A method for increasing the permeability and injection-production capacity of an aquifer compressed CO2 energy storage reservoir

Abstract

The application discloses a method for increasing the permeability and injection-production capacity of a water-bearing layer compressed CO2 energy storage reservoir, and belongs to the technical field of water-bearing layer energy storage and reservoir reconstruction. The method comprises the following steps: obtaining the mineral composition, formation water composition, porosity and permeability parameters of a target water-bearing layer, configuring an HCl and HF compound acid liquid system, injecting the system into the reservoir through a wellbore, closing the well and standing, forming a high-permeability area comprising an acidification permeability-increasing area and an acidification transition area in the near-well area, then injecting CO2 into the reservoir to build an initial gas pocket, carrying out CO2 cyclic injection-production energy storage operation, calculating the injection-production capacity index through wellhead temperature and pressure monitoring and injection-production rate, and evaluating the permeability-increasing effect. The method can significantly increase the permeability of the near-well reservoir, reduce the CO2 injection-production flow resistance, simultaneously increase the system injection and extraction capacity, stabilize the cyclic operation parameter fluctuation, and improve the system energy storage scale and operation stability.

Description

Technical Field

[0001] This invention relates to the field of aquifer energy storage and reservoir modification technology, and in particular to a method for enhancing the permeability and injection-production capacity of aquifer compressed CO2 energy storage reservoir. Background Technology

[0002] With the continuous advancement of the global "dual carbon" strategy, the installed capacity of renewable energy sources such as wind power and photovoltaics has grown rapidly. However, the intermittent and volatile characteristics of renewable energy are not matched with the grid's absorption capacity, resulting in prominent issues of wind and solar curtailment. Large-scale energy storage technology has become a core support solution for smoothing out fluctuations in renewable energy output and improving the grid's flexible adjustment capabilities.

[0003] Aquifer compressed CO2 energy storage is a novel underground energy storage technology suitable for long-term, large-capacity scenarios. It boasts advantages such as high energy storage efficiency, high energy density, and wide site selection range, and can be integrated with deep aquifer geological spaces to achieve large-scale energy storage. However, deep aquifer reservoirs generally exhibit characteristics such as tight mineral cementation and poor pore connectivity, resulting in low reservoir permeability near the wellbore. On the one hand, this leads to rapid accumulation of reservoir pressure during the initial CO2 gasbag filling stage, limiting injection capacity and prolonging the gasbag construction period. On the other hand, during cyclic injection and production operations, the high flow resistance in the near-wellbore area simultaneously restricts CO2 injection and extraction capabilities, exacerbating temperature and pressure fluctuations in the wellbore and reservoir, and reducing the stability and cyclic efficiency of the energy storage system.

[0004] Existing reservoir acidizing technologies have been widely applied in geothermal extraction and oil and gas reservoir production enhancement. Geothermal acidizing aims to expand inter-well reservoir connectivity, while oil and gas reservoir acidizing primarily aims to increase single-well oil and gas production. However, aquifer compressed CO2 energy storage systems possess unique cyclic injection and production characteristics. They not only need to ensure injection capacity during the CO2 injection phase but also simultaneously consider CO2 reflux capacity during the extraction phase, the initial gasbag construction efficiency, and the stability of wellhead temperature and pressure during multiple cycles. Traditional acidizing methods are designed for single-production or inter-well connectivity scenarios and cannot directly adapt to the cyclic injection and production requirements of aquifer compressed CO2 energy storage, making it difficult to simultaneously achieve a synergistic improvement in injection and extraction capabilities.

[0005] Therefore, developing a reservoir permeability enhancement method for aquifer compressed CO2 energy storage systems, which can specifically improve near-wellbore reservoir permeability and simultaneously optimize injection and extraction capabilities, is of great significance for promoting the engineering application of aquifer compressed CO2 energy storage technology. Summary of the Invention

[0006] The purpose of this invention is to provide a method for enhancing the permeability and injection-production capacity of aquifer compressed CO2 energy storage reservoir, in order to solve the above-mentioned problems.

