Method and device for determining long-term flow conductivity of acid etching crack

Abstract

The invention provides a method and a device for determining the long-term flow conductivity of a carbonate rock acid-etched fracture. The method comprises the following steps: acquiring mineral composition, porosity, permeability, formation Young modulus, formation closing stress, formation Poisson's ratio, acid liquor concentration and temperature of rock in a work area; determining a damage factor of the acid etching crack based on rock mineral composition, porosity, permeability, Young modulus, acid liquor concentration and temperature; based on the formation Young modulus, the closing stress, the Poisson's ratio and the acid rock reaction rate, the fracture width change of the acid-etched fracture surface after acid etching is determined; based on the initial fracture width, the Young modulus, the Poisson's ratio and the damage factor, the creep quantity of the acid etching fracture conductivity is determined; and finally, the long-term flow conductivity is determined through the crack width and the formation creep after acid etching. According to the method, lithology, stratum physical properties, rock mechanics parameters, acid etching damage and creep effect are comprehensively considered, and the flow conductivity of the acid etching crack can be rapidly and accurately determined.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum extraction, and in particular relates to a method and a device for determining the long-term conductivity of an acid-etched fracture. Background Art

[0002] Carbonate reservoirs have large oil and gas reserves, accounting for about 48% of the world's crude oil reserves and 28% of natural gas reserves. They have high single-well production and are receiving increasing attention in the world's oil and gas industry. Acid fracturing is one of the key technologies for reservoir reconstruction. The fracture morphology, rock mineral content, porosity and permeability conditions, and rock mechanical parameters after acid erosion will affect the conductivity of acid erosion fractures, and the conductivity of acid erosion fractures has become one of the important indicators for evaluating acid fracturing technology.

[0003] At present, there are defects in the characterization methods of acid-etched fracture space. Most of them take the contour features of a single fracture surface or a single fracture surface as the characteristics of the fracture space, such as roughness, fractal dimension, peak value, tortuosity, etc. Although the degree of fit can characterize the closure characteristics of both sides of the fracture, it cannot reflect the morphology of the fracture space. At present, the conductivity models of acid-etched fractures used to determine the conductivity of acid-etched fractures are mostly empirical models or their improved models, and there is a common problem of inaccurate results in determining the conductivity of acid-etched fractures. The spatial morphology of acid-etched fractures, rock mechanical parameters, closure stress, and fracture contact state can all affect the conductivity of acid-etched fractures. At present, it is still necessary to study technical solutions that can accurately determine the conductivity of acid-etched fractures.

[0004] The acid-etched cracks generated during the acid fracturing process are affected by multiple factors such as closure stress, rock creep and acid damage. The fracture conductivity is difficult to maintain for a long time, which seriously restricts the development effect. The existing prediction methods fail to fully consider the acid damage and creep effects, resulting in a large deviation in the assessment of long-term conductivity. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems existing in the prior art and propose an innovative long-term conductivity prediction model, which comprehensively considers the acid corrosion damage and creep effect of carbonate rocks and quantifies the dynamic change law of fracture width over time. The model can accurately predict the long-term conductivity of fractures under different acid fracturing processes, providing a scientific basis for optimizing the development and design of carbonate reservoirs, and has important theoretical value and engineering significance.

[0006] In order to achieve the above objectives, the present invention provides the following five technical solutions.

[0007] In a first aspect, the present invention provides a method for determining the long-term conductivity of an acid-etched fracture, the method comprising:

[0008] Obtain the rock mineral composition, porosity, permeability, formation Young's modulus, formation closure stress, formation Poisson's ratio, acid concentration and temperature used for transformation in the work area;

[0009] Determine the acid-etched fracture damage factor in the work area based on rock mineral composition, porosity, permeability, formation Young's modulus, acid concentration, and temperature;

[0010] Based on the formation Young's modulus, formation closure stress, formation Poisson's ratio, and formation acid-rock reaction rate, the change in the width of the acid-etched fracture surface in the work area after acid etching is determined;

