A fracturing parameter optimization method for improving the reconstruction effect of a tight sandstone reservoir

Abstract

The application discloses a kind of fracturing parameter optimization methods for improving the reconstruction effect of tight sandstone reservoir, the present application includes steps S1-S5, first, the target well to be constructed is selected, the geomechanical parameters of the tight sandstone reservoir in the target well are collected, and the tight sandstone reservoir model in the target well is established, after the tight sandstone reservoir model is established, the perforation parameters and construction parameters are sequentially set in the tight sandstone reservoir model, the numerical simulation of hydraulic fracturing is carried out on the tight sandstone reservoir model in the target well by using three-dimensional discrete lattice method, and finally, the optimal scheme is selected by comparing and analyzing each numerical simulation result, the numerical value of the tight sandstone reservoir hydraulic fracturing in the field is evaluated and obtained by setting the construction parameters of the tight sandstone reservoir model, according to the numerical value of the tight sandstone reservoir hydraulic fracturing in the field evaluated and obtained, the beneficial effects of the present application are that the data of the formation can be mastered and the situation of the construction process can be evaluated before the field construction.

Description

Technical Field

[0001] This invention relates to the field of oil and gas development technology, and in particular to a method for optimizing fracturing parameters to improve the stimulation effect of tight sandstone reservoirs, which is used to optimize fracturing operations for efficient fracturing initiation and uniform propagation of multi-cluster fractures in horizontal wells. Background Technology

[0002] Tight sandstone gas is natural gas distributed within tight sandstone. Sometimes classified as unconventional natural gas, it is found in reservoirs with low porosity, low permeability, low gas saturation, and high water saturation. Natural gas flows slowly within the sandstone layer, and its extraction requires fracturing technology, resulting in high costs.

[0003] In the Qiulin Block of the central Sichuan Basin, the Shaximiao Formation tight sandstone reservoir exhibits poor natural fracture development and strong heterogeneity. During the initial development phase, horizontal well segmented multi-cluster perforation and high-intensity proppant fracturing techniques were employed to stimulate the reservoir's volume. Following on-site fracturing, wide-area electromagnetic monitoring revealed uneven fracture extension between some horizontal well clusters and low perforation initiation efficiency. Therefore, it is crucial to optimize the perforation and construction parameters for this block's tight sandstone reservoir to effectively reduce fracturing pressure, control fracture initiation, improve fracturing efficiency, and promote uniform expansion of multiple fracture clusters, thereby maximizing the reservoir's stimulated volume. Summary of the Invention

[0004] The technical problem to be solved by this invention is that after multi-cluster perforation and high-intensity propagation fracturing operations, tight sandstone reservoirs suffer from uneven fracture propagation between well clusters, low perforation efficiency, and high fracturing pressure after the fractures are fractured. The purpose of this invention is to provide a method for optimizing fracturing parameters to improve the stimulation effect of tight sandstone reservoirs.

[0005] This invention is achieved through the following technical solution:

[0006] A method for optimizing fracturing parameters to improve the stimulation effect of tight sandstone reservoirs includes the following steps:

[0007] S1. Select the target well to be constructed, collect the geomechanical parameters of the tight sandstone reservoir in the target well, and establish a model of the tight sandstone reservoir in the target well. The geomechanical parameters include the model's geometric dimensions, geostress difference, rock elastic modulus, and Poisson's ratio.

[0008] S2. Set the perforation parameters for the tight sandstone reservoir model in the target well. The perforation parameters include the number of holes, hole diameter, phase angle, perforation arrangement, and spacing between multiple perforation clusters.

[0009] S3. Set the construction parameters for the tight sandstone reservoir model in the target well. The construction parameters include pump injection rate, pump injection duration, fracturing fluid viscosity, and fracturing fluid density.

[0010] S4. The three-dimensional discrete lattice method is used to perform a numerical simulation of hydraulic fracturing on the reservoir model in the target well. Based on the geomechanical parameters of the reservoir model in the target well, the numerical simulation results of hydraulic fracturing for each perforation parameter and construction parameter are obtained. The numerical simulation of hydraulic fracturing also includes the formation fracturing pressure value and the geometric morphology of the fracture.

[0011] S5. Compare and analyze the simulation results to select the optimal solution.

