A method for improving CO2 capture and mineralization via alternating water-gas injection in underground rock reservoirs

Abstract

Methods for capturing and mineralizing CO2 in rock reservoirs, such as those containing high concentrations of mafic minerals, are provided. The methods include injecting a first amount of free-phase supercritical CO2 into the rock reservoir at a first rate for a first duration, injecting a second amount of water into the rock reservoir at a second rate for a second duration, and alternating between repeating at least one of the injection steps over multiple injection cycles. The first and second amounts, the first and second rates, the first and second durations, and the total number of multiple injection cycles are selected to improve capture and mineralization efficiency in the rock reservoir and reduce the amount of energy and water consumed. These systems and methods have demonstrated effectiveness in diverse geographic locations, expanding the geographic storage area available for sequestering carbon dioxide.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 431,521, filed December 9, 2022, and U.S. Provisional Patent Application No. 63 / 608,339, filed December 11, 2023, the entire disclosures of each of which are expressly incorporated herein by reference.

[0002] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT This invention was made with government support under Grant No. DE-FE0029219 awarded by the U.S. Department of Energy. The government has certain rights in this invention. [Background technology]

[0003] To achieve the global climate goals set out in the Paris Agreement, it is estimated that hundreds of gigatons of geological carbon storage are needed to decarbonize the global economy through point-source capture and storage and to generate the gigatons of carbon dioxide removal required annually by 2050 and beyond (e.g., via direct air capture and storage). Conventional geological carbon storage, a mature technology first introduced for enhanced oil recovery (EOR), involves injecting CO2 into sedimentary rock formations, where the carbon is trapped underground by geological structures and most of the injected CO2 persists in free phase for thousands of years. Alternatively, carbon can be stored in mafic rocks, specifically through in situ mineralization, where carbon is sequestered in aqueous phase via dissolution and subsequently exists in mineral form through chemical weathering of silicates and precipitation of carbonates. Unlike geological storage in conventional sedimentary basins, in situ mineralization offers the advantageous possibility that the primary capture mechanism is geochemical rather than structural, as the injected carbon is ultimately sequestered in a stable, solid form. Mineralization of carbon injected into mafic rocks such as basalt is a promising technology for permanent geological storage, with the potential to reduce project liability, shorten the monitoring period required to ensure there are no leaks, improve public acceptability of projects, and expand the geographic area where geological carbon storage is feasible.

[0004] In situ mineralization in basalt has been demonstrated at field scale in two pilot experiments: the CarbFix project in Iceland and the Wallula project in Washington State, USA. In the CarbFix1 experiment, CO2 was dissolved in water at a water-to-gas ratio of approximately 25:1 prior to injection, resulting in near-complete mineralization within two years. The Wallula pilot injected free-phase (supercritical) CO2 but relied in part on structural mechanisms (low-permeability lava flows) to capture the CO2 underground while geochemical reactions proceeded, resulting in approximately 60% mineralization over the same time frame. While these two pilots were successful, significant questions remain regarding the effectiveness and timeframe of mineralization upon scaled-up injection, as well as the availability and use of large amounts of water.

[0005] While Wallula-style injection (100% CO2, no water) avoids some water-use issues and maximizes injection capacity per well, free-phase injection alone presents scale limitations. Silicate dissolution and carbonate precipitation reactions in basalt reservoirs are geochemically inhibited during large-scale free-phase CO2 injection, and it could take tens of thousands of years for injected CO2 to mineralize at such a scale. While direct reactivity between free-phase CO2 and silicate minerals has been documented, the efficiency with which injected free-phase CO2 can mineralize depends in part on the availability of formation water to dissolve the CO2, so mineralization is partially limited by the amount of formation water. While the use of seawater could mitigate water demand issues for the water-dissolution approach, further research, focusing on free-phase injection for in-situ mineralization, is needed to determine the feasibility of large-scale (megaton- or gigaton-scale) projects required to achieve climate significance.

[0006] Therefore, what is needed is an improved method of in situ CO2 mineralization that addresses at least the problems discussed above. Summary of the Invention

[0007] Accordingly, some embodiments of the disclosed subject matter are directed to methods and injection strategies for the remediation of large-scale in-situ mineralization via alternating water-gas ("WAG") injection of free-phase CO2 and water. In some embodiments, the methods involve injecting free-phase CO2 into porous mafic rock formations, where the free-phase CO2 dissolves in existing groundwater saturating the rock, followed by "flushing" the reservoir with water to rapidly replenish subsurface fluids. The WAG injection embodiments disclosed herein for mineralization avoid the limitations of conventional approaches discussed above. Incorporating free-phase CO2 into carbon injection into mafic reservoirs reduces water demand and increases injection capacity per well. Additionally, circulating water promotes geochemical reactions that result in solubility and mineral entrapment, shortening the time to mineralization during large-scale injection compared to free-phase-only scenarios.

[0008] According to one embodiment of the disclosed subject matter, there is provided a method for capturing and mineralizing CO2 in a rock reservoir, the method including injecting a first amount of free-phase CO2 into the rock reservoir at a first rate for a first duration, injecting a second amount of water into the rock reservoir at a second rate for a second duration, and alternating between repeating at least one of the injection steps over a plurality of injection cycles.

[0009] In some embodiments, the CO2 is trapped within the aqueous phase and / or mineralized within the rock reservoir.

[0010] In some embodiments, the rock reservoir is basaltic, silicate, mafic, ultramafic, sedimentary, or a combination thereof.

[0011] In some embodiments, the free phase CO2 is in supercritical form.

[0012] In some embodiments, the water is freshwater. In some embodiments, the water is seawater or saltwater. In some embodiments, the water is saturated with dissolved CO2. In some embodiments, the water is sourced from a rock reservoir.