[0007] This invention provides a method for enhancing the permeability and injection-production capacity of aquifer compressed CO2 energy storage reservoir, comprising the following steps: (1) Select the target aquifer reservoir suitable for compressed CO2 energy storage; (2) Obtain the mineral composition, formation water ion composition, reservoir thickness, porosity and permeability parameters of the target aquifer; (3) Configure an aquifer compressed CO2 energy storage ground circulation system, the ground circulation system being used to realize the entire process of CO2 compression, cooling, injection, extraction, heating and expansion power generation; (4) Based on the composition of carbonate and aluminosilicate minerals in the target aquifer, a composite acid system consisting of HCl and HF is prepared to dissolve both carbonate and aluminosilicate minerals simultaneously and obtain higher reservoir pore permeability.

[0008] (5) Inject the composite acid solution into the target aquifer through the wellbore, and monitor the dynamic changes in pressure at the wellhead and in the reservoir in real time during the injection process in order to evaluate the reservoir acidizing and permeability enhancement effect in real time; (6) After the acid injection is completed, the well is shut in and left to stand. The composite acid solution reacts fully with the reservoir minerals to form a high-permeability zone consisting of an acidizing permeation enhancement zone and an acidizing transition zone in the near-wellbore area around the wellbore, while restoring the formation pressure. This allows for subsequent CO2 injection and storage. At the same time, the acid solution is allowed to migrate and react further in the reservoir to obtain a larger transformation radius and higher permeability.

[0009] (7) Inject CO2 into the target aquifer after acid treatment to form an initial CO2 gasbag; so that CO2 can be efficiently extracted for expansion power generation during subsequent energy storage cycles.

[0010] (8) Perform CO2 energy storage cycle operation, wherein the cycle operation includes a gas injection energy storage stage and an extraction energy release stage; (9) Monitor wellhead temperature, wellhead pressure, CO2 injection rate, and CO2 extraction rate during the gasbag filling period and the circulating energy storage period, and calculate and evaluate the reservoir's injection and extraction capabilities. Monitor wellhead temperature and pressure during the gasbag filling period and the circulating energy storage injection and extraction period. Based on the monitoring results, calculate the unit pressure increment injection rate during the gasbag filling period, the unit pressure increment injection rate during the circulating energy storage period, and the extraction rate, and evaluate the reservoir acidizing and permeability enhancement effect.

[0011] Preferably, in the composite acid system, the mass concentration of HCl is 1% to 20%, and the mass concentration of HF is 1% to 5%.

[0012] Preferably, the injection time of the composite acid solution in step (5) is 1 to 10 days, and the injection rate is determined according to the thickness, permeability and mineral composition parameters of the target aquifer.

[0013] Preferably, the time for closing the well and letting it stand in step (6) is 1 to 10 days.

[0014] Preferably, the injection capacity in step (9) is characterized by an injection capacity index, which is the ratio of the CO2 injection rate to the wellhead pressure increment at the corresponding injection stage. The injection stage includes the gasbag filling injection stage and the circulating energy storage gas injection stage.

[0015] Preferably, the extraction capacity in step (9) is characterized by an extraction capacity index, which is the ratio of the CO2 extraction rate to the wellhead pressure increment at the corresponding extraction stage.

[0016] Preferably, the acidizing and permeation-enhancing zone is a near-wellbore strong dissolution reaction zone adjacent to the wellbore, and the acidizing transition zone is a weak dissolution reaction zone distributed around the acidizing and permeation-enhancing zone.

[0017] Preferably, the ground circulation system includes a CO2 working fluid circulation branch and a heat exchange medium circulation branch; The CO2 working fluid circulation branch is equipped with a first-stage compressor, a first-stage cooler, a second-stage compressor, a second-stage heat exchanger, a CO2 injection valve, a wellbore, a CO2 extraction valve, a first-stage heater, a first-stage expander, a second-stage heater, a second-stage expander, and a generator. Along the flow direction of CO2 injection into the reservoir, the first-stage compressor, first-stage cooler, second-stage compressor, second-stage heat exchanger, CO2 injection valve, and wellbore are connected in series. Along the flow direction of CO2 extraction from the well, the wellbore, CO2 extraction valve, first-stage heater, first-stage expander, second-stage heater, and second-stage expander are connected in series. Both the first-stage and second-stage expanders are connected to the generator for power transmission. The heat exchange medium circulation branch is equipped with a hot flow side mixer, a heat storage tank, a cold flow side converter, a cold storage tank, and heat exchange pipelines. The heat exchange medium circulation branch is connected to the first-stage cooler, the second-stage heat exchanger, the first-stage heater, and the second-stage heater for heat exchange, and is used to recover and store the compression heat of CO2, heat and extract CO2, and recover and store the expansion cold energy of CO2.

