SYSTEMS FOR USING GAS TO LIQUIDS TECHNOLOGY

RELATED APPLICATIONS

[0001] This application claims the benefit of, and priority to, U.S. Provisional

Application No. 61/844,279, filed July 9, 2013, entitled "Methods of Extracting Flowable Oil From Tar Sands," which is incorporated herein by reference in its entirety.

BACKGROUND

[0002] Gas to liquids (GTL) refers generally to processes by which coal, natural gas, and biomass are converted into valuable liquid fuels and chemicals. These processes are well established, and typically include gasification; syngas (synthesis gas) processing; Fischer- Tropsch synthesis; and syncrude (synthetic crude) refining and upgrading (see, e.g., wp. auburn.edu/eden/wp-content/up loads/2012/03/4470-Lecture-6-2013.pptx).

[0003] We have determined that output from GTL systems can be used for a variety of applications within the oil industry. The present invention relates to new ways of using GTL technology for oil extraction, transportation, processing, and/or refining.

SUMMARY

[0004] In one aspect, the invention provides a method of using output from a gas to liquids (GTL) plant for processing bitumen from oil sands, wherein the GTL output comprises at least one of a Fischer-Tropsch liquid fuel (FTL) to be used as a diluent for bitumen, water used to produce steam for extracting bitumen from the oil sands, process heat used to heat water to produce steam for extracting the bitumen from the oil sands, and shorter chain hydrocarbons ("short-ends" or "light ends") used to produce energy for extracting the bitumen from the oil sands.

[0005] In some embodiments, the GTL plant uses natural gas a feedstock. The natural gas feedstock may be from a geological source local to the GTL plant, and in some embodiments may comprise stranded gas. In other embodiments, the natural gas feedstock may comprise pipeline gas.

[0006] In some embodiments, the FTL may be used to reduce the viscosity of the bitumen for removing water associated with extracting the bitumen from the oil sands. The GTL plant may be located proximal to the site where the bitumen is extracted, or the GTL plant may be remote and the FTL is shipped to the site where the bitumen is extracted.

[0007] In some embodiments, the FTL is added to the bitumen to form a bitumen blend having a viscosity that is reduced relative to the bitumen alone and that meets a predetermined standard for shipping. The GTL plant may be located proximal to the site where the FTL is added to the bitumen, or the GTL plant may be remote and the FTL is shipped to a separate site where it is added to the bitumen. In some embodiments, the bitumen blend may be shipped by pipeline. In some embodiments, bitumen blend shipped by pipeline has a viscosity, for example, of about 350 centistokes at 11 °C. In other embodiments the bitumen may be shipped by rail tank car or tanker truck.

[0008] In certain preferred embodiments, the GTL output is used to support steam assisted gravity drainage (SAGD), and the GTL plant is located proximal to a SAGD facility. The GTL output may comprise water used to produce steam for extracting the bitumen from the oil sands using SAGD, process heat used to heat water to produce steam for extracting the bitumen from the oil sands using SAGD, and/or short chain hydrocarbons used to produce energy for extracting the bitumen from the oil sands using SAGD. In alternative embodiments, the GTL plant may be remote and the GTL output (e.g., short chain

hydrocarbons used to power SAGD generators) may be shipped to the SAGD facility.

[0009] In related aspect, the invention provides a bitumen blend comprising bitumen and a diluent comprising a Fischer-Tropsch liquid fuel (FTL), the bitumen and the FTL combined in proportions such that the resulting blend has a viscosity that meets a

predetermined standard for shipping.

[0010] In another related aspect, the invention provides a combined GTL-SAGD system for processing bitumen from oil sands, comprising a GTL plant and a SAGD facility located proximal to one another, wherein at least one output from the GTL plant is used as an input resource for SAGD, and wherein the at least one GTL output comprises at least one of water used to produce steam for extracting bitumen from oil sands, process heat used to heat water to produce steam for extracting the bitumen from the oil sands, and short chain hydrocarbons used to produce energy for extracting the bitumen from the oil sands. In some embodiments, the GTL plant and the SAGD facility are located at the same site. In alternative embodiments, the GTL plant and the SAGD facility are located at separate sites less than about 50 miles from one another.

[0011] Additional features and advantages of the present invention are described further below. This summary section is meant merely to illustrate certain features of the invention, and is not meant to limit the scope of the invention in any way. The failure to discuss a specific feature or embodiment of the invention, or the inclusion of one or more features in this summary section, should not be construed to limit the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The foregoing summary, as well as the following detailed description of the preferred embodiments of the application, will be better understood when read in conjunction with the appended drawings. For the purposes of illustrating the systems and methods of the present application, there are shown in the drawings exemplary embodiments. It should be understood, however, that the application is not limited to the precise arrangements and instrumentalities shown. In the drawings:

[0013] FIG. 1 shows a flowchart illustrating how syngas is converted into various liquid fuels (wp. auburn.edu/eden/wp-content/uploads/2012/03/4470-Lecture-6-20 13.pptx).