[0012] In step S4, the three-dimensional discrete lattice method uses a bonded particle model to simplify rock particles into nodes, and the nodes are connected by springs to represent rock contact surfaces with elastic characteristics. A smooth joint surface model is used to simulate the initial cluster of perforations or pre-existing discontinuous weak surfaces in the rock mass.

[0013] The nodes are connected to springs with normal and shear stiffness. The tension and shear of the springs correspond to the tensile and shear failure of rock particles. A pipe network can be formed between the coin-shaped fluid units located at the center of the fractured spring to allow fluid flow. The quasi-randomly distributed nodes connected by numerous springs form a node-spring network. Joints can be placed in any orientation to accurately and efficiently characterize crack fracture.

[0014] Among them, the three-dimensional discrete lattice method has a mechanical model process. In the mechanical model process of hydraulic fracturing, the relationship between the tensile and shear failure strengths of the spring and the rock is as shown in the following formula (1):

[0015]

[0016] (1) In the formula: With F Smax These represent the breaking tensile force and breaking shear force of the spring, respectively. t The tensile strength correction factor is T, where T and C represent the macroscopic tensile and shear strength of the rock mass, respectively; R represents the mesh element size; μ represents the friction coefficient; and a s This is the shear strength correction factor.

[0017] Among them, the three-dimensional discrete lattice method has a fluid flow model process. In the fluid flow model process of hydraulic fracturing, the pipe width and pipe length are set to be equal. The flow rate formula (2) of water along the pipe from water element A to element B is:

[0018]

[0019] Where, kr =s 2 (3-2s)

[0020] (2) In the formula: q represents fluid flow rate, β is a dimensionless coefficient, and k r P represents relative permeability, a represents crack width, μ represents fluid viscosity, and P represents the fluid viscosity. A and P B ρ represents the water pressure at nodes A and B, respectively. w Let g represent the fluid density, g represent the acceleration due to gravity, and z represent the fluid density. A and z B represents the elevations at nodes A and B respectively, and s represents the water saturation.

[0021] The calculation method was used to solve for q during water flow. i This represents the flow rate q as a function of time, within a flow time step Δt. f The internal flow pressure increment is ΔP, and the formula for calculating ΔP (3) is:

[0022]

[0023] (3) In the formula: The value indicates the elastic modulus of the fluid, and V is the volume of the node. Since the pipe width and pipe length are equal and the flow rate is a constant, V represents the total flow rate of all nodes connected to the water pipe.

[0024] In step S4, the hydraulic fracturing employs a fluid-structure interaction method based on mechanically incompressible fluids. This method injects water into the tight sandstone reservoir, causing stress that fractures the rock and forms fractures or couples between pre-existing joints and rock deformation. The fluid-structure interaction method calculates fracture permeability by considering rock deformation and initial fracture width. Due to the permeability, water pressure acts on the fracture surface, affecting rock deformation. In turn, rock deformation leads to changes in fracture width and water pressure, resulting in changes in fracture permeability.

[0025] The fracturing pressure of the tight sandstone reservoir is obtained directly from the numerical simulation results using the fluid-structure coupling method. The fracture geometry is used to solve the perforation initiation efficiency and the modification volume of each cluster of tight sandstone reservoir fractures.

[0026] The perforation initiation efficiency is calculated using formula (4):

[0027]

[0028] (4) In the formula, Let N be the volume of the i-th fracture cluster, and N be the total number of fracture clusters in a single segment. Let be the fracture volume of the j-th fracture cluster. When the fracture volume of the perforation cluster is greater than the ideal fracture volume (i.e., the total fracture volume divided by the number of fracture clusters is greater than 70%), the perforation cluster is considered an effective perforation cluster.

[0029] The formula (5) for calculating the volume of the fractures in each cluster of tight sandstone reservoirs is as follows:

[0030]

[0031] in,

[0032] (5) In the formula: S V It is the standard deviation of the normalized reservoir stimulation volume. It is the average normalized reservoir stimulation volume of each fracture cluster. It is the reservoir modification volume of the i-th cluster.

[0033] In step S1, the geometric dimensions of the tight sandstone reservoir model are 300m × 80m × 30m.

[0034] In step S1, the geostress difference is obtained by on-site geostress measurement of the tight sandstone reservoir in the target well. The rock elastic modulus and Poisson's ratio of the tight sandstone reservoir are obtained by on-site core sampling and rock mechanics testing. The geomechanical parameters of the tight sandstone reservoir in the target well change depending on the selected target well.