[0018] Preferably, the CO2 energy storage cycle in step (8) adopts a daily, weekly, or quarterly cycle operation mode: The daily cycle operation mode is as follows: During the off-peak period of electricity consumption, surplus electricity is used to drive the compressor to compress CO2, which is then cooled by the cooler and injected into the target aquifer to complete energy storage; During the peak period of electricity consumption, CO2 in the target aquifer is extracted to the ground, heated by the heater, and then sent to the expander to do work and drive the generator to generate electricity, thus completing energy release. The weekly cycle operation mode is as follows: CO2 is compressed and injected into energy storage on days or periods of low electricity consumption, and CO2 is extracted and released to generate electricity on days or periods of high electricity consumption. The seasonal cycle operation mode is as follows: CO2 is compressed and injected into energy storage during the off-peak season and CO2 is extracted and released to generate electricity during the peak season.

[0019] Preferably, the target aquifer is a sandstone reservoir containing carbonate or aluminosilicate minerals cemented / filled.

[0020] Therefore, the present invention employs the above-mentioned method for enhancing the permeability and injection-production capacity of aquifer compressed CO2 energy storage reservoir, which has the following beneficial effects: (1) The composite acid system composed of HCl and HF can simultaneously dissolve carbonate minerals and aluminosilicate minerals in the reservoir, forming a gradient seepage structure of acidification and permeation enhancement zone and acidification transition zone around the wellbore, which greatly improves the porosity and permeability of the near-well area and effectively reduces the near-well flow resistance during CO2 injection and extraction return process.

[0021] (2) After acidizing, the near-well reservoir injection resistance is reduced, which can significantly reduce the wellhead pressure accumulation during the gasbag filling period, improve the injection capacity index during the gasbag filling stage, accelerate the construction speed of the initial CO2 gasbag, expand the CO2 scale that can be sealed in a single well, and increase the overall capacity limit of the energy storage system.

[0022] (3) The high permeability zone near the well can suppress pressure and temperature fluctuations during the cyclic injection and production process, reduce the parameter fluctuation amplitude of the wellbore and reservoir under multi-cycle conditions, and ensure the reliability and safety of the long-term continuous operation of the energy storage system.

[0023] (4) Acidification modification can simultaneously improve the injection capacity index and extraction capacity index of the cycle energy storage stage. The improvement effect of extraction capacity is particularly significant, which can support larger-scale CO2 cycle injection and extraction and expansion power generation, effectively improving the energy release power and overall operating efficiency of the energy storage system.

[0024] (5) The concentration of composite acid, injection rate and injection duration can be matched and adjusted according to the mineral composition, thickness and permeability parameters of the target reservoir. The optimal construction parameters can be determined by quantitative comparison of the injection and production capacity improvement effect with acid consumption and construction cost, so as to avoid the cost waste caused by excessive acidification and take into account both the transformation effect and the engineering economy.

[0025] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the system structure of Embodiment 1 of the method for enhancing the permeability and injection-production capacity of aquifer compressed CO2 energy storage reservoir according to the present invention.

[0027] Reference numerals: 1. First-stage compressor; 2. First-stage cooler; 3. Second-stage compressor; 4. Second-stage heat exchanger; 5. CO2 injection valve; 6. Wellbore; 7. CO2 extraction valve; 8. First-stage heater; 9. First-stage expander; 10. Second-stage heater; 11. Second-stage expander; 12. Hot-flow side mixer; 13. Heat storage tank; 14. Cold-flow side converter; 15. Cold storage tank; 16. Overlying strata; 17. Caprock; 18. Target aquifer reservoir; 19. Underlying bedrock; 20. Acidizing and permeability enhancement zone; 21. Acidizing transition zone; 22. CO2 gasbag zone. Detailed Implementation

[0028] To better understand the above technical solutions, a detailed description of the solutions will be provided below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0030] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0031] Example 1 Reference Figure 1 The system structure shown in this embodiment implements the method for enhancing the permeability and injection-production capacity of aquifer compressed CO2 energy storage reservoir according to the following steps: Select the target aquifer reservoir: The calcareous cemented sandstone aquifer of the Honghuatao Formation in the Hengyang Basin was selected as the target aquifer reservoir 18, with a burial depth of 2100–2200 m. The upper part of the reservoir is a low-permeability mudstone caprock of the Daijiaping Formation 17, above which is an overlying stratum 16, and the lower part is a bedrock 19 underlying the low-permeability mudstone of the Honghuatao Formation. The permeability limitation of this type of reservoir mainly originates from carbonate and aluminosilicate cements, which can be permeable enhanced by dissolution with a composite acid solution, meeting the applicable reservoir conditions for this method.

