A method of preventing leakage in a carbon dioxide geological storage process

Abstract

The application provides a method for preventing leakage in a carbon dioxide geological storage process, comprising the following steps: preparing a sulfate-reducing bacteria culture medium; extracting sulfate-reducing bacteria, culturing the sulfate-reducing bacteria in the sulfate-reducing bacteria culture medium at 28-38 DEG C to obtain cultured sulfate-reducing bacteria; for a stratum region with a sulfate mineral content of no less than 5 wt.%, exploring the stratum, selecting a stratum with a high sulfate mineral content, injecting the cultured sulfate-reducing bacteria into fractures in the stratum through a filling pipe, and standing; for a cap rock region with a sulfate mineral content of less than 5 wt.%, mixing sulfate and the cultured sulfate-reducing bacteria, standing to obtain a mixed solution, and then injecting the mixed solution into fractures in the stratum, and standing. The technical scheme of the application forms a cemented filling material through the interaction between microorganisms and stratum minerals, and can effectively seal fractures around an injection well in a micro view.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide sequestration technology, and more particularly to a method for preventing leakage during the geological sequestration of carbon dioxide. Background Technology

[0002] In recent years, with the rapid development of human society, resources and the environment have gradually come into focus. Due to the overuse of resources, carbon emissions are also increasing rapidly, and the global temperature is gradually rising. The increase in carbon emissions has had a huge impact on the environment, leading to problems such as global climate change, sea-level rise, and frequent extreme weather events. As a greenhouse gas, carbon dioxide has become a key focus of human concern.

[0003] Geospatial carbon dioxide (CO2) storage is a technology that stores large quantities of carbon dioxide underground, aiming to mitigate climate change and reduce CO2 emissions. Currently, after years of research and experimentation, this technology is considered one of the most promising CO2 emission reduction technologies. Geospatial carbon dioxide storage involves injecting carbon dioxide gas into underground rock formations, storing it there long-term to reduce the concentration of carbon dioxide in the atmosphere. Typically, the injected carbon dioxide is compressed into a liquid or supercritical state for better storage. This process requires selecting a suitable rock formation, such as sandstone, salt rock, or shale, which can ensure the safe sequestration of carbon dioxide without significant leakage.

[0004] In carbon dioxide geological storage, leakage of the stored carbon dioxide from the caprock or injection well is inevitable. While caprock leakage is slow, injection well leakage is rapid, but both are major modes of carbon dioxide leakage. Therefore, preventing carbon dioxide leakage is crucial in carbon dioxide geological storage. However, caprock leakage currently occurs frequently. Summary of the Invention

[0005] To address the above technical problems, this invention discloses a method for preventing leakage during the geological storage of carbon dioxide. This method considers factors such as the living environment of microorganisms, the chemical reaction between microorganisms and minerals, the filling of pores in the formation by reaction products, and the activity of microorganisms. This reduces the leakage of carbon dioxide in the reservoir and avoids pollution of groundwater and the underground environment caused by carbon dioxide leakage.

[0006] The technical solution adopted by this invention is as follows:

[0007] A method for preventing leakage during carbon dioxide geological storage includes the following steps:

[0008] Step S1: Prepare a culture medium for sulfate-reducing bacteria;

[0009] Step S2: Extract sulfate-reducing bacteria and culture them in a sulfate-reducing bacteria culture medium at 28~38℃ to obtain well-cultured sulfate-reducing bacteria;

[0010] Step S3: For strata with a sulfate mineral content of not less than 5 wt.%, i.e., strata with a relatively high sulfate mineral content, explore the strata and select strata with a relatively high sulfate mineral content (here, "relatively high" is used in comparison; two locations are selected for comparison, and the one with the higher content is considered "relatively high"). For example, if the sulfate content exceeds 10 wt.% of the strata (in some geological conditions, the sulfate content may reach 20%–40%), and the strata are relatively close to the carbon dioxide reservoir, inject cultured sulfate-reducing bacteria into the fractures of the strata through a filling pipe, and let it stand. Further, select strata that are relatively close to the carbon dioxide reservoir; here, "relatively close" is used in comparison. The strata closest to the furthest strata are chosen for ease of implementation.

