U.S. patent application number 13/239018 was filed with the patent office on 2012-03-29 for situ hydrocarbon upgrading with fluid generated to provide steam and hydrogen.
This patent application is currently assigned to ConocoPhillips Company. Invention is credited to Joe D. Allison, Wayne Reid Dreher, JR., Scott Macadam, James P. Seaba.
Application Number | 20120073810 13/239018 |
Document ID | / |
Family ID | 45869454 |
Filed Date | 2012-03-29 |
United States Patent
Application |
20120073810 |
Kind Code |
A1 |
Macadam; Scott ; et
al. |
March 29, 2012 |
SITU HYDROCARBON UPGRADING WITH FLUID GENERATED TO PROVIDE STEAM
AND HYDROGEN
Abstract
Methods and apparatus relate to recovery of in situ upgraded
hydrocarbons by injecting steam and hydrogen into a reservoir
containing the hydrocarbons. A mixture output generated as water is
vaporized by direct contact with flow from fuel-rich combustion
provides the steam and hydrogen. The steam heats the hydrocarbons
facilitating flow of the hydrocarbons and reaction of the hydrogen
with the hydrocarbons to enable hydroprocessing prior to recovery
of the hydrocarbons to surface.
Inventors: |
Macadam; Scott;
(Bartlesville, OK) ; Seaba; James P.;
(Bartlesville, OK) ; Dreher, JR.; Wayne Reid;
(College Station, TX) ; Allison; Joe D.;
(Fulshear, TX) |
Assignee: |
ConocoPhillips Company
Houston
TX
|
Family ID: |
45869454 |
Appl. No.: |
13/239018 |
Filed: |
September 21, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61386361 |
Sep 24, 2010 |
|
|
|
Current U.S.
Class: |
166/272.3 ;
166/57 |
Current CPC
Class: |
E21B 43/305 20130101;
E21B 43/2406 20130101 |
Class at
Publication: |
166/272.3 ;
166/57 |
International
Class: |
E21B 43/24 20060101
E21B043/24 |
Claims
1. A method, comprising: generating a hydrogen and steam containing
injection stream by vaporization of water contacted with flow from
combustion of a gaseous hydrocarbon fuel with an oxidant and at an
oxygen:fuel equivalence ratio less than 1; introducing the
injection stream into a formation to contact, heat and hydroprocess
hydrocarbons in the formation; recovering to surface the
hydrocarbons that have been upgraded.
2. The method according to claim 1, wherein the oxygen:fuel
equivalence ratio is less than 0.95.
3. The method according to claim 1, wherein the injection stream
contains at least 5 volume percent hydrogen on a dry basis.
4. The method according to claim 1, wherein the injection stream
contains at least 15 volume percent hydrogen on a dry basis.
5. The method according to claim 1, further comprising disposing a
hydroprocessing catalyst in a flow path of the hydrocarbons from
the formation to the surface.
6. The method according to claim 1, further comprising disposing a
water-gas shift catalyst in a flow path of the injection
stream.
7. The method according to claim 1, further comprising subsurface
heating of the hydrocarbons with a non-steam based heat source.
8. The method according to claim 1, wherein the introducing and the
recovering are through a steam assisted gravity drainage well
pair.
9. The method according to claim 1, further comprising disposing a
hydroprocessing catalyst along a producer wellbore through which
the hydrocarbons are recovered and heating the hydrocarbons in
contact with the catalyst to a reaction temperature above an
injection temperature that the injection stream enters the
formation.
10. The method according to claim 1, further comprising disposing a
water-gas shift catalyst in a flow path of the injection stream and
disposing a hydroprocessing catalyst that is different from the
water-gas shift catalyst in a flow path of the hydrocarbons from
the formation to the surface.
11. The method according to claim 1, further comprising subsurface
heating of the hydrocarbons to above 300.degree. C.
12. The method according to claim 1, further comprising subsurface
heating of the hydrocarbons to above 400.degree. C.
13. The method according to claim 1, wherein the hydrogen
facilitates hydroprocessing reactions that include desulfurization,
olefin and aromatic saturation and hydrocracking
14. A system, comprising: a hydrogen and steam generator having an
output of an injection stream produced by vaporization of water
contacted with flow from combustion of a gaseous hydrocarbon fuel
with an oxidant and at an oxygen:fuel equivalence ratio less than
1; an injector configured to convey the injection stream into a
formation to contact, heat and hydroprocess hydrocarbons in the
formation, and a recovery assembly that produces to surface the
hydrocarbons that are upgraded.