[0032] Obtain reservoir physicochemical parameters: Borehole coring and groundwater sampling tests were conducted on the target aquifer reservoir 18 to obtain the following basic parameters: mineral composition: quartz, calcite, dolomite, albite, illite, and kaolinite; formation water: Ca-Mg-Na-HCO3 type; initial reservoir porosity: 0.2; initial permeability: 1.3 × 10⁻⁶. -13 m 2 .

[0033] Configure a ground circulation system: A ground-based CO2 energy storage system for aquifer compression was constructed. The ground-based circulation system includes a CO2 working fluid circulation branch and a heat exchange medium circulation branch, which realizes the entire process of CO2 compression, cooling, injection, extraction, heating and expansion for power generation.

[0034] The CO2 working fluid circulation branch includes a compressor, a cooler, a wellhead injection and production valve group, a heater, an expander, and a generator: along the CO2 injection flow direction, the compressor is divided into a first-stage compressor 1 and a second-stage compressor 3, and the cooler is divided into a first-stage cooler 2 and a second-stage heat exchanger 4, arranged in series; the wellhead injection and production valve group consists of a CO2 injection valve 5 and a CO2 extraction valve 7, respectively installed on the injection passage and extraction passage of the wellbore 6; along the CO2 extraction flow direction, the heater is divided into a first-stage heater 8 and a second-stage heater 10, and the expander is divided into a first-stage expander 9 and a second-stage expander 11, arranged in series; both expanders are driven by a generator to convert the expansion work into electrical energy output.

[0035] The heat exchange medium circulation branch includes a heat storage tank 13 and a cold storage tank 15, and is equipped with a hot flow side mixer 12, a cold flow side converter 14, and heat exchange pipelines: During the compression stage, the cooler and heat exchanger recover the heat of CO2 compression and transport it to the heat storage tank 13 for storage through the heat exchange medium; During the expansion stage, the heat storage tank 13 outputs heat to the heater to heat CO2 to enhance the expansion work capacity; The low-temperature CO2 cold energy after expansion work is recovered to the cold storage tank 15 through the heat exchange medium and used to assist in cooling CO2 during the compression stage, realizing energy cascade recovery and utilization.

[0036] Configure a composite acid solution system: Based on the proportion of carbonate and aluminosilicate minerals in the target reservoir, a composite acid system consisting of HCl and HF was prepared, with HCl having a mass concentration of 10% and HF a mass concentration of 1.5%. HCl is mainly used to dissolve carbonate cements such as calcite and dolomite, while HF is mainly used to dissolve aluminosilicate minerals such as albite, illite, and kaolinite. The combination of the two can dissolve both types of minerals simultaneously, resulting in better pore connectivity.

[0037] Injecting composite acid solution: The aforementioned composite acid solution was injected into the target aquifer reservoir 18 through wellbore 6 at an injection temperature of 55°C, an injection rate of 30 kg / s, and an injection duration of 5 days. During the injection process, high-frequency monitoring of the dynamic pressure changes at the wellhead and in the reservoir was conducted. This served two purposes: firstly, to control the bottomhole pressure to be lower than the fracturing pressure of the caprock 17, ensuring the integrity of the reservoir and caprock; and secondly, to assess the dissolution and permeability enhancement effect in real time by monitoring the rate of increase in wellhead pressure, indicating a continuous increase in near-wellbore permeability.

