Method and device for evaluating the frictional resistance of drag-reducing water, storage medium and electronic device

Abstract

This invention relates to the field of oil and gas field development technology, and particularly to a method for evaluating the friction loss of drag-reducing water. The method involves acquiring the discharge rate, friction-perforation friction, and tortuous friction of drag-reducing water of a first viscosity at each fracturing section during pump shutdown; acquiring data from a reduction discharge test based on drag-reducing water of the first and second viscosities in a selected fracturing section; acquiring the mid-depth sounding of each fracturing section; and calculating the friction loss coefficient gradient of the first viscosity drag-reducing water, as well as the perforation friction coefficient and tortuous friction coefficient of the first viscosity drag-reducing water in each fracturing section based on the mid-depth sounding and the discharge rate, friction-perforation friction, and tortuous friction of the first viscosity drag-reducing water in each fracturing section. Finally, based on the reduction discharge test data, the friction loss coefficient gradient of the first viscosity drag-reducing water, and the perforation friction coefficient and tortuous friction coefficient of the first viscosity drag-reducing water in the selected fracturing section, the friction loss coefficient gradient of the second viscosity drag-reducing water is calculated.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field development technology, and in particular to a method, apparatus, storage medium, and electronic equipment for evaluating frictional resistance along the path of drag-reducing water. Background Technology

[0002] By adding different concentrations of variable viscosity and drag-reducing agents to the integrated variable viscosity drag-reducing water system, drag-reducing water with different viscosities can be obtained. This allows for real-time online mixing of fracturing fluid viscosity during fracturing operations, making the operation convenient and quick.

[0003] Because the frictional resistance of fracturing fluids with different viscosities varies significantly, especially the viscosity of the integrated viscosity-modifying and drag-reducing water varies considerably throughout the fracturing process depending on the concentration of the added viscosity-modifying and drag-reducing agent, accurate assessment of the frictional resistance of the integrated viscosity-modifying and drag-reducing water at different concentrations of the added viscosity-modifying and drag-reducing agent is crucial for predicting construction risks and improving the accuracy of fracturing design parameters. However, current evaluation methods suffer from technical problems such as difficulty in widespread application, large errors, high costs, and / or complex procedures.

[0004] There is an urgent need in this field for a simple, economical and rapid evaluation method to conduct on-site evaluation of the frictional resistance along the path of integrated variable viscosity drag-reducing water. Summary of the Invention

[0005] This invention provides a method, apparatus, storage medium, and electronic device for evaluating friction along the path of drag-reducing water, solving the technical problem of difficulty in conducting on-site evaluation of friction along the path of integrated variable viscosity drag-reducing water.

[0006] In a first aspect, the present invention provides a method for evaluating the frictional resistance along the path of variable viscosity drag-reducing water, comprising:

[0007] The discharge rate, friction-perforation friction, and tortuous friction of the first viscosity drag-reducing water at the pump stop time in each fracturing section were obtained, and the data of the discharge rate reduction test based on the first viscosity drag-reducing water and the second viscosity drag-reducing water were obtained in the selected fracturing section.

[0008] Obtain the mid-depth of each fracturing section. Based on the mid-depth of each fracturing section and the discharge rate, friction-perforation friction and tortuosity friction of the first viscosity drag-reducing water at the pump stop time in each fracturing section, calculate the friction coefficient gradient of the first viscosity drag-reducing water and the perforation friction coefficient and tortuosity friction coefficient of the first viscosity drag-reducing water in each fracturing section.

[0009] Based on the data from the reduced discharge test, the friction coefficient gradient of the first viscosity drag-reducing water, and the perforation friction coefficient and tortuosity friction coefficient of the first viscosity drag-reducing water in the selected fracturing section, the friction coefficient gradient of the second viscosity drag-reducing water is calculated to complete the evaluation of the friction coefficient of the variable viscosity drag-reducing water.

[0010] In some embodiments, obtaining the discharge rate, friction-perforation friction, and tortuous friction of the first viscosity drag-reducing water at the pump shutdown time in each fracturing stage includes:

[0011] After the fracturing operation of each fracturing section is completed, the pump is stopped and the pressure drop is measured, and the data at the second point of pump stoppage is recorded.

[0012] The double logarithmic pressure difference derivative curve of the fracturing section was plotted based on the pump shutdown time data.

[0013] The frictional resistance along the fracturing section and the tortuous frictional resistance are calculated based on the pressure corresponding to the pressure at the moment of pump shutdown and the pressure corresponding to the first hump of the double logarithmic pressure difference derivative curve.

[0014] In some embodiments, the frictional resistance along the fracturing section and the tortuous frictional resistance are calculated based on the pressure corresponding to the pressure at the time of pump shutdown and the pressure corresponding to the first peak of the double logarithmic pressure difference derivative curve, including:

[0015] The pressure at the moment of pump shutdown is calculated as the pressure at the moment when the first hump of the double logarithmic pressure difference derivative curve appears, and the frictional resistance along the fracturing section is obtained.

[0016] The tortuous friction of the fracturing section is obtained by calculating the pressure at the first peak of the double logarithmic pressure difference derivative curve and the pressure at the end of the first peak.

[0017] In some embodiments, based on the mid-depth sounding of each fracturing section and the discharge rate, friction-perforation friction, and tortuous friction of the first viscosity drag-reducing water at the pump shutdown time in each fracturing section, the friction coefficient gradient of the first viscosity drag-reducing water and the perforation friction coefficient and tortuous friction coefficient of the first viscosity drag-reducing water in each fracturing section are calculated, including:

[0018] The friction coefficient and tortuous friction coefficient of the first viscosity drag-reducing water in each fracturing section are calculated based on the pump stop time discharge rate, friction-perforation friction, and tortuous friction of the first viscosity drag-reducing water in each fracturing section.

[0019] The friction coefficient gradient of the first viscosity drag-reducing water is obtained based on the mid-depth sounding of each fracturing section and the friction coefficient along the perforation.

[0020] In some embodiments, based on the mid-depth sounding of each fracturing section and the discharge rate, friction-perforation friction, and tortuosity friction of the first viscosity drag-reducing water at the pump shutdown time in each fracturing section, the friction coefficient gradient of the first viscosity drag-reducing water and the perforation friction coefficient and tortuosity friction coefficient of the first viscosity drag-reducing water in each fracturing section, the calculation further includes:

[0021] The perforation friction coefficient of each fracturing section is obtained based on the friction coefficient gradient along the path of the first viscosity drag-reducing water and the mid-depth measurement of each fracturing section.

[0022] In some embodiments, the friction-to-perforation friction coefficient and the tortuous friction coefficient of the first viscosity drag-reducing water in each fracturing section are calculated based on the pump stop rate, friction-to-perforation friction, and tortuous friction at each fracturing section, including:

[0023] The friction coefficient along the perforation of the first viscosity drag-reducing water in each fracturing stage is calculated using the following expression:

[0024] α= P well-perf / Q 2

[0025] Where α is the friction coefficient along the perforation path, and P well-perf Let Q be the frictional resistance along the perforation path, and Q be the discharge rate at the moment the pump stops.

