Evaluation method and device for artificial fracture parameter optimization of targeted fracture acidizing well

Abstract

The invention discloses an evaluation method and device for parameter optimization of an artificial fracture of a targeted fractured acidized well. The method comprises the following steps: acquiring a simulation value; performing turning prediction on the crack tip of the targeted fracture acidizing well to obtain a turning prediction value; coupling the multi-time simulation value and the steering prediction value with the optimized parameters of the fracturing fluid; and through geological simulation and laboratory verification, the optimization effect of the coupled parameters is evaluated. By means of the method and device, optimization of parameters is effectively completed; after the fracture parameters of the targeted fracture acidizing well are optimized based on the technology, in the actual fracture acidizing process, the productivity, the economic benefit and the fracture success rate of the targeted fracture acidizing well are all facilitated, and the environmental risk is reduced.

Description

Technical Field

[0001] This application relates to the technical field of parameter optimization, for example, to an evaluation method and device for optimizing artificial fracture parameters of a targeted fracturing and acidizing well. Background Art

[0002] Acid fracturing is a process of using acid fluid as the fracturing fluid under a pressure higher than the formation fracture pressure without adding proppants. During acid fracturing, the wall surface of the fracture is corroded into an uneven surface by the corrosion action of the acid fluid. It is an important technical means widely used in carbonate rock oil and gas reservoirs to increase the production of low-permeability oil and gas wells. During acid fracturing, the fracture always extends and expands along the direction of the minimum principal stress. After the acid fracturing operation, the fluid along the length of the fracture continuously converges into the hydraulic fracture and further flows to the bottom hole through the fracture. This method can effectively utilize the fluid in the direction of the horizontal principal stress along the fracture, but in the non-principal stress area far from the fracture, a large amount of oil and gas resources cannot be effectively utilized. Therefore, in order to further utilize the oil and gas resources in the non-principal stress area far from the fracture, the "targeted transformation technology" can be used to form a prefabricated fracture with controllable direction and determined length around the wellbore to achieve artificial fracture diversion, thereby improving the utilization rate of oil and gas resources.

[0003] Currently, the research on the "targeted transformation technology" of fractures in the formation is mostly limited to mechanical analysis. However, in acid fracturing wells, the result of targeted fracturing diversion is not only related to the mechanical factors of fracture propagation in the formation, but also affected by the friction along the wellbore and the pressure loss in the fracture. Moreover, currently, the optimization of fracture parameters for acid fracturing wells is mainly carried out for regular planar regular fractures, and there is no report on the optimization method for targeted acid fracturing fracture parameters.

[0004] Therefore, how to optimize the fracture parameters of targeted acid fracturing wells is one of the urgent problems to be solved in this field. Summary of the Invention

[0005] To have a basic understanding of some aspects of the disclosed embodiments, a simple summary is given below. This summary is not a general review, nor is it intended to identify key / important constituent elements or delineate the protection scope of these embodiments, but rather serves as a preface to the subsequent detailed description.

[0006] On the one hand, the embodiments of the present disclosure provide an evaluation method for optimizing artificial fracture parameters of a targeted fracturing and acidizing well, including:

[0007] Obtaining a simulation value, where the simulation value includes the magnitude and distribution of the pressure received by the fracture of the simulated fracturing and acidizing well;

[0008] Predicting the diversion of the tip of the fracture of the targeted fracturing and acidizing well to obtain a diversion prediction value;

[0009] Couple the multiple simulation values and the steering prediction values with the parameters of the optimized fracturing fluid;

[0010] Evaluate the optimization effect of the coupled parameters through geological simulation and laboratory verification.

[0011] Further, the obtaining of the simulation values includes:

[0012] Geological analysis, analyze the formation structure, lithology, fracture distribution and formation properties to obtain the geological conditions;

[0013] Based on the geological conditions, simulate and calculate the pressure magnitude and pressure distribution on the fractures of the fracturing and acidizing well.

[0014] Further, the obtaining of the optimized fracturing fluid includes:

[0015] Based on the simulated pressure magnitude and pressure distribution, optimize the components of the fracturing fluid and the content of each component.

[0016] Further, the evaluating of the optimization effect of the coupled parameters through geological simulation and laboratory verification includes:

[0017] Conduct numerical simulation on fracture propagation to verify the effectiveness of the optimized parameters;

[0018] Laboratory simulation to test the size and morphology of the fractures.

[0019] Further, the simulation and calculation of the pressure magnitude on the fractures of the fracturing and acidizing well includes:

[0020] Use the correction formula of the regression fitting model for natural logarithm conversion to obtain the friction reduction ratio of the pipe string along the way, where the correction formula is:

[0021]

[0022] In the formula, σ is the friction reduction ratio of the pipe string along the way, D is the diameter of the pipe string; Q is the displacement; M is the mass concentration of the thickening agent;

[0023] Calculate the friction of the pipe string along the way based on the friction reduction ratio method of the pipe string along the way, where the calculation formula is:

[0024]

[0025] In the formula, σ is the friction reduction ratio of the pipe string along the way; Δp0 is the friction of the pipe string along the way of clear water; Δp G,P is the friction of the pipe string along the way of the fracturing fluid;

[0026] Substitute the friction of the pipe string along the way into the calculation formula of the sidewall pressure of the fracturing and acidizing well to obtain the bottom hole pressure, where the calculation formula is:

[0027] p w = p wh + p h - ΔP GP ,

[0028] Wherein, P w is the bottom-hole pressure; p wh is the wellhead pressure; p h is the hydrostatic pressure;

[0029] Substitute the bottom-hole pressure into the vertical fracture unstable seepage pressure calculation model, and after multiple processes, calculate and analyze the pressure in the fracture through Laplace transform.

[0030] Furthermore, the simulation calculates the pressure distribution received by the fracture of the fracturing acidizing well, including:

[0031] Obtain the dimensionless bottom-hole pressure based on relevant parameters and variables, wherein the calculation formula is:

[0032]

[0033] Wherein, p wD is the dimensionless bottom-hole pressure; K is the permeability; h is the reservoir thickness; Δp is the pressure difference; q is the flow rate; μ is the viscosity; B is the volume coefficient;

[0034] Based on Laplace transform, solve to obtain the dimensionless formation pressure, wherein the calculation formula is:

[0035]

[0036] x D 2 + y D 2 = r D 2 ;

[0037] Wherein, u is the Laplace variable; p D is the dimensionless formation pressure; r D is the dimensionless fracture radial length; K0 is the Bessel function; x D is the dimensionless fracture length in the x direction, y D is the dimensionless fracture length in the y direction;

[0038] After superimposing the dimensionless bottom-hole pressure and the dimensionless formation pressure, obtain the pressure distribution of the infinite conductivity vertical fracture in the Laplace space, wherein the pressure distribution is:

[0039]

[0040] Wherein, a is the x coordinate value of any point.

