A method and system for calculating wellbore friction during a fracturing operation

Abstract

This invention pertains to the field of oil extraction. To address the problem of excessive calculations required for construction parameters, it provides a method and system for calculating wellbore friction during fracturing operations. The system acquires fracturing data in real time, including fracturing fluid type, proppant type, proppant concentration, and fracturing fluid flow rate. Based on the fracturing fluid type, proppant type, proppant concentration, and fracturing fluid flow rate at each moment during fracturing operations, the actual wellbore friction at each moment is calculated. This is based on the drag reduction rate of the fracturing fluid and the friction Pf of the clean water. w Calculate the frictional resistance Pf of the fracturing fluid without proppant. l The proppant friction coefficient A is calculated using the proppant friction coefficient calculation formula based on the proppant concentration; the proppant friction coefficient is compared with the friction coefficient Pf of the fracturing working fluid without proppant. l Calculate the frictional resistance of the fracturing working fluid carrying the proppant, i.e., the actual wellbore frictional resistance Pf.

Description

Technical Field

[0001] This invention belongs to the field of oil extraction, specifically relating to a method and system for calculating wellbore friction during fracturing operations. Background Technology

[0002] Fracturing is a process that artificially creates fractures in the formation to improve the underground flow environment of oil and increase well production. Fracturing pressure refers to the wellhead pressure during the fracturing operation. It is one of the main input parameters in post-fracturing analysis. Influenced by various factors, the fracturing pressure constantly changes during the fracturing process. Among these factors, changes in wellbore friction are one that causes variations in wellhead pump pressure, affecting the fracturing pressure analysis and constituting a interference factor. Therefore, understanding the changes in wellbore friction during fracturing is crucial for using fracturing pressure to determine the formation response during fracturing, analyze fracture propagation patterns, and determine fracture geometry.

[0003] Currently, existing methods for calculating wellbore friction in fracturing operations have achieved certain results in fracturing practice, but they also have many limitations, such as:

[0004] 1) The calculation method is complex, requires many parameters that are difficult to obtain, and is difficult to apply.

[0005] 2) It can only estimate the wellbore friction value at a single moment, and cannot obtain the continuous change curve of wellbore friction during the construction process.

[0006] 3) The calculation results cannot truly reflect the wellbore friction. For example, Chinese patent publication CN1121445167A discloses a method for calculating dynamic bottom hole pressure of fracturing based on construction data. It uses the friction calculation formula fitted by the indoor experiment to correct the friction in the field construction, but only considers the friction generated by the fracturing fluid and ignores the friction generated by the proppant.

[0007] The Chinese publication "Calculation of Frictional Resistance of Fracturing Tubing String in Fracturing Operation, Inner Mongolia Petroleum and Chemical Industry, 1006-7981(2015)19-0078-02" discloses the calculation of frictional resistance of fracturing tubing strings, which is of great significance for judging pressure fluctuations and fitting the net pressure after fracturing. Currently, the calculation of frictional resistance of fracturing fluid in laminar flow is relatively mature, and the calculation results are highly reliable. However, the properties of fracturing fluid in turbulent flow have not yet been determined, resulting in larger errors in the frictional resistance calculation results. This publication uses the drag reduction ratio method to calculate the frictional resistance of fracturing tubing strings, and improves the calculation accuracy by comparing theoretical calculations with field measured data. However, it requires many parameters, which are sometimes difficult to meet on-site conditions, making it inconvenient to use.

[0008] The Chinese publicly available literature, "Research on Quantitative Calculation Model of Friction Resistance of Propellant-Carrying Fluid in Horizontal Well Fracturing," Journal of Southwest Petroleum University, Vol. 33 No. 6 Dec. 2011, discloses a method using the momentum exchange theory between liquid and solid two-phase flows to study the average flow velocity of proppant-carrying fluid in vertical, build-up, and horizontal well sections under suspended, slip-and-jump, and partially suspended / slip-and-jump states. Finally, the Darcy-Weisbach formula was used to establish a friction resistance calculation model for proppant-carrying fluid applicable to various well types, and the effects of pipe diameter, flow rate, proppant ratio, fracturing fluid, and proppant properties on friction resistance were calculated and analyzed. However, this method requires many parameters, which are sometimes difficult to meet in field conditions, making it inconvenient to use.