[0026] In some embodiments, the friction-to-perforation friction coefficient and the tortuous friction coefficient of the first viscosity drag-reducing water in each fracturing section are calculated based on the pump stop rate, friction-to-perforation friction, and tortuous friction at each fracturing section, including:

[0027] The tortuous friction coefficient of the first viscosity drag-reducing water in each fracturing stage is calculated using the following expression:

[0028] β=P tort / Q 0.5

[0029] Where β is the tortuosity friction coefficient, P tort For tortuous friction, Q is the discharge rate at the moment the pump stops.

[0030] In some embodiments, the friction coefficient gradient of the first viscosity drag-reducing water is obtained based on the mid-depth sounding of each fracturing section and the friction coefficient along the perforation path, including:

[0031] The friction coefficient gradient along the frictional path of the first viscosity drag-reducing water in each fracturing stage is calculated using the following expression:

[0032] λ i =α i / H i

[0033] Where i is the fracturing segment number, 1≤i≤n, and n is the total number of fracturing segments; α i H is the friction coefficient along the perforation path of the i-th fracturing section; i The depth is measured at the middle of the i-th fracturing segment.

[0034] In some embodiments, the friction coefficient gradient of the first viscosity drag-reducing water is obtained based on the mid-depth sounding of each fracturing section and the friction coefficient along the perforation path, further comprising:

[0035] The minimum value among the friction coefficient gradients along the friction-perforation coefficient of each fracturing section is taken as the friction coefficient gradient along the friction of the first viscosity drag-reducing water.

[0036] In some embodiments, the selected fracturing segment is any one of the fracturing segments selected from the various fracturing segments;

[0037] Data on displacement reduction tests based on first-viscosity drag-reducing water and second-viscosity drag-reducing water were obtained in selected fracturing sections, including:

[0038] After selecting the fracturing section and recording the pump stop time data, restart the pump;

[0039] Pump the first viscosity drag-reducing water at the first displacement Q(A) and obtain the first pressure P(A) after the pressure stabilizes;

[0040] Pump the second viscosity drag-reducing water at the second displacement Q(B1). After pumping one wellbore volume of liquid, record the stable second pressure P(B1).

[0041] A second viscosity drag-reducing water was pumped at a third displacement Q(B2) that was less than the second displacement to conduct a displacement reduction test and obtain a stable third pressure P(B2).

[0042] In some embodiments, based on data from the reduction in discharge rate test, the friction coefficient gradient of the first viscosity drag-reducing water along the path, and the perforation friction coefficient and tortuosity friction coefficient of the first viscosity drag-reducing water in a selected fracturing section, the friction coefficient gradient of the second viscosity drag-reducing water along the path is calculated, including:

[0043] The friction coefficient gradient along the path of the second viscosity drag-reducing water is calculated using the following expression:

[0044] H3λ A Q(A) 2 +ζ3Q(A) 2 +β3Q(A) 0.5 -H3λ B Q(B1) 2 -ζ B Q(B1) 2 -β B Q(B1) 0.5 = P(A) - P(B1)

[0045] H3λ B Q(B1) 2 +ζ B Q(B1) 2 +β B Q(B1)0.5 - H3λ B Q(B2) 2 -ζ B Q(B2) 2 -β B Q(B2) 0.5 =P(B1)- P(B2)

[0046] Where H3 represents the depth sounding at the center of the selected fracturing section; λ A ζ3 represents the friction coefficient gradient along the path of the first viscosity drag-reducing water; ζ3 represents the perforation friction coefficient in the first fracturing section using the first viscosity drag-reducing water; β3 represents the tortuosity friction coefficient of the first viscosity drag-reducing water; Q(A), Q(B1), and Q(B2) represent the first, second, and third discharge rates after restarting the pump following a shutdown, respectively; P(A), P(B1), and P(B2) represent the stable pressure values ​​under the first, second, and third discharge rate conditions during the pump shutdown process, respectively; λ B To utilize the friction coefficient gradient along the path of the second viscosity drag-reducing water; ζ B β is the perforation friction coefficient when using second viscosity drag-reducing water; B The tortuous friction coefficient is the coefficient of friction when using water with the second viscosity to reduce drag.

[0047] Secondly, the present invention provides an evaluation device for friction loss along the path of variable viscosity drag-reducing water, comprising:

[0048] The data acquisition module is used to acquire the discharge rate, friction-perforation friction and tortuous friction of the first viscosity drag-reducing water at the pump stop time in each fracturing section, and to acquire the data of the discharge rate reduction test based on the first viscosity drag-reducing water and the second viscosity drag-reducing water in the selected fracturing section.

[0049] The coefficient acquisition module is used to acquire the mid-depth of each fracturing section. Based on the mid-depth of each fracturing section and the discharge rate, friction-perforation friction and tortuosity friction of the first viscosity drag-reducing water at the pump stop time in each fracturing section, the friction coefficient gradient of the first viscosity drag-reducing water and the perforation friction coefficient and tortuosity friction coefficient of the first viscosity drag-reducing water in each fracturing section.

[0050] The friction coefficient evaluation module is used to calculate the friction coefficient gradient of the second viscosity drag-reducing water based on the data from the reduced discharge test, the friction coefficient gradient of the first viscosity drag-reducing water, and the perforation friction coefficient and tortuosity friction coefficient of the first viscosity drag-reducing water in the selected fracturing section, so as to complete the evaluation of the friction coefficient of the variable viscosity drag-reducing water.

[0051] Thirdly, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the method of any one of the first aspects.

[0052] Fourthly, the present invention provides an electronic device including a processor and a memory, wherein a computer program is stored in the memory, and the processor executes the computer program to implement the method of any one of the first aspects.

[0053] The technical solution of this invention obtains the discharge rate, friction-perforation friction, and tortuous friction of the first viscosity drag-reducing water at the pump shutdown time in each fracturing section, and obtains data from a discharge rate reduction test based on the first viscosity drag-reducing water and the second viscosity drag-reducing water in a selected fracturing section; obtains the mid-depth sounding of each fracturing section; and calculates the friction coefficient gradient of the first viscosity drag-reducing water, as well as the perforation friction coefficient and tortuous friction coefficient of the first viscosity drag-reducing water in each fracturing section based on the mid-depth sounding of each fracturing section and the discharge rate, friction-perforation friction, and tortuous friction of the first viscosity drag-reducing water at the pump shutdown time in each fracturing section; and calculates the friction coefficient gradient of the second viscosity drag-reducing water based on the discharge rate reduction test data, the friction coefficient gradient of the first viscosity drag-reducing water, and the perforation friction coefficient and tortuous friction coefficient of the first viscosity drag-reducing water in the selected fracturing section, thereby completing the evaluation of the friction coefficient of the variable viscosity drag-reducing water. Attached Figure Description

[0054] The invention will now be described in more detail with reference to embodiments and the accompanying drawings:

[0055] Figure 1 A schematic flowchart illustrating a method for evaluating friction loss along the flow path of drag-reducing water, provided in an embodiment of the present invention.

[0056] Figure 2 This is a schematic diagram of pump stop pressure data in seconds, provided as an embodiment of the present invention.

[0057] Figure 3 A schematic diagram of a double logarithmic pressure difference curve and a double logarithmic pressure difference derivative curve provided in an embodiment of the present invention;

[0058] Figure 4 This is a schematic diagram of a friction-reducing water friction evaluation device provided in an embodiment of the present invention.