[0041] Further, the steering prediction of the crack tip of the targeted fracturing acidification well to obtain a steering prediction value includes:

[0042] Based on the discontinuous displacement on the crack surface, a stress intensity factor model of the multi-crack body is obtained, where the stress intensity factor model is:

[0043] U x = [2(1 - ν)F3 - yF5]D s + [-(1 - 2ν)F2 - yF4]D n ;

[0044] U y = [2(1 - ν)F2 - yF4]D s + [2(1 - 2ν)F3 - yF5]D n ;

[0045] σ x = 2G(2F4 + yF3 - yF6)D s + 2G(-F5 + yF7)D n ;

[0046] σ y = 2G(-yF6)D s + 2G(-F5 + yF7)D n ;

[0047] τ xy = 2G(-F5 + yF7)D s + 2G(-yF6)D n ;

[0048]

[0049] In the formula, U x is the plane strain in the x direction; U y is the plane strain in the y direction; F2, F3, F4, F5, F6, F7 are the first-order partial derivative with respect to x, the first-order partial derivative with respect to y, the second-order mixed partial derivative with respect to x and y, the second-order mixed partial derivative with respect to y and x, the third-order mixed partial derivative with respect to x, y, y, and the third-order partial derivative with respect to y; σ x , σ y and τ xy are available stresses; ν is the Poisson's ratio; G is the shear modulus; D s is the tangential discontinuous displacement; D n is the normal discontinuous displacement;

[0050] Based on the stress intensity factor model of the uniformly distributed force acting on the crack, the crack tip intensity factor is obtained, where the calculation formula is:

[0051]

[0052]

[0053] Where: K Ι is the corrected type-I crack tip strength factor; K ΙΙ is the corrected type-II crack tip strength factor; f is the correction coefficient; K Ι ' is the initial type-I crack tip strength factor; K' ΙΙ is the initial type-II crack tip strength factor; G is the shear modulus; ν is the Poisson's ratio; D s is the tangential discontinuity displacement; D n is the normal discontinuity displacement, and a is the x-coordinate value of any point.

[0054] Furthermore, the coupling of the multiple simulation values and the steering prediction values with the parameters of the optimized fracturing fluid includes:

[0055] According to the magnitude and distribution of the pressure on the fractures in the fracturing acidizing well, after dimensionlessization, it is substituted into the Laplace space, and the functional relationship between the pressure in the fracture and the fracture length is calculated to obtain the crack tip stress when the fracture expands each time;

[0056] Based on the crack tip stress, it is converted into the tangential discontinuity displacement and the normal discontinuity displacement;

[0057] Based on the tangential discontinuity displacement and the normal discontinuity displacement, the fracture strength factor is obtained;

[0058] Based on the fracture strength factor, it is judged whether the fracture starts to crack or / and turns.

[0059] On the other hand, the present invention provides an evaluation device for optimizing the parameters of the artificial fracture in a targeted fracturing acidizing well, which is used to implement the device for the evaluation method of optimizing the parameters of the artificial fracture in a targeted fracturing acidizing well described in any one of the above.

[0060] The evaluation method and device for optimizing the parameters of the artificial fracture in a targeted fracturing acidizing well provided by the embodiments of the present disclosure can achieve the following technical effects:

[0061] 1. The method for optimizing the fracture parameters of the targeted acid fracturing well provided by the present invention first conducts geological analysis on the carbonate rock oil and gas reservoir, then predicts the magnitude and distribution of the pressure on the fracturing acidizing well based on the geological analysis, thereby optimizing the preparation of the treatment fluid. Then, the steering of the targeted fracturing fracture is predicted, and based on the prediction value, it is coupled with the pressure on the fracturing acidizing well and the pressure loss in the fracture. Repeating the above steps realizes the optimization of the fracture parameters of the targeted fracturing acidizing well. Finally, it is verified through simulation and experiment, effectively completing the optimization of the parameters;

[0062] 2. After optimizing the fracture parameters of the targeted fracturing acidizing well using this method, during the actual fracturing acidizing process, it is beneficial to its productivity, economic benefits, fracturing success rate, and reduction of environmental risks.

[0063] 2.1. In terms of improving productivity: After optimizing the fracture parameters, the permeability of the oil and gas reservoir can be improved more effectively, enhancing the productivity of oil and gas; it can also make the fracture expand more fully, increasing the flow channels of oil and gas and improving the productivity index.

[0064] 2.2. In terms of increasing economic benefits: After optimizing the fracture parameters, the production volume and revenue are relatively increased, improving the exploitation efficiency; moreover, the reasonable parameter selection can maximize the output and reduce the production cost, thereby improving the economic benefits.

[0065] 2.3. In terms of increasing the fracturing success rate: After optimizing the fracture parameters, the propagation path and size of the fracture in the target rock can be controlled more precisely; it helps to ensure that the fracture expands along the designed direction, avoiding unexpected leakage or fracture failure and increasing the fracturing success rate.

[0066] 2.4. In terms of reducing environmental risks: By optimizing the fracture parameters, the unnecessary usage of fracturing fluid can be reduced, reducing the consumption of groundwater resources and the environmental impact on the formation; at the same time, through more precise fracture control, the interference between the fracture and adjacent oil and gas wells can be reduced, reducing the connection risk between the formation and the wellbore.

[0067] Other advantages, objectives, and features of the present invention will be described to some extent subsequently, and to some extent, will be obvious to those skilled in the art based on the study of the following text, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the following content.

[0068] The above general description and the following description are only exemplary and explanatory, and are not used to limit this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] One or more embodiments are exemplarily illustrated by the corresponding drawings. These exemplary illustrations and the drawings do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are shown as similar elements. The drawings do not constitute a scale limitation, and among them:

[0070] Figure 1 is a flowchart of an evaluation method for optimizing the artificial fracture parameters of a targeted fracturing acidizing well provided by an embodiment of the present disclosure;

[0071] Figure 2 is a schematic structural diagram of an evaluation device for optimizing the artificial fracture parameters of a targeted fracturing acidizing well provided by an embodiment of the present disclosure. Detailed Implementation Modes

[0072] In order to more comprehensively understand the features and technical content of the embodiments of the present disclosure, the implementation of the embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are only for reference and explanation, and are not used to limit the embodiments of the present disclosure. In the following technical description, for the sake of explanation, numerous details are provided to give a thorough understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be shown in a simplified manner to simplify the drawings.

