A method for electrocatalytic reduction of carbon dioxide for geological storage driven by vibration

Abstract

The present invention provides a method for vibration-driven electrocatalytic reduction of carbon dioxide for geological storage. Compared with the prior art, in the present invention, quartz crystals in a sandstone reservoir are first made to have piezoelectric effect by direct current polarization, and then the catalytic activity of a CO₂ electroreduction catalyst is activated by discharging the quartz crystals in the reservoir through vibration, which can catalyze the generation of organic small molecules such as formic acid and methanol from CO₂, realizing the permanent and stable storage of CO₂; meanwhile, SnCl₂ can consume O₂ generated by the oxygen evolution reaction in the anodic part of the CO₂ electroreduction reaction to generate SnO₂, which can be used as a catalyst to further promote the CO₂ reduction reaction, improve the storage amount and storage efficiency of CO₂, and also supply H⁺ for the cathodic CO₂ reduction reaction to further accelerate the CO₂ reduction reaction.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon dioxide geological storage, and particularly relates to a method for vibration-driven electrocatalytic reduction and geological storage of carbon dioxide. Background Technique

[0002] Due to its huge storage capacity and low storage cost, CO2 geological storage has become the most feasible CO2 storage technology at present. However, the common CO2 geological storage technologies mainly inject CO2 into deep saline aquifers under high pressure, and realize CO2 storage through structural trapping, hydrodynamic trapping, and geochemical trapping (dissolution and mineralization trapping). Many problems have been found in the implementation process of CO2 geological storage technology, including: (1) Poor stability of CO2 storage and easy leakage. Under high pressure, gaseous or supercritical CO2 is extremely easy to escape along high-permeability zones and fractures in geological bodies, resulting in the injected CO2 returning to the environment again, and it is difficult to control once leakage occurs; (2) Prone to trigger secondary geological disasters. The injection of high-pressure gaseous and supercritical CO2 destroys the stable pressure system of the formation, causing the closure and opening of cracks at all levels in a short time, and then triggering geological disasters such as earthquakes and landslides. In summary, it is of great practical significance to optimize the existing CO2 geological storage technology so that it can give full play to the role of CO2 storage.

[0003] Chinese Patent with Application No. ZL202210478169.2 discloses a method for in-situ deep geological supercritical storage of flue gas. Wells are drilled in the area within 10 km of the surface of the flue gas discharge port; after the flue gas is pressurized, it is injected into the storage layer deep in the ground along the well and then sealed; the depth of the storage layer from the surface is > 2000 meters; the storage layer is a key rock formation deep in the ground; the present invention enables the flue gas to be stably stored in-situ in a supercritical state more than 2000 meters deep underground, achieving the purpose of long-term, safe, and effective storage; this method adopts the "in-situ deep geological" injection method of flue gas near the power plant, and does not require the "capture-purification-transport" process and related technical equipment investment for CO2, simplifies the injection link, and greatly saves the operation cost.

[0004] The Chinese patent with the application number 202110743896.2 discloses a CO2 geological sequestration method and its system, including the following steps: determining a CO2 reservoir and a caprock according to the geological environment; excavating a CO2 injection well and a brine production well, both the CO2 injection well and the brine production well being connected to the CO2 reservoir; injecting CO2 into the CO2 reservoir through the CO2 injection well, and at the same time, extracting the brine in the CO2 reservoir through the brine production well to reduce the pressure of the CO2 reservoir and increase the available pore space of the CO2 reservoir; storing CO2 in the CO2 reservoir; in the present invention, a brine production well is excavated simultaneously with the excavation of the CO2 injection well, CO2 is injected into the CO2 reservoir through the CO2 injection well, and at the same time, the brine in the CO2 reservoir is extracted through the brine production well to reduce the pressure of the CO2 reservoir and increase the available pore space of the CO2 reservoir, so as to significantly increase the sequestration coefficient of the CO2 reservoir, and further increase the total amount of CO2 sequestered in the CO2 reservoir, that is, improve the sequestration capacity of the CO2 reservoir.

