Carbon isotope analysis of microbially produced methane after exogenous carbon addition to geological formations

Abstract

Techniques for distinguishing between biomethane and fossil methane using isotope analysis are described. Examples include the use of radioisotope analysis and stable isotope analysis to assess methane sources. In some cases, radioisotope analysis is used to calibrate stable isotope analysis techniques or to verify the accuracy or reliability of stable isotope analysis results.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of and priority to U.S. Provisional Application No. 63 / 426,026, filed November 16, 2022, which is incorporated herein by reference.

[0002]

[0002] The present invention is in the field of renewable natural gas. The present invention relates generally to subsurface biological methanogenesis and differentiation. [Background technology]

[0003]

[0003] The world's growing energy demand is creating unprecedented challenges for recovering energy resources and mitigating the environmental impacts of using those resources. Some argue that global production rates for oil and domestic natural gas will peak within the next decade. Once this peak is reached, primary recovery of oil and domestic natural gas will begin to decline as the most easily recoverable energy stocks begin to deplete. Historically, old oil fields and coal mines are abandoned once the easily recoverable materials have been extracted.

[0004] As global energy prices continue to rise, it may become economically viable to extract additional oil and coal from these formations using conventional drilling and mining techniques. However, there comes a point when more energy is required to recover the resource than can be obtained through recovery. At that point, conventional recovery mechanisms become uneconomical, regardless of the price of energy.

[0005]

[0005] Meanwhile, renewable energy sources are being developed and are beginning to become price-comparable to fossil energy sources. While renewable energy sources are useful as alternatives to fossil fuel energy, energy distribution infrastructure (e.g., pipelines, etc.) is already in place to transport / deliver fossil hydrocarbon fuels, so it is desirable to produce renewable fuels such as biomethane that can use the existing infrastructure. While various processes exist for producing renewable fuels, further advances are still needed. Summary of the Invention [Means for solving the problem]

[0006]

[0006] Provided herein are methods, systems, and techniques for producing renewable fuels, such as biomethane, and analyzing the produced fuel to determine the amount of produced fuel corresponding to the renewable fuel produced. The methods, systems, and techniques described herein include those in which renewable methane (biomethane) is produced in a geological formation by a consortium of symbiotic methanogenic microorganisms that anaerobically digest an injected biogenic feedstock, such as waste glycerol, waste erythritol, waste sorbitol, or waste maltitol, or a liquid containing other waste products (e.g., wastewater, a carbonaceous material source, etc.), and the produced biomethane is extracted from the formation as produced methane or natural gas and subjected to analysis to determine the amount (e.g., fraction) of methane or natural gas that is biogenic, i.e., produced from the biogenic feedstock by the consortium of symbiotic methanogenic microorganisms. In an example, the analysis can include isotope analysis, such as stable isotope analysis and / or radioisotope analysis. Radioisotope analysis can be used to establish baseline amounts of biogenic methane or natural gas and can be used in parallel with stable isotope analysis to verify or calibrate the stable isotope analysis for later use.

[0007] Advantageously, in examples, the methods described herein are useful for generating and evaluating methane extracted from geological formations such as oil field reservoirs, such as for determining the amount of methane produced from reservoirs that are biogenic in origin. Many or most oil field reservoirs, even depleted oil field reservoirs, contain existing hydrocarbons, including methane that is exclusively fossil in origin. It will be appreciated that many oil field reservoirs are located deep below the Earth's surface, such as at depths where the reservoir does not interact with the surface or is completely or substantially isolated or confined from the surface, groundwater, or other aquifers that interact with the surface, and therefore contain little, if any, biogenic carbon and substantially only fossil carbon that may be derived from larger hydrocarbons (e.g., oil) present in the reservoir. In examples, such oil field reservoirs are useful as sites for anaerobic digestion of feedstocks by a consortium of microorganisms to produce methane or other gaseous products. Such generated methane mixes with existing methane in the reservoir; therefore, methane produced from the reservoir may be a combination of the original fossil methane and methane produced by anaerobic digestion of the feedstock. If the feedstock is a biogenic or renewable feedstock, the methane produced by anaerobic digestion corresponds to biogenic or renewable methane. When the goal is to convert subsurface renewable carbon-containing feedstocks to renewable methane, it may be desirable to use feedstocks that have a much higher thermodynamic likelihood of being converted to methane than the fossil carbon present in the reservoir. Nevertheless, in some instances, stimulating natural microbial consortia by introducing labile feedstocks may stimulate them to metabolize natural fossil hydrocarbons into methane. Therefore, it may be useful to distinguish renewable carbon from fossil carbon in methane, and the methods, systems, and techniques disclosed herein provide such a distinction.

[0008]

[0008] The techniques described herein provide for the generation and characterization of produced methane by isotopic analysis techniques, such as stable isotope analysis and radioisotope analysis, to determine the amount or fraction of produced methane produced by anaerobic digestion that corresponds to renewable methane. Advantageously, the disclosed techniques allow for evaluation using stable isotope analysis, which can be faster and more efficient than radioisotope analysis. The described techniques are useful for, e.g. 13 C signature, 14 C signature, or 13 C and 14 This allows for characterization of methane based on its isotopic signature, such as a combination of both C and C. Furthermore, the described technique allows for characterization of the amount of gaseous product produced by anaerobic digestion of a feedstock that is biogenic in origin, without any type of isotopic labeling of the feedstock and / or enrichment of the feedstock with one or more isotopes. In other words, the described technique can use feedstocks that contain natural isotopic abundances, such as when no artificial alteration of the isotopic composition in the feedstock is used.

[0009] In one aspect, a method for producing and analyzing a fluid is disclosed. An exemplary method of this aspect includes injecting a feedstock (e.g., a waste stream, a biogenic feedstock, etc.) into a geological formation, the formation including a consortium of symbiotic microorganisms, the consortium of symbiotic microorganisms at least partially anaerobically digesting the feedstock, such as a feedstock containing a known amount or fraction of a radioisotope, to produce gaseous products; producing a fluid from the formation, the fluid including the gaseous products and optionally other gases, such as Ar or N2; and performing radioisotope analysis of at least a portion of the fluid, such as the gaseous portion, using the known amount or fraction of the radioisotope to identify the amount or fraction of the gaseous products in the fluid derived from the feedstock. In this manner, the radioisotope analysis can be used to establish the amount or relative amount or fraction of the gaseous products in a fluid that is biogenic in origin. In some examples, the radioisotope is 14C. In some examples, the gaseous products include CH4, CO2, H2, or any combination thereof. In examples, the disclosed technology can use the isotopic signature of methane as a fingerprint to determine the origin (biogenic or fossil) of the methane. Optionally, the method of this embodiment can include establishing a consortium of microorganisms in the formation, such as by providing a microbial inoculum in the formation.

[0010] In some examples, the feedstock includes waste glycerol, waste erythritol, waste sorbitol, waste maltitol, wastewater, waste products, carbonaceous material sources, etc. Waste products that can be used in some embodiments of the present technology can be derived from any number of sources that produce wastewater, effluent streams, waste products, or organic waste with carbonaceous material content and can be consumed by microorganisms in a geological environment. As an example, a waste product or carbonaceous material source can include biodiesel wastewater or agricultural wastewater, although the present technology can use wastewater or waste streams, all of which can be encompassed as waste products containing carbonaceous material from a wide variety of sources. The present technology can utilize any type of waste product, including developed waste streams in which waste materials are mixed or solubilized in water, or effluent waste streams produced from one or more other activities. In some examples, the waste stream or feedstock can contain carbonaceous material derived from a single source or various sources or mixtures of various sources, such as carbonaceous material derived from one or more biogenic or renewable carbon sources or other sources. Advantageously, the techniques described herein are useful for determining the amount or fraction of gaseous products produced from the processing of feedstocks that are biogenic or renewable in origin, regardless of the source of the feedstock.

