A shale gas reservoir horizontal well production analysis method for adjacent well fracturing interference

Abstract

The present application relates to unconventional reservoir pressure modification technical field, in order to solve the problem that the analysis result of prior art is inaccurate, thereby cannot assist horizontal well fracturing construction, a shale gas reservoir horizontal well production adjacent well fracturing interference analysis method is disclosed, the present application is based on the natural fracture model and fracture propagation model constructed to carry out hydraulic fracture propagation prediction, and the adsorption and desorption model of methane and gas-liquid two-phase flow control equation are comprehensively combined, and combined with fracture propagation data, horizontal well production seepage flow model is established, to obtain the reservoir pore pressure based on this;Then, according to initial in-situ stress field and pore pressure, the ground stress field of reservoir after horizontal well production is determined;Then, with initial in-situ stress field and post-production ground stress field, the hydraulic fracture extension prediction of fracturing well is carried out and compared, that is, the interference analysis result can be obtained;The present application improves the accuracy of horizontal well production adjacent well fracturing interference analysis, which can provide guidance for horizontal well fracturing construction.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of interwell interference analysis, and particularly relates to a shale gas reservoir horizontal well production interference analysis method for adjacent well fracturing. BACKGROUND

[0002] As an important unconventional oil and gas resource, shale gas is rich in resources and widely distributed in the world. Therefore, the large-scale and efficient development of shale gas resources is of great significance to the protection of national energy security, the promotion of energy structure transformation and the development of technology. At present, due to the low porosity and low permeability characteristics of the reservoir, efficient reservoir reconstruction measures are the key to the large-scale development of shale gas reservoirs. The continuous development of horizontal well drilling technology and large-scale volume fracturing technology of horizontal wells provides important technical support for the cost reduction and efficiency improvement of shale gas reservoir development. Among them, the horizontal well group constructs an artificial fracture network with high conductivity through volume fracturing technology, increases the exposure area of the reservoir matrix and reduces the fluid seepage pressure difference, so as to improve the development efficiency of underground shale gas resources.

[0003] At present, under the well group development mode, especially for the case of reservoir infilling wells, there is interwell interference between different horizontal wells on the same platform and different platforms. The main problem is that the production of the production well reduces the reservoir energy and affects the fracturing of the well. On the one hand, interwell interference will cause repeated reconstruction of part of the target reservoir area between adjacent horizontal wells, resulting in waste of fracturing resources. On the other hand, the formation pressure depletion will affect the hydraulic fracture extension state of the fracturing well, thereby inducing interwell channeling and under-reconstruction of the target reconstruction area, and further leading to the decrease of the production of the production well and the decrease of the reconstruction effect of the fracturing well. Therefore, it is of great significance to master the interference law of shale gas reservoir horizontal well production on adjacent well fracturing for designing horizontal well group layout, optimizing horizontal well fracturing parameters and improving the overall development effect of shale gas reservoirs.

[0004] Around the problem of interwell interference of shale gas reservoirs, domestic and foreign scholars have carried out a lot of research through field operation monitoring and theoretical numerical simulation. The main aspects include the change of reservoir ground stress caused by horizontal well production, the communication mode of horizontal well fracturing, and the hydraulic fracture extension of the fracturing well adjacent to the production well. However, the existing technical solutions mainly consider the influence of reservoir pore pressure change on the evolution of reservoir ground stress, without considering the comprehensive influence of initial in-situ stress distribution and methane adsorption and desorption. At the same time, the shale reservoir in most numerical models adopts the assumption of homogeneous isotropy and the assumption of single-phase gas flow, without fully considering the influence of natural fracture development and gas-liquid two-phase flow of the reservoir, so that the interference of shale gas reservoir production well on the fracturing well lacks accurate quantitative understanding, and thus the construction basis for horizontal well fracturing cannot be provided. Therefore, based on the foregoing deficiencies, how to provide a shale gas reservoir horizontal well production interference analysis method with high accuracy for adjacent well fracturing has become a problem to be solved. Summary of the Invention

[0005] The technical problem to be solved by this invention is the interference of horizontal well production in shale gas reservoirs with fracturing of adjacent wells. The purpose is to provide an analytical method for the interference of horizontal well production in shale gas reservoirs with fracturing of adjacent wells, which solves the problem of poor analytical accuracy in traditional technology, thus failing to assist in horizontal well fracturing operations.

[0006] This invention is achieved through the following technical solution:

[0007] Firstly, a method for analyzing the interference of horizontal well production in shale gas reservoirs on fracturing of adjacent wells is provided, including:

[0008] Establish a natural fracture model for shale gas reservoirs;

[0009] A segmented multi-cluster fracturing fracture propagation model for horizontal wells was constructed, and the first hydraulic fracture propagation data in the horizontal well was obtained based on the natural fracture model and the segmented multi-cluster fracturing fracture propagation model for horizontal wells.

[0010] An adsorption and desorption model of methane during the production process of shale gas reservoirs was established, and based on the adsorption and desorption model, the first gas-liquid two-phase flow control equation in the reservoir matrix of shale gas reservoirs was constructed.

[0011] Based on the first gas-liquid two-phase flow control equation and the first hydraulic fracture extension data, a horizontal well production seepage model was established, and based on the horizontal well production seepage model, the pore pressure distribution data of the reservoir in the shale gas reservoir was predicted.

[0012] The initial in-situ stress field of the shale reservoir is obtained, and the evolution data of the geostress field of the shale reservoir after horizontal well production is determined based on the initial in-situ stress field and the pore pressure distribution data.

[0013] Using the geostress field evolution data of shale reservoirs and the initial in-situ stress field as boundary conditions, and employing a segmented multi-cluster fracturing fracture propagation model for horizontal wells, the second and third hydraulic fracture propagation data in the fracturing wells were obtained.

[0014] The results of the well-to-well interference analysis were obtained using the second and third hydraulic fracture extension data.

[0015] Based on the above disclosure, the present application first establishes a natural fracture model of the shale gas reservoir, and then constructs a horizontal well segmented multi-cluster fracturing fracture propagation model, and based on the fracture propagation model and the natural fracture model, determines the first hydraulic fracture extension data in the horizontal well; then, a methane adsorption and desorption model in the production process of the shale gas reservoir is established, and based on the adsorption and desorption model, a first gas-liquid two-phase flow control equation in the reservoir matrix in the shale gas reservoir is constructed; then, the horizontal well production seepage model can be established according to the first gas-liquid two-phase flow control equation and the first hydraulic fracture extension data predicted in the foregoing; based on the production seepage model, the pore pressure distribution data of the reservoir in the shale gas reservoir are predicted; wherein, after obtaining the pore pressure distribution data of the reservoir, the present application combines it with the initial in-situ stress field of the shale reservoir to obtain the in-situ stress field evolution data of the shale reservoir after the production of the horizontal well; then, the different hydraulic fracture extension data of the fracturing well adjacent to the horizontal well can be predicted by taking the foregoing in-situ stress field evolution data and the initial in-situ stress field as the boundary conditions and using the foregoing constructed fracture propagation model; finally, the interwell interference analysis result between the horizontal well and the adjacent fracturing well can be obtained according to the hydraulic fracture extension data under the different in-situ stress field boundary conditions.

[0016] Through the above design, the present application constructs a reasonable hydraulic fracture propagation prediction of the horizontal well based on the natural fracture model and the fracture propagation model; at the same time, the first gas-liquid two-phase flow control equation in the reservoir matrix is constructed by comprehensively considering the methane adsorption and desorption model, and the horizontal well production seepage model is established by combining the hydraulic fracture propagation prediction data, so as to obtain the pore pressure distribution data of the reservoir based on the horizontal well production seepage model; then, the in-situ stress field evolution data of the shale reservoir after the production of the horizontal well is determined according to the initial in-situ stress field and the pore pressure distribution data; then, the hydraulic fracture extension data of the fracturing well under different in-situ stress field boundary conditions is predicted by taking the initial in-situ stress field and the in-situ stress field evolution data as the boundary conditions and combining the foregoing fracture propagation model; finally, the interwell interference analysis result can be obtained through the hydraulic fracture extension data under different boundary conditions; in this way, the present application considers the influence of the natural fracture on the hydraulic fracture propagation when predicting the hydraulic fracture propagation, and fully considers the comprehensive influence of the initial in-situ stress distribution, methane adsorption and desorption and gas-liquid two-phase flow when quantifying the influence of the pore pressure change on the in-situ stress of the reservoir; therefore, compared with the traditional technology, the present application improves the accuracy of the analysis of the fracturing interference of the adjacent well by the horizontal well production, and can provide a guidance basis for the fracturing construction design and optimization of the horizontal well.

[0017] In one possible design, the natural fracture model of the reservoir in the shale gas reservoir is established, including:

[0018] Obtaining geological parameters of a shale gas reservoir in which a horizontal well is located, wherein the geological parameters include natural fracture surface density, reservoir area, natural fracture length, and natural fracture azimuth;

[0019] According to the natural fracture surface density and the reservoir area, a natural fracture number model is constructed;

[0020] Based on the natural fracture length, a natural fracture length model is constructed;

[0021] According to the natural fracture azimuth, a natural fracture azimuth model is constructed;

[0022] The natural fracture number model, the natural fracture length model, and the natural fracture azimuth model are used to form the natural fracture model.

[0023] In one possible design, a horizontal well staged multi-cluster fracturing fracture propagation model is constructed, including:

[0024] A rock deformation constitutive equation of a hydraulic fracture stress field under the joint action of in-situ stress and fluid pressure is constructed;

[0025] Obtaining construction parameters and completion parameters of the horizontal well;

[0026] According to the construction parameters and the completion parameters, a fracturing fluid flow control equation in the fracturing fracture propagation process of the horizontal well is constructed;

[0027] The rock deformation constitutive equation and the fracturing fluid flow control equation are used to form a hydraulic fracture width and fluid pressure prediction model;

[0028] Based on the hydraulic fracture width and fluid pressure prediction model, a hydraulic fracture width matrix and a fluid pressure matrix in the hydraulic fracture are calculated;

[0029] According to the hydraulic fracture width matrix, the energy release rate of each hydraulic fracture tip is calculated;

[0030] According to the natural fracture model, the fluid pressure matrix, and the energy release rate of each hydraulic fracture tip, a hydraulic fracture trajectory prediction model and a fracture propagation length model are constructed;

[0031] The fracture propagation length model, the trajectory prediction model, and the hydraulic fracture width and fluid pressure prediction model are used to form the horizontal well staged multi-cluster fracturing fracture propagation model.

[0032] In one possible design, a rock deformation constitutive equation of a hydraulic fracture stress field under the joint action of in-situ stress and fluid pressure is constructed, including:

[0033] obtaining normal stress component and tangential stress component acting on the hydraulic fracture, and a first influence coefficient matrix between normal and normal based on fracture height correction, a second influence coefficient matrix between tangential and tangential based on fracture height correction, a third influence coefficient matrix between normal and tangential based on fracture height correction, and a fourth influence coefficient matrix between tangential and normal based on fracture height correction;

[0034] calculating a comprehensive ground stress matrix acting on the hydraulic fracture according to the normal stress component, the tangential stress component, the third influence coefficient matrix and the second influence coefficient matrix;

[0035] calculating a comprehensive influence coefficient matrix based on the first influence coefficient matrix, the second influence coefficient matrix, the third influence coefficient matrix and the fourth influence coefficient matrix;

[0036] constructing the rock deformation constitutive equation based on the hydraulic fracture width and the fluid pressure in the hydraulic fracture by using the comprehensive ground stress matrix and the comprehensive influence coefficient matrix.

