Note: Descriptions are shown in the official language in which they were submitted.
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INTEGRATED XTL AND IN-SITU OIL SANDS EXTRACTION
PROCESSES
FIELD OF THE INVENTION
[0001] The invention relates to integration of processes for producing
hydrocarbon products. More particularly, the invention relates to integration
of
an XTL process for producing hydrocarbons with an in-situ oil sands extraction
process and/or a bitumen treatment/upgrading process. The integration includes
one or more of steam integration, process water integration, water treatment
system integration, nitrogen integration, and integrated use of carbon-
containing
products or by-products from one process in another process.
BACKGROUND
[0002] In-situ oil sands extraction processes are used for extracting highly
viscous oil products such as heavy crude oil and/or bitumen from underground
oil
sands reservoirs. There are several variations of these processes, and they
typically involve the continuous injection of large amounts of high pressure
steam and/or hydrocarbon solvents into the reservoir to reduce the viscosity
of
the oil product, allowing it to be pumped to the surface. An example of such a
process is SAGD (steam-assisted gravity drainage) in which steam is injected
into the reservoir. Some process variations utilize steam in combination with
a
hydrocarbon solvent such as LPG (liquefied petroleum gas) to improve recovery
from the SAGD process, and these process variations may generally be referred
to as SA-SAGD (solvent-assisted SAGD). The hydrocarbon solvent is soluble in
bitumen at reservoir conditions and decreases bitumen viscosity, and may
increase the production rate over a solely SAGD process. Still other process
variations use only a hydrocarbon solvent such as propane only and may be
generally referred to as HABR (hydrocarbon-assisted bitumen recovery).
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[0003] Once the oil product is pumped to the surface it undergoes various
processing and/or upgrading steps in a plant. For example, in SAGD processes
for recovering bitumen, sand and water are removed from the product in a SAGD
plant and a diluent is added to the bitumen to enable it to be transported by
pipeline. The bitumen may undergo further processing on-site, for example to
convert it to SCO (synthetic crude oil). In SA-SAGD and HABR, at least some of
the solvent is recovered from the oil product as part of the upgrading
process.
After upgrading, one or more product streams from the upgraded oil product are
transported via pipeline to another location, such as a remotely located oil
refinery.
[0004] As will be appreciated, in-situ oil sands extraction is performed in
remote areas. Large amounts of energy are consumed in producing high
pressure steam for in-situ oil sands extraction, and large amounts of fresh
water
are also required to generate steam for SAGD and SA-SAGD processes. Also, the
diluents, solvents and other inputs required for extraction and for viscosity
reduction, dilution and/or upgrading the recovered product are typically
transported across great distances to the extraction site. In addition, the
transport of certain carbonaceous by-products of the bitumen upgrading
processes to off-site locations may not be practical or economically feasible.
Therefore, these by-products, which include asphaltene and coke, are either
stockpiled or disposed of.
[0005] The acronym XTL ("X"-to-liquid) is used to describe a group of
processes by which various carbon-containing materials are converted to
hydrocarbon products such as LPG, naphtha and diesel. XTL processes may
produce significant quantities of pressurized steam as a by-product.
[0006] The carbonaceous feed material of the XTL process can include coal,
coke (also referred to as "pet coke"), biomass, natural gas or any combination
of
these. Where natural gas is used as the feed material, the process may be
referred to as GTL (gas-to-liquid). The XTL process includes a first step in
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whichthe feed material is converted to a syngas comprising carbon monoxide and
= hydrogen, a second step whereby the syngas is converted to the liquid
hydrocarbon product(s) by a F-T (Fischer-Tropsch) process, and a third step
whereby the FT liquid product is converted to saleable hydrocarbon products
like
diesel. It will be appreciated that this description of XTL is oversimplified
and
that the syngas generation and the F-T process steps may themselves include
multiple steps. Some of these additional steps are described in the detailed
description which follows below.
[0007] The inventors are not aware of any successful integration of XTL
processes with in-situ oil sands extraction and/or bitumen treatment/upgrading
processes, despite the fact that sources of XTL feed materials such as natural
gas
reservoirs are often located in close proximity to oil sands reservoirs, and
despite
the fact that products or by-products of one process can be utilized in a
different
process.
SUMMARY
[0008] In an embodiment, there is provided an integrated process for
producing at least two hydrocarbon product streams. The integrated process
comprises: (a) converting a carbon-containing feed stream to a first
hydrocarbon product stream by an XTL process, wherein steam is produced by
said XTL process; (b) diverting at least a portion of the steam produced by
said
XTL process to an in-situ extraction process for extracting an oil product
from an
oil sands reservoir; (c) extracting said oil product from the oil sands
reservoir by
said in-situ extraction process; and (d) converting said oil product to a
second
hydrocarbon product stream.
