Full-automatic fracturing fluid powder online mixing device and mixing method

Abstract

The present invention relates to the technical field of shale oil extraction, and specifically relates to a fully automatic online mixing device and mixing method for fracturing fluid powder, including: obtaining the target mixing parameter a with the highest priority from the mixing parameter set; the mixing device performs mixing work with a, and obtains the mother liquor uniformity change sequence A and the stability of a, adjusts the attention coefficient of a according to the stability, and re-obtains the target mixing parameter b from the mixing parameter set according to the adjusted attention coefficient; uses the PID algorithm to change the mixing parameter of the mixing device from a to b, and records the mother liquor uniformity change sequence B, adjusts the attention coefficient of b according to the difference between the mother liquor uniformity change sequences A and B, and the priorities of a and b; then deletes the mixing parameter with the smallest attention coefficient in the mixing parameter set, and the mixing device performs mixing work with b. The present invention improves the mixing efficiency when mixing the mother liquor of the fracturing fluid online, and prevents the occurrence of uneven situations such as fish eyes and sticky lumps.

Description

Technical Field

[0001] The present invention relates to the technical field of shale oil extraction, and particularly to a full-automatic online mixing device and method for fracturing fluid powder. Background Art

[0002] The hydraulic fracturing technology is one of the most commonly used methods for shale oil extraction at present. This technology utilizes the principles of high-pressure water injection, rock fracturing, and oil and gas discharge, injecting fracturing fluid (water and chemical additives) into the rock fractures to form high pressure, causing the rock to fracture and further develop along the rock layer. The hydraulic fracturing technology can release shale oil from the rock pores for convenient recovery. The hydraulic fracturing technology requires the use of polymer dry powder to prepare fracturing fluid. In order to save the preparation cost of fracturing fluid, it is necessary to online prepare the powder into a large-displacement fracturing mother liquor at the fracturing site; however, when using the existing production process for online preparation of the mother liquor, there are problems such as inappropriate mixing ratios of the powder and clear water, and the inability to quickly, efficiently, and uniformly mix the powder and clear water, which in turn leads to problems such as fish eyes (water-in-powder) and sticky lumps (powder-in-water). Summary of the Invention

[0003] To solve the above problems, the present invention provides a full-automatic online mixing device and method for fracturing fluid powder.

[0004] The full-automatic online mixing device and method for fracturing fluid powder of the present invention adopt the following technical solutions:

[0005] An embodiment of the present invention provides a full-automatic online mixing device for fracturing fluid powder, which includes: a water supply tank at the fracturing site, a dry powder tank, and a blender truck. The clear water output from the water supply tank at the fracturing site forms a jet in a high powder-to-water ratio injector after passing through a booster pump; the polymer dry powder in the dry powder tank is transported to a dry powder hopper through a spiral metering feeder; the negative pressure of the jet in the high powder-to-water ratio injector lifts the polymer dry powder in the dry powder hopper into the high powder-to-water ratio injector, and the polymer dry powder and the water jet in the high powder-to-water ratio injector collide and mix to obtain the mother liquor;

[0006] The mother liquor enters the buffer tank, and the mother liquor in the buffer tank is transported to a static mixing and dilution skid. The water supply tank at the fracturing site is connected to the static mixing and dilution skid. After the mother liquor in the static mixing and dilution skid is mixed with the clear water provided by the water supply tank at the fracturing site, it is sucked into the blender truck by a suction pump of the blender truck and then mixed with sand in a mixing tank, and finally transported to a fracturing pump and pumped into the formation;

[0007] An ultrasonic sensor is installed in the buffer tank to detect the uniformity of the mother liquor in the buffer tank.

[0008] An embodiment of the present invention also provides a method for online mixing of full-automatic fracturing fluid powder. Using the above-mentioned full-automatic fracturing fluid powder online mixing device, the method includes the following steps:

[0009] The feeding speed of the dry powder hopper, the water volume output by the water supply tank at the fracturing site, and the water pressure output by the booster pump are recorded as a set of mixing parameters of the mixing device;

[0010] Obtain the mixing parameter with the highest priority from the mixing parameter set as the target mixing parameter, denoted as a; the mixing parameter set includes several mixing parameters, and each set of mixing parameters corresponds to a preset attention coefficient. The priority of each set of mixing parameters is positively correlated with the attention coefficient, the uniformity of the mother liquor, and the feeding speed in each set of mixing parameters respectively;