[0011] Based on the width of the acid-etched cracks in the work area after acid etching, Young's modulus of the formation, Poisson's ratio, and damage factor of the acid-etched cracks, the creep amount of the width of the acid-etched cracks in the work area is determined;

[0012] Based on the crack width after acid etching and crack width after creep in the work area, determine the conductivity of the acid etching cracks in the work area;

[0013] In a second aspect, the present invention provides a device for determining the conductivity of a long-term acid-etched fracture, the device comprising:

[0014] Data acquisition module: used to obtain the rock mineral composition, porosity, permeability, formation Young's modulus, formation closure stress, formation Poisson's ratio, acid concentration and temperature of the work area;

[0015] Acid corrosion damage determination module: used to determine the acid corrosion crack damage factor of the work area based on the rock mineral composition, porosity, permeability, mechanical properties, acid concentration and temperature used for transformation;

[0016] Acid-etched fracture width determination module: used to determine the fracture width of the work area after acid etching based on the Young's modulus, formation closure stress, formation Poisson's ratio, and formation acid-rock reaction rate of the work area;

[0017] Post-creep crack width determination module: used to determine the post-creep crack width of the acid-etched cracks in the work area based on the acid-etched crack damage factor and the post-creep crack width.

[0018] Conductivity determination module: used to determine the long-term conductivity of acid-etched cracks in the work area based on the crack width after acid etching and the crack width after creep.

[0019] In a third aspect, the present invention provides a computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method for determining the long-term conductivity of acid-etched fractures provided in the first aspect is implemented.

[0020] In a fourth aspect, the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the method for determining the long-term conductivity of acid-etched fractures provided in the first aspect.

[0021] In a fifth aspect, the present invention provides a computer program product, which includes a computer program. When the computer program is executed by a processor, it implements the method for determining the long-term conductivity of acid-etched fractures provided in the first aspect.

[0022] Advantages and beneficial effects of the present invention:

[0023] This paper proposes an innovative long-term conductivity prediction model, which comprehensively considers carbonate acid corrosion damage and creep effects, and quantifies the dynamic change of fracture width over time. This model can accurately predict the long-term conductivity of fractures under different acid fracturing processes, providing a scientific basis for optimizing carbonate reservoir development design, and has important theoretical value and engineering significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is the relationship diagram between the seam width deformation and closing stress;

[0025] Figure 2 It is the relationship diagram between the seam width deformation and the reaction time;

[0026] Figure 3 It is the relationship diagram between the seam width deformation and time;

[0027] Figure 4 is the flow conductivity-time relationship diagram;

[0028] Figure 5 The structure diagram of the device for determining the long-term conductivity of acid-etched fractures;

[0029] Figure 6 Determine the module structure diagram for acid erosion damage;

[0030] Figure 7 Module structure diagram for determining the seam width after acid etching. DETAILED DESCRIPTION

[0031] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0032] In the description of this specification, the terms "include", "including", "have", "contain", etc. are all open terms, which mean including but not limited to. The descriptions with reference to the terms "one embodiment", "a specific embodiment", "some embodiments", "for example", etc. mean that the specific features, structures or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. The order of steps involved in each embodiment is used to schematically illustrate the implementation of the present application, and the order of steps is not limited and can be appropriately adjusted as needed.

[0033] An embodiment of the present invention provides a method for determining the long-term conductivity of an acid-etched fracture, the method comprising the following steps:

[0034] Step 101, obtaining the rock mineral composition, porosity, permeability, formation Young's modulus, formation closure stress, formation Poisson's ratio, acid concentration and temperature used for transformation in the work area;

[0035] Step 102, determining the acid-etched fracture damage factor of the work area based on the rock mineral composition, porosity, permeability, formation Young's modulus, acid concentration, and temperature;

[0036] Step 103, based on the formation Young's modulus, formation closure stress, formation Poisson's ratio, and formation acid-rock reaction rate, determine the change in crack width of the acid-etched crack surface in the work area after acid etching;

[0037] Step 104, determining the creep amount of the acid-etched crack width in the work area based on the crack width of the acid-etched crack in the work area after acid etching, the Young's modulus of the formation, the Poisson's ratio, and the acid-etched crack damage factor;

[0038] Step 105, determining the conductivity of the acid-etched cracks in the work area based on the crack width after acid etching and the crack width after creep of the acid-etched cracks in the work area.

