Land sedimentary basin deep saline water layer gas storage site selection method

Abstract

The invention discloses a land sedimentary basin deep saline water layer gas storage site selection method, which comprises the following steps of: preliminarily delineating a plurality of first candidate areas through judgment of basic geological conditions and hydrogeological conditions; further delineating a second candidate area through reservoir parameter quantitative evaluation, cover layer integrity evaluation, reservoir fracture connectivity evaluation and injection-production process pressure field change dynamic simulation; performing security assessment on the second candidate region; performing economic evaluation on the second candidate region; constructing an index system based on technical, safety and economic indexes, setting the weight of each index, and performing suitability scoring on each second candidate region; selecting the second candidate area with the suitability score meeting the requirement as a gas storage construction preselection point; and the built gas storage in the area adjacent to the gas storage building pre-selection point or the gas storage building pre-selection point verified to be qualified is selected as the gas storage to be put into use. The method can select a suitable site for large-scale safe natural gas storage, and is rapid and efficient to implement and suitable for popularization.

Description

Technical Field

[0001] The invention relates to a site selection method, in particular to a method for site selection of a deep saline water layer gas storage reservoir in a terrestrial sedimentary basin. Background Art

[0002] With the substantial increase in my country's natural gas production, the demand for large-scale gas storage is increasing. At present, underground natural gas storage can be divided into four types: oil and gas reservoir type, underground saline aquifer type, salt cave type, abandoned mine pit and cave type. Among them, underground saline aquifer type is the second largest type of gas storage after oil and gas reservoir type. Saline aquifer gas storage is an artificial gas reservoir formed by injecting natural gas into underground saline aquifers with certain storage conditions under high pressure, and injecting gas to drive water. Saline aquifer gas storage is generally built in aquifers of anticline structure and needs to meet certain basic conditions, such as: good porosity, high permeability and certain thickness; reliable cap layer to ensure that gas will not leak vertically; good sealing around the reservoir to ensure that gas will not leak sideways. Saline aquifer gas storage has the advantage of large reserves and can meet the requirements of large-scale natural gas storage. Therefore, it is urgent to design a technical solution that can be applied to various geological structures and quickly and effectively carry out the site selection of saline aquifer gas storage. Summary of the invention

[0003] The purpose of the present invention is to provide a method for selecting a site for a deep saline layer gas storage reservoir in a terrestrial sedimentary basin, which can select a suitable site for large-scale safe storage of natural gas, is fast and efficient to implement, and is suitable for promotion.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions: A method for selecting a site for a deep saline layer gas storage reservoir in a terrestrial sedimentary basin comprises the following steps: Step 1: Preliminarily identify multiple first candidate areas from the screening area through basic geological conditions and hydrogeological conditions; Step 2: further identify the second candidate area in each first candidate area through quantitative evaluation of reservoir parameters, assessment of cap rock integrity, assessment of reservoir fracture connectivity and dynamic simulation of pressure field changes during injection and production; Step 3: Conduct safety assessment on the second candidate area, including geological hazard assessment, wellbore integrity assessment and leakage simulation assessment; Step 4: Conduct an economic assessment of the second candidate area, including construction cost and operation cost assessment; Step 5: Construct an indicator system based on technical indicators, safety indicators and economic indicators, set the weight of each indicator, and score the suitability of each second candidate area, where: technical indicators include trap closure, reservoir permeability, caprock breakthrough pressure, injection and production capacity, and reservoir capacity; safety indicators include fault activity, seismic risk, and wellbore integrity; economic indicators include distance to ground facilities, single well drilling cost, and transportation pipeline network coverage; Step 6: Select the second candidate area with a suitability score that meets the requirements as the pre-selected site for gas storage construction; Step 7: Check whether there is an existing gas storage in the vicinity of the pre-selected gas storage construction site and make an analogy. If the existing gas storage meets the gas storage requirements, the existing gas storage is selected as the gas storage to be put into use, and the pre-selected gas storage construction site is used as an alternative. Otherwise, conduct on-site tests to verify the pre-selected gas storage construction site, and the qualified pre-selected gas storage construction site is used as the gas storage to be put into use; Step 8: Complete the site selection for the saline gas storage reservoir.