[0009] In an embodiment, the XTL process may comprise the steps of: (i)
converting a carbon-containing feed stream to a syngas comprising carbon
monoxide and hydrogen; (ii) cooling said syngas with boiling feed water (BFW),
whereby said syngas cooling converts at least a portion of said BFW to a first
portion of said steam produced by said XTL process; (iii) converting at least
a
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portion of said syngas to a first hydrocarbon product stream by a Fischer-
Tropsch
= (F-T) process, wherein said F-T process produces a second portion of said
steam
produced by said XTL process.
[0010] In an embodiment, the in-situ extraction process comprises steam-
assisted gravity drainage (SAGD); solvent-assisted SAGD (SA-SAGD) or
hydrocarbon-assisted bitumen recovery (HABR).
[0011] In an embodiment, the carbon-containing feed stream comprises
natural gas, a carbon-containing by-product from said step of converting said
oil
product to a second hydrocarbon product, or a mixture thereof.
[0012] In an embodiment, the carbon-containing feed stream is converted
to said syngas by a reforming, gasification or co-gasification reaction.
[0013] In an embodiment, the first hydrocarbon product stream comprises
one or more of liquefied petroleum gas (LPG), diesel and naphtha.
[0014] In an embodiment, the oil product is bitumen or heavy crude oil,
and at least a portion of said steam diverted to said SAGD process is injected
into said oil sands reservoir to assist in recovery of said oil product from
said
reservoir.
[0015] In an embodiment, the in-situ extraction process is a SAGD or SA-
SAGD process, and wherein at least a portion of said steam diverted to said
SAGD process is injected into said oil sands reservoir.
[0016] In an embodiment, a steam generation unit generates additional
steam which is injected into the reservoir.
[0017] In an embodiment, at least a portion of said steam raised from the
XTL process is used to generate power for both the in-situ extraction and XTL
processes.
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, [0018] In an embodiment, at
least a portion of said steam diverted to said 5
= in-situ extraction process is used to heat solvent for
the in-situ extraction
process.
[0019] In an embodiment, the oil product comprises
bitumen and the
integrated process further comprises diluting said bitumen with a sufficient
amount of a diluent such that the diluted bitumen is transportable by a
pipeline;
and wherein the diluent comprises naphtha produced by said XTL process.
[0020] In an embodiment, the oil product comprises
bitumen, and said step
of converting said oil product to a second hydrocarbon product comprises a
bitumen upgrading process, and wherein the carbon-containing by-product of
said bitumen upgrading process comprises coke or asphaltene.
[0021] In an embodiment, the first hydrocarbon
product stream comprises
liquefied petroleum gas (LPG), naphtha and diesel, and wherein at least a
portion
of the LPG and/or the naphtha is diverted to said in-situ extraction process
and is
injected into said oil sands reservoir to reduce viscosity of said oil product
while
it is present in said reservoir.
[0022] In an embodiment, the process further
comprises separation of air
into an oxygen stream and a nitrogen stream, wherein the oxygen stream is
reacted with said carbon-containing feed stream in the conversion of the
carbon-
containing feed stream to said syngas. The nitrogen stream may be used for
providing an inert atmosphere in process equipment used in said XTL process,
said in-situ extraction process, and/or the conversion of said oil product to
said
second hydrocarbon product stream.
[0023] In an embodiment, the )01 process and the in-
situ extraction
process are co-located in close proximity to one another.
[0024] In an embodiment, an integrated system is
provided for producing
at least two hydrocarbon product streams. The system comprises: (a) a syngas
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generation unit for converting a carbon-containing feed stream to a syngas
= comprising carbon monoxide and hydrogen; (b) a Fischer-Tropsch (F-T) unit
for
converting at least a portion of said syngas to a first hydrocarbon product
stream, wherein said F-T unit may convert said syngas to a F-T product, and
the
system may further comprise a F-T product upgrading unit to hydrocrack the FT
product to produce said first hydrocarbon product stream; (c) a steam
generation unit for supplying pressurized steam to an in-situ extraction
process
for extracting an oil product from an oil sands reservoir; and (d) a syngas
steam
conduit for transporting steam from said syngas generation unit to said in-
situ
extraction process.
[0025] In an embodiment, the system further comprises a F-T steam
conduit for transporting steam from said F-T unit to said in-situ extraction
process.
[0026] In an embodiment, the integrated further comprises a well located
in an oil sands reservoir, wherein said steam supply means comprises a steam
source and a steam conduit connecting said steam source to said well.
[0027] In an embodiment, the steam generation unit generates steam from
combustion of natural gas.