[0011] Select the target mixing parameter from the mixing parameter set according to the target mixing parameter a for mixing work, including:

[0012] The mixing device performs mixing work with the target mixing parameter a, obtains the change sequence A of the mother liquor uniformity during the mixing work, obtains the stability of the target mixing parameter a according to the change sequence A of the mother liquor uniformity, adjusts the attention coefficient of the target mixing parameter a according to the stability, and re-obtains the target mixing parameter from the mixing parameter set according to the adjusted attention coefficient, denoted as b;

[0013] Use the PID algorithm to change the mixing parameter of the mixing device from a to b, and record the change sequence B of the mother liquor uniformity. Adjust the attention coefficient of b according to the difference between the change sequences A and B of the mother liquor uniformity and the priorities of a and b; then delete the mixing parameter with the smallest attention coefficient in the mixing parameter set, and the mixing device performs mixing work with the target mixing parameter b;

[0014] The difference between the priority corresponding to b with the adjusted attention coefficient and the priority corresponding to a with the adjusted attention coefficient is positively correlated with the difference between A and B;

[0015] Select the target mixing parameter from the deleted mixing parameter set again according to the target mixing parameter b for mixing work.

[0016] Preferably, the specific steps for obtaining the mixing parameter set are as follows:

[0017] When the mixing device mixes the mother liquor, record the mixing parameters used and the uniformity of the mother liquor in the buffer tank; use the mixing parameters with the mother liquor uniformity greater than the first preset threshold as the mixing parameter set.

[0018] Preferably, the specific calculation formula for the priority of each set of mixing parameters is as follows:

[0019] The priority is denoted as Q = w×F + V; where F represents the uniformity of the mother liquor corresponding to each set of mixing parameters, V represents the feeding speed in each mixing parameter, and w represents the attention coefficient of each set of mixing parameters.

[0020] Preferably, obtaining the stability of the target mixing parameter a according to the mother liquor uniformity change sequence A includes the following specific steps:

[0021] Perform linear normalization on the mother liquor uniformity in the mother liquor uniformity change sequence A. The variance of all the mother liquor uniformity after linear normalization is denoted as x, and exp(-x) is used as the stability of the target mixing parameter a, where exp() represents the exponential function with the natural constant as the base.

[0022] Preferably, adjusting the attention coefficient of the target mixing parameter a according to the stability includes the following specific steps:

[0023] The attention coefficient of the target mixing parameter a after adjustment is (1 + h - q)×k; where k represents the attention coefficient of the target mixing parameter a before adjustment, q is a preset adjustment coefficient, and h represents the stability.

[0024] Preferably, adjusting the attention coefficient of b according to the difference between the mother liquor uniformity change sequences A and B and the priorities of a and b includes the following specific steps:

[0025] Obtain the mean value of all the mother liquor uniformity in the mother liquor uniformity change sequence B and denote it as fb, and obtain the mean value of all the mother liquor uniformity in the mother liquor uniformity change sequence A and denote it as fa;

[0026] Let Fab = (fb - fa) / max(fb, fa), where max(fb, fa) represents the maximum value of fb and fa, and Fab represents the difference between the mother liquor uniformity change sequences A and B;

[0027] After the attention coefficient of the target mixing parameter a is adjusted, the priority of a is denoted as Qa; before the attention coefficient of the target mixing parameter b is adjusted, the priority of b is denoted as Qb; assume that the attention coefficient of the target mixing parameter b after adjustment is x, and the priority of the target mixing parameter b obtained according to x is denoted as Qb1; Qb1 = Qb + Fab×p×Qa, then x = (Qb1 - Vb) / wb, where Vb represents the feeding speed in the target mixing parameter b, and wb represents the attention coefficient of the target mixing parameter b before adjustment; p represents the difference attention coefficient.

[0028] Preferably, the specific steps for obtaining the difference attention coefficient are as follows:

[0029] When the target mixing parameter b is different from the target mixing parameter a, the difference attention coefficient is negatively correlated with the stability of the target mixing parameter a;

[0030] When the target blending parameter b is the same as the target blending parameter a, the blending device continues to perform the blending operation with the target blending parameter a, obtains the change sequence A of the mother liquor uniformity again during the blending operation, obtains the stability of the target blending parameter a again according to the change sequence A of the mother liquor uniformity, adjusts the attention coefficient of the target blending parameter a again according to the stability, and re-obtains the target blending parameter b from the blending parameter set again according to the adjusted attention coefficient; when the target blending parameter b is the same as the target blending parameter a again, the blending device continues to perform the blending operation with the target blending parameter a, and so on until the obtained target blending parameter b is different from the target blending parameter a; then sum up the stabilities obtained by the target blending parameter a, denoted as Pa; the difference attention coefficient is negatively correlated with Pa.