[0039] In one embodiment, in step 102, determining the acid-etched fracture damage factor of the work area based on rock mineral composition, porosity, permeability, formation Young's modulus, acid concentration, and temperature includes:

[0040] Step 1021, based on the acid concentration and temperature used for the transformation of the work area, the acid-rock reaction rate of the work area is determined using a kinetic model of the reaction between the acid and the rock;

[0041] Step 1022, based on the acid-rock reaction rate in the work area, determine the porosity change in the work area using a relationship model between the acid-rock reaction rate and the porosity change;

[0042] Step 1023, based on the acid-rock reaction rate in the work area, the change of Young's modulus in the work area is determined using the relationship model between the acid-rock reaction rate and the change of Young's modulus.

[0043] Step 1024, based on the acid-rock reaction rate, porosity change, and Young's modulus change in the work area, the acid-etched crack damage factor of the work area is determined using the relationship between the acid-rock reaction rate, porosity change, and Young's modulus change and the acid-etching damage relationship model.

[0044] In one embodiment, in step 1021, the kinetic model of the reaction between the acid and the rock is:

[0045]

[0046] Where, T 0 is the temperature at room temperature, K; T is the reaction temperature, K; C is the acid concentration, mol / L; A, b, m are constants, dimensionless;

[0047] For example, the relationship model between the acid-rock reaction rate and the acid concentration and temperature used for transformation is:

[0048]

[0049] Where, T 0 is the temperature at room temperature, K; T is the reaction temperature, K; C is the acid concentration, mol / L.

[0050] In one embodiment, in step 1022, the relationship model between the acid-rock reaction rate and the porosity change is:

[0051]

[0052] In the formula, is the porosity change, %; T 0 is the temperature at room temperature, K; T is the reaction temperature, K; C is the acid concentration, mol / L; t is the reaction time, H; S is the reaction area, m 2 ; A, b, m are constants and dimensionless;

[0053] For example, the relationship model between acid rock reaction rate and porosity change is:

[0054]

[0055] In the formula, is the porosity change, %; T 0 is the temperature at room temperature, K; T is the reaction temperature, K; C is the acid concentration, mol / L; t is the reaction time, H; S is the reaction area, m 2 ;

[0056] In one embodiment, in step 1023, the relationship model between the acid-rock reaction rate and the change of Young's modulus is:

[0057]

[0058] In the formula, E c is Young's modulus after acid etching, GPa; E 0 is the initial Young's modulus, GPa; T 0 is the temperature at room temperature, K; T is the reaction temperature, K; C is the acid concentration, mol / L; t is the reaction time, H; S is the reaction area, m 2 ; A, b, m, n are constants and dimensionless;

[0059] For example, the relationship model between acid-rock reaction rate and Young's modulus change is:

[0060]

[0061] In the formula, E c is Young's modulus after acid etching, GPa; E 0 is the initial Young's modulus, GPa; T 0 is the temperature at room temperature, K; T is the reaction temperature, K; C is the acid concentration, mol / L; t is the reaction time, H; S is the reaction area, m 2 ;

[0062] In one embodiment, in step 1024, the relationship model between the acid-rock reaction rate, porosity change, Young's modulus change, and acid corrosion damage is:

[0063]

[0064] Where, T 0 is the temperature at room temperature, K; T is the reaction temperature, K; C is the acid concentration, mol / L; t is the reaction time, H; S is the reaction area, m 2 ; A, b, m, n are constants and dimensionless;

