Method for obtaining tidal hydrogeological parameters based on offshore pumping test

Abstract

The present application discloses a method for obtaining tidal hydrogeological parameters based on offshore pumping test, comprising the following steps: Step S1: establishing a hydrogeological model; Step S2: establishing an offshore tidal influence model; Step S3: establishing an offshore hydrogeological model affected by tides: Step S4: using a generalized gradient GRG nonlinear solution method to solve the offshore hydrogeological model with tidal influence, and obtain the hydrogeological parameters and tidal interference parameters required for the offshore pumping test. The method makes full use of a large amount of pumping test observation data, and according to the generalized gradient GRG nonlinear solution algorithm, quickly solves the required parameters, and the obtained parameter results are more accurate and reliable, saving a lot of time and cost, and solving the problem of tidal interference in offshore pumping test. The method has been actually applied in a cross-sea bridge project and successfully solved the offshore pumping test problem.

Description

Technical Field

[0001] The present application relates to the field of hydrogeological technology, and in particular to a method for obtaining tidal hydrogeological parameters based on offshore pumping tests. Background Art

[0002] Groundwater has attracted much attention as one of the important influencing factors of underground space. Accurate acquisition of groundwater hydrogeological parameters plays a huge role in the safety and economy of engineering projects.

[0003] The acquisition of hydrogeological parameters is mainly based on groundwater seepage theory, and the most commonly used method is pumping test. Due to the complexity of groundwater movement, conventional groundwater flow calculation models are based on many assumptions and have strict requirements on the calculation models. In order to adapt to the calculation model, it is necessary to obtain test data that is not interfered by the outside world, and the requirements for field pumping test data are relatively high. In the early stages of economic development, the scale of engineering construction is small and mainly on land, and the interference factors are generally relatively small. By ignoring or artificially dealing with interference, the conventional pumping test calculation method can also accurately obtain hydrogeological parameters.

[0004] However, with the rapid development of the economy, the construction sites have expanded from land to ports, sea and other areas, such as cross-sea bridges, undersea tunnels, offshore wind power and other projects. Due to the very complex environmental conditions at sea, the difficulty of construction, and the great influence of tides, it is difficult to conduct pumping tests like on land under general offshore construction conditions. Even if a pumping test is carried out, since the measured water level data contains interference factors such as tides, and even the tidal interference data is far greater than the depth drawdown data of the pumping test, this type of data is not suitable for existing calculation model methods and cannot be calculated. At present, the domestic offshore hydrogeological parameters are mainly determined based on the empirical values ​​on land, which are quite arbitrary and unscientific.

[0005] In order to deal with the interference data obtained from the offshore pumping test, the commonly used method is to conduct long-term observations of the water levels of all observation wells in advance, obtain the dynamic trend of the water levels in the observation wells, and then manually pre-process and analyze the data. However, since long-term observations at sea require the construction of platforms and the provision of ships, the cost is high, it takes up a lot of time and is very uneconomical; and the situation at sea changes in a myriad of ways, the background data obtained cannot represent the background data during the pumping test; the artificial processing of data is too arbitrary and has low accuracy.

[0006] The existing offshore pumping test calculation model generally uses a simple steady flow calculation formula to simplify the calculation due to too much interference data. The disadvantages of this method are that it cannot accurately reflect the actual hydrogeological conditions due to the over-generalization of the model; some parameters such as elastic water release coefficient and overflow factor cannot be calculated; and it is impossible to predict the change of water level over time. Summary of the invention

[0007] The present application provides a method for obtaining tidal hydrogeological parameters based on offshore pumping tests, which is used to solve the technical problems that the existing calculation book model method in the prior art is not suitable for processing interference parameters related to offshore engineering; the acquisition of data required by the existing calculation method requires long-term observation after building a platform at sea, which is costly and time-consuming, and the obtained data cannot represent the background data during the pumping experiment; the artificially processed data is arbitrary and has low precision; the simplified calculation formula is overly generalized and cannot accurately reflect the actual hydrogeological conditions.