[0059] In the accompanying drawings, the same parts are referred to by the same reference numerals, and the drawings are not drawn to scale. Detailed Implementation

[0060] To enable those skilled in the art to better understand the present invention and to fully understand and implement the process of how the present invention uses technical means to solve technical problems and achieve corresponding technical effects, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. The embodiments of the present invention and the various features therein can be combined with each other without conflict, and the resulting technical solutions are all within the protection scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0061] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0062] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0063] Currently, unconventional oil and gas resources such as shale oil and gas and tight oil and gas are developed using large-scale hydraulic fracturing, primarily employing a volumetric fracturing process of "low-viscosity, drag-reducing water + high-volume fracturing," which has enabled the efficient development of tight oil and gas resources shallower than 3500m. With the continuous deepening of exploration and development, the development of difficult-to-access oil and gas reserves in deep reservoirs exceeding 4000m is accelerating. However, due to the deep burial depth, high stress, and high construction pressure of deep oil and gas reservoirs, this presents significant challenges to surface fracturing equipment. Simultaneously, the high formation stress and narrow fracture width of deep reservoirs make proppant addition difficult, placing extremely high demands on the proppant-carrying capacity of the fracturing fluid. Furthermore, the high closure stress of deep reservoirs requires higher fracture conductivity than shallower reservoirs, necessitating increased proppant addition intensity and enhanced fracture effectiveness.

[0064] Since low-viscosity drag-reducing water cannot meet the requirements for high proppant carrying capacity, it is necessary to introduce additional medium-viscosity and high-viscosity fracturing fluid systems to compensate for the poor proppant carrying capacity of low-viscosity drag-reducing water. That is, by using different types of fracturing fluid (low-viscosity drag-reducing water, medium-viscosity linear adhesive, and high-viscosity adhesive), the needs for fracture creation and proppant carrying at different stages are met. Low-viscosity drag-reducing water creates fractures and increases fracture complexity, while medium-viscosity linear adhesive and high-viscosity adhesive carry high proppant ratios, improving fracture support and preventing rapid fracture closure under high pressure. However, in field fracturing, the formulations and preparation processes of various fracturing fluid types differ, resulting in complex fracturing fluid mixing and injection procedures. This not only requires more surface equipment but also significantly reduces fracturing efficiency, increases operational difficulty, and raises fracturing costs.

[0065] In recent years, the research and development and promotion of integrated variable viscosity drag-reducing water (integrated variable viscosity slick water) have greatly alleviated the above-mentioned technical problems.

[0066] By adding different concentrations of variable viscosity drag-reducing agents to an integrated viscosity-modifying and drag-reducing water system, drag-reducing water of varying viscosities can be obtained. This allows for real-time online mixing of fracturing fluid viscosity during fracturing operations, making the process convenient and quick. Since the frictional resistance of fracturing fluids with different viscosities varies significantly, especially the viscosity of the integrated viscosity-modifying and drag-reducing water varies considerably throughout the fracturing process depending on the concentration of the added variable viscosity drag-reducing agent, accurate assessment of the frictional resistance of the integrated viscosity-modifying and drag-reducing water at different concentrations of the variable viscosity drag-reducing agent is crucial for predicting construction risks and improving the accuracy of fracturing design parameters. Determining the frictional resistance of the integrated viscosity-modifying and drag-reducing water at different concentrations is extremely important for clarifying the optimal design space for fracturing, the limit of proppant carrying capacity at different viscosities, judging the pressure-bearing limit of surface construction equipment, and predicting construction risks.

[0067] In some fracturing design schemes, the methods for obtaining the friction resistance along the tubing string in horizontal well fracturing mainly include the following categories:

[0068] The first category involves calculating the friction loss of the tubing string using empirical estimation methods. This type of method is commonly used in field fracturing optimization design; however, it is limited by the experience of technicians and often cannot accurately predict the actual friction loss along the tubing. Especially given the current variety of fracturing fluids and the different fracturing fluid systems used in different oilfields and blocks, empirical estimation methods cannot be widely adopted.

[0069] The second category involves calculating the friction loss of a horizontal well fracturing string based on rheology and hydraulics. However, this type of method cannot currently be applied in the field because it requires input parameters such as fracturing fluid rheological parameters and wellbore roughness coefficients. The accuracy of these input parameters directly affects the calculation results; however, most of these parameters are not directly measurable. Therefore, this type of method mainly relies on assumed parameters to predict the friction loss of the fracturing string, and the predicted results often differ significantly from field conditions.

[0070] The third type involves measuring parameters through indoor experiments and then calculating and extrapolating them to the field. However, the biggest drawback of this method is that the experimental scale and the field scale cannot be kept consistent, which often leads to a significant difference between the experimental results and the field conditions.

[0071] The fourth type involves calculations based on parameters acquired from sensors. This involves directly monitoring the bottom-hole pressure by inserting pressure gauges downhole. However, this method is expensive and involves complex procedures, thus limiting its widespread application.

[0072] In summary, the above-mentioned technical solutions suffer from several problems, including difficulty in promotion and application, significant errors, high costs, and / or complex procedures. There is an urgent need in this field for a simple, economical, and rapid evaluation method to conduct on-site evaluation of the frictional resistance along the path of integrated variable viscosity drag-reducing water.

[0073] This invention utilizes actual fracturing data from fracturing operations, such as the discharge rate of first viscosity drag-reducing water at the pump stop time in each fracturing section, data obtained from selected fracturing sections based on the first viscosity drag-reducing water and second viscosity drag-reducing water for reduced discharge tests, and depth measurements in the middle of each fracturing section, to quantitatively evaluate the frictional resistance along the path of integrated variable viscosity drag-reducing water at different addition concentrations of first viscosity drag-reducing water and second viscosity drag-reducing water.

[0074] Example 1

[0075] Figure 1 This is a schematic flowchart illustrating a method for evaluating friction loss along the path of drag-reducing water, provided in an embodiment of the present invention. Figure 1 As shown, a method for evaluating frictional resistance along the path of variable viscosity and drag-reducing water includes steps S100 to S300.

[0076] Step S100: Obtain the discharge rate, friction-perforation friction, and tortuous friction of the first viscosity drag-reducing water at the pump stop time in each fracturing section, and obtain the data of the discharge rate reduction test based on the first viscosity drag-reducing water and the second viscosity drag-reducing water in the selected fracturing section.

[0077] When conducting a quantitative evaluation of frictional resistance along the flow path of variable viscosity drag-reducing water, construction operations and data collection are carried out first to obtain the discharge rate, frictional resistance along the flow path and perforation resistance, and tortuous friction of the first viscosity drag-reducing water at the pump stop time in each fracturing section. Data on the discharge rate reduction test based on the first viscosity drag-reducing water and the second viscosity drag-reducing water are then obtained in the selected fracturing section.

[0078] In some cases, the construction operation and data collection process is as follows:

[0079] In the segmented fracturing operation of the entire horizontal well, the first viscosity integrated viscosity-modifying drag-reducing water (with a fixed additive concentration), i.e., the first viscosity drag-reducing water, is selected as the main displacement fluid type after the proppant-carrying fluid is used. After the fracturing operation of each segment is completed, the pump is stopped and the pressure drop is measured. The pressure drop measurement time is not less than a set time, for example, the set time can be 2 minutes, and the second point data of pump shutdown is recorded. Figure 2 As shown.

