Method, device, storage medium and electronic equipment for evaluating the difficulty of shale formation development

Abstract

The application relates to the technical field of oil exploration and development, in particular to a method and device for evaluating development difficulty of a shale formation, a storage medium and an electronic device, which comprise the following steps: obtaining geological sweet spot parameters and open flow capacity, and calculating a geological sweet spot coefficient; calculating potential benefits according to the geological sweet spot coefficient and initial gas production; generating a potential benefit curve diagram according to different geological sweet spot coefficients and respective corresponding potential benefits; calculating an engineering sweet spot coefficient according to engineering sweet spot parameters and sand-carrying ratios; calculating development costs according to the engineering sweet spot coefficient; generating a development cost curve diagram according to different engineering sweet spot coefficients and respective corresponding development costs; and obtaining a marginal exploitable sweet spot coefficient according to the two curve diagrams to evaluate the development difficulty of the shale formation. The marginal exploitable sweet spot coefficient is obtained through the geological sweet spot coefficient and the engineering sweet spot coefficient, development benefits and costs of the shale formation are evaluated, and whether the shale formation has mining value and the development difficulty degree are determined.

Description

Technical Field

[0001] The present application relates to the technical field of petroleum exploration and development, and in particular to a method, device, storage medium and electronic device for evaluating the difficulty of shale formation development. Background Art

[0002] The "sweet spots" in shale formations are areas with good reservoir geology and amenability to fracturing. These sweet spots are crucial for shale development, as identifying them can help reduce shale exploration and development costs and increase the productivity of gas-bearing shale formations.

[0003] Among the existing methods for assessing the difficulty of shale formation development, Cipolla uses reservoir quality parameters to illustrate the gas recoverability of shale formations. The usual practice is to use geostatistical methods to describe the "sweet spots": parameters such as brittle mineral content, porosity, thermal maturity, organic matter content, net thickness, burial depth, gas content, and water saturation of the shale formation. However, these parameters do not distinguish between geological sweet spot parameters and engineering sweet spot parameters, nor do they distinguish between the weights of each parameter.

[0004] It can be seen that the existing technology does not analyze the recoverability of the shale formation from the perspective of the overall development of the shale formation. Summary of the Invention

[0005] In response to the above problems, the present application provides a method, device, storage medium and electronic equipment for evaluating the difficulty of shale formation development, which solves the technical problem in the related art that the recoverability of the formation is not analyzed from the perspective of the overall development of the shale formation.

[0006] In a first aspect, the present application provides a method for assessing the difficulty of shale formation development, the method comprising:

[0007] Collect geological sweet spot parameters of target shale formation and open flow rate of initial gas production test;

[0008] Calculating a geological sweet spot coefficient according to the geological sweet spot parameters and the open flow rate;

[0009] Calculate and predict the initial gas production based on the geological sweet spot coefficient;

[0010] calculating potential benefits based on current oil and gas prices and discount rates, the predicted initial gas production, and the gas production decline rate of the target shale formation;

[0011] Generate a potential benefit curve based on different geological sweet spot coefficients and their corresponding potential benefits;

[0012] Collect engineering sweet spot parameters and sand carrying ratio of target shale formation;

[0013] Calculating an engineering sweet spot coefficient according to the engineering sweet spot parameters and the sand carrying ratio;

[0014] Calculating the development cost based on the engineering sweet spot coefficient;

[0015] Generate a development cost curve based on different engineering sweet spot coefficients and their corresponding development costs;

[0016] Obtaining a marginal sweet spot coefficient according to the potential benefit curve and the development cost curve;

[0017] The difficulty of developing the target shale formation is determined based on the marginal recoverable sweet spot coefficient.

[0018] In some embodiments, calculating the geological sweet spot coefficient according to the geological sweet spot parameter and the open flow rate includes:

[0019] Calculating a correlation coefficient between the geological sweet spot parameter and the open flow rate according to the geological sweet spot parameter and the open flow rate;

[0020] Selecting a geological sweet spot parameter corresponding to a correlation coefficient greater than a first preset threshold as a main geological sweet spot parameter;

[0021] Calculate the multiple correlation coefficients of each major geological sweet spot parameter with other geological sweet spot parameters;

[0022] The correlation coefficient of each major geological sweet spot parameter is divided by its respective multiple correlation coefficient, and the obtained results are normalized to obtain the weight of each major geological sweet spot parameter;

[0023] According to the formula X G =∑W' i X i Calculating the geological sweet spot coefficient of the target shale formation;

[0024] Among them, X G is the geological sweet spot coefficient, W' i is the weight, X i is the parameter of the i-th main geological sweet spot.

[0025] In some embodiments, the calculating and predicting the initial gas production according to the geological sweet spot coefficient includes:

[0026] The initial gas production prediction regression equation is constructed based on the historical geological sweet spot coefficient and its corresponding historical initial gas production;

[0027] The predicted initial gas production is calculated based on the initial gas production prediction regression equation and the geological sweet spot coefficient.

[0028] In some embodiments, the potential benefits are calculated based on current oil and gas prices and discount rates, the predicted initial gas production, and the gas production decline rate of the target shale formation, including:

[0029] According to the predicted initial gas production, the current oil and gas price and discount rate, and the gas production attenuation rate of the target shale formation, the formula:

[0030]

[0031] Calculate the total future cash benefit value E, i.e. the potential benefit;

[0032] Among them, E0=y*p, y is the predicted initial gas production, p is the oil and gas price, d1 is the gas production attenuation rate, d2 is the discount rate, and n is the mining life.

[0033] In some embodiments, calculating the engineering sweet spot coefficient according to the engineering sweet spot parameter and the sand carrying ratio includes:

[0034] Calculating the correlation coefficient between the engineering sweet spot parameter and the sand carrying ratio according to the engineering sweet spot parameter and the sand carrying ratio;

[0035] Selecting an engineering sweet spot parameter corresponding to a correlation coefficient greater than a second preset threshold as a main engineering sweet spot parameter;

[0036] Calculate the complex correlation coefficient between each main engineering sweet spot parameter and other engineering sweet spot parameters;

[0037] Divide the correlation coefficient of each main engineering sweet spot parameter by its respective multiple correlation coefficient, and normalize the obtained results to obtain the weight of each main engineering sweet spot parameter;

[0038] According to the formula X E =∑W' i X i Calculating the engineering sweet spot coefficient of the target shale formation;

[0039] Among them, X E is the engineering sweet spot coefficient, W' i is the weight, X i is the i-th main engineering sweet spot parameter.

[0040] In some embodiments, calculating the development cost based on the engineering sweet spot coefficient includes:

[0041] Calculating the fracturing production cost according to the engineering sweet spot coefficient;

[0042] The development cost is obtained by adding the fracturing production cost and the drilling and completion cost of the target shale formation.

[0043] In some embodiments, collecting the sand carrying ratio of a target shale formation includes:

[0044] Collect the total sand addition and fluid injection volumes during the fracturing process of the target shale formation;

[0045] The sand carrying ratio is calculated based on the sand addition amount and the liquid injection amount.