[0013] In some embodiments, the total number of multiple injection cycles is in the range of about 2 to about 400.

[0014] In some embodiments, the first duration is in the range of about 1 day to about 416 days and the second duration is in the range of about 1 day to about 1,900 days.

[0015] In some embodiments, the first rate, in tons per day, is in the range of about 0.001% to about 80% of a first total amount of free-phase CO2 injected over multiple injection cycles, and the second rate, in tons per day, is in the range of about 0.01% to about 80% of a second total amount of water injected over multiple injection cycles. In some embodiments, the first rate is in the range of about 10 tons per day to about 20,548 tons per day. In some embodiments, the first rate is in the range of about 1,015 tons per day to about 20,548 tons per day, and the second rate is in the range of about 4,284 tons per day to about 25,000 tons per day.

[0016] In some embodiments, the ratio of the second amount to the first amount is in the range of about 0.5 to about 242. In some embodiments, the ratio of the second amount to the first amount is less than 30.

[0017] In some embodiments, the ratio of the second speed to the first speed is in the range of about 0.60 to about 16.7.

[0018] In some embodiments, the ratio of the second duration to the first duration is in the range of about 0.3 to about 15.2.

[0019] According to another embodiment of the disclosed subject matter, a method for designing a strategy for alternately injecting CO2 and water to capture and mineralize CO2 in a rock reservoir is provided. The method includes developing a model of the rock reservoir based on geological and geophysical data at or near the rock reservoir, selecting an amount of CO2 to be injected, selecting an amount of water to be injected, selecting characteristics associated with an injection site of the rock reservoir, modeling the effects of a plurality of injection parameters on capture efficiency and mineralization efficiency in the rock reservoir based at least in part on the characteristics of the selected injection site, and defining an injection strategy by defining a plurality of injection parameters to improve capture and mineralization efficiency, reduce energy consumption, and reduce water consumption. The plurality of injection parameters include a plurality of injection cycles, a ratio of an amount of water injected to an amount of CO2 injected, a ratio of a water injection rate to a CO2 injection rate, and a ratio of a water injection cycle duration to a CO2 injection cycle duration. Each injection cycle includes a first injection of CO2 and a second injection of water.

[0020] In some embodiments, the injection site characteristics include injection depth, injection site porosity, injection site permeability, temperature, pressure, rock reservoir composition, rock reservoir geological age, and water depth.

[0021] According to another embodiment of the disclosed subject matter, a method for capturing and mineralizing CO2 in a rock reservoir is provided. The method includes injecting a first amount of supercritical CO2 into the rock reservoir at a first rate for a first duration, injecting a second amount of water into the rock reservoir at a second rate for a second duration, and alternating at least one of the injection steps over a plurality of injection cycles. The water may be freshwater, seawater, brackish water, water sourced from the rock reservoir, or a combination thereof. The total number of the plurality of injection cycles is in the range of about 1 to about 400. The ratio of the second amount to the first amount is in the range of about 0.1 to about 35. The ratio of the second rate to the first rate is in the range of about 0.1 to about 17. The ratio of the second duration to the first duration is in the range of about 0.1 to about 16.

[0022] Further objects, aspects, features, and embodiments of the present technology will become apparent from the drawings and the following description.

[0023] Some embodiments of the present technology are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like reference numerals may indicate similar elements. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a flowchart of a method of mineralizing CO2 in a rock reservoir according to some embodiments of the disclosed subject matter. [Figure 2] 1 is a flowchart of a method for designing a strategy for alternating CO2 and water injection to mineralize CO2 in a rock reservoir, according to some embodiments of the disclosed subject matter. [Figure 3] 1 is a graph showing the mass of mineralized CO2 versus time for selected simulations for a 1 Mt CO2 injection into the first example site, the Cascadia Basin. [Figure 4]FIG. 1 is a graph showing the mass of mineralized CO over time for three injection strategies simulating the injection of 1 Mt of CO into a first example site, Cascadia (solid line), and a second example site, Louisville (dashed line). [Figure 5] 10 is a graph showing improvement factors for a subset of simulated WAG scenarios at three example locations relative to WWAG. [Figure 6] 1 is a table outlining injection parameters and results for a simulated 1 Mt injection at the Cascadia site monitored for 40 years. [Figure 7] 10 is a table showing the results of a high-level sensitivity analysis for simulations performed using data from the Cascadia site. [Figure 8] 1 is a table showing the results of the scenarios investigated at three example locations. DETAILED DESCRIPTION OF THE INVENTION

[0025] Mineral carbon sequestration is an effective means of durable and verifiable geological carbon storage. Accordingly, some embodiments of the disclosed subject matter are directed to methods for improving subsurface mineralization via alternating water-gas ("WAG") injection of free-phase CO2 (e.g., supercritical) and water. Incorporating supercritical CO2 (scCO2) injection into basalt minimizes water demand, increases injection capacity per well, and expands the feasible scope of basalt carbon sequestration. Cycling water between scCO2 injections accelerates geochemical reactions that induce solubility and mineral entrapment. In some embodiments, injection strategies and models for aqueous-based injection, scCO2-only injection, and WAG injection into subsea and onshore basalt reservoirs were simulated. In some embodiments, WAG injection into mid-ocean ridge basalts of the Juan de Fuca Plate in the northeast Pacific Ocean was simulated to investigate injection parameters and reservoir characteristics that promote mineralization during WAG injection. In some embodiments, WAG injection improves mineralization yields to approximately 100% of 1 million metric tonnes ("Mt") of CO2 injection within 40 years. This improved WAG injection approach achieves approximately double the mineralization yield compared to conventional scCO2-only injection, while using half the water required for a water-dissolved approach. In some embodiments, WAG injection improves dissolution capture. In some embodiments, the efficiency of WAG injection was compared by simulating scenarios at two additional sites: offshore basalts at Louisville Seamount, a submarine volcano in the Southwest Pacific, and continental flood basalts along the Columbia River in Washington State. In some embodiments, faster mineralization occurred at Louisville Seamount than at the Juan de Fuca site, likely due to variability resulting from differences in the mineral composition of the injection zone. In some embodiments, the WAG scenario at the Columbia River site resulted in the greatest improvement in mineralization relative to scCO2-only injection and an increase in the achievable injection rate per well relative to a water-dissolved approach. Thus, embodiments of the disclosed subject matter improve carbon mineralization in basalt and substantially advance the scalability of WAG injection technology.