[0073] In the specification and claims of the embodiments of the present disclosure and the above-mentioned accompanying drawings, terms such as "first", "second", etc. are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so as to implement the embodiments of the present disclosure described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion.

[0074] In the embodiments of the present disclosure, the orientation or positional relationship indicated by terms such as "upper", "lower", "inner", "middle", "outer", "front", "rear", etc. is based on the orientation or positional relationship shown in the accompanying drawings. These terms are mainly used to better describe the embodiments of the present disclosure and their implementations, and are not used to limit that the indicated devices, elements, or components must have a specific orientation or be constructed and operated in a specific orientation. And, in addition to being able to represent an orientation or positional relationship, some of the above terms may also be used to represent other meanings. For example, the term "upper" may also be used to represent a certain attachment relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0075] In addition, the terms "arranged", "connected", "fixed" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or there can be internal communication between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0076] Unless otherwise specified, the term "plurality" means two or more.

[0077] In the embodiments of the present disclosure, the character " / " indicates that the objects before and after are in an "or" relationship. For example, A / B means: A or B.

[0078] The term "and / or" describes the associated relationship of objects, indicating that there can be three relationships. For example, A and / or B means: A or B, or, the three relationships of A and B.

[0079] It should be noted that, without conflict, the embodiments in the present disclosure and the features in the embodiments can be combined with each other.

[0080] Combination Figure 1 As shown, the embodiments of the present disclosure provide an evaluation method for optimizing the artificial fracture parameters of a targeted fracturing and acidizing well, including:

[0081] Obtain simulation values, where the simulation values include the magnitude and distribution of the pressure received by the fractures of the fracturing and acidizing well through simulation calculation;

[0082] Predict the deflection of the fracture tip of the targeted fracturing and acidizing well to obtain a deflection prediction value;

[0083] Couple multiple times of the simulation values and the deflection prediction value with the parameters of the optimized fracturing fluid;

[0084] Evaluate the optimization effect of the coupled parameters through geological simulation and laboratory verification.

[0085] In some embodiments of the present invention, the obtaining of the simulation values includes:

[0086] Geological analysis, analyze the formation structure, lithology, fracture distribution and rock layer properties to obtain the geological conditions;

[0087] Based on the geological conditions, simulate and calculate the magnitude and distribution of the pressure received by the fractures of the fracturing and acidizing well.

[0088] For example, an evaluation method for optimizing the artificial fracture parameters of a targeted fracturing and acidizing well includes the following steps:

[0089] S1. Geological analysis, analyze the formation structure, lithology, fracture distribution and rock layer properties;

[0090] S2. Based on the geological conditions obtained in step S1, simulate and calculate the magnitude and distribution of the pressure received by the fractures of the fracturing and acidizing well;

[0091] S3. Based on the magnitude and distribution of the pressure simulated and calculated in step S2, optimize the components of the fracturing fluid and the content of each component;

[0092] S4. Predict the deflection of the fracture tip of the targeted fracturing and acidizing well;

[0093] S5. Return the simulation values in step S2 and the prediction values in step S4 to the parameters of the fracturing fluid in step S3 for coupling; repeat steps S2 to S4 in this way;

[0094] S6. Simulation and experimental verification: Evaluate the effectiveness of the optimization results through geological simulation and laboratory verification. Numerically simulate the fracture propagation using simulation software to verify the effectiveness of the optimized parameters, and conduct laboratory simulations to test the size and morphology of the fractures.

[0095] In some embodiments of the present invention, in S1, the methods of geological analysis include one or more of core analysis, seismic exploration, electric logging, drilling records and logging data, gravity and magnetic measurements.

[0096] Among them, core analysis obtains information about the formation composition, pore structure, toughness and strength by testing and analyzing the physical, chemical and rock mechanical properties of core samples, so as to determine the fracturability of the formation and the crack resistance of the rock.

[0097] Seismic exploration uses the propagation and reflection of seismic waves underground to obtain information about the formation structure, thickness and properties, so as to obtain a three-dimensional image of the formation structure for identifying potential fractures and faults.

[0098] Electric logging measures electrical properties in the well, including resistivity, natural gamma radiation, density and acoustic velocity, to identify lithology, porosity and permeability, and to determine the distribution and properties of fractures.

[0099] Drilling records and logging data analysis of drilling records and logging data, including logging curves, mud logging data and logging charts, to understand the characteristics, lithology and fluid conditions of the formation, and to obtain information about the well section thickness, pay zone distribution and lithology changes.

[0100] Gravity and magnetic measurements infer the density and magnetic characteristics of underground rocks by measuring the changes in surface gravity and magnetic fields, and are used to identify the thickness of sedimentary rock layers, the location of faults and possible fracture systems.

[0101] In some embodiments of the present invention, in S3, the fracturing fluid includes a liquid phase, a solid phase, additives or auxiliaries; and corresponding fracturing fluid components and the content of each component are selected according to different formation characteristics to increase the liquid viscosity and the carrying capacity of the liquid in the formation, and a suitable pH value is selected according to the formation acidity.

[0102] In some embodiments of the present invention, the acquisition of the optimized fracturing fluid includes:

[0103] Based on the calculated pressure magnitude and pressure distribution, optimize the fracturing fluid components and the content of each component.

[0104] In some embodiments of the present invention, the evaluation of the optimization effect of the coupled parameters through geological simulation and laboratory verification includes:

[0105] Numerically simulate the crack propagation to verify the effectiveness of the optimized parameters;

[0106] Conduct laboratory simulations to test the size and shape of the cracks.