[0065] For example, the relationship model between acid-rock reaction rate, porosity change, Young's modulus change and acid corrosion damage is:

[0066]

[0067] Where, T 0 is the temperature at room temperature, K; T is the reaction temperature, K; C is the acid concentration, mol / L; t is the reaction time, H; S is the reaction area, m 2 ;

[0068] In one embodiment, in step 103, determining the change in crack width of the acid-etched fracture surface in the work area after acid etching based on the formation Young's modulus, formation closure stress, formation Poisson's ratio, and formation acid-rock reaction rate includes:

[0069] Step 1031, determining the closed stress fracture width of the work area based on the Young's modulus, the closure stress and the Poisson's ratio of the formation in the work area;

[0070] Step 1032, based on the acid-rock reaction rate in the work area, the acid-rock reaction fracture width in the work area is determined by using a relationship model between the acid-rock reaction rate and the fracture width;

[0071] Step 1033, determining the width of the crack after acid etching based on the relationship model between the closed stress crack width, the acid-rock reaction crack width and the crack width after acid etching in the work area.

[0072] In one embodiment, in step 1031, the relationship model between the closed stress fracture width and the formation Young's modulus, the formation closure stress, and the formation Poisson's ratio is:

[0073]

[0074] Where N is the number of asperities per unit area of ​​the acid-etched crack, dimensionless; w is the initial crack width, m; R is the radius of the asperity, m; E is the Young's modulus, GPa; ν is the Poisson's ratio, dimensionless; D is the damage factor of the acid-etched crack, dimensionless; σ 1 is the closing stress, MPa; μ is the average value of the micro-asperity height distribution, m; σ is the standard deviation of the micro-asperity height distribution, m; f is the friction coefficient, dimensionless; is the cumulative distribution value of the asperity distribution function; dimensionless.

[0075] In one embodiment, in step 1032, the relationship model between the acid-rock reaction fracture width and the acid-rock reaction rate is:

[0076]

[0077] Where J is the acid-rock reaction rate, g / (cm 2 ·s); t is the reaction time, h; ρ is the rock density, kg / m 3 ; S is the reaction area; m 2 .

[0078] In one embodiment, in step 1033, the relationship model between the crack width after acid etching and the closed stress crack width and the acid-rock reaction crack width is:

[0079] w=w 0 -w(σ)-w(J)

[0080] Wherein, w is the crack width after acid etching, m; w0 is the initial crack width, m; w(σ) is the closed stress crack width, m; w(J) is the acid-rock reaction crack width, m.

[0081] In one embodiment, in step 104, the post-creep seam width determination module determines the post-creep seam width of the working area by the following formula:

[0082]

[0083] In the formula, w 0 is the initial slit width, m; σ 1 is the closing stress, MPa; σ 3 is the confining pressure, MPa; K is the bulk modulus, GPa; G is the shear modulus, GPa; B is the volume parameter, dimensionless; β is the material uniformity parameter, dimensionless; η is the viscosity parameter, dimensionless; α is the load level strength parameter, dimensionless; t σ is the loading time, H; D is the acid corrosion crack damage factor, dimensionless; t B is the accelerated creep time, H; t f For the collapse time, H.

[0084] In one embodiment, in step 105, the fracture conductivity determination module determines the conductivity of the acid-etched fractures in the work area by using the following formula:

[0085]

[0086] Where α is the roughness correction coefficient of the acid-etched crack, dimensionless; w is the crack width after acid etching, m; W kf is the conductivity of acid-etched cracks, μm 2 ·cm.

[0087] In one embodiment, X-ray diffraction experiments are used to determine the rock mineral composition of the work area.

[0088] In one embodiment, porosimetry experiments are used to determine the porosity and permeability of the work area.

[0089] In one embodiment, the formation Young's modulus, formation closure stress, and formation Poisson's ratio may be measured using conventional Young's modulus, closure stress, and Poisson's ratio testing methods, which are not limited herein.

