A method for determining water quality and pressure parameters of high salinity mine water deep well reinjection in coordination

Abstract

The application discloses a kind of high salinity mine water deep well reinjection water quality and the coordinated determination of injection pressure method, specifically includes: collecting reinjection area geological data, hydrogeological data, groundwater sample and rock sample;Stratum i foundation hydrogeological model of reinjection is constructed;Develop reinjection high salinity mine water reinjection water chemistry numerical simulation, determine the ion component concentration threshold value, according to the ion component concentration determined configuration corresponding aqueous solution, obtain reinjection water quality parameter;According to the set reinjection flow and the service life of reinjection well, the total amount of design reinjection of reinjection well is calculated, and the corresponding limit pressure is calculated.The application realizes the coordinated determination of water quality index and injection limit pressure index based on the establishment of hydrogeological model, solves the problem that the past reinjection index determination relies on field practice experience determination is not rigorous, the method of the present scheme is clear in structure, logic is easy to understand, calculation process is simple, and is easy to popularize and apply.

Description

Technical Field

[0001] This invention belongs to the field of mine water treatment technology, and relates to deep well reinjection of concentrated brine, specifically to a method for the coordinated determination of water quality and pressure in deep well reinjection of high-mineralization mine water. Background Technology

[0002] Mine water in western mining areas is mostly highly salinized, with total dissolved solids (TDS) exceeding 1000 mg / L, surpassing the Class III limit of the "Groundwater Quality Standard" and the "Drinking Water Standard". Due to its high salinity and hardness, direct discharge of highly salinized mine water would have a serious impact on the environment. Therefore, exploring underground storage and reuse methods is of great significance. Deep well reinjection technology is a practical method to alleviate the problem of highly salinized mine water. This technology can significantly reduce treatment costs. In the future, with continuous technological development and expanded applications, underground storage technology for highly salinized mine water is expected to become one of the important means of in-situ protection and utilization of mine water in coal mines. However, existing technologies lack methods for determining the reinjection parameters of highly salinized mine water, and methods for determining the injection pressure and reinjected water quality during the reinjection process have not yet been established. There is an urgent need to develop a method for obtaining the reinjection parameters of highly salinized mine water to achieve efficient and safe reinjection of highly salinized mine water. Summary of the Invention

[0003] This invention provides a method for the coordinated determination of water quality and pressure in deep wells with high mineralization. It achieves the coordinated determination of water quality indicators and injection limit pressure, solving the problem of the lack of rigor in the past when the determination of reinjection indicators relied on field experience.

[0004] The technical solution adopted in this invention is as follows:

[0005] A method for the coordinated determination of water quality and injection pressure in deep mine water with high salinity includes the following steps: Step 1: Collect geological and hydrogeological data of the reinjection area, and collect groundwater and rock samples from the i-th layer of the reinjection stratum; Step 2: Based on the data collected in Step 1, select data that can reflect the basic information of the i-th layer of the reinjection stratum and construct a basic hydrogeological model of the i-th layer of the reinjection stratum. Step 3: Perform a full water quality analysis on the i-th layer groundwater sample collected in Step 1, perform rock mechanics and permeability analysis on the i-th layer rock sample collected, improve the basic hydrogeological model of the i-th layer established in Step 2 based on the analysis results, and establish an accurate hydrogeological model of the i-th layer that includes information on water quality, water level, water temperature, porosity and rock composition of the i-th layer. Step 4: Based on the parameters in the i-th layer hydrogeological model established in Step 3, conduct a numerical simulation of the hydrochemical properties of reinjected high-salinity mine water, determine the concentration threshold of reinjected ion components, and prepare corresponding aqueous solutions according to the determined ion component concentrations. Step 5: Conduct reinjection tests, detect the water quality components of the mixed water samples obtained from the reinjection tests, optimize the concentration threshold of ion components in the reinjected water, and obtain the reinjected water quality parameters; Step 6: Based on the rock mechanics parameters, hydrogeological parameters, and reinjection well design parameters in the i-th layer accurate hydrogeological model established in Step 3, determine the minimum injection pressure. and the original strata permeability coefficient According to the reinjection well design parameters, the diameter of the reinjection section... The radius of influence of the reinjection is calculated based on the reinjection flow rate Q. and the ultimate reserves of the i-th stratum ; Step 7: Set the ground temperature of the i-th layer An indoor dynamic reinjection test model was built to assess the reinjection water quality, using the lowest injection pressure obtained in step 6. Start injection, gradually increasing the pressure to the maximum design pressure of the injection pump. Multiple sets of reinjection simulation tests were conducted, and the reinjection pressure was recorded. Changes in internal seepage characteristics and porosity The corresponding changes are plotted to fit the image. The functional relationship, substituted into the limit reserves The calculation equation yields the relationship function among the three. ; Step 8: Calculate the designed total reinjection volume S of the reinjection well based on the set reinjection flow rate Q and the set service life A of the reinjection well. j Substitute into the relational function obtained in step 7 The corresponding ultimate pressure P is calculated. j ; Step 9: Determine the parameters required for the back injection based on the parameters obtained in Step 5 and Step 8.

