U.S. patent application number 13/042096 was filed with the patent office on 2012-09-13 for carbon dioxide gas mixture processing with steam assisted oil recovery.
This patent application is currently assigned to ConocoPhillips Company. Invention is credited to David C. LaMont, Edward G. Latimer, James P. Seaba, Thomas J. Wheeler.
Application Number | 20120227964 13/042096 |
Document ID | / |
Family ID | 46794471 |
Filed Date | 2012-09-13 |
United States Patent
Application |
20120227964 |
Kind Code |
A1 |
LaMont; David C. ; et
al. |
September 13, 2012 |
CARBON DIOXIDE GAS MIXTURE PROCESSING WITH STEAM ASSISTED OIL
RECOVERY
Abstract
Methods and apparatus relate to processing flue gas from
oxy-fuel combustion. Steam generated without contact of the steam
with the flue gas combines with the flue gas for injection into a
formation to facilitate oil recovery from the formation. Fluids
produced include the oil and carbon dioxide with a lower
concentration of oxygen than present in the flue gas that is
injected.
Inventors: |
LaMont; David C.; (Calgary,
CA) ; Seaba; James P.; (Bartlesville, OK) ;
Wheeler; Thomas J.; (Houston, TX) ; Latimer; Edward
G.; (Ponca City, OK) |
Assignee: |
ConocoPhillips Company
Houston
TX
|
Family ID: |
46794471 |
Appl. No.: |
13/042096 |
Filed: |
March 7, 2011 |
Current U.S.
Class: |
166/272.3 ;
166/57 |
Current CPC
Class: |
E21B 43/2408
20130101 |
Class at
Publication: |
166/272.3 ;
166/57 |
International
Class: |
E21B 43/24 20060101
E21B043/24 |
Claims
1. A method, comprising: forming a mixture of flue gas from
oxy-fuel combustion and steam generated prior to being mixed with
the flue gas, wherein the flue gas contains carbon dioxide with an
initial concentration of oxygen that is at least 0.1 volume
percent; injecting the mixture into a subterranean formation for
heating oil in the formation and reacting with the oil at least
some of the oxygen that is from the flue gas and is dissolved in
liquid condensate of the steam; recovering fluids including the oil
that is heated and the carbon dioxide from the flue gas; separating
the fluids recovered to isolate from a liquid phase the carbon
dioxide containing less than the initial concentration of oxygen;
and transporting to a sequestration site the carbon dioxide that is
separated from the liquid phase.
2. The method according to claim 1, further comprising heating a
boiler for generating the steam using the oxy-fuel combustion.
3. The method according to claim 1, wherein the oxy-fuel combustion
is part of a heating unit separate from a steam generator that
makes the steam.
4. The method according to claim 1, wherein the separating the
fluids removes the liquid phase from a vapor phase that is at least
95% carbon dioxide by volume.
5. The method according to claim 1, wherein the separating the
fluids removes the liquid phase from a vapor phase that is at least
95% carbon dioxide by volume with oxygen content of less than
0.001% by volume.
6. The method according to claim 1, wherein the reacting of the oil
with at least some of the oxygen is at a temperature of at least
100.degree. C.
7. The method according to claim 1, wherein the reacting of the oil
with at least some of the oxygen is at a temperature of at least
200.degree. C.
8. The method according to claim 1, wherein at least 90% by volume
of the flue gas is the carbon dioxide.
9. The method according to claim 1, further comprising adding to
the mixture a hydrocarbon-containing solvent for the oil being
produced and having a lower viscosity than the oil being
produced.
10. The method according to claim 1, wherein the transporting
includes passing the carbon dioxide through a pipeline.
11. The method according to claim 1, wherein the injecting is
through a first wellbore spaced from a second wellbore located
deeper in the formation than the first wellbore and through which
the recovering occurs.
12. A method, comprising: producing flue gas from oxy-fuel
combustion, wherein the flue gas contains carbon dioxide with
quantities of oxygen greater than a transport specification;
generating steam without contact of the steam with the flue gas;
introducing the steam into the flue gas to form a mixture;
injecting the mixture into a formation for heating oil in the
formation; recovering fluids including the oil that is heated and
the carbon dioxide from the flue gas; separating the fluids into
liquids and vapors, which are formed of the carbon dioxide and meet
the transport specification due to removal of at least some of the
oxygen by oxidation of the oil upon the oxygen being dissolved in
condensate of the steam for liquid phase reactions at temperatures
elevated by the steam; and transporting to a sequestration site the
carbon dioxide obtained by the separating.