[0038] Well shut-in and static reaction: After acid injection, the CO2 injection valve 5 and CO2 extraction valve 7 are closed, and the well is shut in for 5 days. This shut-in period serves a dual purpose: first, it allows the remaining acid to slowly diffuse into the deeper reservoir, further reacting with the minerals and expanding the stimulation radius. Around the wellbore 6, an acidizing and permeability-enhancing zone 20 (a strong near-wellbore dissolution reaction zone) and an acidizing transition zone 21 (a weak dissolution reaction zone) are sequentially formed adjacent to the wellbore. This gradient permeability structure avoids gas channeling problems caused by sudden permeability changes, ensuring uniform bidirectional CO2 flow. Second, it gradually restores formation pressure, preventing excessive pressure differentials during subsequent CO2 injections that could cause rapid reservoir damage due to pressure deficits.

[0039] Formation of the initial CO2 airbag: Open the CO2 injection valve 5 and continuously inject CO2 into the acidified target aquifer reservoir 18 at a rate of 50 kg / s for 365 days to form a large-scale CO2 gas bladder area 22 inside the reservoir, which will serve as the working fluid storage capacity for subsequent circulating energy storage.

[0040] Perform CO2 energy storage cycle operation: The energy storage-release cycle is carried out using a daily cycle operation mode. The complete cycle includes four stages: gas injection, gas shutdown, gas extraction, and gas shutdown. During periods of low electricity demand (energy storage phase), surplus electricity is used to drive the first-stage compressor 1 and the second-stage compressor 3 to perform two-stage compression of CO2. The heat generated during the compression process is recovered by the first-stage cooler 2 and the second-stage heat exchanger 4 and stored in the heat storage tank 13. The cooled CO2 is then injected into the target aquifer reservoir 18 through the CO2 injection valve 5 and the wellbore 6 to complete energy storage. The single-cycle injection duration is 12 hours, and the injection rate is 50 kg / s. After the injection is completed, the injection is stopped to stabilize the reservoir pressure and temperature. During peak electricity consumption (energy release phase), CO2 extraction valve 7 is opened, and CO2 in the target aquifer reservoir 18 is extracted to the surface through wellbore 6. After being heated by the heat stored in heat storage tank 13 by the first-stage heater 8 and the second-stage heater 10, it is sent to the first-stage expander 9 and the second-stage expander 11 to do work and drive the generator to generate electricity. The low-temperature CO2 after doing work is recovered to the cold storage tank 15, completing the energy release. The extraction time of a single cycle is 4 hours, and the extraction rate is 150 kg / s. After the extraction is completed, the extraction stops to stabilize the reservoir pressure fluctuations and enter the next cycle.

[0041] Monitoring and injection-production capability evaluation: During the gasbag filling period and the circulating energy storage period, wellhead temperature, wellhead pressure, CO2 injection rate and CO2 extraction rate were continuously monitored, and the injection capacity index and extraction capacity index were calculated respectively. At the same time, the near-well permeability distribution and permeation radius parameters after acidizing were obtained through reservoir testing.

[0042] Among them, the injection capacity index is the ratio of CO2 injection rate to the wellhead pressure increment during the corresponding injection stage, and the extraction capacity index is the ratio of CO2 extraction rate to the wellhead pressure increment during the corresponding extraction stage; according to the operation stage, it can be divided into the gasbag filling period injection capacity index, the circulating energy storage period injection capacity index, and the circulating energy storage period extraction capacity index.

[0043] Comparative Example 1 This comparative example uses the exact same target aquifer reservoir, surface circulation system configuration, initial gasbag injection parameters, and circulation operation parameters as the example. The only difference is that the acidizing and permeation enhancement treatment, which involves compound acid preparation, acid injection, and well shut-in and static treatment, is not performed. Instead, the initial CO2 gasbag filling and circulation energy storage operation are carried out directly with the original reservoir.

[0044] The reservoir baseline parameters for this comparative example are: original permeability 1.3 × 10⁻⁶ -13 m 2 In areas without acidification modification, under the same injection and production rates, the wellhead pressure rises rapidly during the gasbag filling period, the reservoir injection resistance is high, and the initial gasbag construction efficiency is low; during the circulating energy storage stage, the wellhead pressure and temperature fluctuate greatly, the CO2 injection and extraction return resistance is high, and the extraction rate decays significantly in the later stage.