[0037] In one possible design, a fracturing fluid flow control equation in the process of horizontal well fracturing fracture propagation is constructed according to construction parameters and completion parameters, including:

[0038] obtaining a fracturing fluid flow coefficient matrix;

[0039] calculating horizontal wellbore friction and perforation hole friction of each perforation cluster in the horizontal well according to construction parameters and completion parameters;

[0040] calculating fracturing fluid displacement of each perforation cluster based on the horizontal wellbore friction and perforation hole friction of each perforation cluster;

[0041] constructing the fracturing fluid flow control equation based on the hydraulic fracture width and the fluid pressure in the hydraulic fracture by using the fracturing fluid flow coefficient matrix and the fracturing fluid displacement of each perforation cluster.

[0042] In one possible design, a first gas-liquid two-phase flow control equation in the reservoir matrix of a shale gas reservoir is constructed according to the adsorption and desorption model, including:

[0043] obtaining attribute parameters of methane in the shale gas reservoir;

[0044] constructing a gas motion equation of methane according to the attribute parameters;

[0045] constructing the first gas-liquid two-phase flow control equation based on the gas motion equation and the adsorption and desorption model.

[0046] In one possible design, an adsorption and desorption model of methane in the production process of a shale gas reservoir is established, including:

[0047] obtaining a gas constant of methane, and a saturated load and a component adsorption enthalpy change of methane in the shale gas reservoir;

[0048] constructing the adsorption and desorption model according to the gas constant, the saturated load and the component adsorption enthalpy change, and according to the following formula:

[0049]

[0050] In the formula, a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z, and A are constants. denotes the adsorption and desorption model, denotes the saturated load, all denote constants, denotes the component adsorption enthalpy change, denotes the gas constant, denotes temperature, denotes a heterogeneity constant, denotes gas pressure.

[0051] In one possible design, a horizontal well production percolation model is established based on a first gas-liquid two-phase flow control equation and first hydraulic fracture extension data, including:

[0052] obtaining a reservoir matrix permeability;

[0053] calculating an exchange coefficient between a hydraulic fracture and a reservoir matrix according to the first hydraulic fracture extension data and the reservoir matrix permeability;

[0054] constructing a second gas-liquid two-phase flow control equation in the hydraulic fracture according to the exchange coefficient;

[0055] discretizing the first gas-liquid two-phase flow control equation and the second gas-liquid two-phase flow control equation by using a finite volume method to obtain the horizontal well production percolation model.

[0056] In one possible design, shale reservoir geostress field evolution data after horizontal well production is determined according to the initial in-situ stress field and the pore pressure distribution data, including:

[0057] obtaining rock attribute parameters of the shale reservoir;

[0058] constructing a reservoir stress balance equation based on pore pressure change according to the rock attribute parameters and the pore pressure distribution data;

[0059] solving the reservoir stress balance equation to obtain a change value of reservoir stress caused by horizontal well production of the shale gas reservoir;

[0060] obtaining an induced stress field of the hydraulic fracture in the reservoir after horizontal well production of the shale gas reservoir;

[0061] The initial in-situ stress field, the change value of the reservoir stress and the induced stress field are subjected to stress superposition processing to obtain the in-situ stress field evolution data after stress superposition processing.

[0062] In one possible design, the second hydraulic fracture extension data includes a second fracture length and a second fracture width of the fractured well, and the third hydraulic fracture extension data includes a third fracture length and a third fracture width of the fractured well.

[0063] The interwell interference analysis result is obtained by using the second hydraulic fracture extension data and the third hydraulic fracture extension data, and includes:

[0064] The first average fracture length, the first average fracture width and the first fracture length variation coefficient are calculated based on the second fracture length and the second fracture width of the fractured well.

[0065] The second average fracture length, the second average fracture width and the second fracture length variation coefficient are calculated according to the third fracture length and the third fracture width of the fractured well.

[0066] The fracture length change rate is obtained based on the first average fracture length and the second average fracture length.

[0067] The fracture width change rate is obtained according to the first average fracture width and the second average fracture width, and the fracture length variation coefficient change rate is obtained based on the first fracture length variation coefficient and the second fracture length variation coefficient.

[0068] The interwell interference analysis result is generated by using the fracture length change rate, the fracture width change rate and the fracture length variation coefficient change rate.

[0069] In a second aspect, a device for analyzing the interference of a shale gas reservoir horizontal well production on adjacent well fracturing is provided, and the device includes:

[0070] A natural fracture modeling unit is configured to establish a natural fracture model of the shale gas reservoir.

[0071] A hydraulic fracture prediction unit is configured to construct a horizontal well segmented multi-cluster fracturing fracture propagation model, and obtain first hydraulic fracture extension data in the horizontal well according to the natural fracture model and the horizontal well segmented multi-cluster fracturing fracture propagation model.

[0072] A pore pressure prediction unit is configured to establish a methane adsorption and desorption model during shale gas reservoir production, and construct a first gas-liquid two-phase flow control equation in a reservoir matrix in the shale gas reservoir according to the adsorption and desorption model.

[0073] The pore pressure prediction unit is further configured to establish a horizontal well production percolation model based on the first gas-liquid two-phase flow control equation and the first hydraulic fracture extension data, and predict pore pressure distribution data of the shale gas reservoir based on the horizontal well production percolation model.

[0074] The in-situ stress field evolution unit is configured to obtain an initial in-situ stress field of the shale reservoir, and determine in-situ stress field evolution data of the shale reservoir after the horizontal well production based on the initial in-situ stress field and the pore pressure distribution data.

[0075] The hydraulic fracture prediction unit is further configured to take the in-situ stress field evolution data and the initial in-situ stress field of the shale reservoir as boundary conditions respectively, and obtain second hydraulic fracture extension data and third hydraulic fracture extension data in the fractured well by using a horizontal well staged multi-cluster hydraulic fracture propagation model.

[0076] The interwell interference analysis unit is configured to obtain an interwell interference analysis result by using the second hydraulic fracture extension data and the third hydraulic fracture extension data.

[0077] In a third aspect, another device for analyzing interference of shale gas reservoir horizontal well production on adjacent well fracturing is provided, taking the device as an electronic device, comprising a memory, a processor and a transceiver connected in sequence and in communication, wherein the memory is configured to store a computer program, the transceiver is configured to transceive messages, and the processor is configured to read the computer program and execute the shale gas reservoir horizontal well production interference analysis method of the adjacent well fracturing as in the first aspect or any possible design of the first aspect.

[0078] In a fourth aspect, a storage medium is provided, and the storage medium stores instructions, when the instructions are run on a computer, the shale gas reservoir horizontal well production interference analysis method of the adjacent well fracturing as in the first aspect or any possible design of the first aspect is executed.

[0079] In a fifth aspect, a computer program product containing instructions is provided, when the instructions are run on a computer, the shale gas reservoir horizontal well production interference analysis method of the adjacent well fracturing as in the first aspect or any possible design of the first aspect is executed.

[0080] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0081] (1) In the hydraulic fracture propagation prediction of the present application, the influence of natural fractures on hydraulic fracture propagation is considered, and in the quantification of the influence of pore pressure change on reservoir in-situ stress, the comprehensive influence of initial in-situ stress distribution, methane adsorption and desorption and gas-liquid two-phase flow is fully considered; therefore, compared with the traditional technology, the present application improves the accuracy of horizontal well production interference analysis on adjacent well fracturing, and can provide guidance for horizontal well fracturing construction design and optimization.

[0082] (2) The application establishes a reasonable fracture propagation model and a shale gas percolation model based on a natural fracture model, a methane adsorption and desorption model and a gas-liquid two-phase flow control equation in a reservoir matrix, so that the reservoir pore pressure after horizontal well production can be accurately predicted, and the accuracy of subsequent well interference analysis can be improved.

[0083] (3) The application considers the comprehensive influence of initial in-situ stress, production interference stress (i.e. the change value of reservoir stress caused by shale gas reservoir horizontal well production) and fracture-induced stress, and calculates the stress field evolution data of the shale reservoir based on the stress superposition principle, so that the application can obtain reasonable and accurate stress field change data of the shale reservoir after horizontal well production, thereby providing accurate stress field boundary conditions for subsequent production well interference analysis of the fractured well, and the accurate analysis of the interference degree of the production well on the fractured well can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0084] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the application, the drawings needed in the embodiments will be briefly introduced as follows, and it should be understood that the following drawings only show some embodiments of the application, and therefore should not be regarded as a limitation on the scope, and other related drawings can be obtained by those skilled in the art without creative labor. In the drawings:

[0085] Figure 1 The step flowchart of the shale gas reservoir horizontal well production interference analysis method for adjacent wells provided by the embodiment of the application is shown in the figure;

[0086] Figure 2 The natural fracture modeling result in the shale gas reservoir provided by the embodiment of the application is shown in the figure;

[0087] Figure 3 The schematic diagram of the horizontal well segmented multi-cluster hydraulic fracture extension trajectory and fracture width distribution simulation result provided by the embodiment of the application is shown in the figure;

[0088] Figure 4 The schematic diagram of the horizontal well production percolation model prediction reservoir pore pressure distribution result provided by the embodiment of the application is shown in the figure;

[0089] Figure 5 The schematic diagram of the horizontal well production induced horizontal maximum principal stress change result provided by the embodiment of the application is shown in the figure;

[0090] Figure 6 The schematic diagram of the horizontal well production induced horizontal minimum principal stress change result provided by the embodiment of the application is shown in the figure;

[0091] Figure 7 A schematic diagram of the induced stress distribution result of the hydraulic fracture of the production well along the direction of the horizontal minimum principal stress provided by the embodiment of the present application;

[0092] Figure 8 A schematic diagram of the induced stress distribution result of the hydraulic fracture of the production well along the direction of the horizontal maximum principal stress provided by the embodiment of the present application;

[0093] Figure 9 A schematic diagram of the extension trajectory and the fracture width distribution result of the hydraulic fracture of the fracturing well provided by the embodiment of the present application, which considers the influence of the production well;

[0094] Figure 10 A schematic diagram of the extension trajectory and the fracture width distribution result of the hydraulic fracture of the fracturing well provided by the embodiment of the present application, which does not consider the influence of the production well. DETAILED DESCRIPTION

[0095] In order to make the objectives, technical solutions and advantages of the present application clearer, further detailed description will be made to the present application with reference to the embodiments and the accompanying drawings, the illustrative embodiments of the present application and the description thereof are only used to explain the present application, and should not be regarded as limiting the present application; it should be understood that although the terms first, second, etc. can be used herein to describe various units, these units should not be limited by these terms. These terms are only used to distinguish one unit from another unit. For example, the first unit can be called the second unit, and similarly, the second unit can be called the first unit, without departing from the scope of the example embodiments of the present application.

