Integrated simulation method for fracturing transformation and yield prediction of low-permeability reservoir horizontal well

Abstract

The invention discloses a low-permeability reservoir horizontal well fracturing transformation and yield prediction integrated simulation method, system and device and a medium, and relates to the technical field of reservoir yield increase transformation. The method comprises the steps that a low-permeability reservoir geologic model is built according to field geology and drilling data; a low-permeability reservoir horizontal well fracturing fracture-forming and proppant transportation coupling model is constructed; combining a horizontal well fracturing simulation result and an indoor flow conductivity experiment result to predict the global flow conductivity of the hydraulic fracture; constructing a low-permeability reservoir horizontal well production oil-water two-phase seepage model, and predicting reservoir oil-water distribution characteristics and horizontal well yield after low-permeability reservoir fracturing; and according to a prediction result, evaluating a low-permeability reservoir horizontal well fracturing transformation result, and optimizing horizontal well fracturing construction parameters. By means of the method, integrated simulation of low-permeability reservoir horizontal well fracturing fracture forming, proppant migration and after-fracturing yield prediction can be achieved, the fracturing transformation effect is evaluated according to the horizontal well yield prediction result, fracturing construction parameters are optimized, and the low-permeability reservoir horizontal well fracturing transformation effect is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of reservoir stimulation and reconstruction, and particularly relates to a low-permeability reservoir horizontal well fracturing reconstruction and production prediction integrated simulation method, system, device and medium. BACKGROUND

[0002] With the growing demand for oil and gas resource exploration and development worldwide, the importance of unconventional oil and gas resources is gradually highlighted, and a low-cost and high-efficiency development method becomes the key to commercial exploitation of low-grade resources. At present, the process system combining horizontal wells and hydraulic fracturing is still the preferred solution for the profitable exploitation of low-permeability reservoirs. By increasing the contact area between the wellbore and the reservoir through a long horizontal section, the permeability and flowability of the reservoir fluid are improved by using an artificial fracture network, the controlled reserves of a single well are enhanced, and the overall producing degree of the reservoir resources is improved. Under the existing technical framework, how to optimize the fracturing parameters and improve the reservoir reconstruction effect becomes a key concern in the development of low-permeability reservoirs.

[0003] The post-fracturing dynamic production characteristics of a low-permeability reservoir mainly depend on the spatial distribution of hydraulic fractures and the placement results of proppants in the fractures. There is a significant coupling effect between the hydraulic fracture propagation and the proppant migration, and the interaction results determine the geometry and conductivity of the hydraulic fractures, which further affect the reservoir oil-water distribution characteristics during the production process of the low-permeability reservoir. Therefore, coupling the key processes of low-permeability reservoir reconstruction and production, such as hydraulic fracture propagation, proppant migration and oil-water two-phase seepage, is the key to guiding field production and development. Due to the invisibility of the underground environment and the field scale characteristics, at present, engineers and scholars mainly use numerical simulation to study and explore the above processes. However, most of the researches are only focused on the single process of fracturing, sand placement and production, and the fracturing effect evaluation methods mainly use the parameters such as the geometry of the hydraulic fracture, the placement characteristics of the proppant and the reservoir reconstruction volume as the evaluation indexes. In the production prediction aspect, the uniform placement of the proppant in the fracture is assumed, and important influencing factors such as the coupling effect of the hydraulic fracture propagation and the proppant migration, the non-uniform distribution of the hydraulic fracture conductivity and the post-fracturing oil-water two-phase seepage characteristics are not fully considered. It is difficult to directly reflect the quantitative influence law of different fracturing parameters on the production performance, and there is a lack of an integrated simulation method for fracturing reconstruction and production prediction, which can optimize the key parameters of the low-permeability reservoir fracturing reconstruction by taking the production as the evaluation index. SUMMARY

[0004] The present application aims to provide a low-permeability reservoir horizontal well fracturing reconstruction and production prediction integrated simulation method, system, device and medium, which realizes the integrated simulation of the fracturing, proppant migration and post-fracturing production prediction of the low-permeability reservoir horizontal well, evaluates the fracturing reconstruction effect and optimizes the fracturing construction parameters according to the horizontal well production prediction results, and improves the fracturing reconstruction effect of the low-permeability reservoir horizontal well.

[0005] This invention is achieved through the following technical solution: In a first aspect, the first embodiment of the present invention provides an integrated simulation method for horizontal well fracturing and production prediction in low-permeability reservoirs, comprising the following steps: S1: Construct a geological model of a low-permeability reservoir based on field geological and drilling data; S2: Construct a coupled model of horizontal well fracturing and proppant transport in low-permeability reservoirs, predict the characteristics of hydraulic fractures and proppant placement, and obtain the simulation results of horizontal well fracturing. S3: Combining horizontal well fracturing simulation results with indoor conductivity experiments, predict the overall conductivity of hydraulic fractures; S4: Construct a two-phase flow model for oil and water production in horizontal wells of low-permeability reservoirs, and combine the full-domain conductivity of hydraulic fractures to predict the oil and water distribution characteristics of the post-compression reservoir and the production of horizontal wells in low-permeability reservoirs, and obtain the prediction results. S5: Evaluate the fracturing results of horizontal wells in low-permeability reservoirs based on the prediction results, and optimize the fracturing construction parameters of horizontal wells.

[0006] Furthermore, specific methods for constructing geological models of low-permeability reservoirs based on field geological and drilling data include: S11: Collect geological, drilling and production data of the target block, establish a three-dimensional structural model and sedimentary facies model, and obtain porosity and permeability property models; S12: Obtain basic reservoir parameters in the horizontal well segmented fracturing stimulation area. These parameters include: maximum horizontal principal stress, minimum horizontal principal stress, vertical stress, interlayer stress difference, stress gradient, reservoir thickness, pore pressure, Young's modulus, and Poisson's ratio.

