Method for calculating size and dosage of shale gas fracturing temporary plugging balls

Abstract

The invention belongs to the technical field of fracturing temporary plugging balls, and particularly relates to a shale gas fracturing temporary plugging ball size and use amount calculation method, which comprises the following steps: A1, acquiring geological information of a shale gas reservoir, and calculating the number n of fractures and the fracture design length L1. I (i = 1, 2,..., n) according to the geological information of the shale gas reservoir; a2, a target layer section is packed through a packer, perforation is conducted according to the preset fracture orientation and the number of fractures in the designed layer section, and the initial area S1. I (i = 1, 2,..., n) of a shot hole is calculated; a3, high-pressure fracturing liquid is pumped into the target layer section, the corresponding shot hole area S2. I (i = 1, 2,..., n) and the shot hole diameter d2. I (i = 1, 2,..., n) are obtained, and the shot hole area increment Si is calculated; and carrying out temporary plugging fracturing according to the calculation result until the extension condition of each fracture meets the design target, thereby improving the non-uniform extension condition of the shale gas hydraulic fracturing fracture and realizing accurate and efficient transformation of the shale gas reservoir.

Description

Technical Field

[0001] The invention belongs to the technical field of calculation of temporary plugging balls for fracturing, and in particular to a method for calculating the size and amount of temporary plugging balls for fracturing of shale gas. Background Art

[0002] my country has abundant reserves of unconventional oil and gas resources. Unconventional oil and gas resources represented by shale gas have good exploration value and development potential, and have become a hot spot for exploration and development in recent years. Compared with conventional oil and gas reservoirs, shale reservoirs generally have the characteristics of low porosity, low permeability, and ultra-low porosity and ultra-low permeability. Large-scale hydraulic fracturing has achieved significant results in increasing oil and gas production. Due to the unique geological conditions of shale gas, the development of internal stratification, the heterogeneity of mineral distribution, and the initial cracks at the wellhead, the mechanical properties of shale gas reservoirs in different directions are significantly different. During the fracturing process, the extension of cracks in different layers and different directions of the same layer of shale gas reservoirs shows significant differences. The degree of unstable expansion of cracks is high, which significantly increases the complexity and prediction difficulty of the hydraulic fracturing crack expansion process. How to promote the uniform expansion of the fracture network and increase the swept volume of the fracture network has become a focal issue affecting the effect of hydraulic fracturing.

[0003] At present, in order to solve the problem of uneven expansion of hydraulic fracturing cracks in shale gas reservoirs, the method of temporary plugging fracturing is generally used to inhibit the continued extension of dominant expansion cracks and promote the extension of underdeveloped fractures, ultimately making the cracks in the same fracturing layer expand evenly, increasing the effective fracturing transformation volume and fracture control volume, thereby achieving the purpose of increasing production and efficiency.

[0004] However, the traditional method is to place a corresponding number of temporary plugging balls or temporary plugging agents according to the number of blastholes that need to be plugged or the volume of fractures that need to be plugged. This can improve the extension of underdeveloped fractures to a certain extent and promote the further extension of these fractures. However, the number and size of temporary plugging balls used are mostly determined based on experience. The development plan formulated in this way is characterized by generality and inaccuracy. How to accurately judge the number of temporarily plugged fractures, determine the number and size of temporary plugging balls, and realize real-time, efficient and accurate regulation of hydraulic fracturing networks is still a major technical problem in the field of oil and gas field development.

[0005] To this end, the present invention provides a method for calculating the size and amount of temporary plugging balls for shale gas fracturing. Summary of the invention

[0006] In order to make up for the deficiencies of the prior art, at least one technical problem raised in the background technology is solved.