[0096] Embodiment:

[0097] Reference Figure 1As shown, the shale gas reservoir horizontal well production analysis method provided by the embodiment constructs a reasonable natural fracture model and a fracture propagation model to predict the hydraulic fracture propagation of the horizontal well; at the same time, a first gas-liquid two-phase flow control equation in the reservoir matrix is constructed by comprehensively considering the methane adsorption and desorption model, and a horizontal well production seepage model is established by combining the hydraulic fracture propagation prediction data, so as to obtain the pore pressure distribution data of the reservoir based on the horizontal well production seepage model; then, the in-situ stress field evolution data of the shale reservoir after the production of the horizontal well are determined according to the initial in-situ stress field and the pore pressure distribution data; then, the initial in-situ stress field and the in-situ stress field evolution data are taken as boundary conditions respectively, and the hydraulic fracture extension data of the fractured well under different in-situ stress field boundary conditions are predicted by combining the foregoing fracture propagation model; finally, the interwell interference analysis result can be obtained through the hydraulic fracture extension data under different boundary conditions; in this way, in the hydraulic fracture propagation prediction, the influence of the natural fracture on the hydraulic fracture propagation is considered, and in the quantification of the influence of the pore pressure change on the in-situ stress of the reservoir, the comprehensive influence of the initial in-situ stress distribution, the methane adsorption and desorption, and the gas-liquid two-phase flow is fully considered; therefore, compared with the traditional technology, the accuracy of the analysis of the horizontal well production on the interference of the fracturing of the adjacent well is improved, which can provide a guidance basis for the fracturing design and optimization of the horizontal well; wherein, the method can be but is not limited to operated at the interwell interference analysis end; optionally, the interwell interference analysis end can be but is not limited to a personal computer or a server; it can be understood that the foregoing execution subject does not constitute a limitation on the embodiments of the present application, and correspondingly, the operation steps of the method can be but are not limited to the steps S1-S7 shown below.

[0098] S1. Establish a natural fracture model of a shale gas reservoir; in specific application, the natural fracture modeling in the shale gas reservoir (i.e., the natural fracture modeling in the shale reservoir) is completed according to the geological parameters of the shale gas reservoir where the horizontal well is located and by combining a statistical method, which mainly models the number, length and orientation of the natural fractures; optionally, the natural fracture modeling process is shown in the steps S11-S15.

[0099] S11. Obtain the geological parameters of the shale gas reservoir where the horizontal well is located, wherein the geological parameters include the natural fracture surface density, the reservoir area, the length of the natural fracture and the azimuth angle of the natural fracture; in the embodiment, the foregoing geological parameters are obtained through geological exploration and are pre-stored in the interwell interference analysis end and can be called when used; after obtaining the geological parameters, the natural fracture modeling process is shown in the steps S12-S15.

[0100] S12. According to the natural fracture surface density and the reservoir area, a natural fracture number model is constructed; in a specific application, for example, but not limited to, the following formula (1) is used to construct the natural fracture number model.

[0101] (1)

[0102] In the above formula (1), represents the natural fracture number, represents the natural fracture surface density, represents the reservoir area.

[0103] Wherein, the natural fracture number is used to judge the approaching angle between the hydraulic fracture and each natural fracture in the intersection criterion of the following step S27; thus, after obtaining the natural fracture number model, the natural fracture length modeling can be performed, the process of which is shown in the following step S13.

[0104] S13. Based on the length of the natural fracture, a natural fracture length model is constructed; in a specific implementation, the average fracture length and the fracture length standard deviation are calculated according to the length of the natural fracture, and then the natural fracture length model is constructed according to the average fracture length and the fracture length standard deviation; wherein, the natural fracture length model is shown in the following formula (2).

[0105] (2)

[0106] In the above formula (2), represents the natural fracture length model, represents the average fracture length, represents the fracture length standard deviation, and represents that the natural fracture length model is subject to normal distribution, that is, the natural fracture length conforms to normal distribution.

[0107] Thus, after constructing the natural fracture length model, the natural fracture azimuth model can be constructed, the process of which is shown in the following step S14.

[0108] S14. According to the azimuth of the natural fracture, a natural fracture azimuth model is constructed; in a specific implementation, for example, but not limited to, the following formula (3) is used to construct the natural fracture azimuth model.

[0109] (3)

[0110] In the above formula (3), represents the natural fracture azimuth model, represents the average azimuth of the natural fracture (i.e. obtained by the azimuth of the natural fracture in the foregoing geological parameters), represents a random constant between 0 and 1, represents a deviation coefficient.

[0111] Thus, by the aforementioned formula (1) - formula (3), the natural fracture data, length and azimuth angle model is constructed, and then based on this, the natural fracture model is composed, and the process is shown in the following step S15.

[0112] S15. The natural fracture model is composed by using the natural fracture number model, the natural fracture length model and the natural fracture azimuth angle model.

[0113] Thus, by the aforementioned steps S11-S15, the number, length and azimuth of natural fractures are obtained, which can be used for subsequent horizontal well staged multi-cluster fracturing fracture propagation simulation under the influence of natural fractures; wherein, the fracture propagation simulation process is shown in the following step S2.

[0114] S2. The horizontal well staged multi-cluster fracturing fracture propagation model is constructed, and the first hydraulic fracture extension data in the horizontal well is obtained according to the natural fracture model and the horizontal well staged multi-cluster fracturing fracture propagation model; in specific application, the rock deformation constitutive equation of the hydraulic fracture stress field and the fracturing fluid flow control equation in the process of horizontal well fracturing fracture propagation are first constructed, and then the hydraulic fracture width and fluid pressure prediction model is constructed based on the aforementioned two models; then, the hydraulic fracture trajectory prediction model and the fracture propagation length model are constructed; finally, the horizontal well staged multi-cluster fracturing fracture propagation model is generated by combining the three models of the aforementioned width, trajectory and length.

[0115] Wherein, the specific modeling process can be but not limited to the following steps S21-S28.

[0116] S21. The rock deformation constitutive equation under the combined action of in-situ stress and fluid pressure of the hydraulic fracture stress field is constructed; in specific application, the rock deformation constitutive equation under the combined action of in-situ stress and fluid pressure of the hydraulic fracture stress field is established based on the displacement discontinuity method algorithm; wherein, the rock deformation constitutive equation is an equation about hydraulic fracture width and fluid pressure, that is, the aforementioned hydraulic fracture width and fluid pressure are unknown quantities, therefore, by establishing the equation, the solution is carried out, so as to realize the prediction of the width and fluid pressure in the hydraulic fracture after the hydraulic fracture propagation in the horizontal well.

[0117] Wherein, the construction process of the aforementioned rock deformation constitutive equation is shown in the following steps S21a-S21d.

[0118] S21a. Obtain the normal stress component and the tangential stress component acting on the hydraulic fracture, and a first influence coefficient matrix between the normal and the normal based on the fracture height correction, a second influence coefficient matrix between the tangential and the tangential based on the fracture height correction, a third influence coefficient matrix between the normal and the tangential based on the fracture height correction, and a fourth influence coefficient matrix between the tangential and the normal based on the fracture height correction.

[0119] In the embodiment, the four influence coefficient matrices and the two stress components are calculated by the displacement discontinuity method and the elastic mechanics method. Specifically, for the four influence coefficient matrices, the calculation process is as follows: (1) a geometric model of the hydraulic fracture in the shale reservoir is established (the fracture can be a one-dimensional line segment or a two-dimensional surface), and the geometric model is divided into boundary element grids (i.e. fracture grids); (2) the grid size, the distance and the positional relationship between the grids are calculated according to the node coordinates of the boundary element grids; (3) the four influence coefficient matrices, i.e. the influence coefficient matrix between the normal and the normal (describing the interaction between the normal fractures), the influence coefficient matrix between the tangential and the tangential (describing the interaction between the tangential fractures), the influence coefficient matrix between the normal and the tangential (describing the interaction between the normal fractures and the tangential fractures), and the influence coefficient matrix between the tangential and the normal (describing the interaction between the tangential fractures and the normal fractures), are calculated by using the displacement discontinuity method according to the rock mechanics parameters (Young's modulus, Poisson's ratio) of the shale reservoir and the calculation results in (2). Of course, the calculation method of the influence coefficient matrices is a common method for constructing the rock deformation constitutive relation, and the calculation process is not described herein.

[0120] Similarly, the normal stress component and the tangential stress component acting on the hydraulic fracture can be directly calculated based on the in-situ stress measurement data (i.e. the aforementioned original stress field) of the shale reservoir and the boundary element grid coordinate information. This is a general calculation method for the normal and tangential stress components, and the principle is not described herein.

[0121] Therefore, after obtaining the four influence coefficient matrices and the two stress components, the comprehensive stress matrix and the comprehensive influence coefficient matrix can be calculated, and the process is shown in the following steps S21b and S21c.

[0122] S21b. Calculate the comprehensive stress matrix acting on the hydraulic fracture according to the normal stress component, the tangential stress component, the third influence coefficient matrix and the second influence coefficient matrix. In specific implementation, the following formula (4) can be used to calculate the comprehensive stress matrix.

[0123] (4)

[0124] In the above formula (4), denotes the comprehensive in-situ stress matrix, denotes the normal stress component and the tangential stress component in sequence, denotes the third influence coefficient matrix and the second influence coefficient matrix in sequence.

[0125] After the comprehensive in-situ stress matrix is calculated, the calculation of the comprehensive influence coefficient matrix can be performed, and the process is shown in the following step S21c.

[0126] S21c. Based on the first influence coefficient matrix, the second influence coefficient matrix, the third influence coefficient matrix and the fourth influence coefficient matrix, the comprehensive influence coefficient matrix is calculated; in this embodiment, for example, but not limited to, the following formula (5) can be used to calculate the comprehensive influence coefficient matrix.

[0127] (5)

[0128] In the above formula (5), denotes the comprehensive influence coefficient matrix, denotes the first influence coefficient matrix, the third influence coefficient matrix, the second influence coefficient matrix and the fourth influence coefficient matrix in sequence.

[0129] Thus, based on the aforementioned formula (4) and formula (5), the comprehensive in-situ stress matrix and the comprehensive influence coefficient matrix are calculated, and then based on this, the aforementioned rock deformation constitutive equation can be constructed, and the process is shown in the following step S21d.

[0130] S21d. The comprehensive in-situ stress matrix and the comprehensive influence coefficient matrix are used to construct the rock deformation constitutive equation based on the hydraulic fracture width and the fluid pressure in the hydraulic fracture; in specific implementation, one of the following disclosed rock deformation constitutive equations can be used, but not limited to, as shown in the following formula (6).

[0131] (6)

[0132] The above formula (6) represents the rock deformation constitutive equation, wherein, denotes the hydraulic fracture width matrix and the fluid pressure matrix in the hydraulic fracture in sequence.

[0133] Thus, by the foregoing steps S21a-S21d, the rock deformation constitutive equation can be constructed; meanwhile, it can be known from the foregoing formula (6) that the hydraulic fracture width and the fluid pressure in the hydraulic fracture can be predicted by solving the equation; however, there are two unknown quantities in the foregoing formula (6), thus, one equation cannot be solved, based on this, the embodiment establishes the fracturing fluid flow control equation in the process of hydraulic fracture propagation of the horizontal well to form an equation set with the foregoing rock deformation constitutive equation, so as to jointly solve, and obtain the width and fluid pressure matrix of the hydraulic fracture in the process of hydraulic fracture propagation of the horizontal well.

[0134] The construction process of the fracturing fluid flow control equation is shown in the following steps S22 and S23.

