A method and device for evaluating the complexity of shale gas reservoir fractures

Abstract

The present application discloses a method and device for evaluating the complexity of shale gas reservoir fractures, and relates to the field of petroleum and natural gas engineering technology. The method comprises: obtaining the Young's modulus and Poisson's ratio of each layer in the standard core; determining the layer mechanical index based on the Young's modulus and Poisson's ratio, dividing the layers, and updating the assignment of each layer; determining the total mechanical parameter layer assignment according to the assignment of each layer, and dividing the Z layer; determining the layer weight coefficient according to the total mechanical parameter layer assignment and the layer mechanical index of the Z layer; determining the communication coefficient based on the layer weight coefficient, the layer mechanical index and the total mechanical parameter layer assignment; and classifying the standard core according to the communication coefficient to determine the complexity of the fractures in the corresponding reservoir section. The present application solves the problem that the existing fracture complexity evaluation methods are all based on the perspective of natural fractures, ignoring the bedding development characteristics of rocks. The present application can quickly evaluate the complexity of fractures, and greatly reduces the cost.

Description

Technical Field

[0001] The present application relates to the field of petroleum and natural gas engineering technology, and in particular to a method and device for evaluating the complexity of shale gas reservoir fractures. Background Art

[0002] At present, a lot of research has been carried out on the complexity of fractures in unconventional tight oil and gas reservoirs. Through investigation, it can be found that there are mainly three typical methods. (1) Chinese patent with publication number CN107064454A discloses a core determination method for the development degree of reservoir fractures, which is divided into the following steps: core splicing; summary and identification of natural fracture characteristics; imaging logging calibration; final determination of natural fractures; and judgment of fracture development degree. (2) Chinese patent with publication number CN114325854A discloses a method for judging the development degree of fractures of different levels in cores. The method includes: firstly counting the number of natural fractures in the core of the target layer to obtain the linear density value of natural fractures of level I core and the linear density value of natural fractures of level II; adding the linear density value of natural fractures of level I core and the linear density value of natural fractures of level II core to obtain the total density value, and comprehensively judging the development degree of natural fractures of different levels in the core scale according to the total density value. Thus, the quantitative characterization of the development degree of fractures of different levels in the core is achieved. (3) Chinese patent publication number CN106126936A discloses a comprehensive evaluation method for the effectiveness of cracks in dense low-permeability reservoirs. This method proposes a quantitative evaluation method for the effectiveness of cracks in dense low-permeability reservoirs based on the crack effectiveness index method, according to the main influencing factors of the effectiveness of natural cracks, including crack formation time, crack direction, crack inclination, crack development degree, ground stress direction and ground stress magnitude.

[0003] From the above analysis, it can be seen that most of the current methods evaluate the complexity of fractures from the perspective of natural fractures, but none of them evaluate the complexity of fractures from the perspective of geological and engineering integration, especially the prominent characteristics of shale gas reservoir bedding development, which is also the core factor affecting the complexity of fractures. Summary of the invention

[0004] The embodiments of the present application provide a method and device for evaluating the complexity of shale gas reservoir fractures, thereby solving the problem that the existing methods for evaluating the complexity of fractures are all based on the perspective of natural fractures and ignore the bedding development characteristics of rocks.

[0005] In the first aspect, an embodiment of the present application provides a method for evaluating the complexity of shale gas reservoir fractures, comprising: obtaining a standard core of a reservoir section, and obtaining the Young's modulus and the Poisson's ratio of each layer in the standard core; dividing the layers based on the Young's modulus and the Poisson's ratio of the layers, and updating the assignments of the divided layers; determining the total mechanical parameter layer assignment according to the assignments of each layer; determining the layer mechanical index according to the Young's modulus and the Poisson's ratio of the layers; dividing the Z layers based on the total mechanical parameter layer assignment, and determining the layer weight coefficient according to the total mechanical parameter layer assignment and the layer mechanical index of the divided Z layers; determining the communication coefficient based on the layer weight coefficient, the layer mechanical index and the total mechanical parameter layer assignment; grading the standard core according to the communication coefficient to determine the complexity of the fractures in the corresponding reservoir section.

[0006] In combination with the first aspect, in a possible implementation, the layers are divided based on the Young's modulus of the layer and the Poisson's ratio of the layer, and the assignment of each divided layer is updated, including: based on the bedding structure of the standard core, the bedding other than the top layer and the bottom layer of the standard core is determined as the target bedding; within the target bedding, the communicating layer and the blocking layer are divided based on the Young's modulus of the layer and the Poisson's ratio of the layer; the bedding within the target bedding is assigned values ​​in descending order from the communicating layer to the blocking layer.

[0007] In combination with the first aspect, in a possible implementation, the dividing of the communication layer and the barrier layer based on the Young's modulus of the layer and the Poisson's ratio of the layer respectively includes: dividing the beddings where the maximum value and the minimum value of the Young's modulus of the layer in the target bedding are located into a first Y barrier layer and a first Y communication layer respectively; dividing the beddings where the value of the Young's modulus of the layer in the target bedding is greater than the upper and lower adjacent beddings into a second Y barrier layer; dividing the beddings where the value of the Young's modulus of the layer in the target bedding is less than the upper and lower adjacent beddings into a second Y channel layer; The target bedding is divided into a through layer; the remaining undivided beddings in the target bedding are divided into a third Y layer; the beddings where the minimum and maximum values ​​of the layer Poisson's ratio in the target bedding are located are divided into a first P barrier layer and a first P communication layer respectively; the beddings in the target bedding where the value of the layer Poisson's ratio is smaller than that of the upper and lower adjacent beddings are divided into a second P barrier layer; the beddings in the target bedding where the value of the layer Poisson's ratio is larger than that of the upper and lower adjacent beddings are divided into a second P communication layer; the remaining undivided beddings in the target bedding are divided into a third P layer.