13. The method according to claim 12, wherein the transportation
specification is oxygen content of less than 0.001% by volume.
14. The method according to claim 12, wherein the separating the
fluids removes the liquids from the vapors that are at least 95%
carbon dioxide by volume.
15. The method according to claim 12, wherein the oxy-fuel
combustion is used to heat a boiler for the generating of the
steam.
16. The method according to claim 12, wherein at least 90% by
volume of the flue gas is the carbon dioxide and at least 0.1% by
volume of the flue gas is the oxygen.
17. The method according to claim 12, wherein the transporting
includes passing the carbon dioxide through a pipeline.
18. The method according to claim 12, wherein the elevated
temperatures are above 150.degree. C.
19. A system, comprising: a supply of flue gas from an oxy-fuel
combustion chamber; a source of steam generated without contact of
the steam with the flue gas; an injection well disposed in a
subterranean formation containing oil, wherein the injection well
is coupled in fluid communication with the supply of the flue gas
and the source of the steam; and a vapor-liquid separator coupled
to receive produced fluids heated by the steam and output carbon
dioxide from the flue gas, wherein the carbon dioxide in the
produced fluids is processed by liquid phase reactions between the
oil heated by the steam and at least some oxygen that is from the
flue gas and is dissolved in condensate of the steam.
20. The system according to claim 19, wherein the oxy-fuel
combustion chamber is coupled to heat a boiler for generating the
steam.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] None
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] None
FIELD OF THE INVENTION
[0003] Embodiments of the invention relate to methods and systems
for processing carbon dioxide in flue gas from oxy-fuel combustion
utilizing steam assisted oil recovery.
BACKGROUND OF THE INVENTION
[0004] Oxy-fuel combustion refers to burning of fuel in oxygen
(e.g., 95% pure oxygen) instead of air to reduce amount of nitrogen
in resulting flue gas. The flue gas from the oxy-fuel combustion
thus contains carbon dioxide and water vapor, which can be removed
if condensed through cooling. The oxy-fuel combustion facilitates
carbon dioxide capture since the flue gas is almost pure carbon
dioxide with trace amounts of impurities, such as oxygen (e.g.,
about 0.1-2 volume percent) remaining due to equilibrium
constraints as well as local mixing conditions during
combustion.
[0005] The oxygen in the carbon dioxide makes transportation of the
carbon dioxide to a sequestration site problematic since the oxygen
causes corrosion. Common carbon dioxide quality specifications for
pipeline transport require oxygen content to be below 0.001 by
volume. Cryogenic distillation provides one option for removing the
oxygen but requires additional expense and results in loss of 7-10
percent of the carbon dioxide.
[0006] Alternate approaches utilize the flue gas from the oxy-fuel
combustion. For example, injecting the flue gas into reservoirs of
natural gas helps displace the natural gas. However, gas phase
interactions of the flue gas in the reservoirs and the interactions
not occurring at where the reservoir is being heated limits any
possible oxygen removal from the carbon dioxide.
[0007] Therefore, a need exists for improved methods and systems
for processing carbon dioxide for capture.
SUMMARY OF THE INVENTION
[0008] In one embodiment, a method includes forming a mixture of
flue gas from oxy-fuel combustion and steam generated prior to
being mixed with the flue gas. The flue gas contains carbon dioxide
with an initial concentration of oxygen that is at least 0.1 volume
percent. Injecting the mixture into a subterranean formation heats
oil in the formation and reacts with the oil at least some of the
oxygen that is from the flue gas and is dissolved in liquid
condensate of the steam. The method further includes recovering
fluids including the oil that is heated and carbon dioxide from the
flue gas and separating the fluids recovered to isolate from a
liquid phase the carbon dioxide containing less than the initial
concentration of oxygen for transporting the carbon dioxide to a
sequestration site.
[0009] According to one embodiment, a method includes producing
flue gas from oxy-fuel combustion, generating steam without contact
of the steam with the flue gas, and introducing the steam into the
flue gas to form a mixture. The flue gas contains carbon dioxide
with quantities of oxygen greater than a transport specification.
In addition, the method includes injecting the mixture into a
subterranean formation for heating oil in the formation, recovering
fluids including the oil that is heated and the carbon dioxide from
the flue gas, and separating the fluids into liquids and vapors.