[0135] S22. Obtain the construction parameters and completion parameters of the horizontal well; in the embodiment, the completion parameters may, but are not limited to, include: the total number of perforation clusters in the horizontal well, the number of perforations in each perforation cluster, the perforation diameter, the inner diameter of the horizontal wellbore corresponding to each perforation cluster, and the length of the horizontal wellbore; and the construction parameters may, but are not limited to, include: the fracturing fluid viscosity, the fracturing fluid density, and the fracturing fluid displacement in the horizontal wellbore corresponding to each perforation cluster, and the total fracturing fluid displacement.

[0136] Thus, after obtaining the construction parameters and completion parameters of the horizontal well, the fracturing fluid flow control equation in the process of hydraulic fracture propagation of the horizontal well can be constructed, and the process is shown in the following step S23.

[0137] S23. According to the construction parameters and completion parameters, the fracturing fluid flow control equation in the process of hydraulic fracture propagation of the horizontal well is constructed; in the specific implementation, the fracturing fluid flow model in the process of hydraulic fracture propagation of the horizontal well is established, wherein, in the embodiment, the Poiseuille law is used to describe the flow of the fracturing fluid in the hydraulic fracture, and the model can be expressed as:

[0138] (7)

[0139] The formula (7) represents the fracturing fluid flow model, wherein, represents time, represents the flow direction of the fluid in the hydraulic fracture, represents the width of the hydraulic fracture, represents the fluid pressure in the hydraulic fracture, represents the fracturing fluid viscosity of the horizontal wellbore corresponding to each perforation cluster in the construction parameters, represents the fracturing fluid displacement of the source term fracture element, that is, the fracturing fluid displacement into each perforation cluster in the process of horizontal well staged multi-cluster fracturing, The fracturing fluid filtration term of the hydraulic fracture element can be, but is not limited to, calculated by the Carter filtration model or the embedded discrete fracture model.

[0140] It can be seen from the above formula (7) that the fracturing fluid flow model also contains the parameter terms of the hydraulic fracture width and the fluid pressure, and therefore, the unknown parameters in formula (7) are only the hydraulic fracture width and the fluid pressure; thus, the present embodiment establishes the fracturing fluid flow control equation by calculating the fracturing fluid discharge of each perforation cluster and discretizing the above formula (7). , so that the unknown parameters of formula (7) are only the hydraulic fracture width and the fluid pressure; thus, the present embodiment establishes the fracturing fluid flow control equation by calculating the fracturing fluid discharge of each perforation cluster and discretizing the above formula (7).

[0141] For example, but not limited to, the following steps S23a-S23d are used to establish the fracturing fluid flow control equation.

[0142] S23a. Obtain the fracturing fluid flow coefficient matrix; in specific implementation, it can be but not limited to obtained by using the finite volume method digital discretization, and pre-stored in the interwell interference analysis end, so as to directly read when constructing the fracturing fluid flow control equation; then, the horizontal wellbore friction and perforation hole friction of each perforation cluster in the horizontal well can be calculated according to the above construction parameters and completion parameters, so as to subsequently calculate the fracturing fluid discharge of each perforation cluster according to the above horizontal wellbore friction and perforation hole friction; wherein, the calculation process of the horizontal wellbore friction and the perforation hole friction is shown in the following step S23b.

[0143] S23b. Calculate the horizontal wellbore friction and perforation hole friction of each perforation cluster in the horizontal well according to the construction parameters and completion parameters; in specific implementation, for the horizontal wellbore friction of any perforation cluster, it can be but not limited to calculated according to the fracturing fluid viscosity and fracturing fluid discharge in the above geological parameters, and the horizontal wellbore inner diameter and horizontal wellbore length in the completion parameters, and according to the following formula (8).

[0144] (8)

[0145] In the above formula (8), represents the horizontal wellbore friction of the any perforation cluster, represents the fracturing fluid viscosity of the horizontal wellbore corresponding to the any perforation cluster, represents the length of the horizontal wellbore corresponding to the any perforation cluster, represents the inner diameter of the horizontal wellbore corresponding to the any perforation cluster, represents the fracturing fluid discharge in the horizontal wellbore corresponding to the any perforation cluster.

[0146] Similarly, for any perforation cluster, the perforation hole friction of the any perforation cluster can be but not limited to calculated according to the following formula (9).

[0147] (9)

[0148] In the above formula (9), represents the perforation hole friction of the any perforation cluster, represents the fracturing fluid viscosity in the horizontal wellbore corresponding to the any perforation cluster, represents the hole erosion correction coefficient, represents the number of perforations in the any perforation cluster, represents the perforation hole diameter in the any perforation cluster, represents the fracturing fluid flow rate into the any perforation cluster.

[0149] Thus, by the aforementioned formula (8) and formula (9), the horizontal wellbore friction and the perforation hole friction of each perforation cluster can be calculated, and then, based on this, the fracturing fluid flow rate of each perforation cluster can be calculated, the process of which is shown in the following step S23c.

[0150] S23c. Based on the horizontal wellbore friction and the perforation hole friction of each perforation cluster, the fracturing fluid flow rate of each perforation cluster is calculated; in specific applications, for example, but not limited to, the pressure balance equation set of the horizontal wellbore heel is established according to the Kirchhoff law, and the Newton iteration is used in combination with the flow conservation equation to solve the fracturing fluid flow rate into each perforation cluster in the horizontal well fracturing process.

[0151] wherein the calculation formula of the fracturing fluid flow rate is:

[0152] (10)

[0153] In the above formula (10), represents the fracturing fluid flow rate into each perforation cluster at the n+1th iteration, represents the fracturing fluid flow rate into each perforation cluster at the nth iteration, represents the first intermediate parameter at the nth iteration, represents the second intermediate parameter at the nth iteration, represents the total number of perforation clusters.

[0154] wherein:

[0155] (11)

[0156] (12)

[0157] and (13)

[0158] In formula (11), represents the horizontal wellbore friction, the perforation hole friction and the inlet fluid pressure of the fracturing fluid through the perforation hole of the first perforation cluster into the hydraulic fracture (which can be obtained according to historical data), horizontal wellbore friction, perforation hole friction, and entry fluid pressure of the fracturing fluid into the hydraulic fracture through the perforation hole in the second perforation cluster, horizontal wellbore friction, perforation hole friction, and entry fluid pressure of the fracturing fluid into the hydraulic fracture through the perforation hole in the second perforation cluster, horizontal wellbore friction, perforation hole friction, and entry fluid pressure of the fracturing fluid into the hydraulic fracture through the perforation hole in the second perforation cluster, horizontal wellbore friction, perforation hole friction, and entry fluid pressure of the fracturing fluid into the hydraulic fracture through the perforation hole in the second perforation cluster, horizontal wellbore friction, perforation hole friction, and entry fluid pressure of the fracturing fluid into the hydraulic fracture through the perforation hole in the second perforation cluster, horizontal wellbore friction, perforation hole friction, and entry fluid pressure of the fracturing fluid into the hydraulic fracture through the perforation hole in the second perforation cluster, horizontal wellbore friction, perforation hole friction, and entry fluid pressure of the fracturing fluid into the hydraulic fracture through the perforation hole in the second perforation cluster.

[0159] in formula (12), Qn represents the fracturing fluid flow rate into the nth perforation cluster. in formula (12), Qn represents the fracturing fluid flow rate into the nth perforation cluster.

[0160] in formula (13), Qn+1 represents the fracturing fluid flow rate into the nth perforation cluster at the n+1th iteration. in formula (13), Qn+1 represents the fracturing fluid flow rate into the nth perforation cluster at the n+1th iteration. in formula (13), Qn+1 represents the fracturing fluid flow rate into the nth perforation cluster at the n+1th iteration. in formula (13), Qn+1 represents the fracturing fluid flow rate into the nth perforation cluster at the n+1th iteration. in formula (13), Qn+1 represents the fracturing fluid flow rate into the nth perforation cluster at the n+1th iteration. in formula (13), Qn+1 represents the fracturing fluid flow rate into the nth perforation cluster at the n+1th iteration.

[0161] Thus, after the fracturing fluid flow rates of the perforation clusters are calculated by the aforementioned formula (10) to formula (13), the fracturing fluid flow control equation can be constructed by combining the fracturing fluid flow coefficient matrix, as shown in the following step S23d.

[0162] S23d. Constructing the fracturing fluid flow control equation based on the hydraulic fracture width and the fluid pressure in the hydraulic fracture by using the fracturing fluid flow coefficient matrix and the fracturing fluid flow rates of the perforation clusters; in this embodiment, the finite volume method is used to discretize the fracturing fluid flow model in the aforementioned hydraulic fracture, thereby constructing the fracturing fluid flow control equation.

[0163] Alternatively, the fracturing fluid flow control equation is shown in the following formula (14).

[0164] (14)

[0165] in formula (14), A represents the fracturing fluid flow coefficient matrix, in formula (14), A represents the fracturing fluid flow coefficient matrix, in formula (14), Pn represents the fluid pressure matrix at the nth iteration, in formula (14), Pn represents the fluid pressure matrix at the nth iteration, in formula (14), Wn represents the hydraulic fracture width matrix at the nth iteration, in formula (14), Wn represents the hydraulic fracture width matrix at the nth iteration, in formula (14), Wn represents the hydraulic fracture width matrix at the nth iteration, represents the hydraulic fracture element source term matrix at the time step t (i.e., the hydraulic fracture element source term matrix at the time step t is the hydraulic fracture fluid injection rate into each perforation cluster at the time step t), represents the time step; of course, at the initial time, the hydraulic fracture element source term matrix is the hydraulic fracture fluid injection rate into each perforation cluster calculated in the foregoing. Thus, after the hydraulic fracture fluid flow control equation is constructed through the foregoing steps S23a-S23d, the equation group (i.e., the hydraulic fracture width and fluid pressure prediction model described below) can be composed by combining the rock deformation constitutive equation, so as to predict the width and fluid pressure of the hydraulic fracture in the horizontal well during the expansion, and the construction process of the equation group is shown in the following step S24.

[0166] S24. Utilize the rock deformation constitutive equation and the hydraulic fracture fluid flow control equation to compose the hydraulic fracture width and fluid pressure prediction model; in the present embodiment, after the hydraulic fracture width and fluid pressure prediction model is constructed, the width and fluid pressure of the hydraulic fracture in the horizontal well during the expansion can be predicted, and the process is shown in the following step S25.

[0167] S25. Based on the hydraulic fracture width and fluid pressure prediction model, calculate the hydraulic fracture width matrix and the fluid pressure matrix in the hydraulic fracture; in specific implementation, the fluid-solid coupling nonlinear equation group (i.e., the hydraulic fracture width matrix and the fluid pressure matrix in the hydraulic fracture) is composed by combining the rock deformation constitutive equation and the hydraulic fracture fluid flow control equation in the hydraulic fracture; then, the hydraulic fracture width matrix and the fluid pressure matrix in the hydraulic fracture are obtained through numerical iteration solution; of course, the width and fluid pressure of each hydraulic fracture at different time steps are also obtained, and the iteration solution method is a common way for equation group solution, and the iteration solution process is not described herein.

[0168] S25. Based on the hydraulic fracture width and fluid pressure prediction model, calculate the hydraulic fracture width matrix and the fluid pressure matrix in the hydraulic fracture; in specific implementation, the fluid-solid coupling nonlinear equation group (i.e., the hydraulic fracture width matrix and the fluid pressure matrix in the hydraulic fracture) is composed by combining the rock deformation constitutive equation and the hydraulic fracture fluid flow control equation in the hydraulic fracture; then, the hydraulic fracture width matrix and the fluid pressure matrix in the hydraulic fracture are obtained through numerical iteration solution; of course, the width and fluid pressure of each hydraulic fracture at different time steps are also obtained, and the iteration solution method is a common way for equation group solution, and the iteration solution process is not described herein.