15. The system according to claim 14, further comprising a
hydroprocessing catalyst disposed in a flow path of the
hydrocarbons from the formation to the surface.
16. The system according to claim 14, further comprising a
non-steam based heat source for subsurface heating of the
hydrocarbons.
17. A method, comprising: injecting hydrogen and steam into a first
wellbore of a steam assisted gravity drainage well pair, wherein
the steam and hydrogen are generated by operation of a direct steam
generator under fuel-rich conditions; and recovering upgraded
hydrocarbons to surface through a second wellbore of the steam
assisted gravity drainage well pair.
18. The method according to claim 17, wherein the first wellbore
extends horizontal spaced from the second wellbore that extends
horizontal deeper in the formation than the first wellbore.
19. The method according to claim 17, further comprising heating
the hydrocarbons to a reaction temperature above an injection
temperature that the injection stream enters the formation.
20. The method according to claim 17, further comprising disposing
a hydroprocessing catalyst in a flow path of the hydrocarbons from
the formation to the surface.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a non-provisional application which
claims the benefit of and priority to U.S. Provisional Application
Ser. No. 61/386,361 filed Sep. 24, 2010, entitled "In Situ
Hydrocarbon Upgrading with Fluid Generated to Provide Steam and
Hydrogen," which is hereby incorporated by reference in its
entirety.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] None
FIELD OF THE INVENTION
[0003] Embodiments of the invention relate to methods and systems
for delivering hydrogen and steam to a subsurface reservoir for
upgrading of hydrocarbons in situ.
BACKGROUND OF THE INVENTION
[0004] In order to recover oil from certain geologic formations,
injection of steam increases mobility of the oil within the
formation via an exemplary process known as steam assisted gravity
drainage (SAGD). Produced fluids include the oil and condensate
from the steam. Surface handling of the produced fluids separates
the oil from water that may be recycled to generate additional
steam for sustaining the process.
[0005] Viscosity reduction obtained during production by heating
the oil with the steam is based on temperature of the oil and
therefore temporary. Subsequent transport of the oil through a
pipeline, for example, thus relies on diluting the oil with less
viscous hydrocarbons. However, blending the oil creates problems
due to added costs, potential to cause fouling and optimization
issues at refineries utilizing such blends as feedstock.
[0006] In situ upgrading of the oil offers permanent viscosity
reduction to facilitate transportation thereof and improves
refinery demand for the oil. Extent of the in situ upgrading in
past approaches depends on various factors including presence of a
hydrogen donor within the formation for reacting with the oil to
yield products that are upgraded. However, cost of generating
hydrogen at a surface facility, difficulty in transporting hydrogen
or expense of compounds that function as the hydrogen donor make
prior techniques to supply the hydrogen donor where wanted in the
formation undesirable.
[0007] Therefore, a need exists for methods and systems of
recovering subsurface upgraded oil from a reservoir.
BRIEF SUMMARY OF THE DISCLOSURE
[0008] In one embodiment, a method of in situ upgrading
hydrocarbons includes generating a hydrogen and steam containing
injection stream by vaporization of water contacted with flow from
combustion of a gaseous hydrocarbon fuel with an oxidant and at an
oxygen:fuel equivalence ratio less than 1. The method further
includes introducing the injection stream into a formation to
contact, heat and hydroprocess hydrocarbons in the formation. In
addition, the method includes recovering to surface the
hydrocarbons that have been upgraded.
[0009] According to one embodiment, a system for in situ upgrading
hydrocarbons includes a hydrogen and steam generator having an
output of an injection stream produced by vaporization of water
contacted with flow from combustion of a gaseous hydrocarbon fuel
with an oxidant and at an oxygen:fuel equivalence ratio less than
1. An injector conveys the injection stream into a formation to
contact, heat and hydroprocess hydrocarbons in the formation. A
recovery assembly produces to surface the hydrocarbons that are
upgraded.