[0005] The advantages of the present invention are: The present invention can quickly and effectively carry out the site selection work of deep saline gas storage in various geological structures of terrestrial sedimentary basins. The method is universal, and the site selection meets the technical, safety and economic requirements. In addition to meeting the demand for large-scale safe natural gas storage, it can also provide technical support for energy transformation and climate change response. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is an implementation flow chart of the method for selecting a site for a deep saline layer gas storage reservoir in a terrestrial sedimentary basin according to the present invention. DETAILED DESCRIPTION

[0007] like Figure 1 The present invention proposes a method for selecting a site for a deep saline layer gas storage reservoir in a terrestrial sedimentary basin, which comprises the following steps: Step 1: Preliminarily identify multiple first candidate areas from the screening area through basic geological conditions and hydrogeological conditions; Step 2: further identify the second candidate area in each first candidate area through quantitative evaluation of reservoir parameters, assessment of cap rock integrity, assessment of reservoir fracture connectivity and dynamic simulation of pressure field changes during injection and production; Step 3: Conduct safety assessment on the second candidate area, including geological hazard assessment, wellbore integrity assessment and leakage simulation assessment; Step 4: Conduct an economic assessment of the second candidate area, including construction cost and operation cost assessment; Step 5: Construct an indicator system based on technical indicators, safety indicators and economic indicators, set the weight of each indicator, and score the suitability of each second candidate area, where: technical indicators include trap closure, reservoir permeability, caprock breakthrough pressure, injection and production capacity, and reservoir capacity; safety indicators include fault activity, seismic risk, and wellbore integrity; economic indicators include distance to ground facilities, single well drilling cost, and transportation pipeline network coverage; Step 6: Select the second candidate area with a suitability score that meets the requirements as the pre-selected site for gas storage construction; Step 7: Check whether there is an existing gas storage in the vicinity of the pre-selected gas storage construction site and make an analogy. If the existing gas storage meets the gas storage requirements, the existing gas storage is selected as the gas storage to be put into use, and the pre-selected gas storage construction site is used as an alternative. Otherwise, conduct an on-site test (small test) to verify the pre-selected gas storage construction site, and the qualified pre-selected gas storage construction site is used as the gas storage to be put into use; Step 8: Complete the site selection for the saline gas storage reservoir.

[0008] Through the above steps, deep saline water layers with superior geological conditions, safety, reliability and economic feasibility can be systematically screened out as gas storage sites in the screening areas where gas storage facilities need to be built. The whole process can be carried out on various geological structures, which is efficient, reliable and suitable for promotion.

[0009] In the present invention, the screening area refers to the area where the site selection of the saline gas storage reservoir is to be carried out, which is aimed at the terrestrial sedimentary basin, is not restricted by the geological structure, and can be an area of ​​the terrestrial sedimentary basin with various geological structures.

[0010] In actual implementation, the basic geological conditions of the first candidate area must meet the requirements of structural stability, burial depth and reservoir thickness, among which: The structural stability requirements must meet the following conditions: It belongs to the weak tectonic activity area with a historical earthquake activity frequency of ≤0.1 times / year; The avoidance distance from active faults is ≥25km, and the avoidance distance from fold belts is ≥1.5km-5km.

[0011] The fold zone avoidance distance of saline gas storage is usually 1.5km–5km, and the specific value can be reasonably determined through geological modeling and dynamic analysis. In actual implementation, the fracture network and long-term sealing of the fold zone need to be evaluated. For example, the China (Ordos) Experimental Saline Reservoir Site Selection Project has a fold zone axis avoidance distance of ≥3km, focusing on the capillary sealing capacity of the caprock.