[0045] Through quantitative comparison, compared with this comparative example, in terms of reservoir stimulation, Example 1, through acid erosion to form a gradient seepage structure, achieved a maximum permeability enhancement radius of 6m, and increased the maximum permeability in the near-wellbore area to 1.55×10⁻⁶ m. -11 m 2 The permeability of the original reservoir was increased by 119 times compared to Comparative Example 1; In terms of operational performance, the injection capacity index during the gasbag filling period of the embodiment is 2.68 kg / (s·MPa) higher than that of Comparative Example 1, the injection capacity index during the circulating energy storage period is 9.6 kg / (s·MPa) higher than that of Comparative Example 1, and the extraction capacity index during the circulating energy storage period is 17.61 kg / (s·MPa) higher than that of Comparative Example 1. It can be seen that the acidizing and permeation enhancement method of the present invention has a significant effect on improving the reservoir permeability and circulating injection and production capacity.

[0046] Therefore, this invention employs the aforementioned method for enhancing the permeability and injection / production capacity of aquifer compressed CO2 energy storage reservoir. Through a composite acid system composed of HCl and HF, it simultaneously dissolves carbonate and aluminosilicate minerals in the reservoir, forming a gradient seepage structure around the wellbore between an acidizing and permeability enhancement zone and an acidizing transition zone. This significantly increases the porosity and permeability of the near-wellbore region, effectively reducing near-wellbore flow resistance during CO2 injection and extraction recirculation. After acidizing, the reduced near-wellbore reservoir injection resistance significantly decreases the wellhead pressure accumulation during the gasbag filling period, improves the injection capacity index during the gasbag filling stage, accelerates the initial CO2 gasbag construction speed, expands the CO2 capacity that can be stored in a single well, and increases the overall capacity ceiling of the energy storage system.

[0047] Near-well high-permeability zones can mitigate pressure and temperature fluctuations during the cyclic injection and production process, reducing parameter fluctuations in the wellbore and reservoir under multi-cycle conditions, and ensuring the reliability and safety of the energy storage system's long-term continuous operation. Acidizing can simultaneously improve the injection and extraction capacity indices during the cyclic energy storage phase, with the improvement in extraction capacity being particularly significant. This can support larger-scale CO2 cyclic injection and production and expansion power generation, effectively enhancing the energy release power and overall operating efficiency of the energy storage system.

[0048] Based on the mineral composition, thickness, and permeability parameters of the target reservoir, the concentration of composite acid, the injection rate, and the injection duration can be adjusted accordingly. By quantitatively comparing the injection and production capacity improvement effect with acid consumption and construction costs, the optimal construction parameters can be determined, avoiding cost waste caused by excessive acidizing and balancing the transformation effect with the economic efficiency of the project.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for enhancing the permeability and injection-production capacity of aquifer compressed CO2 energy storage reservoir, characterized in that, Includes the following steps: (1) Select the target aquifer reservoir suitable for compressed CO2 energy storage; (2) Obtain the mineral composition, formation water ion composition, reservoir thickness, porosity and permeability parameters of the target aquifer; (3) Configure an aquifer compressed CO2 energy storage ground circulation system, the ground circulation system being used to realize the entire process of CO2 compression, cooling, injection, extraction, heating and expansion power generation; (4) Based on the composition of carbonate and aluminosilicate minerals in the target aquifer, prepare a composite acid system consisting of HCl and HF. (5) Inject the composite acid solution into the target aquifer through the wellbore, and monitor the dynamic changes in pressure at the wellhead and in the reservoir in real time during the injection process; (6) After the acid injection is completed, the well is shut in and left to stand. The composite acid solution reacts fully with the reservoir minerals, forming a high-permeability zone consisting of an acidizing permeation enhancement zone and an acidizing transition zone in the near-wellbore area around the wellbore, while restoring the formation pressure. (7) Inject CO2 into the target aquifer after acid treatment to form an initial CO2 gasbag; (8) Perform CO2 energy storage cycle operation, wherein the cycle operation includes a gas injection energy storage stage and an extraction energy release stage; (9) Monitor the wellhead temperature, wellhead pressure, CO2 injection rate and CO2 extraction rate during the gasbag filling period and the circulating energy storage period, and calculate and evaluate the reservoir's injection capacity and extraction capacity.

2. The method for enhancing the permeability and injection-production capacity of aqueduct compressed CO2 energy storage reservoirs according to claim 1, characterized in that, In the composite acid system, the mass concentration of HCl is 5% to 30%, and the mass concentration of HF is 1% to 5%.