[0107] In some embodiments of the present invention, calculating the pressure on the cracks in the fracturing acidizing well by simulation includes:

[0108] Perform natural logarithm transformation using the correction formula of the regression fitting model to obtain the friction reduction ratio of the pipe string along the way, where the correction formula is:

[0109]

[0110] In the formula, σ is the friction reduction ratio of the pipe string along the way, D is the diameter of the pipe string; Q is the displacement; M is the mass concentration of the thickening agent;

[0111] Calculate the friction of the pipe string along the way based on the friction reduction ratio method of the pipe string along the way, where the calculation formula is:

[0112]

[0113] In the formula, σ is the friction reduction ratio of the pipe string along the way; Δp0 is the friction of the pipe string along the way of clear water; Δp G,P is the friction of the pipe string along the way of the fracturing fluid;

[0114] Substitute the friction of the pipe string along the way into the calculation formula of the sidewall pressure of the fracturing acidizing well to obtain the bottom hole pressure, where the calculation formula is:

[0115] p w = p wh + p h - ΔP GP ,

[0116] In the formula, P w is the bottom hole pressure; p wh is the wellhead pressure; p h is the liquid column pressure;

[0117] Substitute the bottom hole pressure into the vertical fracture unstable seepage pressure calculation model, and after multiple treatments, calculate and analyze the pressure in the fracture through Laplace transform.

[0118] For example, during the fracturing acidizing process, due to the friction and impact of the fluid particles, the viscosity shown by the particle friction and the inertia shown by the change in the flow velocity caused by the particle impact are the fundamental reasons for the generation of the friction along the way; secondly, due to the restriction of the pipe wall, the liquid flow contacts the pipe wall, resulting in friction and impact, consuming energy to form resistance; use the friction reduction ratio method to calculate the friction of the pipe string along the way:

[0119]

[0120] Where: σ is the resistance reduction ratio; Δp0 is the frictional resistance along the pipe string of clear water, Pa; Δp G,P is the frictional resistance along the pipe string of fracturing fluid, Pa;

[0121] Using the correction formula of the regression fitting formula:

[0122]

[0123] Where, D is the diameter of the pipe string, m; Q is the displacement, m 3 / min; M is the mass concentration of the thickening agent, kg / m 3 ;

[0124] Perform natural logarithm transformation on Equation (2) to obtain the resistance reduction ratio of the frictional resistance along the pipe string, and then obtain according to the sidewall pressure calculation formula of the fracturing and acidizing well:

[0125] p w = p wh + p h - Δp G,P (3)

[0126] Where: p w is the bottom hole pressure, MPa; p wh is the wellhead pressure, MPa; p h is the liquid column pressure, MPa;

[0127] Substitute the calculation result of p w into the vertical fracture unstable seepage pressure calculation model, perform dimensionless treatment, and calculate and analyze the pressure in the fracture through Laplace transform.

[0128] In some embodiments of the present invention, the simulation calculation of the pressure distribution received by the fracture of the fracturing and acidizing well includes:

[0129] Based on relevant parameters and variables, obtain the dimensionless bottom hole pressure, where the calculation formula is:

[0130]

[0131] Where, p wD is the dimensionless bottom hole pressure; K is the permeability; h is the reservoir thickness; Δp is the pressure difference; q is the flow rate; μ is the viscosity; B is the volume coefficient;

[0132] Based on Laplace transform, solve to obtain the dimensionless formation pressure, where the calculation formula is:

[0133]

[0134] x D 2+y D 2 = r D 2 ;

[0135] where u is the Laplace variable; p D is the dimensionless formation pressure; r D is the dimensionless fracture radial length; K0 is the Bessel function; x D is the dimensionless fracture length in the x direction, y D is the dimensionless fracture length in the y direction;

[0136] By superimposing the dimensionless bottom-hole pressure and the dimensionless formation pressure, the pressure distribution of an infinitely conductive vertical fracture in the Laplace space is obtained, where the pressure distribution is:

[0137]

[0138] where a is the x coordinate value of any point.

[0139] For example, since the pressure in the fracture during the fracturing process is not constant, its pressure distribution is related to the flow of the fluid in the fracture. Fracturing starts from the rupture of the wellbore wall induced by high-pressure fluid, but the final effect of fracturing mainly depends on the subsequent fracture propagation process. Based on this, the flow of the fluid inside the fracture is assumed to be one-dimensional flow. Assuming that the upper and lower boundaries of the reservoir are impermeable, the fracture is symmetric with the fracture acidizing well, the fracture width is not considered, the effects of capillary pressure and gravity are ignored, and the fracturing fluid is a slightly compressible single-phase fluid, a mathematical model is established and dimensionless quantities are introduced:

[0140]

[0141] where: p wD is the dimensionless bottom-hole pressure; K is the permeability; h is the reservoir thickness; Δp is the pressure difference; q is the flow rate; μ is the viscosity; B is the volume coefficient;

[0142] Solving using the Laplace transform method, we get:

[0143]

[0144] x D 2 +y D 2 = r D 2 (6)

[0145] where: u is the Laplace variable; p D is the dimensionless formation pressure; r D is the dimensionless fracture radial length; K0 is the Bessel function; x Dis the dimensionless crack length in the x direction, y D is the dimensionless crack length in the y direction;

[0146] Through the principle of pressure superposition, the pressure distribution expression of an infinitely conductive vertical crack in the Laplace space is obtained:

[0147]

[0148] In some embodiments of the present invention, the steering prediction of the crack tip of the targeted fracturing and acidizing well to obtain a steering prediction value includes:

[0149] Based on the discontinuous displacement on the crack surface, a stress intensity factor model of a multi-crack body is obtained, where the stress intensity factor model is:

[0150] U x = [2(1 - ν)F3 - yF5]D s + [-(1 - 2ν)F2 - yF4]D n ;

[0151] U y = [2(1 - ν)F2 - yF4]D s + [2(1 - 2ν)F3 - yF5]D n ;

[0152] σ x = 2G(2F4 + yF3 - yF6)D s + 2G(-F5 + yF7)D n ;

[0153] σ y = 2G(-yF6)D s + 2G(-F5 + yF7)D n ;

[0154] τ xy = 2G(-F5 + yF7)D s + 2G(-yF6)D n ;

[0155]

[0156] In the formula, U x is the plane strain in the x direction; U y is the plane strain in the y direction; F2, F3, F4, F5, F6, F7 are the first-order partial derivatives of x, the first-order partial derivatives of y, the second-order mixed partial derivatives of x and y, the second-order mixed partial derivatives of y and x, the third-order mixed partial derivatives of x, y, y, and the third-order partial derivatives of y; σ x , σ y and τxy is the available stress; ν is the Poisson's ratio; G is the shear modulus; D s is the tangential discontinuous displacement; D n is the normal discontinuous displacement;

[0157] Based on the stress intensity factor model of the uniformly distributed force acting on the crack, the crack tip intensity factor is obtained. Among them, the calculation formula is:

[0158]

[0159]

[0160] In the formula, K Ι is the corrected mode I crack tip intensity factor; K ΙΙ is the corrected mode II crack tip intensity factor; f is the correction coefficient; K Ι ' is the initial mode I crack tip intensity factor; K' ΙΙ is the initial mode II crack tip intensity factor; G is the shear modulus; ν is the Poisson's ratio; D s is the tangential discontinuous displacement; D n is the normal discontinuous displacement, and a is the x - coordinate value of any point.