[0008] The present application provides a method for obtaining tidal hydrogeological parameters based on an offshore pumping test, comprising the following steps:

[0009] Step S1: Establishing hydrogeological model:

[0010] Column format:

[0011]

[0012] The solution of equation (1) is (Hantush and Jacob):

[0013]

[0014] Among them: Well function parameters Confined aquifer conductivity T = Km; leakage coefficient s is the water level drop of the observation well (m), t is the pumping time; Q is the flow rate of the pumping well; r is the distance between the observation hole and the pumping well; K is the permeability coefficient of the confined aquifer; m is the thickness of the confined aquifer; μ * is the elastic water release coefficient of the confined aquifer; m′ is the thickness of the adjacent weak permeable layer; K' is the permeability coefficient of the adjacent weak permeable layer;

[0015] Based on historical exploration data, the hydrogeological model of the leaky confined aquifer is established as follows:

[0016]

[0017] Step S2: Establishing the marine tidal impact model

[0018] According to the aquifer water level fluctuation equation at a distance x from the seawater boundary:

[0019]

[0020] Where h′ is the water level fluctuation in the piezometer; h 0 is the tidal amplitude at the boundary when x=0; x is the distance between the piezometer and the boundary; t is the calculation time; t 0 is the tidal cycle;

[0021] According to the overall wave equation of the offshore aquifer, the amplitude is attenuated relative to the tidal amplitude at the boundary, and the phase lag wave equation is superimposed to establish the aquifer water level model affected by the offshore tide:

[0022]

[0023] Where H is the tidal water level elevation of the aquifer; N is the number of tidal wave equations; A i is the amplitude of the ith tidal wave equation; ω i is the angular velocity of the i-th tidal wave equation; is the phase of the ith tidal wave equation; t is the calculation time; m is the average sea level elevation; the tidal type of the pumping test site is obtained, and the number of tidal wave equations obtained according to the tidal type is N=2~4.

[0024] Step S3: Establishing an offshore hydrogeological model affected by tides: Conducting a pumping test, observing the change of groundwater level in the pumping well at any time, and establishing an offshore hydrogeological model affected by tides based on the offshore tidal aquifer water level model (6) and the hydrogeological model of the overflowing confined aquifer (3):

[0025]

[0026] Among them, h is the water level elevation in the observation well; H is the tidal water level elevation of the aquifer; s is the water level drawdown in the observation well; t is the pumping time; Q is the flow rate of the pumping well; r is the distance between the observation hole and the pumping well; T is the hydraulic conductivity of the confined aquifer; K is the permeability coefficient of the confined aquifer; m is the thickness of the confined aquifer;

[0027] B is the overflow factor; u is the well function parameter; N is the number of tidal wave equations; A i is the amplitude of the ith tidal wave equation; ω i is the angular velocity of the i-th tidal wave equation; is the phase of the ith tidal wave equation; m is the mean sea level elevation

[0028] Step S4: The offshore hydrogeological model with tidal influence is solved by using the generalized reduced gradient GRG nonlinear solution method to obtain the hydrogeological parameters and tidal disturbance parameters required for the offshore pumping experiment.

[0029] Preferably, the operation of determining the tidal type of the pumping test site in step S2 includes the following steps:

[0030] Collect local tidal observation data or on-site tidal monitoring data, and use discrete Fourier transform to analyze the obtained tidal observation data or on-site tidal monitoring data;

[0031] According to the analysis results, the tidal type, the number of tidal wave equations, the amplitude of the tidal wave equations, and the angular velocity of the tidal wave equations are determined.

[0032] Preferably, the objective function established by the generalized reduced gradient GRG nonlinear solution method in step S4 is:

[0033]

[0034] Where: h 理论 is the theoretical value of the water level in the observation well calculated according to the offshore hydrogeological model (7) with tidal influence, h 实际 is the actual observed value of the water level in the observation well, N' is the number of observation points used for calculation at different times; σ 2 h is the theoretical value of water level in the observation well calculated according to the offshore hydrogeological model (7) with tidal influence. 理论 The actual observed value of the water level in the observation well h 实际 The variance of .

[0035] Preferably, the local optimal solution solution goal set in the generalized reduced gradient GRG nonlinear solution method in step S4 is: the objective function reaches the minimum value and σ 2 is the minimum value.

[0036] Preferably, the parameter variable range constraint value used in the generalized gradient GRG nonlinear solution method in step S4 is the result of preliminary analysis using the collected data or monitoring data.

[0037] The initial value used in the generalized reduced gradient GRG nonlinear solution method in step S4 is the starting calculation value.

[0038] Preferably, the convergence judgment condition used by the generalized reduced gradient GRG nonlinear solution method in step S4 is: if the calculation result obtained does not converge, change the initial value or boundary value and recalculate.

[0039] Preferably, in step S4, if the tide changes with time during the pumping period, a generalized, i.e., reduced gradient GRG, nonlinear solution method is used for piecewise fitting calculation according to the tidal cycle.