[0090] The present invention also provides a device for determining the long-term conductivity of acid-etched cracks, as described in the following embodiments. Since the principle of the device to solve the problem is similar to the method for determining the long-term conductivity of acid-etched cracks, the implementation of the device can refer to the implementation of the method for determining the conductivity of acid-etched cracks, and the repeated parts will not be repeated.

[0091] An embodiment of the present invention provides a device for determining the long-term conductivity of an acid-etched fracture. The device may specifically include: Figure 5 As shown:

[0092] Data acquisition module 201: used to acquire the rock mineral composition, porosity, permeability, formation Young's modulus, formation closure stress, formation Poisson's ratio, acid concentration and temperature of the work area;

[0093] Acid corrosion damage determination module 202: used to determine the acid corrosion crack damage factor of the work area based on the rock mineral composition, porosity, permeability, mechanical properties, acid concentration and temperature used for transformation in the work area;

[0094] A post-acid-etching fracture width determination module 203: used to determine the post-acid-etching fracture width of the work area based on the Young's modulus of the formation, the formation closure stress, the formation Poisson's ratio, and the formation acid-rock reaction rate;

[0095] The post-creep crack width determination module 204 is used to determine the post-creep crack width of the acid-etched cracks in the work area based on the acid-etched crack damage factor and the post-creep crack width.

[0096] The flow conductivity determination module 205 is used to determine the long-term flow conductivity of the acid-etched cracks in the work area based on the crack width after acid etching and the crack width after creep.

[0097] In one embodiment, the acid erosion damage determination module 202 includes: Figure 6 As shown:

[0098] Acid-rock reaction rate determination submodule 2021: Based on the acid concentration and temperature used for the transformation of the work area, the acid-rock reaction rate of the work area is determined using the acid-rock reaction kinetic model;

[0099] Porosity change determination submodule 2022: used to determine the porosity change of the work area based on the acid-rock reaction rate of the work area and using the relationship model between the acid-rock reaction rate and the porosity change;

[0100] The Young's modulus change determination submodule 2023 is used to determine the Young's modulus change in the work area based on the acid-rock reaction rate in the work area and using the acid-rock reaction rate and Young's modulus change relationship model.

[0101] Acid corrosion damage determination submodule 2024: used to determine the acid corrosion crack damage factor of the work area based on the acid-rock reaction rate, porosity change, and Young's modulus change in the work area, using the relationship between the acid-rock reaction rate, porosity change, and Young's modulus change and the acid corrosion damage relationship model.

[0102] In one embodiment, the post-etching seam width determination module 203 includes: Figure 7 Shown:

[0103] The closed stress fracture width determination submodule 2031 determines the closed stress fracture width of the work area based on the Young's modulus, the formation closure stress, and the formation Poisson's ratio of the work area;

[0104] Acid rock reaction fracture width determination submodule 2032: used to determine the acid rock reaction fracture width of the work area based on the acid rock reaction rate of the work area and using the acid rock reaction rate and fracture width relationship model;

[0105] The post-acid-etching seam width determination submodule 2033 is used to determine the post-acid-etching seam width based on the relationship model between the closed stress seam width in the work area, the acid-rock reaction seam width and the post-acid-etching seam width.

[0106] An embodiment of the present invention further provides a computer device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the above-mentioned method for determining the conductivity of acid-etched fractures is implemented.

[0107] An embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the above-mentioned method for determining the conductivity of acid-etched fractures is implemented.

[0108] An embodiment of the present invention further provides a computer program product, which includes a computer program. When the computer program is executed by a processor, the above-mentioned method for determining the conductivity of acid-etched fractures is implemented.

[0109] Embodiment 1:

[0110] This embodiment provides a method for determining the long-term conductivity of an acid-etched fracture, the method comprising:

[0111] 1. Obtain the rock mineral composition, porosity, permeability, Young's modulus, formation closure stress, formation Poisson's ratio, acid concentration and temperature used for transformation in the work area.