[0011]

[0011] By way of non-limiting example, the technology may be used to treat one or more waste product streams including waste from agriculture, horticulture, aquaculture, forestry, hunting or fishing; waste from the preparation and processing of meat, fish, dairy or other foods of animal origin, for example effluent streams from slaughterhouses or commercial food manufacturing; waste from the preparation and processing of fruit, vegetables, plants, cereals, edible oils, cocoa, coffee, tea or tobacco; conserve production, yeast and yeast extract production, molasses preparation and fermentation; waste from sugar processing; carbon-containing waste from refineries or other manufacturing plant processes; waste from the dairy industry such as whey; waste from the baking and confectionery industry; waste from the production or fermentation of alcoholic and non-alcoholic materials or beverages, including vinegar production; waste from wood processing and panel and furniture manufacturing; Waste from the manufacture and processing of pulp, paper, or cardboard; waste from the textile industry, which may contain grease, wax, or other materials; waste from the manufacture, formulation, supply, or use of basic organic chemicals, which may or may not contain glycerol or other alcohol residues (e.g., glycerol, erythritol, sorbitol, or maltitol); waste from the aerobic treatment of waste, such as the non-compostable fraction of municipal solid waste or similar waste; waste from the anaerobic treatment of waste, such as the liquid from the anaerobic treatment of municipal solid waste or similar waste; grease or oil mixtures from oil / water separations containing edible oils or fats; garden and park waste, such as cemetery waste; or any other waste, residue, or effluent generated during other material processing. In some cases, such waste product streams may be used alone or in combination with other waste streams.

[0012]

[0012] In some embodiments, waste products may include semi-solid waste products, including wet solids that may remain from filtration or as previously entrained solids, such as from food production. As a non-limiting example, vegan or vegetarian alternative products may be produced from processed feedstocks including nuts, soy, or plant materials, and the residual solids or semi-solid waste material or wet stream may be incorporated into a waste product stream for delivery to the geological environment. Additionally, waste product streams may be developed from renewable biomass products or waste products. As a non-limiting example, renewable biomass products may include materials or waste products from planted crops or crop residues, and may include all annual or perennial agricultural crops from existing agricultural land that can be used as feedstocks for renewable fuels, such as grains, oilseeds, or sugarcane, as well as energy crops such as switchgrass, prairie grass, duckweed, or other planted, pond-grown, or grown seeds. Similarly, crop residues can include biomass remaining from the harvesting or processing of planted crops from existing agricultural land, or any biomass removed from existing agricultural land to facilitate crop management, including biomass removed from agricultural land in connection with invasive species control or fire management, regardless of whether the biomass includes any part of the crop or crop plant. Renewable biomass can include planted trees or tree residues, including slash and any woody residue produced during the processing of planted trees from actively managed plantations for use in lumber, paper, furniture, or other uses. Renewable biomass can include slash and pre-commercial thinnings, biomass obtained from buildings or other areas regularly occupied by people or the immediate vicinity of public infrastructure at risk of wildfire, algae, and the materials or waste products identified above, including animal waste materials and animal by-products or separated yard waste or food waste, such as recycled cooking or trap grease, dairy and swine manure, landfill waste, wastewater or wastewater sludge, food waste, green waste, urban landscape waste, or other organic waste.

[0013] In some examples, waste streams used in the described techniques may include waste streams that are undesirable or unsuitable for use in other processes, such as due to the chemical makeup of the waste. In some examples, waste streams that are acidic may not be suitable for some processing applications, but may still be useful in the techniques described herein without increasing or altering the pH of the waste stream. In some examples, waste streams that are basic may not be suitable for some processing applications, but may still be useful in the techniques described herein without increasing or altering the pH of the waste stream. In some examples, waste streams containing excess solutes (e.g., salts) may not be suitable for some processing applications, but may still be useful in the techniques described herein without increasing or altering the amount of solutes (e.g., salinity) in the waste stream. As an example, a waste stream such as salted whey may contain excess salt beyond that desired for use in a particular application, but such a waste stream may still be useful as a feedstock with the disclosed methods and systems. For example, if the formation contains water with significant salt concentrations, the addition of a salt-containing waste stream may actually dilute the water present in the formation, while in other cases the formation water may be lean in salt compared to the salt-containing feedstock. In either case, the salt-containing waste stream may still be useful for the technology described herein, even if such waste stream is not useful for applications that are more sensitive to other salts.

[0014] In some examples, the method of this aspect can include, or further include, using the amount or fraction of gaseous products in the fluid derived from the feedstock to determine one or more stable isotope analysis calibration factors. For example, the one or more stable isotope analysis calibration factors can be used in subsequent analyses in the same or another geological formation to determine the amount or fraction of gaseous products in a produced fluid that is biogenic in origin using stable isotope analysis. In some examples, the one or more stable isotope analysis calibration factors include, are characteristic of, or are derived from one or more isotope fractionation factors.

[0015]

[0015] In one example, the method of this aspect may include, or further include, the steps of injecting a second feedstock into a second geological formation, the second formation including a second consortium of symbiotic microorganisms, and the second consortium of symbiotic microorganisms at least partially anaerobically digesting the second biogenic feedstock to produce gaseous products; producing a second fluid from the second geological formation, the second fluid including the gaseous products; and performing stable isotope analysis of the second fluid using one or more stable isotope analysis calibration coefficients to determine a second amount or fraction of the gaseous products in the second fluid derived from the second biogenic feedstock.

[0016]

[0016] In some cases, the second geological formation may be the same as or different from the geological formation. In some cases, the second consortium of symbiotic microorganisms may be the same as or different from the consortium of symbiotic microorganisms. In some cases, the second biogenic feedstock may be the same as or different from the feedstock. In some cases, the second fluid may be the same as or different from the fluid. Such a process may involve first using the geological formation to determine a stable isotope analysis calibration factor, and then using the stable isotope analysis calibration factor for processing and evaluation directly using stable isotope analysis. In some cases, the radioisotope analysis can be repeated one or more times, such as to verify or update the stable isotope analysis calibration factor. It may be desirable to repeat the radioisotope analysis, such as when the chemistry within the formation changes. For example, if the composition of the feedstock changes, it may be useful to re-determine the stable isotope analysis calibration factor. In another example, if the temperature within the formation changes or is identified, it may be useful to redetermine the stable isotope analysis calibration factor. In another example, if the composition of the microbial consortium changes or is identified, it may be useful to redetermine the stable isotope analysis calibration factor.

[0017] In some examples, determining one or more stable isotope analysis calibration factors using the amount or fraction of gaseous products in the fluid derived from the feedstock includes determining an isotopic distribution of stable isotopes in the feedstock, determining an isotopic distribution of stable isotopes in the gaseous products in the fluid, and determining one or more stable isotope analysis calibration factors using the isotopic distribution of stable isotopes in the biogenic feedstock, the isotopic distribution of stable isotopes in the gaseous products in the fluid, and the amount or fraction of gaseous products in the fluid derived from the feedstock. In examples, the stable isotopes in the feedstock include: 12 C or 13 C (and 1 H and 2 In the example, the stable isotopes contained in the gaseous product include: 12 C or13 C (and 1 H and 2 H) is included.