[0040] The beneficial effects of this application include:

[0041] 1) The method for obtaining tidal hydrogeological parameters based on offshore pumping tests provided in this application can flexibly select a suitable hydrogeological model according to the actual hydrogeological conditions, and take the influence of offshore tidal interference as part of the model to participate in the model calculation, thereby establishing an offshore pumping test calculation model. This model can make full use of existing theoretical models, and the calculation does not require the background value obtained by long-term observation of observation wells. The collected pumping test data does not need to be processed and can be directly used in this method. This method makes full use of a large amount of pumping test observation data, and according to the generalized gradient GRG nonlinear solution algorithm, the required parameters are quickly solved. The obtained parameter results are more accurate and reliable, saving a lot of time and cost, and solving the problem of tidal interference in offshore pumping tests. This method has been actually used in a certain cross-sea bridge project and successfully solved the offshore pumping test problem.

[0042] 2) The method for obtaining tidal hydrogeological parameters based on offshore pumping tests provided in this application has wide adaptability and versatility. In addition to being used at sea, it can also be used for onshore pumping tests in offshore areas affected by tides. This method can make full use of existing hydrogeological model theoretical methods and select models that meet actual hydrogeological conditions to adapt to more complex hydrogeological conditions.

[0043] 3) The method for obtaining tidal hydrogeological parameters based on offshore pumping tests provided in this application has good versatility. In addition to offshore pumping tests, it can also be used for onshore pumping tests affected by tides in offshore areas. For other pumping tests with irregular interference, the discrete Fourier transform (FFT) can be used to preliminarily analyze the main period, frequency and corresponding amplitude distribution range of the interference factors in sections to establish a mixed model. The distribution range can be used as the boundary value and initial value of the calculation to speed up the model calculation speed and accuracy.

[0044] 4) The method for obtaining tidal hydrogeological parameters based on offshore pumping tests provided in this application is low-cost. Offshore pumping tests generally require long-term observation of observation wells to obtain background values, but the cost of renting a ship for observation at sea is high, and the observed values ​​before pumping cannot represent the actual values ​​during the pumping test. The method of the invention does not require long-term observation of observation wells to obtain background values, which saves costs. Existing methods can be used to determine the offshore interference impact model and parameter boundary values ​​and initial values ​​without the need for long-term observation.

[0045] 5) The method for obtaining tidal hydrogeological parameters based on offshore pumping tests provided in this application does not require long-term observation of observation wells, which saves pumping test time and improves pumping test efficiency. This method does not require data processing and directly participates in calculation and solution, reducing the difficulty of analysis. The calculation results are more accurate and more hydrogeological parameters are obtained.

[0046] 6) The tidal hydrogeological parameter acquisition method based on offshore pumping tests provided in this application can flexibly select a suitable non-steady flow hydrogeological model according to the actual hydrogeological conditions. It does not require long-term observation of observation wells to obtain background values. The collected pumping test data does not need to be processed and can be directly used in the calculation. It makes full use of a large amount of pumping test observation data, solves more parameters based on nonlinearity, and the parameter results are more accurate and reliable, saving a lot of time and cost, and solving the problem of offshore pumping tests. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is the unsteady flow model diagram of a complete well with overflow recharge;

[0048] Figure 2 A schematic flow chart of a method for obtaining tidal hydrogeological parameters based on offshore pumping tests is provided for this application;

[0049] Figure 3 This is a fitting curve diagram of the first drawdown of the G2 observation well in the specific embodiment of the present application; DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0051] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] The technical means that are not described in detail in this application and are not used to solve the technical problems of this application are all set according to the common knowledge in the field, and can be realized in various current common knowledge settings.

[0053] Example

[0054] (1) Establishing a hydrogeological model

[0055] First, prepare the offshore pumping test equipment, then conduct the pumping test. After obtaining the pumping test data, refer to the onshore pumping test. A universal, practical, complete well unsteady flow model with overflow recharge is used. The model structure is shown in Figure 1 .

[0056] This embodiment specifically includes the following steps:

[0057] Column format:

[0058]

[0059] The solution of equation (1) is (Hantush and Jacob):

[0060]

[0061] Among them: Well function parameters Confined aquifer conductivity T = Km; leakage coefficient s is the water level drop of the observation well (m), t is the pumping time; Q is the flow rate of the pumping well; r is the distance between the observation hole and the pumping well; K is the permeability coefficient of the confined aquifer; m is the thickness of the confined aquifer; μ * is the elastic water release coefficient of the confined aquifer; m′ is the thickness of the adjacent weak permeable layer; K' is the permeability coefficient of the adjacent weak permeable layer.