[0005] The Chinese patent with the application number 201480022096.X discloses a method for storing CO2 in a geological formation, the method including: (1) injecting a first composition containing CO2 into the formation; and (2) injecting a second composition containing CO2 and at least one polymer soluble in CO2 into the formation, wherein steps (1) and (2) are carried out separately in any order, and wherein the first and second compositions are different.

[0006] The Chinese patent with the application number 201910118992.0 discloses a method for storing CO2 in the gob area of a coal mine waste mine, specifically, the CO2 gas obtained by separation and enrichment from a fixed emission source is compressed to a supercritical state and then injected into the gob area of the coal mine waste mine, and the gob area and the underground abandoned roadway and chamber space are used for permanent storage. The CO2 storage status is monitored by arranging piezometric wells, and the safety of CO2 storage is ensured by controlling rock movement, leaving and reinforcing isolation coal pillars, setting up isolation walls, and grouting to block gaps; the present invention has a simple storage mechanism, low CO2 injection resistance, low injection cost, less geological exploration work volume, easy management, is conducive to the future reuse of CO2, the early high-pressure injection can relieve surface subsidence, and the existing engineering such as boreholes and shafts in the mine field can be reused, reducing the work volume. The large-scale thermal power plants and other CO2 centralized emission sources are associated with coal mine shafts, which is conducive to the in-situ storage of CO2.

[0007] The Chinese patent with the application number 201110126602.8 discloses a CO₂ geological storage system with excellent reliability for CO₂ geological storage and management. The CO₂ geological storage system of the present invention includes: a CO₂ geological storage unit that stores the CO₂ stored in multiple storage tanks into a designated horizon; a CO₂ concentration detection unit that is arranged in the unsaturated zone under the ground surface corresponding to the formation storing CO₂ and detects the CO₂ concentration in the unsaturated zone. The CO₂ geological storage unit includes: a multi-manifold unit that is formed by multiple partial branches to introduce the CO₂ for geological storage from multiple storage tanks; a distribution chamber unit whose inlet side is communicated with the multi-manifold unit and whose outlet side is connected to the injection pipe facing the above-mentioned formation, and supplies the CO₂ introduced through the multi-manifold unit to the above-mentioned injection pipe; a temperature adjustment unit that adjusts the temperature of the CO₂ introduced into the interior of the distribution chamber unit; a flow rate and flow pressure adjustment unit that adjusts the flow rate and flow pressure of the CO₂ to be injected underground through the distribution chamber unit.

[0008] In the above method, CO₂ is directly injected into various formations under high pressure, and the following problems mainly exist: (1) The engineering difficulty is large. Geological bodies all have relatively high formation pressures, and the current CO₂ geological storage technology can only inject CO₂ into the geological body by continuously increasing the injection pressure; (2) CO₂ is prone to leakage. The inherent heterogeneity and anisotropy of the formation cause the high-pressure gaseous or supercritical state CO₂ to easily gas channel along preferential seepage channels such as fractures and high-permeability zones, greatly reducing the CO₂ storage efficiency. Moreover, once leakage occurs, it is difficult to control; (3) Secondary geological disasters are triggered. The injection of high-pressure gaseous and supercritical CO₂ destroys the stable pressure system of the formation, causing the closure and opening of fractures at all levels in a short time, and then triggering geological disasters such as earthquakes and landslides.

[0009] To effectively inhibit CO₂ gas channeling, researchers have developed a series of CO₂ channeling sealants, which can inhibit CO₂ gas channeling to a certain extent.