The vapors formed of the carbon dioxide meet the transport
specification due to removal of at least some of the oxygen by
oxidation of the oil upon the oxygen being dissolved in condensate
of the steam for liquid phase reactions at temperatures elevated by
the steam. The method further includes transporting to a
sequestration site the carbon dioxide obtained by the
separating.
[0010] For one embodiment, a system includes a supply of flue gas
from an oxy-fuel combustion chamber, a source of steam generated
without contact of the steam with the flue gas, and an injection
well disposed in a subterranean formation containing oil. The
injection well couples in fluid communication with the supply of
the flue gas and the source of the steam. A vapor-liquid separator
of the system receives produced fluids heated by the steam. The
vapor-liquid separator also outputs carbon dioxide that is in the
produced fluids from the flue gas and is processed by liquid phase
reactions between the oil heated by the steam and at least some
oxygen that is from the flue gas and is dissolved in condensate of
the steam.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The invention, together with further advantages thereof, may
best be understood by reference to the following description taken
in conjunction with the accompanying drawings.
[0012] FIG. 1 is a schematic of a production system for both
purification of carbon dioxide in flue gas and steam assisted oil
recovery, according to one embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0013] Embodiments of the invention relate to methods and systems
for processing flue gas from oxy-fuel combustion. Steam generated
without contact of the steam with the flue gas combines with the
flue gas for injection into a formation to facilitate oil recovery
from the formation. Fluids produced include the oil and carbon
dioxide with a lower concentration of oxygen than present in the
flue gas that is injected.
[0014] FIG. 1 illustrates a system with an injection well 101 and a
production well 102 that traverse through an earth formation 103
containing petroleum products, such as heavy oil or bitumen. The
system further includes a steam generator 104 to supply a flow of
steam 105 to the injection well 101. The steam generator 104 and/or
a separate heating unit 106 produce flue gas 107 from oxy-fuel
combustion.
[0015] The oxy-fuel combustion produces the flue gas 107 containing
carbon dioxide with at least 0.1 volume percent oxygen as a result
of burning fuel in oxygen, such as at least about 95% by volume
pure oxygen separated from air. The carbon dioxide may make up by
volume at least about 85%, at least about 90%, or at least about
95% of the flue gas 107. Sources for the fuel include coal,
petroleum coke, asphaltenes, methane, natural gas and hydrogen. To
limit resulting flame temperatures to levels common during
conventional combustion and within thermal thresholds, some cooled
combustion gases may circulate back and be injected into a
combustion chamber used for the oxy-fuel combustion.
[0016] For some embodiments, a burner heats a boiler within the
steam generator 104 for making the steam 105 without initial
contact of the flue gas 107 with the steam 105 in the steam
generator 104 since an inside of the boiler is sealed from the
burner, which may define the chamber for the oxy-fuel combustion.
The flue gas 107 combines with the steam 105 to form a mixture
after the steam 105 is generated. The mixture passes into the
injection well 101 upon introducing the flue gas 107 into the steam
105 between the steam generator 104 and the injection well 101. The
mixture may in some embodiments further contain a solvent for the
products added to help mobilize the products, which are more
viscous than the solvent. Examples of the solvent introduced into
the mixture include hydrocarbons, such as at least one of propane,
butane, pentane, hexane, heptane, naphtha, natural gas liquids and
natural gas condensate.
[0017] In operation, the mixture makes the petroleum products
mobile enough to enable or facilitate recovery with, for example,
the production well 102. For some embodiments, the injection well
101 includes a horizontal borehole portion that is disposed above
(e.g., 0 to 6 meters above) and parallel to a horizontal borehole
portion of the production well 102. While shown in an exemplary
steam assisted gravity drainage (SAGD) well pair orientation, some
embodiments utilize other configurations of the injection well 101
and the production well 102, which may be combined with the
injection well 101 or arranged crosswise relative to the injection
well 101, for example.
[0018] A vapor chamber develops in the formation 103 and grows as
the products are recovered. Walls of the vapor chamber form an
interface with the products where the steam 105 condenses
transferring heat to the products that then drain to the production
well 102. Since the flue gas 107 containing the oxygen is injected
into the vapor chamber during development of the chamber, the
oxygen contacts this condensate of the steam 105 and is dissolved
in the condensate enabling both the condensate to carry oxygen into
the products and liquid phase reaction of the oxygen with the
products. For some embodiments, effective removal of the oxygen
from the carbon dioxide in the flue gas 107 relies on the reactions
being in liquid phase compared to inefficient gas contact of the
oxygen with the products.