[0062] According to the actual hydrogeological conditions, the hydrogeological model of the leaky confined aquifer is established as follows:

[0063]

[0064] Among them, the hydrogeological parameters include elastic water release coefficient (μ * ), hydraulic conductivity (T), and overflow coefficient (B).

[0065] The range and initial value of hydrogeological parameters can be preliminarily determined based on exploration data and empirical values. The closer the range and initial value are to the true value, the faster the subsequent calculation speed will be.

[0066] (2) Establishing a model of marine tidal impact

[0067] Establish a model of offshore tides affecting aquifer water levels:

[0068]

[0069] Where H is the tidal water level elevation of the aquifer; N is the number of tidal wave equations; A i is the amplitude of the ith tidal wave equation; ω i is the angular velocity of the i-th tidal wave equation; is the phase of the ith tidal wave equation; t is the calculation time; m is the mean sea level elevation.

[0070] According to the existing tidal cycle rules, tides are divided into semi-diurnal tides, diurnal tides and mixed tides.

[0071] Semi-diurnal tide type: There are two high tides and two low tides in one day. The tidal range of the previous high tide and low tide is roughly the same as that of the next high tide and low tide. The time of the high tide process and the low tide process is also almost equal (6 hours and 12.5 minutes). Most places in Bohai Sea, East China Sea and Yellow Sea in my country have semi-diurnal tide type.

[0072] Diurnal tide type: There is only one high tide and one low tide in one day. For example, Shantou in the South China Sea, Qinhuangdao in the Bohai Sea, etc. The Beibu Gulf in the South China Sea is a typical diurnal tide sea area in the world.

[0073] Mixed tide type: some days in a month have two high tides and two low tides, but the tidal range of the two high tides and low tides is quite different, and the duration of the high tide process and the low tide process is also different; while other days have one high tide and one low tide. Most places in the South China Sea of ​​my country have mixed tide type.

[0074] The tidal type of the pumping test site is obtained, and the number of tidal wave equations obtained according to the tidal type is N=2 to 4.

[0075] For more complex tidal influences, local public tidal observation data or on-site tidal monitoring data (such as the water level in the observation well that is far away from the pumping test well and less affected by pumping) can be collected and analyzed using discrete Fourier transform (FFT) to roughly determine the tidal type, the number of tidal wave equations, the amplitude of the tidal wave equation, and the data required for the tidal wave equation angular velocity model calculation;

[0076] (3) Establishment of offshore hydrogeological model affected by tides

[0077] Conduct pumping tests and observe the changes in groundwater levels in the pumping wells at any time. There are two factors that affect the changes in groundwater levels: one is the impact of the water level drop during offshore pumping tests, and the other is the impact of offshore tidal water levels.

[0078] The offshore hydrogeological model with tidal influence is established by combining the offshore pumping test water level drawdown with the offshore tidal water level and the offshore tidal influence model and hydrogeological model analyzed above:

[0079]

[0080]

[0081] T=Km Formula (7)

[0082] Wherein, h is the water level elevation in the observation well; H is the tidal water level elevation of the aquifer; s is the water level drawdown in the observation well; t is the pumping time; Q is the flow rate of the pumping well; r is the distance between the observation hole and the pumping well; T is the hydraulic conductivity of the confined aquifer; K is the permeability coefficient of the confined aquifer; m is the thickness of the confined aquifer; μ *is the elastic water release coefficient of the confined aquifer; B is the overflow factor; u is the well function parameter; N is the number of tidal wave equations; A i is the amplitude of the ith tidal wave equation; ω i is the angular velocity of the i-th tidal wave equation; is the phase of the ith tidal wave equation; m is the mean sea level elevation.

[0083] Hydrogeological parameters include: elastic water release coefficient (μ * ), hydraulic conductivity (T), leakage coefficient (B) and other parameters;

[0084] Tidal parameters include: Amplitude A 1 , A 2 …A n , angular velocity ω 1 ,ω 2 …ω n , Phase Parameters such as average water level elevation (m)

[0085] (4) Calculation of offshore tidal hydrogeological model parameters:

[0086] Establish the objective function: theoretical value and observed value variance:

[0087]

[0088] Among them, h 理论 is the theoretical value of the water level in the observation well calculated according to the offshore hydrogeological model (5) with tidal influence, h 实际 is the actual observed value of the water level elevation of the observation well, and N' is the number of observation points used for calculation.