[0007] The technical solution adopted by the present invention to solve the technical problem is: a method for calculating the size and amount of temporary plugging balls for shale gas fracturing according to the present invention comprises the following steps:

[0008] A1. Obtain geological information of shale gas reservoirs, and calculate the number of fractures n and the fracture design length L based on the geological information of shale gas reservoirs. 1.i (i=1, 2, ..., n);

[0009] A2. Use the packer to isolate the target layer, perform perforation according to the preset fracture orientation and number of fractures in the designed layer, and calculate the initial area S of the blasthole. 1.i (i=1, 2, ..., n);

[0010] A3. Pump high-pressure fracturing fluid into the target layer to obtain the corresponding blasthole area S 2.i (i = 1, 2, ..., n) and the borehole diameter d 2.i (i=1, 2, ..., n), and calculate the blasthole area increment △S i ;

[0011] A4. Calculate the extension length L of each crack 2.i (i=1, 2, …, n), determine the curve expression corresponding to the coefficient of variation of different crack extension lengths;

[0012] A5. Calculate the temporary blocking ball pitching size d based on the coefficient of variation 1 and the number of temporarily blocked balls a 1 , and then adjust d according to actual needs 1 and a 1 The numerical value of .

[0013] Preferably, the initial area S of the blasthole is 1.i The calculation method is:

[0014] B1. Divide the blasthole into x (x = 1, 2, ..., x) segments at equal intervals, and measure the starting radius d of each segment respectively. x起 and the end point radius d x终 ;

[0015] B2. Calculate the average area of ​​each section in the target borehole And according to the average area Calculate the initial area S of the blasthole 1.i ;

[0016] in,

[0017]

[0018] Preferably, the corresponding hole area increment ΔS after perforation i The calculation method is:

[0019] △S i =S 2.i -S 1.i .

[0020] Preferably, the crack extension length L 2.i The calculation method is:

[0021]

[0022] Preferably, the calculation method of the curve expression corresponding to the coefficient of variation of different crack extension lengths is:

[0023] The coefficient of variation of crack extension length is determined based on the Lorentz curve and the single blasthole area increment;

[0024] Among them, the Gini coefficient is:

[0025]

[0026] Preferably, the calculation method for determining the coefficient of variation of crack extension length by a single blasthole area increment is:

[0027] Through △S i Calculate the ratio of the area increment of the blasthole to the sum of the area increments of all blastholes:

[0028] △S i / ∑ n △S i ;

[0029] Arrange the ratios in ascending order, so that n groups can be obtained, which are:

[0030]

[0031] Calculate (X i , Y i ), the Lorentz curve for evaluating the heterogeneity of the extension length of a single crack is obtained, and the equation is:

[0032]

[0033] Then the coefficient of variation is:

[0034]

[0035] Preferably, the temporary blocking ball pitching size d 1 and the number of temporarily blocked balls a 1 The calculation of includes the following steps:

[0036] C1. According to the design length L of each cluster of cracks 1.i Calculate the coefficient of variation of crack length with reference to the standard V' k ;

[0037] C2. Determine the heterogeneous elastic interval ψ of crack extension based on actual engineering conditions and eliminate data;

[0038] C3. Perform temporary plugging and fracturing to further transform underdeveloped fractures and determine the size of the temporary plugging ball d 1 and the number of temporarily blocked balls a 1 Numeric value.

[0039] Preferably, the crack length variation coefficient is referenced to the standard V' k The equation is:

[0040]

[0041] Preferably, in step C3, the ball blocking pitching size d 1 The range and number of temporarily blocked balls a 1 The numerical calculation method is:

[0042] When (V' k +ψ)≤V k ≤1;

[0043] The temporary blocking ball pitch size d 1 Not less than the maximum blasthole size during temporary plugging:

[0044] d 1 ≥max(d 1.1 d 1.2 …d 1.n );

[0045] Temporary blocking ball number a 1 for:

[0046] a 1 =(V k -V' k +ψ)n.

[0047] Preferably, the ball blocking pitching size d 1 The calculation method is:

[0048] According to the variation coefficient of the blasthole area increment and the variation coefficient of the crack length, refer to the standard V' k The number of temporary plugging balls calculated from the number of perforations in the target layer is rounded up to:

[0049] b 1 =rouundup(a 1 , 0).