[0011] For caprock areas with sulfate mineral content less than 5 wt.%, that is, strata with few or even almost no sulfate minerals, sulfate and cultured sulfate-reducing bacteria are mixed, allowed to stand to obtain a mixture, and then the mixture is injected into the fissures of the caprock and allowed to stand; wherein, the mass ratio of sulfate to cultured sulfate-reducing bacteria is 1:1-10.

[0012] Sulfate-reducing bacteria react with sulfate to produce a cementing substance that seals cracks, thereby preventing carbon dioxide leakage.

[0013] The sulfate-reducing bacteria culture medium can be any existing culture medium for culturing sulfate-reducing bacteria.

[0014] Most of the sulfate-reducing bacteria cannot grow using molecular oxygen as an electron acceptor, thus they are anaerobic bacteria. After being cultured, these sulfate-reducing bacteria are added to the fissures of sulfate mineral strata. The microbial sulfate-reducing bacteria react with the strata minerals through a series of chemical reactions, yielding sulfides as the final product. These sulfides then react with carbonates or other minerals in the strata to form sulfide minerals, which possess cementing properties, thereby preventing carbon dioxide leakage.

[0015] As a further improvement of the present invention, in step S2, the temperature of the culture medium is 30-35℃.

[0016] Sulfate-reducing bacteria (SRB) are significantly affected by temperature. Temperature is the main environmental parameter influencing anaerobic sulfate reduction, directly determining the metabolic activity and growth rate of SRB. SRB are classified into mesophilic and thermophilic bacteria. Most SRB are mesophilic, with an optimum temperature generally around 30℃, and optimal growth occurring between 28-38℃. For mesophilic bacteria, temperatures between 30-35℃ have little effect on SRB activity, but below 28℃, SRB activity is inhibited, and below 20℃, SRB activity is strongly inhibited.

[0017] As a further improvement of the present invention, the sulfate mineral formation includes a gypsum layer or a hard, brittle rock layer.

[0018] As a further improvement of the present invention, the pH value of the sulfate-reducing bacteria culture medium is 6.48-7.43. The metabolism of the sulfate-reducing bacteria is affected by pH. The range of pH at which the sulfate-reducing bacteria are not inactivated is 5.0-9.0. They have better activity in the neutral pH range, and the sulfate reduction effect is best when the pH value is between 6.48 and 7.43.

[0019] As a further improvement of the present invention, the culture medium is prepared by the following steps:

[0020] Dissolve potassium dihydrogen phosphate, ammonium chloride, magnesium chloride hexahydrate, sodium sulfate, calcium chloride, sodium D-lactic acid solution, yeast extract, ferrous sulfate heptahydrate, and sodium thioglycolate in water to achieve the following concentrations: potassium dihydrogen phosphate 0.1-1 g / L, ammonium chloride 0.4-1.5 g / L, magnesium chloride hexahydrate 1.0-3.0 g / L, sodium sulfate 0.5-2.0 g / L, calcium chloride 0.01-0.1 g / L, sodium D-lactic acid solution 0.5-1.5 g / L, yeast extract 0.5-1.5 g / L, ferrous sulfate heptahydrate 0.1-1.0 g / L, and sodium thioglycolate 0.05-0.2 g / L. Adjust the pH to 6.8-7.4, pour the solution into an anaerobic culture flask, add ascorbic acid, seal the flask, and sterilize at high temperature.

[0021] As a further improvement of the present invention, the culture medium is prepared by the following steps: glucose, KH2PO4, K2HPO4, MgCl2•6H2O, FeCl2•12H2O, NH4Cl, and NaHS are dissolved in water to achieve the following concentrations: glucose 40-60 g / L, KH2PO4 0.5-1.5 g / L, K2HPO4 0.5-1.5 g / L, MgCl2•6H2O 0.5-1.5 g / L, FeCl2•12H2O 0.005-0.02 g / L, NH4Cl 0.2-1.0 g / L, and NaHS 4-6 g / L. The pH is adjusted to 6.8-7.2, and then the medium is sterilized at high temperature.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] First, the technical solution of this invention involves injecting sulfate-reducing bacteria into the fractures. Under the action of microorganisms, a spontaneous reaction occurs to seal the fractures around the injection well. That is, cemented backfill material is prepared through the interaction between microorganisms and formation minerals. This not only utilizes existing mineral reaction products to fill pores and reduce carbon dioxide leakage, but also avoids problems such as groundwater and surrounding environmental pollution caused by carbon dioxide leakage. This further improves the backfilling mining technology in carbon dioxide geological sequestration, thereby achieving the goal of truly "living off the mountains and water" in green and environmentally friendly mine backfilling. Moreover, it is simple to operate and highly efficient.