[0026] As shown in FIG. 1 , a method for capturing and mineralizing CO2 in a rock reservoir is generally designated by the numeral 100. At 110, method 100 includes selecting an injection reservoir. In some embodiments, the injection reservoir is a rock reservoir such as a mafic or ultramafic silicate rock. In some embodiments, the mafic silicate rock reservoir is basaltic, i.e., contains basalt at a concentration that allows contact with the injected fluid in the reservoir. At 120, method 100 includes injecting a first amount of CO2 into the rock reservoir at a first rate for a first duration. In some embodiments, the CO2 is free-phase CO2. In some embodiments, the free-phase CO2 is in supercritical form. Supercritical CO2 can be obtained by any suitable process, such as, for example, being produced at a remote location and transported to the injection reservoir, being produced near the injection reservoir, or a combination thereof. In some embodiments, the CO2 is pure supercritical CO2. At 130, the method includes injecting a second amount of water into the rock reservoir at a second rate for a second duration. In some embodiments, the water is fresh water. In some embodiments, the water is seawater or salt water. In some embodiments, the water is saturated with dissolved CO2. In some embodiments, the water is sourced from, e.g., extracted from, the rock reservoir to help manage reservoir pressure and / or to reduce water requirements during injection.

[0027] At 140, the method includes alternating at least one of the injection steps over a plurality of injection cycles. In some embodiments, each injection cycle includes a CO2 injection subcycle of a first amount of CO2, e.g., consistent with step 120 described above, and a water injection subcycle of a second amount of water, e.g., consistent with step 130 described above. In some embodiments, the CO2 injection subcycle occurs before the water injection subcycle. In some embodiments, the water injection subcycle occurs before the CO2 injection subcycle. Thus, the disclosed subject matter is not limited to any particular order of injection subcycles, so long as the CO2 injection subcycles and water injection subcycles alternate. In some embodiments, each injection cycle includes either a CO2 injection of a first amount of CO2, e.g., consistent with step 120 described above, or a water injection of a second amount of water, e.g., consistent with step 130 described above. In some embodiments, injection parameters such as the first amount, the second amount, the first rate, the second rate, the first duration, the second duration, and the total number of injection cycles are selected to improve mineralization efficiency in the rock reservoir. In some embodiments, the injection parameters are selected to improve CO2 capture by dissolution within the rock reservoir. In some embodiments, the injection parameters are selected to reduce the amount of energy consumed throughout the injection process. In some embodiments, the injection parameters are selected to reduce the amount of water consumed within the rock reservoir. In some embodiments, the injected CO2 is captured within the aqueous phase and / or mineralized within the rock reservoir.

[0028] In some embodiments, the total number of the plurality of infusion cycles is in the range of about 2 to about 400. In some embodiments, the total number of the plurality of infusion cycles is in the range of about 2 to about 45. In some embodiments, the total number of the plurality of infusion cycles is about 2. In some embodiments, the total number of the plurality of infusion cycles is about 3. In some embodiments, the total number of the plurality of infusion cycles is greater than about 45. In some embodiments, the total number of the plurality of infusion cycles is in the range of about 20 to about 45. In some embodiments, the total number of the plurality of infusion cycles is in the range of about 23 to about 45. In some embodiments, the total number of the plurality of infusion cycles is in the range of about 37 to about 45. In some embodiments, the total number of the plurality of infusion cycles is about 23.

[0029] In some embodiments, the first duration is in the range of about 1 day to about 416 days, and the second duration is in the range of about 1 day to about 1,900 days. In some embodiments, the first duration is in the range of about 5 days to about 416 days, and the second duration is in the range of about 12 days to about 1,900 days. In some embodiments, the first duration is in the range of about 13 days to about 278 days, and the second duration is in the range of about 66 days to about 1,900 days. In some embodiments, the first duration is in the range of about 29 days to about 278 days, and the second duration is in the range of about 180 days to about 1,900 days. In some embodiments, the first duration is about 30 days, and the second duration is about 200 days.

[0030] In some embodiments, the first rate, in tons per day, is in the range of about 0.1% to about 2% of the first total amount of free-phase CO2 injected over multiple injection cycles, and the second rate, in tons per day, is in the range of about 0.8% to about 2.5% of the second total amount of water injected over multiple injection cycles. In some embodiments, the first rate is in the range of about 0.1% to about 0.6% of the first total amount, and the second rate is in the range of about 1.2% to about 2.5%. In some embodiments, the first rate is in the range of about 0.001% to about 80% of the first total amount, and the second rate is in the range of about 0.01% to about 80% of the second total amount. In some embodiments, the first rate is in the range of about 0.001% to about 80% of the first total amount. In some embodiments, the first rate is in the range of about 0.001% to about 50% of the first total amount. In some embodiments, the first rate is in the range of about 0.001% to about 33% of the first total amount. In some embodiments, the first total amount of free-phase CO2 injected over multiple injection cycles is about 1 Mt. In some embodiments, the first total amount is about 2 Mt. In some embodiments, the first total amount is in the range of about 100 tons to about 1 Mt. In some embodiments, the first total amount is in the range of about 200 tons to about 2 Mt. In some embodiments, the first total amount is in the range of about 100 tons to about 3 Mt.