[0028] In an embodiment, the syngas generation unit comprises a steam
reformer, a gasification unit or a co-gasification unit.
[0029] In an embodiment, the first hydrocarbon product stream comprises
liquefied petroleum gas (LPG), diesel, naphtha, or combinations of any two or
more thereof.
[0030] In an embodiment, the system further comprises an F-T product
upgrading unit in which a product from the F-T unit is converted to said first
hydrocarbon product stream.
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[0031] In an embodiment, the system further comprises an air separation
- unit for separating oxygen from air, wherein the oxygen stream is reacted
with
said carbon-containing feed stream in the syngas generation unit.
[0032] In an embodiment, the system further comprises a bitumen
recovery unit in which bitumen recovered from said in-situ extraction process
is
diluted with naphtha produced by said XTL process, and wherein a conduit for
transporting naphtha extends from the XTL process to a bitumen recovery unit.
[0033] In an embodiment, the oil product comprises bitumen, and wherein
said system further comprises a bitumen treatment/upgrading unit which
produces coke or asphaltene as a by-product.
[0034] In an embodiment, at least a portion of the coke or asphaltene by-
product is optionally incorporated into the carbon-containing feed stream.
[0035] In an embodiment, the by-product is coke, and said system further
comprises a wet mill in which said coke is combined with process water to form
aqueous coke slurry.
[0036] In an embodiment, the system further comprises a conduit for
transporting said aqueous coke slurry to said syngas generation unit.
[0037] In an embodiment, the first hydrocarbon product stream comprises
liquefied propane gas (LPG), naphtha and/or diesel, and wherein the system
further comprises solvent make-up conduit for transporting said LPG and/or
naphth to said in-situ extraction process.
[0038] In an embodiment, the solvent make-up conduit delivers the solvent
to a mixing station where the solvent is mixed with pressurized steam.
[0039] In an embodiment, the system further comprises an integrated
water treatment system which receives process water from the XTL process and
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the in-situ extraction process, wherein the integrated water treatment system
= includes a single water treatment unit to treat said process water.
[0040] In an embodiment, the XTL process and the in-situ extraction
process are co-located in close proximity to one another.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described, by way of example only, with reference to
the attached drawings, in which:
[0041] Figure 1 illustrates an integrated process and system for production
of first and second hydrocarbon product streams according to a first
embodiment
of the invention;
[0042] Figure 2 illustrates an integrated process and system for production
of first and second hydrocarbon product streams according to a second
embodiment of the invention;
[0043] Figure 3 illustrates an integrated process and system for production
of first and second hydrocarbon product streams according to a third
embodiment of the invention;
[0044] Figure 4 illustrates an integrated process and system for production
of first and second hydrocarbon product streams according to a fourth
embodiment of the invention;
[0045] Figure 5 illustrates an integrated process and system for production
of first and second hydrocarbon product streams according to a fifth
embodiment
of the invention;
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[0046] Figure 6 illustrates an integrated process and system for production
= of first and second hydrocarbon product streams according to a sixth
embodiment of the invention; and
[0047] Figure 7 illustrates an integrated process and system for production
of first and second hydrocarbon product streams according to a seventh
embodiment of the invention.
DETAILED DESCRIPTION
[0048] The following is a detailed description of various embodiments of
the invention, each of which integrates an XTL process and an in-situ oil
sands
extraction process for recovering bitumen or heavy crude oil. Where the oil
product is bitumen, there may also be integration of the XTL process with one
or
more bitumen treatment/upgrading steps. In each embodiment, the integration
includes one or more of steam integration, process water integration, water
treatment system integration, nitrogen integration, and integrated use of
carbon-
containing products or by-products from one process in another. In the
embodiments described herein, the plants for performing the XTL process and,
where applicable, the bitumen upgrading process, are co-located with or in
close
proximity to the reservoir from which the bitumen is extracted by SAGD, SA-
SAGD or HABR.
[0049] Unless indicated otherwise below, conduits and components shown
in dashed lines (except for the boxes labelled "XTL", "In-Situ Oil Sands" and
"Bitumen Processing") are to be understood as being optional.
[0050] Figure 1 illustrates an integrated process and system 100 for
production of first (XTL) and second (in-situ extraction) hydrocarbon product
streams according to a first embodiment of the invention. In system 100, the
first hydrocarbon product stream comprises one or more XTL products which are
produced from a carbon-containing feed stream in the XTL process. In this
embodiment, the carbon-containing feed stream comprises natural gas obtained
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from a natural gas source 12 such as a natural gas reservoir. The natural gas
is
transported from source 12 through conduit 14 to a syngas generation unit 16
where it is converted to a synthesis gas (hereinafter referred to as
"syngas").