[0010] The Chinese patent with the application number 202111388475.9 discloses a chemical grouting liquid for repairing deep formation CO₂ leakage and its preparation method, belonging to the field of carbon dioxide capture and emission reduction. The fault and fracture of the deep CO₂ geological storage reservoir are repaired and the CO₂ leakage problem is solved by the acid-resistant carbonate mineral particles formed by the chemical reaction of the grouting liquid and the leaked CO₂. The reactive grouting liquid provided by this patent is green, environmentally friendly, economical, and easy to operate. It can overcome the precipitation kinetics limitation of acid-resistant magnesite particles and catalyze the rapid precipitation of acid-resistant magnesite particles in the CO₂ leakage area of the deep formation; and it has the characteristics of low viscosity and wide penetration range, enabling it to enter small pores and fractures and become a more promising reactive grouting liquid, which can provide an effective chemical solution for the leakage repair and fault healing of deep CO₂ geological storage reservoirs and is suitable for popularization and application.

[0011] Chinese Patent No. 202110396172.5 discloses a method for biological prevention of CO2 escape in deep formation storage, belonging to the field of carbon dioxide emission reduction, which can solve the problems of easy leakage and escape of carbon dioxide, and includes the following steps: collecting geological data of the CO2 storage point to clarify the CO2 leakage path; arranging injection wells and production wells in the formation above the storage point; detecting whether the total amount of hydrogen sources in the formation meets the requirements of CO2 biological conversion; injecting biological liquid and hydrogen-rich organic matter into the selected formation through the injection wells; real-time monitoring the methane and CO2 content in the selected formation, and regularly detecting the microbial community composition; evaluating the leakage and biological conversion degree of the stored CO2, and adjusting the microbial community structure; extracting the generated CH4 through the production wells. The present invention utilizes the ability of microorganisms to convert CO2, converts the leaked CO2 into CH4 or organic matter above the storage layer, thereby preventing the escape of CO2, and at the same time can also recycle the leaked CO2, which has environmental protection and energy significance.

[0012] Chinese Patent No. 201310297000.8 discloses a CO2 gas drive plugging agent for high-temperature and low-permeability oil reservoirs, belonging to the application technology field of petroleum drilling engineering chemical agents. Its composition is: acrylamide, modifier, emulsifier, initiator, N,N-methylenebisacrylamide, formaldehyde, retarder and water; the weight percentages of each component are: acrylamide: 4.5-7.5%; modifier: 0.2-0.5%; emulsifier: 0.05-0.1%; initiator: 0.02-0.05%; N,N-methylenebisacrylamide: 0.3-1%; formaldehyde: 0.1-0.5%; retarder: 0.5-4.5%; water: the balance. The plugging agent provided by this patent has a low viscosity under the condition of not forming gel at normal temperature, is easy to be pumped into the formation, has high strength after gelling, has the characteristics of acid resistance, high temperature resistance, erosion resistance, stable performance, controllable gelation time and high plugging rate.

[0013] However, the above CO2 plugging agent also has the following problems: (1) Compared with other CO2 storage technologies, the advantage of CO2 geological storage technology lies in its large storage capacity, low cost, economy and high efficiency. The injection of various complex plugging agents, although improving the CO2 storage effect to a certain extent, the cost increase brought by the plugging agent itself and the cost increase brought by the increase in the engineering implementation difficulty greatly reduce the application value of CO2 geological storage technology; (2) Trigger secondary geological disasters. The injection of high-pressure gaseous and supercritical CO2 destroys the stable pressure system of the formation, causing the closure and opening of cracks at all levels in a short time, and then triggering geological disasters such as earthquakes and landslides. Summary of the Invention

[0014] In view of this, the technical problem to be solved by the present invention is to provide a method for geological storage of vibration-driven electrocatalytic reduction of carbon dioxide, which can improve the CO2 storage capacity and storage efficiency.