[0012] The burial depth requirements must meet the following conditions: The reservoir burial depth of the first candidate area is ≥800m to ensure that the formation pressure is ≥15MPa, but the maximum burial depth is ≤3000m (mainly limited by economics in actual implementation); The reservoir thickness requirements must meet the following conditions: The thickness of the single saltwater layer is ≥50m, and the cumulative thickness is ≥200m, and the permeability is ≥0.5mD (preferably between 1mD-10mD).

[0013] In actual implementation, the hydrogeological conditions of the first candidate area must meet the closure requirements and water body energy requirements, including: The closure requirements must meet the following conditions: The hydraulic connection between the saline water layer in the first candidate area and its adjacent saline water layer can be analyzed through the regional hydrogeological map to avoid the connection problem between the constructed gas storage reservoir and the domestic water layer (such as the Quaternary loose layer) and the industrial water source layer.

[0014] The water energy requirements must meet the following conditions: Based on the estimation of the groundwater runoff direction and flow rate in the first candidate area, the permeability of the saline layer in the first candidate area is made to differ from that of its adjacent areas by 2 orders of magnitude or more (a permeability difference of 2 orders of magnitude or more means that the ratio between the two is 100 times or more) to ensure that there is no risk of saltwater intrusion during the injection and production process of the constructed gas storage.

[0015] Furthermore, in actual implementation, the estimation of groundwater runoff direction and velocity includes the following steps: Through pressure tests of existing wells (such as DST and RFT), multiple hydraulic head values ​​h at different well locations are obtained, and an isohydraulic line diagram is drawn based on the hydraulic head values. In the isohydraulic line diagram, the vertical isohydraulic line from the high potential area to the low potential area is the runoff direction; For two wells, the hydraulic gradient i is calculated by calculating the ratio of the head difference Δh between the two wells and the horizontal distance L between the two wells, that is, i=Δh / L. Then, according to Darcy's law, that is, v=K×i / φ, the actual groundwater flow velocity v is estimated, where: K is the permeability, obtained by laboratory measurement or well test analysis (such as pressure drop test), φ is the effective porosity, which is used to exclude the influence of dead pores; Establish a groundwater flow model (such as MODFLOW, FEFLOW), input boundary conditions (recharge area, discharge area), reservoir parameters and head data, compare the estimated actual groundwater flow rate with the field observation value, find the estimated actual groundwater flow rate with an error of <5% as the final groundwater flow rate, and use the runoff direction corresponding to the two wells involved in estimating the actual groundwater flow rate (that is, the runoff direction closest to the line connecting the two wells) as the final groundwater runoff direction.

[0016] In actual implementation, the quantitative evaluation of reservoir parameters includes the quantitative evaluation of reservoir physical parameters and trap types, including: The reservoir physical property parameters of the second candidate area must meet the following conditions: The porosity obtained through core analysis or logging interpretation is between 10%-25%, the permeability is between 0.5mD-50mD, and the gas saturation is ≥60%; The trap type of the second candidate area must meet the following conditions: If it is an anticline structure or a fault-sealed structure, the trap volume is ≥ 10 km 3 , among which the closure degree of the anticline structure is ≥50m.

[0017] In practice, the reservoir capacity can be estimated through quantitative evaluation of reservoir parameters.

[0018] In the site selection of saline gas storage, the assessment of cap rock integrity and reservoir fracture connectivity is directly related to the reservoir's sealing, gas injection capacity and long-term stability.

[0019] In practical implementation, caprock integrity assessment includes an evaluation of the lithologic combination, including: The lithology combination of the second candidate area must meet the following conditions: If the cap rock is shale or mudstone, the breakthrough pressure shall be ≥10MPa, and the thickness of the mudstone shall be ≥50m.

[0020] Specifically, the evaluation of lithologic combinations includes the following steps: A. Identify lithology through the curves obtained from logging and complete stratification; B. Evaluate the closure of the lithology combination and obtain the trap closure degree; C. Construct a lithofacies model based on steps A and B (e.g., using Petrel software), predict the spatial distribution of reservoir-caprock, and complete the lithology combination assessment.