[0031] Preferably, the step of reselecting the target blending parameter from the deleted blending parameter set according to the target blending parameter b for the blending operation includes the following specific steps:

[0032] When the blending device performs the blending operation with the target blending parameter b, it obtains the change sequence A of the mother liquor uniformity during the blending operation, and obtains the stability of the target blending parameter b according to the change sequence A of the mother liquor uniformity;

[0033] When the stabilities of both the target blending parameter b and the target blending parameter a are greater than the second preset threshold, the average value of a and b is used as a new blending parameter and added to the blending parameter set.

[0034] Preferably, in the blending parameter set, if the number of blending parameters whose attention coefficients have been adjusted is less than or equal to the preset number, then no blending parameter is deleted.

[0035] The beneficial effects of the technical solution of the present invention are:

[0036] In the online blending device of the present invention, the high powder-water ratio injector uses high-speed water flow to lift the dry powder, so that the dry powder flow collides and mixes with the high-speed water flow, enabling continuous and uniform mother liquor to be produced during online blending of the mother liquor.

[0037] Furthermore, in the present invention, when preparing the mixed mother liquor, by continuously adjusting the attention coefficients of the mixing parameters in the mixing parameter set and deleting inappropriate mixing parameters, it is ensured that the mixing parameter set is continuously updated, so that the target mixing parameters selected from the mixing parameter set have a high mixing efficiency (that is, the mother liquor is mixed relatively evenly and the production of the mother liquor is large), preventing the occurrence of uneven situations such as fish eyes and sticky masses. At the same time, according to the specific process of online mixing, the target mixing parameters are adaptively changed, so that the mixing parameters of the mixing device are not fixed, but dynamically adjusted between different target mixing parameters, and at the same time, the uniformity of the mother liquor is not changed, enabling the mixing device to have good fault tolerance and stability when facing complex and changeable online mixing scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0039] Figure 1 It is a schematic structural diagram of a fully automatic fracturing fluid powder online mixing device provided by an embodiment of the present invention;

[0040] Figure 2 It is a flowchart of a fully automatic fracturing fluid powder online mixing method provided by an embodiment of the present invention.

[0041] In the figure: 1, water supply tank at the fracturing site; 2, pre-pump filter; 3, boost pump; 4, pressure transmitter at the outlet of the boost pump; 5, flowmeter of the boost pump; 6, electric ball valve at the outlet of the boost pump; 7, high powder-water ratio ejector; 8, Roots blower; 9, high-level tuning fork in the dry powder tank; 10, low-level tuning fork in the dry powder tank; 11, dry powder storage truck; 12, dry powder tank; 13, gate valve; 14, weighing instrument; 15, vibrator; 16, cyclone dust collector; 17, reverse-blowing filter cartridge dust collector; 18, air compressor; 19, solenoid valve; 20, first dust removal and blanking valve; 21, second dust removal and blanking valve; 22, screw metering feeder; 23, dry powder hopper; 24, sand mixing truck; 25, suction pump of the sand mixing truck; 26, static mixing and dilution skid; 27, level gauge of the dry powder hopper; 28, mother liquor output pump; 29, mother liquor output flowmeter; 30, pressure transmitter at the outlet of the mother liquor; 31, buffer tank level gauge; 32, buffer tank. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] To further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following will, in conjunction with the accompanying drawings and preferred embodiments, elaborate in detail on the specific implementation manner, structure, features and effects of the fully automatic fracturing fluid powder online mixing device and mixing method proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs.

[0044] Hydraulic fracturing requires a large amount of fracturing fluid to be injected. In the traditional fracturing station liquid preparation, the liquid preparation concentration is lower than 0.4%, and then it is transported to the fracturing site, resulting in a significant increase in cost. An existing method is to use an emulsion prepared from white oil and polymer dry powder, the concentration of which can reach about 40%. After being transported to the site, according to different fracturing stages, the amount of emulsion corresponding to the concentration required for the fracturing operation is input. After the emulsion meets water, a fracturing fluid with the same properties as the traditional fracturing fluid is quickly formed, greatly reducing the cost.