[0006] Optionally, the i-th layer of basic hydrogeological model constructed in step 2 is specifically as follows: Step 2.1: The collected data should include at least the stratigraphic distribution characteristics, different stratigraphic thickness characteristics, and different stratigraphic lithological characteristics of the reinjection well area; Step 2.2: Based on the reinjection formation layer i designed for the reinjection well, construct a basic hydrogeological model, which should at least include the thickness of the medium-coarse sandstone layer i. Aquifer thickness and the static water level of the i-th aquifer .

[0007] Optionally, the detailed hydrogeological model of the i-th layer constructed in step 3 is as follows: Step 3.1: The detailed hydrogeological model of the i-th layer should include at least the complete analysis parameters of the groundwater quality of the i-th layer, including water temperature. pH Total dissolved solids Seven common ion concentration values Characteristic ion concentration values ; Step 3.2: The detailed hydrogeological model of the i-th layer should at least include the rock mechanics test parameters and surrounding rock composition parameters of the i-th layer, including rock permeability. and composition of surrounding rock components .

[0008] Optionally, the hydrochemical numerical simulation conducted in step 4 specifically includes: Step 4.1: The basic requirements for the reinjection water quality parameters are that the water quality indicators of the reinjection water and the mixed water after reinjection should not be higher than the background water temperature of the i-th layer. pH Total dissolved solids Seven common ion concentration values Characteristic ion concentration values ; Step 4.2: The first step in the hydrochemical simulation of the reinjected water is to calculate the water quality parameters of the reinjected water. Characteristic ion concentration values In the numerical simulation software, the groundwater mixing module and the dissolution-sedimentation module were called. Groundwater quality parameters after mixing and sedimentation-dissolution processes were calculated using different mixing ratios: mine water:groundwater = 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, and 1:9. , , , and ; Step 4.3: Apply the water quality indicators of the reinjected mixed water obtained from the numerical simulation in Step 4.2. , , , and Compared with the background value of groundwater quality in the i-th aquifer, when When the reinjected water quality meets the reinjection requirements, it is recorded as follows: ; Step 4.4: Calculate the water quality parameters based on Step 4.3. Prepare an aqueous solution of the corresponding concentration for use as reinjection water in the reinjection test.

[0009] Optionally, the reinjection test described in step 5 is as follows: Step 5.1: Build an indoor physical model for high-mineralization mine water reinjection test. Add the test reinjection water prepared in step 4.4 to the test device and conduct a long-term reinjection test. Take samples for testing every 1 day and take the solution after the test for water quality testing. Step 5.2: Specifically, the indoor high-salinity mine water reinjection test is a long-cycle test, with each cycle lasting 30 days. Within each cycle, each day is calculated as follows: The concentration-ratio solution was continuously reinjected, and a mixed water sample was taken every day after the experiment for a complete water quality analysis to obtain the corresponding water quality parameters, which were denoted as follows: Record its parameter indicators within one period. The changes; Step 5.3: Based on parameter indicators within a period Fit the changes The function of parameter changes predicts long-term backflow. The concentration changes, if long-term reinjection The predicted concentration value is less than ,but These are the parameters for the reinjected water quality.

[0010] Optional, in step 6 The calculation formula is as follows: ; In the formula The ultimate water storage capacity of the formation, in cubic meters (m³). 3 , The volume of water stored in the formation is expressed in cubic meters (m³). 3 , , These are the rock matrix porosity and the isothermal compressibility of water, respectively, in MPa. -1 , The porosity of the reservoir. The average saturation of water, The difference between the water injection pressure and the static water pressure at the orifice, expressed in MPa. When calculating reservoir volume, the reinjection influence area is generalized to a region with a radius of [missing information]. A cylindrical aquifer, in the formula The formula for calculating the volume of water stored in a formation is as follows: ; In the formula The radius of influence of the reinjection is in meters. The effective thickness of the aquifer is expressed in meters (m).