[0008] In combination with the first aspect, in a possible implementation, the layering within the target layer is assigned values ​​in descending order from the communicating layer to the blocking layer, including: assigning the layer Young's modulus of the first Y blocking layer and the layer Poisson's ratio of the first P blocking layer to a first value; assigning the layer Young's modulus of the first Y communicating layer and the layer Poisson's ratio of the first P communicating layer to a fifth value; assigning the layer Young's modulus of the second Y blocking layer and the layer Poisson's ratio of the second P blocking layer to a second value; assigning the layer Young's modulus of the second Y communicating layer and the layer Poisson's ratio of the second P communicating layer to a fourth value; assigning the layer Young's modulus of the third Y layer and the layer Poisson's ratio of the third P layer to a third value; wherein, the first value < the second value < the third value < the fourth value < the fifth value.

[0009] In combination with the first aspect, in a possible implementation manner, determining the total mechanical parameter layer assignment according to the assignments of each level includes:

[0010] ;

[0011] In the formula, Assign the total mechanical parameter layer of layer i, is the value of Young's modulus of layer i, is the value of the Poisson's ratio of the layer i.

[0012] In combination with the first aspect, in a possible implementation manner, determining the layer mechanical index according to the layer Young's modulus and the layer Poisson's ratio includes:

[0013] ;

[0014] In the formula, is the layer mechanical index of layer i, is the Young's modulus of the layer i, is the Poisson's ratio of the layer i.

[0015] In combination with the first aspect, in a possible implementation, the Z-level division based on the total mechanical parameter layer assignment includes: dividing the stratum where the minimum value of the total mechanical parameter layer assignment is located into the first Z blocking layer; dividing the stratum with the smallest value of the layer Young's modulus into the first Z communication layer; dividing the stratum with a value of the layer Young's modulus greater than that of the two upper and lower adjacent strata into the second Z blocking layer; dividing the stratum with a value of the layer Young's modulus less than that of the two upper and lower adjacent strata into the second Z communication layer; and dividing the remaining Z blocking layers and Z communication layers that have not been divided into the third Z layer.

[0016] In combination with the first aspect, in a possible implementation manner, determining a layer weight coefficient according to the total mechanical parameter layer value of the divided Z level and the layer mechanical index includes:

[0017] ;

[0018] ;

[0019] ;

[0020] ;

[0021] In the formula, is the layer mechanical index corresponding to the first Z communication layer, is the layer mechanical index corresponding to the second Z communication layer, is the layer mechanical index corresponding to the first Z barrier layer, is the layer mechanical index corresponding to the second Z barrier layer, is the layer weight coefficient of the first Z communication layer, is the layer weight coefficient of the second Z communication layer, is the layer weight coefficient of the first Z-blocking layer, is the layer weight coefficient of the second Z-blocking layer, is the layer mechanical index of bedding i within the target bedding, and n is the total number of target beddings in the standard core.

[0022] In combination with the first aspect, in a possible implementation manner, determining the communication coefficient based on the layer weight coefficient, the layer mechanical index and the total mechanical parameter layer assignment includes:

[0023] ;

[0024] Where K is the communication coefficient, is the layer weight coefficient of the first Z communication layer, is the layer mechanical index corresponding to the first Z communication layer, Assign the total mechanical parameter layer of the first Z communication layer, The first Z communication layer Layers, is the bedding number of the first Z communication layer, is the layer weight coefficient of the second Z communication layer, is the layer mechanical index corresponding to the second Z communication layer, Assign values ​​to the total mechanical parameter layer of the second Z communication layer, For the second Z communication layer Layers, is the bedding number of the second Z communication layer, is the layer weight coefficient of the first Z-blocking layer, is the layer mechanical index corresponding to the first Z barrier layer, Assign the total mechanical parameter layer of the first Z barrier layer, is the first Z barrier layer Layers, is the bedding number of the first Z barrier layer, is the layer weight coefficient of the second Z-blocking layer, is the layer mechanical index corresponding to the second Z barrier layer, Assign the total mechanical parameter layer of the second Z barrier layer, is the first Z barrier layer Layers, is the bedding number of the second Z barrier layer, is the layer mechanical index of bedding i within the target bedding, is the total mechanical parameter layer assignment for bedding i within the target bedding, and n is the total number of target beddings in the standard core.

[0025] In a second aspect, an embodiment of the present application provides an evaluation device for the complexity of shale gas reservoir fractures, comprising: an acquisition module for acquiring a standard core of a reservoir section, and acquiring the Young's modulus and the Poisson's ratio of each layer in the standard core; a layer assignment module for dividing the layers based on the Young's modulus and the Poisson's ratio of the layers, and updating the assignments of the divided layers; a total mechanical parameter layer assignment module for determining the total mechanical parameter layer assignment according to the assignments of each layer; a layer mechanical index module for determining the layer mechanical index according to the Young's modulus and the Poisson's ratio of the layers; a layer weight coefficient module for dividing the Z layers based on the total mechanical parameter layer assignment, and determining the layer weight coefficient according to the total mechanical parameter layer assignment and the layer mechanical index of the divided Z layers; a communication coefficient module for determining the communication coefficient based on the layer weight coefficient, the layer mechanical index and the total mechanical parameter layer assignment; a complexity rating module for grading the standard core according to the communication coefficient to determine the complexity of the fractures in the corresponding reservoir section.