[0050] The beneficial effects of the present invention are as follows:

[0051] 1. The present invention conducts real-time video monitoring of the perforated holes during fracturing, and utilizes the characteristics of large liquid absorption of the dominant expansion cracks, strong hole abrasion, and large liquid flow rate at the seam mouth. After the ball is dropped, the temporary plugging ball will intelligently select the dominant expansion cracks for plugging, and the size of the temporary plugging ball is determined and the number of temporary plugging balls is calculated according to the real-time state of hole abrasion, so that the optimal plugging can be formed after each ball drop, and the underdeveloped cracks are fully expanded to avoid the formation of underdeveloped cracks after the dominant cracks are blocked;

[0052] 2. The fracture extension evaluation method based on the Lorentz curve of the present invention can quantitatively characterize the heterogeneity of fracture length extension according to the blasthole area increment, evaluate the fracturing effect by the blasthole abrasion variation coefficient, and intelligently plug the dominant extension fractures in combination with the graded ball throwing technology. This technology is then used for post-adjustment evaluation, and a strong basis is provided for the evaluation of hydraulic fracturing measures by comparing the blasthole abrasion Gini coefficients at different stages. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The present invention will be further described below in conjunction with the accompanying drawings.

[0054] Figure 1 is the Lorentz curve of the hole area increment of each crack corresponding to the blasthole monitored before temporary plugging in the present invention;

[0055] Figure 2 is the Lorentz curve of the hole area increment of each crack corresponding to the blasthole monitored after temporary plugging in the present invention;

[0056] Figure 3 is the hole area of ​​each crack corresponding to the blasthole monitored after perforation in the present invention;

[0057] Figure 4 is the hole area of ​​each crack corresponding to the blasthole monitored before temporary plugging in the present invention;

[0058] Figure 5 is the hole area increment of each crack corresponding to the blasthole monitored before temporary plugging in the present invention;

[0059] Figure 6 is the hole diameter of the blasthole corresponding to each crack monitored before temporary plugging in the present invention;

[0060] Figure 7 is the hole area of ​​each crack corresponding to the blasthole monitored after temporary plugging in the present invention;

[0061] Figure 8 is the hole area increment of each crack corresponding to the blasthole monitored after temporary plugging in the present invention;

[0062] Fig. 9 is a flow chart of the calculation method of the present invention;

[0063] Fig.10is a flow chart of a method for calculating the initial area of ​​a blasthole in the present invention;

[0064] Fig.11 It is a flow chart of a method for calculating the number of temporary blocking balls and temporary blocking balls in the present invention. DETAILED DESCRIPTION

[0065] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0066] like Figures 9 to 11 As shown, a method for calculating the size and amount of temporary plugging balls for shale gas fracturing according to the present invention comprises the following steps:

[0067] A1. Obtain geological information of shale gas reservoirs, and calculate the number of fractures n and the fracture design length L based on the geological information of shale gas reservoirs. 1.i (i=1, 2, ..., n);

[0068] Obtain shale gas reservoir geological information, obtain reservoir stress profile distribution by designing reservoir Young's modulus, Poisson's ratio, well logging interpretation, and geostress magnitude and direction of the fracturing section, and clarify the number of fractures n and fracture design length L in the target layer according to geostress interpretation and well logging interpretation. 1.i , to meet the strength requirements of reservoir fracturing transformation.

[0069] A2. Use the packer to isolate the target layer, perform perforation according to the preset fracture orientation and number of fractures in the designed layer, and calculate the initial area S of the blasthole. 1.i (i=1, 2, ..., n);

[0070] A packer is placed at the toe of the designed fracturing section to physically isolate the target layer. Perforation is performed according to the preset fracture orientation and number of fractures in the designed layer. The initial area S of the blasthole is recorded using a blasthole video monitoring system. 1.i .

[0071] The initial area of ​​the blasthole is S 1.i The calculation method is:

[0072] B1. Divide the blasthole into x (x = 1, 2, ..., x) segments at equal intervals, and measure the starting radius d of each segment respectively. x起 and the end point radius d x终 ;

[0073] B2. Calculate the average area of ​​each section in the target borehole And according to the average area Calculate the initial area S of the blasthole 1.i ;

[0074] in,

[0075]

[0076] Since the inner wall of the hole is not uniform, the accuracy of the value can be effectively improved by calculating the average value.