[0011] Optionally, the relationship function among the three parties described in step 7. The method for determining it is as follows: A reinjection simulation experiment was conducted, with pressure P set as the independent variable and porosity as the independent variable. Set as the dependent variable and record different pressures during the injection process. Corresponding different porosities The value, plot Image, fitted to obtain Empirical formula; substitute the fitted empirical formula into step 6. The calculation formula can be used to obtain the result. The relationship between the three.

[0012] Optionally, the method for determining the ultimate pressure in step 8 is as follows: calculate the design water injection volume according to the formula. The formula is as follows: ; A represents the design service period in years, and Q represents the design injection flow rate in meters. 3 / h, t is the daily designed reinjection time, h; the designed reinjection volume... Substitute the three factors into the fitted function relationship to calculate the ultimate pressure. .

[0013] Compared with the prior art, the present invention has the following advantages: Based on the establishment of a hydrogeological model, this invention achieves the coordinated determination of water quality indicators and water injection limit pressure indicators, solving the problem of the lack of rigor in the past determination of reinjection indicators relying on field practice experience. The method proposed in this solution has a clear structure, easy-to-understand logic, and simple calculation process, making it easy to promote and apply. Attached Figure Description

[0014] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart of the method for collaboratively determining the water quality and pressure parameters of deep well reinjection of high-salinity mine water according to the present invention. Figure 2 This is the basic hydrogeological model of the study area in Example 1; Figure 3 The changes in conventional water quality parameters in the mixed simulation experiment of Example 1; Figure 4 This is a graph showing the trend of TDS concentration changes in the reinjection test in Example 1; Figure 5 For the reinjection test P- in Example 1 Fitted plot. Detailed Implementation

[0015] It should be noted that, unless otherwise specified, all devices, components, equipment and methods in this invention adopt components, equipment and methods known in the prior art.

[0016] Following the above technical solutions, specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0017] Combination Figure 1 The present invention provides a method for the coordinated determination of water quality and injection pressure in deep mine water with high mineralization, which specifically includes the following steps: Step 1: Collect geological and hydrogeological data of the reinjection area, and collect groundwater and rock samples from the i-th layer of the reinjection stratum; Step 2: Based on the geological data, hydrogeological data, and reinjection well data collected in Step 1, select data that can reflect the basic information of the i-th layer of the reinjection formation, and construct a basic hydrogeological model of the i-th layer of the reinjection formation, including the basic hydrogeological information of the i-th layer such as burial depth and aquifer thickness. Step 3: Perform a full water quality analysis on the i-th layer groundwater sample collected in Step 1, perform rock mechanics and permeability analysis on the i-th layer rock sample collected, improve the basic hydrogeological model of the i-th layer established in Step 2 based on the analysis results, and establish an accurate hydrogeological model of the i-th layer that includes information on water quality, water level, water temperature, porosity, and rock composition of the i-th layer. Step 4: Based on the parameters in the i-th layer hydrogeological model established in Step 3, conduct a numerical simulation of the hydrochemical properties of reinjected high-salinity mine water, determine the concentration threshold of reinjected ion components, and prepare corresponding aqueous solutions according to the determined ion component concentrations. Step 5: Conduct reinjection tests, detect the water quality components of the mixed water samples obtained from the reinjection tests, optimize the concentration threshold of ion components in the reinjected water, and obtain the reinjected water quality parameters; Step 6: Based on the rock mechanics parameters (porosity and rock composition), hydrogeological parameters (water quality, water level, and water temperature of the i-th layer) and reinjection well design parameters (reinjection section well diameter) established in Step 3 in the accurate hydrogeological model of the i-th layer. and reinjection flow rate Q (m 3 / h), determine the minimum injection pressure and the original strata permeability coefficient According to the reinjection well design parameters, the diameter of the reinjection section... The radius of influence of the reinjection is calculated based on the reinjection flow rate Q. and the ultimate reserves of the i-th stratum ; Step 7: Based on the parameters obtained in Step 6, set the geothermal temperature of the i-th layer. An indoor dynamic reinjection test model was built to assess the reinjection water quality, using the lowest injection pressure obtained in step 6. Start injection, gradually increasing the pressure to the maximum design pressure of the injection pump. Multiple sets of reinjection simulation tests were conducted, and the reinjection pressure was recorded. Changes in internal seepage characteristics and porosity The corresponding changes are plotted to fit the image. The functional relationship, substituted into the limit reserves The calculation equation yields the relationship function among the three. ; Step 8: Calculate the designed total reinjection volume S of the reinjection well based on the set reinjection flow rate Q and the set service life A of the reinjection well. j Substitute into the relational function obtained in step 7 The corresponding ultimate pressure P is calculated. j ; Step 9: Determine the parameters required for the back injection based on the parameters obtained in Step 5 and Step 8.