[0026] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0027] The embodiment of the present application can simplify the calculation by dividing the layers and assigning values; by determining the layer weight coefficient, the influence of different layers on the complexity of the fracture can be determined; by the communication coefficient, the communication ability between layers can be characterized. It effectively solves the problem that the existing fracture complexity evaluation methods are all based on the perspective of natural fractures, ignoring the bedding development characteristics of rocks, and can quickly evaluate the complexity of fractures, greatly reducing costs, and providing a basis and direct reference for the optimization of shale gas reservoir volume transformation. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 A flow chart of a method for evaluating the complexity of shale gas reservoir fractures provided in an embodiment of the present application;

[0030] Figure 2 A schematic diagram of the structure of a shale gas reservoir fracture complexity evaluation device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The following describes some of the techniques involved in the embodiments of the present application to facilitate understanding, and they should be considered as merely exemplary. Therefore, it should be appreciated by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present application. Similarly, for the sake of clarity and conciseness, some descriptions of well-known functions and structures are omitted in the following description.

[0033] Figure 1 This is a flow chart of a method for evaluating the complexity of shale gas reservoir fractures provided in an embodiment of the present application, including steps 101 to 107. Among them, Figure 1 This is only an execution order shown in the embodiment of the present application, and does not represent the only execution order of a method for evaluating the complexity of shale gas reservoir fractures. In the case that the final result can be achieved, Figure 1 The steps shown may be performed in parallel or reversed.

[0034] Step 101: Obtain a standard core of the reservoir section, and obtain the Young's modulus and Poisson's ratio of each layer in the standard core. In the embodiment of the present application, a shale rock sample corresponding to the reservoir section to be evaluated is obtained, processed into a standard core, and the Young's modulus and Poisson's ratio of the standard core and the Young's modulus and Poisson's ratio of each layer in the standard core are obtained. Exemplarily, the standard core is a cylinder with a diameter of 2.5 cm and a height of 5 cm.

[0035] In the embodiments of the present application, the layer Young's modulus and layer Poisson's ratio of the standard core can be measured and calculated by mechanical tensile testing, ultrasonic method and the like.

[0036] Step 102: divide the layers based on the layer Young's modulus and the layer Poisson's ratio, and update the assignment of each divided layer. In the embodiment of the present application, based on the bedding structure of the standard core, the bedding other than the top layer and the bottom layer of the standard core is determined as the target bedding. In the target bedding, the communication layer and the barrier layer are divided based on the layer Young's modulus and the layer Poisson's ratio. The bedding in the target bedding is assigned in descending order from the communication layer to the barrier layer.

[0037] Specifically, the total number of beddings (n) of the standard core is determined. In the actual calculation in the subsequent steps, only the beddings (n-2) except the bedding between the top layer and the bottom layer are calculated, and the n-2 layers except the top layer and the bottom layer are taken as the target beddings.

[0038] The communication layer and the barrier layer are divided based on the layer Young's modulus and the layer Poisson's ratio, respectively, as follows: the beddings where the maximum and minimum values ​​of the Young's modulus in the target bedding are located are divided into the first Y barrier layer and the first Y communication layer, respectively. The beddings where the value of the Young's modulus in the target bedding is greater than the upper and lower adjacent beddings are divided into the second Y barrier layer. The beddings where the value of the Young's modulus in the target bedding is less than the upper and lower adjacent beddings are divided into the second Y communication layer. The remaining undivided beddings in the target bedding are divided into the third Y layer. The beddings where the minimum and maximum values ​​of the Poisson's ratio in the target bedding are located are divided into the first P barrier layer and the first P communication layer, respectively. The beddings where the value of the Poisson's ratio in the target bedding is less than the upper and lower adjacent beddings are divided into the second P barrier layer. The beddings where the value of the Poisson's ratio in the target bedding is greater than the upper and lower adjacent beddings are divided into the second P communication layer. The remaining undivided beddings in the target bedding are divided into the third P layer.

[0039] The layers in the target layer are assigned values ​​in descending order from the communication layer to the barrier layer, as follows: the first value is assigned to the layer Young's modulus of the first Y barrier layer and the layer Poisson's ratio of the first P barrier layer. The fifth value is assigned to the layer Young's modulus of the first Y communication layer and the layer Poisson's ratio of the first P communication layer. The second value is assigned to the layer Young's modulus of the second Y barrier layer and the layer Poisson's ratio of the second P barrier layer. The fourth value is assigned to the layer Young's modulus of the second Y communication layer and the layer Poisson's ratio of the second P communication layer. The third value is assigned to the layer Young's modulus of the third Y layer and the layer Poisson's ratio of the third P layer. Among them, the first value < the second value < the third value < the fourth value < the fifth value.