[0018] In some examples, the isotopic distribution of stable isotopes contained in one or more samples of fluid produced from the formation may be determined prior to injecting any biogenic feedstock, such as to obtain a baseline level. The isotopic distribution of stable isotopes contained in one or more samples of fluid produced from the formation may optionally be used to determine one or more stable isotope analysis calibration factors. In other examples, the isotopic distribution and / or baseline levels of gases present in the formation prior to injecting the biogenic feedstock are not determined. In some examples, samples of fluids produced from the formation may be obtained during or after injecting the biogenic feedstock (e.g., shortly thereafter, e.g., within one day). Optionally, such samples may be subjected to stable isotope analysis to determine baseline levels of gases present in the formation at or after injection of the biogenic feedstock.

[0019] Other methods of this aspect can bypass the use of radioisotope analysis and instead use one or more stable isotope analysis calibration factors in stable isotope analysis to produce and analyze the fluid. In some examples, the stable isotope analysis calibration factors can be determined using radioisotope analysis, as described above. An exemplary method of this aspect includes identifying one or more stable isotope analysis calibration factors; injecting a biogenic feedstock into a geological formation, the geological formation including a consortium of symbiotic microorganisms, the consortium of symbiotic microorganisms at least partially anaerobically digesting the biogenic feedstock to produce gaseous products; producing a fluid from the geological formation, the fluid including the gaseous products; and performing stable isotope analysis of at least a portion (e.g., a gas phase portion) of the fluid using the one or more stable isotope analysis calibration factors to determine the amount of gaseous products in the fluid derived from the biogenic feedstock. In some examples, the one or more stable isotope analytical calibration factors include, are characteristic of, or are derived from one or more isotope fractionation factors. Optionally, radioisotope analysis can be performed periodically or as needed to confirm, update, or obtain stable isotope analytical calibration factors or values ​​derived from stable isotope analytical calibration factors (e.g., isotope fractionation factors).

[0020]

[0020] In some examples, performing stable isotope analysis of at least a portion of the fluid includes determining an isotopic distribution of stable isotopes contained in the biogenic feedstock, determining an isotopic distribution of stable isotopes contained in gaseous products in the fluid, and determining the amount or fraction of gaseous products in the fluid derived from the biogenic feedstock using the isotopic distribution of stable isotopes contained in the biogenic feedstock, the isotopic distribution of stable isotopes contained in the gaseous products in the fluid, and one or more stable isotope analysis calibration factors.

[0021] In some examples, the isotopic distribution of stable isotopes in one or more samples of fluid produced from the formation may be determined prior to injecting any biogenic feedstock, such as to obtain a baseline level. The isotopic distribution of stable isotopes in one or more samples of fluid produced from the formation can optionally be used to determine the amount or fraction of gaseous products in the fluid derived from the biogenic feedstock.

[0022]

[0022] Optionally, identifying one or more stable isotope analytical calibration factors includes injecting a second biogenic feedstock into a second geological formation, the second formation including a second consortium of symbiotic microorganisms, the second consortium of symbiotic microorganisms at least partially anaerobically digesting the second biogenic feedstock to produce gaseous products, e.g., the second biogenic feedstock containing a known amount of radioisotope; producing a second fluid from the second geological formation, the second fluid including the gaseous products; and performing radioisotope analysis of the second fluid using the known amount of radioisotope to determine one or more stable isotope analytical calibration factors. Optionally, the second geological formation may be the same as or different from the geological formation. Optionally, the second consortium of symbiotic microorganisms may be the same as or different from the consortium of symbiotic microorganisms. In some cases, the second biogenic feedstock may be the same as or different from the biogenic feedstock. In some cases, the second fluid may be the same as or different from the fluid.

[0023] In another aspect, a system for producing and analyzing a fluid is disclosed. An exemplary system of this aspect includes one or more pumps in fluid communication with a geological formation including a consortium of symbiotic microorganisms, e.g., one or more pumps configured to inject a biogenic feedstock into the formation, where the consortium of symbiotic microorganisms at least partially anaerobically digest the biogenic feedstock to produce gaseous products, and produce a fluid from the formation, where the fluid includes the gaseous products. In some examples, the system of this aspect includes a geological formation including a consortium of symbiotic microorganisms. In some examples, a system of this aspect includes a computing device or processor in data communication with a non-transitory storage medium including executable instructions that, when executed by the computing device or processor, cause the computing device or processor to perform operations including identifying an isotopic distribution of stable isotopes and / or radioactive isotopes in the biogenic feedstock, identifying an isotopic distribution of stable isotopes and / or radioactive isotopes in the gaseous products in the fluid, and determining the amount or fraction of the gaseous products in the fluid derived from the biogenic feedstock using the isotopic distribution of stable isotopes and / or radioactive isotopes in the biogenic feedstock, the isotopic distribution of stable isotopes and / or radioactive isotopes in the gaseous products in the fluid, and / or one or more stable isotope analytical calibration factors.

[0024] In some examples, a computing device or processor can be configured or programmed with instructions for controlling one or more pumps, such as for controlling an injection rate or a production rate. In some examples, a computing device or processor can be configured or programmed with instructions for controlling one or more pumps based on one or more of the isotopic distribution of stable and / or radioactive isotopes contained in the biogenic feedstock, the isotopic distribution of stable and / or radioactive isotopes contained in the gaseous product in the fluid, or the amount or fraction of the gaseous product in the fluid derived from the biogenic feedstock. In some examples, a computing device or processor can be configured or programmed with instructions for identifying the isotopic distribution by determining the isotopic distribution or by receiving the isotopic distribution, such as by user input or by wired or wireless data communication. Optionally, the one or more stable isotope analytical calibration factors include, are characteristic of, or are derived from one or more isotopic fractionation factors. Optionally, one or more stable isotope analytical calibration factors are determined using radioisotope analytical techniques.

[0025] In some examples, the formation may be a coal bed or other coal-bearing formation, or an oil field or other oil, gas, or petroleum-bearing formation. The techniques described herein may be useful for coal bed formations because such formations may have significant amounts of water present; therefore, injecting a biogenic feedstock into a coal bed formation may allow the biogenic feedstock to permeate any areas where water may be present, although there may be limited understanding of how water moves or mixes within the formation. Furthermore, present coal can bind and adsorb to a variety of materials, but this is not limited to materials produced by microbial action.

[0026] The use of the techniques described herein may be even more advantageous for use in oil field formations, since such formations often contain oil-saturated sand, shale, or sandstone in addition to brine or other aqueous mixtures in the formation. Many oil field formations may be structured as waterflooded formations, with injection and production wells separated by some distance, but the flow and mixing of fluids through the formation between injection and production can be very well characterized and controlled. Such techniques may enable improved production of methane from biogenic feedstocks in oil field formations compared to coalbed formations.