[0014] FIG. 2 shows an exemplary small-scale gas to liquids (GTL) system from

Velocys (www.velocys.com/stills/velocys_035.jpg).

[0015] FIG. 3 shows an exemplary schematic of bitumen extraction via steam assisted gravity drainage (SAGD) (www.connacheroil.com/en images/operations/sagd2011.gif).

DETAILED DESCRIPTION

[0016] In GTL, feedstock (natural gas, or lower-quality feedstocks such as coal or biomass) is converted into various synthetic liquid fuels. Typical GTL processes include gasification; syngas processing; Fischer-Tropsch (or other) synthesis; and syncrude refining and upgrading (see, e.g., wp.auburn.edu/eden/wp-content/uploads/2012/03/4470-Lecture-6 - 2013. pptx; all references cited herein are hereby incorporated by reference in their entirety). Natural gas gasification uses steam reforming (CH ₄ + H ₂ 0→ CO + 3H ₂ ) and/or partial oxidation (CH ₄ + ½0 ₂ → CO + 2H ₂ ) to convert methane to syngas (mixture of CO and H ₂ ) having an H ₂ :CO ratio of about 1.7-3. Coal and biomass gasification produce syngas with lower H ₂ :CO ratios (less than 1). Coal gasification also yields sulfur-containing impurities. Biomass gasification yields sulfur and nitrogen impurities, and includes complications of high moisture levels and fibrous mass resistant to size reduction. Syngas processing can remove impurities and moisture, and adjust the H ₂ :CO ratio via the water gas shift reaction: CO + H ₂ 0 ^ C0 ₂ + H ₂ .

[0017] As shown in FIG. 1, syngas can then be converted to liquid hydrocarbons via

Fischer-Tropsch synthesis (en.wikipedia.org/wiki/Fischer%E2%80%93Tropsch_process), methanol synthesis, higher alcohol synthesis, methanol to gas (MTG) process

(en.wikipedia.org/wiki/Gas_to_liquids), MTBE (methyl tert-butyl ether) synthesis, or other processes such as syngas to gasoline plus (en.wikipedia.org/wiki/Syngas_to_gasoline_plus). Fischer-Tropsch synthesis can be conducted at low or high temperature. Low-temperature Fischer-Tropsch (LTFT) typically uses a cobalt catalyst (particularly preferred when the feedstock is natural gas) and yields diesel and wax. High-temperature Fischer-Tropsch (HTFT) typically uses an iron catalyst, and yields gasoline and light olefins.

[0018] Large-scale commercial GTL facilities include Shell's Pearl GTL plant in

Qatar (www. shell. com.qa/en/products-services/pearl.html) and Sasol's South African Energy Cluster (www.sasol.com/about-sasol/south-african-energy-cluster/saso l-synfuels/operations- sasol-synfuels).

[0019] More recently, significant research and development and engineering efforts have been directed toward the development of mini- or micro-GTL technology, for processing less than or equal to about 10,000 barrels per day (bpd). Smaller-scale GTL plants are receiving increased interest and support, and are particularly well-suited for accessing landfill gas as well as "stranded gas" located in areas where it is not possible and/or economical to build a pipeline (www.forbes orn/sites/peterdetwiler/2014/03/28/small-gas-to-liquids-plan ts- get-a-huge-boost/). Leaders in this field include CompactGTL (www.compactgtl.com/), Velocys (www.velocys.com/index.php), and Greyrock Energy (www.greyrock.com/). Each of these companies has built facilities, and output from these facilities has been tested by ConocoPhiUips (Houston, TX) and deemed to be of high quality. Brazilian energy company Petrobras (www.petrobras.com/en/home.htm) has installed and tested units from

CompactGTL and Velocys for over three years, and has approved both for industrial quality and reliability. CompactGTL has received an order from Kazakhstan for its first commercial unit (www. compactgtl. com/ compactgtl-announces-3 OOO-bpd-commercial-gtl-proj ect-in- kazakhstan/), configured to produce approximately 3,000 bpd of synthetic diesel. Velocys has also has a project of similar scale (www.velocys.com/arcv/financial/fa/ocgfa20130923.php).

[0020] The viability of producing liquid fuels using GTL technology is established.