[0018] In this invention, the i-th basic hydrogeological model constructed in step 2 is specifically as follows: Step 2.1: Collected geological and hydrogeological data should include the stratigraphic distribution characteristics, thickness characteristics of different stratigraphic layers, and lithological characteristics of different stratigraphic layers in the reinjection well area.

[0019] Step 2.2: Based on the reinjection formation layer i designed for the reinjection well, construct a basic hydrogeological model, which should at least include the thickness of the medium-coarse sandstone layer i. Aquifer thickness and the static water level of the i-th aquifer .

[0020] In this invention, the i-th layer of refined hydrogeological model constructed in step 3 is specifically as follows: Step 3.1: The detailed hydrogeological model of the i-th layer should include at least the complete analysis parameters of the groundwater quality of the i-th layer, including water temperature. pH Total dissolved solids Seven common ion concentration values Characteristic ion concentration values ; Step 3.2: The detailed hydrogeological model of the i-th layer should at least include the rock mechanics test parameters and surrounding rock composition parameters of the i-th layer, including rock permeability. and composition of surrounding rock components .

[0021] In this invention, the hydrochemical numerical simulation carried out in step 4 specifically includes: Step 4.1: The basic requirements for the reinjection water quality parameters are that the water quality indicators of the reinjection water and the mixed water after reinjection should not be higher than the background water temperature of the i-th layer. pH Total dissolved solids Seven common ion concentration values Characteristic ion concentration values ; Step 4.2: The first step in the hydrochemical simulation of reinjected water is to calculate the water quality parameters of the reinjected water. Characteristic ion concentration values In the numerical simulation software, the groundwater mixing module and the dissolution-sedimentation module were called. Groundwater quality parameters after mixing and sedimentation-dissolution processes were calculated using different mixing ratios: mine water:groundwater = 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, and 1:9. , , , and ; Step 4.3: Apply the water quality indicators of the reinjected mixed water obtained from the numerical simulation in Step 4.2. , , , and Compared with the background value of groundwater quality in the i-th aquifer, when When the reinjected water quality meets the reinjection requirements, it is recorded as follows: ; Step 4.4: Calculate the water quality parameters based on Step 4.3. Prepare an aqueous solution of the corresponding concentration for use as reinjection water in the reinjection test.

[0022] In this invention, the reinjection test in step 5 is specifically as follows: Step 5.1: Build an indoor physical model for high-mineralization mine water reinjection test. Add the test reinjection water prepared in step 4.4 to the test device and conduct a long-term reinjection test. Take samples for testing every 1 day and take the solution after the test for water quality testing. Step 5.2: Specifically, the indoor high-salinity mine water reinjection test is a long-cycle test, with each cycle lasting 30 days. Within each cycle, each day is calculated as follows: The concentration-ratio solution was continuously reinjected, and a mixed water sample was taken every day after the experiment for a complete water quality analysis to obtain the corresponding water quality parameters, which were denoted as follows. Record its parameter indicators within one period. The changes; Step 5.3: Based on parameter indicators within a period Fit the changes The function of parameter changes predicts long-term backflow. The concentration changes, if long-term reinjection The predicted concentration value is less than ,but These are the parameters for the reinjected water quality.

[0023] Step 6 The calculation formula is as follows: ; In the formula The ultimate water storage capacity of the formation, in cubic meters (m³). 3 , The volume of water stored in the formation is expressed in cubic meters (m³). 3 , , These are the rock matrix porosity and the isothermal compressibility of water, respectively, in MPa. -1 , The porosity of the reservoir. The average saturation of water, The difference between the water injection pressure and the static water pressure at the orifice, expressed in MPa. When calculating reservoir volume, the reinjection influence area is generalized to a region with a radius of... A cylindrical aquifer, in the formula The formula for calculating the volume of water stored in a formation is as follows: ; In the formula The radius of influence of the reinjection is in meters. The effective thickness of the aquifer is given in meters (m); in the formula... The radius of influence of the pumping test in hydrogeological experiments is calculated using the formula.