[0027]

[0027] While not wishing to be bound by any particular theory, beliefs or understandings of basic principles related to the present invention may be discussed herein. It is recognized that regardless of the ultimate correctness of any mechanistic explanation or hypothesis, embodiments of the present invention may nevertheless be operable and useful. [Brief explanation of the drawings]

[0028] [Figure 1] 1 provides a schematic diagram of a geological formation containing a consortium of symbiotic microorganisms. [Figure 2] An overview of exemplary methods for producing and analyzing fluids from a geological formation is provided. [Figure 3] We present experimental data showing the relationship between δ13C and methane for different carbon sources. [Figure 4] 1 provides example plots of data for use in determining stable isotope analysis calibration factors for use in determining the amount of gaseous products that are biogenic in origin based on stable isotope analysis measurements. DETAILED DESCRIPTION OF THE INVENTION

[0029]

[0032] Geologic formations, such as those containing fossil fuels, are becoming increasingly depleted, for example, by fossil fuel mining or extraction. These depleted formations may be ideal locations for producing and / or storing large amounts of renewable fuels, such as biomethane or biohydrogen, and / or for carbon sequestration (e.g., in the form of carbon dioxide, CO). Because the amount of oxygen in the formation may be limited, such formations may be useful as anaerobic digesters that can produce and / or store large amounts of methane (CH) and possibly CO and / or molecular hydrogen (H).

[0030]

[0033] In some examples, a consortium of symbiotic methanogenic microorganisms may reside in or be inoculated into the formation. These microorganisms can be fed a carbonaceous feedstock to produce biomethane. If the carbonaceous feedstock is a biogenic feedstock (e.g., biogenic or biologically derived), the biomethane may not contribute to the global carbon balance. For example, the biogenic feedstock may be derived from photosynthesis, such as when CO2 is reduced to produce the biogenic feedstock, effectively removing carbon from the atmosphere, at least temporarily. When the biogenic feedstock is manipulated to produce biomethane, CO2 can be produced from the combustion and / or oxidation of the biomethane, and the carbon can be effectively returned to the atmosphere in the form of CO2.

[0031]

[0034] Storage of gaseous fuels, such as natural gas, in underground reservoirs has been practiced in the past. However, biofuel storage in underground reservoirs does not appear to have been widely adopted. One concern is the possibility that stored biofuels may mix with fossil fuels in the underground reservoir, especially if the underground reservoir is a fossil fuel reservoir (e.g., a depleted natural gas or oil reservoir). Similarly, if an underground reservoir is used directly as an anaerobic digester, biomethane produced by the digestion process may mix with the fossil methane present. In such cases, it can be difficult to determine whether gaseous fuels produced from such underground reservoirs are biogenic (e.g., biofuel) or fossil fuel. As climate change becomes an increasing concern, it is increasingly desirable to prove that produced gaseous fuels are biogenic. Described herein is a technique that uses isotope analysis to positively identify the amount of biogenic produced gas from a geological formation.

[0032]

[0035] The following definitions are provided to clarify their specific use in the context of the present invention.

[0033]

[0036] "Biogenic feedstock" refers to organic material produced by living organisms, or products (e.g., waste products) produced by or derived from organic material produced by living organisms. The term "biogenic feedstock" is intended to distinguish it from fossil fuels and feedstocks derived from fossil fuels.

[0034]

[0037] "Biogenic methane" or "biomethane" refers to methane (CH4) produced from biologically derived raw materials (e.g., biogenic feedstocks). Biomethane is contrasted with "fossil methane" or "paleomethane," which refers to fossil fuel methane or methane whose carbon is of geological age and typically originates from hydrocarbon-bearing formations or is produced from other hydrocarbons extracted from hydrocarbon-bearing formations. Biomethane and renewable methane are further distinguished from methane whose carbon originates from fossil carbon (e.g., fossil fuels) but is produced using energy from renewable sources (e.g., solar energy).

[0035]

[0038] "Geological formation" refers to a body of rock below the Earth's surface, which may differ from other adjacent bodies (e.g., based on rock type). A geological formation also includes an area within a body of rock that contains or hosts carbonaceous materials, such as coal, oil, or natural gas, or that previously contained or hosted such carbonaceous materials prior to extraction. Geological formations include those that have sufficient porosity and permeability to store and transmit fluids, such as liquids or gases, and are sometimes referred to herein as "underground reservoirs." In some instances, hydrocarbons (e.g., fossil fuels) can be extracted from some geological formations, and such formations can be depleted or include depleted areas, which can provide a reservoir for injecting other materials into the formation, such as for storing other materials (e.g., for long-term or short-term storage).

[0036]

[0039] A "consortium of symbiotic microorganisms" refers to a mixture of different microorganisms that inhabit a particular environment (e.g., a geological formation). In some instances, the consortium of symbiotic microorganisms includes methanogens that produce methane from carbonaceous feedstocks under anaerobic conditions.

[0037]

[0040] "Radioisotope analysis" refers to the process of assessing the relative abundance of radioisotopes in one or more chemical species. Radioisotope analysis is useful for tracking specific atoms in chemical reactions or the amounts of chemical species of different origin in a mixture.

[0038]

[0041] "Stable isotope analysis" refers to the process of assessing the relative abundance of different stable isotopes of an element. Stable isotope analysis is performed on a single chemical species (e.g., CH4) to determine the amount of different stable isotopes present in the single chemical species (e.g., for CH4, 13 C and 12 In some instances, stable isotope analysis can be performed on the reactants and products of a chemical reaction to identify one or more isotopic fractionation factors.

[0039]

[0042] "Isotopic fractionation factor" refers to a measure of the degree to which different isotopes of an element are favored by a chemical reaction or process.

[0040]

[0043] As mentioned above, isotopic analysis can be used to positively identify the amount of produced gas from biogenic formations. Two different types of isotopic analysis are described herein that can be used individually or together to assess the origin of produced fuel. In the first example, radioisotope analysis can be used. In the second example, stable isotope analysis can be used. In some cases, both radioisotope analysis and stable isotope analysis are used together, such as for calibration or validation purposes.

[0041]

[0044] In some instances, radioisotope analysis is useful for distinguishing between biogenic carbon and carbon of ancient origin (e.g., fossil carbon). Radioisotope analysis involves the detection of radioactive isotopes of elements in a sample (e.g., 14 For example, determining the relative abundance of a radioisotope with a half-life of approximately 5700 years. 14 C is produced in the Earth's atmosphere by the interaction of nitrogen atoms with cosmic rays, so there is generally always some amount of C in the Earth's biosphere, organisms, and biomass due to the uptake of CO2 from the atmosphere by plants. 14 In contrast, carbon that has been fixed underground for a long time (e.g., fossil carbon) has an age of 10 ... 14 Half-life of C or14 Because it exceeds the half-life of C by several times, 14 Carbon tends to be depleted (e.g., completely depleted even in the youngest fossil carbon deposits). Thus, when a biogenic gas (e.g., biomethane) is mixed with the same gas of ancient origin (e.g., fossil methane), radioisotope analysis can be used to determine the relative amounts of gas in the mixture that each contributes.

[0042]

[0045] for example, 14 Any C-containing gas can be of biogenic origin. 14 By knowing the abundance of C, 14 C is expected to be present in biogenic gases. As an example, atmospheric CO2 is estimated to be approximately 1 part per trillion 14 A biofuel derived from such a biogenic feedstock (e.g., biomethane), when pure, can have an abundance of C, and modern biogenic feedstocks have essentially the same abundance. 14 It has C.

[0043]

[0046] In the case of methane produced from geological formations where a consortium of symbiotic microorganisms exists to digest the biogenic feedstock injected into the formation, the amount of methane in the produced methane is 14 If the abundance of C is about 1 part per trillion, for example, it can be determined that about 100% of the methane produced is biogenic. 14 If the abundance of C is about 0.1 parts per trillion, then about 10% of the methane produced can be determined to be of biogenic origin, and about 90% of the methane produced can be determined to be of fossil origin. 13 C and 12 Compared to C 14 It will be appreciated that a fraction factor, which represents the relative rate at which C undergoes chemical reactions, can be used to provide a more accurate measure of the amount of biogenic produced gas.