[0015] The present invention provides a method for geologically sequestering electrocatalytic reduction of carbon dioxide by vibration drive, comprising:

[0016] S1) Using a sandstone formation rich in quartz as the storage formation, drilling injection wells and production wells to the storage formation and perforating them;

[0017] S2) Connecting the injection well to the positive pole of the power supply, connecting the production well to the negative pole of the power supply, applying voltage for a period of time and then disconnecting;

[0018] S3) Pumping out the formation water in the storage formation through the production well, mixing it with the CO2 electroreduction catalyst, and reinjecting it into the storage formation through the injection well;

[0019] S4) Placing a vibration emitter in the injection well and lowering it to the storage formation, turning on the vibration emitter to emit vibration waves; placing a vibration signal collector in the production well;

[0020] S5) Pumping out the formation water through the production well, then mixing it with CO2 and SnCl2, and continuously injecting the resulting mixed solution into the storage formation through the injection well;

[0021] S6) When the vibration signal intensity decreases to the critical threshold and the formation pressure rises rapidly, stop the vibration and the injection of the mixed solution, reconnect the circuit and apply voltage between the injection well and the production well, and the positive and negative polarities are opposite to the previous time.

[0022] Preferably, in step S2), the electric field strength of the applied voltage is 1800 - 2200 V / 100 m; the time for applying the voltage is 10 - 30 h.

[0023] Preferably, the CO2 electroreduction catalyst in step S3) is selected from one or more of Sn, Pb, In, Bi, Ti, oxides of the above metals and alloy catalysts of the above metals; the mass ratio of the formation water to the CO2 electroreduction catalyst is (50 - 150):0.1.

[0024] Preferably, the CO2 electroreduction catalyst in step S3) is selected from SnO2; the mass ratio of the formation water to the CO2 electroreduction catalyst is 100:0.1.

[0025] Preferably, in step S4), the power of the vibration emitter for emitting vibration waves is 400 - 800 W.

[0026] Preferably, in step S5), under the formation pressure condition, the mass ratio of the formation water, CO2 and SnCl2 is (50 - 150):(10 - 20):0.025.

[0027] Preferably, in step S4), the mass ratio of formation water, CO2 and SnCl2 under formation pressure conditions is 100:15:0.025.

[0028] Preferably, the production rate of formation water in steps S3) and S5) is independently 100 - 200 cubic meters per day; the injection rate of the mixed solution into the storage formation in S4) is 100 - 150 cubic meters per day.

[0029] Preferably, the electric field strength of the applied voltage in step S5) is 1800 - 2200 V / 100m; the application time of the applied voltage is 10 - 30 h.

[0030] The present invention provides a method for geological storage of vibration-driven electrocatalytic reduction of carbon dioxide, including: S1) using a sandstone formation rich in quartz as the storage formation, drilling injection wells and production wells to the storage formation and perforating; S2) connecting the injection well to the positive pole of the power supply, connecting the production well to the negative pole of the power supply, applying voltage for a period of time and then disconnecting; S3) extracting the formation water from the storage formation through the production well and mixing it with the CO2 electroreduction catalyst, and reinjecting it into the storage formation through the injection well; S4) placing the vibration emitter in the injection well and lowering it to the storage formation, turning on the vibration emitter to emit vibration waves; placing the vibration signal collector in the production well; S5) extracting the formation water through the production well, then mixing it with CO2 and SnCl2 to obtain a mixed solution, and continuously injecting the obtained mixed solution into the storage formation through the injection well; S6) when the vibration signal intensity decreases to the critical threshold and the formation pressure rises rapidly, stop the vibration and the injection of the mixed solution, reconnect the circuit and apply voltage between the injection well and the production well, and the positive and negative polarities are opposite to the previous time. Compared with the prior art, the present invention first makes the quartz crystals in the sandstone reservoir have piezoelectric effect through direct current polarization, and then activates the catalytic activity of the CO2 electroreduction catalyst by activating the discharge of quartz crystals in the reservoir through vibration, which can catalyze CO2 to generate organic small molecules such as formic acid and methanol, realizing the permanent and stable storage of CO2; at the same time, SnCl2 can consume the O2 generated by the oxygen evolution reaction at the anode part of the CO2 electroreduction reaction to generate SnO2, which can be used as a catalyst to further promote the CO2 reduction reaction, improve the CO2 storage amount and storage efficiency, and also supply H + to further accelerate the CO2 reduction reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of directly polarizing quartz crystals in a sandstone reservoir in the present invention;