Exemplary GTL systems and methods are described in detail by the above-mentioned companies, both in diagrams published on their websites (see above) and in their patents and patent applications (see, e.g., U.S. Patent Nos. 8,753,589, 8,444,939, 8,431,095, 8,173,083, 8,118,889, and 8,021,633, assigned to CompactGTL; and U.S. Patent Nos. 8,460,411, 8,450,381, 8,100,996, and 7,829,602, assigned to Velocys). FIG. 2 shows an exemplary small-scale GTL system from Velocys (www.velocys.com/stills/velocys_035.jpg). The present invention provides, in various embodiments, systems and methods to harness existing GTL technology, particularly small-scale GTL systems, for additional uses not previously described. [0021] In some embodiments, the present invention provides systems and methods for using the synthetic fuel output of GTL systems (e.g., a Fischer-Tropsch synthesis-derived liquid fuel, also referred to as FTL) as diluent for bitumen from tar sands.

[0022] Tar sands (also referred to as oil sands) are a combination of clay, sand, water, and bitumen, which can be extracted and refined into oil (ostseis.anl.gov/guide/tarsands/). Much of the world's oil (more than 2 trillion barrels) is in the form of tar sands. Tar sands deposits near the surface can be recovered by open pit mining. The mined tar sands are transported to an extraction plant, where a hot water process (using either naphthenic or paraffinic solvent) separates the bitumen from sand, water, and minerals. The bitumen is then transported and eventually upgraded into synthetic crude oil (SCO). For reserves that are too deep for mining, in-situ production methods, such as steam assisted gravity drainage (SAGD) and cyclic steam stimulation (CSS) are used. In northern Alberta, Canada, for example, it is estimated that 80% of the oil sands are recoverable through in-situ production, with only 20% recoverable by mining (www.energy.alberta.ca/OilSands/1715.asp). Recovery rate percentages vary depending on the method of extraction, and are estimated approximately as follows: 5-10% for primary recovery of conventional oil; up to 20% using conventional enhanced oil recovery methods such as water flood or polymer flood; up to 35-40%) bitumen using CSS; up to 50-60%> of bitumen using SAGD; and up to 90%> of bitumen from mining.

[0023] Increasingly, tar sands oil resources are being considered as an alternative to conventional oil. However, oil refineries are designed for light crudes (density less than 950 kg/m ³ ) (www.ualberta.ca/~gray/Links%o20&%o20Docs/Web%)20Upgradi ng%)20Tutorial.pdf). Bitumen, also known as asphalt, and sometimes referred to as "tar" or "pitch," is a thick, sticky, black form of petroleum. Bitumen has a density over 1000 kg/m ³ , contains over 4% sulfur, and has a viscosity approximately 1,000 times that of light crude oil. The World Energy Council (WEC) defines natural bitumen as oil having a viscosity greater than 10,000 centipoise under reservoir conditions and an API (American Petroleum Institute) gravity of less than 10 °API (www.worldenergy.org/documents/ser_2010_report_l .pdf). Thus, bitumen requires additional treatment before it can be sold to / used by most refineries.

[0024] Mined bitumen is typically upgraded to synthetic crude oil (SCO) (see, e.g., www.ualberta.ca/~gray/Links%20&%20Docs/Web%20Upgrading%2 0Tutorial.pdf and www.albertacanada.com/mexico/documents/P7_Processing_Upgradi ng_and_Refining_HOL A2013_KCY.pdf). Up to half of the bitumen can be recovered by vacuum distillation.

Upgrading focuses on the resulting residue, which is a complex mixture of chemical species that are too heavy to distill (e.g., boiling point greater than 524 °C, molecular weight greater than 400). Upgrading uses a combination of processes including: improving the carbon to hydrogen ratio (removing carbon by thermal cracking, delayed coking, fluid coking, etc. or adding hydrogen by hydroconversion / hydroprocessing, hydrocracking, etc.); converting heavy boiling material into lighter material (cracking larger molecules into smaller ones and fractioning based on boiling range); hydrotreating to remove sulfur and nitrogen; and blending fractions into SCO, before further refining into finished products such as gasoline, diesel fuel, jet fuel, etc.