[0007] Furthermore, specific methods for constructing a coupled model of horizontal well fracturing and proppant transport in low-permeability reservoirs include: S21: Constructing a mathematical model for hydraulic fracture deformation: Based on the displacement discontinuity method, the hydraulic fractures at the mine scale are discretized into rectangular fracture elements. A hydraulic fracture deformation model is established according to the stress-deformation relationship. An induced stress calculation model is established to describe the stress interference between hydraulic fractures during segmented multi-cluster fracturing of horizontal wells. S22: Establish a mathematical model for fracturing fluid flow, including: using Poiseuille's law to describe the fracturing fluid flow in hydraulic fractures, using porous media seepage theory to describe the fracturing fluid seepage process in the reservoir, calculating the fracturing fluid loss based on the fluid pressure relationship between the hydraulic fracture and the reservoir matrix, considering the flow rate differences of different perforation clusters during the segmented multi-cluster fracturing process in horizontal wells, establishing a set of fluid pressure equations using Kirchhoff's law, and solving them using Newton's iteration method to obtain the dynamic flow rate distribution results of each perforation cluster in the segmented multi-cluster fracturing of horizontal wells at different times; S23: Establish a hydraulic fracture propagation model, including: using the equivalent stress intensity criterion as the basis for judging hydraulic fracture propagation; when the equivalent stress intensity factor of the fracture tip element is greater than or equal to the fracture toughness of the rock, the hydraulic fracture propagates; and new fracture elements are added to the current hydraulic fracture tip; the propagation direction of the hydraulic fracture is predicted based on the maximum circumferential stress criterion; and the deflection angle of the hydraulic fracture tip element is calculated. S24: Construct a proppant transport model within hydraulic fractures, including: calculating the density and viscosity of the mixed proppant and fracturing fluid, using a clogging function to describe the proppant's permeability in hydraulic fractures, calculating the corrected proppant settling velocity, and establishing a mathematical model for proppant transport in hydraulic fractures based on Euler's multiphase flow theory. S25: Solve the coupling model of horizontal well fracturing and proppant transport in low-permeability reservoirs, including: based on the hydraulic fracture deformation model and the fracturing fluid flow model, establish a set of control equations for hydraulic fracture and fracturing fluid seepage in the reservoir matrix, a set of control equations for proppant migration in the hydraulic fracture, and a set of fluid-structure coupling equations for hydraulic fracture propagation in the horizontal well segmented multi-cluster fracturing. Iterate the hydraulic fracture width, fluid pressure inside the fracture, proppant concentration inside the fracture, and pore pressure of the reservoir matrix under the same time step using a sequential coupling method.

[0008] Furthermore, specific methods for constructing a two-phase flow model for oil-water production in horizontal wells of low-permeability reservoirs include: S31: After the horizontal well fracturing simulation is completed, the proppant thickness is calculated based on the hydraulic fracture width and the proppant concentration in the fracture, and the hydraulic fracture unit is divided into filled unit and unfilled unit according to the filling thickness. S32: The conductivity of proppant-filled and unpadded hydraulic fracture elements was obtained through indoor experiments; S33: Calculate the closure stress based on the geostress and hydraulic fracture-induced stress of the target low-permeability reservoir, and perform interpolation based on the conductivity chart to obtain the spatial distribution of conductivity of filled and unfilled fracture units.

[0009] Furthermore, specific methods for constructing a two-phase flow model for oil-water production in horizontal wells of low-permeability reservoirs include: S41: Establish a mathematical model for two-phase flow of oil and water in the matrix of low-permeability oil reservoirs; S42: Establish a mathematical model for two-phase oil-water flow in hydraulic fractures of low-permeability reservoirs; S43: Establish a mathematical model for calculating production after hydraulic fracturing in low-permeability reservoirs; S44: Based on the embedded discrete fracture theory, the flow conduction relationship between the reservoir matrix and hydraulic fractures is established. The mathematical model of two-phase flow in the reservoir matrix and hydraulic fractures is numerically discretized using the finite volume method. A mathematical model of two-phase flow of matrix-fracture-wellbore oil-water under constant pressure production conditions in horizontal wells of low-permeability reservoirs is established.

[0010] Furthermore, specific methods for predicting the oil-water distribution characteristics of post-compression reservoirs and the production of horizontal wells in low-permeability oil reservoirs by combining the overall conductivity of hydraulic fractures include: S45: Design key construction parameters for horizontal well fracturing stimulation of reservoirs based on the development needs of low-permeability reservoirs; S46: Simulate horizontal well fracturing and proppant transport in low-permeability reservoirs to obtain hydraulic fracture trajectory, fracture size and proppant placement results; S47: Based on the prediction results of hydraulic fracture geometry parameters and proppant concentration distribution, calculate the overall conductivity of the hydraulic fracture after horizontal well fracturing. S48: Using the full-domain conductivity of hydraulic fractures as input, dynamic simulation of production after horizontal well pressure in low-permeability reservoirs is carried out based on the mathematical model of matrix-fracture-wellbore oil-water two-phase flow. S49: Output the reservoir oil-water distribution and horizontal well production results corresponding to different horizontal well fracturing and stimulation construction schemes.

[0011] Furthermore, based on the prediction results, the specific methods for evaluating the fracturing results of horizontal wells in low-permeability reservoirs and optimizing the fracturing parameters of horizontal wells include: Based on the prediction results, the cumulative production of horizontal wells under the same production conditions is used as the metric to evaluate the stimulation effect of different horizontal well fracturing construction schemes and optimize the key construction parameters for horizontal well fracturing stimulation in low-permeability reservoirs.

[0012] Secondly, another embodiment of the present invention provides an integrated simulation system for horizontal well fracturing and production prediction in low-permeability reservoirs, used to implement the integrated simulation method for horizontal well fracturing and production prediction in low-permeability reservoirs described in the first embodiment above, including: a first model construction module, a second model construction module, a prediction module, a third model construction module, and a calculation and optimization module; The first model building module is used to build a geological model of a low-permeability oil reservoir based on field geology and drilling data; The second model building module is used to construct a coupled model of horizontal well fracturing and proppant transport in low-permeability reservoirs, predict the characteristics of hydraulic fractures and proppant placement, and obtain the simulation results of horizontal well fracturing. The prediction module is used to combine the results of horizontal well fracturing simulation with the results of indoor conductivity experiments to predict the overall conductivity of hydraulic fractures. The third model is used to construct a two-phase flow model for oil and water production in horizontal wells of low-permeability reservoirs. It combines the full-domain conductivity of hydraulic fractures to predict the oil and water distribution characteristics of the post-compression reservoir and the production of horizontal wells in low-permeability reservoirs, and obtains the prediction results. The calculation and optimization module is used to evaluate the fracturing results of horizontal wells in low-permeability reservoirs based on the prediction results and to optimize the fracturing construction parameters of horizontal wells.

[0013] Thirdly, another embodiment of the present invention provides an electronic device comprising: a processor, an input device, an output device, and a memory, wherein the processor, the input device, the output device, and the memory are interconnected, the memory is used to store a computer program, the computer program including program instructions, wherein the processor is configured to invoke the program instructions to execute the method described in the first embodiment above.