[0112] Among them, X-ray diffraction experiments are used to determine the mineral composition of rocks; porosity and permeability are determined by pore permeability measurement experiments;

[0113] The results are shown in Table 1.

[0114] Table 1

[0115] Physical parameters Unit symbol Numeric Formation closure stress (MPa) P 5-50 <![CDATA[Permeability (um 3 )]]> K 1 Porosity(%) Φ 0.7 Young's modulus of formation (GPa) E 50 Formation Poisson's ratio ν 0.25 Acid concentration C 1.5-6 Acid temperature T 25-100 Dolomite content ％ 90-100

[0116] 2. Fit and determine the kinetic model of the reaction between acid and rock, fit and determine the relationship model between the acid-rock reaction rate and porosity change, fit and determine the relationship model between the acid-rock reaction rate and Young's modulus change, fit and determine the relationship model between the acid-rock reaction rate, porosity change, Young's modulus change and acid corrosion damage; specifically including:

[0117] Twelve cores were obtained from the work area and numbered 1-12. The porosity difference, permeability, Young's modulus ratio, Poisson's ratio, and acid-rock reaction rate of the 12 cores before and after acid etching were determined through indoor experiments. The results are shown in Table 2.

[0118] Table 2

[0119]

[0120]

[0121] 3. Based on the acid concentration and temperature used in the reconstruction of the work area, the acid-rock reaction rate and acid-etched crack damage factor of the work area were determined using the acid-rock reaction kinetic model, as shown in Table 3.

[0122] Table 3

[0123]

[0124]

[0125] 4. Through indoor experiments, the number of micro-asperities per unit area of ​​acid-etched cracks, initial crack width, micro-asperity radius, acid-etched crack damage factor, closure stress, average micro-asperity height distribution, standard deviation of micro-asperity height distribution, and friction coefficient were determined. The results are shown in Table 4.

[0126] Table 4

[0127] Physical parameters Unit symbol Numeric Number of micro-convex bodies per unit area of ​​acid-etched cracks N 1000000 Initial seam width (m) w 0.1 Radius of microconvex body (m) R 0.000001 Acid etch crack damage factor D 0.3 Closing stress (MPa) <![CDATA[σ 1 ]]> 0-100 Average value of asperity height distribution μ 0.3 Standard deviation of asperity height distribution σ 0.3 Friction coefficient f 0.6

[0128] 5. Based on the Young's modulus, closure stress and Poisson's ratio of the formation, the fracture width after closure of the work area is determined by the formula. The results are shown in Table 5 and Figure 1 shown.

[0129] Table 5

[0130]

[0131] 5. Based on the Young's modulus, closure stress and Poisson's ratio of the formation, the width of the seam after acid etching in the work area is determined by the formula, as shown in Table 6 and Figure 2 As shown:

[0132] Table 6

[0133] t / s 10 50 100 150 200 250 300 W / mm 0.04 0.21 0.42 0.62 0.83 1.04 1.25

[0134] 6. Based on the Young's modulus, closure stress, Poisson's ratio and acid-etched fracture damage factor, the width of the acid-etched fractures in the work area after creep is determined by the formula, as shown in Table 7 and Figure 3 shown.

[0135] Table 7

[0136] t / s 10 1000 2000 3000 4000 5000 10000 75000 W / mm 1.54 3.05 2.70 2.44 2.44 2.44 2.44 5.28

[0137] 7. Based on the crack width after acid etching and the crack width after creep, the long-term conductivity of the acid-etched cracks in the work area is determined by the formula, as shown in Table 8 and Figure 4 shown.

[0138] Table 8

[0139]

[0140] The above description is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several modifications and improvements without departing from the inventive concept, which all belong to the protection scope of the present invention.