[0169] After the hydraulic fracture width matrix (i.e., the first fracture width) and the fluid pressure matrix in the hydraulic fracture of each hydraulic fracture at different time steps are obtained, the shale reservoir hydraulic fracture expansion prediction can be performed based thereon, and the process is shown in the following steps S26-S28.

[0170] S26. According to the hydraulic fracture width matrix, calculate the energy release rate of each hydraulic fracture tip; in specific implementation, for example, the width of the hydraulic fracture, the Young's modulus and the Poisson's ratio of the rock of the shale reservoir can be used to calculate the energy release rate of each hydraulic fracture at different time steps under the framework of linear elastic theory; wherein the calculation formula of the energy release rate is: , wherein, represents the energy release rate of any hydraulic fracture at any time step, represents the Young's modulus,​ Poisson's ratio represents the reservoir rock. The tensile stress intensity factor and shear stress intensity factor are represented sequentially. Based on fracture mechanics theory, Young's modulus, Poisson's ratio, and the crack width obtained in step S21 above are used. The parameters are calculated (this is a commonly used calculation technique for tensile stress intensity factor and shear stress intensity factor, the principle of which will not be elaborated here); thus, based on the aforementioned step S26, after calculating the energy release rate of each hydraulic fracture in each horizontal well at different time steps, the hydraulic fracture trajectory and fracture propagation length model can be constructed by combining the aforementioned natural fracture model and the fluid pressure matrix of each hydraulic fracture in the horizontal well at different time steps, as shown in step S27 below.

[0171] S27. Based on the natural fracture model, the fluid pressure matrix, and the energy release rate at the tips of each hydraulic fracture, a trajectory prediction model and a fracture propagation length model for hydraulic fractures are constructed. In this embodiment, the maximum energy release rate criterion and the maximum circumferential stress criterion are used to predict whether hydraulic fractures in a horizontal well will propagate in the reservoir and the direction of propagation. The calculation expressions for the propagation conditions and propagation direction are as follows:

[0172] (15)

[0173] (16)

[0174] In the above formula (15), This represents the critical energy release rate for the propagation of hydraulic fractures in the reservoir matrix, which is a preset value.

[0175] In the above formula (16), Indicates the deflection angle of the hydraulic fracture propagation. , These represent the tensile stress intensity factor and the shear stress intensity factor, respectively.

[0176] Thus, when the energy release rate of any hydraulic crack at any time step is greater than the critical energy release rate, crack propagation will occur. At this time, the propagation direction can be calculated according to the aforementioned formula (16).

[0177] Then, based on the natural fracture model and the aforementioned hydraulic fracture width, and using the intersection criterion, the propagation of the hydraulic fracture after encountering a natural fracture can be described. The trajectory prediction model corresponding to the intersection criterion is as follows:

[0178] (17)

[0179] In the above formula (17), denotes the circumferential stress and shear stress of the natural fracture due to the tip stress field of any hydraulic fracture, denotes the tensile strength of the rock of the shale reservoir, denotes the in-situ fluid pressure at the intersection point of the any hydraulic fracture and the natural fracture (in fact, it is the in-situ fluid pressure value in the fluid pressure matrix calculated by the hydraulic fracture width and fluid pressure prediction model), denotes the shear strength of the natural fracture (a preset parameter), denotes the friction coefficient of the natural fracture wall (a preset parameter), denotes the approaching angle, and the calculation formula is , denotes the azimuth angle of the natural fracture, denotes the angle of the tip of the hydraulic fracture, denotes the critical energy release rate of the any hydraulic fracture along the natural fracture, denotes the energy release rate of the any hydraulic fracture along the natural fracture, wherein, when is greater than or equal to , the hydraulic fracture begins to expand along the natural fracture; denotes the included angle between the hydraulic fracture and the natural fracture, denotes the tensile strength of the rock of the reservoir, denotes the horizontal minimum principal stress of the reservoir.

[0180] wherein, may be but is not limited to being calculated by using the hydraulic fracture width, Young's modulus and Poisson's ratio under the online elastic theory framework, which is a common calculation method of the circumferential stress and shear stress of the natural fracture due to the hydraulic fracture, and the calculation process is not described here. At the same time, based on the natural fracture length model in the natural fracture model, the length of any natural fracture in the reservoir is obtained, and the natural fracture length is taken as the boundary condition of the hydraulic fracture expanding along the natural fracture. When the expansion reaches the natural fracture length, the hydraulic fracture stops expanding along the natural fracture.

[0181] Specifically, the function of the aforementioned formula (17) is: (1) to determine whether the hydraulic fracture can pass through the natural fracture: by calculating the circumferential stress and shear stress of the hydraulic fracture tip acting on the natural fracture, and comparing it with the tensile strength of the reservoir rock and the shear strength of the natural fracture, it is determined whether the hydraulic fracture can pass through the natural fracture; (2) to determine whether the hydraulic fracture can activate the natural fracture: when the hydraulic fracture cannot pass through the natural fracture, the formula can be used to determine whether the hydraulic fracture can activate the natural fracture, making it a new fracture propagation path; thus, combined with the aforementioned formula (16), the propagation direction of the hydraulic fracture can be determined when the hydraulic fracture passes through or activates the natural fracture, thereby obtaining different propagation trajectories; of course, the aforementioned formula (17) is for each hydraulic fracture, that is, when the data such as the fracture width of the tip unit of different hydraulic fractures at different times are substituted, the propagation trajectory of different hydraulic fractures at different time steps can be obtained.

[0182] Thus, by combining the aforementioned propagation trajectory prediction model and the aforementioned propagation direction (i.e., propagation deflection angle), the propagation trajectory of each hydraulic fracture at different time steps can be simulated; at the same time, a fracture propagation length model can be constructed based on the magnitude of the energy release rate.

[0183] The crack propagation length model is shown in the following formula (18).

[0184] (18)

[0185] In formula (18), This represents the expansion step size of the j-th hydraulic fracture at one time step. This indicates the maximum running step size (a preset value). This represents the energy release rate of the j-th hydraulic fracture at one time step. This represents the maximum energy release rate among all hydraulic fractures within a time step, i.e. ,in, Indicates the first The energy release rate corresponding to each hydraulic fracture, and This represents the total number of hydraulic fractures.

[0186] Thus, using the aforementioned formula (18), the expansion step of the hydraulic fracture at different time steps can be calculated. Based on this, for any hydraulic fracture, the expansion step of its fracture length at all time steps is summed and the original length is added to obtain the fracture length of that hydraulic fracture (i.e., the first fracture length). Then, by combining the aforementioned hydraulic fracture width and fluid pressure prediction model, the fracture width of each hydraulic fracture can be obtained.

[0187] After the crack propagation length model and the trajectory prediction model are constructed, the hydraulic fracture width and fluid pressure prediction model can be combined to form a horizontal well staged multi-cluster fracturing crack propagation model, and the process is shown in the following step S28.

[0188] S28. The crack propagation length model, the trajectory prediction model, and the hydraulic fracture width and fluid pressure prediction model are used to form the horizontal well staged multi-cluster fracturing crack propagation model.

[0189] Through the above design, after obtaining the hydraulic fracture width and the fluid pressure in the hydraulic fracture, the energy release rate of each hydraulic fracture is calculated to determine whether each hydraulic fracture propagates, and the propagation direction is obtained using the aforementioned formula (16). Then, the intersection criterion is used to describe the propagation of the hydraulic fracture after encountering the natural fracture, that is, the aforementioned formula (17) is used in combination with the natural fracture model to obtain the propagation of the hydraulic fracture after encountering the natural fracture (that is, the azimuth angle and other parameters of the natural fracture are substituted into the formula corresponding to the intersection criterion to obtain the crack propagation), and then the crack propagation step is obtained using the aforementioned formula (18). Based on this, at each time step, the hydraulic fracture propagation path can be determined using the aforementioned hydraulic fracture propagation deflection angle and the intersection criterion, and finally, the new crack length propagation step is added to the crack tip at the previous time step based on the crack obtained at the previous time step, and the new crack has a deflection angle, and the hydraulic fracture at the current time step can be obtained. Based on this, the hydraulic fracture width and the fluid pressure in the crack are recalculated through iteration, and then the crack propagation direction and the crack length at the next time step are determined, and the extension prediction of the hydraulic fracture is completed.

[0190] Therefore, through the aforementioned steps S21-S28, the horizontal well staged multi-cluster fracturing crack propagation model can be used to simulate the extension results of the hydraulic fracturing cracks, that is, the trajectory, crack length, and crack width of each hydraulic fracture are calculated. Then, the crack length, crack width, and crack trajectory can be used to form the first hydraulic fracture extension data in the horizontal well.

[0191] After the hydraulic fracture extension prediction is completed, the reservoir pore pressure distribution data can be predicted, and the process is shown in the following steps S3 and S4.

[0192] S3. A methane adsorption and desorption model in the production process of a shale gas reservoir is established, and a first gas-liquid two-phase flow control equation in the reservoir matrix of the shale gas reservoir is constructed based on the adsorption and desorption model. In specific implementation, one of the construction processes of the adsorption and desorption model is disclosed, which is: first, the gas constant of methane, and the saturation load and component adsorption enthalpy of methane in the shale gas reservoir are obtained. Then, the adsorption and desorption model is constructed based on the gas constant, the saturation load, and the component adsorption enthalpy.

[0193] Optionally, the following formula (19) can be used to construct the adsorption and desorption model.

[0194] (19)

[0195] In the above formula (19), represents the adsorption and desorption model (which actually represents the adsorption volume per unit mass of medium), represents the saturation load, all represent constants, represents the component adsorption enthalpy change, represents the gas constant, represents the temperature, represents the heterogeneity constant, represents the gas pressure, i.e. the pressure of the methane gas.

[0196] After the adsorption and desorption model of methane is constructed, the first gas-liquid two-phase flow control equation in the reservoir matrix of the shale gas reservoir can be constructed based on the model; the construction process is shown in the following steps S31-S33.

[0197] S31. Obtain the property parameters of methane in the shale gas reservoir; in this embodiment, the property parameters of methane can include, but are not limited to, the effective permeability of methane in the shale gas reservoir, the gas viscosity of methane, the gas phase pressure of methane, and the relative permeability of methane, and the above property parameters are all preset parameters.

[0198] After obtaining the property parameters of methane, the gas motion equation of methane can be constructed based on the property parameters, and the process is shown in the following step S32.

[0199] S32. Construct the gas motion equation of methane according to the property parameters; in specific applications, the following formula (20) can be used to construct the above gas motion equation.

[0200] (20)

[0201] In the above formula (20), represents the gas motion equation, which also represents the flow velocity of methane, represents the relative permeability, represents the effective permeability, represents the gas viscosity, represents the gas phase pressure, represents the gradient operator.

[0202] Thus, after the gas motion equation of methane is constructed based on the aforementioned formula (20), the aforementioned first gas-liquid two-phase flow control equation can be constructed in combination with the aforementioned adsorption and desorption model, and the process is shown in the following step S33.