[0051] The term "syngas" as used herein refers to a gas mixture containing
varying amounts of carbon monoxide and hydrogen. A syngas may be produced
by steam reforming, partial oxidation, and/or autothermal reforming,
separately
or in combination, of natural gas; by gasification/co-gasification of a solid
or
liquid carbonaceous material; or any combinations of these gaseous, liquid and
solid materials. The reforming/gasification reaction consumes water (as steam)
and/or oxygen.
[0052] The syngas generation unit 16 in the first embodiment may
comprise a reforming unit wherein natural gas (predominantly methane) is
converted to syngas by one or more steps, with inputs of steam and molecular
oxygen. As shown in Figure 1, the oxygen input is provided by an air
separation
unit (ASU) 18 which separates oxygen from air, and steam is provided by a
steam and condensate system 19, which is further described below. Hydrogen
for natural gas desulfurization is provided by a hydrogen separation unit 20
which may separate a portion of the hydrogen from the syngas. Figure 1 shows
an oxygen conduit 62 extending from ASU 18 to syngas generation unit 16, a
steam conduit 64 between the steam and condensate system 19 and syngas
generation unit 16, and a hydrogen conduit 66 between the hydrogen separation
unit 20 and syngas generation unit 16.
[0053] The overall syngas generation reaction is exothermic and is cooled
by water, more specifically by boiling feed water (BFW) fed to the syngas
generation unit 16 through BFW conduit 68. The BFW is heated by the syngas to
generate steam which may be at high pressure, typically about 70-120 bar, and
high temperature. Steam and liquid waste water are removed from the syngas
generation unit 16 through one or more conduits, shown in Figure 1 as syngas
unit process water conduit 22 and syngas unit steam conduit 24.
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[0054] The syngas is transported from syngas generation unit 16 to an F-T
= unit 26 through syngas conduit 28. In the F-T unit 26 the syngas
undergoes an
F-T reaction whereby the syngas is catalytically converted to a hydrocarbon
product stream, typically a mixture of liquid and/or gaseous hydrocarbons.
Steam and liquid water are by-products of the F-T process, and are removed
from the F-T unit 26 through one or more conduits, shown in Figure 1 as F-T
unit
process water conduit 32 and F-T unit steam conduit 34. It can be seen that
the
process water from syngas generation unit 16 and F-T unit 26 is fed to water
treatment unit 46 through process water conduit 70 in which the water is
treated
to produce BFW.
[0055] The composition of the hydrocarbon product stream produced by F-
T unit 26 is variable, and depends at least partly on the F-T reaction
temperature, the reaction pressure, the type of catalyst (typically cobalt- or
iron-
based), and the composition of the syngas. The specific F-T process shown in
Figure 1 favours synthesis of long-chain hydrocarbons, and the XTL process
includes the step of converting the long-chain hydrocarbons to shorter-chain
hydrocarbon products in an F-T product upgrading unit 30, which receives the F-
T product through conduit 72. The shorter-chain hydrocarbons may be
separated into different fractions to provide two or more hydrocarbon products
such as liquefied petroleum gas (LPG), diesel and naphtha. For example, proper
hydrocracking of the FT product can yield winter diesel fuel with the required
specification for arctic conditions. The hydrocarbon products produced by the
F-
T upgrading unit 30 are referred to herein as the "first hydrocarbon product
stream".
[0056] As shown in Figure 1, the ASU 18, syngas generation unit 16,
hydrogen separation unit 20, F-T unit 26 and F-T product upgrading unit 30 are
all included within the box labelled "XTL", indicating that the reactions
conducted
in these reaction units are part of the overall XTL process.
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, [0057] Turning now to the
in-situ oil sands extraction process, Figure 1 12
= illustrates the process steps and the system components
involved in extracting a
highly viscous oil product, such as heavy crude oil or bitumen, from an oil
sands
reservoir 36 using a SAGD or SA-SAGD process. In a typical SAGD process, a
pair of horizontal wells is drilled in the oil sands reservoir, with one well
located
above the other. High pressure steam is injected into the bore of the upper
well
to heat the oil sands and reduce the viscosity of the oil product contained
therein. The heated oil product drains into the bore of the lower well, and
from
there it is pumped to the surface for processing. SAGD typically requires
about
2-5 barrels of water-equivalent steam to produce one barrel of bitumen or oil.
In
SA-SAGD, a combination of hydrocarbon solvent and high pressure steam are
injected together into the reservoir 36.