[0077] A3. Pump high-pressure fracturing fluid into the target layer to obtain the corresponding blasthole area S 2.i (i = 1, 2, ..., n) and the borehole diameter d 2.i (i=1, 2, ..., n), and calculate the blasthole area increment △S i ;

[0078] After perforating, the surface fracturing vehicle pumps high-pressure fracturing fluid into the target layer, initiates fracturing at the corresponding perforation position in the target layer, opens multiple fractures, and monitors the area S of each fracture corresponding to the blasthole. 2.i and the blasthole diameter d 2.i , calculate the blasthole area increment △S i ;

[0079] △S i =S 2.i -S 1.i ;

[0080] A4. Calculate the extension length L of each crack 2.i (i=1, 2, …, n), determine the curve expression corresponding to the coefficient of variation of different crack extension lengths;

[0081] A5. Calculate the temporary blocking ball pitching size d based on the coefficient of variation 1 and the number of temporarily blocked balls a 1 , and then adjust d according to actual needs 1 and a 1 The numerical value of .

[0082] In general, the fracture absorption profile is positively correlated with the blasthole area increment, and the fracture absorption profile is positively correlated with the fracture extension length. The calculated blasthole area increment can be used to determine the extension length L of each fracture. 2.i ;

[0083]

[0084] Based on the method of determining the variation coefficient of crack extension length by using the Lorentz curve and a single blasthole area increment, the curve expressions corresponding to different variation coefficients of crack extension length are determined.

[0085] The Lund curve was proposed by American statistician Lorenz. It was originally used to study the distribution of national income among citizens. If the distribution is uniform, the curve is a straight line with a slope of 45° ( Figure 1), called the "perfectly uniform line", when the distribution of all national income is concentrated at one point, the curve is a broken line ( Figure 1 ), called the "completely inhomogeneous line", the Lorenz curve in general is between these two cases, in the form of a "convex" curve ( Figure 1 ), therefore, the Gini coefficient can be defined as:

[0086]

[0087] The Lorenz curve is used to evaluate the heterogeneity of reservoir fracture expansion, and the coefficient of variation (Gini coefficient) is used to evaluate the degree of uneven fracture expansion.

[0088] The specific method is: using the blasthole area monitored in real time by the blasthole video monitoring system to calculate the area increment △S corresponding to the blasthole of the crack i , and calculate the ratio of the area increment of the blasthole to the total area increment of all blastholes (△S i / ∑ n △S i ), and arrange them in ascending order, so that n groups can be obtained And calculate (X i , Y i ) and then obtain the Lorentz curve ( Figure 2 ):

[0089]

[0090] Then the coefficient of variation is:

[0091]

[0092] The calculated value of the coefficient of variation is between 0 and 1. Generally speaking, V k The closer the calculated value of V' is to 1, the stronger the heterogeneity of hydraulic fracturing crack extension in the target layer is, and the greater the difference in crack length is. k The closer the calculated value of is to 0, the more uniform the hydraulic fracturing crack expansion in the target layer, the smaller the difference in crack length, and the better the reservoir reconstruction effect. 1.i Calculate the coefficient of variation of crack length with reference to the standard V' k .

[0093]

[0094] According to the basic geological conditions of the target area, combined with the actual engineering conditions, the fracture extension heterogeneity elastic interval ψ is defined. k <V k ≤(V' k+ψ), the hydraulic fracturing fractures extend relatively evenly, which meets the requirements of reservoir fracturing transformation. k +ψ)≤V k When ≤1, the extension heterogeneity of hydraulic fracturing fractures is strong, which does not meet the requirements of reservoir transformation design. Temporary plugging and fracturing are needed to promote the further extension of underdeveloped fractures to meet the design objectives of reservoir transformation.

[0095] Temporary blocking ball pitching size d 1 and the number of temporarily blocked balls a 1 The calculation of includes the following steps:

[0096] C1. According to the design length L of each cluster of cracks 1.i Calculate the coefficient of variation of crack length with reference to the standard V' k ;

[0097] C2. Determine the heterogeneous elastic interval ψ of crack extension based on actual engineering conditions and eliminate data;

[0098] C3. Perform temporary plugging and fracturing to further transform underdeveloped fractures and determine the size of the temporary plugging ball d 1 and the number of temporarily blocked balls a 1 Numeric value.

[0099] If the coefficient of variation does not meet the design objectives of reservoir reconstruction, that is, when (V' k +ψ)≤V k ≤1, temporary plugging and fracturing are carried out to further transform the underdeveloped fractures. The size of the temporary plugging ball is d 1 Slightly larger than the maximum blasthole size during temporary plugging:

[0100] d 1 ≥max(d 1.1 d 1.2 …d 1.n ).