[0046] In some embodiments, obtaining the marginal sweet spot coefficient according to the potential benefit curve and the development cost curve includes:

[0047] Placing the potential benefit curve and the development cost curve in the same coordinate system;

[0048] The intersection of the potential benefit curve and the development cost curve for the preset years is taken as the marginal sweet spot coefficient.

[0049] In a second aspect, a device for assessing the difficulty of shale formation development is provided, the device comprising:

[0050] The first acquisition unit is used to collect the geological sweet spot parameters of the target shale formation and the open flow rate of the initial gas production test;

[0051] A first calculation unit is used to calculate a geological sweet spot coefficient according to the geological sweet spot parameter and the open flow rate;

[0052] a second calculation unit, configured to calculate a predicted initial gas production according to the geological sweet spot coefficient; and calculate potential benefits according to current oil and gas prices and discount rates, the predicted initial gas production, and the gas production attenuation rate of the target shale formation;

[0053] The first generating unit is used to generate a potential benefit curve according to different geological sweet spot coefficients and their corresponding potential benefits;

[0054] The second acquisition unit is used to collect the engineering sweet spot parameters and sand carrying ratio of the target shale formation;

[0055] A third calculation unit is used to calculate the engineering sweet spot coefficient according to the engineering sweet spot parameter and the sand carrying ratio;

[0056] a fourth calculation unit, configured to calculate a development cost according to the engineering sweet spot coefficient and the sand carrying ratio;

[0057] The second generating unit is used to generate a development cost curve according to different engineering sweet spot coefficients and their corresponding development costs;

[0058] an acquisition unit, configured to obtain a marginal sweet spot coefficient according to the potential benefit curve and the development cost curve;

[0059] A judgment unit is used to judge the development difficulty of the target shale formation according to the marginal recoverable sweet spot coefficient.

[0060] In a third aspect, a storage medium stores a computer program that can be executed by one or more processors and can be used to implement the method for assessing the difficulty of shale formation development as described in the first aspect.

[0061] In a fourth aspect, an electronic device includes a memory and a processor, wherein a computer program is stored in the memory, and the memory and the processor are communicatively connected to each other. When the computer program is executed by the processor, the method for assessing the difficulty of shale formation development as described in the first aspect above is performed.

[0062] The present application provides a method, device, storage medium, and electronic device for assessing the difficulty of shale formation development, including: collecting geological sweet spot parameters and the open flow rate of initial gas production test of a target shale formation; calculating a geological sweet spot coefficient based on the geological sweet spot parameters and the open flow rate; calculating a predicted initial gas production rate based on the geological sweet spot coefficient; calculating potential benefits based on current oil and gas prices and discount rates, the predicted initial gas production rate, and the gas production attenuation rate of the target shale formation; generating a potential benefit curve based on different geological sweet spot coefficients and their corresponding potential benefits; collecting engineering sweet spot parameters and a sand-carrying ratio of the target shale formation; calculating an engineering sweet spot coefficient based on the engineering sweet spot parameters and the sand-carrying ratio; calculating development costs based on the engineering sweet spot coefficient; generating a development cost curve based on different engineering sweet spot coefficients and their corresponding development costs; obtaining a marginal recoverable sweet spot coefficient based on the potential benefit curve and the development cost curve; and determining the difficulty of developing the target shale formation based on the marginal recoverable sweet spot coefficient. The geological sweet spot coefficient reflects the initial gas production rate and potential benefits, while the engineering sweet spot coefficient reflects the fracturing scale and fracturing cost. This application obtains the marginal mineable sweet spot coefficient through the geological sweet spot coefficient and the engineering sweet spot coefficient, realizes the development benefit and cost evaluation of the shale formation, and at the same time determines whether the shale formation has mining value and the difficulty of development. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0064] Figure 1 A schematic flow chart of a method for evaluating the difficulty of shale formation development provided in an embodiment of the present application;

[0065] Figure 2 A schematic diagram of a potential benefit curve provided for an embodiment of the present application;

[0066] Figure 3 A schematic diagram of a development cost curve provided for an embodiment of the present application;

[0067] Figure 4 A schematic diagram of the marginal harvestable sweet spot provided in an embodiment of the present application;

[0068] Figure 5 A graph showing the relationship between geological sweet spot parameters and gas production provided in the embodiments of this application;

[0069] Figure 6 A graph showing the relationship between the engineering sweet spot coefficient and the sand carrying ratio provided in the embodiments of this application;

[0070] Figure 7 A curve chart of the recovery and development costs provided in the embodiments of this application;

[0071] Figure 8 A schematic diagram of the structure of a device for assessing the difficulty of shale formation development provided in an embodiment of the present application;

[0072] Figure 9 A connection block diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0073] The following will describe the implementation methods of this application in detail with reference to the accompanying drawings and examples, so that the application can fully understand how technical means are used to solve technical problems and achieve corresponding technical effects, and implement them accordingly. The embodiments of this application and the various features therein can be combined with each other without conflict, and the resulting technical solutions are all within the scope of protection of this application.

[0074] As can be seen from the background technology, among the existing methods for assessing the difficulty of shale formation development, Cipolla uses reservoir quality parameters to illustrate the gas recoverability of shale formations. The usual practice is to use geostatistical methods to describe the "sweet spots": parameters such as brittle mineral content, porosity, thermal maturity, organic matter content, net thickness, burial depth, gas content and water saturation of the shale formation. However, these parameters do not distinguish between geological sweet spot parameters and engineering sweet spot parameters, nor do they distinguish between the weights of each parameter.

[0075] It can be seen that the existing technology does not analyze the recoverability of the shale formation from the perspective of the overall development of the shale formation.

[0076] In view of this, the present application provides a method, device, storage medium and electronic equipment for evaluating the difficulty of shale formation development, which solves the technical problem in the related art that the recoverability of the formation is not analyzed from the perspective of the overall development of the shale formation.

[0077] Example 1

[0078] Figure 1 A flow chart of a method for evaluating the difficulty of shale formation development provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, the method includes:

[0079] S101. Collect the geological sweet spot parameters of the target shale formation and the open flow rate of the initial gas production test.

[0080] It should be noted that the geological sweet spot parameters can be collected from the well logging interpretation of the target shale formation, and the geological sweet spot parameters include mud content, silica content, carbon content, organic matter content, kerogen content, porosity, water saturation and pore pressure.

[0081] S102: Calculate a geological sweet spot coefficient according to the geological sweet spot parameters and the open flow rate.

[0082] It should be noted that the geological sweet spot coefficient reflects the initial gas production and potential benefits. The geological sweet spot coefficient can be used to evaluate the development benefits of shale formations and determine whether the shale formation has mining value.