[0044]

[0047] 14 Radioisotope analysis of C can be used to determine the amount or fraction of biogenic manufactured gas, but radioisotope analysis is complex, time-consuming, and expensive. Other analytical techniques, such as stable isotope analysis, can be less complex, less time-consuming, and less expensive, but these techniques are 14 It may not be as accurate as radioisotope analysis of C.

[0045]

[0048] Stable isotope analysis involves determining the stable isotopes of elements in a sample (e.g., 12 C and 13 C) determining the relative abundance of natural 12 C and 13 The relative abundance of C was approximately 98.89% 12 C and 1.11% 13 C, but in the sample 12 C and 13 The relative abundance of C can vary, for example: 12 C-containing species and similar 13 When a reaction occurs involving a C-containing species, 12 C-containing species and similar 13 The reaction rates of C-containing species may differ. In some cases, the reaction rate may only change slightly, but the relative reaction rates between reactants and products may vary. 12 C and 13 Measurable changes in C abundance can occur. The relative changes between the starting material (e.g., biogenic feedstock) and the final product (e.g., biomethane) 12 C and 13 Differences in C abundance can be influenced by various factors, such as the number of reaction steps, the anaerobic digestion pathway used, and the isotopic content of the biogenic feedstock. Additionally, the relative abundance of fluids in the formation (e.g., fossil methane) that may be mixed with the end product (e.g., biomethane) can also be affected. 12 C and 13 The C abundance is the relative abundance of the produced fluid from the formation. 12 C and 13 Although carbon isotopes are listed, other stable isotopes (e.g., 16 O and 18 The relative abundance of β- and β-O can be analyzed similarly.

[0046]

[0049] Once the relative abundances of stable isotopes in the biogenic feedstock, the produced gas, and optionally any fossil-source gases in the formation (e.g., determined prior to injecting the biogenic feedstock) are determined, this information can be combined with information obtained from radioisotope analysis as validation of the abundance analysis of the produced gas. For example, the stable isotope abundances in the produced gas can be affected by contributions from biogenic and fossil-source gases, and the relative amounts of biogenic and fossil-source gases obtained by radioisotope analysis can provide calibration factors for the stable isotope analysis. In some instances, these calibration factors can be used in subsequent analyses in which stable isotope analysis is used to determine the relative amounts of biogenic and fossil-source gases without the need to repeat the radioisotope analysis.

[0047]

[0050] It will be understood that the techniques described herein do not rely on isotopic tracers or isotopic labels, such as those described in U.S. Patent Application Publication No. 2012 / 0036923, which is incorporated herein by reference, where an artificially enhanced isotopic distribution of a particular chemical species is introduced into a system. For example, isotopic tracers have sometimes been used to track the conversion of fossil carbon to fossil methane in geological formations. Instead, the techniques described herein utilize the natural isotopic distribution of biogenic carbon to distinguish it from fossil carbon, which has a distinct isotopic distribution. The techniques described herein intentionally utilize biogenic feedstocks with naturally occurring carbon isotopic abundances that differ from fossil carbon to produce biomethane. This biomethane exhibits the isotopic signature characteristics of the biogenic feedstock, which differ from the isotopic characteristics of fossil-derived methane.

[0048]

[0051] It will be further understood that the techniques described herein are not limited to isotopically distinguishing biogenically produced gaseous products from background gas present in a coal reservoir and tracking biogas migration within the coal reservoir for mapping purposes, as described in U.S. Patent Application Publication No. 2012 / 0036923. Instead, the techniques described herein utilize biogenic feedstocks for the generation of biogenic gas within the formation and subsequent production of gas, and are useful for identifying the amount of produced gas that is biogenic in origin based on the radioisotope and / or stable isotopic signatures of the biogenic feedstock and the produced gas, without requiring specific isotopic analysis of gases or fluids present in the formation prior to the introduction of the feedstock and the production of biogenic gas. For example, certain embodiments of the disclosed techniques do not use or require isotopic analysis of background gas present in the formation. The disclosed techniques can use both stable and radioisotope analysis, with radioisotope analysis optionally being used to calibrate or standardize the stable isotope analysis, such as to estimate or determine measurements of isotopic fractionation. The combination of stable and radioisotope analysis described provides a simplified, efficient, and reliable method for determining whether and how much gas produced from a geological formation is biogenic, offering advantages over stable or radioisotope analysis alone.

[0049]

[0052] 1 provides a schematic diagram of an exemplary system 100 showing a geological formation 101 containing a consortium of symbiotic microorganisms. One or more wells 105 are shown in the formation 101. The one or more wells 105 are shown in fluid communication with one or more pumps 110 for injecting biogenic feedstock from a storage vessel 115 into the formation 101. The one or more wells 105 are also shown in fluid communication with one or more pumps 120 for producing fluids from the formation 101. The produced fluids may be directed, at least temporarily, to a storage tank 125 for further processing, storage, distribution, analysis, etc.

[0050]

[0053] In some examples, sampling ports (not shown) may be included in the storage vessel 115 or storage tank 125, or elsewhere in the system, to allow for obtaining samples of the biogenic feedstock and / or produced fluids so that the material can be subjected to radioisotope analysis and / or stable isotope analysis. In some examples, radioisotope analysis and / or stable isotope analysis may be performed on manually obtained samples of the produced fluids from the formation 101 to determine the isotope distribution of these samples, although automated sampling may also be used, such as when samples of the produced fluids are obtained periodically using a robotic, automated, or remotely controlled sampling system. Similarly, in some examples, isotope analysis may be performed on manually obtained samples of the biogenic feedstock to determine the isotope distribution of the biogenic feedstock, although automated sampling may also be used, such as when samples of the biogenic feedstock are obtained periodically using a robotic, automated, or remotely controlled sampling system. The isotope analysis may be performed at the location where the produced fluid samples are obtained, or may be performed remotely, such as in a remote laboratory or other analytical facility. Isotope analysis can use any suitable analytical technique or system, including, but not limited to, cavity ring-down spectroscopy, accelerator mass spectrometry, etc. In some examples, stable isotope analysis and radioisotope analysis can be performed on a single sample, although different samples can be used for stable isotope analysis and radioisotope analysis.

[0051]

[0054] System 100 is further shown including a computing device 150, which may include one or more processors and a non-transitory computer-readable storage medium including instructions that, when executed by the one or more processors, cause the one or more processors to perform operations. In some examples, the instructions and / or operations may include operations for configuring the computing device to identify an isotopic distribution of stable isotopes and / or radioactive isotopes included in a biogenic feedstock, identify an isotopic distribution of stable isotopes and / or radioactive isotopes included in a gaseous product in a fluid, and determine the amount of gaseous product in a fluid derived from the biogenic feedstock. In some examples, operations corresponding to identifying an isotopic distribution of stable isotopes and / or radioactive isotopes in a fluid and / or in a gaseous product in a biogenic feedstock may be performed by a system that receives the isotopic distribution, such as via one or more inputs or via one or more data or network communications. In some examples, computing device 150 may be in data and / or control communication with one or more isotope analysis systems to control or receive isotopic distribution information from such systems.