[0045] White oil is a petroleum product with a relatively high cost, and white oil does not play any role in the entire fracturing process. The fully automatic fracturing fluid powder online mixing device and mixing method provided by the present invention can use polymer dry powder to prepare the aqueous solution required for fracturing at the fracturing site, continuously prepare the fracturing fluid online, and ensure that different concentrations and different discharge rates of fracturing fluid can be provided as the fracturing progresses in different stages. This not only solves the problem of the cost of the fracturing fluid, but also makes the on-site chemical storage extremely convenient. The fracturing fluid is used as it is prepared, without waste.

[0046] The following will specifically describe the specific solutions of the fully automatic fracturing fluid powder online mixing device and mixing method provided by the present invention in conjunction with the accompanying drawings.

[0047] Example 1:

[0048] Please refer to Figure 1 , which shows the fully automatic fracturing fluid powder online mixing device provided by an embodiment of the present invention. The polymer dry powder is loaded in the dry powder storage vehicle 11 in the mixing device. The outlet pipeline of the Roots blower 8 is connected to the inlet of the dry powder storage vehicle 11, and the inlet of the dry powder tank 12 in the mixing device is connected to the outlet of the dry powder storage vehicle 11. A dry powder tank low-level tuning fork 10, a weighing instrument 14 and a dry powder tank high-level tuning fork 9 are installed on the dry powder tank 12.

[0049] The mixing working process of the online mixing device includes:

[0050] First, detect whether there is material in the dry powder tank 12. The specific method is as follows: A dry powder tank low-level tuning fork 10 and a weighing instrument 14 are installed on the dry powder tank 12. Obtain in advance the signal values output by the dry powder tank low-level tuning fork 10 and the weighing instrument 14 when there is material in the dry powder tank 12 (that is, when the dry powder just submerges the dry powder tank low-level tuning fork 10), and record them as reference signals. If the signal values output by the powder tank low-level tuning fork 10 and the weighing instrument 14 during the current mixing do not equal or are less than the reference signals, it is determined that the polymer dry powder in the dry powder tank 12 is insufficient. Otherwise, it is determined that the polymer dry powder in the dry powder tank 12 is sufficient.

[0051] When it is detected that the polymer dry powder in the dry powder tank 12 is insufficient, start the Roots blower 8 to feed the dry powder tank 12 under positive pressure. This process requires a two-stage dust removal system to ensure no dust pollution. The specific process is as follows: The blown dry powder first passes through the cyclone dust collector 16 for primary dust removal treatment. A large amount of dust enters the dust discharge port of the cyclone dust collector 16, and the remaining dust enters the reverse blow type filter dust collector 17 through the air flow, and the dust removal process is completed.

[0052] In addition, determine in advance the output signal values of the dry powder tank high-level tuning fork 9 and the weighing instrument 14 when the dry powder just submerges the dry powder tank high-level tuning fork 9, and record them as upper limit signals;

[0053] When the feedback signals of the dry powder tank high-level tuning fork 9 and the weighing instrument 14 are equal to the upper limit signals, stop the Roots blower 8. At this time, the solenoid valve 19 opens. The solenoid valve 19 is installed between the reverse blow type filter dust collector 17 and the air compressor 18; The reverse blow type filter dust collector 17 receives the compressed air of the air compressor 18, blows the filter element of the reverse blow type filter dust collector 17, and discharges the dust to the lower dust discharge port. At the same time, open the first dust removal blanking valve 20 and the second dust removal blanking valve 21 to discharge the dust to the inlet of the spiral metering feeder 22 for reuse. The spiral metering feeder 22 is installed at the discharge port below the dry powder tank 12.

[0054] To ensure the downward flowability of the polymer dry powder, start the vibrator 15 in real time.

[0055] Open the gate valve 13, and the spiral metering feeder 22 transports the polymer dry powder in the dry powder tank 12 to the dry powder hopper 23 at a certain rotation speed; A dry powder hopper level gauge 27 is installed on the dry powder hopper 23 to detect the powder level of the dry powder in the dry powder hopper 23. When the powder level is higher than the set warning value (for example, 20 centimeters), the dry powder hopper level gauge 27 generates an alarm and stops mixing to prevent blockage during the pneumatic conveying of dry powder and affect the mixing effect.