[0009] Therefore, it is necessary to study and propose a new method for calculating wellbore friction during fracturing operations to address the limitations of the aforementioned problems. Summary of the Invention

[0010] The purpose of this invention is to solve the problems existing in the prior art and, in view of the limitations of conventional fracturing wellbore friction calculation methods, to provide a method and system for calculating wellbore friction during fracturing operations. This method can quickly obtain the wellbore friction change curve during fracturing operations using less fracturing operation data, thereby improving the accuracy of wellbore friction calculation, eliminating the influence of wellbore friction on pressure analysis, and effectively improving the reliability of post-fracturing analysis.

[0011] This invention is achieved through the following technical solution: a method for calculating wellbore friction during fracturing operations, which calculates the friction of clean water, obtains the friction of fracturing working fluid without proppant based on the friction reduction rate of the fracturing working fluid, and obtains the friction of fracturing working fluid with proppant based on the friction coefficient of the proppant based on the friction of the fracturing working fluid without proppant, i.e., the actual wellbore friction.

[0012] Furthermore, the calculation method for wellbore friction during fracturing includes the following steps:

[0013] Real-time acquisition of fracturing operation data, including fracturing fluid type, proppant type, proppant concentration, and fracturing fluid discharge rate;

[0014] Based on the fracturing fluid type, proppant type, proppant concentration, and fracturing fluid discharge rate at each moment during the fracturing operation, the actual wellbore friction at each moment during the fracturing operation is calculated, including the following steps:

[0015] Calculate the water friction Pf in the wellbore under the same fracturing fluid displacement using the formula for calculating water friction. w ;

[0016] The drag reduction rate k of the fracturing working fluid is calculated using the fracturing working fluid drag reduction rate calculation formula based on the type and flow rate of the fracturing working fluid.

[0017] Based on the drag reduction rate of fracturing working fluid and the frictional resistance Pf of water w Calculate the frictional resistance Pf of the fracturing fluid without proppant. l ;

[0018] The friction coefficient A of the proppant is calculated based on the proppant concentration using the formula for calculating the friction coefficient of the proppant.

[0019] Based on the friction coefficient of the proppant and the friction Pf of the fracturing fluid without proppant... l Calculate the frictional resistance of the fracturing working fluid carrying the proppant, i.e., the actual wellbore frictional resistance Pf.

[0020] Furthermore, the frictional resistance Pf of clear water w The calculation formula is as follows: Pf w =1.385×10 6 D -4.8 ×Q 1.8 ×H;

[0021] In the formula, D represents the inner diameter of the wellbore, H represents the length of the wellbore, and Q represents the fracturing working fluid discharge rate.

[0022] Furthermore, the drag reduction rate of different types of fracturing working fluids under different flow rates was obtained from historical fracturing operation data. The calculation formula for the drag reduction rate k of different types of fracturing working fluids was obtained through linear regression, and the general formula is as follows:

[0023] k = f(Q) = a0 * a1Q 1 +a2*Q 2 +···+a n *Q n ;

[0024] In the formula, Q represents the fracturing working fluid discharge rate, and a0, a1, a2, ..., a n All of these represent regression coefficients.

[0025] Furthermore, the frictional resistance Pf of the fracturing fluid without proppant l =f(Q)·Pf w .

[0026] Furthermore, by testing the frictional resistance of different types of proppant at different proppant concentrations, the formula for calculating the frictional resistance coefficient of different types of proppant at different proppant concentrations was obtained through linear regression. The general formula is as follows: A=d*(1+C) e ;

[0027] In the formula, A represents the proppant friction coefficient, C represents the proppant concentration, and d and e represent regression coefficients.

[0028] Furthermore, the actual wellbore friction Pf = A·Pf l .

[0029] Furthermore, by using the calculated actual wellbore friction at each moment during the fracturing process, a curve showing the change in wellbore friction over time was obtained.

[0030] Furthermore, the fracturing fluid discharge and proppant concentration at each moment during the fracturing operation are obtained through second-point data.