[0161] For example, the method for predicting the turning of the crack tip is:

[0162] Using the displacement discontinuity method, it is assumed that only the pressure in the crack generates singularity at the crack tip, and the external stress field does not directly affect the stress intensity factor, but only affects the stress intensity factor by changing the virtual force in the crack;

[0163] From the stress intensity factor formula of the uniformly distributed force acting on the crack, the expressions of the crack tip intensity factors KI and KII can be obtained as:

[0164]

[0165]

[0166] In the formula: K Ι is the corrected mode I crack tip intensity factor; K ΙΙ is the corrected mode II crack tip intensity factor; f is the correction coefficient; K Ι ' is the initial mode I crack tip intensity factor; K' ΙΙ is the initial mode II crack tip intensity factor; G is the shear modulus; ν is the Poisson's ratio; D s is the tangential discontinuous displacement; D n is the normal discontinuous displacement.

[0167] U x = [2(1 - ν)F3 - yF5]D s + [-(1 - 2ν)F2 - yF4]Dn (10)

[0168] U y = [2(1 - ν)F2 - yF4]D s + [2(1 - 2ν)F3 - yF5]D n (11)

[0169] σ x = 2G(2F4 + yF3 - yF6)D s + 2G(-F5 + yF7)D n (12)

[0170] σ y = 2G(-yF6)D s + 2G(-F5 + yF7)D n (13)

[0171] τ xy = 2G(-F5 + yF7)D s + 2G(-yF6)D n (14)

[0172]

[0173] Where: U x is the plane strain in the x - direction; U y is the plane strain in the y - direction; F2, F3, F4, F5, F6, F7 are the first - order partial derivatives of the function with respect to x, the first - order partial derivatives with respect to y, the second - order mixed partial derivatives with respect to x and y, the second - order mixed partial derivatives with respect to y and x, the third - order mixed partial derivatives with respect to x, y, y, and the third - order partial derivatives with respect to y; σ x , σ y and τ xy are the available stresses; ν is the Poisson's ratio; G is the shear modulus; D s is the tangential discontinuous displacement; D n is the normal discontinuous displacement;

[0174] Solve the above equations (10) - (15) to obtain the discontinuous displacements {D} of each element; at the same time, since the external stress field does not directly affect the stress intensity factor of the multi - crack body, the stress intensity factor of the multi - crack body can be obtained by using the solved discontinuous displacement D on the crack surface.

[0175] In some embodiments of the present invention, in S6, the accuracy of the indoor physical simulation parameters is adopted; the experimental verification method is: the accuracy test of the finite element simulation, and on the basis of the physical simulation test verification, the extended finite element is used for fluid - solid coupling calculation.

[0176] In some embodiments of the present invention, the coupling of the multiple simulation values and the steering prediction values with the parameters of the optimized fracturing fluid includes:

[0177] According to the magnitude and distribution of the pressure on the fracture of the fracturing and acidizing well, after dimensionlessization, it is substituted into the Laplace space, and the functional relationship between the pressure in the fracture and the fracture length is calculated to obtain the crack tip stress at each crack extension.

[0178] Based on the crack tip stress, it is converted into tangential discontinuous displacement and normal discontinuous displacement.

[0179] Based on the tangential discontinuous displacement and the normal discontinuous displacement, the fracture strength factor is obtained.

[0180] Based on the fracture strength factor, it is determined whether the fracture initiates and / or turns.

[0181] Combined body Figure 2 As shown, the embodiment of the present disclosure provides an evaluation device for optimizing the parameters of the artificial fracture of a targeted fracturing and acidizing well, including:

[0182] An acquisition module for acquiring simulation values, where the simulation values include the magnitude and distribution of the pressure on the fracture of the simulated fracturing and acidizing well;

[0183] A prediction module for predicting the steering of the crack tip of the targeted fracturing and acidizing well to obtain a steering prediction value;

[0184] A coupling module for coupling the multiple simulation values and the steering prediction values with the parameters of the optimized fracturing fluid;

[0185] An evaluation module for evaluating the optimization effect of the coupled parameters through geological simulation and laboratory verification.

[0186] In some embodiments of the present invention, the acquisition of the simulation values includes:

[0187] An analysis module for geological analysis, analyzing the formation structure, lithology, fracture distribution and rock formation properties to obtain the geological conditions;

[0188] A calculation module for simulating and calculating the magnitude and distribution of the pressure on the fracture of the fracturing and acidizing well based on the geological conditions.

[0189] In some embodiments of the present invention, the acquisition of the optimized fracturing fluid includes:

[0190] An optimization module for optimizing the components of the fracturing fluid and the content of each component based on the simulated magnitude and distribution of the pressure.

[0191] In some embodiments of the present invention, evaluating the optimization effect of the parameters after coupling through geological simulation and laboratory verification includes:

[0192] A verification module for numerically simulating crack propagation to verify the effectiveness of the optimized parameters;

[0193] A testing module for laboratory simulation to test the size and shape of the cracks.

[0194] In some embodiments of the present invention, simulating and calculating the pressure on the cracks in a fracturing and acidizing well includes:

[0195] Performing natural logarithm transformation using the correction formula of the regression fitting model to obtain the friction reduction ratio of the pipe string along the way, where the correction formula is:

[0196]

[0197] In the formula, σ is the friction reduction ratio of the pipe string along the way, D is the diameter of the pipe string; Q is the displacement; M is the mass concentration of the thickening agent;

[0198] Calculating the friction of the pipe string along the way based on the friction reduction ratio method of the pipe string along the way, where the calculation formula is:

[0199]

[0200] In the formula, σ is the friction reduction ratio of the pipe string along the way, Δp0 is the friction of the pipe string along the way of clear water, and Δp G,P is the friction of the pipe string along the way of the fracturing fluid;

[0201] Substituting the friction of the pipe string along the way into the calculation formula of the sidewall pressure of the fracturing and acidizing well to obtain the bottom hole pressure, where the calculation formula is:

[0202] p w = p wh + p h - ΔP GP ,

[0203] In the formula, P w is the bottom hole pressure, p wh is the wellhead pressure, and p h is the liquid column pressure;

[0204] Substituting the bottom hole pressure into the vertical crack unstable seepage pressure calculation model, after multiple processes, calculating and analyzing the pressure in the crack through Laplace transform.