[0058] System 100 requires one or more sources of
pressurized steam for
injection into the reservoir 36. As shown in Figure 1, steam for the
extraction
process is supplied by the steam and condensate system 19 through steam
conduit 74. Asmentioned above, the steam and condensation unit 19 receives
the pressurized steam by-product from the syngas generation unit 16 and the F-
T unit 26. Steam may also be supplied to reservoir 36 from an optional steam
generation unit 38 through steam conduit 76. The steam generation unit 38 may
comprise a once through steam generator (OTSG) in which boiler feed water is
converted to steam by combustion of natural gas and/or off-gases recovered
from the XTL process and/or bitumen recovery. These off gases contain
combustible species such as C1-C4 hydrocarbons, CO and H2.
[0059] The steam generation unit 38 receives
natural gas from a natural
gas source such as a natural gas reservoir, which may be the same or different
from the natural gas source 12 supplying the syngas generation unit 16. In
Figure 1 the same natural gas source 12 supplies natural gas to both the
syngas
generation unit 16 and the steam generation unit 38, and the natural gas is
transported from source 12 through conduit 42 to the steam generation unit 38.
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[0060] It can be seen that Figure 1 also includes an auxiliary boiler 31
which may be regarded as belonging to the XTL process, and which is primarily
used during start-up of the XTL process, for example to drive the ASU 18
turbine. Like the optional steam generation unit 38, the auxiliary boiler 31
generates pressurized steam from BFW received from water treatment unit 46
through BFW conduit 78, using heat from the combustion of natural gas obtained
from the natural gas source 12, and optionally from off gases recovered from
the
XTL process and/or bitumen recovery. Figure 1 shows a conduit 80for feeding
natural gas (from source 12) and off-gas (from bitumen recovery unit 44) to
the
auxiliary boiler 31. The steam produced by auxiliary boiler 31 is fed to the
steam
and condensate system 19 through steam conduit 82. The presence of auxiliary
boiler 31 may reduce the size requirements of steam generation unit 38 in the
in-situ extraction process, or may altogether eliminate the need for steam
generation unit 38. For this reason, the box representing steam generation
unit
38 in Figure 1 is shown in dashed lines.
[0061] As shown in Figure 1, the steam and condensate system 19 also
provides steam to, and receives condensate from, a power generation unit 33
through respective conduits 84 and 86, wherein the power generation unit 33
produces power for the in-situ extraction and XTL processes.
[0062] Where the in-situ extraction process comprises SAGD, steam from
the steam and condensate system 19 and optionally from the steam generation
unit 38 is injected directly into the reservoir 36. However, where the in-situ
extraction process comprises SA-SAGD, the steam is first fed to a mixing
station
35 where it is combined with a solvent prior to injection into reservoir 36.
It will
be appreciated that the output from OTSG 38 is typically 70-80% quality steam
and the remainder is liquid water. The OTSG steam output is dewatered before
injecting to the reservoir and the water is sent to water treatment (not shown
in
the drawings).
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[0063] In Figure 1 the oil product produced by SAGD or SA-SAGD is
= bitumen. Following extraction of bitumen from the oil sands reservoir 36,
sand,
water and optionally solvent are separated from the bitumen, for example in
the
bitumen recovery unit 44. In Figure 1 the bitumen recovery step is considered
part of the overall in-situ extraction process. The water from bitumen
recovery
is transported to water treatment unit 46. To reduce the viscosity of the
bitumen
to a sufficient level that it can be transported by a pipeline, a diluent is
added to
the bitumen. In the process and system of Figure 1, the diluent comprises
naphtha produced by the XTL process. The diluted bitumen product is referred
to as "Dilbit" in Figure 1. The use of naphtha produced by the XTL process co-
located with the SAGD process saves considerable costs in transporting naphtha
to the SAGD process location.
[0064] Where the in-situ extraction process comprises SA-SAGD, the LPG
produced by the XTL process may be used as a solvent which is combined with
steam at the mixing station 35. Optionally, as shown in Figure 1, the LPG may
enter the solvent make-up stream 88 where it may be combined with recovered
solvent flowing through conduit 90 from the bitumen recovery unit 44 before
being transferred to mixing station 35. Optionally, a portion of the naphtha
from
the XTL process may also enter the solvent make-up stream 88 through conduit
92, to be mixed with steam at the mixing station 35, and injected into the
reservoir 36 to assist in the extraction process.
[0065] As mentioned above, steam and water are by-products of both
steps of the XTL process, i.e. the syngas generation process and the F-T
process.
The condensed water (process water) by-products from the syngas generation
process and the F-T process enter the integrated water treatment system shown
in Figure 1 through conduits 22 and 32, leading to water treatment unit 46
through process water conduit 94, where it is treated in water treatment unit
46. However, these two process water streams 22 and 32 are not of the same
quality. The water separated from the syngas stream is usually clean water
which can be sent directly to a demineralization unit (DM) to produce BFW.