[0035] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0036] 1. In steps S1-S5 of this invention, the target well to be constructed is first selected, the geomechanical parameters of the tight sandstone reservoir in the target well are collected, and a tight sandstone reservoir model in the target well is established. After the tight sandstone reservoir model is established, perforation parameters and construction parameters are set sequentially in the tight sandstone reservoir model. The hydraulic fracturing numerical simulation of the tight sandstone reservoir model in the target well is obtained by using the three-dimensional discrete lattice method. Finally, the results of each numerical simulation are compared and analyzed, and the optimal solution is selected. By setting construction parameters through the establishment of a tight sandstone reservoir model, the numerical values ​​of hydraulic fracturing of the tight sandstone reservoir in the field are evaluated and obtained. Based on the evaluated and obtained numerical values ​​of hydraulic fracturing of the tight sandstone reservoir in the field, the problems of uneven fracture propagation between well clusters, low perforation efficiency, and high fracture pressure after fracturing of the fractures are solved in the field construction of tight sandstone reservoirs.

[0037] 2. This invention focuses on the characteristics of tight gas sandstone reservoirs in different blocks, and studies the perforation initiation law under different Young's modulus, Poisson's ratio, and geostress difference conditions of tight sandstone strata in different blocks.

[0038] 3. This invention focuses on a gas horizontal well in typical tight sandstone as the target well, and studies the perforation scheme. Through numerical simulation, it investigates the influence of different perforation numbers, diameters, phase angles, arrangement methods, and cluster spacing on fracture initiation, deepens the understanding of the fracture initiation law of perforation, and provides guidance for the formulation of perforation parameter optimization schemes for gas horizontal wells in typical tight sandstone of the selected target well.

[0039] 4. This invention conducts field-scale numerical simulations of multi-cluster fracture initiation and propagation in typical tight sandstone gas horizontal wells of selected target wells, and analyzes the reasons for the differences in the stimulation volume and fracturing pressure of tight sandstone reservoirs under different construction parameters (including: pumping flow rate, pumping duration, fracturing fluid viscosity and fracturing fluid density), providing a favorable basis for optimizing hydraulic fracturing construction parameters.

[0040] 5. This invention utilizes the three-dimensional discrete lattice method to establish a model by discretizing the simulated region into point masses and springs connecting the point masses. The computational efficiency is greatly improved compared to the discrete element method, and it can directly simulate the propagation of cracks under true three-dimensional conditions. Attached Figure Description

[0041] The accompanying drawings, which are included to provide a further understanding of the embodiments of the present invention and constitute a part of this application, are not intended to limit the embodiments of the present invention. In the drawings:

[0042] Figure 1 This is a flowchart illustrating the technical process of the present invention.

[0043] Figure 2 This is a diagram of the three-dimensional discrete lattice mechanics and flow model of the present invention;

[0044] Figure 3 This is a schematic diagram of the cluster spacing of a three-dimensional single-segment multi-cluster structure according to the present invention;

[0045] Figure 4 This is a schematic diagram of the spiral perforation of the present invention;

[0046] Figure 5 A schematic diagram of a spiral perforation and a perforation phase angle of 45°;

[0047] Figure 6 A schematic diagram of a spiral perforation and a perforation phase angle of 60°;

[0048] Figure 7 A schematic diagram of a spiral perforation and a perforation phase angle of 45°;

[0049] Figure 8A comparison chart of formation fracturing pressure and reservoir stimulation volume standard deviation under different conditions. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0051] like Figure 1 As shown, the present invention provides a method for optimizing fracturing parameters to improve the stimulation effect of tight sandstone reservoirs, comprising the following steps:

[0052] S1. Select the target well to be constructed, collect the geomechanical parameters of the tight sandstone reservoir in the target well, and establish a model of the tight sandstone reservoir in the target well. The geomechanical parameters include the model's geometric dimensions, geostress difference, rock elastic modulus, and Poisson's ratio.

[0053] S2. Set the perforation parameters for the tight sandstone reservoir model in the target well. The perforation parameters include the number of holes, hole diameter, phase angle, perforation arrangement, and spacing between multiple perforation clusters.

[0054] S3. Set the construction parameters for the tight sandstone reservoir model in the target well. The construction parameters include pump injection rate, pump injection duration, fracturing fluid viscosity, and fracturing fluid density.