[0205] For example, during the process of fracturing acidification, due to the friction and impact of particles in the fluid flow, the viscosity manifested by particle friction and the inertia manifested by the change in flow velocity caused by particle impact are the fundamental reasons for the formation of frictional resistance along the way; secondly, due to the limitation of the pipe wall, the liquid flow contacts the pipe wall, resulting in friction and impact, consuming energy to form resistance; the method of using the resistance reduction ratio is adopted to calculate the frictional resistance along the pipe string:

[0206]

[0207] In the formula: σ is the resistance reduction ratio; Δp0 is the frictional resistance along the pipe string of clear water, Pa; Δp G,P is the frictional resistance along the pipe string of fracturing fluid, Pa;

[0208] Using the correction formula of the regression fitting formula:

[0209]

[0210] In the formula, D is the diameter of the pipe string, m; Q is the displacement, m 3 / min; M is the mass concentration of the thickening agent, kg / m 3 ;

[0211] Perform natural logarithm conversion on Equation (2) to obtain the resistance reduction ratio of the frictional resistance along the pipe string, and then obtain according to the calculation formula of the sidewall pressure of the fracturing acidification well:

[0212] p w =p wh +p h -Δp G,P (3)

[0213] In the formula: p w is the bottom hole pressure, MPa; p wh is the wellhead pressure, MPa; p h is the liquid column pressure, MPa;

[0214] Substitute the calculation result of p w into the calculation model of the unstable seepage pressure of the vertical fracture, and after dimensionless treatment, calculate and analyze the pressure in the fracture through Laplace transform.

[0215] In some embodiments of the present invention, the simulation calculation of the pressure distribution received by the fracture of the fracturing acidification well includes:

[0216] Based on relevant parameters and variables, obtain the dimensionless bottom hole pressure, where the calculation formula is:

[0217]

[0218] In the formula, p wDis the dimensionless bottom-hole pressure; K is the permeability; h is the reservoir thickness; Δp is the pressure difference; q is the flow rate; μ is the viscosity; B is the volume coefficient;

[0219] Based on the Laplace transform, the dimensionless formation pressure is solved, and the calculation formula is:

[0220]

[0221] x D 2 +y D 2 =r D 2 ;

[0222] In the formula, u is the Laplace variable; p D is the dimensionless formation pressure; r D is the dimensionless fracture radial length; K0 is the Bessel function; x D is the dimensionless fracture length in the x direction, y D is the dimensionless fracture length in the y direction;

[0223] By superimposing the dimensionless bottom-hole pressure and the dimensionless formation pressure, the pressure distribution of an infinitely conductive vertical fracture in the Laplace space is obtained. The pressure distribution is:

[0224]

[0225] For example, since the pressure in the fracture during the fracturing process is not a constant, its pressure distribution is related to the flow of the fluid in the fracture. Fracturing starts from the fracture of the wellbore wall induced by high-pressure fluid, but the final effect of fracturing mainly depends on the subsequent fracture propagation process. Based on this, the flow of the fluid inside the fracture is set as one-dimensional flow. Assuming that the upper and lower parts of the reservoir are impermeable boundaries, the fracture is symmetrical with the fracture acidizing well, the fracture width is not considered, the capillary pressure and the influence of gravity are ignored, and the fracturing fluid is a slightly compressible single-phase fluid. A mathematical model is established and dimensionless quantities are introduced:

[0226]

[0227] In the formula: p wD is the dimensionless bottom-hole pressure; K is the permeability; h is the reservoir thickness; Δp is the pressure difference; q is the flow rate; μ is the viscosity; B is the volume coefficient;

[0228] Using the Laplace transform method to solve, we get:

[0229]

[0230] x D 2 +y D2 = r D 2 (6)

[0231] where: u is the Laplace variable; p D is the dimensionless formation pressure; r D is the dimensionless fracture radial length; K0 is the Bessel function; x D is the dimensionless fracture length in the x direction, y D is the dimensionless fracture length in the y direction;

[0232] Through the principle of pressure superposition, the pressure distribution expression of an infinitely conductive vertical fracture in Laplace space is obtained:

[0233]

[0234] In some embodiments of the present invention, the steering prediction of the fracture tip of the targeted fracturing and acidizing well to obtain a steering prediction value includes:

[0235] Based on the discontinuous displacement on the crack surface, a stress intensity factor model of a multi-crack body is obtained, where the stress intensity factor model is:

[0236] U x = [2(1 - ν)F3 - yF5]D s + [-(1 - 2ν)F2 - yF4]D n ;

[0237] U y = [2(1 - ν)F2 - yF4]D s + [2(1 - 2ν)F3 - yF5]D n ;

[0238] σ x = 2G(2F4 + yF3 - yF6)D s + 2G(-F5 + yF7)D n ;

[0239] σ y = 2G(-yF6)D s + 2G(-F5 + yF7)D n ;

[0240] τ xy = 2G(-F5 + yF7)D s + 2G(-yF6)D n ;

[0241]

[0242] where, U xis the plane strain in the x direction; U y is the plane strain in the y direction; F2, F3, F4, F5, F6, F7 are the first-order partial derivative of the function with respect to x, the first-order partial derivative with respect to y, the second-order mixed partial derivative with respect to x and y, the second-order mixed partial derivative with respect to y and x, the third-order mixed partial derivative with respect to x, y, y, and the third-order partial derivative with respect to y; σ x , σ y and τ xy are the available stresses; ν is the Poisson's ratio; G is the shear modulus; D s is the tangential discontinuous displacement; D n is the normal discontinuous displacement;

[0243] Based on the stress intensity factor model of the uniformly distributed force acting on the crack, the crack tip intensity factor is obtained. The calculation formula is as follows:

[0244]

[0245]

[0246] In the formula, K Ι is the corrected mode I crack tip intensity factor; K ΙΙ is the corrected mode II crack tip intensity factor; f is the correction coefficient; K Ι ' is the initial mode I crack tip intensity factor; K' ΙΙ is the initial mode II crack tip intensity factor; G is the shear modulus; ν is the Poisson's ratio; D s is the tangential discontinuous displacement; D n is the normal discontinuous displacement.