3. The method for enhancing the permeability and injection-production capacity of aqueduct compressed CO2 energy storage reservoirs according to claim 1, characterized in that, In step (5), the injection time of the composite acid solution is 1 to 10 days, and the injection rate is determined according to the thickness, permeability and mineral composition parameters of the target aquifer.

4. The method for enhancing the permeability and injection-production capacity of aqueduct compressed CO2 energy storage reservoirs according to claim 1, characterized in that, In step (6), the well is left to stand for 1 to 10 days.

5. The method for enhancing the permeability and injection-production capacity of aqueduct compressed CO2 energy storage reservoirs according to claim 1, characterized in that, The injection capacity mentioned in step (9) is characterized by the injection capacity index, which is the ratio of the CO2 injection rate to the wellhead pressure increment at the corresponding injection stage. The injection stage includes the gasbag filling injection stage and the circulating energy storage gas injection stage.

6. The method for enhancing the permeability and injection-production capacity of aqueduct compressed CO2 energy storage reservoirs according to claim 1, characterized in that, The extraction capacity mentioned in step (9) is characterized by the extraction capacity index, which is the ratio of the CO2 extraction rate to the wellhead pressure increment at the corresponding extraction stage.

7. The method for enhancing the permeability and injection-production capacity of aqueduct compressed CO2 energy storage reservoirs according to claim 1, characterized in that, The acidizing and permeation-enhancing zone is a near-wellbore strong dissolution reaction zone adjacent to the wellbore, and the acidizing transition zone is a weak dissolution reaction zone distributed around the acidizing and permeation-enhancing zone.

8. The method for enhancing the permeability and injection-production capacity of aqueduct compressed CO2 energy storage reservoirs according to claim 1, characterized in that, The ground circulation system includes a CO2 working fluid circulation branch and a heat exchange medium circulation branch; The CO2 working fluid circulation branch is equipped with a first-stage compressor, a first-stage cooler, a second-stage compressor, a second-stage heat exchanger, a CO2 injection valve, a wellbore, a CO2 extraction valve, a first-stage heater, a first-stage expander, a second-stage heater, a second-stage expander, and a generator. Along the flow direction of CO2 injection into the reservoir, the first-stage compressor, first-stage cooler, second-stage compressor, second-stage heat exchanger, CO2 injection valve, and wellbore are connected in series. Along the flow direction of CO2 extraction from the well, the wellbore, CO2 extraction valve, first-stage heater, first-stage expander, second-stage heater, and second-stage expander are connected in series. Both the first-stage and second-stage expanders are connected to the generator for power transmission. The heat exchange medium circulation branch is equipped with a hot flow side mixer, a heat storage tank, a cold flow side converter, a cold storage tank, and heat exchange pipelines. The heat exchange medium circulation branch is connected to the first-stage cooler, the second-stage heat exchanger, the first-stage heater, and the second-stage heater for heat exchange, and is used to recover and store the compression heat of CO2, heat and extract CO2, and recover and store the expansion cold energy of CO2.

9. The method for enhancing the permeability and injection-production capacity of aqueduct compressed CO2 energy storage reservoirs according to claim 1, characterized in that, The CO2 energy storage cycle described in step (8) adopts a daily, weekly, or quarterly cycle operation mode: The daily cycle operation mode is as follows: During the off-peak period of electricity consumption, surplus electricity is used to drive the compressor to compress CO2, which is then cooled by the cooler and injected into the target aquifer to complete energy storage; During the peak period of electricity consumption, CO2 in the target aquifer is extracted to the ground, heated by the heater, and then sent to the expander to do work and drive the generator to generate electricity, thus completing energy release. The weekly cycle operation mode is as follows: CO2 is compressed and injected into energy storage on days or periods of low electricity consumption, and CO2 is extracted and released to generate electricity on days or periods of high electricity consumption. The seasonal cycle operation mode is as follows: CO2 is compressed and injected into energy storage during the off-peak season and CO2 is extracted and released to generate electricity during the peak season.

10. The method for enhancing the permeability and injection-production capacity of aqueduct compressed CO2 energy storage reservoirs according to claim 1, characterized in that, The target aquifer is a sandstone reservoir containing carbonate or aluminosilicate minerals cemented / filled.

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