Claims

1. A method for determining the long-term conductivity of an acid-etched fracture, the method comprising: Step 101, obtaining the rock mineral composition, porosity, permeability, formation Young's modulus, formation closure stress, formation Poisson's ratio, acid concentration and temperature used for transformation in the work area; Step 102, determining the acid-etched fracture damage factor of the work area based on the rock mineral composition, porosity, permeability, formation Young's modulus, acid concentration, and temperature; Step 103, based on the formation Young's modulus, formation closure stress, formation Poisson's ratio, and acid-rock reaction rate, determine the change in crack width of the acid-etched crack surface in the work area after acid etching; Step 104, determining the creep amount of the acid-etched crack width in the work area based on the crack width of the acid-etched crack in the work area after acid etching, the Young's modulus of the formation, the Poisson's ratio, and the acid-etched crack damage factor; Step 105, determining the conductivity of the acid-etched cracks in the work area based on the crack width after acid etching and the crack width after creep of the acid-etched cracks in the work area.

2. The method according to claim 1, characterized in that The acid-etched crack damage factor of the work area determined in step 102 includes: Step 1021, based on the acid concentration and temperature used for the transformation of the work area, the acid-rock reaction rate of the work area is determined using a kinetic model of the reaction between the acid and the rock; Step 1022, based on the acid-rock reaction rate in the work area, determine the porosity change in the work area using a relationship model between the acid-rock reaction rate and the porosity change; Step 1023, based on the acid-rock reaction rate in the work area, using the acid-rock reaction rate and Young's modulus change relationship model to determine the Young's modulus change in the work area; Step 1024, based on the acid-rock reaction rate, porosity change, and Young's modulus change in the work area, the acid-etched crack damage factor of the work area is determined using the relationship between the acid-rock reaction rate, porosity change, and Young's modulus change and the acid-etched crack damage model.

3. The method according to claim 2, characterized in that The relationship model between the acid-rock reaction rate and the porosity change in step 1022 is as follows: In the formula, is the porosity change, %; T0 is the temperature at room temperature, K; T is the reaction temperature, K; C is the acid concentration, mol / L; t is the reaction time, H; S is the reaction area, m 2 ; A, b, m are constants and dimensionless; The relationship model between the acid-rock reaction rate and the Young's modulus change in step 1023 is as follows: In the formula, E c is the Young's modulus after acid etching, GPa; E0 is the initial Young's modulus, GPa; n is a constant, dimensionless; The acid-etched crack damage model in step 1024 is as follows: Where Dc is the acid corrosion crack damage factor.

4. The method according to claim 3, characterized in that Determining the change in crack width of the acid-etched fracture surface in the work area after acid etching based on the formation Young's modulus, formation closure stress, formation Poisson's ratio, and acid-rock reaction rate in step 103 includes: Step 1031, determining the closed stress fracture width of the work area based on the Young's modulus, the closure stress and the Poisson's ratio of the formation in the work area; Step 1032, based on the acid-rock reaction rate in the work area, the acid-rock reaction fracture width in the work area is determined by using a relationship model between the acid-rock reaction rate and the fracture width; Step 1033, determining the width of the crack after acid etching based on the relationship model between the closed stress crack width, the acid-rock reaction crack width and the crack width after acid etching in the work area.

5. The method according to claim 4, characterized in that In step 1031, the relationship model between the closed stress fracture width and the formation Young's modulus, formation closure stress, and formation Poisson's ratio is: Wherein, N is the number of micro-asperities per unit area of ​​the acid-etched crack, dimensionless; w is the initial crack width, m; R is the radius of the micro-asperity, m; E is the Young's modulus, GPa; ν is the Poisson's ratio, dimensionless; D is the damage factor of the acid-etched crack, dimensionless; σ1 is the closure stress, MPa; μ is the average value of the micro-asperity height distribution, m; σ is the standard deviation of the micro-asperity height distribution, m; f is the friction coefficient, dimensionless; is the cumulative distribution value of the asperity distribution function; dimensionless; In step 1032, the relationship model between the acid-rock reaction crack width and the acid-rock reaction rate is: Where J is the acid-rock reaction rate, g / (cm 2 ·s); t is the reaction time, h; ρ is the rock density, kg / m 3 ; S is the reaction area; m 2 ; In step 1033, the relationship model between the crack width after acid etching and the closed stress crack width and the acid-rock reaction crack width is: w=w0-w(σ)-w(J) Where, w is the crack width after acid etching, m; w0 is the initial crack width, m; w(σ) is the closed stress crack width, m; w(J) is the width of acid-rock reaction fracture, m.