[0056] The clear water outlet of the water supply tank 1 at the fracturing site is connected to the pre-pump filter 2. The clear water is filtered by the pre-pump filter 2 and then pressurized by the booster pump 3. The booster pump 3 uses the pressure transmitter 4 at the outlet of the booster pump to change the pressure of the clear water, and the pressurized clear water obtains the water flow rate using the booster pump flowmeter 5.

[0057] While the screw metering feeder 22 is working, open the electric ball valve 6 at the outlet of the booster pump, then start the booster pump 3, and then the pressurized clear water enters the high powder-water ratio injector 7, and a jet flow is formed in the high powder-water ratio injector 7. The high powder-water ratio injector 7 is also connected to the dry powder hopper 23 through an air transportation pipeline.

[0058] The high-speed water flow generates a high negative pressure and a lifting force in the high powder-water ratio injector 7, which can lift the dry powder in the dry powder hopper 23 into the high powder-water ratio injector 7 and make the lifted dry powder flow at high speed. The high-speed dry powder flow and the high-speed water flow collide and mix in the high powder-water ratio injector 7 to obtain the mother liquor.

[0059] In this embodiment, the clear water and the dry powder collide and mix in the injector, which ensures sufficient mixing of water and powder (suitable for the preparation of high-concentration mother liquor at 25000 PPM, that is, the powder-water ratio is 2.5%), and prevents the appearance of fish eyes and sticky lumps.

[0060] The mixed mother liquor enters the buffer tank 32; the buffer tank liquid level gauge 31 is installed on the buffer tank 32 to detect the liquid level of the mother liquor in the buffer tank 32. When the liquid level reaches the set working liquid level, the mother liquor output pump 28 starts (using variable frequency drive). In order to ensure that the liquid level of the mother liquor in the buffer tank 32 is always kept constant at the working liquid level, in this embodiment, the mother liquor output pump 28 is controlled by the PID algorithm (that is, the mother liquor output pump 28 and the buffer tank liquid level gauge 31 form a closed-loop control).

[0061] In addition, an ultrasonic sensor is installed in the buffer tank 32. The ultrasonic sensor emits ultrasonic waves towards the mother liquor liquid surface and receives the ultrasonic waves reflected from different positions.

[0062] When the ultrasonic wave encounters the interface in the medium (such as the interface between dry powder particles and water), reflection will occur. The intensity of the reflected wave can reflect the particle distribution in the mixed liquid. The reflected wave of a uniform mixed liquid is weak and stable, while the reflected wave of a non-uniform mixed liquid is strong and fluctuating.

[0063] In this embodiment, the intensities of the reflected waves at all positions are linearly normalized, and the variance H of the intensities of the reflected waves at all positions after the linear normalization process is obtained. exp(-H) is used as the uniformity of the mother liquor in the buffer tank 32; exp() represents the exponential function with the natural constant as the base. The greater the uniformity of the mother liquor, the less fluctuation there is in the intensities of the reflected waves at all positions, and the more uniform the mother liquor is mixed.

[0064] The outlet of the buffer tank 32 is connected to the static mixing and dilution skid 26 through the mother liquor output pump 28. In addition, a mother liquor output flowmeter 29 and a mother liquor output pressure transmitter 30 are also connected to the mother liquor output pump 28, which are respectively used to obtain the amount of mother liquor output from the buffer tank 32 and control the pressure of the mother liquor output.

[0065] The buffer tank 32 transports the mother liquor to the mother liquor inlet of the static mixing and dilution skid 26; in addition, the static mixing and dilution skid 26 is connected to the fracturing site water supply tank 1 through a water pipe, and the fracturing site water supply tank 1 provides clear water for the static mixing and dilution skid 26; the static mixing and dilution skid 26 mixes the high-concentration mother liquor and clear water, and the outlet becomes the low-concentration target liquid. The low-concentration target liquid is sucked into the blender truck 24 by the suction pump 25 of the blender truck. In the blender truck 24, the low-concentration target liquid is mixed with sand in the mixing tank and then transported to the fracturing pump and pressed into the formation for rock fracturing.

[0066] In the above working process of the mixing device, the water and powder collide and mix in the ejector, which ensures sufficient mixing of the water and powder and prevents uneven situations such as fisheyes and sticky lumps. However, the premise is that the flow rates of the high-speed water flow and the high-speed dry powder flow and the water-powder ratio should be appropriate, otherwise the uniform mixing of the water and powder still cannot be ensured.