[0021] In step A, conventional logging or imaging logging can be used for logging. In conventional logging, the obtained natural gamma (GR), acoustic time difference (AC), density (DEN), neutron porosity (CNL) and other curves can be used to distinguish sandstone (reservoir), mudstone (caprock), salt rock, etc. In imaging logging (FMI / UBI), curves that intuitively display the lithology interface and fracture distribution can be obtained. The core obtained by logging is observed to determine the rock type, grain size, cement (such as calcareous, siliceous), and the mineral composition (such as quartz, clay content) is quantified by X-ray diffraction (XRD) and thin section analysis, thereby completing the stratification operation.

[0022] In step B, the evaluation of the sealing property of the lithology combination is obtained through the cap rock breakthrough pressure test or the gas-water displacement experiment, wherein: the breakthrough pressure of mudstone / salt rock is determined by the laboratory cap rock breakthrough pressure test, requiring the cap rock breakthrough pressure to be greater than the reservoir gas injection pressure; the capillary sealing capacity of the cap rock is evaluated by the capillary pressure curve obtained by the gas-water displacement experiment (such as the threshold pressure ≥ 5MPa).

[0023] In actual implementation, the reservoir fracture connectivity of the second candidate area must meet the following conditions: The fracture density identified by seismic attribute analysis (such as AVO inversion) is ≤ 3 fractures / km 2 , and the extension direction of the crack is obtained at the same time.

[0024] Specifically, the assessment of reservoir fracture connectivity includes the following steps: Step a: Qualitatively identify fractures through imaging logging (FMI / MSFL) or core observation, including: identifying fracture types (tension fractures, shear fractures), occurrence (dip, strike) and filling conditions (open fractures / calcareous filling) through imaging logging (FMI / MSFL); directly calculating fracture density (bars / meter), aperture and connectivity by observing cores, and distinguishing natural fractures from drilling-induced fractures.

[0025] Step b: Quantitatively characterize the fractures through well logging interpretation model or seismic attribute analysis, where: Based on the logging interpretation model, the cross-plot of acoustic wave (AC), resistivity (RT) and porosity (φ) is used to identify the fracture development section, and the fracture porosity φ is calculated by the acoustic wave time difference method. f , and the permeability K is calculated by the cubic law f , see the following formula:

[0026] Among them, d is the fracture aperture, C is the empirical coefficient, △t is the measured acoustic wave time difference, which represents the time difference of acoustic wave propagation in the formation, △t ma is the acoustic time difference of bedrock (no pores, no cracks), △t f The time difference of sound waves that fill the fracture with fluid (usually water or mud).

[0027] Seismic attribute analysis includes prediction of fracture density zones through well-known techniques such as curvature, coherence volume, and ant volume tracking.

[0028] Step c: Perform dynamic testing to verify fracture connectivity through well test analysis or tracer testing, where: Well test analysis is to determine the contribution of fractures to permeability (dual porosity model) through pressure transient tests (such as pressure drop / recovery tests), that is, to verify fracture connectivity.

[0029] Tracer testing is to monitor the breakthrough time by injecting tracers to verify fracture connectivity; Step d: Establish a discrete fracture network (DFN) model (such as FracMan software) to simulate the migration path of gas along the fractures to intuitively display the fracture connectivity.

[0030] In actual implementation, the dynamic simulation of pressure field changes during the injection and production process includes: establishing a three-dimensional geological model for the first candidate area, simulating the dynamic changes of the pressure field during the injection and production process, and estimating the area where the gas-water interface movement rate is ≤0.5m / year through the dynamic changes of the pressure field as the second candidate area.

[0031] In the site selection of saline gas storage, the dynamic simulation of pressure field changes during the injection and production process is a key link in evaluating the reservoir closure, gas migration law and long-term stability. Based on the dynamic simulation of pressure field changes during the injection and production process, the injection and production capacity of the reservoir can be evaluated, as well as the storage capacity.