[0080] To obtain additional friction along the path of an integrated viscosity-modifying drag-reducing water (second viscosity drag-reducing water) with varying additive concentration, any fracturing section can be selected within the entire horizontal well fracturing process. After the first viscosity drag-reducing water has replaced the fracturing fluid, the pump is stopped for a set duration (e.g., 2 minutes). The stop time data is recorded. Then, the second viscosity drag-reducing water (obtained by changing the additive concentration) is used as the replacement fluid, and fracturing fluid injection is restarted. After pumping one wellbore volume of fluid, a reduction test is conducted: the flow rate is reduced N times, and the stable surface construction pressure change data is obtained at the second point after each reduction. The corresponding flow rate data is recorded. In some cases, N=3.

[0081] Step S200: Obtain the mid-depth of each fracturing section. Based on the mid-depth of each fracturing section and the discharge rate, friction-perforation friction and tortuosity friction of the first viscosity drag-reducing water at the pump stop time in each fracturing section, calculate the friction coefficient gradient of the first viscosity drag-reducing water and the perforation friction coefficient and tortuosity friction coefficient of the first viscosity drag-reducing water in each fracturing section.

[0082] Step S300: Based on the data from the reduced discharge test, the friction coefficient gradient of the first viscosity drag-reducing water along the friction, and the perforation friction coefficient and tortuosity friction coefficient of the first viscosity drag-reducing water in the selected fracturing section, calculate the friction coefficient gradient of the second viscosity drag-reducing water along the friction to complete the evaluation of the friction of the variable viscosity drag-reducing water.

[0083] This embodiment obtains the discharge rate, friction-perforation friction, and tortuosity friction of the first viscosity drag-reducing water at the pump shutdown time in each fracturing section, and acquires data on the discharge rate reduction test based on the first viscosity drag-reducing water and the second viscosity drag-reducing water in selected fracturing sections; it also obtains the mid-depth sounding of each fracturing section, and calculates the friction coefficient gradient of the first viscosity drag-reducing water and the first viscosity drag-reducing water at the pump shutdown time in each fracturing section based on the mid-depth sounding of each fracturing section and the first viscosity drag-reducing water at the pump shutdown time, friction-perforation friction, and tortuosity friction in each fracturing section. The perforation friction coefficient and tortuosity friction coefficient of the first viscosity drag-reducing water in each fracturing section were calculated. Based on the data from the reduced discharge test, the friction coefficient gradient of the first viscosity drag-reducing water, and the perforation friction coefficient and tortuosity friction coefficient of the first viscosity drag-reducing water in the selected fracturing section, the friction coefficient gradient of the second viscosity drag-reducing water was calculated to complete the evaluation of the friction of the variable viscosity drag-reducing water. This provides a simple post-fracturing field evaluation method to evaluate the friction of the integrated variable viscosity drag-reducing water in horizontal well segmented and clustered fracturing.

[0084] The method provided in this embodiment is a simple on-site evaluation method after fracturing, used to evaluate the frictional resistance of integrated viscosity-modifying and drag-reducing water in horizontal well segmented and clustered fracturing. Using actual pressure data at the fracturing site, the frictional resistance of integrated viscosity-modifying and drag-reducing water with different additive concentrations is quantitatively evaluated. Under the condition of not affecting pressure construction, the frictional resistance of integrated viscosity-modifying and drag-reducing water with different drag-reducing agent additive concentrations and different viscosities is quickly, easily and in real time evaluated on-site using the second-point data of pump shutdown pressure and corresponding pump shutdown process.

[0085] Example 2

[0086] Based on the above embodiments, step S100 obtains the discharge rate, friction-perforation friction and tortuous friction of the first viscosity drag-reducing water at the pump stop time in each fracturing section, including steps S101 to S103.

[0087] Step S101: After the fracturing operation of each fracturing section is completed, stop the pump, measure the pressure drop, and record the second data of pump shutdown.

[0088] Step S102: Plot the double logarithmic pressure difference derivative curve of the fracturing section based on the pump stop time data.

[0089] Step S103: Calculate the frictional resistance along the fracturing section and the tortuous frictional resistance based on the pressure corresponding to the pressure at the time of pump shutdown and the pressure corresponding to the first hump of the double logarithmic pressure difference derivative curve.

[0090] In some implementations, step S103 calculates the frictional resistance along the fracturing section and the tortuous frictional resistance based on the pressure corresponding to the pressure at the time of pump shutdown and the pressure corresponding to the first hump of the double logarithmic pressure difference derivative curve, including steps S1031 to S1032.

[0091] Step S1031: Calculate the pressure at the moment the pump stops and the pressure at the moment the first peak of the double logarithmic pressure difference derivative curve appears, to obtain the frictional resistance along the fracturing section.

[0092] Step S1032: Calculate the difference between the pressure corresponding to the first peak of the double logarithmic pressure difference derivative curve and the pressure corresponding to the end of the first peak of the double logarithmic pressure difference derivative curve to obtain the tortuous friction of the fracturing section.

[0093] In this embodiment, after the fracturing operation of each fracturing segment is completed, the pump is stopped and the pressure drop is measured. The data at the second point of pump stoppage is recorded. Then, based on the data at the second point of pump stoppage, a double logarithmic pressure difference derivative curve of the fracturing segment is plotted. This determines the pressure corresponding to the pump stoppage time and the pressure corresponding to the first peak of the double logarithmic pressure difference derivative curve, thereby achieving the technical effect of obtaining the friction-perforation friction and tortuous friction of the fracturing segment.

[0094] In this embodiment, the appearance and end of the first hump of the double logarithmic pressure difference derivative curve are taken as key points. The pressure corresponding to the appearance of the first hump and the pressure corresponding to the end of the first hump of the double logarithmic pressure difference derivative curve are obtained respectively. Then, the difference between the pressure corresponding to the pump stop time and the pressure corresponding to the appearance of the first hump of the double logarithmic pressure difference derivative curve is calculated to obtain the friction-perforation friction of the fracturing section. The difference between the pressure corresponding to the appearance of the first hump and the pressure corresponding to the end of the first hump of the double logarithmic pressure difference derivative curve is calculated to obtain the tortuous friction of the fracturing section. Thus, the friction-perforation friction and friction-perforation friction of each fracturing section are obtained based on the pump stop time data.

[0095] Example 3

[0096] Based on the above embodiments, step S200 calculates the friction coefficient gradient of the first viscosity drag-reducing water and the perforation friction coefficient and tortuous friction coefficient of the first viscosity drag-reducing water in each fracturing section based on the mid-depth sounding of each fracturing section and the pump stop flow rate, friction-perforation friction and tortuous friction of the first viscosity drag-reducing water in each fracturing section, including steps S201 to S202.

[0097] Step S201: Calculate the friction coefficient and tortuous friction coefficient of the first viscosity drag-reducing water in each fracturing section based on the pump stop time discharge rate, friction-perforation friction, and tortuous friction of the first viscosity drag-reducing water in each fracturing section.

[0098] Step S202: Based on the mid-depth sounding of each fracturing section and the friction coefficient along the perforation, the friction coefficient gradient of the first viscosity drag-reducing water is obtained.

[0099] In some embodiments of this example, step S201, which calculates the friction coefficient and tortuous friction coefficient of the first viscosity drag-reducing water in each fracturing section based on the pump stop time discharge rate, friction-perforation friction, and tortuous friction of the first viscosity drag-reducing water in each fracturing section, includes steps S2011 and S2012.