[0031] Furthermore, the type of fracturing working fluid and proppant at each moment during the fracturing operation can be obtained through the pump injection procedure record table.

[0032] This invention also provides a system for calculating wellbore friction during fracturing operations, comprising the following modules:

[0033] The real-time fracturing operation data acquisition module is used to obtain the fracturing working fluid type and proppant type at each moment during the fracturing operation from the second-point data, and to obtain the proppant concentration and fracturing working fluid discharge rate at each moment during the fracturing operation from the pumping process record table.

[0034] The clean water friction calculation module is used to calculate the clean water friction Pf in the same wellbore under the same fracturing working fluid displacement, based on the clean water friction calculation formula. w ;

[0035] The fracturing working fluid drag reduction calculation module calculates the fracturing working fluid drag reduction rate k based on the fracturing working fluid type and fracturing working fluid discharge rate using the fracturing working fluid drag reduction rate calculation formula.

[0036] The module for calculating the friction resistance of fracturing working fluid without proppant is used to calculate the friction resistance of fracturing working fluid and the friction resistance Pf of clean water. w Calculate the frictional resistance Pf of the fracturing fluid without proppant. l ;

[0037] The proppant friction coefficient calculation module is used to calculate the proppant friction coefficient A based on the proppant concentration using the proppant friction coefficient calculation formula.

[0038] The actual wellbore friction calculation module is used to calculate the friction coefficient of the proppant and the friction Pf of the fracturing working fluid without proppant. l Calculate the frictional resistance of the fracturing working fluid carrying the proppant, i.e., the actual wellbore frictional resistance Pf.

[0039] Compared with the prior art, the beneficial effects of the present invention include:

[0040] 1. This invention uses fewer parameters, requiring only wellbore dimensions and fracturing fluid type, proppant type, proppant concentration, and fracturing fluid discharge rate from the fracturing construction data. The fracturing construction data can be acquired in real time, thus enabling the calculation of the actual wellbore friction at each moment during the fracturing process, which can then be used to analyze the wellhead pressure generated throughout the entire fracturing process.

[0041] 2. This invention is based on the drag reduction method, which calculates the friction of fracturing working fluid with proppant step by step from the friction of clear water and the friction of fracturing working fluid without proppant by the drag reduction rate. It takes into account the influence of proppant and improves the accuracy of the calculation results.

[0042] 3. This invention uses linear regression to obtain the calculation formulas for the drag reduction rate of fracturing working fluid and the friction coefficient of proppant, thereby enabling rapid calculation of the drag reduction rate of different types of fracturing working fluid at different flow rates and the friction coefficient of different types of proppant at different concentrations, adapting to the constantly changing situation of fracturing working fluid and proppant during construction.

[0043] 4. This invention is reasonably designed, has a clear method, is simple and efficient, and can quickly estimate the wellbore friction change curve during the fracturing process using fracturing construction data, eliminating the influence of wellbore friction on pressure analysis and improving the reliability of post-fracturing pressure analysis. Attached Figure Description

[0044] Figure 1 This is a flowchart for calculating the actual wellbore friction at each moment in this specific embodiment. Detailed Implementation

[0045] This invention patent relates to a method for estimating the wellbore friction variation curve during the construction process using on-site construction data, which is applicable to various types of oil and gas reservoirs.

[0046] The overall concept of this invention is:

[0047] 1) Real-time acquisition of fracturing operation data, including fracturing fluid type, proppant type, proppant concentration, and fracturing fluid discharge rate. Specifically: fracturing fluid discharge rate and proppant concentration are acquired at each moment during the fracturing operation through second-point data; fracturing fluid type and proppant type are acquired at each moment during the fracturing operation through the pumping procedure record table.

[0048] 2) Calculate the frictional resistance of clean water under the same conditions (same displacement, wellbore length, and inner diameter). Assuming that the pumped fluid is clean water and no proppant is added, calculate the frictional resistance of clean water using the wellbore dimensions, working fluid displacement, and the formula for calculating frictional resistance of clean water.

[0049] 3) Calculate the actual wellbore friction during pumping. Based on the drag reduction method, the friction of the fracturing working fluid with proppant is calculated step by step from the friction of clean water and the friction of the fracturing working fluid without proppant by the drag reduction rate. The influence of proppant is taken into account, which improves the accuracy of the calculation results.