[0024] In this invention, the relationship function of the three in step 7 The method for determining it is as follows: A reinjection simulation experiment was conducted, with pressure P set as the independent variable and porosity as the independent variable. Set as the dependent variable and record different pressures during the injection process. Corresponding different porosities The value, plot Image, fitted to obtain Empirical formula; substitute the fitted empirical formula into step 6. The calculation formula can be used to obtain the result. The relationship between the three.

[0025] In this invention, the method for determining the ultimate pressure in step 8 is as follows: the designed water injection volume is calculated according to the formula. The formula is as follows: ; A represents the design service period in years, and Q represents the design injection flow rate in meters. 3 / h, t is the daily designed reinjection time, h; the designed reinjection volume... Substitute the three factors into the fitted function relationship to calculate the ultimate pressure. .

[0026] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0027] Example 1: This embodiment presents a method for the coordinated determination of water quality and pressure parameters in deep mine water reinjection, which includes the following steps: Step 1: Collect regional geological and hydrogeological data of Ningzheng mining area, and collect groundwater and rock samples from the i-th layer of reinjected strata.

[0028] Step 2.1: Based on the geological data, hydrogeological data, and reinjection well data collected in Step 1, select data that can reflect the basic information of the i-th layer of the reinjection formation, and construct a basic hydrogeological model of the i-th layer of the reinjection formation, including basic hydrogeological information of the i-th layer such as burial depth and aquifer thickness (e.g., Figure 2 ); Step 2.2: Based on the reinjection well design, the i-th layer of the reinjection formation is the Liujiagou Formation. A basic hydrogeological model is constructed, in which the thickness H of the coarse sandstone in the i-th layer of the Liujiagou Formation is given. i =411m, denoted as the aquifer thickness M. i =411m and the static water level of the i-th aquifer is h0=1087m.

[0029] Step 3.1: The complete analysis parameters of the groundwater quality in the i-th layer of the refined hydrogeological model are shown in Table 1. These parameters include the water temperature T. i pH i Total dissolved solids (TDS) i Concentration values ​​of seven common ions C (K, Na, Ca, Mg, Cl, SO4, HCO3) i Characteristic ion concentration value C (F, Fe) i .

[0030] Table 1 Groundwater quality parameters of Liujiagou Formation

[0031] Step 3.2: Test the mechanical parameters of the i-th layer of rock and the parameters of the surrounding rock composition, including rock permeability. i and the composition of surrounding rock components μ i See Tables 2 and 3.

[0032] Table 2. Mineral composition analysis results of the Liujiagou Formation

[0033] Table 3. Results of porosity and permeability tests on the Liujiagou Formation rocks.

[0034] Step 4.1: Background water temperature T of the i-th layer, Liujiagou Formation i =65℃, pH i =6.43, Total Dissolved Solids (TDS) i =29455.83 mg / L, concentration values ​​of seven common ions C (K+, Na+, Ca+, Mg+, Cl+, SO42-, HCO3-) i = (5741.58, 11550.33, 66.52, 17256.25, 2222.08, 165.17) mg / L, characteristic ion concentration value C (F, Fe) i = (4.1, 1.47) mg / L.

[0035] Step 4.2: The water quality parameters C (K+Na, Ca, Mg, Cl, SO4, HCO3) of the high-salinity mine water to be reinjected. j = (626.19, 124, 29.2, 427, 1010, 148.78) mg / L and characteristic ion concentration value C (F, Fe, NO3) j = (0.19, 0.13) mg / L are both lower than the background value C of the water quality parameter of the Liujiagou Formation. i and characteristic ion concentration value C i The basic requirements for reinjected water quality are met. The water quality parameter C of the mine water to be reinjected is... j C j and the background value C of the Liujiagou Formation i C i The groundwater mixing module was called into the numerical simulation software. Based on the characteristic components of the mixed solution, the mixing and dissolution-precipitation modules were determined. The groundwater quality parameters after mixing and precipitation-dissolution were calculated and are shown in Tables 4 and 5.

[0036] Table 4. Conventional ionic parameters of the mixed water sample after reinjection.

[0037] Table 5 Characteristic ionic parameters of the mixed water sample after reinjection

[0038] Step 4.3: Based on Table 4, the changes in conventional water quality parameters in the mixed simulation experiment are shown below. Figure 3 As shown, when reinjecting at any ratio, the single conventional water quality parameter will not exceed the water quality background value of the i-th layer Liujiagou Formation. However, when the ratio of reinjected mine water to the in-situ aquifer exceeds 3:7, the TDS concentration of the mixed water sample is greater than that of the original aquifer groundwater. Therefore, ensuring that the reinjection mixing ratio does not exceed 3:7 can ensure that the conventional water quality parameters do not exceed the standard.