[0203] S33. Construct the first gas-liquid two-phase flow control equation based on the gas motion equation and the adsorption and desorption model; in specific applications, for example, but not limited to, the following formula (21) and formula (22) can be used to construct the first gas-liquid two-phase flow control equation.

[0204] (21)

[0205] (22)

[0206] The aforementioned formula (21) and formula (22) represent the first gas-liquid two-phase flow control equation; wherein in formula (21), in turn represent the flow velocity of water and methane (gas) in the reservoir matrix, in turn represent the relative permeability of water and methane in the reservoir matrix, represents the pore pressure of the reservoir matrix (an unknown quantity), in turn represent the viscosity of water and methane in the reservoir matrix, represents the capillary pressure in the reservoir matrix, in turn represent the effective permeability and apparent permeability of the reservoir matrix.

[0207] In the aforementioned formula (22), in turn represent the density of water and methane in the reservoir matrix, represents the effective porosity of the reservoir matrix, represents the water saturation in the reservoir matrix, in turn represent the exchange flow of water between the reservoir matrix and the hydraulic fracture, and the exchange flow of methane between the reservoir matrix and the hydraulic fracture (the calculation process of the two is described in detail in the following step S4), is the methane adsorption amount, and t represents time.

[0208] wherein, in the formula, represents the rock density of the reservoir.

[0209] Thus, through the aforementioned steps S31-S33, the gas-liquid two-phase flow control equation in the reservoir matrix can be constructed, and then the aforementioned first hydraulic fracture extension data can be combined to establish a horizontal well production seepage model, so as to predict the pore pressure distribution data of the reservoir in the shale gas reservoir based on the horizontal well production seepage model; wherein the construction process of the horizontal well production seepage model is shown in the following step S4.

[0210] S4. Based on the first gas-liquid two-phase flow control equation and the first hydraulic fracture extension data, a horizontal well production seepage model is established, and based on the horizontal well production seepage model, pore pressure distribution data of the reservoir in the shale gas reservoir is predicted; in specific application, this embodiment also needs to construct a second gas-liquid two-phase flow control equation in the hydraulic fracture, and then, combined with the first hydraulic fracture extension data obtained in the foregoing step S2, a horizontal well production seepage model is constructed, wherein the construction process of the foregoing horizontal well production seepage model can be but is not limited to the following steps S41-S44.

[0211] S41. Obtain the reservoir matrix permeability; in this embodiment, the foregoing reservoir matrix permeability is a preset parameter, which can be read in use; and after the foregoing data is obtained, the exchange coefficient between the hydraulic fracture and the reservoir matrix can be calculated in combination with the first hydraulic fracture extension data, and the process is shown in the following step S42.

[0212] S42. According to the first hydraulic fracture extension data and the reservoir matrix permeability, the exchange coefficient between the hydraulic fracture and the reservoir matrix is calculated; in specific application, the exchange coefficient is calculated based on the foregoing data and through an embedded discrete fracture model; the formula is wherein, the exchange coefficient between the hydraulic fracture and the reservoir matrix is multiplied by the pressure difference to calculate the exchange flow of methane and water between the hydraulic fracture and the reservoir matrix in step S43, the reservoir matrix permeability is represented by, the fracture length in the first hydraulic fracture extension data is represented by h, and h represents the reservoir thickness (preset value), the equivalent normal distance between the fracture trajectory in the first hydraulic fracture extension data and the reservoir matrix is represented by, and of course, the embedded discrete fracture model is a common way to calculate the exchange coefficient between the fracture and the reservoir matrix, and the calculation process is not described again.

[0213] After the exchange coefficient between the hydraulic fracture and the reservoir matrix is obtained, the construction of the gas-liquid two-phase flow control equation in the hydraulic fracture can be performed, and the process is shown in the following step S43.

[0214] S43. According to the exchange coefficient, a second gas-liquid two-phase flow control equation in the hydraulic fracture is constructed; in this embodiment, for example, but not limited to, the following formula (23) is used to construct the foregoing second gas-liquid two-phase flow control equation.

[0215] (23)

[0216] The foregoing formula (23) represents the second gas-liquid two-phase flow control equation, wherein, Let represent the densities of methane and water in the hydraulic fracture, respectively. Indicates the effective porosity of a hydraulic fracture. Indicates the water saturation in the hydraulic fracture. These represent the relative permeabilities of methane and water in the hydraulic fracture, respectively. Indicates the effective permeability of the hydraulic fracture. The following numbers represent the viscosity of methane and water in the hydraulic fracture, respectively. This represents the pressure of the new fluid within the hydraulic fracture (which is different from the pressure calculated in step S2). different), These represent the source terms (i.e., the production of methane and water) of horizontal wells, respectively. These represent the methane exchange flow rate between the hydraulic fracture and the reservoir matrix (i.e., the methane flow rate between the hydraulic fracture and the reservoir matrix), and the water exchange flow rate between the hydraulic fracture and the reservoir matrix (i.e., the water flow rate between the hydraulic fracture and the reservoir matrix), respectively; where, It is based on The calculated flow rate of methane and water is obtained by multiplying the pressure difference between the two.

[0217] After obtaining the second gas-liquid two-phase flow control equation within the hydraulic fracture, the aforementioned first gas-liquid two-phase flow control equation can be combined to construct a horizontal well production seepage model, as shown in step S44 below.

[0218] S44. Using the finite volume method, discretize the first gas-liquid two-phase flow control equation and the second gas-liquid two-phase flow control equation to obtain the horizontal well production seepage model.

[0219] In practical applications, an example of a horizontal well production seepage model is as follows:

[0220] (twenty four)

[0221] Formula (24) represents the production flow model of the horizontal well, where, The first flow coefficient matrix (the flow coefficient matrix between the reservoir matrix and the hydraulic fracture) and the second flow coefficient matrix (the flow coefficient matrix between the hydraulic fracture and the reservoir matrix) are represented sequentially. They are obtained by discretizing the aforementioned two-phase gas-liquid flow control equations using the finite volume method. These represent the third flow coefficient matrix between reservoir matrices and the fourth flow coefficient matrix between hydraulic fractures (which are constant matrices with preset parameters). These represent the reservoir matrix pore pressure matrix and the new fluid pressure matrix of the hydraulic fracture (which are unknowns). respectively represent the reservoir matrix flow source term matrix and the hydraulic fracture flow source term matrix, which can be obtained by the production parameters of the horizontal well (a constant matrix, which can be calculated according to the bottom hole flowing pressure, the methane density under standard conditions, the generation time and other data, and is also pre-calculated and stored in the interwell interference analysis end).

[0222] Therefore, by the foregoing steps S41-S44, the horizontal well production percolation model can be constructed. In this way, the foregoing gas motion equation and the methane adsorption and desorption model describe the cross-scale flow behavior and the analytical adsorption phenomenon of the methane in the shale reservoir, which are combined in the control equation of the first gas-liquid two-phase flow in the reservoir matrix. Then, the control equation of the gas-liquid two-phase flow in the hydraulic fracture is combined, the finite volume method is used to discretize to obtain the numerical calculation expression, and the matrix is iteratively solved to obtain the reservoir matrix pore pressure matrix and the hydraulic fracture new fluid pressure matrix. In this way, the pore pressure distribution data of the reservoir in the shale gas reservoir can be obtained based on the foregoing formula (24).

[0223] After obtaining the pore pressure distribution data of the reservoir in the shale gas reservoir, the pore pressure distribution data can be used to determine the geostress field of the shale reservoir after the horizontal well production, and the process is shown in the following step S5.

[0224] S5. Obtain the initial in-situ stress field of the shale reservoir, and determine the geostress field evolution data of the shale reservoir after the horizontal well production according to the initial in-situ stress field and the pore pressure distribution data. In specific applications, the geostress field evolution data of the shale reservoir after the horizontal well production, that is, the geostress field of the shale reservoir after the horizontal well production, can be obtained by, for example but not limited to, the following steps S51-S55.

[0225] S51. Obtain the rock attribute parameters of the shale reservoir. In this embodiment, the rock attribute parameters can include, for example but not limited to, the Young's modulus, the Poisson's ratio and the reservoir rock skeleton volume modulus of the reservoir rock. In this way, after obtaining the rock attribute parameters, the reservoir stress balance equation can be constructed in combination with the pore pressure distribution data, and the process is shown in the following step S52.

[0226] S52. Construct the reservoir stress balance equation based on the pore pressure change according to the rock attribute parameters and the pore pressure distribution data. In specific implementations, the foregoing reservoir stress balance equation can be constructed by, for example but not limited to, the following formula (25).

[0227] (25)

[0228] In the foregoing formula (25), represents the total stress tensor of the reservoir matrix, represents the Biot coefficient, denotes the reservoir rock bulk modulus, denotes the unit tensor, denotes the pore pressure distribution data, denotes the adsorption strain constant, denotes the adsorption volume of the unit mass medium, denotes the saturated load, b denotes the body force, and can be ignored, wherein, is obtained according to the Young's modulus and the Poisson's ratio of the reservoir rock, and is calculated based on and the reservoir rock skeleton bulk modulus,

[0229] Specifically, , wherein, denote the Young's modulus and the Poisson's ratio of the reservoir rock, respectively, and , wherein, denotes the reservoir rock skeleton bulk modulus.

[0230] Thus, by constructing the reservoir stress balance equation through the aforementioned formula (25), the change value of the reservoir stress caused by the shale gas reservoir horizontal well production can be calculated based on the equation, and the process is shown in the following step S53.

[0231] S53. Solving the reservoir stress balance equation to obtain the change value of the reservoir stress caused by the shale gas reservoir horizontal well production; in the embodiment, the pore pressure distribution data obtained in the aforementioned step S4 is substituted into the aforementioned formula (25), so as to calculate the change value of the reservoir stress caused by the shale gas reservoir horizontal well production, that is, to calculate ; and then, the induced stress field of the hydraulic fracture generated in the reservoir can be obtained, so as to determine the in-situ stress field evolution data of the shale reservoir after the horizontal well production in combination with the initial in-situ stress field of the reservoir matrix.

[0232] Wherein, the process of obtaining the induced stress field is shown in the following step S54.

[0233] S54. Obtain the induced stress field generated by the hydraulic fracture in the reservoir after the shale gas reservoir horizontal well production; in the specific implementation, considering the influence of the closure of the hydraulic fracture in the shale gas reservoir horizontal well production process, for example, but not limited to, based on the trajectory and fracture width of the hydraulic fracture in the first hydraulic fracture extension data, and by the displacement discontinuity method, the relationship between displacement and induced stress is used to calculate the induced stress field generated by the hydraulic fracture in the reservoir after the shale gas reservoir horizontal well production; in this embodiment, according to the hydraulic fracture trajectory and the fracture width, and using the displacement discontinuity method to calculate the induced stress field, it is a common technical method for the hydraulic fracture to induce the stress field, and the process is mainly: first, a mathematical model is established according to the displacement discontinuity method to describe the relationship between the fracture width and the induced stress of the hydraulic fracture, and then the fracture trajectory and the fracture width data are input into the mathematical model to calculate the induced stress field distribution caused by the hydraulic fracture in the reservoir; of course, the foregoing technique is a common calculation method for the induced stress field, and the calculation process will not be described here.

[0234] Therefore, after obtaining the induced stress field, the initial in-situ stress field and the change value of the reservoir stress can be combined to obtain the stress field evolution data, and the process is shown in the following step S55.