[0040] The order of the layers in the target layer from the communication layer to the barrier layer is: the first Y communication layer, the second Y communication layer, the third Y layer, the second Y barrier layer, the first Y barrier layer, and the first P communication layer, the second P communication layer, the third P layer, the second P barrier layer, and the first P barrier layer. According to this order, the fifth value, the fourth value, the third value, the second value, and the first value are assigned in sequence.

[0041] For example, the fifth value of the present application is set to 5, the fourth value is set to 4, the third value is set to 3, the second value is set to 2, and the first value is set to 1. It should be clear to those skilled in the art that the specific values ​​set here are only one embodiment of the present application, and those skilled in the art can set the specific values ​​according to actual conditions, for example, the fifth value, the fourth value, the third value, the second value, and the first value are set to 10, 9, 8, 7, and 6 respectively.

[0042] Step 103: Determine the total mechanical parameter layer assignment according to the assignment of each level. In the embodiment of the present application, determine the total mechanical parameter layer assignment according to the assignment of each level, including:

[0043] .

[0044] In the formula, is the total mechanical parameter layer assignment for layer i, dimensionless, is the value of the Young's modulus of the layer i, dimensionless, is the assignment of the Poisson's ratio of bedding i, which is dimensionless. The value of i is an integer between (1, n-2). The bedding of the standard core starts from 0 and is as follows: bedding 0, bedding 2, ..., bedding n-1. The target bedding of the standard core is bedding 1, bedding 2, ..., bedding n-2 excluding the top and bottom beddings.

[0045] Step 104: Determine the layer mechanical index according to the layer Young's modulus and the layer Poisson's ratio. In the embodiment of the present application, the layer mechanical index is determined according to the layer Young's modulus and the layer Poisson's ratio, including:

[0046] .

[0047] In the formula, is the layer mechanical index of bedding i, MPa (megapascals), is the Young's modulus of the layer i, MPa (megapascals), is the Poisson's ratio of the layer of bedding i, dimensionless.

[0048] Step 105: Divide the Z levels based on the total mechanical parameter layer assignment, and determine the layer weight coefficient according to the total mechanical parameter layer assignment and the layer mechanical index of the divided Z levels. In the embodiment of the present application, the bedding where the minimum value of the total mechanical parameter layer assignment is located is divided into the first Z barrier layer. The bedding with the smallest layer Young's modulus value is divided into the first Z communication layer. The bedding with a layer Young's modulus value greater than the upper and lower adjacent beddings is divided into the second Z barrier layer. The bedding with a layer Young's modulus value less than the upper and lower adjacent beddings is divided into the second Z communication layer. The remaining undivided Z barrier layers and Z communication layers are divided into the third Z layer.

[0049] In the embodiment of the present application, the layer weight coefficient of each total mechanical parameter layer assignment is determined based on the total mechanical parameter layer assignment and the layer mechanical index of the Z level, as follows:

[0050] ; ; ; .

[0051] In the formula, is the layer mechanical index corresponding to the first Z communication layer, MPa (megapascals), is the layer mechanical index corresponding to the second Z communication layer, MPa (megapascals), is the layer mechanical index corresponding to the first Z barrier layer, MPa (megapascals), is the layer mechanical index corresponding to the second Z barrier layer, MPa (megapascals), is the layer weight coefficient of the first Z communication layer, dimensionless, is the layer weight coefficient of the second Z communication layer, dimensionless, is the layer weight coefficient of the first Z barrier layer, dimensionless, is the layer weight coefficient of the second Z barrier layer, dimensionless, is the layer mechanical index of bedding i within the target bedding, MPa (megapascals), and n is the total number of target beddings in the standard core.

[0052] Step 106: Determine the communication coefficient based on the layer weight coefficient, the layer mechanical index and the total mechanical parameter layer assignment. In the embodiment of the present application, the communication coefficient is determined based on the layer weight coefficient, the layer mechanical index and the updated total mechanical parameter layer assignment as follows:

[0053] .

[0054] Where K is the communication coefficient, dimensionless, is the layer weight coefficient of the first Z communication layer, dimensionless, is the layer mechanical index corresponding to the first Z communication layer, MPa (megapascals), Assign the total mechanical parameter layer of the first Z communication layer, dimensionless, The first Z communication layer Layers, is the bedding number of the first Z communication layer, is the layer weight coefficient of the second Z communication layer, dimensionless, is the layer mechanical index corresponding to the second Z communication layer, MPa (megapascals), Assign the total mechanical parameter layer of the second Z communication layer, dimensionless, For the second Z communication layer Layers, is the bedding number of the second Z communication layer, is the layer weight coefficient of the first Z barrier layer, dimensionless, is the layer mechanical index corresponding to the first Z barrier layer, MPa (megapascals), Assign the total mechanical parameter layer of the first Z barrier layer, dimensionless, is the first Z barrier layer Layers, is the bedding number of the first Z barrier layer, is the layer weight coefficient of the second Z barrier layer, dimensionless, is the layer mechanical index corresponding to the second Z barrier layer, MPa (megapascals), Assign the total mechanical parameter layer of the second Z barrier layer, dimensionless, is the first Z barrier layer Layers, is the bedding number of the second Z barrier layer, is the layer mechanical index of bedding i within the target bedding, MPa (megapascals), It is the total mechanical parameter layer assignment of bedding i within the target bedding, dimensionless, and n is the total number of target beddings in the standard core.