[0025] Bitumen from in-situ production is typically used to form a bitumen blend

(www. albertacanada. com/mexico/ documents/P7_Processing_Upgrading_and_Refining_HOL A2013_KCY.pdf and onlinepubs.trb.org/onlinepubs/dilbit/Dettmanl02312.pdf). Primary treating of SAGD bitumen mainly consists of oil/water separating. Water and sediment is removed, then diluent may be added to reduce oil viscosity so the remaining produced water can be removed. Water and sediment / solids cause internal corrosion in pipelines, and are limited by some companies to less than 0.5% by volume for the oil to be considered

"transmission grade" (onlinepubs.trb.org/onlinepubs/Dilbit/Ironside072312.pdf). As described above, bitumen is so viscous that it does not flow. Therefore, after water and solids are removed, the bitumen must be diluted to lower the density and viscosity to predetermined specifications so that it can be transported. For example, to increase pumping capacity, many companies require viscosity of 350 centistokes at 11 °C and density of 19 °API for shipping by pipelines (geoscan.ess.nrcan.gc.ca/text/geoscan fulltext/NCUT2009_Paper28.pdf and enbridge.com/DeliveringEnergy/Shippers/CrudeOilCharacteristi cs.aspx). When the density of the diluent included in the blend is less than 800 kg/m ³ , the diluent is typically natural gas condensate (NGC), particularly the naphtha component, and the blend is referred to as dilbit. When the density of the diluent is greater than 800 kg/m ³ , the diluent is typically synthetic crude and the blend is referred to as synbit (en.wikipedia.org/wiki/Dilbit). Dilbit generally comprises a natural gas condensate that is about 62 °API, less than 0.1 % by weight sulfur, and 0.6 centistokes viscosity at 40 °C. Synbit generally comprises fully upgraded SCO that is about 34 °API, less than 0.1 % by weight sulfur, and 3 centistokes viscosity at 40 °C

(www.digitalrefining.com article/1000607,Has_

l_and_bitumen_arrived_.html#.U6M9_PldXng). Diluted bitumen (dilbit or synbit) can be transported (e.g., by railcar, tanker truck, or pipeline) for upgrading / refining.

[0026] Effective bitumen diluents (e.g., C5) exist, but their increased use has significantly increased their price (see, e.g., en.wikipedia.org/wiki/Natural_gas_condensate). Demand is projected to rise sharply and exceed the available supply, necessitating high-cost import of diluent by pipeline or rail (see, e.g., business.financialpost.com/2013/05/23/diluent- shortages-could-make-for-sticky-situation-for-alberta-bitume n/? lsa=3063 -0262 and www.coqa-inc.org/Segato0608.pdf).

[0027] In addition, existing diluents do not make good feedstock for refineries. For example, as dilbit contains hydrocarbons at extreme ends of the viscosity range, it can be more difficult to process than typical crude oil (en.wikipedia.org/wiki/Dilbit). As a consequence, most refineries strip the diluent out of the dilbit (e.g., by distillation) and recycle it. Thus, the diluent is transported from the site of manufacture to the site of extraction (or close thereto), blended into the bitumen, shipped as a constituent component of the dilbit, stripped from the dilbit, and transported back to the blending facility (see, e.g.,

www.osrin.ualberta.ca/en/Resources/DidYouKnow/2012/August /DiluentandDilbit.aspx and kitimatclean.ca/category/press-release/). The cycle is repeated, and is highly inefficient and costly (see, e.g., openparliament.ca/committees/natural-resources/41-2/21/micha el-priaro- 1/only/); its only function is make the bitumen fluid enough to meet transport regulations.

[0028] The present invention overcomes the problems of conventional diluents such as condensate, providing systems and methods for cooperative diluent production and bitumen blending in which FTL from a GTL plant (preferably using natural gas as a feedstock, various examples of which are known and are commercially available, as described above) is advantageously used as a diluent for oil from tar sand (either pre- or post- extraction), so that the viscosity of the oil from tar sand is decreased and it can be extracted, transported, treated, refined, etc. The natural gas may come from a variety of sources, including local geological sources of natural gas (whether stranded or not; sometimes available from the same locations and/or formations as the bitumen to be diluted) as well as remotely located natural gas received by pipeline. In certain preferred embodiments, the GTL plant is integrated with (co-located with or located in close proximity to) the site of blending, providing on-site production of diluent. This approach provides several advantages. For example, if diluent is produced at or adjacent to the site of blending, no inbound logistics are required. If diluent is produced near to, but not at, the site of blending, then logistics are simplified to the extent that the distance between these two loci is shortened. Locally- produced FTL diluent lowers logistical costs, uses freely available feedstock that would otherwise be unused, and lowers capital and operating expenses. Notwithstanding the above, in alternative embodiments, FTL from GTL systems located remotely may be transported to the site of extraction / blending and advantageously used as diluent. Supply (production) of the blended product is less secure if the source of diluent is remote, and subject to interruption by weather or other causes. However, there is no limitation on the distance between the GTL facility and the extraction / blending facility; distance affects the economy and logistics of the combined system, but not the technical viability.