[0083] Preferably, the calculating of the geological sweet spot coefficient according to the geological sweet spot parameters and the open flow rate includes:

[0084] Calculating a correlation coefficient between the geological sweet spot parameter and the open flow rate according to the geological sweet spot parameter and the open flow rate;

[0085] Selecting a geological sweet spot parameter corresponding to a correlation coefficient greater than a first preset threshold as a main geological sweet spot parameter;

[0086] Calculate the multiple correlation coefficients of each major geological sweet spot parameter with other geological sweet spot parameters;

[0087] The correlation coefficient of each major geological sweet spot parameter is divided by its respective multiple correlation coefficient, and the obtained results are normalized to obtain the weight of each major geological sweet spot parameter;

[0088] According to the formula X G =∑W' i X i Calculating the geological sweet spot coefficient of the target shale formation;

[0089] Among them, X G is the geological sweet spot coefficient, W' i is the weight, X i is the parameter of the i-th main geological sweet spot.

[0090] It should be noted that the correlation coefficient between the geological sweet spot parameters and the open flow rate can be calculated by the correlation coefficient method.

[0091] The correlation coefficient method is to determine the importance and role of indicators based on the strength of collinearity between each indicator and the output indicator. Suppose indicator items X1, X2, ..., X n , if the indicator X i The larger the correlation coefficient with the output index, the better the X i The stronger the collinearity between the indicator and the output indicator, the greater the influence of the indicator on the output indicator should be. The formula for calculating the correlation coefficient is:

[0092]

[0093] Where COV(X,Y) is the covariance of X and Y, D(X) is the variance of X, and D(Y) is the variance of Y.

[0094] Therefore, when calculating the geological correlation coefficient, the geological sweet spot parameter is taken as X and the open flow rate is taken as Y. The correlation coefficient between each geological sweet spot parameter and the open flow rate is calculated.

[0095] Then, the correlation coefficients are sorted from large to small, and the geological sweet spot parameters corresponding to the correlation coefficients greater than the first preset threshold are selected as the main geological sweet spot parameters, wherein the first preset threshold is not fixed and can be appropriately adjusted according to needs.

[0096] It should be further explained that if a correlation coefficient is negative, the correlation coefficient needs to be corrected.

[0097] Specifically, after taking the absolute value of the negative correlation coefficient, it is added to other correlation coefficients for sorting.

[0098] Then the multiple correlation coefficients of each main geological sweet spot parameter and other geological sweet spot parameters were calculated according to the independence weight coefficient method.

[0099] The vertical weight coefficient method determines the weight of the indicator according to the strength of the collinearity between each indicator and other indicators. Suppose the indicator items X1, X2, ..., X m , if the indicator X k The larger the multiple correlation coefficient with other indicators, the more k The stronger the collinearity relationship with other indicators, the easier it is to be represented by a linear combination of other indicators, the more repeated information there is, and therefore the smaller the weight of the indicator.

[0100] That is, if the indicator X k The larger the multiple correlation coefficient with other indicators, the smaller the weight of the indicator. The calculation formula of the multiple correlation coefficient is:

[0101]

[0102] Among them, X is the index value; is the average value of all indicators; is the expected value of X, CR i is the multiple correlation coefficient.

[0103] Therefore, when calculating the complex correlation coefficient, the main geological sweet spot parameter is X, is the average value of all geological sweet spot parameters, is the expected value of the main physical sweet spot parameter X, which is substituted into the formula to calculate the complex correlation coefficient between each main geological sweet spot parameter and other geological sweet spot parameters.

[0104] The correlation coefficient of each major geological sweet spot parameter was then divided by the respective geological multiple correlation coefficient, and the obtained results were normalized to obtain the weight of each major geological sweet spot parameter.

[0105] Specifically, we can first calculate the inverse of the complex correlation coefficient 1 / CR of each main geological sweet spot parameter and other geological sweet spot parameters i , and then the correlation coefficient R of each main geological sweet spot parameter is i Multiply by the inverse of the respective multiple correlation coefficients 1 / CR i , and obtain the calculation result comprehensive coefficient W i =R i / CR i .

[0106] Then the comprehensive coefficient W of each main geological sweet spot parameter is i Perform normalization processing, the normalization formula is:

[0107]

[0108] Among them, W i ' is the weight coefficient of the main geological sweet spot parameters, W i is the comprehensive coefficient of the i-th main geological sweet spot parameter, n is the total number of main geological sweet spot parameters, and i and n are positive integers.

[0109] After calculating the weight coefficient of each major geological sweet spot parameter, according to the formula X G =∑W' i X i The geological sweet spot coefficient of the target shale formation is calculated.

[0110] Among them, X G is the geological sweet spot coefficient, W' i is the weight coefficient of the main geological sweet spot parameters, X iis the parameter of the i-th main geological sweet spot.

[0111] S103: Calculate and predict the initial gas production according to the geological sweet spot coefficient.

[0112] Preferably, the calculating and predicting the initial gas production according to the geological sweet spot coefficient includes:

[0113] The initial gas production prediction regression equation is constructed based on the historical geological sweet spot coefficient and its corresponding historical initial gas production;

[0114] The predicted initial gas production is calculated based on the initial gas production prediction regression equation and the geological sweet spot coefficient.

[0115] It should be noted that the initial gas production prediction regression equation is constructed based on the historical geological sweet spot coefficient and its corresponding initial gas production: y = ax b , where x is the geological sweet spot coefficient, y is the initial gas production, and a and b are the regression coefficients determined by the regression algorithm.

[0116] S104. Calculate potential benefits based on the current oil and gas price and discount rate, the predicted initial gas production, and the gas production attenuation rate of the target shale formation.

[0117] Preferably, the calculating of potential benefits based on the current oil and gas price and discount rate, the predicted initial gas production, and the gas production attenuation rate of the target shale formation includes:

[0118] According to the predicted initial gas production, the current oil and gas price and discount rate, and the gas production attenuation rate of the target shale formation, the formula:

[0119]

[0120] Calculate the total future cash benefit value E, i.e. the potential benefit;

[0121] Among them, E0=y*p, y is the predicted initial gas production, p is the oil and gas price, d1 is the gas production attenuation rate, d2 is the discount rate, and n is the mining life.

[0122] It should be noted that, as can be seen from the potential benefit formula, the factors affecting potential benefits include initial gas production y, gas production attenuation rate d1, oil and gas price p and discount rate d2, and the total benefit value will be different with different mining years n. Among them, the gas production attenuation rate d1, oil and gas price p and discount rate d2 are obtained from actual production data. n is usually calculated as 10 years, but it is not fixed and can be adjusted and modified appropriately as production data increases or actual conditions and needs change.

[0123] S105. Generate a potential benefit curve according to different geological sweet spot coefficients and their corresponding potential benefits.

[0124] Specifically, a rectangular coordinate system is established with the geological sweet spot coefficient as the x-coordinate and the potential benefit as the y-coordinate, and the calculated geological sweet spot coefficient and the corresponding potential benefit are marked in the rectangular coordinate system to obtain a potential benefit curve.

[0125] like Figure 2 As shown, it is a schematic diagram of the potential benefit curve in another embodiment of the present application, wherein the geological sweet spot coefficient is used as the x-coordinate and the potential benefit is used as the y-coordinate, and multiple potential benefit curves are drawn according to different mining years, including the 1st to the 20th year.