[0101] Temporary blocking ball number a 1 for:

[0102] a 1 =(V k -V' k +ψ)n.

[0103] According to the variation coefficient of the blasthole area increment and the variation coefficient of the crack length, refer to the standard V' k The calculated value of temporary plugging balls a is calculated by the number of perforations in the target layer. 1 It may be a decimal. In actual engineering, the number of temporary blocking balls cannot be a decimal. Therefore, the calculated value of the number of temporary blocking balls is rounded up to obtain the number of temporary blocking balls in actual engineering applications, which is:

[0104] b1 =rouundup(a 1 , 0).

[0105] By conducting video monitoring of the perforations during the fracturing process, the blasthole area increment and the coefficient of variation of the blasthole area increment are calculated, and the size and number of temporary plugging balls during temporary fracturing are accurately calculated, the dominant fractures are efficiently and accurately blocked, achieving efficient regulation of the fracturing fracture network and quantitative characterization of the extension status of the fracturing fractures.

[0106] The experimental area of ​​this embodiment adopts the efficient control and evaluation method of the hydraulic fracture network provided by this patent to transform the reservoir. The reservoir in the experimental area is black and gray-black shale, the depth of the hydraulic fracture section is 4988-4927m, and the effective hydraulic fracture thickness is 61m. Combined with the results of well logging, mud logging interpretation, and small layer division, the reservoirs with similar physical properties and small stress differences are divided into one section, and the section length is appropriately reduced for the reservoirs with poor physical properties, and the stress interference is increased. A total of 20 hydraulic fracture sections are designed, with a total of 20 holes in a single section, and a designed construction displacement of 15m 3 / min, taking the 10th stage fracturing operation as an example, the design length of each crack is 150m, and the heterogeneous elastic interval ψ of crack expansion is 0.3, then:

[0107] d 1.1 =d 1.2 =…=d 1.n =150.

[0108] The hole area of ​​each crack monitored after perforation is as follows: Figure 3 As shown in the figure, before the first temporary plugging and fracturing operation, the hole area and hole area increment of each crack monitored corresponding to the blasthole are as follows: Figure 4 and Figure 5 shown.

[0109] like Figure 6 As shown in the figure, before temporary plugging, the uneven Gini coefficient of the blasthole area increment corresponding to a single fracture is 0.5739. The Gini coefficient is relatively large, belonging to the range of 0.3 to 1. The uneven expansion of the fracture is relatively large, and temporary plugging balls need to be put into the machine for temporary plugging and diverting fracturing to improve the uneven expansion of the fracture.

[0110] The size of the temporary plugging ball should be slightly larger than the maximum blasthole diameter of 18.97mm. Combined with the size of the existing temporary plugging balls, a 25mm temporary plugging ball is selected for temporary plugging.

[0111] The number of temporarily blocked balls is:

[0112] a=(0.5738-(0+0.3)*20)=5.4, the number of temporarily blocked balls is rounded up to 6.

[0113] After temporary plugging and fracturing construction, the hole area and hole area increment of each monitored crack corresponding to the blasthole are shown in Table 7 and Table 8 respectively.

[0114] After temporary plugging, the blasthole area corresponding to the dominant expansion fractures changed little, and the underdeveloped fractures were well extended after temporary plugging. The uneven Gini coefficient of the blasthole area increment corresponding to a single fracture was 0.1578, and the Gini coefficient was small, belonging to the range of 0 to 0.3. The Gini coefficient was significantly reduced, and the degree of uneven expansion of each fracture was greatly reduced. The probability of successfully fracturing a complex volume fracture network that meets the design expectations in the target layer is higher, laying a good foundation for increasing production and efficiency of shale gas reservoirs.

[0115] The above-mentioned front, back, left, right, top and bottom are all based on the figures in the specification. Figure 1 As a benchmark, according to the person's observation perspective, the side of the device facing the observer is defined as the front, the left side of the observer is defined as the left, and so on.

[0116] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present invention.