[0247] For example, the method for predicting the turning of the crack tip is as follows:

[0248] Using the displacement discontinuity method, it is assumed that only the pressure in the crack produces singularity at the crack tip, and the external stress field does not directly affect the stress intensity factor, but only affects the stress intensity factor by changing the virtual force in the crack;

[0249] From the stress intensity factor formula of the uniformly distributed force acting on the crack, the expressions of the crack tip intensity factors KI and KII can be obtained as follows:

[0250]

[0251]

[0252] In the formula: K Ι is the corrected mode I crack tip intensity factor; K ΙΙ is the corrected mode II crack tip intensity factor; f is the correction coefficient; K Ι ' is the initial mode I crack tip intensity factor; K' ΙΙis the type-II initial crack-tip strength factor; G is the shear modulus; ν is the Poisson's ratio; D s is the tangential discontinuity displacement; D n is the normal discontinuity displacement.

[0253] U x = [2(1 - ν)F3 - yF5]D s + [-(1 - 2ν)F2 - yF4]D n (10)

[0254] U y = [2(1 - ν)F2 - yF4]D s + [2(1 - 2ν)F3 - yF5]D n (11)

[0255] σ x = 2G(2F4 + yF3 - yF6)D s + 2G(-F5 + yF7)D n (12)

[0256] σ y = 2G(-yF6)D s + 2G(-F5 + yF7)D n (13)

[0257] τ xy = 2G(-F5 + yF7)D s + 2G(-yF6)D n (14)

[0258]

[0259] Where: U x is the plane strain in the x direction; U y is the plane strain in the y direction; F2, F3, F4, F5, F6, F7 are the first-order partial derivatives with respect to x, the first-order partial derivatives with respect to y, the second-order mixed partial derivatives with respect to x and y, the second-order mixed partial derivatives with respect to y and x, the third-order mixed partial derivatives with respect to x, y, y, and the third-order partial derivatives with respect to y; σ x , σ y and τ xy are the available stresses; ν is the Poisson's ratio; G is the shear modulus; D s is the tangential discontinuity displacement; D n is the normal discontinuity displacement;

[0260] Solve the above equations (10) to (15) to obtain the discontinuity displacements {D} of each element; at the same time, since the external stress field does not directly affect the stress intensity factors of the multi-crack body, the stress intensity factors of the multi-crack body can be obtained using the solved discontinuity displacement D on the crack surface.

[0261] In some embodiments of the present invention, in S6, the accuracy of indoor physical simulation parameters is adopted; the experimental verification method is: finite element simulation accuracy test, and on the basis of physical simulation test verification, extended finite element is used for fluid-structure interaction calculation.

[0262] In some embodiments of the present invention, the coupling of multiple simulation values and the steering prediction values with the parameters of the optimized fracturing fluid includes:

[0263] A first calculation module, configured to non-dimensionalize according to the magnitude and distribution of the pressure received by the fracture of the fracturing and acidizing well, and substitute it into the Laplace space to calculate the functional relationship between the pressure in the fracture and the fracture length, and obtain the crack tip stress when the fracture expands each time;

[0264] A conversion module, configured to convert into tangential discontinuous displacement and normal discontinuous displacement based on the crack tip stress;

[0265] A second calculation module, configured to obtain a fracture strength factor based on the tangential discontinuous displacement and the normal discontinuous displacement;

[0266] A judgment module, configured to judge whether the fracture starts to crack or / and turn based on the fracture strength factor.

[0267] Through the method and device, the following technical effects are achieved:

[0268] The method for optimizing the parameters of the targeted acid fracturing well fracture provided by the present invention first conducts geological analysis on the carbonate rock oil and gas reservoir, then predicts the magnitude and distribution of the pressure received by the fracturing and acidizing well based on the geological analysis, and optimizes the preparation of the reforming liquid accordingly. Then, it predicts the steering of the targeted fracturing fracture, and couples based on the prediction value with the pressure received by the fracturing and acidizing well and the pressure loss in the fracture. Repeating the above steps realizes the optimization of the parameters of the targeted fracturing and acidizing well fracture. Finally, it is verified through simulation and experiment, effectively completing the optimization of the parameters;

[0269] After optimizing the parameters of the targeted fracturing and acidizing well fracture by using this method, during the actual fracturing and acidizing process, it is beneficial to its productivity, economic benefits, fracturing success rate and reducing environmental risks:

[0270] In terms of improving productivity: After optimizing the fracture parameters, it can more effectively improve the permeability of the oil and gas reservoir, enhance the productivity of oil and gas; it can also make the fracture expand more fully, increase the flow channels of oil and gas, and improve the productivity index;

[0271] In terms of increasing economic benefits: After optimizing the fracture parameters, the production volume and revenue are relatively increased, and the mining efficiency is improved; moreover, reasonable parameter selection can maximize the output and reduce the production cost, thereby improving the economic benefits;

[0272] In terms of improving the success rate of fracturing: After optimizing the fracture parameters, the propagation path and size of the fracture in the target rock can be more precisely controlled; it helps to ensure that the fracture propagates along the designed direction, avoid unexpected leakage or fracture failure, and improve the success rate of fracturing;

[0273] In terms of reducing environmental risks: By optimizing the fracture parameters, the amount of unnecessary fracturing fluid used can be reduced, the consumption of underground water resources and the environmental impact on the formation can be reduced; at the same time, through more precise fracture control, the interference between the fracture and adjacent oil and gas wells can be reduced, and the connection risk between the formation and the wellbore can be lowered.

[0274] Other advantages, objectives, and features of the present invention will be described to some extent subsequently, and to some extent, will be obvious to those skilled in the art based on an examination of the following text, or can be learned from the practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the following content.

[0275] The above description and the accompanying drawings fully illustrate the embodiments of the present disclosure, enabling those skilled in the art to practice them. Other embodiments may include structural and other changes. The embodiments only represent possible variations. Unless explicitly required, the individual components and functions are optional, and the order of operations can vary. Some parts and features of some embodiments can be included in or replaced by those of other embodiments. The embodiments of the present disclosure are not limited to the structures already described and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the present disclosure is only limited by the appended claims.

Claims

1. An evaluation method for optimizing artificial fracture parameters in a targeted fracturing and acidizing well, characterized in that, Including: Obtaining simulation values, where the simulation values include simulating and calculating the magnitude and distribution of the pressure on the fractures in a fracturing and acidizing well; Predicting the deflection of the tip of the fracture in a targeted fracturing and acidizing well to obtain a deflection prediction value; Coupling multiple times of the simulation values and the deflection prediction value with the parameters of the optimized fracturing fluid; Evaluating the optimization effect of the coupled parameters through geological simulation and laboratory verification.