[0014] Fourthly, another embodiment of the present invention provides a computer-readable storage medium storing a computer program, the computer program including program instructions that, when executed by a processor, cause the processor to perform the method described in the first embodiment above.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects: This invention provides an integrated simulation method, system, equipment, and medium for horizontal well fracturing and production prediction in low-permeability reservoirs, which has the following advantages: (1) By proppant stacking and bridging and changes in the rheological parameters of the mixed sand, the dynamic coupling simulation of hydraulic fracturing fracture propagation and proppant transport is realized, and the hydraulic fracture morphology and proppant placement results are accurately predicted. (2) Obtain the hydraulic fracture conductivity chart under proppant-filled and unfilled conditions through indoor experiments, and reasonably calculate the full-domain conductivity of the hydraulic fracture after pressure by combining the hydraulic fracture geometric parameters and proppant concentration simulation results. (3) Combining the full-domain conductivity of hydraulic fractures with the matrix-fracture-wellbore oil-water two-phase flow model, we can realize the integrated simulation of horizontal well fracturing and production prediction. Based on the production prediction results of horizontal wells, we can evaluate the fracturing effect and optimize the fracturing construction parameters to improve the fracturing effect of horizontal wells in low-permeability reservoirs and help low-permeability reservoirs reduce costs, increase efficiency and improve quality development. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 A flowchart illustrating an integrated simulation method for horizontal well fracturing and production prediction in low-permeability reservoirs, provided in the first embodiment of the present invention; Figure 2 A schematic diagram of the porosity model for a target low-permeability oil reservoir; Figure 3 Schematic diagram of a permeability model for a target low-permeability oil reservoir; Figure 4 Schematic diagram of simulation results of hydraulic fracture propagation trajectory and geometric morphology under different schemes; Figure 5 Schematic diagram of simulated proppant concentration distribution within hydraulic fractures under different scenarios; Figure 6 A schematic diagram of the flow capacity of proppant-filled cracks for indoor experiments; Figure 7 A schematic diagram of the conductivity of unsupported cracks obtained for indoor experiments; Figure 8 A schematic diagram showing the calculation results of the overall hydraulic fracture conductivity under different schemes; Figure 9 This is a schematic diagram of the relative permeability curves of the aqueous and oil phases in the reservoir matrix. Figure 10 This is a schematic diagram of the relative permeability curves of the water phase and the oil phase in a hydraulic fracture. Figure 11 This is a schematic diagram of the capillary pressure curves of the aqueous and oil phases in the reservoir matrix. Figure 12 Schematic diagram of reservoir pore pressure prediction results for horizontal well production under different schemes; Figure 13 Schematic diagram showing the prediction results of water saturation of production reservoirs in horizontal wells under different schemes; Figure 14 A schematic diagram of the cumulative production curves of horizontal wells under different schemes; Figure 15 The diagram below shows a structural block diagram of an integrated simulation system for fracturing and production prediction of horizontal wells in low-permeability reservoirs, provided as another embodiment of the present invention. Detailed Implementation

[0017] 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.

[0018] like Figure 1 As shown, the first embodiment of the present invention proposes an integrated simulation method for horizontal well fracturing and production prediction in low-permeability reservoirs, which mainly includes the following steps: S1: Construct a geological model of a low-permeability reservoir based on field geological and drilling data; S2: Construct a coupled model of horizontal well fracturing and proppant transport in low-permeability reservoirs, predict the characteristics of hydraulic fractures and proppant placement, and obtain the simulation results of horizontal well fracturing. S3: Combining the horizontal well fracturing simulation results with the laboratory conductivity test results, predict the overall conductivity of the hydraulic fracture; S4: Construct a two-phase flow model of oil and water production in a horizontal well in a low-permeability reservoir, and combine the overall conductivity of the hydraulic fracture to predict the oil-water distribution characteristics of the reservoir after fracturing and the production of the horizontal well, and obtain the prediction results. S5: Evaluate the fracturing results of horizontal wells in low-permeability reservoirs based on the prediction results, and optimize the fracturing construction parameters of horizontal wells.

[0019] Specifically, step S1: Constructing a geological model of a low-permeability reservoir based on on-site geological and drilling data includes: S11: Collect geological, drilling and production data of the target block, establish a three-dimensional structural model and sedimentary facies model, and obtain property models such as porosity and permeability; S12: Obtain the horizontal well segmented fracturing stimulation area and obtain parameters such as the maximum horizontal principal stress, minimum horizontal principal stress, vertical stress, interlayer stress difference, stress gradient, reservoir thickness, pore pressure, Young's modulus, and Poisson's ratio of the reservoir.

[0020] In this embodiment, by collecting and processing geological, drilling, and production data of the target low-permeability reservoir, and through three-dimensional structural and sedimentary facies modeling, a porosity and permeability attribute model is obtained, referring to... Figure 2 and Figure 3 Further, based on the reservoir rock mechanical properties and oil-water distribution characteristics, horizontal well segmented fracturing stimulation zones were selected, and basic reservoir parameters of the zones to be stimulated were obtained, as shown in Table 1.

[0021] Table 1. Basic reservoir parameters in the horizontal well staged fracturing stimulation zone of the example.

[0022] Specifically, methods for constructing a coupled model of horizontal well fracturing and proppant transport in low-permeability reservoirs include: S21: Construct a mathematical model for hydraulic fracture deformation, specifically including: Based on the displacement discontinuity method, hydraulic fractures at the mine scale are discretized into rectangular fracture elements, and a hydraulic fracture deformation model is established according to the stress-deformation relationship: ; Establish an induced stress calculation model to describe the stress interference between hydraulic fractures during multi-cluster fracturing in horizontal wells: ; Where the subscripts L, H, and N represent the direction, dip, and normal direction along the hydraulic fracture, respectively; D L D H τ represents the tangential displacement of the crack element along the strike and dip directions, respectively; w represents the normal displacement of the crack element, i.e., the crack width; L τ H σ N These represent the stresses acting on the rectangular crack element along its direction, tangential direction, and normal direction, respectively; A inf This represents the stress boundary influence coefficient matrix, which characterizes the stress influence generated by the displacement of a crack element at a certain point in space.

[0023] S22: Establish a mathematical model for fracturing fluid flow, specifically including: Poiseuille's law is used to describe the flow of fracturing fluid in hydraulic fractures: ; The fracturing fluid seepage process in the reservoir is described using Darcy's seepage theory for porous media: ; Calculation of fracturing fluid loss based on the fluid pressure relationship between hydraulic fractures and reservoir matrix: ; in, t Indicates time; μ f Indicates the viscosity of the fracturing fluid; p f This indicates the fluid pressure within the hydraulic fracture; p m Indicates reservoir pore fluid pressure; γ represents the hydrostatic pressure gradient of the fluid; z represents the unit vector along the direction of gravity; q f,inj Indicates the fracturing fluid injection source term; q m,inj The fracturing fluid injection source term in the reservoir is described and obtained through fracturing fluid loss calculation. q leak Indicates the fracturing fluid loss item; ψ p Indicates the volume fraction of proppant within the hydraulic fracture; Indicates reservoir matrix porosity; k m The reservoir matrix permeability is represented by C, calculated from the fracturing fluid filtration loss. leak This represents the fluid flow coefficient between the hydraulic fracture and the reservoir matrix, which can be obtained through theoretical derivation or laboratory experiments.

[0024] Considering the flow rate differences of different perforation clusters during multi-cluster fracturing in a horizontal well, a set of fluid pressure equations is established using Kirchhoff's law and solved using Newton's iterative method to obtain the dynamic flow rate distribution results of each perforation cluster during multi-cluster fracturing in a horizontal well at different times.