[0055] Among them, the communication coefficient represents the ability of the layers to communicate with each other. The larger the value of the communication coefficient, the greater the potential for volume fracturing to form a complex fracture network, and the higher the complexity of the fracture. The smaller the value of the communication coefficient, the smaller the potential for volume fracturing to form a complex fracture network, and the lower the complexity of the fracture.

[0056] Step 107: Classify the standard core according to the communication coefficient to determine the complexity of the fractures in the corresponding reservoir section. In the embodiment of the present application, the complexity of the reservoir section is divided into four levels according to the value of the communication coefficient, as follows: when 0 < communication coefficient ≤ 0.25, the level is IV, indicating that the fractures are not developed and the complexity is poor; when 0.25 < fracture communication coefficient ≤ 0.50, the level is III, indicating that the fractures are relatively developed and the complexity is medium; when 0.50 < fracture communication coefficient ≤ 0.75, the level is II, indicating that the fractures are developed and the complexity is high; when 0.75 < fracture communication coefficient ≤ 1.0, the level is I, indicating that the fractures are extremely developed and the complexity is extremely high.

[0057] The method disclosed in the present application can realize rapid evaluation of the complexity of fractures in any well in a mine, significantly reducing the costs of coring and microseismic monitoring in the mine. The method is simple and feasible, and is also applicable to similar shale gas reservoirs, and has good application prospects and promotion value.

[0058] The specific application process of the embodiment of the present application providing a method for evaluating the complexity of shale gas reservoir fractures is as follows.

[0059] WY is an evaluation well in the main development area of ​​a shale gas reservoir. The complexity of the fractures is particularly important for the evaluation of the complex fracture network formed by volume fracturing of horizontal wells in the WY area. Downhole coring was carried out in the main section of the reservoir where the WY well is located, and it was processed into standard cores. The mechanical parameters of the cores and each layer in them were obtained. The specific contents are as follows:

[0060] The core samples were processed into cylindrical standard cores with a diameter of 2.5 cm and a height of 5 cm. The Young's modulus and Poisson's ratio of each layer in the standard core were obtained, and a total of 16 layers (the middle section of the standard core) were obtained, and the values ​​of their Young's modulus and Poisson's ratio are shown in Table 1.

[0061] Table 1 Numerical table of layer Young's modulus and layer Poisson's ratio

[0062]

[0063] The Y barrier layer and the Y communication layer are divided by the layer Young's modulus, and the P barrier layer and the P communication layer are divided by the layer Poisson's ratio. Then, the layer Young's modulus and layer Poisson's ratio of each barrier layer and each communication layer are assigned values, and the assigned values ​​decrease from the communication layer to the barrier layer. The total mechanical parameter layer assignment is obtained by combining the assignment of the layer Young's modulus and the assignment of the layer Poisson's ratio. The specific contents are as follows: The middle section of the standard core with 16 beddings is obtained. In actual calculations, only the data of the middle 14 beddings (target beddings) except the top bedding and the bottom bedding are calculated.

[0064] The Y barrier layer and the Y communication layer are divided by the layer Young's modulus. The beddings with the maximum and minimum values ​​of the layer Young's modulus in the target bedding are divided into the first Y barrier layer and the first Y communication layer, respectively, and the layer Young's modulus of the first Y barrier layer is assigned to 1, and the layer Young's modulus of the first Y communication layer is assigned to 5. The layer Young's modulus of the target bedding is greater than the upper and lower adjacent beddings and is divided into the second Y barrier layer, and the layer Young's modulus of the second Y barrier layer is assigned to 2. The layer Young's modulus of the target bedding is less than the upper and lower adjacent beddings and is divided into the second Y communication layer, and the layer Young's modulus of the second Y communication layer is assigned to 4. The remaining undivided Y barrier layer and Y communication layer in the target bedding are divided into the third Y layer, and the layer Young's modulus of the third Y layer is assigned to 3. The results are shown in Table 2.

[0065] Table 2 Communication layer and barrier layer assignment table

[0066]

[0067] The P barrier layer and the P communication layer are divided by the layer Poisson's ratio. The beddings with the minimum and maximum values ​​of the Poisson's ratio in the target bedding are divided into the first P barrier layer and the first P communication layer, respectively. The layer Poisson's ratio of the first P barrier layer is assigned to 1, and the layer Poisson's ratio of the first P communication layer is assigned to 5. The bedding with a Poisson's ratio smaller than the upper and lower adjacent beddings in the target bedding is divided into the second P barrier layer, and the layer Poisson's ratio of the second P barrier layer is assigned to 2. The bedding with a Poisson's ratio larger than the upper and lower adjacent beddings in the target bedding is divided into the second P communication layer, and the layer Poisson's ratio of the second P communication layer is assigned to 4. The remaining undivided P barrier layer and P communication layer in the target bedding are divided into the third P layer, and the layer Poisson's ratio of the third P layer is assigned to 3. The results are shown in Table 2.

[0068] The total mechanical parameter layer assignment is calculated according to the sum of the layer Young's modulus assignment and the layer Poisson's ratio assignment in Table 2, and the layer mechanical index is calculated according to the ratio of the layer Young's modulus to the layer Poisson's ratio in Table 2, as shown in Table 3.