[0126] S106. Collect engineering sweet spot parameters and sand carrying ratio of the target shale formation.

[0127] It should be noted that the engineering sweet spot parameters can be collected from the well logging interpretation of the target shale formation. The engineering sweet spot parameters include mud content Vs, silica content Vq, carbon content Vc, brittleness index Brit, fracture pressure Pp, pore pressure Pf and stress difference coefficient Δσ.

[0128] Preferably, the sand carrying ratio of the target shale formation is collected, including:

[0129] Collect the total sand addition and fluid injection volumes during the fracturing process of the target shale formation;

[0130] The sand carrying ratio is calculated based on the sand addition amount and the liquid injection amount.

[0131] Specifically, the total amount of sand added during the shale formation fracturing process F is collected. sand and injection volume F fluid , calculate the sand carrying ratio, where sand carrying ratio = F sand / F fluid *100.

[0132] S107. Calculate the engineering sweet spot coefficient according to the engineering sweet spot parameters and the sand carrying ratio.

[0133] It should be noted that the engineering sweet spot coefficient reflects the scale and cost of fracturing. The engineering sweet spot coefficient can be used to evaluate the development cost of shale formations and determine the difficulty of developing the shale formations.

[0134] Preferably, the calculation of the engineering sweet spot coefficient according to the engineering sweet spot parameters and the sand carrying ratio includes:

[0135] Calculating the correlation coefficient between the engineering sweet spot parameter and the sand carrying ratio according to the engineering sweet spot parameter and the sand carrying ratio;

[0136] Selecting an engineering sweet spot parameter corresponding to a correlation coefficient greater than a second preset threshold as a main engineering sweet spot parameter;

[0137] Calculate the complex correlation coefficient between each main engineering sweet spot parameter and other engineering sweet spot parameters;

[0138] Divide the correlation coefficient of each main engineering sweet spot parameter by its respective multiple correlation coefficient, and normalize the obtained results to obtain the weight of each main engineering sweet spot parameter;

[0139] According to the formula X E =∑W' i X i Calculating the engineering sweet spot coefficient of the target shale formation;

[0140] Among them, X E is the engineering sweet spot coefficient, W' i is the weight, X i is the i-th main engineering sweet spot parameter.

[0141] It should be noted that the correlation coefficient between the engineering sweet spot parameters and the sand carrying ratio can be calculated by the correlation coefficient method.

[0142] The correlation coefficient method is to determine the importance and role of indicators based on the strength of collinearity between each indicator and the output indicator. Suppose indicator items X1, X2, ..., X n , if the indicator X i The larger the correlation coefficient with the output index, the better the X i The stronger the collinearity between the indicator and the output indicator, the greater the influence of the indicator on the output indicator should be. The formula for calculating the correlation coefficient is:

[0143]

[0144] Where COV(X,Y) is the covariance of X and Y, D(X) is the variance of X, and D(Y) is the variance of Y.

[0145] Therefore, when calculating the correlation coefficient, the engineering sweet spot parameter is taken as X and the sand carrying ratio is taken as Y, and the correlation coefficient between each engineering sweet spot parameter and the sand carrying ratio is calculated.

[0146] Then, the correlation coefficients are sorted from large to small, and the engineering sweet spot parameters corresponding to the correlation coefficients greater than the second preset threshold are selected as the main engineering sweet spot parameters, wherein the second preset threshold is not fixed and can be appropriately adjusted according to needs.

[0147] It should be further explained that if a correlation coefficient is negative, the correlation coefficient needs to be corrected.

[0148] Specifically, after taking the absolute value of the negative correlation coefficient, it is added to other correlation coefficients for sorting.

[0149] Then, the multiple correlation coefficients of each main engineering sweet spot parameter and other engineering sweet spot parameters are calculated according to the independence weight coefficient method.

[0150] The vertical weight coefficient method determines the weight of the indicator according to the strength of the collinearity between each indicator and other indicators. Suppose the indicator items X1, X2, ..., X m , if the indicator X k The larger the multiple correlation coefficient with other indicators, the more k The stronger the collinearity relationship with other indicators, the easier it is to be represented by a linear combination of other indicators, the more repeated information there is, and therefore the smaller the weight of the indicator.

[0151] That is, if the indicator X k The larger the multiple correlation coefficient with other indicators, the smaller the weight of the indicator. The calculation formula of the multiple correlation coefficient is:

[0152]

[0153] Among them, X is the index value; is the average value of all indicators; is the expected value of X, CR i is a negative correlation coefficient.

[0154] Therefore, when calculating the complex correlation coefficient, the main engineering sweet spot parameter is X, is the average value of all engineering sweet spot parameters, is the expected value of the main physical sweet spot parameter X, which is substituted into the formula to calculate the complex correlation coefficient between each main engineering sweet spot parameter and other engineering sweet spot parameters.

[0155] The correlation coefficient of each main engineering sweet spot parameter is then divided by its respective multiple correlation coefficient, and the obtained results are normalized to obtain the weight of each main engineering sweet spot parameter.

[0156] Specifically, we can first calculate the inverse of the complex correlation coefficient 1 / CR of each main engineering sweet spot parameter and other engineering sweet spot parameters. i , and then the correlation coefficient R of each main engineering sweet spot parameter i Multiply by the inverse of the respective multiple correlation coefficients 1 / CR i , and obtain the calculation result comprehensive coefficient W i =R i / CR i .

[0157] Then the comprehensive coefficient W of each main engineering sweet spot parameter is iPerform normalization processing, the normalization formula is:

[0158]

[0159] Among them, W i ' is the weight coefficient of the main engineering sweet spot parameters, W i is the comprehensive coefficient of the i-th main engineering sweet spot parameter, n is the total number of main engineering sweet spot parameters, and i and n are positive integers.

[0160] After calculating the weight coefficient of each main engineering sweet spot parameter, according to the formula X E =∑W' i X i The engineering sweet spot coefficient of the target shale formation is calculated.

[0161] Among them, X E is the engineering sweet spot coefficient, W' i is the weight coefficient of the main engineering sweet spot parameters, X i is the i-th main engineering sweet spot parameter.

[0162] S108. Calculate the development cost according to the engineering sweet spot coefficient.

[0163] Preferably, the calculation of the development cost according to the engineering sweet spot coefficient includes:

[0164] Calculating the fracturing production cost according to the engineering sweet spot coefficient;

[0165] The development cost is obtained by adding the fracturing production cost and the drilling and completion cost of the target shale formation.

[0166] Specifically, according to the formula y2=a2+b2(c-dln(X E )) e Calculate the development cost y2.

[0167] Among them, y2 is the development cost; X E is the engineering sweet spot coefficient; a2 is the known drilling and completion cost; b2(c-ln(X E )) e is the cost of fracturing production; b2, c, d, e are the regression coefficients determined by the regression algorithm.

[0168] S109. Generate a development cost curve according to different engineering sweet spot coefficients and their corresponding development costs.