[0024] Secondly, unlike traditional sealing materials such as lime slurry, the technical solution of this invention first utilizes the existing mineral components in the caprock, and achieves the filling of fractures through chemical precipitation reaction catalyzed by sulfate-reducing bacteria; this method can microscopically seal the fractures around the injection well, achieving efficient sealing.

[0025] Third, unlike traditional sealing materials such as cement slurry that are corroded by carbon dioxide, which cause leakage, this invention uses precipitates such as metal compounds that are difficult to be corroded by carbon dioxide for sealing. These precipitates are chemically stable and can maintain long-term effective sealing in a carbon dioxide geological storage environment.

[0026] Fourth, compared with other microorganisms such as methanogens, the sulfate-reducing bacteria used in the technical solution of this invention release more energy. The sulfate reduction reaction is easier to carry out than the methanogenic reaction. Moreover, when the proportion of sulfate ions in the formation is not high, the content of hydrogen sulfide produced is low. At this time, the sulfate-reducing bacteria react faster and have a greater competitive advantage than the methanogens in the chemical reaction between the two bacteria. Attached Figure Description

[0027] Figure 1 This is a flowchart illustrating the leakage prevention method during the geological storage of carbon dioxide according to an embodiment of the present invention.

[0028] Figure 2 This is a flowchart illustrating the sulfate-reducing bacteria reduction mechanism of the method for preventing leakage during carbon dioxide geological storage according to an embodiment of the present invention. Detailed Implementation

[0029] The preferred embodiments of the present invention will be described in further detail below.

[0030] A method for preventing leakage during carbon dioxide geological storage is described, with construction methods explained for strata with high sulfate content and strata with low or almost no sulfate content, respectively. Figure 1 As shown.

[0031] The specific steps for sulfate formations with high sulfate content are as follows:

[0032] Step S1: Prepare a culture medium for sulfate-reducing bacteria;

[0033] Step S2: Extract sulfate-reducing bacteria and culture them in a culture medium at 28-38°C;

[0034] Step S3: Explore the strata and identify suitable strata (high sulfate mineral content, close proximity to carbon dioxide reservoirs, and suitable environment).

[0035] Step S4: The sulfate-reducing bacteria in the culture medium are injected into the fissures of the suitable formation through the filling tube and left to stand.

[0036] The strata are composed of sulfate minerals, and the strata are characterized by a high proportion of sulfate minerals, such as gypsum layers and hard rock layers. The chemical formula of gypsum is CaSO4•2H2O, and that of hard rock is also CaSO4•2H2O. The sulfate content of both rock layers is approximately 30%.

[0037] For formations with few or even almost no sulfate components, the specific steps are as follows:

[0038] Step S1: Prepare a culture medium for sulfate-reducing bacteria;

[0039] Step S2: Extract sulfate-reducing bacteria and culture them in a culture medium at 28-38℃;

[0040] Step S3: Mix sulfate and cultured sulfate-reducing bacteria, and let stand to obtain a mixed solution; wherein the mass ratio of sulfate to cultured sulfate-reducing bacteria is 1:1-10.

[0041] Step S4: Inject the mixed solution into the cracks of the cap layer through the filling tube and let it stand.

[0042] like Figure 2 As shown, the reaction mechanism of sulfate-reducing bacteria is as follows: sulfate-reducing bacteria metabolism can be divided into two stages. In the first stage, under anaerobic conditions, organic carbon sources produce a small amount of ATP through substrate-level phosphorylation. The second stage involves SO42-. 2- The activation of ATP involves the reaction of sulfate and ATP to convert adenosine phosphate (APS) and pyrophosphate (PPI). PPI rapidly decomposes into inorganic PI, driving the reaction continuously to the right. APS further decomposes into sulfite (SO32-). 2- ) and adenosine monophosphate (AMP). Sulfite is dehydrated and converted to metabisulfite [S₂O₅] 2- [S2O5] 2-It is extremely unstable and quickly decomposes into the intermediate product dithionate [S₂O₄]. 2- [S2O4] 2- It then quickly transforms into [S3O6]. 2- It then further decomposes into thiosulfate [S₂O₃]. 2- and sulfites (SO3) 2- Thiosulfate is then converted into sulfite and the final product S through its own redox reaction. 2- S 2- It is excreted from the body and enters the surrounding environment. During the entire sulfate reduction process, SO4 is used. 2- It acts as a terminal electron acceptor, converting organic matter into both a carbon source and an electron donor for cellular synthesis, while simultaneously converting SO42-. 2- It is converted into sulfides.