[0025] S23: Establish a hydraulic fracture propagation model, specifically including: The equivalent stress intensity criterion is used as the basis for judging the propagation of hydraulic fractures. When the equivalent stress intensity factor of the fracture tip element is greater than or equal to the fracture toughness of the rock, the hydraulic fracture propagates and a new fracture element is added to the current hydraulic fracture tip. ; Among them, K e K represents the equivalent stress intensity factor of a hydraulic fracture tip element. IC K represents the fracture toughness of reservoir rocks. I K represents the tensile stress intensity factor. II Indicates the shear stress intensity factor. θ This indicates the deflection angle for the propagation of a hydraulic fracture.

[0026] Based on the maximum circumferential stress criterion for predicting the propagation direction of hydraulic fractures, the formula for calculating the deflection angle of the hydraulic fracture tip element is as follows:

[0027] S24: Construct a proppant transport model within hydraulic fractures, specifically including: Based on Euler's multiphase flow theory, a mathematical model for proppant transport in hydraulic fractures is established: .

[0028] Wherein, ψp represents the volume concentration of the proppant; ρ represents the dimensionless proppant concentration. f Indicates the density of fracturing fluid; μ s Indicates the viscosity of the mixing solution; v p Indicates the proppant transport rate; v s Indicates the flow velocity of the mixing fluid; v set Indicates the settling velocity of the proppant; This indicates the dimensionless proppant injection concentration.

[0029] The formulas for calculating the density and viscosity of the proppant-fracturing fluid mixture are as follows: .

[0030] Where, ψ p,max Indicates the maximum permissible proppant concentration; ρ s ρ represents the density of the proppant-fracturing fluid mixture.p Indicates the density of the proppant; μ f This indicates the viscosity of the fracturing fluid.

[0031] The proppant permeability in hydraulic fractures is described using a clogging function: ; The corrected proppant settling velocity is: ; Among them, v stokes N represents the Stokes settling velocity of the particles. min With N max Indicates the bridging coefficient; d p Indicates the proppant particle size; C com This represents the comprehensive correction coefficient for particle settling, characterizing the combined influence of factors such as particle inertia, particle concentration, and wall roughness on particle settling. It can be obtained from laboratory experiments or empirical formulas.

[0032] S25: Solution of the coupled model of horizontal well fracturing and proppant transport, specifically including: Based on the hydraulic fracture deformation model and the fracturing fluid flow model, a set of fluid-structure interaction equations for the propagation of multi-cluster fracturing fractures in horizontal wells is established: ; Among them, M M Represents the hydraulic fracture deformation coefficient matrix; C f The matrix represents the flow coefficient of fracturing fluid in a hydraulic fracture; w represents the fracture width matrix; p f p represents the fluid pressure matrix in a hydraulic fracture. m σ represents the pore pressure matrix in the reservoir matrix; M q represents the stress matrix under far-field stress. f,s This represents the fracturing fluid source term matrix in a hydraulic fracture.

[0033] The governing equations for fracturing fluid seepage in the reservoir matrix are as follows: ; in, This represents the fracturing fluid permeability coefficient matrix in the reservoir matrix; Matrix of fracturing fluid source terms in reservoir matrix.

[0034] The governing equations for proppant migration in hydraulic fractures are: ; in, This represents the proppant transport coefficient matrix. q represents the dimensionless concentration matrix of proppant in hydraulic fractures; p,s This represents the proppant source term matrix.

[0035] The Newton-Raphson iterative method is used to solve the fluid-structure interaction nonlinear equations. The increments of the hydraulic fracture width and the fluid pressure within the fracture in the current iteration step are: , , .

[0036] Where I represents the identity matrix; F1 and F2 are the Newton-Raphson iteration coefficient matrices.

[0037] The stability of the solution is enhanced by Picard iteration. The updated hydraulic fracture width and fluid pressure within the fracture in the current iteration step are: ; For fracturing fluid seepage in the reservoir matrix, after calculating the fluid pressure in the hydraulic fractures, the fracturing fluid source term in the reservoir matrix is ​​obtained through the fracturing fluid filtration relationship. Then, the reservoir pore pressure distribution is solved explicitly by discretization using the finite volume method. ; The fluid pressure in the hydraulic fracture was calculated, as were the flow velocities of the mixed sand and proppant. Then, the finite volume method was used to discretize and solve the governing equations for proppant migration in the hydraulic fracture. An upwind scheme was used to discretize the convection terms to mitigate numerical oscillations and achieve a stable numerical solution. ; ; ; ; .

[0038] After arranging the control equations for proppant migration, the calculated proppant concentration distribution in the hydraulic fracture is shown: ; In the above formula, Indicates the time step. , These represent the length and width of the rectangular crack element, respectively.

[0039] The control equations for fracturing fluid seepage in the hydraulic fracture and reservoir matrix, the control equations for proppant migration in the hydraulic fracture, and the fluid-structure interaction equations for hydraulic fracture propagation are performed iteratively in a sequential coupling manner at the same time step. After calculation, the hydraulic fracture width, fluid pressure within the fracture, proppant concentration within the fracture, and pore pressure of the reservoir matrix can be obtained. The convergence condition is: ; in, , This represents the convergence tolerance of the slit width and the fluid pressure within the slit.

[0040] In this embodiment, the number of perforation clusters is used as the construction optimization target to conduct a coupled simulation of horizontal well fracturing and proppant transport in low-permeability reservoirs. Considering refined fracturing construction design, a single horizontal section is used as the reservoir stimulation object, and the simulation design scheme is shown in Table 2. Without changing the fracturing section length, this embodiment simulates four schemes: 3 clusters, 4 clusters, 5 clusters, and 6 clusters, and the simulation basic parameters are shown in Table 3. A stepped proppant transport scheme is adopted. The pumping procedure in this embodiment is shown in Table 4. The pumping procedure remains consistent under different scheme conditions, including stages such as pre-fracturing with pre-fluid, proppant transport with proppant-carrying fluid, and pump shutdown. Based on the coupled model of horizontal well fracturing and proppant transport in low-permeability reservoirs constructed in step S2, the hydraulic fracture extension trajectory and geometric morphology after pump shutdown are shown in Table 4. Figure 4 As shown, due to the interference of inter-slit stress and the distribution of proppant, the hydraulic fractures located in the middle perforation cluster have smaller fracture lengths and widths, and exhibit a staggered extension characteristic in space. Figure 5 This represents the dimensionless concentration distribution of proppant in the hydraulic fractures at the moment of pump shutdown. Due to the combined effects of inter-fracture interference and proppant transport, the fracture width exhibits a non-uniform distribution in space. Proppant tends to accumulate in areas with extremely narrow fracture widths at the leading edge of the hydraulic fracture, resulting in higher proppant concentrations in these areas. Conversely, proppant concentrations are lower in areas with wider fractures, and no proppant is placed in some areas with extremely narrow fracture widths that do not meet the passage criteria. Because inter-fracture interference and proppant transport differ under different perforation cluster numbers, the hydraulic fracture morphology and proppant placement characteristics differ significantly after the simulation results for the four schemes. In the following steps, this embodiment will evaluate the modification effects of different schemes through production prediction and optimize the perforation cluster number.