[0235] S55. Perform stress superposition processing on the initial in-situ stress field, the change value of the reservoir stress, and the induced stress field to obtain the stress field evolution data after stress superposition processing; in this embodiment, the initial in-situ stress field is the stress of the reservoir matrix when the shale gas reservoir horizontal well is not produced; based on this, the three stresses are superimposed to obtain the stress field evolution data of the shale reservoir after the horizontal well production.

[0236] Therefore, through the foregoing steps S51-S55, the stress field of the shale reservoir after the horizontal well production can be predicted, and then the stress field evolution data can be used as the boundary condition, and the initial in-situ stress field can be used as the boundary condition to respectively perform the extension prediction of the hydraulic fracture in the fractured well, so as to obtain the extension data of the hydraulic fracture in the fractured well before and after the horizontal well production, and the process is shown in the following step S6.

[0237] S6. Respectively taking the in-situ stress field evolution data and the initial in-situ stress field of the shale reservoir as the boundary conditions, and using the horizontal well segmented multi-cluster fracturing fracture propagation model, the second hydraulic fracture extension data and the third hydraulic fracture extension data in the fractured well are obtained; in this embodiment, it is equivalent to recalculating the tangential stress component and the normal stress component, and the four influence coefficient matrices in the aforementioned formula (4) and formula (5) based on the in-situ stress field evolution data; then, the recalculated influence coefficients and the two stress components are substituted into the rock deformation constitutive equation, and combined with the fracturing fluid flow control equation, the fracture width (for easy distinction, named second fracture width) and the fluid pressure of the hydraulic fracture in the fractured well are recalculated; then, based on the fracture width of the hydraulic fracture in the fractured well and the aforementioned formula (16)-(18), the calculation of the fracture extension direction and the fracture length extension step of the hydraulic fracture is re-performed, and thus the fracture length (i.e. the second fracture length) of the hydraulic fracture in the fractured well is obtained; in this way, the fracture width and the fracture length of the hydraulic fracture in the fractured well can be used to form the second hydraulic fracture extension data; similarly, when the initial in-situ stress field is used as the boundary condition, the calculation process of the corresponding third hydraulic fracture extension data is also the same, which will not be described here.

[0238] Based on this, after obtaining the propagation data of the hydraulic fracture in the fractured well before and after the horizontal well production, the interwell interference analysis can be performed based on the two, and the process is shown in the following step S7.

[0239] S7. The second hydraulic fracture extension data and the third hydraulic fracture extension data are used to obtain the interwell interference analysis result; in specific application, the second hydraulic fracture extension data includes the second fracture length and the second fracture width of the fractured well, and the third hydraulic fracture extension data includes the third fracture length and the third fracture width of the fractured well; in this way, the interference analysis can be performed according to the fracture width and fracture length data of the hydraulic fracture in the fractured well before and after the horizontal well production, and the process is shown in the following steps S71-S75.

[0240] S71. Based on the second fracture length and the second fracture width of the fractured well, the first average fracture length, the first average fracture width and the first fracture length variation coefficient are calculated; in this embodiment, for example, but not limited to, the first average fracture length, the second average fracture width and the first fracture length variation coefficient on both sides of the fractured well are calculated; wherein the first fracture length variation coefficient calculation formula is , wherein σ1 represents the first fracture length variation coefficient; σ2 represents the first average fracture length; σ3 represents the standard deviation of the second fracture length.

[0241] Similarly, for the horizontal well after production, the corresponding average fracture length, average fracture width and fracture length variation coefficient are also calculated, and the process is shown in the following step S72.

[0242] S72. According to the third fracture length and the third fracture width of the fractured well, the second average fracture length, the second average fracture width and the second fracture length variation coefficient are calculated; in this embodiment, the calculation process of the second fracture length variation coefficient is the same as the first fracture length variation coefficient, and will not be described here.

[0243] After obtaining the average fracture length, the average fracture width and the fracture length variation coefficient on both sides of the fractured well before and after the horizontal well production, the differences of the hydraulic fracture parameters considering and not considering the influence of the production well can be compared, and the interference degree of the horizontal well production of the shale gas reservoir on the fracturing of the adjacent well is quantitatively evaluated by using the change rate, and the process is shown in the following steps S73-S75.

[0244] S73. The fracture length change rate is obtained based on the first average fracture length and the second average fracture length.

[0245] S74. The fracture width change rate is obtained according to the first average fracture width and the second average fracture width, and the fracture length variation coefficient change rate is obtained based on the first fracture length variation coefficient and the second fracture length variation coefficient; thus, after obtaining the fracture length change rate, the fracture width change rate and the fracture length variation coefficient change rate, the aforementioned three change rates can be used to form the interwell interference analysis result, and the process is shown in the following step S75.

[0246] S75. The interwell interference analysis result is generated by using the fracture length change rate, the fracture width change rate and the fracture length variation coefficient change rate.

[0247] Thus, after obtaining the change rates of the differences of the hydraulic fracture parameters considering and not considering the influence of the production well through the aforementioned steps S71-S75, the interwell interference analysis result can be generated, and then the interwell interference analysis result can be visually displayed to assist the staff in arranging the horizontal well group and optimizing the horizontal well fracturing parameters; further, for example, the well group layout and the horizontal well fracturing parameter database can be set in advance in the interwell interference analysis end, wherein each well group layout and horizontal well fracturing parameter corresponds to a calibrated interwell interference analysis result (i.e. the change rates of the fracture length, the fracture width and the fracture length variation coefficient of the hydraulic fracture in the fractured well before and after the horizontal well production); then, according to the interwell interference analysis result obtained in the aforementioned step S7, data matching is performed in the well group layout and the horizontal well fracturing parameter database, so as to obtain the optimal well group layout information and the optimal horizontal well fracturing parameter corresponding to the interwell interference analysis result; finally, the optimal well group layout information and the optimal horizontal well fracturing parameter are visually displayed to provide guidance for the field horizontal well fracturing construction design and optimization.

[0248] Therefore, through the analysis method for the interference of horizontal well production in shale gas reservoirs on fracturing of adjacent wells, as described in steps S1 to S7 above, this invention considers the influence of natural fractures on hydraulic fracture propagation when predicting hydraulic fracture propagation. Furthermore, when quantifying the impact of pore pressure changes on reservoir stress evolution, it fully considers the combined effects of initial in-situ stress distribution, induced stress field generated by hydraulic fractures, methane adsorption and desorption, and gas-liquid two-phase flow. Therefore, compared to traditional technologies, this invention improves the accuracy of analyzing the interference of horizontal well production on fracturing of adjacent wells, and can provide guidance for the design and optimization of horizontal well fracturing operations.

[0249] In one possible design, the second aspect of this embodiment provides a simulation example of the analysis method described in the first aspect of the embodiment, with the data shown below.

[0250] In this embodiment, the surface density of natural fractures is set to 0.005, the average fracture length is set to 12.0 m, the standard deviation of fracture length is set to 2.0 m, the average azimuth angle of natural fractures is set to 50° and 105°, and the deviation coefficient is set to 200. Statistical methods are used to model natural fractures in the reservoir, as detailed in the following reference. Figure 2 As shown.

[0251] In this embodiment, when simulating multi-cluster fracturing of a horizontal well, a refined short cluster design is considered, simulating 4-stage fracturing with a stage length of approximately 120m. The basic simulation parameters are shown in Table 1.

[0252] Table 1 shows the basic simulation parameters for multi-cluster fracturing in horizontal wells.

[0253] Table 1

[0254]

[0255] Therefore, based on the horizontal well segmented multi-cluster fracturing fracture propagation model constructed in the first aspect of the embodiment, and the basic parameters in Table 1 above, hydraulic fracture propagation simulation can be performed. The simulation results can be found in [reference needed]. Figure 3 As shown, the results of the extension trajectory and width distribution of multiple clusters of fracturing fractures in a horizontal well of a shale reservoir are obtained.

[0256] Then, based on Figure 3 The results of horizontal well segmented multi-cluster fracturing fracture propagation prediction were combined with the horizontal well production seepage model to predict the pore pressure distribution in shale reservoirs under production conditions. Among them, production was carried out by fixing the bottom hole fluid pressure, and the geological parameters, engineering parameters and production parameters required for pore pressure distribution prediction were simulated to obtain the basic simulation parameters of shale gas reservoir horizontal well production as shown in Table 2 below.

[0257] Table 2 shows the basic simulation parameters for production of horizontal wells in shale gas reservoirs.

[0258] Table 2

[0259]

[0260] Based on the data in the aforementioned Table 2, and the horizontal well production percolation model in the first aspect of the embodiment, shale reservoir pore pressure distribution results are simulated and predicted, and the results are shown in Figure 4 From Figure 4 it can be seen that the reservoir pore pressure drop region is mainly concentrated in the hydraulic fracture region, and gradually spreads to the deep region of the hydraulic fracture in the reservoir, and the sweep range of the horizontal well production can be briefly analyzed through the pressure drop region range.

[0261] Then, based on the reservoir stress balance equation in the first aspect of the embodiment and the aforementioned predicted pore pressure distribution, the change value of the reservoir stress caused by the horizontal well production of the gas reservoir is obtained, wherein the change value of the horizontal maximum principal stress is shown in Figure 5 , the change value of the horizontal minimum principal stress is shown in Figure 6 ; further, considering the influence of the closure of the hydraulic fracture in the process of the horizontal well production of the shale gas reservoir, the induced stress field generated by the hydraulic fracture in the reservoir after the horizontal well production is calculated, wherein the induced stress along the horizontal minimum principal stress direction is shown in Figure 7 , the induced stress along the horizontal maximum principal stress direction is shown in Figure 8 ; then, based on the stress superposition principle, the geostress field evolution results of the shale reservoir after the horizontal well production are calculated.

[0262] Finally, taking the stress field evolution results and the initial in-situ stress field as boundary conditions respectively, and using the horizontal well segmented multi-cluster fracturing fracture propagation model established in the first aspect of the embodiment, the extension of the hydraulic fracture in the fracturing well before and after the horizontal well production is predicted; wherein the extension trajectory and the fracture width distribution results of the hydraulic fracture in the fracturing well under the influence of the production well are shown in Figure 9 , and the extension trajectory and the fracture width distribution results of the hydraulic fracture in the fracturing well without considering the influence of the production well are shown in Figure 10 .

[0263] In addition, the average fracture length, the average fracture width, the fracture length coefficient of variation and other parameters on both sides of the fracturing well are calculated based on the aforementioned simulated hydraulic fracture extension data, and the specific reference is shown in Table 3.

[0264] Table 3 is a comparison table of hydraulic fracture geometric parameter indicators considering and not considering the influence of the production well.

[0265] Table 3

[0266]

[0267] As can be seen from Table 3, the production well influences the overall length of the hydraulic fracture, which is reduced by 40.9% compared to the average fracture length without considering the influence of the production well, and the average fracture width is increased by about 45.4%; at the same time, the fracture length coefficient of variation shows that, with the influence of the production well considered, the fracture length on both sides of the horizontal well, i.e. the upper side of the fracturing wellbore far away from the production well and the lower side of the fracturing wellbore close to the production well, is obviously different, while the fracture length on both sides of the fracturing wellbore is less different without considering the influence of the production well; through comparison of the simulation results, the quantified evaluation of the shale gas reservoir horizontal well production interference with the adjacent well fracturing is achieved, which can provide guidance for the design and optimization of the field horizontal well fracturing construction.