[0032] The dynamic simulation of pressure field changes during injection and production specifically includes the following steps: Step 1) Determine the model input parameters and select the model, where: The model input parameters include reservoir parameters, heterogeneity distribution parameters (such as permeability anisotropy, interlayer), fluid property parameters, salt water density (ρ_w), viscosity (μ_w) and dissolved gas content. Reservoir parameters include porosity (φ), permeability (K), reservoir thickness (h) and initial pressure (P 0 ), fluid property parameters include gas composition (CH 4 , CO 2 etc.), viscosity (μg) and compressibility factor (Z).

[0033] In actual implementation, boundary conditions are set by reservoir geometry (closed / open), initial pressure gradient and groundwater flow velocity.

[0034] According to the simulation object (such as single gas, mixed gas), select an appropriate model from the black oil model, component model and coupling model, where: Black oil models (such as Eclipse and CMG) are suitable for single gases (such as CH 4 )injection and production simulation; Component models (such as GEM, TOUGH2) are suitable for mixed gases (such as CH 4 +CO 2 ) or chemical reaction scenarios; Coupled models are suitable for integrating fluid flow and geomechanics (such as ABAQUS+Eclipse) to analyze stress changes.

[0035] Step 2) simulation, including the steps: 2-1) Search for corresponding historical test injection data according to the model input parameters, and input the historical test injection data to calibrate the model; 2-2) The injection and production process is simulated in stages, including the gas injection stage and the gas production stage, where: During the gas injection stage, set the gas injection rate (e.g. 100×104m 3 / d), simulate the pressure field diffusion and gas saturation distribution, and monitor the reservoir pressure changes to ensure that the fracture pressure (Pfrac=0.7×minimum principal stress) is not exceeded; During the gas production phase, the pressure drop rate is simulated to evaluate the gas recovery rate and water intrusion risk.

[0036] Step 3) Evaluate areas where the air-water interface migration rate is ≤ 0.5 m / year.

[0037] When conducting a safety assessment of the second candidate area, the geological hazard assessment includes an assessment of fault activity and ground subsidence risk, among which: the fault activity assessment is to verify whether the activity rate of the fault zone is ≤0.01mm / year in order to avoid active fault zones; the ground subsidence risk assessment is to use InSAR monitoring data to estimate whether the historical subsidence rate is ≤2mm / year.

[0038] Wellbore integrity assessment includes counting the number of abandoned wells, plugging abandoned wells, and verifying whether the plugging depth of abandoned wells is ≥ 50m above the top of the aquifer, and whether the cement bonding rating is ≥ Grade A. Here, the cement bonding rating can be based on China's "Design Code for Underground Gas Storage" (GB / T 50459-2017) and "Oil and Gas Field Abandoned Well Disposal Code" (SY / T 6646-2018).

[0039] The leakage simulation assessment includes the use of multiphase flow simulation to obtain the migration path of the saltwater layer interface and estimate whether the leakage probability is <1×10 -6 / Year.

[0040] In actual implementation, the possibility of inducing earthquakes can be assessed through the above-mentioned geological disaster assessment and / or leakage simulation assessment, that is, an earthquake risk assessment can be made.

[0041] When conducting an economic assessment of the second candidate area, the construction cost assessment includes the cost of drilling a single well (sandstone layer drilling cost ≤ RMB 8 million / well) and the cost of the surface gathering and transportation system (≥ RMB 100 million).

[0042] The operating cost assessment estimates the cost from the compression energy consumption (≤0.3kWh / m³) and the injection-production cycle (≥30 years), involving the distance to the ground facilities and the coverage of the transportation pipeline network.

[0043] In addition, a public acceptance survey should be conducted on the second candidate area and a determination should be made as to whether there is any land use conflict.

[0044] For step 5, in the site selection of saline gas storage, it is very important to determine the weights of technical indicators, safety indicators, and economic indicators. They are usually obtained by comprehensive methods such as the analytic hierarchy process (AHP), expert scoring method (Delphi), and entropy weight method (objective weighting). The entropy weight method is applicable to scenarios where there is a large amount of actual data (such as parameters of multiple candidate reservoirs). The weight is calculated by the degree of data dispersion. Its characteristic is that the greater the data fluctuation of the indicator (such as significant differences in reservoir thickness), the higher the weight.