[0032] Figure 2 It is a schematic diagram of the distribution of the CO2 electroreduction catalyst injected into the formation in the present invention;

[0033] Figure 3Schematic diagram of voltage-activated CO2 electrocatalytic conversion in the present invention;

[0034] Figure 4 Variation curve of formation pressure during CO2 sequestration in Example 1 and Comparative Example 1 of the present invention. Detailed implementation manners

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0036] The present invention provides a method for vibration-driven electrocatalytic reduction and geological sequestration of carbon dioxide, including: S1) Using a sandstone formation rich in quartz as the sequestration formation, drilling injection wells and production wells to the sequestration formation and perforating; S2) Connecting the injection well to the positive electrode of the power supply, connecting the production well to the negative electrode of the power supply, applying voltage for a period of time and then disconnecting; S3) Pumping out the formation water in the sequestration formation through the production well, mixing it with a CO2 electroreduction catalyst, and reinjecting it into the sequestration formation through the injection well; S4) Placing a vibration transmitter in the injection well and lowering it to the sequestration formation, turning on the vibration transmitter to emit vibration waves; placing a vibration signal collector in the production well; S5) Pumping out the formation water through the production well, then mixing it with CO2 and SnCl2, and continuously injecting the obtained mixed solution into the sequestration formation through the injection well; S6) When the vibration signal intensity decreases to the critical threshold and the formation pressure rises rapidly, stop the vibration and the injection of the mixed solution, reconnect the circuit and apply voltage between the injection well and the production well, and the positive and negative electrode directions are opposite to the previous time.

[0037] Among them, the present invention does not have special restrictions on the sources of all raw materials, and they can be commercially available.

[0038] The present invention uses a sandstone formation rich in quartz as the sequestration formation, drilling injection wells and production wells to the target sequestration formation and perforating; the injection well and the production well are preferably two vertical wells.

[0039] Then apply voltage between the injection well and the production well and then disconnect; in the present invention, it is preferably to connect the injection well to the positive electrode of the power supply and the production well to the negative electrode of the power supply; the voltage is preferably a direct current voltage; the electric field strength is preferably 1800 - 2200 V / 100 m, more preferably 2000 V / 100 m; in the present invention, it is preferred to apply voltage to make the electric field strength in the sequestration formation 1800 - 2200 V / 100 m, more preferably 2000 V / 100 m; the time for applying voltage is preferably 10 - 30 h, more preferably 12 - 24 h; the purpose of this step is to use direct current to polarize quartz crystals in the sandstone reservoir, such asFigure 1 As shown. Natural quartz crystals mostly exhibit isotropic characteristics and have a weak piezoelectric effect. After being subjected to an electric field, the symmetry of the quartz crystal structure is broken, forming a polarization axis different from other crystal axes. The centers of positive and negative charges do not coincide, the polarization effect is significantly enhanced, and the piezoelectric effect becomes more obvious. After removing the external electric field, the quartz crystal can still maintain a certain residual polarization and still has a strong piezoelectric effect.

[0040] After the formation water in the storage formation is produced through the production well, it is mixed with the CO2 electroreduction catalyst; the production rate of the formation water is preferably 50 - 150 cubic meters per day, more preferably 80 - 120 cubic meters per day, and still more preferably 100 cubic meters per day; the CO2 electroreduction catalyst is preferably nanoparticles; the type of the CO2 electroreduction catalyst is preferably one or more of Sn, Pb, In, Bi, Ti, oxides of the above metals, and alloy catalysts of the above metals, more preferably SnO2; the mass ratio of the formation water to the CO2 electroreduction catalyst is preferably (50 - 150):0.1, more preferably (80 - 120):0.1, still more preferably (90 - 110):0.1, and most preferably 100:0.1; the obtained mixed liquid is continuously reinjected into the storage formation through the injection well; the injection rate is preferably 50 - 150 cubic meters per day, more preferably 100 - 130 cubic meters per day; see Figure 2 , Figure 2 is a schematic diagram of the distribution of the injected CO2 electroreduction catalyst in the formation.