[0069] The total mechanical parameters are used to divide the Z barrier layer and the Z communication layer, and the bedding with the minimum value of the total mechanical parameter layer assignment is divided into the first Z barrier layer. The bedding with the smallest layer Young's modulus value is divided into the first Z communication layer. The bedding with a layer Young's modulus value greater than the upper and lower adjacent beddings is divided into the second Z barrier layer. The bedding with a layer Young's modulus value less than the upper and lower adjacent beddings is divided into the second Z communication layer. The remaining undivided Z barrier layer and Z communication layer are divided into the third Z layer. The layer weight coefficient is determined according to the above assignments. The degree of influence of beddings with different assignments on the communication ability is also different, as shown in Table 3.

[0070] Table 3 Assignment, layer mechanical index and layer weight coefficient table

[0071]

[0072] The communication coefficient is determined based on the layer weight coefficient, layer mechanical index and updated total mechanical parameter layer assignment. The final calculated communication coefficient result is 0.41, so the complexity level of the fractures in the reservoir section to be evaluated in Well WY is level III, the fractures are relatively developed and the complexity is medium.

[0073] Although the present application provides method operation steps as described in the embodiments or flowcharts, more or fewer operation steps may be included based on conventional or non-creative labor. The order of steps listed in this embodiment is only one way of executing the order of many steps and does not represent the only execution order. When the actual device or client product is executed, it can be executed in sequence or in parallel according to the method shown in this embodiment or the accompanying drawings (for example, in a parallel processor or multi-threaded processing environment).

[0074] like Figure 2 As shown, the embodiment of the present application also provides a shale gas reservoir fracture complexity evaluation device 200. The device includes: an acquisition module 201, a layer assignment module 202, a total mechanical parameter layer assignment module 203, a layer mechanical index module 204, a layer weight coefficient module 205, a communication coefficient module 206 and a complexity rating module 207, as follows.

[0075] The acquisition module 201 is used to acquire a standard core of a reservoir section, and acquire the Young's modulus and Poisson's ratio of each layer in the standard core.

[0076] The level assignment module 202 is used to divide the levels based on the layer Young's modulus and the layer Poisson's ratio, and update the assignment of each divided level.

[0077] The total mechanical parameter layer assignment module 203 is used to determine the total mechanical parameter layer assignment according to the assignments of each layer.

[0078] The layer mechanical index module 204 is used to determine the layer mechanical index according to the layer Young's modulus and the layer Poisson's ratio.

[0079] The layer weight coefficient module 205 is used to divide the Z layers based on the total mechanical parameter layer assignment, and determine the layer weight coefficient according to the total mechanical parameter layer assignment and the layer mechanical index of the divided Z layers.

[0080] The communication coefficient module 206 is used to determine the communication coefficient based on the layer weight coefficient, the layer mechanical index and the total mechanical parameter layer assignment.

[0081] The complexity rating module 207 is used to classify the standard cores according to the communication coefficient to determine the complexity of the fractures in the corresponding reservoir section.

[0082] Some modules in the apparatus described in the present application can be described in the general context of computer executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, classes, etc. that perform specific tasks or implement specific abstract data types. The present application can also be practiced in distributed computing environments, in which tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules can be located in local and remote computer storage media including storage devices.

[0083] The devices or modules described in the above application embodiments can be implemented by computer chips or entities, or by products with certain functions. For the convenience of description, the above devices are described in various modules according to their functions. When implementing the embodiments of the present application, the functions of each module can be implemented in the same or multiple software and / or hardware. Of course, the module that implements a certain function can also be implemented by combining multiple sub-modules or sub-units.

[0084] The methods, devices or modules described in this application can be implemented in the form of computer-readable program codes. The controller can be implemented in any appropriate manner. For example, the controller can take the form of a microprocessor or processor and a computer-readable medium storing computer-readable program codes (such as software or firmware) that can be executed by the (micro)processor, logic gates, switches, application-specific integrated circuits (English: Application Specific Integrated Circuit; Abbreviation: ASIC), programmable logic controllers and embedded microcontrollers. Examples of controllers include but are not limited to the following microcontrollers: ARC 625D, Atmel AT91SAM, Microchip PIC18F26K20 and Silicone Labs C8051F320. The memory controller can also be implemented as part of the control logic of the memory. Those skilled in the art also know that in addition to implementing the controller in the form of pure computer-readable program codes, the controller can be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers and embedded microcontrollers by logically programming the method steps. Therefore, this controller can be considered as a hardware component, and the devices included in it for implementing various functions can also be regarded as structures within the hardware component. Or even, the means for realizing various functions may be regarded as both a software module for realizing the method and a structure within a hardware component.

[0085] An embodiment of the present application further provides a device, comprising: a processor; a memory for storing processor executable instructions; when the processor executes the executable instructions, the method described in the embodiment of the present application is implemented.

[0086] The embodiments of the present application also provide a non-volatile computer-readable storage medium on which a computer program or instruction is stored. When the computer program or instruction is executed, the method described in the embodiments of the present application is implemented.

[0087] In addition, each functional module in each embodiment of the present invention may be integrated into one processing module, or each module may exist independently, or two or more modules may be integrated into one module.

[0088] The above storage media include but are not limited to random access memory (RAM), read-only memory (ROM), cache, hard disk drive (HDD) or memory card. The memory can be used to store computer program instructions.