[0031] In some embodiments, the first rate is in the range of about 10 tons per day to about 5,879 tons per day, and the second rate is in the range of about 1,500 tons per day to about 25,000 tons per day. In some embodiments, the first rate is in the range of about 1,500 tons per day to about 20,548 tons per day, and the second rate is in the range of about 12,500 tons per day to about 25,000 tons per day. In some embodiments, the first rate is in the range of about 1,015 tons per day to about 20,548 tons per day, and the second rate is in the range of about 4,284 tons per day to about 25,000 tons per day. In some embodiments, the first rate is in the range of about 1,500 tons per day to about 5,879 tons per day, and the second rate is in the range of about 12,500 tons per day to about 25,000 tons per day. In some embodiments, the first rate is in the range of about 1,500 tons per day to about 2,833 tons per day, and the second rate is in the range of about 12,500 tons per day to about 25,000 tons per day. In some embodiments, the first rate is about 2,833 tons per day, and the second rate is about 12,500 tons per day.

[0032] In some embodiments, the first rate is based, at least in part, on a first total amount, in tons per day, of free-phase CO2 injected over multiple injection cycles. For example, in one embodiment, the first total amount is about 1,000 tons per day, and the first rate, in tons per day, is about 0.001% to about 80% of the first total amount, i.e., in a range from about 0.01 tons per day to about 800 tons per day. In another exemplary embodiment, the first total amount is about 5 Mt, and the first rate is in a range from about 5,000 tons per day to about 4 Mt per day.

[0033] In some embodiments, the ratio of the second amount to the first amount is in the range of about 0.5 to about 242. In some embodiments, the ratio of the second amount to the first amount is less than 30. In some embodiments, the ratio of the second amount to the first amount is in the range of about 13 to about 242. In some embodiments, the ratio of the second amount to the first amount is in the range of about 27 to about 242. In some embodiments, the ratio of the second amount to the first amount is about 27.1. In some embodiments, the ratio of the second amount to the first amount is in the range of about 0.1 to about 35.

[0034] In some embodiments, the ratio of the second speed to the first speed is in the range of about 0.6 to about 16.7. In some embodiments, the ratio of the second speed to the first speed is in the range of about 2 to about 17. In some embodiments, the ratio of the second speed to the first speed is in the range of about 4 to about 17. In some embodiments, the ratio of the second speed to the first speed is about 4.4. In some embodiments, the ratio of the second speed to the first speed is in the range of about 0.1 to about 17.

[0035] In some embodiments, the ratio of the second duration to the first duration is in the range of about 0.3 to about 15.2. In some embodiments, the ratio of the second duration to the first duration is in the range of about 5 to about 16. In some embodiments, the ratio of the second duration to the first duration is in the range of about 2 to about 10. In some embodiments, the ratio of the second duration to the first duration is about 6.7. In some embodiments, the ratio of the second duration to the first duration is in the range of about 0.1 to about 16.

[0036] In some embodiments, at 150, method 100 includes monitoring mineralization of injected CO at the siliceous site over a predetermined time period. In some embodiments, the predetermined time period is in a range from about 0 years to about 40 years. In some embodiments, the predetermined time period is about 5 years. In some embodiments, the predetermined time period is about 40 years. In some embodiments, the predetermined time period is greater than 40 years.

[0037] As shown in FIG. 2 , a method for designing a strategy for alternatingly injecting CO2 and water and capturing and mineralizing the CO2 in a rock reservoir is generally designated by the numeral 200. At 210, method 200 includes selecting an injection reservoir. As discussed above, in some embodiments, the injection reservoir is a rock reservoir, such as a mafic or ultramafic silicate rock reservoir. In some embodiments, the mafic silicate rock reservoir is basaltic. At 220, method 200 includes developing a rock reservoir model based on geological and geophysical data at or near the rock reservoir. In some embodiments, the silicate rock reservoir model is a geological earth model derived from field data acquired at or near an injection point in the rock reservoir. As used herein, the term “injection point” refers to a location in the rock reservoir where CO2 and / or water are injected into the rock reservoir. In some embodiments, the CO2 and water are injected through the same injection point. In some embodiments, the CO2 is injected through a first injection point and the water is injected through a second injection point. In some embodiments, each CO2 injection cycle is through a different injection point, such that the rock reservoir includes multiple CO2 injection points. In some embodiments, each water injection cycle is through a different injection point, such that the rock reservoir includes multiple water injection points. Thus, the disclosed subject matter is not limited to any particular quantity and sequence of injection points, so long as CO2 and water are injected alternately into the rock reservoir.

[0038] At 230, method 200 includes selecting an amount of CO to be injected. In some embodiments, the amount of CO to be injected is about 1 million metric tons. In some embodiments, the CO is free-phase CO. In some embodiments, the free-phase CO is in supercritical form. In some embodiments, the CO is pure-phase supercritical CO. At 240, method 200 includes selecting an amount of water to be injected. In some embodiments, the amount of water to be injected is based at least in part on the selected amount of CO to be injected. In some embodiments, the water is freshwater. In some embodiments, the water is seawater or saltwater. In some embodiments, the water is saturated with dissolved CO. In some embodiments, the water is sourced from, e.g., extracted from, a rock reservoir to help manage reservoir pressure and / or to reduce water requirements during injection.