[0055] S4. The three-dimensional discrete lattice method is used to perform a numerical simulation of hydraulic fracturing on the tight sandstone reservoir model in the target well. The numerical simulation results of hydraulic fracturing for each perforation parameter and construction parameter are obtained based on the geomechanical parameters of the reservoir model in the target well. The numerical simulation of hydraulic fracturing also includes the formation fracturing pressure value and the geometric morphology of the fracture.

[0056] S5. Compare and analyze the simulation results to select the optimal solution.

[0057] For details, please refer to the following explanation:

[0058] In step S1, a tight sandstone reservoir in the Qiulin block is selected for example analysis. The geometric dimensions of the tight sandstone reservoir model are 300m × 80m × 30m.

[0059] The geostress difference was obtained by on-site geostress measurement of the tight sandstone reservoir in the target well. The rock elastic modulus and Poisson's ratio of the tight sandstone reservoir were obtained by on-site core sampling and rock mechanics testing. The geomechanical parameters of the tight sandstone reservoir in the target well changed depending on the selected target well. In addition, since the selected block of tight sandstone reservoir has strong heterogeneity, the rock mechanics parameters of the tight reservoir in the target well can also be used to simulate the propagation of hydraulic fractures under different rock mechanics parameters by changing them.

[0060] like Figure 2 As shown, the three-dimensional discrete lattice method uses a bonded particle model to simplify rock particles into nodes, and the nodes are connected by springs to represent the rock contact surface with elastic characteristics. A smooth joint surface model is used to simulate the initial cluster of perforations or the pre-existing discontinuous weak surfaces in the rock mass. The nodes are connected to the springs with normal stiffness and shear stiffness. The tension and shear of the springs correspond to the tensile and shear failure of the rock. The coin-shaped fluid units located at the center of the fracture spring can form a pipe network for fluid flow. Numerous spring-connected quasi-randomly distributed nodes form a node-spring network, and joints can be placed in any orientation to accurately and efficiently characterize fractures.

[0061] The three-dimensional discrete lattice method includes: a mechanical model, a fluid flow model, and a fluid-structure interaction process. In the hydraulic model process of hydraulic fracturing, the relationship between the tensile and shear failure strengths of the spring and the rock particles is shown in the following formula (1):

[0062]

[0063] (1) In the formula: With F Smax These represent the breaking tensile force and breaking shear force of the spring, respectively. t The tensile strength correction factor is T, where T and C represent the macroscopic tensile and shear strength of the rock mass, respectively; R represents the mesh element size; μ represents the friction coefficient; and a s This is the shear strength correction factor.

[0064] In the fluid flow model of hydraulic fracturing, the pipe width and length are set to be equal, and the flow rate formula (2) of water along the pipe from water element A to element B is:

[0065]

[0066] Where, k r =s 2 (3-2s)

[0067] (2) In the formula: q represents fluid flow rate, β is a dimensionless coefficient, and k r P represents relative permeability, a represents crack width, μ represents fluid viscosity, and P represents the fluid viscosity.A and P B ρ represents the water pressure at nodes A and B, respectively. w Let g represent the fluid density, g represent the acceleration due to gravity, and z represent the fluid density. A and z B represents the elevations at nodes A and B respectively, and s represents the water saturation.

[0068] The calculation method shown is used to solve for q during water flow. i This represents the flow rate q as a function of time, within a flow time step Δt. f The internal flow pressure increment is ΔP, and the formula for calculating ΔP (3) is:

[0069]

[0070] (3) In the formula: The value indicates the elastic modulus of the fluid, and V is the volume of the node. Since the pipe width and pipe length are equal and the flow rate is a constant, V represents the total flow rate of all nodes connected to the water pipe.

[0071] The fluid-structure interaction (FSI) process described above employs a fluid-structure interaction method proposed by Peter Cundall, which utilizes mechanically incompressible hydraulic fracturing. This method involves injecting water into the tight sandstone reservoir, causing stress that fractures the rock and creates fractures or couples between pre-existing joints and rock deformation. The FSI process uses rock deformation and initial fracture width to determine fracture permeability. Influenced by permeability, water pressure acts on the fracture surface, affecting rock deformation. This deformation, in turn, leads to changes in fracture width and water pressure, ultimately causing variations in fracture permeability. The formation fracturing pressure between rocks can be directly obtained from numerical simulation results. (See [link to relevant documentation]). Figure 8 .