[0089] It can be seen from the description of the above implementation methods that those skilled in the art can clearly understand that the present application can be implemented by means of software plus necessary hardware. Based on this understanding, the technical solution of the present application can be essentially or partly reflected in the prior art in the form of a software product, or it can be reflected in the implementation process of data migration. The computer software product can be stored in a storage medium, such as ROM / RAM, a magnetic disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a mobile terminal, a server, or a network device, etc.) to execute the methods described in the various embodiments of the present application or certain parts of the embodiments.

[0090] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. All or part of this application can be used in many general or special computer system environments or configurations. For example: personal computers, server computers, handheld devices or portable devices, tablet devices, mobile communication terminals, multi-processor systems, microprocessor-based systems, programmable electronic devices, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the above systems or devices, etc.

[0091] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present application.

Claims

1. A method for evaluating the complexity of shale gas reservoir fractures, characterized in that: include: Obtain standard cores of the reservoir section, and use ultrasonic method to obtain the Young's modulus and Poisson's ratio of each layer in the standard cores; The layers are divided based on the Young's modulus and the Poisson's ratio of the layers, and the values ​​of the divided layers are updated, including: based on the bedding structure of the standard core, the bedding other than the top layer and the bottom layer of the standard core is determined as the target bedding; within the target bedding, the communication layer and the barrier layer are divided based on the Young's modulus and the Poisson's ratio of the layers; the bedding within the target bedding is assigned values ​​in descending order from the communication layer to the barrier layer; Determine the total mechanical parameter layer assignment according to the assignment of each layer; determining a layer mechanical index based on the layer Young's modulus and the layer Poisson's ratio; Dividing the Z levels based on the total mechanical parameter layer assignment, and determining a layer weight coefficient according to the total mechanical parameter layer assignment and the layer mechanical index of the divided Z levels; Wherein, the Z level division based on the total mechanical parameter layer assignment includes: dividing the bedding where the minimum value of the total mechanical parameter layer assignment is located into the first Z barrier layer; dividing the bedding with the smallest value of the layer Young's modulus into the first Z communication layer; dividing the bedding with a value of the layer Young's modulus greater than the upper and lower adjacent beddings into the second Z barrier layer; dividing the bedding with a value of the layer Young's modulus less than the upper and lower adjacent beddings into the second Z communication layer; dividing the remaining undivided Z barrier layer and the Z communication layer into the third Z layer; The determining of the layer weight coefficient according to the total mechanical parameter layer assignment of the divided Z level and the layer mechanical index comprises: ； ； ； ； In the formula, is the layer mechanical index corresponding to the first Z communication layer, is the layer mechanical index corresponding to the second Z communication layer, is the layer mechanical index corresponding to the first Z barrier layer, is the layer mechanical index corresponding to the second Z barrier layer, is the layer weight coefficient of the first Z communication layer, is the layer weight coefficient of the second Z communication layer, is the layer weight coefficient of the first Z-blocking layer, is the layer weight coefficient of the second Z-blocking layer, is the layer mechanical index of bedding i within the target bedding, and n is the total number of target beddings in the standard core; Determining a communication coefficient based on the layer weight coefficient, the layer mechanical index and the total mechanical parameter layer assignment includes: ； Where K is the communication coefficient, is the layer weight coefficient of the first Z communication layer, is the layer mechanical index corresponding to the first Z communication layer, Assign the total mechanical parameter layer of the first Z communication layer, The first Z communication layer Layers, is the bedding number of the first Z communication layer, is the layer weight coefficient of the second Z communication layer, is the layer mechanical index corresponding to the second Z communication layer, Assign values ​​to the total mechanical parameter layer of the second Z communication layer, For the second Z communication layer Layers, is the bedding number of the second Z communication layer, is the layer weight coefficient of the first Z-blocking layer, is the layer mechanical index corresponding to the first Z barrier layer, Assign the total mechanical parameter layer of the first Z barrier layer, is the first Z barrier layer Layers, is the bedding number of the first Z barrier layer, is the layer weight coefficient of the second Z-blocking layer, is the layer mechanical index corresponding to the second Z barrier layer, Assign the total mechanical parameter layer of the second Z barrier layer, is the first Layers, is the bedding number of the second Z barrier layer, is the layer mechanical index of bedding i within the target bedding, Assign the total mechanical parameter layer of bedding i within the target bedding, n is the total number of target beddings in the standard core; The standard cores are classified according to the communication coefficients to determine the complexity of the fractures in the corresponding reservoir sections.

2. The method according to claim 1, characterized in that The dividing of the communication layer and the barrier layer based on the Young's modulus of the layer and the Poisson's ratio of the layer respectively comprises: The beddings where the maximum value and the minimum value of the layer Young's modulus in the target bedding are located are respectively divided into a first Y barrier layer and a first Y communication layer; The target bedding layer whose Young's modulus is greater than the upper and lower adjacent bedding layers is divided into a second Y barrier layer; The target bedding layer whose Young's modulus is smaller than the upper and lower adjacent bedding layers is divided into a second Y communication layer; dividing the remaining undivided bedding in the target bedding into a third Y layer; The beddings where the minimum and maximum values ​​of the layer Poisson's ratio of the target bedding are located are respectively divided into a first P barrier layer and a first P communication layer; Classify the target bedding layer whose Poisson's ratio is smaller than that of the upper and lower adjacent bedding layers as a second P barrier layer; The target bedding layer having a Poisson's ratio greater than that of two upper and lower adjacent bedding layers is divided into a second P communication layer; The remaining undivided beddings in the target bedding are divided into a third P layer.