[0041] Place the vibration emitter in the injection well and lower it to the storage formation, and turn on the vibration emitter to emit vibration waves at a certain frequency; place the vibration signal collector in the production well; in the present invention, it is preferably to place the vibration emitter in the injection well and lower it to the storage formation, emit vibration waves to the storage formation through the vibration emitter, and place the vibration signal collector in the storage formation of the production well for collecting vibration signals; the power of the vibration waves emitted by the vibration emitter is preferably 400 - 800 W, more preferably 500 - 700 W, and still more preferably 600 W. The purpose of this step is to vibrationally activate the piezoelectric material - quartz power generation in the sandstone reservoir. Bound charges appear at both ends of the polarized quartz perpendicular to the polarization direction, and the bound charges attract free charges in the environment, making the quartz crystal electrically neutral. Applying an external pressure parallel or perpendicular to the polarization direction to the polarized quartz crystal causes the quartz crystal to deform, the spacing of the bound charge layers in the crystal becomes smaller, and the free charges on the crystal surface become excessive and discharge.

[0042] Producing formation water through a production well, then mixing it with CO2 and SnCl2, and injecting the resulting mixed solution into a storage formation through an injection well; the rate of producing formation water is preferably 100 - 200 cubic meters per day, more preferably 120 - 140 cubic meters per day, still more preferably 130 cubic meters per day; under formation pressure conditions, the mass ratio of the formation water, CO2, and SnCl2 is preferably (50 - 150):(10 - 20):0.025, more preferably (80 - 120):(13 - 17):0.025, still more preferably (90 - 110):(14 - 16):0.025, and most preferably 100:15:0.025; the mixed solution is injected into the storage formation through the injection well, and the injection rate into the storage formation is preferably 100 - 200 cubic meters per day, more preferably 120 - 140 cubic meters per day, still more preferably 130 cubic meters per day; this step realizes circulation by adding CO2 and SnCl2 to the produced fluid and reinjecting it. Under the condition of pre-injecting a CO2 electroreduction catalyst such as SnO2 and then injecting CO2 + H2O + SnCl2, long-term and stable conversion of CO2 can be achieved.

[0043] During this process, ultrasonic stimulation of the quartz crystal generates electricity, causing CO2 electroreduction. See Figure 3 , Figure 3 is a schematic diagram of activating CO2 electrocatalytic conversion by quartz crystal power generation; during the reduction process, the CO2 electroreduction catalyst can catalyze CO2 to generate formic acid, methanol, etc. Under the action of vibration, the quartz discharges to activate the catalytic activity of the CO2 electroreduction catalyst, catalyzing CO2 to generate organic small molecules such as formic acid and methanol, realizing the permanent and stable storage of CO2. The reaction equations are as follows:

[0044] Cathode reaction: CO2 + 2H + + 2e - = HCOOH

[0045] Anode reaction: H2O - 4e - = 4H + + O2

[0046] Meanwhile, this step can also realize that SnCl2 consumes the by-product O2 of the CO2 reduction reaction and generates SnO2 to continue catalyzing the CO2 reduction. In the CO2 electrocatalytic reduction reaction, an oxygen evolution reaction occurs at the anode part. Injecting SnCl2 reacts with the evolved O2, consumes O2, and generates SnO2. SnO2, as a catalyst, further promotes the CO2 reduction reaction, increasing the CO2 storage amount and storage efficiency. At the same time, it supplies H + for the cathode CO2 reduction reaction, further accelerating the CO2 reduction reaction. The reaction equations are as follows:

[0047] SnCl2 + 1 / 2O2 + H2O = SnO2 + 2HCl

[0048] When the vibration signal strength decreases to the critical threshold and the formation pressure rises rapidly, stop the vibration and the injection of the mixed solution, reconnect the circuit to apply a voltage between the injection well and the production well, and the positive and negative polarities are opposite to the previous time; in the present invention, it is preferred to apply a voltage so that the electric field strength in the sealed formation is 1800-2200 V / 100 m, more preferably 2000 V / 100 m; the time for applying the voltage is preferably 10-30 h, more preferably 12-24 h. As time goes by, the polarization effect of quartz gradually weakens and the ability of vibration to generate charges gradually weakens, resulting in a significant reduction in the rate of CO2 electroreduction; reconnect the circuit to polarize quartz again, so as to ensure that quartz can always generate high-density charges under vibration conditions and ensure the efficiency of CO2 electroreduction.

[0049] In the present invention, first, the quartz rich in the sandstone reservoir is polarized by a DC electrode to endow it with piezoelectric effect, and then the quartz crystal is activated by vibration to generate electricity. Under the vibration effect, the reservoir discharges to activate the catalytic activity of the CO2 electroreduction catalyst, which can catalyze CO2 to generate organic small molecules such as formic acid and methanol, realizing the permanent and stable storage of CO2; at the same time, SnCl2 can consume the O2 generated by the oxygen evolution reaction in the anode part to generate SnO2, which can be used as a catalyst to further promote the CO2 reduction reaction, improve the CO2 storage capacity and storage efficiency, and also supply H for the cathode CO2 reduction reaction + , further accelerating the CO2 reduction reaction.

[0050] In order to further illustrate the present invention, the following is a detailed description of a method for vibration-driven electrocatalytic reduction and geological storage of carbon dioxide provided by the present invention in combination with embodiments.

[0051] The reagents used in the following examples are all commercially available.

[0052] Example 1

[0053] (1) Select a sandstone formation rich in quartz as the target horizon, and the formation pressure of the target horizon is about 9.5 MPa and the formation temperature is 40 °C;

[0054] (2) Drill two vertical wells as the injection well and the production well to the target horizon and perforate them;

[0055] (3) Connect the injection well to the positive pole of the power supply and the production well to the negative pole of the power supply, and apply a 2000 V / 100 m DC electric field between the two wells. Disconnect the circuit after 1 day of connection;

[0056] (4) Mix the formation water produced at a rate of 100 cubic meters per day through the production well with nano-SnO2 particles etc. (CO2 electroreduction catalyst) in a mass ratio of 100:0.1 evenly, and reinject it into the target formation through the injection well at a rate of 100 cubic meters per day.

[0057] (4) Place the vibration emitter in the injection well and lower it to the target horizon. Turn on the vibration emitter to emit vibration waves to the target formation at a power of 600 W. Install a vibration signal collector at the target horizon in the production wellbore.

[0058] (5) Mix the formation water produced at a rate of 100 cubic meters per day with CO2 and SnCl2 at a mass ratio of (100:15:0.025) (under formation pressure conditions) evenly and slowly inject it into the deep formation through the injection well at a rate of 130 cubic meters per day. At this stage, the formation pressure is about 14.0 MPa and remains stable for a long time.

[0059] (6) When the signal intensity of the vibration signal collector continuously decreases to the critical threshold (25% of the initial signal intensity) and the formation pressure rises rapidly again. Reconnect the DC circuit and apply a 2000 V / 100 m DC electric field between the two wells for 1 day; then, continue the CO2 sequestration work.