2. The evaluation method for optimizing artificial fracture parameters of a targeted fracturing and acidizing well according to claim 1, wherein, The obtaining of the simulation values includes: Geological analysis, analyzing the formation structure, lithology, fracture distribution, and formation properties to obtain the geological conditions; Based on the geological conditions, simulating and calculating the magnitude and distribution of the pressure on the fractures in a fracturing and acidizing well.

3. The evaluation method for optimizing artificial fracture parameters in a targeted fracturing and acidizing well according to claim 2, wherein, The obtaining of the optimized fracturing fluid includes: Based on the calculated magnitude and distribution of the pressure, optimizing the components of the fracturing fluid and the content of each component.

4. The evaluation method for optimizing artificial fracture parameters of a targeted fracturing and acidizing well according to claim 1, characterized in that, The evaluating of the optimization effect of the coupled parameters through geological simulation and laboratory verification includes: Performing numerical simulation on the fracture propagation to verify the effectiveness of the optimized parameters; Laboratory simulation, testing the size and shape of the fractures.

5. The evaluation method for optimizing artificial fracture parameters of a targeted fracturing and acidizing well according to claim 2, wherein The simulating and calculating the magnitude of the pressure on the fractures in a fracturing and acidizing well includes: Performing natural logarithm transformation using the correction formula of the regression fitting model to obtain the friction reduction ratio of the friction along the pipe string, where the correction formula is: In the formula, σ is the friction reduction ratio of the friction along the pipe string, D is the diameter of the pipe string, Q is the displacement, and M is the mass concentration of the thickening agent; Calculating the friction along the pipe string based on the friction reduction ratio method of the friction along the pipe string, where the calculation formula is: Wherein, σ is the friction reduction ratio of the pipe string along the way, Δp0 is the friction of the pipe string along the way of clear water, and Δp G,P is the friction of the pipe string along the way of the fracturing fluid; Substituting the friction along the pipe string into the calculation formula of the sidewall pressure of the fracturing and acidizing well to obtain the bottom hole pressure, where the calculation formula is: p w = p wh + p h - ΔP GP , Wherein, P w is the bottom hole pressure, p wh is the wellhead pressure, p h is the hydrostatic pressure; Substituting the bottom hole pressure into the vertical fracture unstable seepage pressure calculation model, and after multiple processes, calculating and analyzing the pressure in the fracture through Laplace transform.

6. The evaluation method for optimizing artificial fracture parameters in a targeted fracturing and acidizing well according to claim 2, characterized in that The simulating and calculating the pressure distribution on the fractures in a fracturing and acidizing well includes: Obtaining the dimensionless bottom hole pressure based on relevant parameters and variables, where the calculation formula is: where p wD is the dimensionless bottom-hole pressure, K is the permeability, h is the reservoir thickness, Δp is the pressure difference, q is the flow rate, μ is the viscosity, and B is the volume coefficient; Solving to obtain the dimensionless formation pressure based on Laplace transform, where the calculation formula is: x D 2 +y D 2 =r D 2 ; where u is the Laplace variable, p D is the dimensionless formation pressure, r D is the dimensionless fracture radial length, K0 is the Bessel function, x D is the dimensionless fracture length in the x direction, y D is the dimensionless fracture length in the y direction; After superimposing the dimensionless bottom hole pressure and the dimensionless formation pressure, obtaining the pressure distribution of an infinitely conductive vertical fracture in the Laplace space, where the pressure distribution is: In the formula, a is the x - coordinate value of any point.

7. The evaluation method for optimizing artificial fracture parameters in a targeted fracturing and acidizing well according to claim 1, characterized in that, The predicting of the deflection of the tip of the fracture in a targeted fracturing and acidizing well to obtain a deflection prediction value includes: Based on the discontinuous displacement on the crack surface, obtaining the stress intensity factor model of a multi - crack body, where the stress intensity factor model is: U x = [2(1 - ν)F3 - yF5]D s + [-(1 - 2ν)F2 - yF4]D n ; U y = [2(1 - ν)F2 - yF4]D s + [2(1 - 2ν)F3 - yF5]D n ; σ x = 2G(2F4 + yF3 - yF6)D s + 2G(-F5 + yF7)D n ; σ y = 2G(-yF6)D s + 2G(-F5 + yF7)D n ; τ xy = 2G(-F5 + yF7)D s + 2G(-yF6)D n ; Wherein, U x is the plane strain in the x direction, and U y is the plane strain in the y direction. F2, F3, F4, F5, F6, and F7 are the first-order partial derivative with respect to x, the first-order partial derivative with respect to y, the second-order mixed partial derivative with respect to x and y, the second-order mixed partial derivative with respect to y and x, the third-order mixed partial derivative with respect to x, y, and y, and the third-order partial derivative with respect to y. σ x , σ y and τ xy are the available stresses, ν is the Poisson's ratio, G is the shear modulus, D s is the tangential discontinuous displacement, and D n is the normal discontinuous displacement; Based on the stress intensity factor model of the uniformly distributed force acting on the crack, obtaining the crack tip intensity factor, where the calculation formula is: Where: K Ι is the modified mode I crack tip strength factor, K ΙΙ is the modified mode II crack tip strength factor, f is the correction factor, K Ι ' is the initial mode I crack tip strength factor, K' ΙΙ is the initial mode II crack tip strength factor, G is the shear modulus, ν is the Poisson's ratio, D s is the tangential discontinuity displacement, D n is the normal discontinuity displacement, and a is the crack half-length.

8. An evaluation method for optimizing artificial fracture parameters in a targeted fracturing and acidizing well according to claim 1, characterized in that The coupling of multiple times of the simulation values and the deflection prediction value with the parameters of the optimized fracturing fluid includes: According to the magnitude and distribution of the pressure on the fractures in a fracturing and acidizing well, non - dimensionalizing and substituting into the Laplace space, calculating the functional relationship between the pressure in the fracture and the fracture length, and obtaining the crack tip stress at each fracture propagation; Based on the crack tip stress, converting it into tangential discontinuous displacement and normal discontinuous displacement; Based on the tangential discontinuous displacement and the normal discontinuous displacement, obtaining the fracture intensity factor; Judge whether the crack starts to crack or / and deflects based on the crack strength factor.

9. An evaluation device for optimizing artificial fracture parameters in a targeted fracturing and acidizing well, characterized in that, An evaluation method for optimizing artificial fracture parameters in a targeted fracturing and acidizing well according to any one of claims 1-8.

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