3. The method according to claim 2, characterized in that The step of assigning values ​​of the layers in the target layer in descending order from the communication layer to the barrier layer includes: assigning the layer Young's modulus of the first Y barrier layer and the layer Poisson's ratio of the first P barrier layer to a first value; assigning the layer Young's modulus of the first Y communication layer and the layer Poisson's ratio of the first P communication layer to a fifth value; assigning the layer Young's modulus of the second Y barrier layer and the layer Poisson's ratio of the second P barrier layer to a second value; assigning the layer Young's modulus of the second Y communication layer and the layer Poisson's ratio of the second P communication layer to a fourth value; assigning the layer Young's modulus of the third Y layer and the layer Poisson's ratio of the third P layer to a third value; Among them, the first value < the second value < the third value < the fourth value < the fifth value.

4. The method according to claim 1, characterized in that Determining the total mechanical parameter layer assignment according to the assignment of each level includes: ； In the formula, Assign the total mechanical parameter layer of bedding i within the target bedding, is the value of Young's modulus of layer i in the target layer, Assignment of the Poisson's ratio of layer i within the target bedding.

5. The method according to claim 1, characterized in that Determining the layer mechanical index according to the layer Young's modulus and the layer Poisson's ratio comprises: ； In the formula, is the layer mechanical index of bedding i within the target bedding, is the Young's modulus of layer i in the target layer, is the Poisson’s ratio of layer i in the target bedding.

6. A device for evaluating the complexity of shale gas reservoir fractures based on the method according to any one of claims 1 to 5, characterized in that: include: An acquisition module is used to acquire a standard core of a reservoir section and to acquire the Young's modulus and Poisson's ratio of each layer in the standard core by using an ultrasonic method; The layer assignment module is used to divide the layers based on the layer Young's modulus and the layer Poisson's ratio, and update the assignment of each divided layer, including: based on the bedding structure of the standard core, determining the bedding other than the top layer and the bottom layer of the standard core as the target bedding; within the target bedding, dividing the communication layer and the barrier layer based on the layer Young's modulus and the layer Poisson's ratio; assigning the bedding within the target bedding in descending order from the communication layer to the barrier layer; A total mechanical parameter layer assignment module is used to determine the total mechanical parameter layer assignment according to the assignments of each layer; a layer mechanical index module, for determining a layer mechanical index according to the layer Young's modulus and the layer Poisson's ratio; A layer weight coefficient module is used to divide the Z layer based on the total mechanical parameter layer assignment, and determine the layer weight coefficient according to the total mechanical parameter layer assignment and the layer mechanical index of the divided Z layer; wherein, the division of the Z layer based on the total mechanical parameter layer assignment includes: dividing the bedding where the minimum value of the total mechanical parameter layer assignment is located into the first Z barrier layer; dividing the bedding with the smallest value of the layer Young's modulus into the first Z communication layer; dividing the bedding with a value of the layer Young's modulus greater than the upper and lower adjacent bedding into the second Z barrier layer; dividing the bedding with a value of the layer Young's modulus less than the upper and lower adjacent bedding into the second Z communication layer; dividing the remaining undivided Z barrier layer and Z communication layer into the third Z layer; The determining of the layer weight coefficient according to the total mechanical parameter layer assignment of the divided Z level and the layer mechanical index comprises: ； ； ； ； In the formula, is the layer mechanical index corresponding to the first Z communication layer, is the layer mechanical index corresponding to the second Z communication layer, is the layer mechanical index corresponding to the first Z barrier layer, is the layer mechanical index corresponding to the second Z barrier layer, is the layer weight coefficient of the first Z communication layer, is the layer weight coefficient of the second Z communication layer, is the layer weight coefficient of the first Z-blocking layer, is the layer weight coefficient of the second Z-blocking layer, is the layer mechanical index of bedding i within the target bedding, and n is the total number of target beddings in the standard core; A communication coefficient module, used to determine the communication coefficient based on the layer weight coefficient, the layer mechanical index and the total mechanical parameter layer assignment, includes: ； Where K is the communication coefficient, is the layer weight coefficient of the first Z communication layer, is the layer mechanical index corresponding to the first Z communication layer, Assign the total mechanical parameter layer of the first Z communication layer, The first Z communication layer Layers, is the bedding number of the first Z communication layer, is the layer weight coefficient of the second Z communication layer, is the layer mechanical index corresponding to the second Z communication layer, Assign values ​​to the total mechanical parameter layer of the second Z communication layer, For the second Z communication layer Layers, is the bedding number of the second Z communication layer, is the layer weight coefficient of the first Z-blocking layer, is the layer mechanical index corresponding to the first Z barrier layer, Assign the total mechanical parameter layer of the first Z barrier layer, is the first Z barrier layer Layers, is the bedding number of the first Z barrier layer, is the layer weight coefficient of the second Z-blocking layer, is the layer mechanical index corresponding to the second Z barrier layer, Assign the total mechanical parameter layer of the second Z barrier layer, is the first Layers, is the bedding number of the second Z barrier layer, is the layer mechanical index of bedding i within the target bedding, Assign the total mechanical parameter layer of bedding i within the target bedding, n is the total number of target beddings in the standard core; The complexity rating module is used to classify the standard core according to the communication coefficient to determine the complexity of the fractures in the corresponding reservoir section.

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