[0169] Specifically, a rectangular coordinate system is established with the engineering sweet spot coefficient as the x-coordinate and the development cost as the y-coordinate, and the calculated engineering sweet spot coefficient and the corresponding development cost are marked in the rectangular coordinate system to obtain a development cost curve.

[0170] like Figure 3 As shown, it is a schematic diagram of the development cost curve in another embodiment of the present application, wherein the engineering sweet spot coefficient is used as the x-coordinate and the development cost is used as the y-coordinate to draw the development cost curve.

[0171] S110. Obtain a marginal sweet spot coefficient according to the potential benefit curve and the development cost curve.

[0172] Preferably, obtaining the marginal sweet spot coefficient according to the potential benefit curve and the development cost curve includes:

[0173] Placing the potential benefit curve and the development cost curve in the same coordinate system;

[0174] The intersection of the potential benefit curve and the development cost curve for the preset years is taken as the marginal sweet spot coefficient.

[0175] It should be noted that since the potential benefits and development costs are both monetary values, the geological sweet spot coefficient and the engineering sweet spot coefficient are also the same type of coefficients. Therefore, as long as the x-coordinate of the new coordinate system is set to the sweet spot coefficient and the y-coordinate is set to the monetary value, the potential benefit curve and the development cost curve can be placed in the same coordinate system.

[0176] S111. Determine the difficulty of developing the target shale formation according to the marginal recoverable sweet spot coefficient.

[0177] Specifically, such as Figure 4 As shown, it is a schematic diagram of the marginal recoverable sweet spot disclosed in another embodiment of the present application. Among them, the marginal recoverable sweet spot represents the sweet spot coefficient where the potential income corresponding to the geological sweet spot coefficient of the shale formation and the development cost corresponding to the engineering sweet spot coefficient are equal. The difficulty of shale formation development is judged according to the sweet spot coefficient value corresponding to the marginal recoverable sweet spot: the higher the marginal recoverable sweet spot value, the higher the development cost, the more difficult the development, and the smaller the development benefit; the lower the marginal recoverable sweet spot value, the smaller the development cost, the easier the development, and the greater the development benefit. Generally speaking, when the marginal recoverable sweet spot value is greater than 0.6, it means that the shale formation is difficult to develop; when the marginal recoverable sweet spot value is less than 0.4, it means that the formation development difficulty is relatively low; when the marginal recoverable sweet spot value is between 0.4-0.6, the difficulty of shale formation development is at a medium level. For example, Figure 4 The sweet spot coefficient corresponding to the marginal recoverable sweet spot is about 0.41, which is between 0.4 and 0.6, indicating that the difficulty of shale formation development is at a medium level.

[0178] It should be noted that sometimes the marginal recoverable sweet spot cannot be obtained in shale formations, but the difference between the potential benefit curve and the development cost curve represents the development benefit. When the marginal sweet spot is larger, the development benefit is smaller and the development difficulty is greater; when the marginal sweet spot is smaller, the development benefit is greater and the development difficulty is smaller. Therefore, even if the marginal recoverable sweet spot is not obtained in the same coordinate system, an estimate of the development benefit and development difficulty of the target shale formation can be obtained based on the trajectory trends of the potential benefit curve and the development cost curve.

[0179] In addition, if Figure 2 As shown, the potential profit curve has multiple curves depending on the years. When obtaining the marginal mineable sweet spot, the intersection of the 10-year potential profit curve and the development cost curve is usually taken as the marginal mineable sweet spot, but it is not fixed and can be appropriately adjusted and modified according to the actual situation and requirements of the production data.

[0180] In summary, the embodiments of the present application provide a method for assessing the difficulty of shale formation development, including: collecting geological sweet spot parameters and the open flow rate of initial gas production test of the target shale formation; calculating a geological sweet spot coefficient based on the geological sweet spot parameters and the open flow rate; calculating a predicted initial gas production based on the geological sweet spot coefficient; calculating potential benefits based on the current oil and gas price and discount rate, the predicted initial gas production, and the gas production attenuation rate of the target shale formation; generating a potential benefit curve based on different geological sweet spot coefficients and their corresponding potential benefits; collecting engineering sweet spot parameters and sand carrying ratio of the target shale formation; calculating an engineering sweet spot coefficient based on the engineering sweet spot parameters and the sand carrying ratio; calculating development costs based on the engineering sweet spot coefficient; generating a development cost curve based on different engineering sweet spot coefficients and their corresponding development costs; obtaining a marginal recoverable sweet spot coefficient based on the potential benefit curve and the development cost curve; and determining the difficulty of developing the target shale formation based on the marginal recoverable sweet spot coefficient. The geological sweet spot coefficient reflects the initial gas production and potential benefits, and the engineering sweet spot coefficient reflects the fracturing scale and fracturing cost. This application obtains the marginal mineable sweet spot coefficient through the geological sweet spot coefficient and the engineering sweet spot coefficient, realizes the development benefit and cost evaluation of the shale formation, and at the same time determines whether the shale formation has mining value and the difficulty of development.

[0181] Example 2

[0182] Based on the method for assessing the difficulty of shale formation development disclosed in the first embodiment of the present invention, this embodiment specifically discloses a specific example of applying the method for assessing the difficulty of shale formation development, and the specific content is as follows:

[0183] According to the logging interpretation results of a shale formation, the parameters such as shale content Vs, silica content Vq, carbon content Vc, organic carbon content TOC, kerogen content Vker, porosity Φ, gas saturation Sg, pore pressure Pp and total gas content are selected as geological sweet spot parameters. The initial gas content is calculated by the actual gas production P after fracturing. D By calculating the correlation coefficients between these geological sweet spot parameters and initial gas production, it was found that TOC, Φ, Vker, Pf, and PD had a greater impact on gas production, with correlation coefficients greater than 0.35, while Vs, Vq, and Vc had little impact on gas production, with correlation coefficients less than 0.15, as shown in Table 1.

[0184] Through the analysis of the geological sweet spot parameters of the shale formation, five parameters, namely organic carbon content, kerogen volume, gas porosity, water saturation and pore pressure, were selected as the main influencing parameters of the geological sweet spot of the shale formation, that is, the main geological sweet spot parameters, and their influence on gas production is: Pf>TOC>Φ>Sg>Vker.

[0185]

[0186] Table 1

[0187] After the main geological sweet spot parameters are optimized using the correlation coefficient method, the comprehensive coefficient of each main geological sweet spot parameter is obtained using the multiple correlation coefficient method. The comprehensive coefficient is R i *1 / CR i , and further obtained the weights of the main geological sweet spot parameters of shale formations, as shown in Table 2.