[0010] For one embodiment, a method of in situ upgrading
hydrocarbons includes injecting hydrogen and steam into a first
wellbore of a steam assisted gravity drainage well pair. Operation
of a direct steam generator under fuel-rich conditions generates
the steam and hydrogen. The method also includes recovering
upgraded hydrocarbons to surface through a second wellbore of the
steam assisted gravity drainage well pair.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] A more complete understanding of the present invention and
benefits thereof may be acquired by referring to the following
description taken in conjunction with the accompanying
drawings.
[0012] FIG. 1 is a schematic of a production system in which
cogeneration of steam and hydrogen enables steam assisted recovery
of in situ upgraded hydrocarbons, according to one embodiment of
the invention.
[0013] FIG. 2 is a schematic of a production system illustrating
cogeneration of steam and hydrogen combined with a wellbore heater
and optional catalyst for use in steam assisted recovery of in situ
upgraded hydrocarbons, according to one embodiment of the
invention.
[0014] FIG. 3 is a graph of modeled results for hydrogen and carbon
monoxide levels in product gas from a direct steam generator versus
oxygen to fuel equivalence ratio for combustion in the direct steam
generator, according to one embodiment of the invention.
DETAILED DESCRIPTION
[0015] Turning now to the detailed description of the preferred
arrangement or arrangements of the present invention, it should be
understood that the inventive features and concepts may be
manifested in other arrangements and that the scope of the
invention is not limited to the embodiments described or
illustrated. The scope of the invention is intended only to be
limited by the scope of the claims that follow.
[0016] Embodiments of the invention relate to recovery of in situ
upgraded hydrocarbons by injecting steam and hydrogen into a
reservoir containing the hydrocarbons. A mixture output generated
as water is vaporized by direct contact with flow from fuel-rich
combustion provides the steam and hydrogen. The steam heats the
hydrocarbons facilitating flow of the hydrocarbons and reaction of
the hydrogen with the hydrocarbons to enable hydroprocessing prior
to recovery of the hydrocarbons to surface.
[0017] FIG. 1 illustrates a production system with a fuel-rich
direct steam generator 100 coupled to supply a fluid stream to an
injection well 101. The fluid stream includes steam and hydrogen
(H.sub.2) produced by the generator 100. In operation, heat
transfer from the steam makes petroleum products mobile enough to
enable or facilitate both upgrading by reaction of the petroleum
products with the hydrogen and recovery of the petroleum products
with, for example, a production well 102.
[0018] In some embodiments, the injection and production wells 101,
102 traverse through an earth formation 103 containing the
petroleum products, such as heavy oil or bitumen, heated by the
fluid stream. 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. Further, upgrading processes described herein may rely on
other production techniques, such as use of the fluid stream from
the generator 100 as a drive fluid or cyclic injecting and
producing during alternating periods of time.
[0019] The generator 100 includes a fuel input 104, an oxidant
input 106 and a water input 108 that are coupled to respective
sources of fuel, oxidant and water and are all in fluid
communication with a flow path through the generator 100. The
generator 100 differs from indirect-fired boilers since transfer of
heat produced from combustion occurs by direct contact of the water
with combustion gasses. This direct contact avoids thermal
inefficiency due to heat transfer resistance across boiler tubes.
Tubing 112 conveys the fluid stream from the generator 100 to the
injection well 101 by coupling an output from the flow path through
the generator 100 with the injection well 101.
[0020] Examples of the oxidant include air, oxygen enriched air and
oxygen (i.e., oxy combustion with greater than 95% pure O.sub.2 or
greater than 99% pure O.sub.2), which may be separated from air.
Sources for the fuel include natural gas or other hydrocarbon gas
mixtures that may contain at least 90% methane. As explained
further herein, at least some of the hydrogen in the fluid stream
comes from operation of the generator 100 with the fuel introduced
in excess of a supply rate that achieves complete combustion given
amount of oxygen supplied to the generator 100.
[0021] Such fuel-rich operating conditions of the generator 100
thus provide combustion at an oxygen:fuel equivalence ratio less
than 1. The oxidant:fuel equivalence ratio as used herein refers to
a ratio of actual oxidant:fuel ratio to a stoichiometric
oxidant:fuel ratio. A stoichiometric mixture contains just enough
of the oxygen for complete burning of the fuel such that all the
oxygen is consumed in reaction without the oxygen passing through
in combustion products.