[0045] In the present invention, the suitability score can be divided into three levels: ≥85 points for priority development areas, 70-84 points for secondary priority development areas, and <70 points for elimination and abandonment areas.

[0046] In actual implementation, the technical indicators, safety indicators and economic indicators can be appropriately adjusted according to the actual geological conditions and gas storage construction requirements, and the weight of each indicator can be appropriately adjusted to re-evaluate the suitability of each second candidate area. For example, the weight of the safety indicator can be increased to 30%.

[0047] In step 7, the field test verification of the pre-selected points for gas storage construction includes injection and production cycle test and long-term sealing test, among which: The injection-production cycle test is to ensure that the gas injection volume of a single well is ≥ 100,000 m 3 / d, pressure gradient ≤ 0.01MPa / m, monitoring the stability of the gas-water interface in the drilling well; The long-term tightness test is to monitor the tightness of the saltwater layer for 6 months to determine whether the pressure fluctuation is <5%.

[0048] For example, a gas storage site is selected in a certain area of ​​the Junggar Basin. First, the basic geological conditions and hydrogeological conditions of the area are determined, and the first candidate area is delineated. Then, the reservoir parameters are quantitatively evaluated, the cap rock integrity is evaluated, the reservoir fracture connectivity is evaluated, and the pressure field change dynamic simulation during the injection and production process is performed in the first candidate area, and then the second candidate area is delineated. The second candidate area is finally delineated as the Jurassic Badaowan Formation sandstone layer with a burial depth of 1200m-1800m in the central area, and the gas-water interface movement rate is ≤0.3m / year, which meets the requirements. In the process of delineating the second candidate area, technical indicators such as trap closure, reservoir permeability, cap rock breakthrough pressure, injection and production capacity, and storage capacity are obtained. Then a safety assessment is conducted to obtain safety indicators such as fault activity, seismic risk, and wellbore integrity, and an economic assessment is conducted to obtain economic indicators such as ground facility distance, single well drilling cost, and transportation pipeline coverage. According to the actual situation and needs, the weight of technical indicators is set to 60%, including: closure degree of trap accounts for 15%, reservoir permeability accounts for 12%, caprock breakthrough pressure accounts for 10%, injection and production capacity accounts for 10%, and storage capacity accounts for 13%. The weight of safety indicators is set to 25%, including: fault activity accounts for 10%, earthquake risk accounts for 8%, and wellbore integrity accounts for 7%. The weight of economic indicators is set to 15%, including: ground facility distance (priority within 10km), single well drilling cost (≤8 million yuan), and transportation pipeline coverage rate (≥80%) each account for 5%. Therefore, the technical indicator score is 88, the safety indicator score is 82, the economic indicator score is 75, and the total suitability score is 81.5, which belongs to the secondary priority development area. Because there is no gas storage built in the adjacent area, a field test (small test) is carried out for verification. After the injection and production cycle test and long-term sealing test, it is verified to be qualified, so this area is used as a gas storage to be put into use. Thus, the site selection of saline gas storage is completed.

[0049] The present invention can quickly and effectively carry out the site selection work of deep saline gas storage in various geological structures of terrestrial sedimentary basins. The method is universal, and the site selection meets the technical, safety and economic requirements. In addition to meeting the demand for large-scale safe natural gas storage, it can also provide technical support for energy transformation and climate change response.

[0050] The technologies not described in detail in the present invention are well-known or familiar technologies in the industry and will not be described in detail in the present invention.

[0051] The above are preferred embodiments of the present invention and the technical principles used therein. For those skilled in the art, any obvious changes such as equivalent transformations, simple replacements, etc. based on the technical solution of the present invention, without departing from the spirit and scope of the present invention, are within the scope of protection of the present invention.