[0029] The present invention also comprises systems and methods for using other outputs of GTL systems (heat, water, etc.) as resources for oil extraction or other industries. For example, in some embodiments of the invention, output from the GTL plant is used for extracting bitumen from oil sands using a thermal in-situ method such as, but not limited to, SAGD. In certain preferred embodiments of the invention, the GTL plant is integrated with (co-located with or located in close proximity to) a SAGD facility. In SAGD, two parallel horizontal oil wells are drilled one above the other; the upper well injects steam, and the lower well collects the heated crude oil or bitumen that flows out of the formation, along with any water from the condensation of injected steam (see, e.g., en.wikipedia.org/wiki/Steam- assisted_gravity_drainage and www.conocophillips.ca/technology-and- innovation/unconventional/Pages/sagd.aspx). FIG. 3 shows an exemplary schematic of bitumen extraction via SAGD (www.connacheroil.com/en/images/operations/sagd201 l .gif). SAGD uses large amounts of water and energy (for heating and pumping). The water is often fresh, surface water. Sediment from aquifers would damage SAGD facilities and is removed via high-cost pretreatment. In various embodiments of the present invention, water from the GTL system is advantageously used for SAGD processes. Water to feed integrated SAGD facilities can come from both the Fischer-Tropsch process, which produces water (see, e.g., wp. auburn.edu/eden/wp-content/uploads/2012/03/4470-Lecture-6-20 13.pptx and

www.netl.doe.gov/research coa energy-systems/gasification/gasifipedia/ftsynthesis), and stripping water out of the gas supply. This GTL-derived water is "greywater," but is substantially free of silicates, so there is no need to filter it (e.g., to prevent sand clogs) before it is converted to steam. As much as 50% of water required for SAGD can come from these sources, thereby lowering the aquifer depletion that is currently associated with SAGD. In addition, cost of steam generation is a major part of the cost of oil production, and historically natural gas has been used as a fuel (en.wikipedia.org/wiki/Steam-assisted_gravity_drainage). The Fischer-Tropsch process is highly exothermic, or heat generating (see, e.g.,

www.velocys.com/our_products_processes_ft.php, www.netl.doe.gov/research/coal/energy- systems/ gasification/ gasifipedia/ ftsynthesis, www.pinetwork.org/whatsnew/brophy_ 10.pdf, www.oxfordcatalysts.com press/wp/wpl 10224_microchannel_FT_white_paper_24Febl 1.pdf) . The average heat released per -CH ₂ - formed is about 145 kJ (see, e.g., U.S. Patent No. 8,278,363). In some systems and methods of the present invention, heat from the exothermic Fischer-Tropsch process is advantageously used to pre-heat, or heat, the water to produce steam for SAGD. Thus, emissions to the environment from SAGD can be significantly lowered. In still further embodiments, shorter-chain hydrocarbons ("short-ends" or "light ends"), which are byproducts of GTL production using the Fischer-Tropsch process (see, e.g., wp. auburn.edu/eden/wp-content/uploads/2012/03/4470-Lecture-6-20 13.pptx, www.fischer- tropsch.org/DOE/DOE_reports/88014638/wax-sctl2.pdf, and

www.netl.doe.gov/research coa energy-systems/gasification gasifipedia/ftsynthesis) and are not as high in energy as FTL, can be burned as a source of electricity used to power one or more generators in a SAGD facility. In alternative embodiments, GTL outputs (water, heat, short-ends, etc.) can also be used for other related or unrelated industrial processes.

[0030] As described above, the GTL facility is preferably fully integrated with

(distance on the order of feet) or located in close proximity to (distance less than about 50 miles, preferably about 30 km or less) the SAGD site, providing a variety of advantages including, but not limited to, efficiencies of scale in site preparation, staffing, staffing accommodations, etc. and/or in shared resources such as use of electricity (whether generated on-site or utility-provided power). However, in alternative embodiments, the distance between these facilities in the combined system may be greater. For example, improvements to insulation in the pipes connecting the two facilities may in time enable water of high temperature to be sent over a longer distance.

[0031] While there have been shown and described fundamental novel features of the invention as applied to the preferred and exemplary embodiments thereof, it will be understood that omissions and substitutions and changes in the form and details of the disclosed invention may be made by those skilled in the art without departing from the spirit of the invention. Moreover, as is readily apparent, numerous modifications and changes may readily occur to those skilled in the art. Hence, it is not desired to limit the invention to the exact construction and operation shown and described and, accordingly, all suitable modification equivalents may be resorted to falling within the scope of the invention as claimed. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.