[0188] parameter TOC (%) POR (%) Vker (%) Sg(%) <![CDATA[P f (g / cm 3 )]]> Sorting 2 3 5 4 1 <![CDATA[1 / CR i ]]> 0.703 0.633 0.545 0.317 0.319 Comprehensive coefficient 0.393 0.264 0.194 0.127 0.182 Normalization 0.339 0.228 0.167 0.110 0.157

[0189] Table 2

[0190] Calculate the geological sweet spot coefficient X using the data in Table 1 and Table 2 G and the actual gas production of the shale formation P D Compare, such as Figure 5 The figure shows the relationship between geological sweet spot parameters and gas production. Figure 5 The higher the geological sweet spot of the shale formation, the higher the actual gas production, and the lower the geological sweet spot coefficient, the smaller the actual gas production. There is an exponential relationship between gas production and the geological sweet spot coefficient, and the correlation between them reaches 0.76, which is slightly smaller than the geological sweet spot coefficient calculated using the radar area model. It is also evaluated that the geological sweet spots of these wells are good, and are far better than the evaluation results of a single parameter.

[0191] Based on the well logging interpretation results for this shale formation, the shale content (Vs), silica content (Vq), carbon content (Vc), brittleness index (Brit), fracture pressure (Pp), pore pressure (Pf), and stress difference coefficient (Δσ) were selected as engineering sweet spot parameters. By calculating the correlation coefficients between these engineering sweet spot parameters and the sand-carrying ratio, it was found that Vs, Brit, Vc, and Δσ have a significant impact on the sand-carrying ratio, with correlation coefficients greater than 0.25, while Vq, Pp, and Pf have little impact on the sand-carrying ratio, with correlation coefficients less than 0.25, as shown in Table 3.

[0192]

[0193] Table 3

[0194] Through the analysis of the engineering sweet spot parameters of the shale formation, four parameters, namely mud content, brittleness index, ash content and stress difference coefficient, were selected as the main engineering sweet spot parameters of the shale formation, and the influence of each parameter on the sand carrying ratio was: Brit>Δσ>Vs>Vc.

[0195] After optimizing the main engineering sweet spot parameters using the correlation coefficient method, the comprehensive coefficient of each main engineering sweet spot parameter is obtained using the multiple correlation coefficient method. The comprehensive coefficient is R i *1 / CR i , we further obtained the weights of the main engineering sweet spot parameters of shale formations, as shown in Table 4.

[0196]

[0197]

[0198] Table 4

[0199] Finally, the engineering sweet spot coefficient of the shale formation is calculated, and the relationship between the engineering sweet spot coefficient and the sand carrying ratio is compared, such as Figure 6 shown.

[0200] According to the regression formula y1=550*x1 3.48 Predict the initial gas production, and then according to the formula:

[0201]

[0202] The potential benefits are obtained, where x1 is the geological sweet spot coefficient, y1 is the predicted initial gas production, d1 = -0.15, d2 = 0.09, and the shale formation development cost y2 is determined based on the engineering sweet spot coefficient x2. The calculation equation is y2 = 4000 + 5000 * (0.63 - 3.39 * ln (x2)). 3 , and finally obtain the potential benefit curve and development cost curve, such as Figure 4As shown, the potential benefit curve increases with the geological sweet spot coefficient, while the development cost curve decreases with the engineering sweet spot coefficient. The intersection of the two curves is the marginal mineable sweet spot. The marginal mineable sweet spot coefficient of this shale formation is slightly greater than 0.4, indicating that the development difficulty of this shale formation is moderate to easy, and adopting an appropriate mining plan can achieve good returns.

[0203] Example 3

[0204] Based on the method for evaluating the difficulty of shale formation development disclosed in the above-mentioned embodiment of the present invention, the potential profit curve and development cost curve of the shale formation can be obtained. In Example 3 of the present application, it is also possible to further obtain a payback curve, that is, a development cost recovery curve, based on the obtained geological sweet spot parameters and the potential profit curve, to evaluate the payback time of the shale formation development cost.

[0205] Specifically, under the conditions of known engineering sweet spot coefficient and current development cost, the potential benefit corresponding to the development cost is obtained according to the marginal mineable sweet spot coefficient. Under the premise of fixed potential benefit, according to the formula:

[0206]

[0207] Among them, E0=y*p, y is the predicted initial gas production, p is the oil and gas price, d1 is the gas production attenuation rate, d2 is the discount rate, and n is the mining life.

[0208] And the predicted regression equation y = ax b , and obtain the recovery period curve related to the geological sweet spot coefficient and mining years.

[0209] Where x is the geological sweet spot coefficient, y is the initial gas production, and a and b are regression coefficients determined by the regression algorithm.

[0210] like Figure 7 As shown, this is a curve chart of the years for recovering development costs obtained in another embodiment of the present application. It can be seen that the larger the geological sweet spot coefficient, the shorter the time for recovering development costs; the smaller the geological sweet spot coefficient, the longer the time for recovering development costs. Figure 7 The potential yield curve in the figure also shows that the geological sweet spot is an important factor affecting the difficulty of shale formation development.

[0211] Specifically, Figure 7 When the geological sweet spot parameter is 0.4, the cost recovery period is 3 years, which means that investment returns will be obtained 3 years after shale formation mining. At the same time, the geological sweet spot parameter value of 0.4 indicates that the formation development is relatively easy.

[0212] Example 4

[0213] Based on the method for evaluating the difficulty of shale formation development disclosed in the above embodiment of the present invention, Figure 8 Specifically disclosed is a device for assessing the difficulty of shale formation development using the method for assessing the difficulty of shale formation development.

[0214] like Figure 8 As shown, an embodiment of the present invention discloses a device for evaluating the difficulty of shale formation development, the device comprising:

[0215] The first acquisition unit 801 is used to collect geological sweet spot parameters of the target shale formation and the open flow rate of the initial gas production test;

[0216] A first calculation unit 802 is configured to calculate a geological sweet spot coefficient according to the geological sweet spot parameters and the open flow rate;

[0217] The second calculation unit 803 is configured to calculate a predicted initial gas production according to the geological sweet spot coefficient; and calculate potential benefits according to the current oil and gas price and discount rate, the predicted initial gas production, and the gas production attenuation rate of the target shale formation;

[0218] The first generating unit 804 is configured to generate a potential benefit curve according to different geological sweet spot coefficients and their corresponding potential benefits;

[0219] The second acquisition unit 805 is used to acquire the engineering sweet spot parameters and sand carrying ratio of the target shale formation;

[0220] The third calculation unit 806 is used to calculate the engineering sweet spot coefficient according to the engineering sweet spot parameter and the sand carrying ratio;

[0221] A fourth calculation unit 807 is configured to calculate a development cost based on the engineering sweet spot coefficient and the sand carrying ratio;

[0222] The second generating unit 808 is configured to generate a development cost curve according to different engineering sweet spot coefficients and their corresponding development costs;

[0223] An acquisition unit 809 is configured to obtain a marginal sweet spot coefficient according to the potential benefit curve and the development cost curve;

[0224] The judgment unit 810 is configured to judge the development difficulty of the target shale formation according to the marginal recoverable sweet spot coefficient.