[0050] The linear regression method yields the calculation formulas for the drag reduction rate of fracturing working fluid and the friction coefficient of proppant, thus enabling rapid calculation of the drag reduction rate of different types of fracturing working fluid at different flow rates and the friction coefficient of different types of proppant at different concentrations, adapting to the constantly changing situation of fracturing working fluid and proppant during construction.

[0051] The frictional resistance of water, the drag reduction rate of fracturing working fluid, and the frictional resistance coefficient of proppant can be calculated in series or in parallel. Parallel calculation is preferred because it has higher calculation efficiency and better real-time performance.

[0052] The present invention will now be described in more detail with reference to the embodiments.

[0053] Example 1

[0054] refer to Figure 1 As shown, a method for calculating wellbore friction during fracturing operations includes the following steps:

[0055] Real-time acquisition of fracturing operation data, including fracturing fluid type, proppant type, proppant concentration, and fracturing fluid discharge rate;

[0056] Based on the fracturing fluid type, proppant type, proppant concentration, and fracturing fluid discharge rate at each moment during the fracturing operation, the actual wellbore friction at each moment during the fracturing operation is calculated, including the following steps:

[0057] Calculate the water friction Pf in the wellbore under the same fracturing fluid displacement using the formula for calculating water friction. w ; Water friction Pf w The calculation formula is as follows:

[0058] Pf w =1.385×10 6 D -4.8 ×Q 1.8 ×H;

[0059] In the formula, D represents the inner diameter of the wellbore, H represents the length of the wellbore, and Q represents the fracturing working fluid discharge rate.

[0060] The drag reduction rate k of the fracturing working fluid is calculated using the fracturing working fluid drag reduction rate calculation formula based on the type and flow rate of the fracturing working fluid.

[0061] The drag reduction rate of different types of fracturing working fluids at different flow rates was obtained from historical fracturing operation data. The formula for calculating the drag reduction rate k of different types of fracturing working fluids was obtained through linear regression, and the general formula is as follows: k = f(Q) = a0 * a1Q 1 +a2*Q 2 +···+a n *Q n In the formula, Q represents the fracturing working fluid discharge rate, and a0, a1, a2, ..., a n All of these represent regression coefficients.

[0062] Based on the drag reduction rate of fracturing working fluid and the frictional resistance Pf of water w Calculate the frictional resistance Pf of the fracturing fluid without proppant. l Frictional resistance Pf of fracturing fluid without proppant l =f(Q)·Pf w .

[0063] The friction coefficient A of the proppant is calculated using the formula for calculating the friction coefficient of the proppant based on the proppant concentration. By testing the friction of different types of proppant at different proppant concentrations, the formula for calculating the friction coefficient of different types of proppant at different proppant concentrations is obtained through linear regression. The general formula is as follows:

[0064] A = d*(1+C) e ;

[0065] In the formula, A represents the proppant friction coefficient, C represents the proppant concentration, and d and e represent regression coefficients.

[0066] Based on the friction coefficient of the proppant and the friction Pf of the fracturing fluid without proppant... l Calculate the frictional resistance of the fracturing fluid carrying the proppant, i.e., the actual wellbore frictional resistance Pf. Actual wellbore frictional resistance Pf = A·Pf l .

[0067]

Example 2

[0068] The actual wellbore friction at each moment during the fracturing process is calculated using the calculation method of wellbore friction during fracturing construction in Example 1. The curve of wellbore friction change with time is obtained by fitting, and MATLAB can be used for fitting.

[0069] The wellbore friction variation curve can be used to intuitively and quickly obtain the wellbore friction during the fracturing process, eliminate the influence of wellbore friction on pressure analysis, and improve the reliability of post-fracturing pressure analysis.

[0070]

Example 3

[0071] A system for calculating wellbore friction during fracturing operations, comprising the following modules:

[0072] The real-time fracturing operation data acquisition module is used to obtain the fracturing working fluid type and proppant type at each moment during the fracturing operation from the second-point data, and to obtain the proppant concentration and fracturing working fluid discharge rate at each moment during the fracturing operation from the pumping process record table.