[0019] In some embodiments, this oxidation of the products further
depends on temperature at which the oxygen contacts the products
since oxygen uptake by the products increases with rising
temperature. The reactions for some embodiments occur at
temperatures that are elevated by the steam 105 and may be above
about 100.degree. C., above about 150.degree. C. or above about
200.degree. C. Injection of the flue gas 107 through a separate
well and outside of the vapor chamber formed by the steam 105
heating the products tends to keep the oxygen in gas phase and
insulated from thermal heating by the steam 105 due to physical
separation of the oxygen from the condensate. Likewise, injection
of the flue gas 107 after stopping injection of the steam 105
prevents ability of the oxygen to be dissolved in the condensate
and carried into the products at as high a temperature as possible.
While helpful for processing the carbon dioxide in the flue gas
107, the oxidation of the products lacks influence on recovery due
to only trace amounts of the oxygen in the flue gas 107.
[0020] As a benefit to recovery, the carbon dioxide from the flue
gas 107 also dissolves into the products reducing viscosity of the
products to facility production. The formation 103 retains some
amount of the carbon dioxide from the flue gas 107. Pore space
opened from one barrel of produced oil stores about 8 kilograms of
the carbon dioxide. Unlike loss of carbon dioxide associated with
cleaning of the flue gas 107 above ground to remove oxygen, the
carbon dioxide being held in the formation 103 remains sequestered
without requiring any additional treatment to be captured.
[0021] Fluid recovered from the production well 102 enters into a
separator 110 for separation of a liquid phase 111 from a vapor
phase 112. The liquid phase 111 includes the petroleum products and
water, which may be separated from the products and recycled along
with any solvent removed from the products. The carbon dioxide from
the flue gas 107 forms the vapor phase 112 and may make up by
volume at least about 90%, or at least about 95% of the vapor phase
112. Lack of substantial quantities of nitrogen in the flue gas 107
due to the oxy-fuel combustion limits nitrogen amounts in the vapor
phase 112 ensuring that the carbon dioxide therein remains
concentrated for desired capture and sequestration.
[0022] Due to the oxidation reactions discussed herein, the vapor
phase 112 contains a lower concentration of the oxygen than is
present in the flue gas 107 prior to introduction into the
injection well 101. In some embodiments, the flue gas 107 with the
at least 0.1 volume percent oxygen before being introduced into the
injection well 101 prevents the flue gas 107 from meeting transport
specifications. For example, oxygen content of above 0.001% by
volume in the flue gas 107 as produced from the oxy-fuel combustion
may reduce to below 0.001% by volume in the vapor phase 112 and
thereby be below the transport specifications.
[0023] This reduction in oxygen content processes the carbon
dioxide to enable transporting the carbon dioxide without further
oxygen removal from the vapor phase 112. For some embodiments,
transport of the carbon dioxide includes compressing the vapor
phase 112 that is then passed through a pipeline. The pipeline may
carry the carbon dioxide to a sequestration facility such as a
geologic reservoir distant from the formation 103 in which the
products are recovered.
[0024] In some embodiments, injection of the flue gas 107 from the
oxy-fuel combustion into a depleted hydrocarbon reservoir passes
the flue gas 107 into contact with unrecovered petroleum products
that react with the oxygen from the flue gas 107. Such oxidation
scrubs oxygen from the flue gas 107 leaving the carbon dioxide that
may be subsequently recovered for transporting even though no
hydrocarbons are also produced while recovering the carbon dioxide.
If only such scrubbing of the flue gas 107 and not recovering of
the petroleum products is desired, some embodiments may inject the
flue gas 107 without mixing the flue gas 107 with the steam
105.
[0025] The preferred embodiment of the present invention has been
disclosed and illustrated. However, the invention is intended to be
as broad as defined in the claims below. Those skilled in the art
may be able to study the preferred embodiments and identify other
ways to practice the invention that are not exactly as described
herein. It is the intent of the inventors that variations and
equivalents of the invention are within the scope of the claims
below and the description, abstract and drawings are not to be used
to limit the scope of the invention.
* * * * *