[0052]

[0055] Computing device 150 may optionally be in data or control communication with one or more pumps 110 and / or one or more pumps 120, such as to control and / or monitor the injection of biogenic feedstock or the production of fluids. As an example, results from one or more isotopic analyses may be used to determine operational decisions regarding the injection of material into or the production of material from formation 101. Operational decisions may include, for example, changing the injection rate, changing the production rate, changing the composition of the biogenic feedstock, etc. For example, biogenic feedstock may be provided as a component of an aqueous fluid injected into the formation, and the blending rate of the biogenic feedstock or other additives in the aqueous fluid (e.g., growth nutrients, trace elements, etc.) may be controlled. Computing device 150 may optionally be in data or control communication with one or more other sensor or control devices (not shown in FIG. 1 ) that may be used to monitor and / or control the production rate, injection rate, blending amount, etc., according to one or more inputs or automated decisions based on the isotopic analyses, etc.

[0053]

[0056] 2 provides an overview of an exemplary method 200 for producing and analyzing fluids from a geological formation according to various techniques described herein. Method 200 begins at block 205, where a biogenic feedstock is injected into the formation. The formation may contain a consortium of symbiotic microorganisms capable of anaerobically digesting the biogenic feedstock, such as to produce gaseous products (e.g., CH4). In some examples, the formation may include a coalbed formation or an oil field formation. The biogenic feedstock may be analyzed for its known radioisotope content (e.g., 14 C) and / or known distribution of stable isotopes (e.g., 12 C and 13 Because anaerobic digestion can take some time depending on formation conditions, method 200 can include allowing a suitable amount of time to pass (e.g., 1 hour to 10 years).

[0054]

[0057] At block 210, fluids are produced from the formation. The produced fluids can include gaseous products (e.g., CH), at least a portion of which corresponds to gaseous products (e.g., bio-CH) produced by digesting a biogenic feedstock by a consortium of symbiotic microorganisms. In some examples, the produced fluids can include a portion of the gaseous products that are not produced by a consortium of symbiotic microorganisms and / or may be of fossil origin (e.g., fossil CH). The produced fluids can optionally include other components, such as non-reactive or inert gases (e.g., N or Ar), or other gaseous components present in the formation (e.g., CO), or other gaseous components (e.g., H) produced by a consortium of symbiotic microorganisms.

[0055]

[0058] At block 215, a radioisotope analysis of at least a portion (e.g., gaseous portion) of the produced fluid is performed, such as to determine the relative amount of gaseous products in the produced fluid derived from the biogenic feedstock. The radioisotope analysis can include identifying the abundance of the same radioisotopes that were contained in the biogenic feedstock that are present in the gaseous products in the produced fluid. This abundance can be used to determine the relative amount of gaseous products in the produced fluid derived from the biogenic feedstock.

[0056]

[0059] The relative amounts of gaseous products in the produced fluid derived from the biogenic feedstock are used to determine one or more stable isotope analysis calibration factors at block 220. The stable isotope analysis calibration factors are generated in parallel with the stable isotope analysis of the produced fluid and the biogenic feedstock to determine the extent of stable isotopes in the biogenic feedstock section in the relative amounts of gaseous products in the produced fluid derived from the biogenic feedstock.

[0057]

[0060] It will be understood that blocks 215 and 220 of method 200 need not be performed for all embodiments of method 200. In some examples, method 200 may branch from block 210 to block 225, where stable isotope analysis of the produced fluid is performed to determine the relative amount of gaseous products in the produced fluid derived from the biogenic feedstock, such as using the stable isotope analysis calibration factor determined in block 220.

[0058]

[0061] In this way, the complex, time-consuming and expensive process of radioisotope analysis can be performed only a limited number of times, such as to determine one or more calibration factors and / or as periodic verification / recalibration, while the less complex, less time-consuming and less expensive process of stable isotope analysis can be used more regularly or routinely, such as to verify and / or track the relative amounts of gaseous products in produced fluids derived from biogenic feedstocks.

[0059]

[0062] In some cases, the relative amount of gaseous products in the produced fluids derived from the biogenic feedstock can be used in a feedback mechanism to control the rate at which the biogenic feedstock or other additives or components mixed with the biogenic feedstock are injected into the formation and / or the rate at which fluids are produced from the formation.

[0060]

[0063] The present invention can be further understood by the following non-limiting examples. [Example]

[0061]

[0064] Example 1 Carbon is divided into three different carbon isotopes ( 14 C / 13 C / 12The resulting sample is analyzed by an accelerator mass spectrometer (AMS) to determine the ratio of carbon-14 to carbon-13. At the end of the AMS run, the collected data is the number of carbon-14 atoms in the sample, as well as the amount of carbon-12 and carbon-13. From these data, the concentration ratio of the isotopes can be known, allowing for an assessment of the fractionation level, which is essentially a given bias in the data due to mass effects. Once fractionation is corrected, the sample's 14 Calibrate C against the NBS (National Bureau of Standards) oxalate standard. The internationally accepted radiocarbon dating standard is a d of -13‰ against Pee Dee Belemnite (PDB), a common normalization standard for stable gas isotope analysis, in 1950 AD. 13 The radiocarbon fraction or age of the oxalate standard is determined as follows: A ON =0.95A OX [1-2(d 13 C+19) / 1000] A ON : 14 of oxalate normalized to the C fraction 14 C activity. A OX :Oxalic acid 14 C activity. 19‰d 13 C correction is the 14 Taking into account the fraction of C.

[0062]

[0065] Radiocarbon dating of produced samples: For produced water or gas studies, use pmc (percent modern carbon) notation. pmc=(A SN / A abs )100%=A SN [A ON e l(y-1950) ] -1 100% A SN :d 13 Activity of samples normalized to fractions using C . AON :Oxalic acid 13 C normalized activity. A abs : Absolute value of the sample 14 C activity. · y: Year of measurement of oxalic acid.

[0063]

[0066] The resulting percent modern carbon calculation quantifies the percentage of modern carbon-containing molecules that are meant to originate from the injected carbon substrate.

[0064]

[0067] A complicating factor in the analysis is the potential use of fossil carbon dioxide by methanogens via hydrogenation pathways. Table 1 shows how carbon dioxide is produced and consumed by methanogenic fermentation of the model waste biomass compound glycerol. [Table 1]

[0065]

[0068] Methanogenic fermentation of 1 mole of glycerol produces 1.75 moles of methane, but the CO2 consumed during hydrogenotrophic methanogenesis likely comes from a large pool of aqueous CO2 produced over geological time and therefore does not contain carbon-14. This means that under these feedstock conditions, the apparent age of methane produced solely from renewable carbon will be 57% modern (1 / 1.75).

[0066]

[0069] Example 2 Both stable and radioisotope analysis have advantages and disadvantages. Stable isotope analysis is fast and inexpensive, but requires repeated calibration using laboratory systems to accurately assess the volume of new methane production. Radioisotope analysis can provide a direct measure of renewable elements in a feedstock, but is hindered by its slow and expensive nature. To take advantage of the unique values ​​of each analysis, a calibration between the two can be performed, where both radioisotope and stable isotope analyses are performed on the same sample to obtain a constant or relationship that allows radiocarbon results to be predicted from stable isotope results.

[0067]

[0070] Example 3 An alternative method for determining the conversion of renewable biomass to renewable carbon is the use of stable isotopes. Chemical bonds formed with heavier stable isotopes are stronger (e.g., 13 C vs. 12 C. 2 H vs. 1 H), thus microbial conversion of feedstocks containing lighter elements to methane occurs preferentially. Because fossil carbon is locked in place and has been locked in place for geological time, historical biological conversion of these feedstocks will be biased toward consumption of lighter isotopes, leaving heavier stable isotopes in place. As an example, when newly introduced renewable carbon is introduced into a system, it still contains the natural carbon-13 isotope composition (1.1%), whereas fossil carbon contains a greater proportion of carbon-13 due to historical microbial consumption of carbon-12.