[0089] h 实际 In an offshore environment, in an observation well, the measured water level distance is converted into water level elevation using water level measuring equipment at a specified time. That is, the distance from the wellhead to the water level in the observation well is first measured using the water level measuring equipment, and then the measured water level distance is subtracted from the wellhead elevation to convert the water level distance in the observation well into the water level elevation value h. 实际 .

[0090] The parameters of the above equations are mainly:

[0091] 1) Hydrogeological parameters involved in the hydrogeological model: elastic water release coefficient (μ * ), hydraulic conductivity (T), leakage coefficient (B) and other parameters;

[0092] 2) Tidal disturbance affects the tidal parameters of the model: Amplitude A 1 , A 2 …A n , angular velocity ω1 ,ω 2 …ω n , Phase Parameters such as average water level elevation (m)

[0093] The above equation is a nonlinear equation with many parameters and is difficult to solve. The generalized reduced gradient GRG nonlinear solution method can be used, that is, according to the change of the input value (variable) and the rate of change of the objective function, it is judged whether a local optimal solution is obtained. If a local optimal solution is obtained, the search is stopped. It is a better algorithm for solving constrained minimization problems.

[0094] Set the error precision: if the error precision is less than this value, the calculation ends;

[0095] Select the solution algorithm: If there are many parameters and it is a nonlinear equation, select the generalized reduced gradient GRG nonlinear solution method;

[0096] Set the goal: minimum value of the objective function, and σ 2 Find the minimum value

[0097] Parameter boundary value and initial value: The results of the preliminary analysis of the collected data or monitoring data are used as the parameter variable range constraint value, and the initial value is used as the starting calculation value;

[0098] Solution calculation: The closer the initial value is to the theoretical value, the faster the solution speed;

[0099] Determine convergence: If the result does not converge, change the initial value or boundary value and recalculate;

[0100] Parameter analysis and verification: Analyze parameter values ​​and minimum values ​​of objective functions to determine the reliability of results;

[0101] Calculation ends: the variance of the parameters and the objective function meets the requirements, and the calculation ends;

[0102] Establish an offshore tidal hydrogeological model: Based on the calculated parameters, establish offshore tidal hydrogeological parameters affected by tides.

[0103] Considering that the pumping time is long and the tide will change over time, the calculation can be performed by segmented fitting according to the tidal cycle.

[0104] (5) Practical application cases

[0105] In a cross-sea bridge project in Dalian Bay, the range of hydrogeological parameters was determined based on the on-site regional data. Through the analysis of the observation well data and public data that were least affected by the pumping test, the tide at the proposed project location belonged to the all-day tide type, N = 2, and the range of tidal-related parameters was determined. The generalized reduced gradient GRG nonlinear solution method was used to solve the hydrogeological parameters and tidal interference parameters in the offshore hydrogeological model with tidal influence. The fitting solution results of various parameters obtained in this embodiment are shown in Table 1:

[0106] Table 1 Parameter fitting solution results

[0107]

[0108] The hydrogeological model of the project affected by tides in this embodiment is:

[0109]

[0110] The generalized reduced gradient GRG nonlinear solution method was adopted and a large amount of pumping test data were used to fit and solve the model, and the hydrogeological parameters and tidal parameters were accurately and quickly obtained.

[0111] The construction conditions were simulated and predicted using corresponding parameters, which were basically consistent with the results of the actual pumping test and effectively solved the problem of offshore pumping test.

[0112] The simulation results obtained by the method provided by this application and the data obtained by the actual measurement results are as follows Figure 3 As shown in the figure, it can be seen that the water level elevation actually measured in the observation well and the calculated water level elevation obtained by the model simulation results of the method provided by the present application have a good fitting effect and a small error, which indicates that the method provided by the present application can better obtain the required parameters.