[0072] like Figure 1 As shown, the fracture pressure value of the tight sandstone reservoir is directly obtained from the numerical simulation results using the fluid-solid coupling method. The fracture geometry is used to solve the perforation initiation efficiency and the modification volume of each cluster of tight sandstone reservoir fractures.

[0073] The perforation initiation efficiency is calculated using formula (4):

[0074]

[0075] (4) In the formula, Let N be the crack volume of the i-th crack cluster, and N be the total number of single-segment crack clusters. Let be the fracture volume of the j-th fracture cluster. When the fracture volume of the perforation cluster is greater than the ideal fracture volume (i.e., the total fracture volume divided by the number of fracture clusters is greater than 70%), the perforation cluster is considered an effective perforation cluster.

[0076] The formula (5) for calculating the volume of fractures in each cluster of tight sandstone reservoirs is as follows:

[0077]

[0078] in,

[0079] (5) In the formula: S V It is the standard deviation of the normalized reservoir stimulation volume. It is the average normalized reservoir stimulation volume of each fracture cluster. It is the reservoir modification volume of the i-th cluster.

[0080] The final simulation results are as follows: formation fracturing pressure between rocks, perforation fracturing efficiency, reservoir stimulation volume of each cluster of fractures, and standard deviation of reservoir stimulation volume.

[0081] Finally, it should be noted that, as Figure 3 As shown, there are multiple downhole perforations during the perforation process, and there are single-segment clusters between each perforation. The multiple clusters of single segments form cluster spacing.

[0082] like Figure 4 As shown, the process of spiral perforation S is illustrated. V A schematic diagram of the standard deviation of normalized reservoir stimulation volume and water fracturing pressure. Figure 5-7 This reflects the S-shaped process during spiral perforation from different perspectives. V A schematic diagram of the standard deviation of normalized reservoir stimulation volume and water fracturing pressure.

[0083] This invention collects geological parameters and establishes a model based on the selected target well. Based on the established model, it sets and adjusts perforation and construction parameters to evaluate and determine how to construct the formation and to grasp the formation data.

[0084] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for optimizing fracturing parameters to improve the stimulation effect of tight sandstone reservoirs, characterized in that... It includes the following steps: S1. Select the target well to be constructed, collect the geomechanical parameters of the tight sandstone reservoir in the target well, and establish a model of the tight sandstone reservoir in the target well. The geomechanical parameters include the model's geometric dimensions, geostress difference, rock elastic modulus, and Poisson's ratio. S2. Set the perforation parameters for the tight sandstone reservoir model in the target well. The perforation parameters include the number of holes, hole diameter, phase angle, perforation arrangement, and spacing between multiple perforation clusters. S3. Set the construction parameters for the tight sandstone reservoir model in the target well. The construction parameters include pump injection rate, pump injection duration, fracturing fluid viscosity, and fracturing fluid density. S4. The three-dimensional discrete lattice method is used to perform a numerical simulation of hydraulic fracturing on the tight sandstone reservoir model in the target well. The numerical simulation results of hydraulic fracturing for each perforation parameter and construction parameter are obtained based on the geomechanical parameters of the reservoir model in the target well. The numerical simulation of hydraulic fracturing also includes the formation fracturing pressure value and the geometric morphology of the fracture. S5. Compare and analyze the simulation results to select the optimal solution.

2. The method for optimizing fracturing parameters to improve the stimulation effect of tight sandstone reservoirs according to claim 1, characterized in that, In step S4, the three-dimensional discrete lattice method uses a bonded particle model to simplify rock particles into nodes, and the nodes are connected by springs to represent rock contact surfaces with elastic characteristics. A smooth joint surface model is used to simulate the initial clusters of perforations or pre-existing discontinuous weak surfaces in the rock mass.

3. The method for optimizing fracturing parameters to improve the stimulation effect of tight sandstone reservoirs according to claim 2, characterized in that, The node is connected to the spring, and a network of pipes is formed between the coin-shaped fluid units located at the center of the broken spring to allow fluid flow.