[0068]

[0071] Laboratory data (obtained using cavity ring-down spectroscopy) shown in Figure 3 demonstrate that when methane is produced in field-derived produced fluid samples supplied with different feedstocks, there is a strong linear relationship between the volume of methane produced and the stable carbon isotope composition of the resulting methane gas. The control sample (red) exhibits a high carbon isotope ratio of fossil carbon delta 13Samples that identify the C signature, shown in blue, correspond to methane produced using a renewable feedstock and produced fluid consortium. This linear relationship can be used to quantify the mass of new methane produced based on gas isotopic composition. This relationship generally depends on environmental characteristics and can therefore be empirically determined in a laboratory setting for each reservoir targeted for feedstock injection.

[0069]

[0072] Example 4 This example describes isotope analysis measurements to determine stable isotope analysis calibration factors and their subsequent use to determine the amount of gaseous products produced by anaerobic digestion that are biogenic in origin. When expressed as a fractional or relative amount, the amount of gaseous products produced by anaerobic digestion that are biogenic in origin is also referred to as percent modern carbon (pmc).

[0070]

[0073] A sample of methane gas produced by anaerobic digestion is obtained. In some cases, the sample is mixed with a quantity of fossil methane as a diluent. The sample is subjected to stable isotope analysis to determine the delta value (δ 13 C) is determined. For example, 13 C vs. 12 Determine the ratio of C and C in the standard 13 C vs. 12 C ratio for PDB limestone as a standard. 13 C vs. 12 The delta value of the sample is obtained using the following formula:

number

[0071]

[0074] Radioisotope analysis of the samples is also performed to determine an absolute measure of percent modern carbon (pmc) for each sample, as described above with respect to Example 1. The pmc measurements and δ 13Using the C measurements, the values ​​can be referenced to each other to determine stable isotope analysis calibration factors. Figure 4 shows the PMC determined by radioisotope analysis versus the δ determined by stable isotope analysis. 13 1 provides plots showing exemplary results of C.

[0072]

[0075] In this example, a clear relationship is observed, and a regression or other analysis of the data can be performed to determine the stable isotope analysis calibration coefficient, in this case the regression constant output by the regression analysis, and the type of regression used.

[0073]

[0076] Once the stable isotope analysis calibration factor is determined, the above process can be performed to determine stable isotope measurements of additional samples, which can then be used in conjunction with the stable isotope analysis calibration factor to quickly determine the mass (pmc) of a sample of gaseous products produced by anaerobic digestion that are biogenic in origin, possibly with uncertainty accounted for by regression analysis. Table 2 shows the additional δ 13 Illustrated are exemplary C measurements and corresponding pmc values ​​output using stable isotope analysis calibration factors. Determining pmc values ​​using stable isotope analysis results in this manner offers significant advantages, as stable isotope analysis measurements are significantly less complex and time consuming than radioisotope analysis, thereby enabling real-time or near real-time determination of the amount of biogenic carbon in gas produced from the formation. [Table 2]

[0074]

[0077] References U.S. Patent Application Publication No. 2012 / 0036923, Valentine, "Tracer Method to Estimate Rates of Methane Generation Through Augmentation or Biostimulation of the Sub-Surface," February 16, 2012.

[0075]

[0078] Palstra et al., 2014, “Biogenic Carbon Fraction of Biogas and Natural Gas Fuel Mixtures Determined with 14 C,” Radiocarbon,Vol 56,No 1,pp.7-28,DOI:10.2458 / 56.16514

[0076]

[0079] Taguchi et al.,”Biobased carbon content of resin extracted from polyethylene composite by carbon-14 concentration measurements using accelerator mass spectrometry” SpringerPlus,3:6,DOI:10.1186 / 2193-1801-3-6

[0077]

[0080] Incorporation by Reference and Modification Statement All references throughout this application, e.g., patent documents, including issued or granted patents or equivalents and published patent applications, as well as non-patent documents or other source materials, are incorporated by reference in their entirety herein, as though individually incorporated by reference.

[0078]

[0081] All patents and publications mentioned in this specification are indicative of the level of skill of those skilled in the art to which this invention pertains. The references cited herein are hereby incorporated by reference in their entirety to indicate the state of the art as of the filing date, if any, and it is intended that this information may be used herein to exclude (e.g., disclaim) certain embodiments of the prior art, if appropriate.

[0079]

[0082] When groups of substituents are disclosed herein, it is understood that all individual members of the group and all subgroups and classes that can be formed using the substituents are separately disclosed. When Markush groups or other groupings are used herein, it is intended that all individual members of the group and all possible combinations and subcombinations of the group are individually included in the disclosure. As used herein, "and / or" means that one, all, or any combination of the items in the list separated by "and / or" is included in the list; for example, "1, 2, and / or 3" is equivalent to "1, 2, 3, 1 and 2, 1 and 3, 2 and 3, or 1, 2, and 3."

[0080]

[0083] Unless otherwise specified, the present invention can be practiced using any combination or formulation of the components described or exemplified. It is understood that those skilled in the art may name the same materials differently, and so specific names for materials are intended to be exemplary. It will be understood that methods, device elements, starting materials, and synthetic methods other than those specifically exemplified can be used in the practice of the present invention without resorting to undue experimentation. All art-known functional equivalents of any such methods, device elements, starting materials, and synthetic methods are intended to be encompassed by the present invention. Whenever a range, e.g., a temperature range, time range, or composition range, is given herein, all intermediate ranges and subranges, as well as all individual values ​​falling within the given range, are intended to be encompassed by the present disclosure.

[0081]

[0084] As used herein, "comprising" is synonymous with "including," "containing," or "characterized by," is inclusive or open-ended, and does not exclude additional, unrecited elements or method steps. As used herein, "consisting of" excludes elements, steps, or ingredients not specified in the claim element. As used herein, "consisting essentially of" does not exclude materials or steps that do not materially affect the basic and novel characteristics of the claim. Any recitation herein of the term "comprising," particularly in a description of components of a composition, a description of a method, or a description of elements of a device, is understood to encompass compositions, methods, or devices consisting essentially of, and consisting of, the recited components or elements, optionally in addition to other components or elements. The inventions illustratively described herein may suitably be practiced in the absence of any element or elements, or limitation or limitations not specifically disclosed herein.

[0082]

[0085] The terms and expressions which have been employed are used as terms of description rather than of limitation, and there is no intention in the use of such terms and expressions to exclude equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention as claimed. Thus, while the present invention has been specifically disclosed by examples, embodiments and optional features, it will be understood that modifications and variations of the concepts disclosed herein may be practiced by those skilled in the art, and that such modifications and variations are deemed to be within the scope of the invention as defined by the appended claims.