[0067] In this embodiment, the booster pump 3 (specifically, the booster pump flowmeter 5 of the booster pump 3) is controlled to change the flow rate of the water flow. The water pressure is set within a set range (such as 0.4 to 0.8 MPa) by detecting and setting the booster pump pressure transmitter 4. As the booster pump flowmeter 5 changes, the control system adjusts the real-time feeding speed of the screw metering feeder 22 through PID control. When the pressure of the high-speed water flow in the high powder-water ratio ejector 7 is constant, the greater the water flow rate, the faster the feeding speed of the dry powder, otherwise it is slower.

[0068] In this embodiment, the flow rate of the clear water, the pressure of the water flow, and the feeding speed of the dry powder are recorded as the mixing parameters of the mixing device. When the mixing parameters of the mixing device are set to different values, the flow rate and water pressure of the high-speed water flow in the high powder-water ratio ejector 7 and the content of the dry powder in the dry powder flow are all different. Only by setting appropriate mixing parameters can it be ensured that the mother liquor mixed in the high powder-water ratio ejector 7 has the target concentration, is evenly mixed, and does not have fisheyes and sticky lumps.

[0069] Embodiment 2:

[0070] As Figure 2 shown, this embodiment provides a fully automatic online mixing method for fracturing fluid powder, which is used to set appropriate mixing parameters for the mixing device to ensure that when the mixing device works online, it can efficiently produce the mother liquor with the target concentration that is evenly mixed and has no fisheyes and sticky lumps.

[0071] In step S201, when the mixing device mixes the mother liquor, record the mixing parameters used and the uniformity of the mother liquor in the buffer tank; use the mixing parameters with the mother liquor uniformity greater than the first preset threshold as the mixing parameter set.

[0072] First of all, it should be noted that when using hydraulic fracturing technology to extract shale oil, as the fracturing progresses in different stages, fracturing fluids with different concentrations need to be provided, and different concentrations of fracturing fluids need to be prepared with mother liquors of different concentrations. The concentration of the mother liquor required for each stage is recorded as the target concentration, and the value of the target concentration is determined in advance before the mixing device operates.

[0073] When preparing the mother liquor with the target concentration, record the mixing parameters used and the uniformity of the mother liquor in the buffer tank 32, and store them in the MySQL database.

[0074] Read from the database all the mixing parameters during the historical mixing process for preparing the mother liquor with the target concentration, and the uniformity of the mother liquor corresponding to each set of mixing parameters. Use the mixing parameters with the mother liquor uniformity greater than the first preset threshold th1 as the mixing parameter set.

[0075] If the mixing device has not mixed the mother liquor with the target concentration, then it is necessary to manually adjust the mixing parameters of the mixing device to obtain the mother liquor concentration under each mixing parameter, record the mixing parameters that can mix out the mother liquor with the target concentration, and record these parameters in the MySQL database. If the mixing parameter set is empty, then it is necessary to continue to manually adjust the mixing parameters of the mixing device and obtain the mixing parameter set again until there are more than 5 mixing parameters in the mixing parameter set. In other embodiments, when manually adjusting the mixing parameters of the mixing device, if it is impossible to make there be more than 5 mixing parameters in the mixing parameter set, then th1 is successively increased by 10% and the mixing parameter set is obtained again until there are more than 5 mixing parameters in the mixing parameter set.

[0076] In this embodiment, th1 = 0.75 is used as an example for description. In other embodiments, th1 can be set to other values, and this embodiment does not make specific limitations.

[0077] Compared with other mixing parameters stored in the database, the mother liquor obtained under the mixing parameters in the mixing parameter set is relatively uniform. That is, applying the mixing parameters in the mixing parameter set to the mixing device for the current mixing process can obtain a relatively uniform mixed mother liquor.

[0078] This embodiment then uses the mixing parameter set obtained during the historical mixing process to further obtain the mixing parameters that can be used for the current mixing device.

[0079] Step S202: Assign a focus coefficient to each mixing parameter in the mixing parameter set; obtain the priority of each set of mixing parameters based on the focus coefficient, the uniformity of the mother liquor corresponding to each mixing parameter, and the feeding speed in each mixing parameter, and take the mixing parameter with the maximum priority as the target mixing parameter a.