[0039] At 250, method 200 includes selecting characteristics associated with the injection point of the rock reservoir. In some embodiments, as shown and discussed in further detail below, the injection point characteristics include injection depth, injection point porosity, injection point permeability, temperature, pressure, rock reservoir composition, rock reservoir geologic age, and water depth.

[0040] At 260, method 200 includes modeling the effect of a plurality of injection parameters on capture and mineralization efficiency in the rock reservoir. In some embodiments, modeling the effect of injection parameters on capture and mineralization efficiency takes into account characteristics of the injection site in the rock reservoir, as discussed in more detail below. In some embodiments, the plurality of injection parameters includes a plurality of injection cycles, each injection cycle including a first injection of CO2 and a second injection of water, a ratio of an amount of water injected to an amount of CO2 injected, a ratio of an injection rate of water to an injection rate of CO2, and a ratio of a water injection cycle duration to a CO2 injection cycle duration. In some embodiments, the plurality of injection parameters includes the injection parameters and their respective ratios, ranges, and values ​​discussed above with respect to method 100.

[0041] In some embodiments, the total number of the plurality of infusion cycles is in the range of about 2 to about 400. In some embodiments, the total number of the plurality of infusion cycles is in the range of about 2 to about 45. In some embodiments, the total number of the plurality of infusion cycles is about 2. In some embodiments, the total number of the plurality of infusion cycles is about 3. In some embodiments, the total number of the plurality of infusion cycles is greater than about 45. In some embodiments, the total number of the plurality of infusion cycles is in the range of about 20 to about 45. In some embodiments, the total number of the plurality of infusion cycles is in the range of about 23 to about 45. In some embodiments, the total number of the plurality of infusion cycles is in the range of about 37 to about 45. In some embodiments, the total number of the plurality of infusion cycles is about 23.

[0042] In some embodiments, the ratio of the amount of water injected to the amount of CO2 injected is in the range of about 0.5 to about 242. In some embodiments, the ratio of the amount of water injected to the amount of CO2 injected is less than 30. In some embodiments, the ratio of the amount of water injected to the amount of CO2 injected is in the range of about 13 to about 242. In some embodiments, the ratio of the amount of water injected to the amount of CO2 injected is in the range of about 27 to about 242. In some embodiments, the ratio of the amount of water injected to the amount of CO2 injected is about 27.1.

[0043] In some embodiments, the ratio of the water injection rate to the CO2 injection rate is in the range of about 0.60 to about 16.7. In some embodiments, the ratio of the water injection rate to the CO2 injection rate is in the range of about 2 to about 17. In some embodiments, the ratio of the water injection rate to the CO2 injection rate is in the range of about 4 to about 17. In some embodiments, the ratio of the water injection rate to the CO2 injection rate is about 4.4.

[0044] In some embodiments, the ratio of water injection cycle duration to CO2 injection cycle duration is in the range of about 0.3 to about 15.2. In some embodiments, the ratio of water injection cycle duration to CO2 injection cycle duration is in the range of about 5 to about 16. In some embodiments, the ratio of water injection cycle duration to CO2 injection cycle duration is in the range of about 2 to about 10. In some embodiments, the ratio of water injection cycle duration to CO2 injection cycle duration is about 6.7.

[0045] In some embodiments, the injection parameters further include a first rate of CO injection per injection cycle and a second rate of water injection per injection cycle. In some embodiments, the first rate is in the range of about 0.1% to about 2% of a first total amount of free-phase CO injected over the multiple injection cycles, in tons per day, and the second rate is in the range of about 0.8% to about 2.5% of a second total amount of water injected over the multiple injection cycles, in tons per day. In some embodiments, the first rate is in the range of about 0.1% to about 0.6% of the first total amount, and the second rate is in the range of about 1.2% to about 2.5%. In some embodiments, the first rate is in the range of about 0.001% to about 80% of the first total amount, and the second rate is in the range of about 0.01% to about 80% of the second total amount. In some embodiments, the first rate is in the range of about 0.001% to about 80% of the first total amount. In some embodiments, the first rate is in the range of about 0.001% to about 50% of the first total amount. In some embodiments, the first rate is in the range of about 0.001% to about 33% of the first total amount. In some embodiments, the first total amount of free-phase CO2 injected over multiple injection cycles is about 1 Mt. In some embodiments, the first total amount is about 2 Mt. In some embodiments, the first total amount is in the range of about 100 tonnes to about 1 Mt. In some embodiments, the first total amount is in the range of about 200 tonnes to about 2 Mt. In some embodiments, the first total amount is in the range of about 100 tonnes to about 3 Mt.

[0046] In some embodiments, the first rate is in the range of about 10 tons per day to about 5,879 tons per day, and the second rate is in the range of about 1,500 tons per day to about 25,000 tons per day. In some embodiments, the first rate is in the range of about 1,500 tons per day to about 20,548 tons per day, and the second rate is in the range of about 12,500 tons per day to about 25,000 tons per day. In some embodiments, the first rate is in the range of about 1,015 tons per day to about 20,548 tons per day, and the second rate is in the range of about 4,284 tons per day to about 25,000 tons per day. In some embodiments, the first rate is in the range of about 1,500 tons per day to about 5,879 tons per day, and the second rate is in the range of about 12,500 tons per day to about 25,000 tons per day. In some embodiments, the first rate is in the range of about 1,500 tons per day to about 2,833 tons per day, and the second rate is in the range of about 12,500 tons per day to about 25,000 tons per day. In some embodiments, the first rate is about 2,833 tons per day, and the second rate is about 12,500 tons per day.