[0060] Comparative Example 1

[0061] (1) Select a sandstone formation rich in quartz as the target horizon, with the formation pressure of the target horizon about 9.5 MPa and the formation temperature 40 °C;

[0062] (2) Drill two vertical wells as the injection well and the production well to the target horizon and perforate them;

[0063] (3) Mix the formation water produced at a rate of 100 cubic meters per day and CO2 at a mass ratio of (100:15) (under formation pressure conditions) evenly and slowly inject it into the deep formation through the injection well at a rate of 130 cubic meters per day. Due to injection-production imbalance, the formation pressure continuously rises, from 11.5 MPa in the initial stage to about 13.7 MPa and finally to about 16.6 MPa, and then shut in the well.

[0064] See Figure 4 , Figure 4 is the change curve of the formation pressure during the CO2 sequestration process in Example 1 of the present invention and Comparative Example 1. It can be seen from Figure 4 that in Comparative Example 1, the formation pressure rises rapidly during the conventional CO2 injection stage, indicating that the conventional CO2 sequestration capacity is limited, the sequestration stability is poor, the sequestration efficiency is low, and the sequestration safety is poor; after using the new technology in Example 1, the formation pressure drops rapidly and is accompanied by long-term stability, indicating that the injected CO2 has been transformed and does not exist in a gaseous state, and finally can greatly increase the CO2 sequestration capacity, significantly improve the CO2 sequestration stability, and significantly enhance the sequestration safety.

Claims

1. A method for electrocatalytic reduction of carbon dioxide for geological storage driven by vibration, characterized in that It includes the following steps: S1) Using a sandstone formation rich in quartz as the storage formation, drilling injection wells and production wells to the storage formation and perforating them; S2) Connecting the injection well to the positive pole of the power supply, connecting the production well to the negative pole of the power supply, applying voltage for a period of time and then disconnecting; S3) After extracting the formation water from the storage formation through the production well and mixing it with the CO2 electroreduction catalyst, reinjecting it into the storage formation through the injection well; S4) Placing the vibration emitter in the injection well and lowering it to the storage formation, turning on the vibration emitter to emit vibration waves; placing the vibration signal collector in the production well; S5) Extracting the formation water through the production well, and then mixing it with CO2 and SnCl2, and continuously injecting the obtained mixed solution into the storage formation through the injection well; S6) When the vibration signal intensity decreases to the critical threshold and the formation pressure rises rapidly, stop the vibration and the injection of the mixed solution, reconnect the circuit and apply voltage between the injection well and the production well, and the positive and negative polarities are opposite to the previous time.

2. The method according to claim 1, wherein In step S2), the electric field intensity of the applied voltage is 1800 - 2200 V / 100 m; the time for applying the voltage is 10 - 30 h.

3. The method according to claim 1, characterized in that, The CO2 electroreduction catalyst in step S3) is selected from one or more of Sn, Pb, In, Bi, Ti, oxides of the above metals, and alloy catalysts of the above metals; the mass ratio of the formation water to the CO2 electroreduction catalyst is (50 - 150):0.1; the above metals are Sn, Pb, In, Bi, or Ti.

4. The method according to claim 1, wherein The CO2 electroreduction catalyst in step S3) is selected from SnO2; the mass ratio of the formation water to the CO2 electroreduction catalyst is 100:0.

1.

5. The method according to claim 1, characterized in that In step S4), the power of the vibration waves emitted by the vibration emitter is 400 - 800 W.

6. The method according to claim 1, characterized in that, In step S5), under the formation pressure condition, the mass ratio of the formation water, CO2, and SnCl2 is (50 - 150):(10 - 20):0.

025.

7. The method according to claim 1, wherein In step S5), under the formation pressure condition, the mass ratio of the formation water, CO2, and SnCl2 is 100:15:0.

025.

8. The method according to claim 1, wherein In steps S3) and S5), the extraction rate of the formation water is independently 100 - 200 cubic meters per day; in S4), the injection rate of the mixed solution into the storage formation is 100 - 150 cubic meters per day.

9. The method according to claim 1, wherein In step S6), the electric field intensity of the applied voltage is 1800 - 2200 V / 100 m; the time for applying the voltage is 10 - 30 h.

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