[0268] The third aspect of the present embodiment provides a hardware device for implementing the shale gas reservoir horizontal well production interference analysis method described in the first aspect of the present embodiment, comprising:

[0269] A natural fracture modeling unit is configured to establish a natural fracture model of the shale gas reservoir.

[0270] A hydraulic fracture prediction unit is configured to construct a horizontal well segmented multi-cluster fracturing fracture propagation model, and obtain first hydraulic fracture extension data in the horizontal well according to the natural fracture model and the horizontal well segmented multi-cluster fracturing fracture propagation model.

[0271] A pore pressure prediction unit is configured to establish a methane adsorption and desorption model in the shale gas reservoir production process, and construct a first gas-liquid two-phase flow control equation in the reservoir matrix of the shale gas reservoir according to the adsorption and desorption model.

[0272] The pore pressure prediction unit is further configured to establish a horizontal well production seepage flow model based on the first gas-liquid two-phase flow control equation and the first hydraulic fracture extension data, and predict pore pressure distribution data of the shale gas reservoir based on the horizontal well production seepage flow model.

[0273] A geostress field evolution unit is configured to obtain an initial in-situ stress field of the shale reservoir, and determine geostress field evolution data of the shale reservoir after the horizontal well production according to the initial in-situ stress field and the pore pressure distribution data.

[0274] The hydraulic fracture prediction unit is further configured to take the geostress field evolution data of the shale reservoir and the initial in-situ stress field as boundary conditions respectively, and obtain second hydraulic fracture extension data and third hydraulic fracture extension data in the fracturing well by using the horizontal well segmented multi-cluster fracturing fracture propagation model.

[0275] An interwell interference analysis unit is configured to obtain an interwell interference analysis result by using the second hydraulic fracture extension data and the third hydraulic fracture extension data.

[0276] The working process, working details and technical effects of the device provided by the embodiment can be referred to the first aspect of the embodiment, and will not be repeated here.

[0277] The fourth aspect of the embodiment provides another device for analyzing shale gas reservoir horizontal well production interference on adjacent well fracturing. Taking the device as an electronic device, the device comprises a memory, a processor and a transceiver which are sequentially and communicatively connected. The memory is configured to store a computer program. The transceiver is configured to transceive messages. The processor is configured to read the computer program and execute the shale gas reservoir horizontal well production interference analysis method as described in the first aspect of the embodiment.

[0278] The working process, working details and technical effects of the electronic device provided by the embodiment can be referred to the first aspect of the embodiment, and will not be repeated here.

[0279] The fifth aspect of the embodiment provides a storage medium storing instructions of the shale gas reservoir horizontal well production interference analysis method as described in the first aspect of the embodiment. That is, the storage medium stores instructions. When the instructions run on a computer, the shale gas reservoir horizontal well production interference analysis method as described in the first aspect of the embodiment is executed.

[0280] The storage medium refers to a carrier for storing data, which can include, but is not limited to, a floppy disk, an optical disk, a hard disk, a flash memory, a USB flash disk and / or a memory stick, etc. The computer can be a general-purpose computer, a special-purpose computer, a computer network or other programmable devices.

[0281] The working process, working details and technical effects of the storage medium provided by the embodiment can be referred to the first aspect of the embodiment, and will not be repeated here.

[0282] The fifth aspect of the embodiment provides a computer program product containing instructions. When the instructions run on a computer, the computer executes the shale gas reservoir horizontal well production interference analysis method as described in the first aspect of the embodiment. The computer can be a general-purpose computer, a special-purpose computer, a computer network or other programmable devices.

[0283] The above detailed description of the specific embodiments has further described the purposes, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of analyzing shale gas reservoir horizontal well production for interference from offset well fracturing, characterized by, The method comprises the following steps: establishing a natural fracture model of a shale gas reservoir; constructing a horizontal well staged multi-cluster fracturing fracture propagation model, and obtaining first hydraulic fracture extension data in the horizontal well according to the natural fracture model and the horizontal well staged multi-cluster fracturing fracture propagation model; constructing a horizontal well staged multi-cluster fracturing fracture propagation model, comprising: constructing a rock deformation constitutive equation of a hydraulic fracture stress field under the joint action of an in-situ stress and fluid pressure; obtaining construction parameters and completion parameters of the horizontal well; constructing a fracturing fluid flow control equation in the process of fracturing fracture propagation of the horizontal well according to the construction parameters and the completion parameters; using the rock deformation constitutive equation and the fracturing fluid flow control equation to form a hydraulic fracture aperture and fluid pressure prediction model; calculating a hydraulic fracture aperture matrix and a hydraulic fracture fluid pressure matrix based on the hydraulic fracture aperture and fluid pressure prediction model; calculating the energy release rate of each hydraulic fracture tip according to the hydraulic fracture aperture matrix; constructing a hydraulic fracture trajectory prediction model and a fracture propagation length model according to the natural fracture model, the fluid pressure matrix and the energy release rate of each hydraulic fracture tip; using the fracture propagation length model, the trajectory prediction model and the hydraulic fracture aperture and fluid pressure prediction model to form the horizontal well staged multi-cluster fracturing fracture propagation model; establishing a methane adsorption and desorption model in the production process of the shale gas reservoir, and constructing a first gas-liquid two-phase flow control equation in the reservoir matrix of the shale gas reservoir according to the adsorption and desorption model; based on the first gas-liquid two-phase flow control equation and the first hydraulic fracture extension data, establishing a horizontal well production seepage model, and based on the horizontal well production seepage model, predicting the pore pressure distribution data of the reservoir in the shale gas reservoir; obtaining the initial in-situ stress field of the shale reservoir, and determining the geostress field evolution data of the shale reservoir after the production of the horizontal well according to the initial in-situ stress field and the pore pressure distribution data; respectively taking the geostress field evolution data of the shale reservoir and the initial in-situ stress field as boundary conditions, and using the horizontal well staged multi-cluster fracturing fracture propagation model to obtain second hydraulic fracture extension data and third hydraulic fracture extension data in the fractured well; using the second hydraulic fracture extension data and the third hydraulic fracture extension data to obtain the interwell interference analysis result.

2. The method of claim 1, wherein, The method comprises the following steps: obtaining geological parameters of a shale gas reservoir where a horizontal well is located, wherein the geological parameters comprise natural fracture surface density, reservoir area, natural fracture length and natural fracture azimuth angle; constructing a natural fracture number model according to the natural fracture surface density and the reservoir area; constructing a natural fracture length model based on the natural fracture length; constructing a natural fracture azimuth angle model according to the natural fracture azimuth angle; using the natural fracture number model, the natural fracture length model and the natural fracture azimuth angle model to form the natural fracture model.

3. The method of claim 1, wherein, The method comprises the following steps: obtaining normal stress components and tangential stress components acting on the hydraulic fractures, and a first influence coefficient matrix between normal and normal based on fracture height correction, a second influence coefficient matrix between tangential and tangential based on fracture height correction, a third influence coefficient matrix between normal and tangential based on fracture height correction, and a fourth influence coefficient matrix between tangential and normal based on fracture height correction; calculating a comprehensive ground stress matrix acting on the hydraulic fractures according to the normal stress components, the tangential stress components, the third influence coefficient matrix and the second influence coefficient matrix; calculating a comprehensive influence coefficient matrix based on the first influence coefficient matrix, the second influence coefficient matrix, the third influence coefficient matrix and the fourth influence coefficient matrix; constructing the rock deformation constitutive equation based on the hydraulic fracture width and the fluid pressure in the hydraulic fracture by using the comprehensive ground stress matrix and the comprehensive influence coefficient matrix.

4. The method of claim 1, wherein, constructing a fracturing fluid flow control equation in the process of horizontal well fracturing fracture propagation according to construction parameters and completion parameters, including: obtaining a fracturing fluid flow coefficient matrix; calculating horizontal wellbore friction and perforation hole friction of each perforation cluster in the horizontal well according to the construction parameters and the completion parameters; calculating fracturing fluid displacement of each perforation cluster based on the horizontal wellbore friction and the perforation hole friction of each perforation cluster; constructing the fracturing fluid flow control equation based on the hydraulic fracture width and the fluid pressure in the hydraulic fracture by using the fracturing fluid flow coefficient matrix and the fracturing fluid displacement of each perforation cluster.

5. The method of claim 1, wherein, constructing a first gas-liquid two-phase flow control equation in the reservoir matrix of the shale gas reservoir according to the adsorption and desorption model, including: obtaining attribute parameters of methane in the shale gas reservoir; constructing a gas motion equation of methane according to the attribute parameters; constructing the first gas-liquid two-phase flow control equation based on the gas motion equation and the adsorption and desorption model.

6. The method of claim 1, wherein, establishing an adsorption and desorption model of methane in the production process of the shale gas reservoir, including: obtaining gas constants of methane, and saturation load and component adsorption enthalpy variation of methane in the shale gas reservoir; constructing the adsorption and desorption model according to the gas constants, the saturation load and the component adsorption enthalpy variation, and according to the following formula: wherein represents the adsorption-desorption model, represents the saturation load, each represents a constant, represents the component adsorption enthalpy change, represents the gas constant, represents the temperature, represents the heterogeneity constant, represents the gas pressure.

7. The method of claim 1, wherein, establishing a horizontal well production seepage model based on the first gas-liquid two-phase flow control equation and first hydraulic fracture extension data, including: obtaining reservoir matrix permeability; calculating an exchange coefficient between the hydraulic fracture and the reservoir matrix according to the first hydraulic fracture extension data and the reservoir matrix permeability; constructing a second gas-liquid two-phase flow control equation in the hydraulic fracture according to the exchange coefficient; discretizing the first gas-liquid two-phase flow control equation and the second gas-liquid two-phase flow control equation by using the finite volume method to obtain the horizontal well production seepage model.

8. The method of claim 1, wherein, determining the ground stress field evolution data of the shale reservoir after the production of the horizontal well according to the initial in-situ stress field and the pore pressure distribution data, including: obtaining rock attribute parameters of the shale reservoir; constructing a reservoir stress balance equation based on pore pressure change according to the rock attribute parameters and the pore pressure distribution data; solving the reservoir stress equilibrium equation to obtain a change value of reservoir stress caused by shale gas reservoir horizontal well production; obtaining an induced stress field of a hydraulic fracture in the reservoir after shale gas reservoir horizontal well production; performing stress superposition processing on the initial in-situ stress field, the change value of the reservoir stress and the induced stress field to obtain the geostress field evolution data after stress superposition processing.

9. The method of claim 1, wherein, The second hydraulic fracture extension data includes a second fracture length and a second fracture width of the fractured well, and the third hydraulic fracture extension data includes a third fracture length and a third fracture width of the fractured well; The interwell interference analysis result includes: based on the second fracture length and the second fracture width of the fractured well, a first average fracture length, a first average fracture width and a first fracture length variation coefficient are calculated; based on the third fracture length and the third fracture width of the fractured well, a second average fracture length, a second average fracture width and a second fracture length variation coefficient are calculated; based on the first average fracture length and the second average fracture length, a fracture length change rate is obtained; based on the first average fracture width and the second average fracture width, a fracture width change rate is obtained, and based on the first fracture length variation coefficient and the second fracture length variation coefficient, a fracture length variation coefficient change rate is obtained; the interwell interference analysis result is generated by using the fracture length change rate, the fracture width change rate and the fracture length variation coefficient change rate.

Images