[0047] In some embodiments, the first rate is based, at least in part, on a first total amount, in tons per day, of free-phase CO2 injected over multiple injection cycles. For example, in one embodiment, the first total amount is about 1,000 tons per day, and the first rate, in tons per day, is about 0.001% to about 80% of the first total amount, i.e., in a range from about 0.01 tons per day to about 800 tons per day. In another exemplary embodiment, the first total amount is about 50 Mt, and the first rate is in a range from about 500 tons per day to about 40 Mt per day.

[0048] In some embodiments, the injection parameters further include a first duration of CO2 injection per injection cycle and a second duration of water injection per injection cycle. In some embodiments, the first duration is in the range of about 1 day to about 416 days, and the second duration is in the range of about 1 day to about 1,900 days. In some embodiments, the first duration is in the range of about 5 days to about 416 days, and the second duration is in the range of about 12 days to about 1,900 days. In some embodiments, the first duration is in the range of about 13 days to about 278 days, and the second duration is in the range of about 66 days to about 1,900 days. In some embodiments, the first duration is in the range of about 29 days to about 278 days, and the second duration is in the range of about 180 days to about 1,900 days. In some embodiments, the first duration is about 30 days, and the second duration is about 200 days.

[0049] At 270, method 200 includes defining an injection strategy by defining a plurality of injection parameters to improve capture and mineralization efficiency within the rock reservoir. In some embodiments, defining step 270 further includes defining a plurality of injection parameters to improve dissolution capture. In some embodiments, defining step 270 further includes defining a plurality of injection parameters to reduce energy consumption for the injection strategy. In some embodiments, defining step 270 further includes defining a plurality of injection parameters to reduce water consumption for the injection strategy. Further details on how an injection strategy is defined are discussed below with reference to exemplary embodiments. [Example]

[0050] In some embodiments, the simulator's Earth model was designed over a cylindrical coordinate system. Geochemistry was modeled using the ECKE-Chem reactive transport module and the LLNL V8 R6 thermodynamic database. Different WAG scenarios were simulated under a range of input parameters for injection at Cascadia, Louisville, and Wallula. A total of 1 million metric tons ("Mt") of injected carbon dioxide was simulated in the reservoirs at the Cascadia and Louisville sites and monitored for 40 years. At these sites, the basaltic reservoirs were initially saturated with seawater of the same composition as the basaltic crustal fluids observed elsewhere in the region. Table 1 below summarizes the injection site characteristics associated with these sites. [Table 1]

[0051] In some embodiments, three different injection scenarios were simulated: 1) free-phase CO2 alone (also referred to herein as "scCO2 alone"), 2) a scenario in which CO2 is completely dissolved in seawater, and 3) a scenario in which CO2 and seawater are injected alternately ("WAG"). In these simulations, the seawater is assumed to contain 3.5% salt by weight. The WAG scenario was designed to improve mineralization. Therefore, the relative performance of the individual simulation scenarios is evaluated based on the mineralization efficiency, which is defined as follows:

number

[0052] In some embodiments, the injection parameters for the WAG injection scenario are determined by four main variables: WAG "," "R WAG ","L WAG " and "N". WAGは , refers to the ratio between the total mass of water injected and the total mass of CO2 injected, and therefore estimates the water consumption for a given scenario. WAG is the ratio of the water injection rate to the CO2 injection rate, and L WAG is the ratio of the water injection cycle length to the CO2 injection cycle length (i.e., cycle duration). N corresponds to the total number of WAG cycles in each scenario. To evaluate the relative control of these WAG injection parameters on mineralization at the Cascadia site, simulations were designed to generate a range of values ​​for each variable, and results were recorded after each simulation, as shown in Table 2 of Figure 6. The variable W WAG , R WAG , L WAG The results were interpreted to determine which values ​​of N and W yielded the highest mineralization efficiency, which would improve the injection parameters for mineralization. In some embodiments, given practical considerations regarding water use, the W of the simulated scenarios was WAG is less than 30.

[0053] In some embodiments, a first-order sensitivity analysis was performed using data from the Cascadia site to constrain the reservoir properties that have the greatest impact on mineralization. WAG , R WAG , L WAG A subset of WAG scenarios with varying values ​​for , and N were repeatedly simulated with incremental changes in permeability, porosity, and injected water composition (seawater vs. freshwater) to higher and lower values, as shown in Table 3 below. At the Louisville Submarine Volcano and Wallula sites, aqueous-dissolved injection and scThe same subset of WAG scenarios was simulated, along with CO2-only injection, which showed significant improvements. Note that some injection scenarios resulted in overpressure, and where necessary, the maximum allowable headwell pressure was adjusted slightly to allow injection. At Wallula, the injection size was reduced because a small change in the maximum allowable headwell pressure did not result in convergence of the model. Four parameters (W WAG , R WAG , L WAG , and N) were consistent for a given scenario across all three geological models, despite the smaller injection size at Wallula. [Table 3]