[0100] Step S2011: Calculate the friction coefficient along the perforation path of the first viscosity drag-reducing water in each fracturing section using the following expression:

[0101] α= P well-perf / Q 2

[0102] Where α is the friction coefficient along the perforation path, and P well-perf Let Q be the frictional resistance along the perforation path, and Q be the discharge rate at the moment the pump stops.

[0103] Step S2012: Calculate the tortuous friction coefficient of the first viscosity drag-reducing water in each fracturing section using the following expression:

[0104] β=P tort / Q 0.5

[0105] Where β is the tortuosity friction coefficient, P tort For tortuous friction, Q is the discharge rate at the moment the pump stops.

[0106] In some embodiments of this example, step S202 obtains the friction coefficient gradient of the first viscosity drag-reducing water based on the mid-depth sounding of each fracturing section and the friction coefficient along the perforation, including steps S2021 and S2022.

[0107] Step S2021: Calculate the friction coefficient gradient along the frictional path of the first viscosity drag-reducing water in each fracturing section using the following expression:

[0108] λ i =α i / H i

[0109] Where i is the fracturing segment number, 1≤i≤n, and n is the total number of fracturing segments; α i H is the friction coefficient along the perforation path of the i-th fracturing section; i The depth is measured at the middle of the i-th fracturing segment.

[0110] Step S2022: The minimum value of the friction coefficient gradient along the perforation in each fracturing section is taken as the friction coefficient gradient along the first viscosity drag-reducing water.

[0111] In some embodiments of this example, based on the mid-depth of each fracturing section and the discharge rate of the first viscosity drag-reducing water at the pump stop time in each fracturing section, the friction-perforation friction and the tortuous friction, the friction coefficient gradient of the first viscosity drag-reducing water and the perforation friction coefficient and the tortuous friction coefficient of the first viscosity drag-reducing water in each fracturing section are calculated, and step S203 is also included.

[0112] Step S203: Based on the friction coefficient gradient along the path of the first viscosity drag-reducing water and the mid-depth measurement of each fracturing section, the perforation friction coefficient of each fracturing section is obtained.

[0113] In this embodiment, the friction coefficient and tortuosity friction coefficient of the first viscosity drag-reducing water in each fracturing section are calculated based on the pump stop rate, friction-perforation friction, and tortuosity friction at each fracturing section. The friction-perforation friction coefficient gradient of the first viscosity drag-reducing water in each fracturing section is obtained based on the mid-depth sounding and friction-perforation friction coefficient of each fracturing section. The minimum value of the friction-perforation friction coefficient gradient of each fracturing section is taken as the friction coefficient gradient of the first viscosity drag-reducing water, thereby determining the friction coefficient gradient of the first viscosity drag-reducing water.

[0114] Example 4

[0115] Based on the above embodiments, the selected fracturing segment is any one of the fracturing segments selected from all the fracturing segments;

[0116] In step S100, data on the reduction of discharge rate based on first viscosity drag-reducing water and second viscosity drag-reducing water are obtained in the selected fracturing section, including steps S401 to S404.

[0117] Step S401: After selecting the fracturing section and recording the pump stop time data, restart the pump.

[0118] Step S402: Pump the first viscosity drag-reducing water at the first displacement Q(A) and obtain the first pressure P(A) after the pressure stabilizes.

[0119] Step S403: Pump the second viscosity drag-reducing water at the second displacement Q(B1). After pumping a wellbore volume of liquid, record the stable second pressure P(B1).

[0120] In step S404, the second viscosity drag-reducing water is pumped at a third displacement Q(B2) that is less than the second displacement to conduct a displacement reduction test and obtain a stable third pressure P(B2).

[0121] In some embodiments of this example, step S300, based on data from the reduction-rate test, the friction coefficient gradient of the first viscosity drag-reducing water, and the perforation friction coefficient and tortuosity friction coefficient of the first viscosity drag-reducing water in the selected fracturing section, calculates the friction coefficient gradient of the second viscosity drag-reducing water, including:

[0122] The friction coefficient gradient along the path of the second viscosity drag-reducing water is calculated using the following expression:

[0123] H3λ A Q(A) 2 +ζ3Q(A) 2 +β3Q(A) 0.5 -H3λ B Q(B1) 2 -ζ B Q(B1) 2 -β B Q(B1) 0.5 = P(A) - P(B1)

[0124] H3λ B Q(B1) 2 +ζ B Q(B1) 2 +β B Q(B1) 0.5 - H3λ B Q(B2) 2 -ζ B Q(B2) 2 -β B Q(B2) 0.5 =P(B1)- P(B2)

[0125] Where H3 represents the depth sounding at the center of the selected fracturing section; λ A ζ3 represents the friction coefficient gradient along the path of the first viscosity drag-reducing water; ζ3 represents the perforation friction coefficient in the first fracturing section using the first viscosity drag-reducing water; β3 represents the tortuosity friction coefficient of the first viscosity drag-reducing water; Q(A), Q(B1), and Q(B2) represent the first, second, and third discharge rates after restarting the pump following a shutdown, respectively; P(A), P(B1), and P(B2) represent the stable pressure values ​​under the first, second, and third discharge rate conditions during the pump shutdown process, respectively; λ B To utilize the friction coefficient gradient along the path of the second viscosity drag-reducing water; ζ B β is the perforation friction coefficient when using second viscosity drag-reducing water; B The tortuous friction coefficient is the coefficient of friction when using water with the second viscosity to reduce drag.

[0126] This embodiment allows for a rapid, simple, and real-time on-site evaluation of the frictional resistance of integrated variable viscosity drag-reducing water with different drag-reducing agent concentrations and viscosities, using pump shutdown pressure data and appropriate pump shutdown procedures, without affecting fracturing operations.

[0127] Example 5

[0128] In this embodiment, a deep shale gas horizontal well in the Sichuan Basin is used as an example to illustrate the specific implementation of the present invention.

[0129] The horizontal well has a depth of 5900.0m and a vertical depth of 4040.0m, with a horizontal section length of 1500m and a total of 28 fracturing sections. This well utilizes an integrated viscosity-modifying and drag-reducing water system. By adding different concentrations of the integrated viscosity-modifying and drag-reducing agent, different viscosities of the integrated viscosity-modifying and drag-reducing water are obtained, thus achieving real-time online mixing of fracturing fluid viscosity during fracturing operations, making operation convenient and quick. Specifically, when the integrated viscosity-modifying and drag-reducing agent concentration is 0.1%, it is a low-viscosity drag-reducing water (equivalent to the first viscosity drag-reducing water), mainly used for fracture creation and forming complex fractures; when the integrated viscosity-modifying and drag-reducing agent concentration is 0.35%, it is a high-viscosity drag-reducing water (equivalent to the second viscosity drag-reducing water), mainly used for proppant carrying when the proppant ratio is higher than 10%, reducing the risk of proppant addition in high proppant ratio sections.

[0130] Collect and organize the second-point data of the construction pressure of each section of the well, and obtain the frictional resistance along the way of the integrated viscosity-changing and drag-reducing water with different concentrations through the following steps:

[0131] Step (1): Throughout the horizontal well fracturing operation, select a viscosity-adjusting drag-reducing water (e.g., low-viscosity drag-reducing water with a concentration of 0.1% of the aforementioned integrated viscosity-adjusting drag-reducing agent), i.e., the first viscosity drag-reducing water, as the main displacement fluid type after the sand-carrying fluid is used. After the fracturing operation is completed, stop the pump and measure the pressure drop for at least 2 minutes, recording the second data at the pump stop point. (See [reference needed]). Figure 2 The diagram shown illustrates the second-point data of the pump stop pressure. Figure 2 In this text, A-viscosity drag-reducing water represents the first viscosity drag-reducing water, and B-viscosity drag-reducing water represents the second viscosity drag-reducing water.