4. The method for optimizing fracturing parameters to improve the stimulation effect of tight sandstone reservoirs according to claim 3, characterized in that, The three-dimensional discrete lattice method has a mechanical model process. In the mechanical model process of hydraulic fracturing, the relationship between the tensile and shear failure strengths of the spring and the rock particles is as shown in the following formula (1): (1) In the formula: F Nmax With F Smax These represent the breaking tensile force and breaking shear force of the spring, respectively. t The tensile strength correction factor is T, where T and C represent the macroscopic tensile and shear strength of the rock mass, respectively; R represents the mesh element size; μ represents the friction coefficient; and a s This is the shear strength correction factor.

5. The method for optimizing fracturing parameters to improve the stimulation effect of tight sandstone reservoirs according to claim 3, characterized in that, The three-dimensional discrete lattice method has a fluid flow model process. In the fluid flow model process of hydraulic fracturing, the pipe width and pipe length are set to be equal. The flow rate formula (2) of water along the pipe from water element A to element B is: Where, k r =s 2 (3-2s) (2) In the formula: q represents fluid flow rate, β is a dimensionless coefficient, and k r P represents relative permeability, a represents crack width, μ represents fluid viscosity, and P represents the fluid viscosity. A and P B ρ represents the water pressure at nodes A and B, respectively. w Let g represent the fluid density, g represent the acceleration due to gravity, and z represent the fluid density. A and z B represents the elevations at nodes A and B respectively, and s represents the water saturation. The calculation method was used to solve for q during water flow. i This represents the flow rate q as a function of time, within a flow time step Δt. f The internal flow pressure increment is ΔP, and the formula for calculating ΔP (3) is: (3) In the formula: The value indicates the elastic modulus of the fluid, and V is the volume of the node. Since the pipe width and pipe length are equal and the flow rate is a constant, V represents the total flow rate of all nodes connected to the water pipe.

6. The method for optimizing fracturing parameters to improve the stimulation effect of tight sandstone reservoirs according to claim 3, characterized in that, The three-dimensional discrete lattice method has a fluid-structure interaction process. The fluid-structure interaction process of hydraulic fracturing uses the fluid-structure interaction method of mechanically incompressible fluids to inject water into the tight sandstone reservoir to generate stress in the rock to fracture the rock and form cracks or to couple pre-existing joints in the rock mass with rock deformation. The fluid-structure interaction solves the fracture permeability by calculating the rock deformation and the initial fracture width. Affected by the permeability, the water pressure acts on the fracture surface and thus affects the rock deformation. The rock deformation, in turn, leads to changes in the fracture width and water pressure, which in turn causes changes in the fracture permeability.

7. The method for optimizing fracturing parameters to improve the stimulation effect of tight sandstone reservoirs according to claim 6, characterized in that, The fracture pressure of the tight sandstone reservoir is obtained directly from the numerical simulation results using the fluid-structure interaction method. The fracture geometry is used to solve the perforation initiation efficiency and the stimulation volume of each cluster of tight sandstone reservoir fractures. The perforation initiation efficiency is calculated using formula (4): (4) In the formula, Let N be the volume of the i-th fracture cluster, and N be the total number of fracture clusters in a single segment. Let be the fracture volume of the j-th fracture cluster. When the fracture volume of the perforation cluster is greater than the ideal fracture volume (i.e., the total fracture volume divided by the number of fracture clusters is greater than 70%), the perforation cluster is considered an effective perforation cluster.

8. The method for optimizing fracturing parameters to improve the stimulation effect of tight sandstone reservoirs according to claim 7, characterized in that, The formula (5) for calculating the volume of fractures in each cluster of tight sandstone reservoirs is as follows: in, (5) In the formula: S V It is the standard deviation of the normalized reservoir stimulation volume. It is the average normalized reservoir stimulation volume of each fracture cluster. It is the reservoir modification volume of the i-th cluster.

9. The method for optimizing fracturing parameters to improve the stimulation effect of tight sandstone reservoirs according to claim 1, characterized in that, In step S1, the geometric dimensions of the tight sandstone reservoir model are 300m × 80m × 30m.

10. The method for optimizing fracturing parameters to improve the stimulation effect of tight sandstone reservoirs according to claim 1, characterized in that, In step S1, the geostress difference is obtained by on-site geostress measurement of the tight sandstone reservoir in the target well. The rock elastic modulus and Poisson's ratio of the tight sandstone reservoir are obtained by on-site core sampling and rock mechanics testing.

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