[0054] Table 2 in the figure shows the results of 1 Mt CO2 injection over 40 years at the Cascadia site. With one exception, Cascadia's 40-year mineralization efficiency is lowest for the scCO2-only scenario, at 41.8%. For the WAG scenarios, mineralization efficiency results range from 41.3% to 99.6%, while the seawater dissolution scenario has the highest mineralization efficiency after 40 years, at 99.8%. The highest mineralization efficiency in the WAG scenario is due to the high W WAG In low water scenarios, mineralization efficiency generally corresponds to that with L WAG To evaluate the improvement in mineralization efficiency using WAG injection relative to the scCO2-only scenario over a given period, the performance of the WAG injection scenario was defined using the dimensionless ratio IF as follows:

number

[0055] At the Cascadia site, the WAG injection scenario improved mineralization efficiency by an average IF of 1.68 ± 0.38 (n = 51) after 40 years, with the aqueous solution injection scenario showing the highest IF of 2.39 (Table 2 in Figure 6). However, at the Louisville and Wallula sites, the optimized WAG injection scenario produced higher IF values ​​than the aqueous solution approach, as shown in Table 5 in Figure 8. At the Louisville site, 40-year mineralization efficiencies ranged from 53.3% for the scCO2-only scenario to 99.0% for the WAG scenario, demonstrating an overall higher mineralization efficiency than that observed at Cascadia. Unlike Cascadia, where aqueous solution injection produced the best results, the improved WAG injection at both Louisville and Wallula produced the highest 40-year mineralization efficiency results (99.0% and 88.0%, respectively). WAG injection improved mineralization most at the Wallula site, with the improved WAG scenario more than tripling the 40-year mineralization efficiency over scCO2 alone (IF=3.32), and the WAG scenario also achieved approximately 10% more mineralization than the aqueous solution approach (Table 5 in Figure 8). Mineralization efficiency at Wallula was generally much lower than at the offshore sites, with the lowest being 26.6% after 40 years for scCO2 alone. The ScCO2 alone injection scenario resulted in the greatest variation in mineralization efficiency among the three sites.

[0056] Figure 3 shows a graph of the mass of CO2 mineralized versus time for selected simulations of a 1 Mt CO2 injection into the Cascadia Basin. The second Y-axis shows the fraction of injected CO2 that was mineralized throughout the length of the simulation. Varying W WAG WAG injection with WAG values ​​(denoted SC) resulted in significantly more mineralization than supercritical injection alone at this location. Seawater-dissolved injection (denoted WD) resulted in significantly more mineralization than WAG injection alone at this location. WAG = 30. W WAGSimulations with IF = 27 resulted in the fastest mineralization, as indicated by the steep slope after about 4.5 years of injection. As shown in Table 2 and Figure 3 of Figure 6, improved WAG injection with a water-to-CO2 ratio of 4 nearly doubled the amount of CO2 mineralized after 5 years (IF = 2) and improved mineralization efficiency after 40 years from 41% to 71%. In some embodiments, as shown in Table 2 of Figure 6, W WAG The injection scenario >30 results in the fastest mineralization.

[0057] In some embodiments, WAG injection is performed at offshore sites in the Louisville submarine volcano and Cascadia Basin to evaluate site-specific factors that may affect mineralization efficiency during WAG injection. WAG A subset of scenarios with various values ​​of σ were simulated. A summary of the results is shown in Table 5 of Figure 8. WAG injection reduced site-specific variability in mineralization efficiency, as shown in Figure 4. Figure 4 is a graph showing the mass of CO2 mineralized over time for three injection strategies simulating 1 Mt of CO2 injection into both the Cascadia (solid line) and Louisville (dashed line) sites. The secondary Y-axis shows the fraction of injected CO2 mineralized throughout the length of the simulation. Differences between sites are more pronounced for scCO2-only injection (denoted SC) and water-dissolved injection (denoted WD) than for WAG injection (denoted WAG). Generally, mineralization efficiency was highest at Louisville, which is unexpected given that the Cascadia site is hotter and contains younger basalt (Table 1). Although reaction rates were assumed to be the same at both offshore sites, the target injection zone at the Louisville submarine volcano contained a higher proportion of olivine, further highlighting the primary control of mineral composition on mineralization efficiency. This, along with higher porosity, contributed to the result that scCO2-only injection was most effective at the Louisville site, resulting in lower IF values ​​for the WAG scenario simulated here, as shown in Figure 5. Figure 5 shows the W WAGFigure 1 shows the improvement coefficients for a subset of simulated WAG scenarios at all three locations against R. There is a strong correlation for all three locations, with WAG at Wallula showing the strongest improvement (R 2 =0.95), followed by Cascadia (R 2 =0.86), Louisville (R 2 = 0.81). Given the low mineralization efficiency over 40 years for the 100,000t scCO2 injection alone at Wallula, subsequent WAG simulations at this site correspondingly yielded the highest IF values, as shown in Figure 5. At this site, and potentially in other continental flood basalt provinces, WAG injection dramatically improves mineralization. For example, the WAG injection at Wallula WAG The = 7 injection scenario doubles the amount of mineralized CO2 at both 5 and 40 years relative to the scCO2-only scenario (Table 5 in Figure 8). The performance of WAG injection is comparable to that of WAG injection for all three sites. WAG The relationship increases linearly with , but is strongest at the Wallula site (Fig. 5, R 2= 0.95). Therefore, in generally less favorable reservoirs (low reactive phases, low temperatures, low permeability), the WAG injection strategy significantly improves mineralization efficiency.

[0058] Accordingly, embodiments of the disclosed subject matter are directed to a method for carbon storage in basalt using a WAG injection strategy that demonstrates the potential for large-scale mineral storage in both onshore and offshore rock reservoirs. The WAG method disclosed herein dramatically improves CO2 mineralization in basalt over free-phase-only injection, demonstrating that a high water-to-gas ratio and short CO2 cycle contribute to rapid mineralization. While simulations at the Louisville site demonstrated the highest mineralization efficiency, the Wallula site showed the greatest improvement in mineralization efficiency with the WAG strategy over free-phase alone. This suggests that for sites with less favorable characteristics for mineralization (e.g., low temperature, low velocity, low permeability), WAG injection significantly improves mineralization efficiency. Therefore, implementing a WAG strategy expands the geographic range in which mineralization projects are feasible. Furthermore, the disclosed subject matter demonstrates that WAG is a method for improving rapid geochemical capture during free-phase CO2 injection for geological storage.