[0073] The clean water friction calculation module is used to calculate the clean water friction Pf in the same wellbore under the same fracturing working fluid displacement, based on the clean water friction calculation formula. w ;

[0074] Clear water friction Pf w The calculation formula is as follows:

[0075] Pf w =1.385×10 6 D -4.8 ×Q 1.8 ×H;

[0076] In the formula, D represents the inner diameter of the wellbore, H represents the length of the wellbore, and Q represents the fracturing working fluid discharge rate.

[0077] The fracturing working fluid drag reduction calculation module calculates the fracturing working fluid drag reduction rate k based on the fracturing working fluid type and fracturing working fluid discharge rate using the fracturing working fluid drag reduction rate calculation formula.

[0078] The drag reduction rate of different types of fracturing working fluids at different flow rates was obtained from historical fracturing operation data. The formula for calculating the drag reduction rate k of different types of fracturing working fluids was obtained through linear regression, and the general formula is as follows: k = f(Q) = a0 * a1Q 1 +a2*Q 2 +···+a n *Q n In the formula, Q represents the fracturing working fluid discharge rate, and a0, a1, a2, ..., a n All of these represent regression coefficients.

[0079] The module for calculating the friction resistance of fracturing working fluid without proppant is used to calculate the friction resistance of fracturing working fluid and the friction resistance Pf of clean water. w Calculate the frictional resistance Pf of the fracturing fluid without proppant. l Frictional resistance Pf of fracturing fluid without proppant l =f(Q)·Pf w .

[0080] The proppant friction coefficient calculation module is used to calculate the proppant friction coefficient A based on the proppant concentration using the proppant friction coefficient calculation formula.

[0081] By testing the frictional resistance of different types of proppant at different proppant concentrations, the formula for calculating the frictional resistance coefficient of different types of proppant at different proppant concentrations was obtained through linear regression. The general formula is as follows:

[0082] A = d*(1+C) e ;

[0083] In the formula, A represents the proppant friction coefficient, C represents the proppant concentration, and d and e represent regression coefficients.

[0084] The actual wellbore friction calculation module is used to calculate the friction coefficient of the proppant and the friction Pf of the fracturing working fluid without proppant. l Calculate the frictional resistance of the fracturing fluid carrying the proppant, i.e., the actual wellbore frictional resistance Pf. Actual wellbore frictional resistance Pf = A·Pf l .

[0085]

Example 4

[0086] The wellbore friction calculation system used in Example 3 includes a monitoring module, which controls the other modules to work together to calculate the actual wellbore friction at each moment during the fracturing process based on the type of fracturing fluid, the type of proppant, the concentration of proppant, and the discharge rate of fracturing fluid at each moment, thereby monitoring the wellbore friction generated throughout the fracturing process.

[0087] The monitoring module controls the collaboration of each module in the following manner:

[0088] Real-time fracturing operation data acquisition module:

[0089] Real-time acquisition of fracturing operation data, including fracturing fluid type, proppant type, proppant concentration, and fracturing fluid discharge rate.

[0090] Clear water friction calculation module:

[0091] The water friction Pf in the same wellbore under the same fracturing fluid displacement was calculated using the water friction calculation formula. w ;

[0092] Clear water friction Pf w The calculation formula is as follows:

[0093] Pf w =1.385×10 6 D -4.8 ×Q 1.8 ×H;

[0094] In the formula, D represents the inner diameter of the wellbore, H represents the length of the wellbore, and Q represents the fracturing working fluid discharge rate.

[0095] Fracturing working fluid drag reduction calculation module:

[0096] The drag reduction rate k of the fracturing working fluid is calculated using the fracturing working fluid drag reduction rate calculation formula based on the type and flow rate of the fracturing working fluid.

[0097] The drag reduction rate of different types of fracturing working fluids at different flow rates was obtained from historical fracturing operation data. The formula for calculating the drag reduction rate k of different types of fracturing working fluids was obtained through linear regression, and the general formula is as follows: k = f(Q) = a0 * a1Q 1 +a2*Q 2 +···+a n *Q n In the formula, Q represents the fracturing working fluid discharge rate, and a0, a1, a2, ..., a n All of these represent regression coefficients.