[0043] Sulfate-reducing bacteria are highly sensitive to the toxicity of H2S. When the H2S concentration is 40-50 mg / L, the activity of sulfate-reducing bacteria is completely inhibited, and the loss of activity is irreversible after 3-6 hours. During the reduction process of sulfate-reducing bacteria, sulfides are continuously produced. These sulfides first combine with metal ions to form gelling substances, and then combine with hydrogen ions in the formation to form hydrogen sulfide. This hydrogen sulfide reacts with the sulfate-reducing bacteria, gradually slowing down the reduction process until it stops.

[0044] Furthermore, in anaerobic environments, sulfate-reducing bacteria are more advantageous than methanogens. When sulfate and fermentation products coexist, sulfate-reducing bacteria will compete with methanogens. It has been demonstrated that, from a thermodynamic and thermodynamic perspective, using acetate and H2 as electron donors is more favorable for sulfate-reducing bacteria. First, the energy released by sulfate reduction is greater than that released by methanogenesis, indicating that sulfate reduction is easier to carry out than methanogenesis. Second, these electrons have a lower Km (Michaelis constant) value, giving sulfate-reducing bacteria a greater kinetic advantage than methanogens. Example 1

[0045] This embodiment describes a leak prevention and sealing method for sulfate formations with high sulfate content. The specific steps are as follows:

[0046] (1) Add 0.5g of potassium dihydrogen phosphate, 1.0g of ammonium chloride, 2.0g of magnesium chloride hexahydrate, 1.0g of sodium sulfate, 0.05g of calcium chloride, 1.1g of D-lactic acid sodium solution, 1.0g of yeast extract, 0.5g of ferrous sulfate heptahydrate, and 0.1g of sodium thioglycolate to 1000mL of distilled water. After the above drugs are completely dissolved, adjust the pH to 6.8-7.4 with 2mol / L sodium bicarbonate solution. Then pour it into an anaerobic culture bottle, add 0.1g of ascorbic acid, wrap the bottle mouth with tin foil, and sterilize it in an autoclave at 121℃ for 20 minutes to prepare sulfate-reducing bacteria culture medium.

[0047] (2) Extract the sulfate-reducing bacteria, inactivate them, and then put them into the sulfate-reducing bacteria culture medium in step (1) for culture. The temperature of the culture medium is adjusted to 30℃.

[0048] (3) Explore the strata and measure the gypsum layer;

[0049] (4) The sulfate-reducing bacteria in the culture medium are injected into the fissures of the suitable stratum through the filling tube;

[0050] (5) Let stand and wait. The reaction product, sulfide, reacts with metal ions to form minerals that fill the pores.

[0051] When the reaction between sulfides and metal ions is delayed, sulfide ions combine with hydrogen ions in the formation to form hydrogen sulfide. The generated hydrogen sulfide will have a counteracting effect on sulfate-reducing bacteria, inhibiting their activity until the sulfate-reducing bacteria are inactivated.

[0052] After 7 weeks, the sulfate conversion rate reached 15 kg / m³. 3 / d, the average sulfate removal rate is 88%.

[0053] The sealing effect of this embodiment is at least 5% higher than that of conventional methods used in the prior art for sealing natural formations. Furthermore, the longer the sealing time, the more sulfide precipitates are produced, resulting in a better sealing effect. Example 2

[0054] (1) Enrichment and desulfurization experimental culture medium

[0055] 50g glucose, 1.0g KH2PO4, 1.0g K2HPO4, 0.8g MgCl2•6H2O, 0.01g FeCl2•12H2O, 0.4g NH4Cl, 5.0g NaHS, 1000mL distilled water, pH 6.8–7.2, sterilized at 115℃ for 30min.

[0056] Alternatively, the following culture medium can be used: 5.0g yeast extract, 10.0g peptone, 10.0g NaCl, 1000mL distilled water, pH 7.0, sterilized at 121℃ for 30min to prepare sulfate-reducing bacteria culture medium;

[0057] (2) Extract the sulfate-reducing bacteria, extinguish the fire, and then put them into the culture medium in step (1) for culture. Adjust the temperature of the culture medium to 30°C.