6. The method according to claim 5, characterized in that Based on the damage factor of the acid-etched cracks in the work area and the crack width after acid-etching, the crack width of the acid-etched cracks after creep in the work area is determined by using the relationship model between the formation creep and the crack width of the acid-etched cracks. The relationship model between the formation creep and the acid-etched fracture width is: Wherein, w0 is the initial crack width, m; σ1 is the closing stress, MPa; σ3 is the confining pressure, MPa; K is the bulk modulus, GPa; G is the shear modulus, GPa; B is the volume parameter, dimensionless; β is the material uniformity parameter, dimensionless; η is the viscosity parameter, dimensionless; α is the load level strength parameter, dimensionless; t σ is the loading time, H; D is the acid corrosion crack damage factor, dimensionless; t B is the accelerated creep time, H; t f For the collapse time, H.

7. The method according to claim 6, characterized in that In step 105, the relationship model between the seam width after acid etching and the flow conductivity is determined by the following formula:

8. A device for determining conductivity of an acid-etched fracture, the device comprising: Data acquisition module: used to obtain the rock mineral composition, porosity, permeability, formation Young's modulus, formation closure stress, formation Poisson's ratio, acid concentration and temperature of the work area; Acid corrosion damage determination module: used to determine the acid corrosion crack damage factor of the work area based on the rock mineral composition, porosity, permeability, mechanical properties, acid concentration and temperature used for transformation; Acid-etched fracture width determination module: used to determine the fracture width of the work area after acid etching based on the Young's modulus, formation closure stress, formation Poisson's ratio, and formation acid-rock reaction rate of the work area; Post-creep crack width determination module: used to determine the post-creep crack width of the acid-etched cracks in the work area based on the acid-etched crack damage factor and the post-creep crack width; Conductivity determination module: used to determine the long-term conductivity of acid-etched cracks in the work area based on the crack width after acid etching and the crack width after creep.

9. The device according to claim 8, characterized in that The acid corrosion damage determination module comprises: Acid-rock reaction rate determination submodule: Based on the acid concentration and temperature used in the transformation of the work area, the acid-rock reaction rate of the work area is determined using the acid-rock reaction kinetic model; Porosity change determination submodule: used to determine the porosity change in the work area based on the acid-rock reaction rate in the work area and using the relationship model between the acid-rock reaction rate and the porosity change; Young's modulus change determination submodule: used to determine the Young's modulus change in the work area based on the acid-rock reaction rate in the work area and using the acid-rock reaction rate and Young's modulus change relationship model; Acid corrosion damage determination submodule: It is used to determine the acid corrosion crack damage factor of the work area based on the acid-rock reaction rate, porosity change, and Young's modulus change of the work area, using the relationship between the acid-rock reaction rate, porosity change, and Young's modulus change and the acid corrosion damage relationship model; The post-acid-etching seam width determination module comprises: Submodule for determining the width of closed stress fractures: Based on the Young's modulus, closure stress and Poisson's ratio of the formation in the work area, the width of closed stress fractures in the work area is determined; Acid rock reaction fracture width determination submodule: used to determine the acid rock reaction fracture width in the work area based on the acid rock reaction rate in the work area and using the acid rock reaction rate and fracture width relationship model; Submodule for determining the width of cracks after acid etching: used to determine the width of cracks after acid etching based on the relationship model between the closed stress crack width in the work area, the acid-rock reaction crack width and the width of cracks after acid etching.

10. A computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the method for determining conductivity of acid-etched fractures according to any one of claims 1 to 5.

Images