[0039] As shown in Table 5, after mixing in any proportion, the concentration of characteristic ions in the mixed water is lower than the background value of the groundwater in the aquifer before mixing, satisfying C. l <C i The basic requirements for groundwater quality parameters after reinjection are as follows. Combining the characteristics of conventional ion concentrations after mixing, it can be concluded that when reinjection is carried out at a ratio not exceeding 3:7 (mine water:groundwater), the following parameters are met: {T, pH, TDS, C, C...} } l <{T, pH, TDS, C, C } i The requirements are the critical control parameters for the reinjected mine water quality. By substituting the mixing ratio, the background groundwater value of the i-th layer Liujiagou Formation, and the concentration after mixing into the numerical simulation software, the critical control parameters {T, pH, TDS, C, C} of the mine water before mixing are simulated in reverse. } l0 ={43, 7.9, 7871, C (2070, 410, 96, 1409, 3423, 491) (mg / L), C (0.63, 0.43) (mg / L)}.

[0040] Step 4.4: Based on the water quality parameters calculated in Step 4.3 {T, pH, TDS, C, C } l0 Prepare an aqueous solution of the corresponding concentration for use as reinjection water in the reinjection test.

[0041] Step 5: The trend of water quality parameters of the mixed water sample measured every day in the long-term reinjection test is as follows: Figure 4 As shown, by Figure 3 It can be seen that the TDS concentration of the reinjected mixed water initially decreases rapidly and then gradually stabilizes. Based on the fitted curve, the long-term stable TDS value of the reinjected mixed water is predicted to be TDS. 长期 =8100 mg / L, which is much lower than the background TDS value of the reinjected Liujiagou Formation. i=29455.83mg / L, therefore this water quality parameter meets the reinjection water quality requirements, namely {T, pH, TDS, C, C } l0 These are the parameters for the reinjected water quality.

[0042] Step 6: Based on the rock mechanics parameters, hydrogeological parameters, and reinjection well design parameters in the accurate hydrogeological model of the i-th layer established in Step 3, determine the minimum injection pressure P0 = 11 MPa and the original formation permeability coefficient K0 = 1.67 × 10⁻⁶. -3 m / d, reinjection section diameter r of reinjection well w =0.0762m, Design reinjection flow rate Q=150 (m³ / s) 3 / h), calculated using the Kusakin formula, the influence radius of reinjection is R0 = 935m, which is the effective thickness M of the aquifer. i =411m, substituting into the formula, the volume of water stored in the reinjected Liujiagou Formation is calculated. = = π (935) 2 411 = 112,822 million m 3 S w The average saturation of water is denoted by a constant of 100%; C m rock matrix pores (MPa) -1 The value is 9.55 × 10 -4 MPa -1 C w The isothermal compressibility coefficient of water (MPa) -1 The value is 4.6 × 10 MPa -1 , The reservoir porosity, obtained from Table 3, is 2.2%, and the formation pressure is based on 150m. 3 The pressure change during the / h water injection test was analyzed, and ΔP was determined to be 9.8MPa. Substituting this into the formula, the ultimate water storage capacity S was calculated. max =4,623,800 m 3 .

[0043] Step 7: Based on the parameters obtained in Step 6, set the geothermal temperature of the i-th layer, Liujiagou Formation, T0 = 65℃ to conduct a reinjection test. Start with the lowest injection pressure P0 = 11MPa, and conduct tests at 12MPa, 13MPa, and 14MPa (increasing the pressure by 1MPa for each test group) until the maximum design pressure of the injection pump, P. max Multiple reinjection tests were conducted at a pressure of 20 MPa over a 30-day period, recording the internal porosity caused by changes in reinjection pressure P during the test. The corresponding changes are used to draw an image. Figure 5As the reinjection pressure P increases, the porosity of the core in the test apparatus increases. Continued to decrease. Figure 5 The coefficient of determination (R²) in the fitted curve 2 The optimal value is R. 2 Cubic =0.997 (red line in the figure), reflecting the formation porosity during reinjection within the pump's design pressure range. The variation of reinjection pressure P follows a pattern consistent with the fitted Cubic function, and the relationship is as follows: ; P- Substituting relational expression into S max From the formula for the ultimate reserves, we can obtain... The relationship between the three is as follows: ; Step 8: Calculate the design water injection volume S according to the formula. j In the formula, A represents the design service life of 4 years, and Q represents the design reinjection flow rate of 150m³. 3 / h, where t is the designed daily reinjection time of 20h, and substituting these values ​​into the formula, we obtain the designed total reinjection S. j =4.38 million m 3 .