[0225] The specific working processes of the first acquisition unit 801, the first calculation unit 802, the second calculation unit 803, the first generation unit 804, the second acquisition unit 805, the third calculation unit 806, the fourth calculation unit 807, the second generation unit 808, the acquisition unit 809 and the judgment unit 810 in the device for assessing the difficulty of shale formation development disclosed in the above embodiment of the present invention can be referred to the corresponding contents in the method for assessing the difficulty of shale formation development disclosed in the above embodiment 1 of the present invention, and will not be repeated here.

[0226] In summary, the present invention provides a device for assessing the difficulty of shale formation development, comprising: collecting geological sweet spot parameters and the open flow rate of initial gas production test of the target shale formation; calculating a geological sweet spot coefficient based on the geological sweet spot parameters and the open flow rate; calculating a predicted initial gas production rate based on the geological sweet spot coefficient; calculating potential benefits based on the current oil and gas price and discount rate, the predicted initial gas production rate, and the gas production attenuation rate of the target shale formation; generating a potential benefit curve based on different geological sweet spot coefficients and their corresponding potential benefits; collecting engineering sweet spot parameters and sand carrying ratio of the target shale formation; calculating an engineering sweet spot coefficient based on the engineering sweet spot parameters and the sand carrying ratio; calculating development costs based on the engineering sweet spot coefficient; generating a development cost curve based on different engineering sweet spot coefficients and their corresponding development costs; obtaining a marginal recoverable sweet spot coefficient based on the potential benefit curve and the development cost curve; and determining the difficulty of developing the target shale formation based on the marginal recoverable sweet spot coefficient. The geological sweet spot coefficient reflects the initial gas production rate and potential benefits, while the engineering sweet spot coefficient reflects the scale and cost of fracturing. This application obtains the marginal mineable sweet spot coefficient through the geological sweet spot coefficient and the engineering sweet spot coefficient, realizes the development benefit and cost evaluation of the shale formation, and at the same time determines whether the shale formation has mining value and the difficulty of development.

[0227] Example 5

[0228] This embodiment also provides a computer-readable storage medium, such as a flash memory, a hard disk, a multimedia card, a card-type memory (for example, an SD or DX memory, etc.), a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a programmable read-only memory (PROM), a magnetic memory, a disk, an optical disk, a server, an App application store, etc., on which a computer program is stored. When the computer program is executed by a processor, the method steps of the first embodiment can be implemented, and this embodiment will not be repeated here.

[0229] Example 6

[0230] Figure 9A connection block diagram of an electronic device 900 provided in an embodiment of the present application is shown in FIG. Figure 9 As shown, the electronic device 900 may include: a processor 901 , a memory 902 , a multimedia component 903 , an input / output (I / O) interface 904 , and a communication component 905 .

[0231] The processor 901 is configured to execute all or part of the steps in the method for assessing shale formation development difficulty as described in Example 1. The memory 902 is configured to store various types of data, such as instructions for any application or method in the electronic device, as well as data related to the application.

[0232] The processor 901 can be implemented by an application specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field programmable gate array (FPGA), a controller, a microcontroller, a microprocessor, or other electronic components, and is used to execute the method for assessing the difficulty of shale formation development in the above-mentioned embodiment 1.

[0233] The memory 902 can be implemented by any type of volatile or non-volatile memory device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk.

[0234] The multimedia component 903 may include a screen and an audio component. The screen may be a touch screen, and the audio component is used to output and / or input audio signals. For example, the audio component may include a microphone for receiving external audio signals. The received audio signals may be further stored in a memory or sent via a communication component. The audio component also includes at least one speaker for outputting audio signals.

[0235] The I / O interface 904 provides an interface between the processor 901 and other interface modules, which may be a keyboard, a mouse, buttons, etc. These buttons may be virtual buttons or physical buttons.

[0236] The communication component 905 is used for wired or wireless communication between the electronic device 900 and other devices. Wireless communication, such as Wi-Fi, Bluetooth, Near Field Communication (NFC), 2G, 3G or 4G, or one or a combination thereof, can include a Wi-Fi module, a Bluetooth module, or an NFC module.

[0237] In summary, the present application provides a method, device, storage medium, and electronic device for assessing the difficulty of shale formation development. The method includes: collecting geological sweet spot parameters and the open flow rate of initial gas production test of the target shale formation; calculating a geological sweet spot coefficient based on the geological sweet spot parameters and the open flow rate; calculating a predicted initial gas production rate based on the geological sweet spot coefficient; calculating potential benefits based on the current oil and gas price and discount rate, the predicted initial gas production rate, and the gas production decay rate of the target shale formation; generating a potential benefit curve based on different geological sweet spot coefficients and their corresponding potential benefits; collecting engineering sweet spot parameters and sand carrying ratio of the target shale formation; calculating an engineering sweet spot coefficient based on the engineering sweet spot parameters and the sand carrying ratio; calculating development costs based on the engineering sweet spot coefficient; generating a development cost curve based on different engineering sweet spot coefficients and their corresponding development costs; obtaining a marginal recoverable sweet spot coefficient based on the potential benefit curve and the development cost curve; and determining the difficulty of developing the target shale formation based on the marginal recoverable sweet spot coefficient. The geological sweet spot coefficient reflects the initial gas production rate and potential benefits, while the engineering sweet spot coefficient reflects the fracturing scale and fracturing cost. This application obtains the marginal mineable sweet spot coefficient through the geological sweet spot coefficient and the engineering sweet spot coefficient, realizes the development benefit and cost evaluation of the shale formation, and at the same time determines whether the shale formation has mining value and the difficulty of development.

[0238] In the several embodiments provided in the present application, it should be understood that the disclosed method can also be implemented in other ways. The method embodiments described above are merely illustrative.

[0239] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0240] Although the embodiments disclosed in this application are as described above, the above contents are merely embodiments adopted to facilitate understanding of this application and are not intended to limit this application. Any person skilled in the art of the present application may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in this application. However, the scope of patent protection of this application shall still be based on the scope defined by the attached claims.