[0113] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for obtaining tidal hydrogeological parameters based on offshore pumping tests, It is characterized in that The following steps are involved: Step S1: Establishing hydrogeological model: Column format: The solution of equation (1) is: Among them: Well function parameters Confined aquifer conductivity T = K·m; leakage coefficient s is the water level drop of the observation well, t is the pumping time; Q is the flow rate of the pumping well; r is the distance between the observation hole and the pumping well; K is the permeability coefficient of the confined aquifer; m is the thickness of the confined aquifer; μ * is the elastic water release coefficient of the confined aquifer; m′ is the thickness of the adjacent weak permeable layer; K' is the permeability coefficient of the adjacent weak permeable layer; According to the actual hydrogeological conditions, the hydrogeological model of the leaky confined aquifer is established as follows: Step S2: Establishing the marine tidal impact model According to the aquifer water level fluctuation equation at a distance x from the seawater boundary: Where h′ is the water level fluctuation in the piezometer; h 0 is the tidal amplitude at the boundary when x=0; x is the distance between the piezometer and the boundary; t is the calculation time; t 0 is the tidal cycle; According to the overall wave equation of the offshore aquifer, the amplitude is attenuated relative to the tidal amplitude at the boundary, and the phase lag wave equation is superimposed to establish the aquifer water level model affected by the offshore tide: Where H is the tidal water level elevation of the aquifer; N is the number of tidal wave equations; A i is the amplitude of the ith tidal wave equation; ω i is the angular velocity of the i-th tidal wave equation; is the phase of the ith tidal wave equation; t is the calculation time; m is the average sea level elevation; obtain the tidal type of the pumping test site, and the number of tidal wave equations obtained according to the tidal type is N = 2 to 4 Step S3: Establishing an offshore hydrogeological model affected by tides: Conducting a pumping test, observing the change of groundwater level in the pumping well at any time, and establishing an offshore hydrogeological model affected by tides based on the offshore tidal aquifer water level model (6) and the hydrogeological model (3) of the overflowing confined aquifer: Among them, h is the actual water level elevation in the observation well; H is the tidal water level elevation of the aquifer; s is the water level drawdown in the observation well; t is the pumping time; Q is the flow rate of the pumping well; r is the distance between the observation hole and the pumping well; T is the hydraulic conductivity of the confined aquifer; K is the permeability coefficient of the confined aquifer; m is the thickness of the confined aquifer; B is the overflow factor; u is the well function parameter; N is the number of tidal wave equations; A i is the amplitude of the ith tidal wave equation; ω i is the angular velocity of the i-th tidal wave equation; is the phase of the ith tidal wave equation; m is the mean sea level elevation; Step S4: The offshore hydrogeological model with tidal influence is solved by using the generalized reduced gradient GRG nonlinear solution method to obtain the hydrogeological parameters and tidal disturbance parameters required for the offshore pumping experiment.

2. The method for obtaining tidal hydrogeological parameters based on offshore pumping test according to claim 1, It is characterized in that The operation of determining the tidal type of the pumping test site in step S2 includes the following steps: Collect local tidal observation data or on-site tidal monitoring data, and use discrete Fourier transform to analyze the obtained tidal observation data or on-site tidal monitoring data; According to the analysis results, the tidal type, the number of tidal wave equations, the amplitude range of the tidal wave equations, and the angular velocity range of the tidal wave equations are determined.

3. The method for obtaining tidal hydrogeological parameters based on offshore pumping test according to claim 1, It is characterized in that The objective function established by the generalized reduced gradient GRG nonlinear solution method in step S4 is: Where: h 理论 is the theoretical value of the water level in the observation well calculated according to the offshore hydrogeological model (7) with tidal influence, h 实际 is the actual observed value of the water level in the observation well, N' is the number of observation points used for calculation at different times; σ 2 h is the theoretical value of water level in the observation well calculated according to the offshore hydrogeological model (7) with tidal influence. 理论 The actual observed value of the water level in the observation well h 实际 The variance of .

4. The method for obtaining tidal hydrogeological parameters based on offshore pumping test according to claim 3, It is characterized in that The local optimal solution solution goal set in the generalized reduced gradient GRG nonlinear solution method in step S4 is: the objective function reaches the minimum value and σ 2 is the minimum value.

5. The method for obtaining tidal hydrogeological parameters based on offshore pumping test according to claim 3, It is characterized in that The parameter variable range constraint value used in the generalized reduced gradient GRG nonlinear solution method in step S4 is the result of preliminary analysis using the collected data or monitoring data The initial value used in the generalized reduced gradient GRG nonlinear solution method in step S4 is the starting calculation value.

6. The method for obtaining tidal hydrogeological parameters based on offshore pumping test according to claim 5, It is characterized in that The convergence judgment condition used by the generalized reduced gradient GRG nonlinear solution method in step S4 is: if the calculation result obtained does not converge, change the initial value or boundary value and recalculate.

7. The method for obtaining tidal hydrogeological parameters based on offshore pumping test according to claim 5, It is characterized in that In step S4, if the tide changes with time during the pumping period, the generalized gradient GRG nonlinear solution method is used for piecewise fitting calculation according to the tidal cycle.

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