Claims

1. A method for selecting a site for a deep saline gas storage reservoir in a terrestrial sedimentary basin, characterized in that: Includes steps: Step 1: Preliminarily identify multiple first candidate areas from the screening area through basic geological conditions and hydrogeological conditions; Step 2: further identify the second candidate area in each first candidate area through quantitative evaluation of reservoir parameters, assessment of cap rock integrity, assessment of reservoir fracture connectivity and dynamic simulation of pressure field changes during injection and production; Step 3: Conduct safety assessment on the second candidate area, including geological hazard assessment, wellbore integrity assessment and leakage simulation assessment; Step 4: Conduct an economic assessment of the second candidate area, including construction cost and operation cost assessment; Step 5: Construct an indicator system based on technical indicators, safety indicators and economic indicators, set the weight of each indicator, and score the suitability of each second candidate area, where: technical indicators include trap closure, reservoir permeability, caprock breakthrough pressure, injection and production capacity, and reservoir capacity; safety indicators include fault activity, seismic risk, and wellbore integrity; economic indicators include distance to ground facilities, single well drilling cost, and transportation pipeline network coverage; Step 6: Select the second candidate area with a suitability score that meets the requirements as the pre-selected site for gas storage construction; Step 7: Check whether there is an existing gas storage in the vicinity of the pre-selected gas storage construction site and make an analogy. If the existing gas storage meets the gas storage requirements, the existing gas storage is selected as the gas storage to be put into use, and the pre-selected gas storage construction site is used as an alternative. Otherwise, conduct on-site tests to verify the pre-selected gas storage construction site, and the qualified pre-selected gas storage construction site is used as the gas storage to be put into use; Step 8: Complete the site selection for the saline gas storage reservoir.

2. The method for selecting a site for a deep saline gas storage reservoir in a terrestrial sedimentary basin according to claim 1, characterized in that: The basic geological conditions of the first candidate area meet the requirements of structural stability, burial depth and reservoir thickness, among which: The structural stability requirements shall meet the following conditions: It belongs to the weak tectonic activity area with a historical earthquake activity frequency of ≤0.1 times / year; The avoidance distance from active faults is ≥25km, and the avoidance distance from fold belts is ≥1.5km-5km; The burial depth requirements must meet the following conditions: The reservoir burial depth of the first candidate area is ≥800m, but the maximum burial depth is ≤3000m; The reservoir thickness is required to meet the following conditions: The thickness of a single saltwater layer is ≥50m, the cumulative thickness is ≥200m, and the permeability is ≥0.5mD.

3. The method for selecting a site for a deep saline layer gas storage reservoir in a terrestrial sedimentary basin according to claim 1, characterized in that: The hydrogeological conditions of the first candidate area meet the closure requirements and water body energy requirements, wherein: The closure requirements must meet the following conditions: Analyze the hydraulic connection between the saline water layer where the first candidate area is located and its adjacent saline water layer through the found regional hydrogeological map; The water body energy requirements meet the following conditions: Based on the estimation of the groundwater runoff direction and flow velocity of the first candidate area, the permeability of the saline water layer where the first candidate area is located differs from the permeability of its adjacent areas by 2 orders of magnitude or more.

4. The method for selecting a site for a deep saline layer gas storage reservoir in a terrestrial sedimentary basin according to claim 3, characterized in that: The estimation of groundwater runoff direction and velocity comprises the steps of: Through the pressure test of existing wells, multiple hydraulic head values ​​at different well locations are obtained, and an isohydraulic line diagram is drawn based on the hydraulic head values. In the isohydraulic line diagram, the vertical isohydraulic line from the high potential area to the low potential area is the runoff direction; For two wells, the hydraulic gradient is obtained by calculating the ratio of the hydraulic head difference between the two wells to the horizontal distance between the two wells, and then the actual groundwater flow rate is estimated according to Darcy's law; A groundwater flow model was established, and the estimated actual groundwater flow velocity was compared with the field observation value. The estimated actual groundwater flow velocity with an error of <5% was found as the final groundwater flow velocity, and the runoff direction corresponding to the two wells involved in estimating the actual groundwater flow velocity was taken as the final groundwater runoff direction.