[0041] Table 2 Simulation Design Scheme of Examples

[0042] Table 3. Basic parameters for the simulation of the coupling of horizontal well fracturing and proppant transport in the examples.

[0043] Table 4. Simulation Pumping Procedure for Coupled Horizontal Well Fracturing and Propion Transport in Examples

[0044] Specifically, step S3: Combining the horizontal well fracturing simulation results with the indoor conductivity experiment results, predict the overall conductivity of the hydraulic fracture, including: S31: After the horizontal well fracturing simulation is completed, the proppant thickness is calculated based on the hydraulic fracture width and the proppant concentration within the fracture. The hydraulic fracture unit is then divided into filled and unfilled units based on the thickness of the fill. ; in, Indicates the thickness of the proppant filling; Indicates the width of the hydraulic crack; This indicates the volume concentration of the proppant.

[0045] S32: Obtain the conductivity of proppant-filled and unpadded hydraulic fracture elements through indoor experiments. Specific steps include: First, based on the indoor diversion capacity test conditions, a rock plate with the same geometric dimensions as the diversion chamber was made using a rock sample similar to the target reservoir. Hydraulic fractures are prefabricated by artificially splitting rock slabs. Closed rock slabs without proppant are considered as unfilled hydraulic fractures, while those with proppant are considered as filled hydraulic fractures. Next, indoor flow diversion experiments were conducted. For unfilled hydraulic cracks, the change in flow diversion capacity under different closure stresses was measured. For filled hydraulic cracks, the change in flow diversion capacity and laying thickness under different filling thicknesses and closure stresses was measured. Finally, using indoor flow capacity experimental data, flow capacity charts of proppant-filled and unpadded hydraulic fractures were plotted, and the mathematical relationship between the thickness of the proppant-filled layer and the closure stress was obtained.

[0046] S33: Calculate the closure stress based on the geostress and hydraulic fracture-induced stress of the target low-permeability reservoir, and perform interpolation based on the conductivity chart to obtain the spatial distribution of conductivity of filled and unfilled fracture units.

[0047] In this embodiment, crack elements with a filling thickness of less than 0.1 mm are considered as unfilled elements. Figure 4 and Figure 5 The spatial distribution of hydraulic fracture width and proppant concentration within the fracture is used to obtain the distribution of filled and unfilled units within the hydraulic fracture. Based on the proppant parameters used in the simulation in step S2, the conductivity of propped-filled and unfilled hydraulic fracture units is obtained through laboratory experiments. The conductivity of propped-filled fractures is referenced... Figure 6 The conductivity of the unfilled cracks is referenced. Figure 7 The closure stress of hydraulic fractures is calculated using the target reservoir in-situ stress parameters and the distribution of induced stress between fractures. Interpolation is then performed based on conductivity charts to obtain the conductivity distribution of the hydraulic fractures. The conductivity distribution results under different scenarios are obtained, and reference is made to... Figure 8 .

[0048] Specifically, step S4: Constructing a two-phase flow model for oil-water production in a horizontal well of a low-permeability reservoir, including: S41: Establish a mathematical model for the two-phase flow of oil and water in the matrix of low-permeability oil reservoirs, specifically including: Establish the continuity equation for the oil and water phases in porous media: ; in, and These represent the densities of the aqueous phase and the oil phase, respectively; and the densities of the aqueous phase and the oil phase, respectively. and These represent the saturation levels of the aqueous and oil phases in the matrix, respectively. and These represent the seepage velocities of the aqueous and oil phases in the matrix, respectively. and These represent the source terms of the aqueous and oil phases in the matrix, respectively. Indicates reservoir matrix porosity.

[0049] Based on Darcy's law, the momentum equations for the oil and water phases in porous media are established: .

[0050] in, k rwm and k rom These represent the relative permeabilities of the aqueous and oil phases in the matrix, respectively, and can be obtained through indoor experiments. μ w and μ o These represent the viscosity of the aqueous phase and the viscosity of the oil phase, respectively. p wm and p om These represent the fluid pressures of the aqueous and oil phases in the matrix, respectively.

[0051] The mathematical model for the change in matrix permeability caused by the decrease in reservoir pore pressure during the production process of low-permeability oil reservoirs is as follows: ; The coupling conditions for the flow of water and oil phases in the reservoir matrix are as follows: .

[0052] In the above formula, k em Indicates the effective permeability of the reservoir matrix; k m,0 Indicates the initial permeability of the reservoir matrix; t Indicates time; p mi and pm Indicates the initial and current pore pressure of the reservoir; C m Indicates the reservoir matrix stress sensitivity coefficient; p c This represents the capillary pressure in the reservoir matrix.

[0053] S42: Establish a mathematical model for two-phase oil-water flow in hydraulic fractures of low-permeability reservoirs, specifically including: Establish the continuity equation for the oil and water phases in hydraulic fractures: ; in, S wf and S of These represent the saturation levels of the water and oil phases in the fracture, respectively. v wf and v of These represent the seepage velocities of the water phase and the oil phase in the fracture, respectively. and These represent the source terms of the aqueous and oil phases in the fracture, respectively. This indicates the porosity of the crack.

[0054] Momentum equations for oil and water phases in hydraulic fractures: ; in, k rwf and k rof The relative permeabilities of the water phase and oil phase in the fracture are represented by , respectively, and a linear weighted approximation of the saturation of the water phase and oil phase in the fracture is adopted. k ef Indicates the effective permeability of the crack; k f,0 This indicates the initial permeability of the crack.

[0055] The mathematical model for the change in fracture permeability caused by the decrease in pressure within hydraulic fractures during the production process of low-permeability oil reservoirs is as follows: ; The coupling conditions for water and oil phase flow in hydraulic fractures are as follows: ; in, p fi and p f C represents the initial and current fluid pressures in the hydraulic fracture. f This represents the stress sensitivity coefficient of the crack.

[0056] S43: Establish a mathematical model for calculating production after hydraulic fracturing in low-permeability reservoirs, specifically including: Establish a mathematical model for the transmission relationship between the horizontal wellbore and the hydraulic fracture element: ; Establish a mathematical model for hydraulic fracture source terms: ; In the above formula, Γ fw This represents the conductivity coefficient between the hydraulic fracture and the horizontal wellbore. w f Indicates the width of the hydraulic fracture element; r e The equivalent wellbore radius is determined by the geometry of the hydraulic fracture element. r w Represents the horizontal wellbore radius; p w This indicates the pressure at the bottom of the well.