[0132] Step (2): Taking the first fracturing stage as an example, analyze the data at the moment the pump was shut down during fracturing operations, and determine the pressure P(t) at the moment the pump was shut down based on the data. p =0) is 82.11 MPa, and the discharge Q at the moment of pump shutdown is 4.03 m³. 3 / min.

[0133] Step (3): Taking the pump stop time as the origin (t) p =0), based on the pressure P(t) after the pump stops p ) and pump stop time tp For data, to plot the double logarithmic pressure curve and the double logarithmic pressure difference derivative curve, please refer to [reference needed]. Figure 3 The diagram shows the double logarithmic pressure difference curve and the double logarithmic pressure difference derivative curve.

[0134] Step (4): On the double logarithmic pressure difference derivative curve, observe the moment t when the first "hump" appears. p1 (Generally occurring within a few seconds after pump shutdown), the first "hump" peak appears 10 seconds after pump shutdown (i.e. Figure 3 t p1 (Time), record the corresponding pressure P(t) p1 The pressure is 73.71 MPa, where t p1 The time is the frictional resistance P along the perforation path. well-perf At the time of disappearance, according to P(t) p1 ) and P(t p =0) The difference is the frictional resistance along the perforation, which is 8.4 MPa.

[0135] Step (5): After the first "hump" peak, the double logarithmic pressure derivative curve begins to decline rapidly. Determine the time t at which the first "hump" on the double logarithmic pressure derivative curve ends. p2 (Generally occurring within tens of seconds after pump shutdown), the inflection point of the rapid decline curve after the first "hump" appears 80 seconds after pump shutdown; record the corresponding pressure value P(t). p2 The instantaneous pump stop pressure is 71.2 MPa, where t p2 The moment is the tortuous friction P tort At the moment of disappearance, the tortuous friction is P(t). p2 ) and P(t p1 The difference is 2.51 MPa.

[0136] Step (6): Calculate the frictional resistance along the perforation and the tortuous frictional resistance using expressions (1) and (2), respectively.

[0137] P well-perf = P(t p =0)- P(t p1 (1)

[0138] P tort = P(t p1 )- P(t p2 (2)

[0139] Among them, P well-perf For frictional resistance along the perforation path, P tort It is a circuitous and obstructive path.

[0140] The frictional resistance P along the first stage of fracturing was obtained. well-perf-1The tortuous friction P is 8.4 MPa. tort-1 It is 2.51 MPa.

[0141] Step (7) Repeat steps (2) to (6) to obtain the values ​​of pump stop time discharge, pump stop time pressure, friction-perforation friction, tortuous friction and instantaneous pump stop pressure for each fracturing section (e.g., fracturing sections 1 to 28). The summaries are shown in Table 1.

[0142] Table 1 Basic Data Statistics Table

[0143]

[0144] Step (8): Based on the pump stop time, discharge rate, friction-perforation friction, and tortuous friction of each fracturing section, calculate the friction-perforation friction coefficient α and tortuous friction coefficient β of each fracturing section when using first viscosity drag-reducing water using expressions (3) and (4). The calculation results are shown in Table 2.

[0145] Friction coefficient along the perforation α and tortuosity friction coefficient β:

[0146] α= P well-perf / Q 2 (3)

[0147] β=P tort / Q 0.5 (4)

[0148] Table 2. Friction coefficients along the perforation and tortuosity for each section

[0149]

[0150] Step (9): Calculate the mid-depth of each fracturing section and, based on expression (5), calculate the friction coefficient gradient λ along the perforation of each fracturing section. i See Table 3. It can be seen that the friction coefficient gradient along the path to the perforation is the smallest in the 13th fracturing stage, at 7.33728 × 10⁻⁶. -6 .

[0151] Calculate the friction coefficient gradient along the fracture path to the perforation in each fracture section when using drag-reducing water of the first viscosity, and the friction coefficient gradient λ of the i-th fracture section. i for:

[0152] λ i =α i / H i (5)

[0153] In the formula, i is the fracturing segment number; n is the total number of fracturing segments; α i H is the friction coefficient along the perforation path of the i-th fracturing section; i The depth measured at the center of the i-th fracturing segment is in meters.

[0154] Table 3 Calculation results of friction coefficient gradient along the perforation section

[0155]

[0156] Step (10): To distinguish between friction friction and perforation friction, it is assumed that the perforation friction of the fracturing section with the smallest friction friction coefficient gradient in the horizontal well (section 13 in this embodiment) is approximately 0, meaning that the friction friction of section 13 is all friction friction. Therefore, the friction friction coefficient gradient corresponding to section 13 is the friction friction coefficient gradient λ when using the first viscosity drag-reducing water. A :

[0157] λ A =minλ i (i=1,2,···,n)(6)

[0158] Then, based on the product of the mid-depth of each of the remaining fracturing sections and the friction coefficient gradient under the first viscosity drag-reducing water, the friction coefficient η of each fracturing section is obtained. i :

[0159] η i =λ A H i (7)

[0160] Furthermore, the friction coefficient α along the perforation path of each fracturing section is... i With friction coefficient η i Subtracting these values ​​yields the perforation friction coefficient ζ for each fracturing section. i .

[0161] Table 4 Calculation results of frictional resistance along the road and perforation friction for each section

[0162]

[0163] Step (11): Based on the pump stop time and discharge rate of each section, the perforation friction and friction along the flow path of each fracturing section at the pump stop time are calculated using expressions (3), (4) and Table 1, as shown in Table 5.

[0164] For example, the friction along the path and the perforation friction of each segment can be calculated using expressions (3) and (4); or the friction along the path or the perforation friction of each segment can be calculated using expressions (3) or (4), and then combined with the friction along the path and the perforation friction in Table 1 to obtain the perforation friction or friction along the path of each segment.

[0165] Table 5 Summary of frictional resistance interpretation results at each pump shutdown time

[0166]

[0167] Step (12): To obtain the frictional resistance along the flow path of integrated viscosity-modifying drag-reducing water of other viscosities (e.g., second viscosity drag-reducing water with an integrated viscosity-modifying drag-reducing agent concentration of 0.35%), the third fracturing section was selected as the selected fracturing section. After the first viscosity drag-reducing water was replaced, the pump was stopped for 2 minutes, and the pump stop time data was recorded. Then, the pump was restarted. S1: The first viscosity drag-reducing water was pumped at a displacement of Q(A). After the pressure stabilized, the stable construction pressure P(A) was obtained. S2: The fluid was changed, and the second viscosity drag-reducing water was used as the replacement fluid. Pumping was started at a displacement of Q(B1). After pumping one wellbore volume of fluid, the stable construction pressure P(B1) was recorded. S3: Then, a reduction displacement test Q(B2) was carried out to obtain the stable construction pressure P(B2) after the reduction displacement, and the corresponding displacement and stable construction pressure values ​​were recorded.