[0044] The total designed reinjection volume S j =4.38 million m 3 Substitution The ultimate reinjection pressure P is obtained by calculating the relationship between the three factors. j =15.1MPa.

[0045] Step 9: Therefore, based on this method, the water quality threshold for reinjection of a high-mineralization mine water in a certain mine in the Ningzheng mining area is finally determined as {T, pH, TDS, C, C}. } l0 ={43℃, 7.9, 7871 mg / L, C(2070, 410, 96, 1409, 3423, 491) (mg / L), C (0.63, 0.43) (mg / L)}, reinjection limit pressure is P j =15.1MPa.

[0046] Although the illustrative specific embodiments of the present invention have been described above to enable those skilled in the art to understand the invention, it should be understood that the invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the invention as defined and determined by the appended claims, and all inventions utilizing the concept of the present invention are protected.

Claims

1. A method for the coordinated determination of water quality and injection pressure in deep wells of high-salinity mine water, characterized in that, Specifically, the steps include the following: Step 1: Collect geological and hydrogeological data of the reinjection area, and collect groundwater and rock samples from the i-th layer of the reinjection stratum; Step 2: Based on the data collected in Step 1, select data that can reflect the basic information of the i-th layer of the reinjection stratum and construct a basic hydrogeological model of the i-th layer of the reinjection stratum. Step 3: Perform a full water quality analysis on the i-th layer groundwater sample collected in Step 1, perform rock mechanics and permeability analysis on the i-th layer rock sample collected, improve the basic hydrogeological model of the i-th layer established in Step 2 based on the analysis results, and establish an accurate hydrogeological model of the i-th layer that includes information on water quality, water level, water temperature, porosity and rock composition of the i-th layer. Step 4: Based on the parameters in the i-th layer hydrogeological model established in Step 3, conduct a numerical simulation of the hydrochemical properties of reinjected high-salinity mine water, determine the concentration threshold of reinjected ion components, and prepare corresponding aqueous solutions according to the determined ion component concentrations. Step 5: Conduct reinjection tests, detect the water quality components of the mixed water samples obtained from the reinjection tests, optimize the concentration threshold of ion components in the reinjected water, and obtain the reinjected water quality parameters; Step 6: Based on the rock mechanics parameters, hydrogeological parameters, and reinjection well design parameters in the i-th layer accurate hydrogeological model established in Step 3, determine the minimum injection pressure. and the original strata permeability coefficient According to the reinjection well design parameters, the diameter of the reinjection section... The radius of influence of the reinjection is calculated based on the reinjection flow rate Q. and the ultimate reserves of the i-th stratum ; Step 7: Set the ground temperature of the i-th layer An indoor dynamic reinjection test model was built to assess the reinjection water quality, using the lowest injection pressure obtained in step 6. Start injection, gradually increasing the pressure to the maximum design pressure of the injection pump. Multiple sets of reinjection simulation tests were conducted, and the reinjection pressure was recorded. Changes in internal seepage characteristics and porosity The corresponding changes are plotted to fit the image. The functional relationship, substituted into the limit reserves The calculation equation yields the relationship function among the three. ; Step 8: Calculate the designed total reinjection volume S of the reinjection well based on the set reinjection flow rate Q and the set service life A of the reinjection well. j Substitute into the relational function obtained in step 7 The corresponding ultimate pressure P is calculated. j ; Step 9: Determine the parameters required for the back injection based on the parameters obtained in Step 5 and Step 8.

2. The method for jointly determining the quality and injection pressure of deep well reinjection water in high-salinity mine water according to claim 1, characterized in that, The i-th layer of basic hydrogeological model constructed in step 2 is as follows: Step 2.1: The collected data should include at least the stratigraphic distribution characteristics, different stratigraphic thickness characteristics, and different stratigraphic lithological characteristics of the reinjection well area; Step 2.2: Based on the reinjection formation layer i designed for the reinjection well, construct a basic hydrogeological model, which should at least include the thickness of the medium-coarse sandstone layer i. Aquifer thickness and the static water level of the i-th aquifer .

3. The method for jointly determining the quality and injection pressure of reinjected water in deep mine water with high salinity according to claim 1 or 2, characterized in that, The detailed hydrogeological model of the i-th layer constructed in step 3 is as follows: Step 3.1: The detailed hydrogeological model of the i-th layer should include at least the complete analysis parameters of the groundwater quality of the i-th layer, including water temperature. pH Total dissolved solids Seven common ion concentration values Characteristic ion concentration values ; Step 3.2: The detailed hydrogeological model of the i-th layer should at least include the rock mechanics test parameters and surrounding rock composition parameters of the i-th layer, including rock permeability. and composition of surrounding rock components .