[0057] S44: Combining reservoir matrix, hydraulic fractures, horizontal wellbore, and other flow modules, this paper establishes the flow conduction relationship between the reservoir matrix and hydraulic fractures based on embedded discrete fracture theory. It uses the finite volume method to numerically discretize the two-phase flow mathematical model in the reservoir matrix and hydraulic fractures, establishing an integrated oil-water two-phase flow mathematical model of matrix-fracture-wellbore under constant pressure production conditions in low-permeability horizontal wells. ; The solution is obtained using the Newton-Raphson iterative method, with the stability of the solution increased or decreased using the Picard iterative method. The convergence condition is as follows: ; In the above formula, C represents the oil-water two-phase flow coefficient matrix; the subscripts m and f represent the reservoir matrix and hydraulic fracture, respectively, and different combinations of the two represent the coupling relationship between the reservoir matrix and the hydraulic fracture; p m With p f Represent the reservoir matrix pore pressure matrix and the hydraulic fracture fluid pressure matrix, respectively; q m With q f represents the reservoir matrix source term matrix and the hydraulic fracture source term matrix, respectively; n represents the iteration step.

[0058] In this embodiment, based on the full-domain conductivity of the hydraulic fractures obtained in step S4, and combined with the two-phase flow model of oil-water production in the horizontal well, further simulation of post-fracturing horizontal well production in low-permeability reservoirs is conducted. Under the condition of sufficient flowback after horizontal well fracturing, the reservoir matrix water saturation is approximately equal to the initial water saturation. The relative permeability curves of the water phase and oil phase can be obtained by fitting indoor experimental data, referring to... Figure 9The permeability and porosity in hydraulic fractures are much greater than those in the reservoir matrix. A linear weighted method based on water saturation was used to obtain the relative permeability curves of the water and oil phases in the hydraulic fractures. Considering the capillary force between the water and oil phases in the reservoir matrix, capillary force data at different water saturations were obtained through laboratory experiments. (See attached...) Figure 11 The remaining basic parameters for conducting production simulations of horizontal wells after pressure in low-permeability reservoirs are shown in Table 5.

[0059] Using a constant pressure production system, under the same production pressure differential and production time conditions, the production forecast results for Schemes 1, 2, 3, and 4 are as follows: Figure 12 and Figure 13 As shown. Figure 12 This refers to the reservoir pore pressure distribution after horizontal well production in low-permeability reservoirs under different schemes. The production of crude oil and formation water in the reservoir will cause a significant decrease in pore pressure around hydraulic fractures. Due to differences in the hydraulic fracture trajectory and spatial conductivity distribution under different schemes, the pore pressure distribution after horizontal well production also varies significantly. Similarly, Figure 13 These are the pore pressure distribution characteristics after production simulations under different schemes, and the simulation results of different schemes also show significant differences.

[0060] Table 5. Basic parameters for simulation of oil-water two-phase flow model in horizontal wells of low-permeability reservoirs in the examples.

[0061] Specifically, step S4, which combines the overall conductivity of hydraulic fractures to predict the oil-water distribution characteristics of low-permeability reservoirs after compression and the production of horizontal wells, includes: S45: Design key construction parameters for horizontal well fracturing stimulation of reservoirs based on the development needs of low-permeability reservoirs; S46: Simulate horizontal well fracturing and proppant transport in low-permeability reservoirs to obtain hydraulic fracture trajectory, fracture size, and proppant placement results; S47: Based on the prediction results of hydraulic fracture geometry parameters and proppant concentration distribution, calculate the overall conductivity of the hydraulic fracture after horizontal well fracturing. S48: Using the full-domain conductivity of hydraulic fractures as input, dynamic simulation of production after horizontal well pressure in low-permeability reservoirs is carried out based on the mathematical model of matrix-fracture-wellbore oil-water two-phase flow. S49: Output the reservoir oil-water distribution and horizontal well production results corresponding to different horizontal well fracturing and stimulation construction schemes.

[0062] In this embodiment, the number of perforation clusters is used as the construction optimization target for simulation and optimization. Key construction parameters for horizontal well fracturing stimulation of the reservoir are referred to in Tables 2 and 3. Hydraulic fracture trajectory, fracture size, and proppant placement results are obtained based on a coupled model of horizontal well fracturing and proppant transport. The simulation results are referenced... Figure 4and Figure 5 Furthermore, combining indoor experimental and numerical simulation results, the overall hydraulic fracture conductivity after horizontal well fracturing was calculated. The results are referenced... Figure 8 Subsequently, using the overall conductivity of the hydraulic fracture as input, and combining it with a mathematical model of the two-phase flow of oil and water in a horizontal well in a low-permeability reservoir, production dynamics were predicted. The reservoir oil-water distribution and horizontal well production results corresponding to different scenarios were obtained, and referenced... Figure 12 , Figure 13 as well as Figure 14 .

[0063] Specifically, step S5: Evaluate the fracturing results of horizontal wells in low-permeability reservoirs based on the prediction results, and optimize the horizontal well fracturing operation parameters, including: Based on the prediction results, the cumulative production of horizontal wells under the same production conditions is used as the evaluation index to assess the stimulation effect of different horizontal well fracturing construction schemes, and then optimize the key construction parameters for horizontal well fracturing stimulation in low-permeability reservoirs.

[0064] In this embodiment, by conducting coupled simulations of horizontal well fracturing and proppant transport, calculating the full-domain hydraulic fracture conductivity after fracturing, and simulating and predicting production dynamics after horizontal well fracturing, the production dynamics corresponding to different construction schemes were obtained. Figure 14 . Figure 4 The simulation results show that from Scheme 1 to Scheme 4, as the number of perforation clusters increases, the spacing between hydraulic fracture clusters gradually decreases, and the interference between fractures gradually intensifies, which prevents the fractures located in the middle cluster from extending sufficiently. At the same time, it affects the distribution of proppant and the conductivity of hydraulic fractures after fracturing. Figure 5 The proppant concentration distribution results indicate that inter-fracture interference causes differences in the fracturing fluid and proppant dosage entering hydraulic fractures from different perforation clusters. Simultaneously, the uneven distribution of fracture width results in some hydraulic fracture areas lacking proppant filling. Combined with... Figure 4 , Figure 5 , Figure 8 It is known that the geometric parameters of hydraulic fractures, the spatial distribution of proppant concentration, and the conductivity of hydraulic fractures all differ under different schemes. Conventional metrics such as hydraulic fracture length, hydraulic fracture area, proppant placement area, and hydraulic fracture conductivity are insufficient to reasonably judge the effectiveness of different construction schemes and thus improve the development of low-permeability reservoirs. This invention integrates horizontal well fracturing stimulation with production prediction simulation, focusing on the production rate, which is of great engineering concern, and evaluates the merits of different hydraulic fracturing construction schemes based on production results. Figure 14 The production dynamics prediction results for horizontal wells under different construction schemes show that, under the same production regime and production time conditions, the cumulative oil production does not exhibit a monotonically increasing trend with the increase of the number of perforation clusters; Scheme 3 has the highest cumulative production. Therefore, under the conditions of this embodiment, the optimized parameters are 5 perforation clusters and a cluster spacing of 15m.