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However, the process water from the F-T unit 26 is contaminated with organic
= acids and alcohols and typically requires biological treatment.
[0066] Process water separated from the bitumen in the bitumen recovery
unit 44 is sent to the water treatment unit 46 through water conduit 96 for
treatment. Therefore, it can be seen that the water treatment unit 46, serves
both the XTL process and the in-situ oil extraction process. The integration
of
the water treatment saves costs due to the fact that one water treatment unit
46
serves both processes.
[0067] In addition, the amount of water processed by the water treatment
unit 46 may be less than the amount which would be processed if the two
processes were operated separately. In this regard, the XTL process is a net
producer of water, and SAGD or SA-SAGD consumes water. Thus, integration of
water treatment saves energy in that less water needs to be treated,
eliminates
the need to import fresh water, and also saves capital costs in that a single
water
treatment unit serves both the XTL and in-situ oil extraction processes.
[0068] With regard to the steam by-products of the syngas generation unit
16 and the F-T unit 26, the steam conduits 24 and 34 transfer the steam to the
SAGD or SA-SAGD process, ASU unit 18, and power generation unit 33 through
the steam and condensate system 19, in which steam is conditioned, separated
from condensate, and distributed to users. As shown in Figure 1, the steam and
condensate system 19 may also provide steam and receive condensate from
steam condensation at a number of steps in the process. Although not shown in
the drawings, the steam from steam and condensate unit 19 could be utilized in
the water treatment unit 46 where evaporative water treatment is used.
[0069] The steam produced by syngas cooling in the syngas generation unit
16 is a high pressure (HP) steam (about 70-120 bar) which, along with the F-T
steam from the F-T unit 26, is sent to the steam and condensate system 19.
From the steam and condensate unit, the HP steam may be directly used in the
SAGD or SA-SAGD process. However, all or part of the HP steam may be sent to
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the ASU 18 through steam conduit 98 to drive the extraction turbine (not shown
in Figure 1), and the resulting intermediate pressure (IP) steam may be
extracted from the steam extraction turbine and then, along with the turbine
condensate, is sent to steam and condensate system 19 through conduit 102.
[0070] On the other hand, steam produced by the F-T unit 26 may not be
directly usable in the SAGD or SA-SAGD process. In this regard, F-T steam
generated by a low temperature F-T process has a pressure of about 10-20 bar
which is not suitable for SAGD or SA-SAGD application and may instead be used
for power generation or process heating. The power generated by the F-T
steam may be consumed in both the XTL and in-situ oil extraction processes.
However, where a high temperature F-T process is conducted in the F-T unit,
the
F-T steam could be used in the SAGD or SA-SAGD process.
[0071] Thus, it can be seen from Figure 1 that the steam by-products of
the XTL process enter the steam supply system of the SAGD process.
Integration of the steam systems has several benefits, including reduced fresh
water input to the SAGD process, lower SAGD steam generation costs, and
reducing the amount of water which must be treated.
[0072] Further integration of the processes is possible. For example, as
noted above, the air separation unit 18 separates oxygen from air. The air
separation unit produces a nitrogen fraction which can be used for providing
an
inert atmosphere in one or more process vessels in the integrated system 100,
for example to purge a system for routine maintenance procedures. This
reduces the amount of nitrogen which must be transported to the site from a
remote location.
[0073] Figure 2 illustrates an integrated process and system 200 for
production of first and second hydrocarbon product streams according to a
second embodiment of the invention. Integrated system 200 includes many of
the same elements as integrated system 100, and like reference numerals are
used to show like elements of systems 100 and 200.
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[0074] It can be seen that system 200 shares many elements with system
= 100, and includes the production of a first hydrocarbon product stream by
an XTL
process and a second hydrocarbon stream by an in-situ oil sands extraction
process which, as in Figure 1, may comprise SAGD or SA-SAGD. The primary
difference between systems 100 and 200 is that system 200 includes a bitumen
upgrading process conducted in bitumen upgrading unit 52. The presence of a
bitumen upgrading process and unit in system 200 allows for additional process
integration.