[0117] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for calculating the size and dosage of temporary plugging balls for shale gas fracturing, characterized in that: The following steps are involved: A1. Obtain geological information of shale gas reservoirs, and calculate the number of fractures n and the fracture design length L based on the geological information of shale gas reservoirs. 1.i (i=1, 2, ..., n); A2. Use the packer to isolate the target layer, perform perforation according to the preset fracture orientation and number of fractures in the designed layer, and calculate the initial area S of the blasthole. 1.i (i=1, 2, ..., n); A3. Pump high-pressure fracturing fluid into the target layer to obtain the corresponding blasthole area S 2.i (i = 1, 2, ..., n) and the borehole diameter d 2.i (i=1, 2, ..., n), and calculate the blasthole area increment △S i ; A4. Calculate the extension length L of each crack 2.i (i=1, 2, …, n), determine the curve expression corresponding to the coefficient of variation of different crack extension lengths; A5. Calculate the temporary blocking ball size d1 and the temporary blocking ball quantity a1 according to the coefficient of variation, and then adjust the values ​​of d1 and a1 according to actual needs.

2. The method for calculating the size and amount of temporary plugging balls for shale gas fracturing according to claim 1, characterized in that: Initial area of ​​blasthole S 1.i The calculation method is: B1. Divide the blasthole into x (x = 1, 2, ..., x) segments at equal intervals, and measure the starting radius d of each segment respectively. x起 and the end point radius d x终 ; B2. Calculate the average area of ​​each section in the target borehole And according to the average area Calculate the initial area S of the blasthole 1.i ; in, 3. The method for calculating the size and amount of temporary plugging balls for shale gas fracturing according to claim 2, characterized in that: The corresponding hole area increment after perforation △S i The calculation method is: △S i =S 2.i -S 1.i 。 4. The method for calculating the size and amount of temporary plugging balls for shale gas fracturing according to claim 3, characterized in that: Crack extension length L 2.i The calculation method is:

5. The method for calculating the size and amount of temporary plugging balls for shale gas fracturing according to claim 4, characterized in that: The calculation method of the curve expression corresponding to the coefficient of variation of different crack extension lengths is: The coefficient of variation of crack extension length is determined based on the Lorentz curve and the single blasthole area increment; Among them, the Gini coefficient is:

6. A method for calculating the size and amount of temporary plugging balls for shale gas fracturing according to claim 5, characterized in that: The calculation method for determining the coefficient of variation of crack extension length by a single blasthole area increment is: Through △S i Calculate the ratio of the area increment of the blasthole to the sum of the area increments of all blastholes: △S i / ∑ n △S i ; Arrange the ratios in ascending order, so that n groups can be obtained, which are: Calculate (X i , Y i ), the Lorentz curve for evaluating the heterogeneity of the extension length of a single crack is obtained, and the equation is: Then the coefficient of variation is:

7. A method for calculating the size and amount of temporary plugging balls for shale gas fracturing according to claim 6, characterized in that: The calculation of the temporary blocking ball pitch size d1 and the temporary blocking ball quantity a1 includes the following steps: C1. According to the design length L of each cluster of cracks 1.i Calculate the coefficient of variation of crack length with reference to the standard V' k ; C2. Determine the heterogeneous elastic interval ψ of crack extension based on actual engineering conditions and eliminate data; C3. Perform temporary plugging fracturing to further transform underdeveloped fractures and determine the values ​​of the temporary plugging ball size d1 and the number of temporary plugging balls a1.

8. A method for calculating the size and amount of temporary plugging balls for shale gas fracturing according to claim 7, characterized in that: Crack length variation coefficient refers to standard V' k The equation is:

9. A method for calculating the size and amount of temporary plugging balls for shale gas fracturing according to claim 8, characterized in that: In step C3, the range of the blocking ball pitching size d1 and the numerical calculation method of the temporary blocking ball quantity a1 are as follows: When (V' k +ψ)≤V k ≤1; The temporary plugging ball size d1 is not less than the maximum blasthole size during temporary plugging: d1≥max(d 1.1 、d 1.2 …d 1.n ); The number of temporarily blocked balls a1 is: a1=(V k -V' k +ψ)n.

10. A method for calculating the size and amount of temporary plugging balls for shale gas fracturing according to claim 9, characterized in that: The calculation method of the ball blocking pitch size d1 is: According to the variation coefficient of the blasthole area increment and the variation coefficient of the crack length, refer to the standard V' k The number of temporary plugging balls calculated from the number of perforations in the target layer is rounded up to: b1=rouundup(a1,0).

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