[0059] As will be apparent to those skilled in the art, various modifications, adaptations, and variations of the specific disclosures set forth above can be made without departing from the scope of the technology claimed herein. Various features or elements of the technology described herein can be combined in different ways from the specific examples described or claimed herein without departing from the scope of the technology. In other words, any element or feature may be combined with any other element or feature in different embodiments unless there is an obvious or inherent incompatibility between them or unless it is expressly excluded. The term "and / or" refers to any one of the items, any combination of the items, or all of the items with which the term is associated. The phrase "one or more" is readily understood by those skilled in the art, particularly when read in the context of its usage. Each numerical value or measurement herein is modified by the term "about." The term "about" can refer to a variation of ±5%, ±10%, ±20%, or ±25% of the stated value. For example, "about 50" percent may have a variation of 45 to 55 percent in some embodiments. With respect to a range of integers, the term "about" can include one or two integers greater than and / or less than the recited integer at either end of the range. Unless otherwise indicated herein, the term "about" is intended to include values ​​and ranges adjacent to the recited range that are equivalent in terms of the functionality of the composition or embodiment.

[0060] While the present invention has been described and illustrated with respect to exemplary embodiments thereof, it should be understood by those skilled in the art that the foregoing and various other modifications, omissions, and additions may be made therein and thereto without departing from the spirit and scope of the invention.

Claims

1. CO in rock reservoirs ２ 1. A method for capturing and mineralizing a first amount of free-phase CO at a first rate for a first duration; ２ into the rock reservoir; injecting a second amount of water into the rock reservoir at a second rate for a second duration; Alternating between at least one of the injection steps over a plurality of injection cycles; A method comprising:

2. The CO ２ is trapped within the aqueous phase and / or mineralized within the rock reservoir.

3. The method of claim 1 , wherein the rock reservoir is basaltic, silicate, mafic, ultramafic, sedimentary, or a combination thereof.

4. The free phase CO ２ is supercritical CO ２ The method of claim 1, wherein

5. The method of claim 1 , wherein the water is freshwater, seawater, saltwater, or a combination thereof.

6. The method of claim 1 , wherein the water is sourced from the rock reservoir.

7. 10. The method of claim 1, wherein the total number of the plurality of injection cycles is in the range of about 2 to about 45.

8. 10. The method of claim 1, wherein the first duration is in the range of about 1 day to about 416 days and the second duration is in the range of about 1 day to about 1,900 days.

9. the first rate being in tons per day of free phase CO injected over the plurality of injection cycles; ２ and the second rate, in tons per day, is within the range of about 0.001% to about 80% of the second total amount of water injected over the plurality of injection cycles.

10. The method of claim 1 , wherein the ratio of the second amount to the first amount is less than 30.

11. The method of claim 1, wherein the ratio of the second speed to the first speed is in the range of about 0.60 to about 16.

7.

12. 10. The method of claim 1, wherein the ratio of the second duration to the first duration is in the range of about 0.3 to about 15.

2.

13. CO ２ and water are injected alternately to generate CO in the rock reservoir. ２ 1. A method for designing a strategy for capturing and mineralizing developing a model of the rock reservoir based on geological and geophysical data at or near the rock reservoir; CO to be injected ２ Selecting the amount of Selecting the amount of water to be injected; selecting a characteristic associated with an injection point in the rock reservoir; modeling the effects of a plurality of injection parameters on capture and mineralization efficiency in the rock reservoir based at least in part on characteristics of the selected injection site, the plurality of injection parameters comprising: A plurality of injection cycles, each injection cycle comprising: ２ and a second injection of water; The injected CO ２ the ratio of the amount of water injected to the amount of water The CO ２ the ratio of the injection rate of the water to the injection rate of the The CO ２ a ratio of the water injection cycle duration to the injection cycle duration of the water; defining an injection strategy by defining the plurality of injection parameters to improve capture and mineralization efficiency, reduce energy consumption, and reduce water consumption; A method comprising:

14. 14. The method of claim 13, wherein the total number of the plurality of injection cycles is in the range of about 2 to about 400.

15. The injected CO ２ 14. The method of claim 13, wherein the ratio of the amount of water injected to the amount of water is in the range of about 0.5 to about 242.

16. The CO ２ the ratio of the injection rate of the water to the injection rate of the CO ２ 14. The method of claim 13, wherein the ratio of the injection cycle duration of the water to the injection cycle duration of the saturation agent, respectively, is in the range of about 0.3 to about 16.

7.

17. 14. The method of claim 13, wherein the rock reservoir is basaltic, silicate, mafic, ultramafic, sedimentary, or a combination thereof.

18. The CO ２ Free Phase CO ２ 14. The method of claim 13, wherein the water is fresh water, sea water, salt water, water sourced from the rock reservoir, or a combination thereof.

19. 14. The method of claim 13, wherein the injection site characteristics include injection depth, injection site porosity, injection site permeability, temperature, pressure, rock reservoir composition, rock reservoir geological age, and water depth.

20. CO in rock reservoirs ２ 1. A method for capturing and mineralizing A first amount of supercritical CO 2 is injected at a first rate for a first duration. ２ into the rock reservoir; injecting a second amount of water into the rock reservoir at a second rate for a second duration, wherein the water is fresh water, seawater, salt water, water sourced from the rock reservoir, or a combination thereof; and alternatingly repeating at least one of the injection steps over a plurality of injection cycles; a total number of the plurality of injection cycles ranging from about 1 to about 400; a ratio of the second amount to the first amount ranging from about 0.1 to about 35; a ratio of the second rate to the first rate ranging from about 0.1 to about 17; and a ratio of the second duration to the first duration ranging from about 0.1 to about 16.

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