustion
by-products stream, an increased amount of hydrocarbons may be
produced per volume as compared to conventional drive fluid
processes. The first and second heat zones may overlap.
[0082] In some embodiments, the second heated zone is a substantial
distance from injection well 136. For example, the combustion
by-products stream may drive the steam into the formation. As the
steam condenses, the sulfur oxides in the combustion by-products
stream may react with the condensed water and/or water in the
formation to generate heat from the formation of sulfuric acid. The
sulfuric acid may mix with water and release heat of solution.
Released heat and/or generated heat from the combustion by-products
stream may heat the formation sufficiently to mobilize hydrocarbons
toward production well 138. The combination of steam heating in
combination with latent heating (heating after the steam condenses)
may facilitate recovery of hydrocarbons from the formation. The
combination of sensible heat for all introduced components and
latent heat may reduce energy and/or heating requirements for
producing hydrocarbons from the formation as compared to the energy
and/or heating requirements for conventional hydrocarbon recovery
processes.
[0083] In some embodiments, a portion of combustion by-products
stream 128 and/or sulfur dioxide stream 120 may be compressed to
form a liquid stream. Liquid sulfur dioxide may enhance dissolution
of organic compounds. In some embodiments, a portion of the sulfur
dioxide stream and/or a portion of the combustion by-products
stream may be compressed prior to injection into the hydrocarbon
formation and/or a wellbore.
[0084] In some embodiments, the formation contains limestone. As
the sulfur oxides contact the formation in the presence of water,
the limestone reacts with the sulfur oxides and produces carbon
dioxide. The carbon dioxide may serve as an additional drive fluid
to push the fluids towards production well 138.
[0085] In some embodiments, as the combustion by-products stream
and/or the sulfur dioxide stream is/are introduced into the
formation, the stream(s) may increase a shear rate applied to
hydrocarbon fluids in the formation and decrease the viscosity of
non-Newtonian hydrocarbon fluids within the formation. The
introduction of combustion by-products stream and/or the sulfur
dioxide stream(s) into the formation may increase a portion of the
formation available for production. Introduction of the combustion
by-products stream and/or the sulfur dioxide stream(s) may increase
a ratio of energy output of the formation (energy content of
products produced from the formation) to energy input into the
formation (energy costs for treating the formation).
[0086] In some embodiments, combustion of the fuel containing
hydrogen sulfide and hydrocarbon gases in the presence of the
oxidant produces a combustion by-products stream that includes
sulfur oxides, and other non-hydrocarbon gases, for example,
nitrogen, nitrogen oxide, organosulfur compounds, carbonyl sulfide,
and carbon dioxide. The production of carbon dioxide, nitrogen
and/or nitrogen oxide during combustion of hydrocarbons in the fuel
stream may facilitate heating steam 132, driving steam 132 into
hydrocarbon layer 102 and/or move formation fluids towards
production well 138.
[0087] Formation fluids (for example, heavy hydrocarbons) produced
from production well 138 may be treated in a surface facility (for
example, in surface facilities described in FIG. 1) to form a gas
stream and a liquid stream. The gas stream may include hydrogen
sulfide, hydrocarbon gases, sulfur dioxide, nitrogen, nitrogen
oxide, organosulfur compounds, carbonyl sulfide, and/or carbon
dioxide. Some of the gas stream may enter a combustor (for example,
see combustor 126 in FIG. 1). At least a portion of the sulfur
dioxide in the gas stream produced from production well 138 may be
oxidized in the presence of oxidant in the combustor 126 and form
combustion by-products stream 128 enriched in sulfur trioxide. The
enriched sulfur trioxide stream may be introduced into hydrocarbon
layer 102, mix with steam 132, and release heat of solution.
Recycling of sulfur dioxide in such a manner, provides a method to
substantially abate all of the sulfur emissions produced by
combustor 126, thus reducing emissions as compared to gas emissions
generated by combustion of hydrocarbons alone (for example,
generation of carbon dioxide).
[0088] In some embodiments, the sulfur dioxide is separated from
the produced gas stream in a surface facility (for example, in
surface facilities described in FIG. 1) to produce sulfur dioxide
stream 120 and combined with combustion by-products stream 128. In
some embodiments, the sulfur dioxide stream 120 is directly
introduced into injection well 144 and/or hydrocarbon containing
formation 102.
[0089] Steam 132 may include one or more surfactants and/or one or
more foaming agents. Surfactants include thermally stable
surfactants (for example, sulfonates, alkyl benzene sulfonates,
ethoxylated sulfates, and/or phosphates). The use of foaming agents
and/or surfactants may change the surface tension between the
hydrocarbons and the formation to facilitate mobilization of
hydrocarbons towards production well 138. A foaming agent may be
used to inhibit foaming of the formations fluids when carbon
dioxide and surfactants are present.
[0090] Steam 132 may include hydrogen sulfide and or hydrogen. The
hydrogen sulfide and/or hydrogen may solvate, dilute, and/or
hydrogenate a portion of the heavy hydrocarbons to form a mixture
that may move toward production well 138. Formation of the mixture
may increase production of hydrocarbons in hydrocarbon layer 102.
Solubilization, dilution and/or hydrogenation of a portion of the
heavy hydrocarbons may allow an increase in the amount of
hydrocarbons produced from the hydrocarbon layer. The solvents
and/or hydrogen sulfide may be separated from the mixture and
injected with steam 132 or used as a fuel in other processes and/or
for heaters. In some embodiments, heat from hydrogenation of
hydrocarbons transfers to a portion of hydrocarbon layer 102.
[0091] Further modifications and alternative embodiments of various
aspects of the invention will be apparent to those skilled in the
art in view of this description. Accordingly, this description is
to be construed as illustrative only and is for the purpose of
teaching those skilled in the art the general manner of carrying
out the invention. It is to be understood that the forms of the
invention shown and described herein are to be taken as examples of
embodiments. Elements and materials may be substituted for those
illustrated and described herein, parts and processes may be
reversed and certain features of the invention may be utilized
independently, all as would be apparent to one skilled in the art
after having the benefit of this description of the invention.
Changes may be made in the elements described herein without
departing from the spirit and scope of the invention as described
in the following claims.
* * * * *