[0065] The present invention provides an integrated simulation method for horizontal well fracturing and production prediction in low-permeability reservoirs, which has the following advantages compared with the prior art: (1) The embodiments of the present invention realize the dynamic coupling simulation of hydraulic fracturing fracture propagation and proppant transport by proppant stacking and bridging and the change of rheological parameters of the mixed sand, and accurately predict the hydraulic fracture morphology and proppant placement results; (2) The embodiments of the present invention obtain the hydraulic fracture conductivity chart under proppant filling and non-push-filling conditions through indoor experiments, and reasonably calculate the full-domain conductivity of the hydraulic fracture after pressure by combining the hydraulic fracture geometric parameters and proppant concentration simulation results; (3) The embodiments of the present invention combine the full-domain conductivity of hydraulic fractures with the matrix-fracture-wellbore oil-water two-phase flow model to realize the integrated simulation of horizontal well fracturing and production prediction. The fracturing effect is evaluated and the fracturing construction parameters are optimized based on the horizontal well production prediction results, thereby improving the fracturing effect of horizontal wells in low-permeability reservoirs and helping to reduce costs, increase efficiency and improve the quality of development of low-permeability reservoirs.

[0066] like Figure 15 As shown, another embodiment of the present invention provides an integrated simulation system for horizontal well fracturing and production prediction in low-permeability reservoirs, used to implement the integrated simulation method for horizontal well fracturing and production prediction in low-permeability reservoirs described in the above embodiments. The system includes: a first model construction module, a second model construction module, a prediction module, a third model construction module, and a calculation and optimization module. The first model building module is used to build a geological model of a low-permeability oil reservoir based on field geology and drilling data. The second model building module is used to construct a coupled model of horizontal well fracturing and proppant transport in low-permeability reservoirs, predict the characteristics of hydraulic fractures and proppant placement, and obtain the simulation results of horizontal well fracturing. The prediction module is used to combine the results of horizontal well fracturing simulation with the results of indoor conductivity experiments to predict the overall conductivity of hydraulic fractures. The third model is used to construct a two-phase flow model for oil and water production in horizontal wells of low-permeability reservoirs. It combines the global conductivity of hydraulic fractures to predict the oil and water distribution characteristics of the post-compression reservoir and the production of horizontal wells in low-permeability reservoirs, and obtains the prediction results. The calculation and optimization module is used to evaluate the fracturing results of horizontal wells in low-permeability reservoirs based on the prediction results and to optimize the fracturing construction parameters of horizontal wells.

[0067] The execution process of each module of the system can be carried out in accordance with the process steps of the integrated simulation method for horizontal well fracturing and production prediction in low-permeability reservoirs described in the first embodiment, and will not be repeated in this embodiment.

[0068] Another embodiment of the present invention provides an electronic device, which includes a processor, an input device, an output device, and a memory. The processor, input device, output device, and memory are interconnected. The memory is used to store a computer program, which includes program instructions. The processor is configured to call the program instructions to execute the integrated simulation method for fracturing and production prediction of horizontal wells in low-permeability reservoirs described in the first embodiment above.

[0069] It should be understood that, in the embodiments of the present invention, the processor may be a Central Processing Unit (CPU), but it may also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0070] Input devices may include touchpads, fingerprint sensors (used to collect the user's fingerprint information and fingerprint orientation information), microphones, etc., while output devices may include displays (LCDs, etc.), speakers, etc.

[0071] The memory may include read-only memory and random access memory, and provides instructions and data to the processor. A portion of the memory may also include non-volatile random access memory. For example, the memory may also store information about the device type.

[0072] In specific implementations, the processor, input device, and output device described in the embodiments of the present invention can execute the implementation of the method embodiments described in the embodiments of the present invention, or they can execute the implementation of the system embodiments described in the embodiments of the present invention, which will not be repeated here.

[0073] The present invention also provides an embodiment of a computer-readable storage medium storing a computer program, the computer program including program instructions, which, when executed by a processor, cause the processor to perform the integrated simulation method for fracturing and production prediction of horizontal wells in low-permeability reservoirs described in the first embodiment above.

[0074] The computer-readable storage medium can be an internal storage unit of the terminal described in the foregoing embodiments, such as the terminal's hard drive or memory. The computer-readable storage medium can also be an external storage device of the terminal, such as a plug-in hard drive, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the terminal. Furthermore, the computer-readable storage medium can include both internal storage units and external storage devices of the terminal. The computer-readable storage medium is used to store the computer program and other programs and data required by the terminal. The computer-readable storage medium can also be used to temporarily store data that has been output or will be output.

[0075] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0076] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the terminals and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0077] In the several embodiments provided in this application, it should be understood that the disclosed terminals and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices or units, or may be electrical, mechanical or other forms of connection.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. An integrated simulation method for horizontal well fracturing and production prediction in low-permeability reservoirs, characterized in that, Includes the following steps: S1: Construct a geological model of a low-permeability reservoir based on field geological and drilling data; S2: Construct a coupled model of horizontal well fracturing and proppant transport in low-permeability reservoirs, predict the characteristics of hydraulic fractures and proppant placement, and obtain the simulation results of horizontal well fracturing. S3: Combining horizontal well fracturing simulation results with indoor conductivity experiments, predict the overall conductivity of hydraulic fractures; S4: Construct a two-phase flow model for oil and water production in horizontal wells of low-permeability reservoirs, and combine the global conductivity of the hydraulic fractures to predict the oil and water distribution characteristics of the post-compression reservoir and the production of horizontal wells in low-permeability reservoirs, and obtain the prediction results. S5: Evaluate the fracturing results of horizontal wells in low-permeability reservoirs based on the prediction results, and optimize the fracturing construction parameters of horizontal wells.

2. The integrated simulation method for horizontal well fracturing and production prediction in low-permeability reservoirs according to claim 1, characterized in that, The specific methods for constructing geological models of low-permeability oil reservoirs based on field geological and drilling data include: S11: Collect geological, drilling and production data of the target block, establish a three-dimensional structural model and sedimentary facies model, and obtain porosity and permeability property models; S12: Obtain basic reservoir parameters in the horizontal well segmented fracturing stimulation area. These parameters include: maximum horizontal principal stress, minimum horizontal principal stress, vertical stress, interlayer stress difference, stress gradient, reservoir thickness, pore pressure, Young's modulus, and Poisson's ratio.