[0075] The bitumen upgrading unit 52 receives bitumen, which may be
diluted with naphtha, through conduit 104 from the bitumen recovery unit 44 of
the in-situ extraction process. Unit 52 converts the bitumen to synthetic
crude
oil (SCO) which may be transported to another location for further processing,
typically by pipeline. The bitumen upgrading process increases the relatively
low
H:C ratio of the bitumen by a process referred to as "coke rejection". The
coke
by-product generated by bitumen upgrading is typically considered a waste
product which is stockpiled or landfilled. However, in the integrated process
and
system 200 according to Figure 2, the coke is incorporated into the carbon-
containing feed stream which is fed to the syngas generation unit 16 of the
XTL
process through conduit 106, either on its own or in combination with natural
gas. In this regard, the natural gas conduit 14 is shown in dotted lines in
Figure
2 to show that natural gas is optionally not included in the carbon-containing
feed stream containing coke. It will be appreciated that the syngas generation
unit 16 of this embodiment may include both a reforming unit to convert
natural
gas to syngas and a gasification unit in order to convert the coke to syngas.
The
co-gasification of carbon- containing materials in one unit could also be
considered.
[0076] The coke is fed to the syngas generation unit 16 through conduit
106 as aqueous slurry. The slurry may be prepared by combining process water
with the coke in a wet mill 54, and feeding the slurry to the syngas
generation
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18
unit 16 where it is gasified or co-gasified (where natural gas is present),
and
- converted to syngas by reaction with steam and oxygen.
[0077] System 200 also includes an acid removal unit 108 which removes
carbon dioxide and sulfur from the syngas produced by unit 16. Figure 2 shows
that the carbon dioxide is exhausted, however, it is possible to achieve
further
integration by using this carbon dioxide in the in-situ extraction process. In
this
regard, the carbon dioxide produced by the acid removal unit may be
transferred
through a conduit (not shown) from the acid removal unit to the mixing station
35, where it is combined with steam, and optionally with LPG and/or naphtha.
The presence of carbon dioxide in the steam which is injected into reservoir
36
can have a positive effect on bitumen recovery.
[0078] Figure 3 illustrates an integrated process and system 300 for
production of first and second hydrocarbon product streams according to a
third
embodiment of the invention. Integrated system 300 includes many of the same
elements as integrated systems 100 and 200, and like reference numerals are
used to show like elements of systems 100, 200 and 300.
[0079] System 300 also includes the production of a first hydrocarbon
product stream by an XTL process and a second hydrocarbon stream by an in-
situ oil sands extraction process which, as in Figures 1 and 2, may comprise
SAGD or SA-SAGD. The primary difference between systems 300 and 200 is that
system 300 uses a different type of bitumen upgrading process which leads to
process integration different from that of system 200.
[0080] Rather than upgrading bitumen by coke rejection, system 300
upgrades the bitumen by hydrogen addition in a bitumen upgrading unit 52.
Bitumen upgrading by hydrogen addition also increases the H:C ratio of the
bitumen and converts the bitumen to SCO. Because the bitumen upgrading
process of system 300 does not produce a carbon-containing by-product, the
carbon-containing feed stream in system 300 comprises natural gas, as in
system 100. However, system 300 produces additional process integration in
, a = CA 02806044 2013-02-13
i that a portion of the hydrogen separated from the syngas by
the hydrogen 19
= separation unit 20 is diverted through hydrogen conduit 56 and
is used in the
bitumen upgrading unit 52.
[0081] Figure 4 illustrates an integrated process and system
400 for
production of first and second hydrocarbon product streams according to a
fourth
embodiment of the invention. Integrated system 400 includes many of the same
elements as integrated systems 100, 200 and 300, and like reference numerals
are used to show like elements of systems 100, 200, 300 and 400.
[0082] System 400 also includes the production of a first
hydrocarbon
product stream by an XTL process and a second hydrocarbon stream by an in-
situ oil sands extraction process which, as in Figures 1 and 2, may comprise
SAGD or SA-SAGD. The primary difference between systems 400 and 100 is that
system 400 also includes a solvent deasphalting unit 58 in which asphaltene is
separated from diluted bitumen. The removal of the asphaltene fraction
decreases the viscosity of the bitumen. The deasphalted bitumen may be
transported off-site as dilbit or may be subjected to upgrading in a bitumen
upgrading unit, for example by hydrogen addition as in system 200, to produce
SCO. This variation is described below in connection with Figure 5.
Alternatively, the deasphalted bitumen may be thermally cracked in a cracking
unit (not shown) to produce SCO.
[0083] The separated asphaltene is incorporated into the
carbon-containing
feed stream through conduit 110 and is fed to the syngas generation unit 16,
either on its own or in combination with natural gas. As in Figure 2, the
natural
gas conduit 14 is shown in dotted lines in Figure 4 to show that natural gas
is
optionally not included in the carbon-containing feed stream to syngas unit
16.
[0084] Additional integration is provided by using a C5
hydrocarbon fraction
produced by FT upgrading unit 30, received through conduit 112, as solvent
make-up in the solvent deasphalting unit 58, and/or by using the off-gas from
CA 02806044 2013-02-13
20
the solvent deasphalting unit 58 through conduit 114, the off-gas which
contains
C1-C4 hydrocarbons, as a feed for the OTSG steam generation unit 38.