[0058] (3) Mix sulfate and cultured sulfate-reducing bacteria and let stand; wherein the mass ratio of sulfate to cultured sulfate-reducing bacteria is 1:1-10; the mass ratio used in this embodiment is 1:10;

[0059] (4) Inject the material from step (3) into the formation fractures through the filling pipe;

[0060] (5) Excessive sulfur ions combine with hydrogen ions to form hydrogen sulfide. The generated hydrogen sulfide will have a counteracting effect on sulfate-reducing bacteria, inhibiting the activity of sulfate-reducing bacteria until the sulfate-reducing bacteria are inactivated.

[0061] After 7 weeks, the sulfate conversion rate reached 15 kg / m3 / d, and the average sulfate removal rate was 88%.

[0062] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for preventing leakage during carbon dioxide geological storage, characterized in that: Includes the following steps: Step S1: Prepare a culture medium for sulfate-reducing bacteria; Step S2: Extract sulfate-reducing bacteria and culture them in a sulfate-reducing bacteria culture medium at 28~38℃ to obtain well-cultured sulfate-reducing bacteria; Step S3: For strata with a sulfate mineral content of not less than 5 wt.%, explore the strata, select strata with a high sulfate mineral content, inject the cultured sulfate-reducing bacteria into the fissures of the strata through a filling pipe, and let it stand. For caprock regions with sulfate mineral content less than 5 wt.%, sulfate and cultured sulfate-reducing bacteria are mixed, allowed to stand to obtain a mixture, and then the mixture is injected into the cracks of the caprock and allowed to stand; wherein, the mass ratio of sulfate to cultured sulfate-reducing bacteria is 1:1-10; Sulfate-reducing bacteria react with sulfate to produce a cementing substance that seals cracks, thereby preventing carbon dioxide leakage.

2. The method for preventing leakage during carbon dioxide geological storage according to claim 1, characterized in that: In step S2, the temperature of the sulfate-reducing bacteria culture medium is 30-35℃.

3. The method for preventing leakage during carbon dioxide geological storage according to claim 1, characterized in that: The strata with a sulfate mineral content of not less than 5 wt.% include gypsum layers or hard brittle rock layers.

4. The method for preventing leakage during the geological storage of carbon dioxide according to any one of claims 1 to 3, characterized in that: The pH value of the sulfate-reducing bacteria culture medium is 6.48-7.

43.

5. The method for preventing leakage during carbon dioxide geological storage according to claim 4, characterized in that: The sulfate-reducing bacteria culture medium was prepared using the following steps: Dissolve potassium dihydrogen phosphate, ammonium chloride, magnesium chloride hexahydrate, sodium sulfate, calcium chloride, sodium D-lactic acid solution, yeast extract, ferrous sulfate heptahydrate, and sodium thioglycolate in water to achieve the following concentrations: potassium dihydrogen phosphate 0.1-1 g / L, ammonium chloride 0.4-1.5 g / L, magnesium chloride hexahydrate 1.0-3.0 g / L, sodium sulfate 0.5-2.0 g / L, calcium chloride 0.01-0.1 g / L, sodium D-lactic acid solution 0.5-1.5 g / L, yeast extract 0.5-1.5 g / L, ferrous sulfate heptahydrate 0.1-1.0 g / L, and sodium thioglycolate 0.05-0.2 g / L. Adjust the pH to 6.8-7.4, pour the solution into an anaerobic culture flask, add ascorbic acid, seal the flask, and sterilize at high temperature.

6. The method for preventing leakage during carbon dioxide geological storage according to claim 4, characterized in that: The sulfate-reducing bacteria culture medium is prepared by the following steps: glucose, KH2PO4, K2HPO4, MgCl2•6H2O, FeCl2•12H2O, NH4Cl, and NaHS are dissolved in water to achieve the following concentrations: glucose 40-60 g / L, KH2PO4 0.5-1.5 g / L, K2HPO4 0.5-1.5 g / L, MgCl2•6H2O 0.5-1.5 g / L, FeCl2•12H2O 0.005-0.02 g / L, NH4Cl 0.2-1.0 g / L, and NaHS 4-6 g / L. The pH is adjusted to 6.8-7.2, and then the medium is sterilized at high temperature.

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