3. The integrated simulation method for horizontal well fracturing and production prediction in low-permeability reservoirs according to claim 1, characterized in that, The specific methods for constructing a coupled model of horizontal well fracturing and proppant transport in low-permeability oil reservoirs include: S21: Constructing a mathematical model for hydraulic fracture deformation: Based on the displacement discontinuity method, the hydraulic fractures at the mine scale are discretized into rectangular fracture elements. A hydraulic fracture deformation model is established according to the stress-deformation relationship. An induced stress calculation model is established to describe the stress interference between hydraulic fractures during segmented multi-cluster fracturing of horizontal wells. S22: Establish a mathematical model for fracturing fluid flow, including: using Poiseuille's law to describe the fracturing fluid flow in hydraulic fractures, using porous media seepage theory to describe the fracturing fluid seepage process in the reservoir, calculating the fracturing fluid loss based on the fluid pressure relationship between the hydraulic fracture and the reservoir matrix, considering the flow rate differences of different perforation clusters during the segmented multi-cluster fracturing process in horizontal wells, establishing a set of fluid pressure equations using Kirchhoff's law, and solving them using Newton's iteration method to obtain the dynamic flow rate distribution results of each perforation cluster in the segmented multi-cluster fracturing of horizontal wells at different times; S23: Establish a hydraulic fracture propagation model, including: using the equivalent stress intensity criterion as the basis for judging hydraulic fracture propagation; when the equivalent stress intensity factor of the fracture tip element is greater than or equal to the fracture toughness of the rock, the hydraulic fracture propagates; and new fracture elements are added to the current hydraulic fracture tip; the propagation direction of the hydraulic fracture is predicted based on the maximum circumferential stress criterion; and the deflection angle of the hydraulic fracture tip element is calculated. S24: Construct a proppant transport model within hydraulic fractures, including: calculating the density and viscosity of the mixed proppant and fracturing fluid, using a clogging function to describe the proppant's permeability in hydraulic fractures, calculating the corrected proppant settling velocity, and establishing a mathematical model for proppant transport in hydraulic fractures based on Euler's multiphase flow theory. S25: Solve the coupling model of horizontal well fracturing and proppant transport in low-permeability reservoirs, including: based on the hydraulic fracture deformation model and the fracturing fluid flow model, establish a set of control equations for hydraulic fracture and fracturing fluid seepage in the reservoir matrix, a set of control equations for proppant migration in the hydraulic fracture, and a set of fluid-structure coupling equations for hydraulic fracture propagation in the horizontal well segmented multi-cluster fracturing. Iterate the hydraulic fracture width, fluid pressure inside the fracture, proppant concentration inside the fracture, and pore pressure of the reservoir matrix under the same time step using a sequential coupling method.

4. The integrated simulation method for horizontal well fracturing and production prediction in low-permeability reservoirs according to claim 1, characterized in that, The specific method for constructing a two-phase flow model for oil-water production in horizontal wells of low-permeability reservoirs includes: S31: After the horizontal well fracturing simulation is completed, the proppant thickness is calculated based on the hydraulic fracture width and the proppant concentration in the fracture, and the hydraulic fracture unit is divided into filled unit and unfilled unit according to the filling thickness. S32: The conductivity of proppant-filled and unpadded hydraulic fracture elements was obtained through indoor experiments; S33: Calculate the closure stress based on the geostress and hydraulic fracture-induced stress of the target low-permeability reservoir, and perform interpolation based on the conductivity chart to obtain the spatial distribution of conductivity of filled and unfilled fracture units.

5. The integrated simulation method for horizontal well fracturing and production prediction in low-permeability reservoirs according to claim 1, characterized in that, The specific method for constructing a two-phase flow model for oil-water production in horizontal wells of low-permeability reservoirs includes: S41: Establish a mathematical model for two-phase oil-water flow in the matrix of low-permeability oil reservoirs; S42: Establish a mathematical model for two-phase oil-water flow in hydraulic fractures of low-permeability reservoirs; S43: Establish a mathematical model for calculating production after hydraulic fracturing in low-permeability reservoirs; S44: Based on the embedded discrete fracture theory, the flow conduction relationship between the reservoir matrix and hydraulic fractures is established. The mathematical model of two-phase flow in the reservoir matrix and hydraulic fractures is numerically discretized using the finite volume method. A mathematical model of two-phase flow of matrix-fracture-wellbore oil-water under constant pressure production conditions in horizontal wells of low-permeability reservoirs is established.

6. The integrated simulation method for horizontal well fracturing and production prediction in low-permeability reservoirs according to claim 5, characterized in that, The specific methods for predicting the oil-water distribution characteristics and horizontal well production of low-permeability reservoirs after compression, based on the overall conductivity of hydraulic fractures, include: S45: Design key construction parameters for horizontal well fracturing stimulation of reservoirs based on the development needs of low-permeability reservoirs; S46: Simulate horizontal well fracturing and proppant transport in low-permeability reservoirs to obtain hydraulic fracture trajectory, fracture size and proppant placement results; S47: Based on the prediction results of hydraulic fracture geometry parameters and proppant concentration distribution, calculate the overall conductivity of the hydraulic fracture after horizontal well fracturing. S48: Using the full-domain conductivity of hydraulic fractures as input, dynamic simulation of production after horizontal well pressure in low-permeability reservoirs is carried out based on the mathematical model of matrix-fracture-wellbore oil-water two-phase flow. S49: Output the reservoir oil-water distribution and horizontal well production results corresponding to different horizontal well fracturing and stimulation construction schemes.

7. The integrated simulation method for horizontal well fracturing and production prediction in low-permeability reservoirs according to claim 6, characterized in that, The specific methods for evaluating the fracturing results of horizontal wells in low-permeability reservoirs based on prediction results and optimizing horizontal well fracturing parameters include: Based on the prediction results, the cumulative production of horizontal wells under the same production conditions is used as the metric to evaluate the stimulation effect of different horizontal well fracturing construction schemes and optimize the key construction parameters for horizontal well fracturing stimulation in low-permeability reservoirs.

8. An integrated simulation system for horizontal well fracturing and production prediction in low-permeability reservoirs, used to implement the integrated simulation method for horizontal well fracturing and production prediction in low-permeability reservoirs as described in any one of claims 1-7, characterized in that, include: The module comprises a first model building module, a second model building module, a prediction module, a third model building module, and a computation and optimization module. The first model building module is used to build a geological model of a low-permeability oil reservoir based on field geology and drilling data; The second model building module is used to construct a coupled model of horizontal well fracturing and proppant transport in low-permeability reservoirs, predict the characteristics of hydraulic fractures and proppant placement, and obtain the simulation results of horizontal well fracturing. The prediction module is used to combine the results of horizontal well fracturing simulation with the results of indoor conductivity experiments to predict the overall conductivity of hydraulic fractures. The third model is used to construct a two-phase flow model for oil and water production in horizontal wells of low-permeability reservoirs. It combines the full-domain conductivity of hydraulic fractures to predict the oil and water distribution characteristics of the post-compression reservoir and the production of horizontal wells in low-permeability reservoirs, and obtains the prediction results. The calculation and optimization module is used to evaluate the fracturing results of horizontal wells in low-permeability reservoirs based on the prediction results and to optimize the fracturing construction parameters of horizontal wells.

9. An electronic device, comprising: The system includes a processor, an input device, an output device, and a memory, which are interconnected. The memory is used to store a computer program, which includes program instructions. The processor is configured to invoke the program instructions to perform the method as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, the computer program including program instructions that, when executed by a processor, cause the processor to perform the method as described in any one of claims 1-7.

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