[0022] The generator 100 produces the hydrogen at a pressure and
temperature suitable for reservoir injection conditions. Producing
the hydrogen mixed with the steam within the fluid stream from the
generator 100 therefore avoids alternative surface storage of
hydrogen or separate hydrogen production and injection equipment.
This cogeneration of the hydrogen and the steam together within the
generator 100 also enables injection of the hydrogen while limiting
safety issues associated with handling of the hydrogen. Compared to
in situ combustion for generation of the hydrogen, the hydrogen
being part of the fluid stream from the generator 100 further
enables delivery of the hydrogen through the conduit 112 and the
injection well 101 to locations where desired in the formation
103.
[0023] During operation, the steam upon exiting the injection well
101 and passing into the formation 103 condenses and contacts the
petroleum products to create a mixture of condensate from the steam
and the petroleum products. The mixture migrates through the
formation 103 due to gravity drainage and is gathered at the
production well 102 through which the mixture is recovered to
surface. A separation process may divide the mixture into
components for recycling of recovered water back to the generator
100.
[0024] Mobility provided by heat transfer from the steam to the
petroleum products makes the petroleum products available to mix
with the hydrogen to achieve the hydroprocessing. Depending on
factors such as temperature, exemplary reactions for the
hydroprocessing include desulfurization, olefin and aromatic
saturation and hydrocracking With respect to the saturation of
olefins, unsaturated bonds accept the hydrogen becoming capped to
prevent undesired polymerization of the petroleum products. At
least a few of the reactions may proceed to some extent even below
an injection temperature that the fluid stream produced by the
generator 100 enters the formation 103.
[0025] FIG. 2 shows a device 200 for cogeneration of steam and
hydrogen, an injector 201 and a recovery assembly including a
producer 202 all configured to function as described with respect
to FIG. 1. In addition, a wellbore heater 250 and optional catalyst
252 facilitate in situ upgrading of hydrocarbons by hydroprocessing
reactions. Disposing the heater 250 and the catalyst 252 along the
producer 202 places the catalyst 252 in a flow path of the
hydrocarbons from the formation 103 to the surface. The heater 250
also thereby increases temperature of the hydrocarbons in contact
with the catalyst 252 to a reaction temperature sufficient to
achieve the hydroprocessing reactions.
[0026] The hydrogen required for the reactions comes from the
hydrogen that is introduced through the injector 201. Proximity of
the producer 202 and the injector 201 allows for mixing of the
hydrogen with surrounding fluids at hydroprocessing zones where the
temperature is increased by the heater 250 to promote the
reactions. Flow of production fluids including the hydrocarbons and
water further mix with the hydrogen and help in transporting the
hydrogen toward the hydroprocessing zones.
[0027] In some embodiments, the heater 250 achieves subsurface
heating of the hydrocarbons to the reaction temperature above
300.degree. C. or above 400.degree. C. The heater 250 supplements
the heating of the hydrocarbons achieved by the fluid stream that
is produced by the generator 200 since the reaction temperature may
be above an injection temperature that the fluid stream enters the
formation 103. For some embodiments, the heater 250 provides a
non-steam based source of heat using various other techniques for
heating of the hydrocarbons.
[0028] Examples of the heater 250 include an induction heating
tool, a radio frequency or microwave heating device or a resistive
heating element. The heater 250 utilizing an exemplary induction
heating method includes a coiled conductive metal through which
current is passed to create heat by inducing hysteresis losses in a
metal liner of the producer 202. In this example of the heater 250,
current also passes into the reservoir surrounding the producer 202
for additional heating of the hydroprocessing zones.
[0029] Several approaches enable disposing of the catalyst 252
subsurface for the in situ upgrading. For example, passing the
catalyst 252 through the producer 202 to where desired may be done
as part of a water-in-oil emulsion or to create a packed bed. In
some embodiments, solid particles forming the catalyst 252 provide
packing in an annulus of the producer 202.
[0030] For some embodiments, the catalyst 252 defines a
hydroprocessing catalyst. Selection of the catalyst 252 depends on
poisoning susceptibility by sulfur species, water oxidation and
nitrogen in order to account for conditions that lead to transition
metal catalyst poisoning. Suitable compounds for the catalyst 252
include metal sulfides (e.g., MoS.sub.2, WS.sub.2, CoMoS and
NiMoS), metal carbides (MoC and WC) or other refractory type metal
compounds such as metal phosphides and metal borides.