[0085] Figure 5 illustrates an integrated process and system 500 for
production of first and second hydrocarbon product streams according to a
fifth
embodiment of the invention. Integrated system 500 includes many of the same
elements as integrated systems 100 to 400, and like reference numerals are
used to show like elements of these systems.
[0086] System 500 also includes the production of a first hydrocarbon
product stream by an XTL process and a second hydrocarbon stream by an in-
situ oil sands extraction process which, as in Figures 1 to 4, may comprise
SAGD
or SA-SAGD. In particular, system 500 is substantially the same as system 400
except that the deasphalted bitumen produced by solvent deasphalting unit 58
is
subjected to a bitumen upgrading process by hydrogen addition in a bitumen
upgrading unit 52. This converts the deasphalted bitumen to SCO.
[0087] Figure 6 illustrates an integrated process and system 600 for
production of first and second hydrocarbon product streams according to a
sixth
embodiment of the invention. Integrated system 600 includes many of the same
elements as integrated systems 100 to 500, and like reference numerals are
used to show like elements of these systems.
[0088] System 600 also includes the production of a first hydrocarbon
product stream by an XTL process and a second hydrocarbon stream by an in-
situ oil sands extraction process which, as in Figures 1 to 5, may comprise
SAGD
or SA-SAGD. In particular, system 600 is substantially the same as system 100
of Figure 1, except that steam generator unit 38, which is an OTSG in Figures
1to 5, is replaced by a direct contact steam generator (DSG). A mixture of
steam and flue gas is produced in DSG 38 from combustion of natural gas and
off-gases in contact with process water contaminated with hydrocarbons, fed to
DSG by process water conduit 116. The presence of flue gas in the steam
CA 02806044 2013-02-13
21
injected into the well may enhance recovery of bitumen by the SAGD or SA-
SAGD process.
[0089] Figure 7 illustrates an integrated process and system 700 for
production of first and second hydrocarbon product streams according to a
seventh embodiment of the invention. Integrated system 700 includes many of
the same elements as integrated systems 100 to 600, and like reference
numerals are used to show like elements of these systems.
[0090] System 700 includes the production of a first hydrocarbon product
stream by an XTL process and a second hydrocarbon stream by an in-situ oil
sands extraction process which comprises HABR. The XTL process of system 700
is similar or identical to that described above with reference to systems 100-
600.
However, the in-situ oil sands extraction process of system 700 is
significantly
different from those described above in that it does not utilize steam for
injection
into the reservoir 36. Rather, in system 700, only solvent is injected into
the
reservoir 36 to extract the oil product.
[0091] Therefore, system 700 does not include a dedicated steam
generation unit for the in-situ oil sands extraction process, but rather
includes a
solvent heater 60 for heating the solvent from make-up stream 88 before it is
injected into the reservoir 36. While the extraction process of system 700
does
not include a steam generation unit, an auxiliary boiler 31 and a steam and
condensate system 19 are provided, at least in part for generating steam to be
fed to solvent heater 60 through steam conduit 118, to heat the solvent in
solvent heater 60 before it is injected into the reservoir 36. Condensate from
solvent heater 60 is returned to steam and condensate system 19 through
conduit 120.
[0092] As in the embodiments described above, the solvent which is
injected into the reservoir 36 in the HABR process of Figure 7 may comprise
LPG
and optionally naphtha from the XTL process, as well as solvent recovered from
the bitumen recovery unit 44.
, - , CA 02806044 2013-02-13
22
[0093] Although a number of the processes described above utilize natural
- gas as a feed material for the XTL process, either on its own or in
combination
with coke or asphaltene, it will be appreciated that the carbon-containing
feed
material can include other carbon sources, such as coal and/or biomass, either
in
addition to or instead of natural gas.
[0094] Although the word "conduit" is used in the above description to
describe means for transferring gases, liquids and solids between various
system
components, the use of the word "conduit" does not limit the means by which
gases, liquids and solids are transferred between system components. In some
cases, the conduits may be process piping, but this is not necessarily the
case.
For example, solids are generally transferred by means other than process
piping.
[0095] Furthermore, because the drawings illustrate the systems and
processes of the invention in a schematic manner, the routing of conduits, the
connections between two or more conduits, and the connections between the
conduits and system components, is not necessarily as shown in the drawings.
[0096] Although the invention has been described with reference to certain
specific embodiments, it is not limited thereto. Rather, the invention
includes all
embodiments which may fall within the scope of the following claims.