5. The method for selecting a site for a deep saline layer gas storage reservoir in a terrestrial sedimentary basin according to claim 1, characterized in that: The quantitative evaluation of reservoir parameters includes quantitative evaluation of reservoir physical parameters and trap types, wherein: The reservoir physical property parameters of the second candidate area meet the following conditions: The porosity obtained through core analysis or logging interpretation is between 10%-25%, the permeability is between 0.5mD-50mD, and the gas saturation is ≥60%; The closure type of the second candidate area meets the following conditions: If it is an anticline structure or a fault-closed structure, the closed volume shall be ≥10km³, among which the closure degree of the anticline structure shall be ≥50m.

6. The method for selecting a site for a deep saline layer gas storage reservoir in a terrestrial sedimentary basin according to claim 1, characterized in that: The caprock integrity assessment includes an assessment of the lithology combination, including: The lithology combination of the second candidate area meets the following conditions: if the cap rock is shale or mudstone, the breakthrough pressure is ≥10MPa, where the thickness of the mudstone is ≥50m; The evaluation of the lithology combination comprises the steps of: A. Identify lithology through the curves obtained from logging and complete stratification; B. Evaluate the closure of the lithology combination and obtain the trap closure degree; C. Based on steps A and B, a lithofacies model is constructed to predict the spatial distribution of reservoir-caprock and complete the lithology combination assessment.

7. The method for selecting a site for a deep saline gas storage reservoir in a terrestrial sedimentary basin according to claim 1, characterized in that: The reservoir fracture connectivity of the second candidate area meets the following conditions: the fracture density identified by seismic attribute analysis is ≤ 3 fractures / km², and the extension direction of the fractures is obtained at the same time, where: The evaluation of reservoir fracture connectivity comprises the steps of: Step a: Qualitative identification of fractures through imaging logging or core observation; Step b: quantitatively characterize the fractures through well logging interpretation model or seismic attribute analysis; Step c: Verify fracture connectivity by dynamic testing through well test analysis or tracer testing; Step d: Establish a discrete fracture network model to simulate the migration path of gas along the fractures to intuitively display the fracture connectivity.

8. The method for selecting a site for a deep saline layer gas storage reservoir in a terrestrial sedimentary basin according to claim 1, characterized in that: The dynamic simulation of pressure field changes during the injection and production process includes: establishing a three-dimensional geological model for the first candidate area, simulating the dynamic changes of the pressure field during the injection and production process, and estimating the area where the gas-water interface movement rate is ≤0.5m / year through the dynamic changes of the pressure field as the second candidate area.

9. The method for selecting a site for a deep saline layer gas storage reservoir in a terrestrial sedimentary basin according to claim 1, characterized in that: When conducting a safety assessment on the second candidate area, the geological disaster assessment includes an assessment of fault activity and ground subsidence risk, wherein: the fault activity assessment is to verify whether the activity rate of the fault zone is ≤0.01mm / year, so as to avoid the active fault zone; the ground subsidence risk assessment is to estimate whether the historical subsidence rate is ≤2mm / year using InSAR monitoring data; The wellbore integrity assessment includes counting the number of abandoned wells, plugging the abandoned wells, and verifying whether the plugging depth of the abandoned wells is ≥ 50m from the top of the aquifer, and whether the cement bonding rating is ≥ Grade A; The leakage simulation assessment includes using multiphase flow simulation to obtain the migration path of the saltwater layer interface and estimating whether the leakage probability is <1×10 -6 / Year.

10. The method for selecting a site for a deep saline layer gas storage reservoir in a terrestrial sedimentary basin according to claim 1, characterized in that: When conducting an economic evaluation of the second candidate area, the construction cost evaluation includes the cost of drilling a single well and the cost of the surface gathering and transportation system; The operating cost assessment estimates the cost from the compression energy consumption and the injection-production cycle, involving the distance to the ground facilities and the coverage of the transportation pipeline network.

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