[0098] Module for calculating friction resistance of fracturing fluid without proppant:

[0099] Based on the drag reduction rate of fracturing working fluid and the frictional resistance Pf of water w Calculate the frictional resistance Pf of the fracturing fluid without proppant. l Frictional resistance Pf of fracturing fluid without proppant l =f(Q)·Pf w .

[0100] Propion friction coefficient calculation module:

[0101] The friction coefficient A of the proppant is calculated based on the proppant concentration using the formula for calculating the friction coefficient of the proppant.

[0102] By testing the frictional resistance of different types of proppant at different proppant concentrations, the formula for calculating the frictional resistance coefficient of different types of proppant at different proppant concentrations was obtained through linear regression. The general formula is as follows:

[0103] A = d*(1+C) e ;

[0104] In the formula, A represents the proppant friction coefficient, C represents the proppant concentration, and d and e represent regression coefficients.

[0105] Actual wellbore friction calculation module:

[0106] Based on the friction coefficient of the proppant and the friction Pf of the fracturing fluid without proppant l Calculate the frictional resistance of the fracturing fluid carrying the proppant, i.e., the actual wellbore frictional resistance Pf. Actual wellbore frictional resistance Pf = A·Pf l .

[0107] Example 5

[0108] Based on Example 4, a wellbore friction variation curve generation module is added. This module is used to obtain the wellbore friction variation curve over time by fitting the actual wellbore friction at each moment, which can be done using MATLAB.

[0109] The wellbore friction variation curve can be used to intuitively and quickly obtain the wellbore friction during the fracturing process, eliminate the influence of wellbore friction on pressure analysis, and improve the reliability of post-fracturing pressure analysis.

[0110] As can be seen from the above embodiments, the present invention has the following advantages:

[0111] This invention uses fewer parameters, requiring only wellbore dimensions and fracturing fluid type, proppant type, proppant concentration, and fracturing fluid discharge rate from the fracturing operation data. The fracturing operation data can be acquired in real time, thus enabling the calculation of the actual wellbore friction at each moment during the fracturing operation, which can then be used to analyze the wellhead pressure generated throughout the entire fracturing operation.

[0112] This invention is based on the drag reduction method, which calculates the friction of fracturing fluid with proppant step by step from the friction of water and the friction of fracturing fluid without proppant by the drag reduction rate. It takes into account the influence of proppant and improves the accuracy of the calculation results.

[0113] This invention uses a linear regression method to obtain calculation formulas for the drag reduction rate of fracturing working fluid and the friction coefficient of proppant, thereby enabling rapid calculation of the drag reduction rate of different types of fracturing working fluid at different flow rates and the friction coefficient of different types of proppant at different concentrations, adapting to the constantly changing situation of fracturing working fluid and proppant during construction.

[0114] This invention is rationally designed, has a clear method, is simple and efficient, and can quickly estimate the wellbore friction change curve during the fracturing process using fracturing construction data, thereby eliminating the influence of wellbore friction on pressure analysis and improving the reliability of post-fracturing pressure analysis.

[0115] Finally, it should be noted that the above technical solution is only one embodiment of the present invention. For those skilled in the art, based on the application methods and principles disclosed in the present invention, it is easy to make various types of improvements or modifications, and not limited to the methods described in the above specific embodiments of the present invention. Therefore, the methods described above are only preferred and have no limiting significance.