[0031] In some embodiments, a water-gas shift reaction produces
additional hydrogen to supplement hydrogen production within
generators described herein. The water-gas shift reaction yields
carbon dioxide and the hydrogen by conversion of water vapor and
carbon monoxide also output in fluid streams from the generators.
In some embodiments, the water-gas shift reaction occurs once the
carbon monoxide is injected into a hydrocarbon reservoir.
[0032] The catalyst 252 as shown in FIG. 2 may thus define a
water-gas shift catalyst in a flow path of the carbon monoxide
mixed with the steam. In some embodiments, composition of the
catalyst 252 promotes both the hydroprocessing and water-gas shift
reactions or may include compounds that are mixed together or
disposed in separate locations and define the hydroprocessing
catalyst that is different from the water-gas shift catalyst.
Exemplary catalysts 252 specific for the water-gas shift reaction
include copper/zinc/aluminum (Cr/Zn/Al) and iron/chromium/copper
(Fe/Cr/Cu).
[0033] The upgrading of the hydrocarbons yields products with
permanent viscosity reduction. This viscosity reduction helps to at
least limit amount of diluting required for transport of the
products. In addition, the upgrading facilitates further processing
of the products at refineries.
[0034] FIG. 3 illustrates a plot of modeled results for hydrogen
and carbon monoxide levels in product gas from a direct steam
generator versus oxygen to fuel equivalence ratio for combustion in
the direct steam generator. First line 301 with triangular data
points represents the hydrogen levels. The generator produces over
19 volume percent hydrogen on a dry basis at an oxygen:fuel
equivalence ratio of 0.9. By contrast, conventional operation with
an oxygen:fuel equivalence ratio greater than 1 yields less than 1
volume percent hydrogen on a dry basis. While the oxygen:fuel
equivalence ratio of 0.9 is a minimum depicted, the generator may
operate at lower values of the oxygen:fuel equivalence ratio and
hence may produce even higher concentrations of the hydrogen than
indicated by the plot.
[0035] However, the steam produced per unit of the fuel burned
decreases as the oxygen:fuel equivalence ratio drops. For example,
the oxygen:fuel equivalence ratio of 0.9 provides about 86-88% of
the steam per unit of the fuel burned relative to operating at
stochiometric conditions (i.e., the oxygen:fuel equivalence ratio
equals 1). Selection of the oxygen:fuel equivalence ratio thus
depends on an economic balance between steam production rate and
hydrogen production rate.
[0036] Second line 302 with square data points represents the
carbon monoxide levels. The carbon monoxide level increases with
the hydrogen level as the oxygen:fuel equivalence ratio decreases.
Therefore, increase in the carbon monoxide available for the
water-gas shift reaction to make additional hydrogen occurs in a
synergistic relation with raising of the hydrogen output based on
the oxygen:fuel equivalence ratio. The generator produces over 12
volume percent carbon monoxide on a dry basis at the oxygen:fuel
equivalence ratio of 0.9. In contrast, conventional operation with
the oxygen:fuel equivalence ratio greater than 1 yields less than 1
volume percent carbon monoxide on a dry basis.
[0037] For some embodiments, fluid streams produced by generators
described herein contains at least 5 volume percent hydrogen on a
dry basis, at least 10 volume percent hydrogen on a dry basis or at
least 15 volume percent hydrogen on a dry basis. Operation with the
oxygen:fuel equivalence ratio less than 0.98, less than 0.95, less
than 0.92 or less than 0.9 may provide desired amounts of the
hydrogen within the fluid streams. While limited by reduction in
the steam production, ability to approach full hydrocarbon
upgrading relies on utilizing concentrations of the hydrogen as
high as possible.
[0038] In closing, it should be noted that the discussion of any
reference is not an admission that it is prior art to the present
invention, especially any reference that may have a publication
date after the priority date of this application. At the same time,
each and every claim below is hereby incorporated into this
detailed description or specification as additional embodiments of
the present invention.
[0039] Although the systems and processes described herein have
been described in detail, it should be understood that various
changes, substitutions, and alterations can be made without
departing from the spirit and scope of the invention as defined by
the following claims. 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 while the description,
abstract and drawings are not to be used to limit the scope of the
invention. The invention is specifically intended to be as broad as
the claims below and their equivalents.
* * * * *