4. The method for jointly determining the reinjection water quality and injection pressure of deep mine water with high salinity according to claim 1 or 2, characterized in that, Step 4 involves the following water chemistry numerical simulation: Step 4.1: The basic requirements for the reinjection water quality parameters are that the water quality indicators of the reinjection water and the mixed water after reinjection should not be higher than the background water temperature of the i-th layer. pH Total dissolved solids Seven common ion concentration values Characteristic ion concentration values ; Step 4.2: The first step in the hydrochemical simulation of the reinjected water is to calculate the water quality parameters of the reinjected water. Characteristic ion concentration values In the numerical simulation software, the groundwater mixing module and the dissolution-sedimentation module were called. Groundwater quality parameters after mixing and sedimentation-dissolution processes were calculated using different mixing ratios: mine water:groundwater = 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, and 1:

9. , , , and ; Step 4.3: Apply the water quality indicators of the reinjected mixed water obtained from the numerical simulation in Step 4.

2. , , , and Compared with the background value of groundwater quality in the i-th aquifer, when When the reinjected water quality meets the reinjection requirements, it is recorded as follows: ; Step 4.4: Calculate the water quality parameters based on Step 4.

3. Prepare an aqueous solution of the corresponding concentration for use as reinjection water in the reinjection test.

5. The method for jointly determining the quality and injection pressure of reinjected water in deep mine water with high salinity according to claim 1 or 2, characterized in that, The reinjection test described in step 5 is as follows: Step 5.1: Build an indoor physical model for high-mineralization mine water reinjection test. Add the test reinjection water prepared in step 4.4 to the test device and conduct a long-term reinjection test. Take samples for testing every 1 day and take the solution after the test for water quality testing. Step 5.2: Specifically, the indoor high-salinity mine water reinjection test is a long-cycle test, with each cycle lasting 30 days. Within each cycle, each day is calculated as follows: The concentration-ratio solution was continuously reinjected, and a mixed water sample was taken every day after the experiment for a complete water quality analysis to obtain the corresponding water quality parameters, which were denoted as follows: Record its parameter indicators within one period. The changes; Step 5.3: Based on parameter indicators within a period Fit the changes The function of parameter changes predicts long-term backflow. The concentration changes, if long-term reinjection The predicted concentration value is less than ,but These are the parameters for the reinjected water quality.

6. The method for jointly determining the quality and injection pressure of reinjected water in deep mine water with high salinity according to claim 1 or 2, characterized in that, Step 6 The calculation formula is as follows: ； In the formula The ultimate water storage capacity of the formation, in cubic meters (m³). 3 , The volume of water stored in the formation is expressed in cubic meters (m³). 3 , , These are the rock matrix porosity and the isothermal compressibility of water, respectively, in MPa. -1 , The porosity of the reservoir. The average saturation of water, The difference between the water injection pressure and the static water pressure at the orifice, expressed in MPa. When calculating reservoir volume, the reinjection influence area is generalized to a region with a radius of... A cylindrical aquifer, in the formula The formula for calculating the volume of water stored in a formation is as follows: ； In the formula The radius of influence of the reinjection is in meters. The effective thickness of the aquifer is expressed in meters (m).

7. The method for jointly determining the quality and injection pressure of reinjected water in deep mine water with high salinity according to claim 1 or 2, characterized in that, The relationship function of the three mentioned in step 7 The method for determining it is as follows: A reinjection simulation experiment was conducted, with pressure P set as the independent variable and porosity as the independent variable. Set as the dependent variable and record different pressures during the injection process. Corresponding different porosities The value, plot Image, fitted to obtain Empirical formula; substitute the fitted empirical formula into step 6. The calculation formula can be used to obtain the result. The relationship between the three.

8. The method for jointly determining the quality and injection pressure of reinjected water in deep mine water with high salinity according to claim 1 or 2, characterized in that, The method for determining the ultimate pressure in step 8 is as follows: calculate the design water injection volume according to the formula. The formula is as follows: ； A represents the design service period in years, and Q represents the design injection flow rate in meters. 3 / h, t is the daily designed reinjection time, h; the designed reinjection volume... Substitute the three factors into the fitted function relationship to calculate the ultimate pressure. .

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