Claims

1. injecting a biogenic feedstock into a geological formation, the formation containing a consortium of symbiotic microorganisms, the consortium of symbiotic microorganisms at least partially anaerobically digesting the biogenic feedstock to produce gaseous products, the biogenic feedstock containing a known amount of a radioisotope; producing fluids from the formation, the fluids comprising the gaseous product; performing a radioisotope analysis of at least a portion of the fluid using the known amount of the radioisotope to identify an amount of the gaseous products in the fluid derived from the biogenic feedstock; A method comprising:

2. determining one or more stable isotope analytical calibration factors using the amount of the gaseous product in the fluid derived from the biogenic feedstock; The method of claim 1 further comprising:

3. injecting a second biogenic feedstock into a second formation, the second formation comprising a second consortium of symbiotic microorganisms, the second consortium of symbiotic microorganisms at least partially anaerobically digesting the second biogenic feedstock to produce the gaseous product; producing a second fluid from the second formation, the second fluid comprising the gaseous product; performing a stable isotope analysis of at least a portion of the second fluid using the one or more stable isotope analysis calibration factors to determine a second amount of the gaseous product in the second fluid derived from the second biogenic feedstock; The method of claim 2 further comprising:

4. 4. The method of claim 3, wherein the stable isotope analysis of at least a portion of the second fluid is performed without excluding, including, or measuring a baseline isotope distribution of gases that were present in the second formation prior to injecting the second biogenic feedstock.

5. 4. The method of claim 3, wherein the step of producing the second fluid is performed during or after injecting the second biogenic feedstock.

6. The method of claim 3 , wherein the formation and the second formation are the same formation.

7. 3. The method of claim 2, wherein the one or more stable isotope analytical calibration factors comprise, are characteristic of, or are derived from one or more isotope fractionation factors.

8. determining the one or more stable isotope analytical calibration factors using the amount of the gaseous products in the fluid derived from the biogenic feedstock, determining the isotopic distribution of stable isotopes contained in the biogenic feedstock; determining an isotopic distribution of the stable isotopes contained in the gaseous product in the fluid; said one or more stable isotope analytical calibration coefficients, the isotopic distribution of the stable isotopes contained in the biogenic feedstock; the isotopic distribution of the stable isotopes contained in the gaseous product in the fluid; and the amount of the gaseous product in the fluid derived from the biogenic feedstock; determining using The method of claim 2 , comprising:

9. The stable isotopes contained in the biogenic feedstock １２ C or １３ C, and the stable isotope contained in the gaseous product １２ C or １３ The method of claim 8 , comprising C.

10. The radioisotope １４ The method of claim 1 , comprising C.

11. The gaseous product is CH ４ , CO ２ , H ２ or any combination thereof.

12. 10. The method of claim 1, wherein the biogenic feedstock comprises waste glycerol, waste erythritol, waste sorbitol, or waste maltitol, wastewater, a waste product, a source of carbonaceous material, or any combination thereof.

13. 10. The method of claim 1, wherein the radioisotope analysis of at least a portion of the fluid is performed without excluding, including, or measuring a baseline isotopic distribution of gases that were present in the formation prior to injecting the biogenic feedstock.

14. The method of claim 1 , wherein the step of producing the fluid is performed during or after injecting the biogenic feedstock.

15. The method of claim 1 , wherein the formation is an oil field formation or a coal bed formation.

16. identifying one or more stable isotope analytical calibration coefficients; injecting a biogenic feedstock into a geological formation, the formation including a consortium of symbiotic microorganisms, the consortium of symbiotic microorganisms at least partially anaerobically digesting the biogenic feedstock to produce gaseous products; producing fluids from the formation, the fluids comprising the gaseous product; performing a stable isotope analysis of at least a portion of the fluid using the one or more stable isotope analysis calibration factors to determine the amount of the gaseous products in the fluid derived from the biogenic feedstock; A method comprising:

17. 17. The method of claim 16, wherein the one or more stable isotope analytical calibration factors comprise, are characteristic of, or are derived from one or more isotope fractionation factors.

18. identifying the one or more stable isotope analytical calibration coefficients injecting a second biogenic feedstock into a second geological formation, the second geological formation including a second consortium of symbiotic microorganisms, the second consortium of symbiotic microorganisms at least partially anaerobically digesting the second biogenic feedstock to produce the gaseous product, the second biogenic feedstock containing a known amount of a radioisotope; producing a second fluid from the second formation, the second fluid comprising the gaseous product; performing a radioisotope analysis of at least a portion of the second fluid using the known amount of the radioisotope to determine the one or more stable isotope analysis calibration factors; 17. The method of claim 16, comprising:

19. 20. The method of claim 18, wherein the radioisotope analysis of at least a portion of the second fluid is performed without excluding, including, or measuring a baseline isotopic distribution of gases that were present in the second formation prior to injecting the second biogenic feedstock.

20. 20. The method of claim 18, wherein producing the second fluid is performed during or after injecting the second biogenic feedstock.

21. The radioisotope １４ 20. The method of claim 18, comprising C.

22. 20. The method of claim 18, wherein the formation and the second formation are the same formation.

23. performing the stable isotope analysis of at least a portion of the fluid, determining the isotopic distribution of stable isotopes contained in the biogenic feedstock; determining an isotopic distribution of the stable isotopes contained in the gaseous product in the fluid; the amount of the gaseous product in the fluid derived from the biogenic feedstock, the isotopic distribution of the stable isotopes contained in the biogenic feedstock; an isotopic distribution of the stable isotopes contained in the gaseous product in the fluid; and said one or more stable isotope analytical calibration factors; determining using 17. The method of claim 16, comprising:

24. The stable isotopes contained in the biogenic feedstock １２ C or １３ C, and the stable isotope contained in the gaseous product １２ C or １３ 24. The method of claim 23, comprising C.

25. The gaseous product is CH ４ , CO ２ , H ２ or any combination thereof.

26. 17. The method of claim 16, wherein the biogenic feedstock comprises waste glycerol, waste erythritol, waste sorbitol, or waste maltitol, wastewater, a waste product, a source of carbonaceous material, or any combination thereof.

27. 17. The method of claim 16, wherein the stable isotope analysis of at least a portion of the fluid is performed without excluding, including, or measuring a baseline isotopic distribution of gases that were present in the formation prior to injecting the biogenic feedstock.

28. 17. The method of claim 16, wherein the step of producing the fluid is performed during or after injecting the biogenic feedstock.

29. 17. The method of claim 16, wherein the formation is an oil field formation or a coal bed formation.

30. one or more pumps in fluid communication with a geological formation containing a consortium of symbiotic microorganisms; injecting a biogenic feedstock into the formation, and causing the consortium of symbiotic microorganisms to at least partially anaerobically digest the biogenic feedstock to produce gaseous products; Producing a fluid from the formation, the fluid comprising the gaseous product. one or more pumps configured to 1. A computing device comprising: Identifying the isotopic distribution of stable isotopes contained in the biogenic feedstock; identifying an isotopic distribution of the stable isotopes contained in the gaseous product in the fluid; the amount of the gaseous product in the fluid derived from the biogenic feedstock, the isotopic distribution of the stable isotopes contained in the biogenic feedstock; the isotopic distribution of the stable isotopes contained in the gaseous product in the fluid; and One or more stable isotope analytical calibration factors Use to determine a computing device configured to A system comprising:

31. 31. The system of claim 30, wherein the one or more stable isotope analytical calibration coefficients comprise, are characteristic of, or are derived from one or more isotope fractionation factors, or the one or more stable isotope analytical calibration coefficients are determined using radioisotope analytical techniques.

32. The gaseous product is CH ４ , CO ２ , H ２ 31. The system of claim 30, wherein the biogenic feedstock comprises waste glycerol, waste erythritol, waste sorbitol, or waste maltitol, wastewater, a waste product, a source of carbonaceous material, or any combination thereof.

33. 31. The system of claim 30, wherein the formation is an oil field formation or a coal bed formation.

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