Claims

1. A method for evaluating the difficulty of shale formation development, characterized in that: The method comprises: Collect geological sweet spot parameters of target shale formation and open flow rate of initial gas production test; Calculating a geological sweet spot coefficient according to the geological sweet spot parameters and the open flow rate; Calculate and predict the initial gas production based on the geological sweet spot coefficient; calculating potential benefits based on current oil and gas prices and discount rates, the predicted initial gas production, and the gas production decline rate of the target shale formation; Generate a potential benefit curve based on different geological sweet spot coefficients and their corresponding potential benefits; Collect engineering sweet spot parameters and sand carrying ratio of target shale formation; Calculating an engineering sweet spot coefficient according to the engineering sweet spot parameters and the sand carrying ratio; Calculating the development cost based on the engineering sweet spot coefficient; Generate a development cost curve based on different engineering sweet spot coefficients and their corresponding development costs; Obtaining a marginal sweet spot coefficient according to the potential benefit curve and the development cost curve; Determining the difficulty of developing the target shale formation according to the marginal recoverable sweet spot coefficient; The method of calculating the geological sweet spot coefficient according to the geological sweet spot parameter and the open flow rate includes: calculating the correlation coefficient between the geological sweet spot parameter and the open flow rate according to the geological sweet spot parameter and the open flow rate; selecting the geological sweet spot parameter corresponding to the correlation coefficient greater than a first preset threshold as the main geological sweet spot parameter; calculating the complex correlation coefficient between each main geological sweet spot parameter and other geological sweet spot parameters; dividing the correlation coefficient of each main geological sweet spot parameter by the respective complex correlation coefficient, and normalizing the obtained results to obtain the weight of each main geological sweet spot parameter; and calculating the weight of each main geological sweet spot parameter according to the formula X. G =∑W ’ i X i Calculate the geological sweet spot coefficient of the target shale formation; where X G is the geological sweet spot coefficient, W ’ i is the weight, X i is the parameter of the i-th main geological sweet spot; The method of calculating the engineering sweet spot coefficient according to the engineering sweet spot parameter and the sand carrying ratio includes: calculating the correlation coefficient between the engineering sweet spot parameter and the sand carrying ratio according to the engineering sweet spot parameter and the sand carrying ratio; selecting the engineering sweet spot parameter corresponding to the correlation coefficient greater than a second preset threshold as the main engineering sweet spot parameter; calculating the complex correlation coefficient between each main engineering sweet spot parameter and other engineering sweet spot parameters; dividing the correlation coefficient of each main engineering sweet spot parameter by the respective complex correlation coefficient, and normalizing the obtained results to obtain the weight of each main engineering sweet spot parameter; and calculating the weight of each main engineering sweet spot parameter according to the formula X. E =∑W ’ i X i Calculate the engineering sweet spot coefficient of the target shale formation; where X E is the engineering sweet spot coefficient, W ’ i is the weight, X i is the i-th main engineering sweet spot parameter; The method of obtaining the marginal sweet spot coefficient based on the potential benefit curve and the development cost curve includes: placing the potential benefit curve and the development cost curve in the same coordinate system; and taking the intersection of the potential benefit curve and the development cost curve of a preset number of years as the marginal sweet spot coefficient.

2. The method according to claim 1, characterized in that The calculating and predicting the initial gas production according to the geological sweet spot coefficient includes: The initial gas production prediction regression equation is constructed based on the historical geological sweet spot coefficient and its corresponding historical initial gas production; The predicted initial gas production is calculated based on the initial gas production prediction regression equation and the geological sweet spot coefficient.

3. The method according to claim 1, characterized in that Calculate potential benefits based on current oil and gas prices and discount rates, the projected initial gas production, and the gas production decline rate of the target shale formation, including: According to the predicted initial gas production, the current oil and gas price and discount rate, and the gas production attenuation rate of the target shale formation, the formula: Calculate the total future cash benefit value E, i.e. the potential benefit; Where E0=y*p, y is the predicted initial gas production, p is the oil and gas price, d1 is the gas production attenuation rate, d2 is the discount rate, and n is the mining life.

4. The method according to claim 1, wherein The calculation of the development cost according to the engineering sweet spot coefficient includes: Calculating the fracturing production cost according to the engineering sweet spot coefficient; The development cost is obtained by adding the fracturing production cost and the drilling and completion cost of the target shale formation.

5. The method according to claim 1, wherein The sand carrying ratio of the target shale formation is collected, including: Collect the total sand addition and fluid injection volumes during the fracturing process of the target shale formation; The sand carrying ratio is calculated based on the sand addition amount and the liquid injection amount.

6. A device for evaluating the difficulty of shale formation development, characterized in that: The device comprises: The first acquisition unit is used to collect the geological sweet spot parameters of the target shale formation and the open flow rate of the initial gas production test; A first calculation unit is used to calculate a geological sweet spot coefficient according to the geological sweet spot parameter and the open flow rate; a second calculation unit, configured to calculate a predicted initial gas production according to the geological sweet spot coefficient; and calculate potential benefits according to current oil and gas prices and discount rates, the predicted initial gas production, and the gas production attenuation rate of the target shale formation; The first generating unit is used to generate a potential benefit curve according to different geological sweet spot coefficients and their corresponding potential benefits; The second acquisition unit is used to collect the engineering sweet spot parameters and sand carrying ratio of the target shale formation; A third calculation unit is used to calculate the engineering sweet spot coefficient according to the engineering sweet spot parameter and the sand carrying ratio; a fourth calculation unit, configured to calculate a development cost according to the engineering sweet spot coefficient and the sand carrying ratio; The second generating unit is used to generate a development cost curve according to different engineering sweet spot coefficients and their corresponding development costs; an acquisition unit, configured to obtain a marginal sweet spot coefficient according to the potential benefit curve and the development cost curve; a judgment unit, configured to judge the difficulty of developing the target shale formation according to the marginal recoverable sweet spot coefficient; The first calculation unit is used to calculate the correlation coefficient between the geological sweet spot parameter and the open flow rate according to the geological sweet spot parameter and the open flow rate; select the geological sweet spot parameter corresponding to the correlation coefficient greater than the first preset threshold as the main geological sweet spot parameter; calculate the complex correlation coefficient between each main geological sweet spot parameter and other geological sweet spot parameters; divide the correlation coefficient of each main geological sweet spot parameter by its own complex correlation coefficient, and normalize the obtained results to obtain the weight of each main geological sweet spot parameter; according to the formula X G =∑W ’ i X i Calculate the geological sweet spot coefficient of the target shale formation; where X G is the geological sweet spot coefficient, W ’ i is the weight, X i is the parameter of the i-th main geological sweet spot; The third calculation unit is used to calculate the correlation coefficient between the engineering sweet spot parameter and the sand carrying ratio according to the engineering sweet spot parameter and the sand carrying ratio; select the engineering sweet spot parameter corresponding to the correlation coefficient greater than the second preset threshold as the main engineering sweet spot parameter; calculate the complex correlation coefficient between each main engineering sweet spot parameter and other engineering sweet spot parameters; divide the correlation coefficient of each main engineering sweet spot parameter by its own complex correlation coefficient, and normalize the obtained results to obtain the weight of each main engineering sweet spot parameter; according to the formula X E =∑W ’ i X i Calculate the engineering sweet spot coefficient of the target shale formation; where X E is the engineering sweet spot coefficient, W ’ i is the weight, X i is the i-th main engineering sweet spot parameter; The acquisition unit is used to place the potential benefit curve and the development cost curve in the same coordinate system; and take the intersection of the potential benefit curve and the development cost curve of a preset number of years as the marginal exploitable sweet spot coefficient.

7. A storage medium, characterized in that: The computer program stored in the storage medium can be executed by one or more processors and can be used to implement the method for assessing the difficulty of shale formation development as described in any one of claims 1 to 5.

8. An electronic device, characterized in that: The method comprises a memory and a processor, wherein a computer program is stored in the memory, and the memory and the processor are communicatively connected to each other. When the computer program is executed by the processor, the method for assessing the difficulty of shale formation development as described in any one of claims 1 to 5 is executed.

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