[0168] Table 6. Discharge Rate for Reduced Emission Test and Stable Construction Pressure

[0169]

[0170] (13) Calculate the friction coefficient gradient λ along the path when using the second viscosity drag-reducing water. B Perforation friction coefficient ζ B and near-well friction coefficient β B ,

[0171] H3λ A Q(A) 2 +ζ3Q(A) 2 +β3Q(A) 0.5 -H3λ B Q(B1) 2 -ζ B Q(B1) 2 -β B Q(B1) 0.5 = P(A)- P(B1)(8)

[0172] H3λ B Q(B1) 2 +ζ B Q(B1) 2 +β B Q(B1) 0.5 - H3λ B Q(B2) 2 -ζ B Q(B2) 2 -β B Q(B2) 0.5 =P(B1)- P(B2)(9)

[0173] Where H3 is the mid-depth sounding of the third fracturing section, in meters; λA To utilize the friction coefficient gradient along the path of the first viscosity drag-reducing water, λ A =7.33728×10 -6 ζ3 is the perforation friction coefficient of the third fracturing section when using the first viscosity drag-reducing water, and ζ3 is calculated from step (10) above; β3 is the tortuous friction coefficient of the third fracturing section when using the first viscosity drag-reducing water, and β3 is calculated from steps (2) and (4) above; Q(A), Q(B1), and Q(B2) are the two discharge rates after restarting the pump after stopping, in m³. 3 / min; P(A), P(B1), and P(B2) are the stable construction pressure values ​​under the discharge conditions of Q(A), Q(B1), and Q(B2) during the pump shutdown process, respectively, in MPa; λ B To utilize the friction coefficient gradient along the path of the second viscosity drag-reducing water; ζ B β is the perforation friction coefficient when using second viscosity drag-reducing water; B The tortuous friction coefficient is the coefficient of friction when using water with the second viscosity to reduce drag.

[0174] Since the perforation friction coefficient is independent of the fracturing fluid type, then

[0175] ζ3=ζ B (10)

[0176] Where ζ3 is the friction coefficient of the third perforation section, obtained from step (10) above, and is 0.00932. Combining (8) and (10), the friction coefficient gradient λ of the third section when using the second viscosity drag-reducing water can be obtained. B and near-well friction coefficient β B Solving for λ, we get λ. B =3.475×10 -5 ,β B =0.3448.

[0177] Example 6

[0178] Figure 4 This is a schematic diagram of a friction-reducing water friction evaluation device provided in an embodiment of the present invention. Figure 4 As shown, based on the above embodiments, this embodiment provides an evaluation device for friction loss of variable viscosity drag-reducing water, comprising:

[0179] The data acquisition module 100 is used to acquire the discharge rate, friction-perforation friction and tortuous friction of the first viscosity drag-reducing water at the pump stop time in each fracturing section, and to acquire the data of the discharge rate reduction test based on the first viscosity drag-reducing water and the second viscosity drag-reducing water in the selected fracturing section.

[0180] The coefficient acquisition module 200 is used to acquire the mid-depth of each fracturing section. Based on the mid-depth of each fracturing section and the discharge rate, friction-perforation friction and tortuosity friction of the first viscosity drag-reducing water at the pump stop time in each fracturing section, the friction coefficient gradient of the first viscosity drag-reducing water and the perforation friction coefficient and tortuosity friction coefficient of the first viscosity drag-reducing water in each fracturing section.

[0181] The friction coefficient evaluation module 300 is used to calculate the friction coefficient gradient of the second viscosity drag-reducing water based on the data from the reduced discharge test, the friction coefficient gradient of the first viscosity drag-reducing water, and the perforation friction coefficient and tortuosity friction coefficient of the first viscosity drag-reducing water in the selected fracturing section, so as to complete the evaluation of the friction coefficient of the variable viscosity drag-reducing water.

[0182] The friction loss evaluation device for variable viscosity drag-reducing water is used to perform the friction loss evaluation method for drag-reducing water in the above embodiments. A detailed description of the friction loss evaluation method for drag-reducing water can be found in the detailed description of the above embodiments, and will not be repeated in this embodiment.

[0183] Example 7

[0184] Based on the above embodiments, this embodiment also provides a computer-readable storage medium, such as flash memory, hard disk, multimedia card, card-type memory (e.g., SD or DX memory), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic memory, disk, optical disk, server, etc., which stores a computer program. When the computer program is executed, it can implement the frictional resistance evaluation method for drag-reducing water in the above embodiments.

[0185] Example 8

[0186] Based on the above embodiments, this application provides an electronic device, which may be a mobile phone, computer, or tablet computer, or a device for optimizing water resistance, including a memory and a processor. The memory stores a calculator program, which, when executed by the processor, implements the friction loss evaluation method for drag-reducing water as described in the above embodiments. It is understood that the electronic device may also include multimedia components, input / output (I / O) interfaces, and communication components.

[0187] The processor is used to execute all or part of the steps in the friction loss evaluation method for drag-reducing water as described in the above embodiments. The memory is used to store various types of data, which may include, for example, instructions for any application or method in the electronic device, as well as application-related data.

[0188] The processor can be implemented as an Application Specific Integrated Circuit (ASIC), Digital Signal Processor (DSP), Digital Signal Processing Device (DSPD), Programmable Logic Device (PLD), Field Programmable Gate Array (FPGA), controller, microcontroller, microprocessor, or other electronic components, and is used to perform all or part of the steps in the friction loss evaluation method for drag-reducing water in the above embodiments.

[0189] Memory can be implemented from any type of volatile or non-volatile storage 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 storage, flash memory, magnetic disk or optical disk.

[0190] In the embodiments provided by this invention, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0191] It should be noted that, in this invention, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element limited by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0192] While the embodiments disclosed in this invention are as described above, the above content is merely for the purpose of facilitating understanding of this invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and changes in form and detail of the implementation without departing from the spirit and scope disclosed in this invention; however, the scope of patent protection of this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A method for evaluating frictional resistance along the path of variable viscosity and drag-reducing water, characterized in that, include: Obtain the discharge rate, friction-perforation friction, and tortuous friction of the first viscosity drag-reducing water at the pump shutdown time in each fracturing stage, including: After the fracturing operation of each fracturing section is completed, the pump is stopped and the pressure drop is measured, and the data at the second point of pump shutdown is recorded. Based on the pump shutdown time data, a double logarithmic pressure difference derivative curve of the fracturing section was plotted. The frictional resistance along the fracturing section and the tortuous frictional resistance are calculated based on the pressure corresponding to the pressure at the moment of pump shutdown and the pressure corresponding to the first hump of the double logarithmic pressure difference derivative curve. And data on the reduction of discharge rate based on first viscosity drag-reducing water and second viscosity drag-reducing water were obtained in the selected fracturing section, including: After selecting the fracturing section and recording the pump stop time data, restart the pump; Pump the first viscosity drag-reducing water at the first displacement Q(A) and obtain the first pressure P(A) after the pressure stabilizes. Pump the second viscosity drag-reducing water at the second displacement Q(B1). After pumping one wellbore volume of liquid, record the stable second pressure P(B1). A second viscosity drag-reducing water was pumped at a third displacement Q(B2), which is less than the second displacement, to conduct a displacement reduction test and obtain a stable third pressure P(B2). Wherein, the selected fracturing segment is any fracturing segment selected from all fracturing segments; Obtain the mid-depth of each fracturing section. Based on the mid-depth of each fracturing section and the discharge rate, friction-perforation friction and tortuosity friction of the first viscosity drag-reducing water at the pump stop time in each fracturing section, calculate the friction coefficient gradient of the first viscosity drag-reducing water and the perforation friction coefficient and tortuosity friction coefficient of the first viscosity drag-reducing water in each fracturing section. Based on the data from the reduced discharge rate test, the friction coefficient gradient of the first viscosity drag-reducing water, and the perforation friction coefficient and tortuosity friction coefficient of the first viscosity drag-reducing water in the selected fracturing section, the friction coefficient gradient of the second viscosity drag-reducing water is calculated to complete the evaluation of the friction coefficient of the variable viscosity drag-reducing water, including: The friction coefficient gradient along the path of the second viscosity drag-reducing water is calculated using the following expression: H3λ A Q(A) 2 +ζ3Q(A) 2 +β3Q(A) 0.5 -H3λ B Q(B1) 2 -g B Q(B1) 2 -b B Q(B1) 0.5 = P(A)- P(B1) H3λ B Q(B1) 2 +ζ B Q(B1) 2 +β B Q(B1) 0.5 - H3λ B Q(B2) 2 -ζ B Q(B2) 2 -β B Q(B2) 0.5 =P(B1)- P(B2) Where H3 is the depth sounding at the middle of the selected fracturing section; λ A ζ3 represents the friction coefficient gradient along the path of the first viscosity drag-reducing water; ζ3 represents the perforation friction coefficient in the first fracturing section using the first viscosity drag-reducing water; β3 represents the tortuosity friction coefficient of the first viscosity drag-reducing water; λ B To utilize the friction coefficient gradient along the path of the second viscosity drag-reducing water; ζ B β is the perforation friction coefficient when using second viscosity drag-reducing water; B The tortuous friction coefficient is the coefficient of friction when using water with the second viscosity to reduce drag.