Claims

1. A method for calculating wellbore friction during fracturing operations, characterized in that, Calculate the frictional resistance of the clean water. Based on the frictional resistance of the clean water, obtain the frictional resistance of the fracturing working fluid without proppant based on the drag reduction rate of the fracturing working fluid. Based on the frictional resistance of the fracturing working fluid without proppant, obtain the frictional resistance of the fracturing working fluid with proppant based on the proppant friction coefficient, i.e., the actual wellbore frictional resistance. This includes the following steps: Real-time acquisition of fracturing operation data, including fracturing fluid type, proppant type, proppant concentration, and fracturing fluid discharge rate; Based on the type of fracturing fluid, the type of proppant, the concentration of proppant, and the flow rate of fracturing fluid at each moment during the fracturing operation, the actual wellbore friction at each moment during the fracturing operation is calculated, including the following steps: Calculate the water friction Pf in the wellbore under the same fracturing fluid displacement using the formula for calculating water friction. w ; The drag reduction rate (k) of the fracturing fluid is calculated using the fracturing fluid drag reduction rate calculation formula based on the fracturing fluid type and flow rate. The drag reduction rates of different types of fracturing fluids at different flow rates are obtained from historical fracturing operation data. The calculation formula for the drag reduction rate (k) of different types of fracturing fluids is obtained through linear regression, and the general formula is as follows: k=f(Q)=a0*a1Q 1 +a2*Q 2 +···+a n *Q n ; In the formula, Q represents the fracturing working fluid discharge rate, and a0, a1, a2, ..., a n All represent regression coefficients; Based on the drag reduction rate of fracturing working fluid and the frictional resistance Pf of water w Calculate the frictional resistance Pf of the fracturing fluid without proppant. l :Pf l =f(Q)·Pf w ; The friction coefficient A of the proppant is calculated based on the proppant concentration using the formula for calculating the proppant friction coefficient. By testing the friction of different types of proppant at different proppant concentrations, the formula for calculating the friction coefficient of different types of proppant at different proppant concentrations is obtained through linear regression. The general formula is as follows: A=d*(1+C) e ; In the formula, A represents the proppant friction coefficient, C represents the proppant concentration, and d and e both represent regression coefficients; Based on the friction coefficient of the proppant and the friction Pf of the fracturing fluid without proppant... l Calculate the frictional resistance of the fracturing fluid carrying the proppant, i.e., the actual wellbore frictional resistance Pf: Pf = A·Pf l .

2. The method for calculating wellbore friction during fracturing operations according to claim 1, characterized in that, Clear water friction Pf w The calculation formula is as follows: Pf w =1.385×10 6 D -4.8 ×Q 1.8 ×H; In the formula, D represents the inner diameter of the wellbore, H represents the length of the wellbore, and Q represents the fracturing working fluid discharge rate.

3. The method for calculating wellbore friction during fracturing operations according to claim 1, characterized in that, By using the calculated actual wellbore friction at each moment during the fracturing process, a curve showing the change in wellbore friction over time was obtained.

4. The method for calculating wellbore friction during fracturing operations according to claim 1, characterized in that, The fracturing fluid discharge and proppant concentration at every moment during the fracturing operation are obtained by using second-point data.

5. The method for calculating wellbore friction during fracturing operations according to claim 1, characterized in that, The type of fracturing working fluid and proppant type at each moment during the fracturing operation can be obtained by using the pumping procedure record table.

6. A calculation system for wellbore friction during fracturing operations, used to implement the method described in any one of claims 1-5, characterized in that, Includes the following modules: The real-time fracturing operation data acquisition module is used to obtain the fracturing working fluid type and proppant type at each moment during the fracturing operation from the second-point data, and to obtain the proppant concentration and fracturing working fluid discharge rate at each moment during the fracturing operation from the pumping process record table. The clean water friction calculation module is used to calculate the clean water friction Pf in the same wellbore under the same fracturing working fluid displacement, based on the clean water friction calculation formula. w ; The fracturing working fluid drag reduction calculation module calculates the fracturing working fluid drag reduction rate k based on the fracturing working fluid type and fracturing working fluid discharge rate using the fracturing working fluid drag reduction rate calculation formula. The module for calculating the friction resistance of fracturing working fluid without proppant is used to calculate the friction resistance of fracturing working fluid and the friction resistance Pf of clean water. w Calculate the frictional resistance Pf of the fracturing fluid without proppant. l ; The proppant friction coefficient calculation module is used to calculate the proppant friction coefficient A based on the proppant concentration using the proppant friction coefficient calculation formula. The actual wellbore friction calculation module is used to calculate the friction coefficient of the proppant and the friction Pf of the fracturing working fluid without proppant. l Calculate the frictional resistance of the fracturing working fluid carrying the proppant, i.e., the actual wellbore frictional resistance Pf.

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