2. The method according to claim 1, characterized in that, The calculation of the friction-perforation friction and tortuous friction of the fracturing section based on the pressure corresponding to the pressure at the time of pump shutdown and the pressure corresponding to the first hump of the double logarithmic pressure difference derivative curve includes: The pressure at the moment of pump shutdown is calculated as the difference between the pressure at which the first peak of the double logarithmic pressure difference derivative curve appears, and the frictional resistance along the fracturing section is obtained. The tortuous friction of the fracturing section is obtained by calculating the difference between the pressure corresponding to the appearance of the first hump of the double logarithmic pressure difference derivative curve and the pressure corresponding to the end of the first hump of the double logarithmic pressure difference derivative curve.

3. The method according to claim 1, characterized in that, The calculation of the friction coefficient gradient of the first viscosity drag-reducing water and the perforation and tortuosity friction coefficients of the first viscosity drag-reducing water in each fracturing section, based on the mid-depth sounding of each fracturing section and the pump stoppage rate, friction-perforation friction, and tortuosity friction of the first viscosity drag-reducing water in each fracturing section, includes: Based on the discharge rate, friction-perforation friction, and tortuous friction of the first viscosity drag-reducing water at the pump stop time in each fracturing section, calculate the friction-perforation friction coefficient and tortuous friction coefficient of the first viscosity drag-reducing water in each fracturing section. The friction coefficient gradient of the first viscosity drag-reducing water is obtained based on the mid-depth sounding of each fracturing section and the friction coefficient along the perforation.

4. The method according to claim 3, characterized in that, The calculation of the friction coefficient gradient of the first viscosity drag-reducing water and the perforation friction coefficient and tortuosity friction coefficient of the first viscosity drag-reducing water in each fracturing section based on the mid-depth sounding of each fracturing section and the pump stop flow rate, friction-perforation friction, and tortuosity friction of the first viscosity drag-reducing water in each fracturing section also includes: The perforation friction coefficient of each fracturing section is obtained based on the friction coefficient gradient along the path of the first viscosity drag-reducing water and the mid-depth measurement of each fracturing section.

5. The method according to claim 3, characterized in that, The calculation of the friction coefficient and tortuosity coefficient of the first viscosity drag-reducing water in each fracturing stage based on the pump stop rate, friction-perforation friction, and tortuosity friction at each fracturing stage includes: The friction coefficient along the perforation of the first viscosity drag-reducing water in each fracturing stage is calculated using the following expression: α= P well-perf / Q 2 Where α is the friction coefficient along the perforation path, and P well-perf Let Q be the frictional resistance along the perforation path, and Q be the discharge rate at the moment the pump stops.

6. The method according to claim 3, characterized in that, The calculation of the friction coefficient and tortuosity coefficient of the first viscosity drag-reducing water in each fracturing stage based on the pump stop rate, friction-perforation friction, and tortuosity friction at each fracturing stage includes: The tortuous friction coefficient of the first viscosity drag-reducing water in each fracturing stage is calculated using the following expression: β=P tort / Q 0.5 Where β is the tortuosity friction coefficient, P tort For tortuous friction, Q is the discharge rate at the moment the pump stops.

7. The method according to claim 3, characterized in that, The method of obtaining the friction coefficient gradient of the first viscosity-reducing water based on the mid-depth sounding and friction coefficient along the perforation of each fracturing section includes: The friction coefficient gradient along the frictional path of the first viscosity drag-reducing water in each fracturing stage is calculated using the following expression: l i =a i / H i Where i is the fracturing segment number, 1≤i≤n, and n is the total number of fracturing segments; α i H is the friction coefficient along the perforation path of the i-th fracturing section; i The depth is measured at the middle of the i-th fracturing segment.

8. The method according to claim 7, characterized in that, The method of obtaining the friction coefficient gradient of the first viscosity-reducing water based on the mid-depth sounding and friction coefficient along the perforation of each fracturing section further includes: The minimum value among the friction coefficient gradients along the friction-perforation coefficient of each fracturing section is taken as the friction coefficient gradient along the friction of the first viscosity drag-reducing water.

9. An apparatus for evaluating the friction resistance of variable viscosity reduced-drag water using the method for evaluating friction resistance of variable viscosity reduced-drag water according to any one of claims 1 to 8, characterized in that, include: The data acquisition module is used to acquire the discharge rate, friction-perforation friction and tortuous friction of the first viscosity drag-reducing water at the pump stop time in each fracturing section, and to acquire the data of the discharge rate reduction test based on the first viscosity drag-reducing water and the second viscosity drag-reducing water in the selected fracturing section. The coefficient acquisition module is used to acquire the mid-depth of each fracturing section. Based on the mid-depth of each fracturing section and the discharge rate, friction-perforation friction and tortuosity friction of the first viscosity drag-reducing water at the pump stop time in each fracturing section, the friction coefficient gradient of the first viscosity drag-reducing water and the perforation friction coefficient and tortuosity friction coefficient of the first viscosity drag-reducing water in each fracturing section. The friction coefficient evaluation module is used to calculate the friction coefficient gradient of the second viscosity drag-reducing water based on the data from the reduced discharge test, the friction coefficient gradient of the first viscosity drag-reducing water, and the perforation friction coefficient and tortuosity friction coefficient of the first viscosity drag-reducing water in the selected fracturing section, so as to complete the evaluation of the friction coefficient of the variable viscosity drag-reducing water.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method of any one of claims 1 to 8.

11. An electronic device comprising a processor and a memory, characterized in that, The memory stores a computer program, and the processor executes the computer program to implement the method of any one of claims 1 to 8.

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