[0080] Assign an initial focus coefficient w to each set of mixing parameters in the mixing parameter set. The focus coefficient is used to describe the attention to the uniformity of the mother liquor mixed under each set of mixing parameters.

[0081] Assume that the number of mixing parameters in the mixing parameter set is denoted as D, and take 1 / D as the initial focus coefficient of each set of mixing parameters.

[0082] Denote the priority of each set of mixing parameters as Q, and let Q = w×F + V. Where w represents the focus coefficient of each set of mixing parameters; F represents the uniformity of the mother liquor corresponding to each set of mixing parameters (read from the database), and V represents the feeding speed in each mixing parameter.

[0083] The priority Q is used to describe the mixing efficiency of the mother liquor. The larger Q is, the more uniform the mother liquor mixed under the mixing parameters, and at the same time, the faster the mother liquor is produced, which further indicates that high-efficiency mixing can be carried out under the mixing parameters. When Q is smaller, it means that the mother liquor obtained under the mixing parameters is more uneven and the mother liquor output is slower, which further indicates that the mixing parameters cannot carry out high-efficiency mixing. Among them, the larger w is, the more attention is paid to the size of the mother liquor uniformity when judging whether the mixing parameters can carry out high-efficiency mixing, and the smaller w is, the less attention is paid to the size of the mother liquor uniformity when judging whether the mixing parameters can carry out high-efficiency mixing.

[0084] In the mixing parameter set, take the mixing parameter with the maximum priority as the target mixing parameter a. The mixing device performs mixing work with the target mixing parameter a. The target mixing parameter a is the most efficient mixing parameter in the historical mixing process. Using it in the current mixing process can ensure the efficient progress of the current mixing to a certain extent.

[0085] Step S203: Obtain the change sequence A of the mother liquor uniformity during the mixing process, obtain the stability of the target mixing parameter a based on the change sequence A of the mother liquor uniformity, adjust the focus coefficient of the target mixing parameter a according to the stability, and re-obtain the target mixing parameter b according to the adjusted focus coefficient.

[0086] During the current mixing process, the mixing parameters of the mixing device are set to a and the mother liquor is mixed.

[0087] Record the uniformity of the mother liquor in the buffer tank 32 in real time during the mixing process. In this embodiment, it is recorded once every 2 seconds. In other embodiments, the recording time interval can be set to other values, and this embodiment does not make specific limitations.

[0088] It should be noted that the mother liquor generated in the high flour-water ratio injector 7 takes a certain time interval to flow into the buffer tank 32 and be detected by the ultrasonic sensor for the uniformity of the mother liquor. Therefore, in order to make the recorded uniformity of the mother liquor correspond to the set mixing parameters, it is necessary to calibrate the uniformity of the mother liquor and the mixing parameters in advance.

[0089] The uniformity of the mother liquor recorded in real time within a preset time period (for example, within 14 seconds) constitutes a time series, denoted as the mother liquor uniformity change sequence A. The stability of the target mixing parameter a is obtained according to the mother liquor uniformity change sequence A. The stability represents the change situation of the uniformity of the mother liquor obtained when the current mixing is carried out using the target mixing parameter a. The larger this value is, the less obvious the change in the uniformity of the mother liquor obtained by mixing, which further indicates that the target mixing parameter a is suitable for the current mixing process and can ensure the stable operation of the mixing device. When the stability is smaller, it indicates that there are obvious changes in the uniformity of the mother liquor obtained by mixing (it is easy to appear uneven situations such as fish eyes and sticky lumps), indicating that the target mixing parameter a is not suitable for the current mixing process and cannot ensure the stable operation of the mixing device (the so-called stable operation means continuously and stably producing uniform mother liquor).

[0090] As an example, obtaining the stability of the target mixing parameter a according to the mother liquor uniformity change sequence A includes:

[0091] The uniformity of the mother liquor in the mother liquor uniformity change sequence A is linearly normalized. The variance of all the linearly normalized mother liquor uniformities is denoted as x, and exp(-x) is used as the stability h of the target mixing parameter a.

[0092] Adjust the attention coefficient of the target mixing parameter a according to the stability. The purpose is to adjust the attention coefficient of the target mixing parameter a according to the change situation of the uniformity of the mother liquor generated by the mixing device under the target mixing parameter a. When the change in the uniformity of the generated mother liquor is more obvious, it indicates that the target mixing parameter a is not conducive to stably generating uniform mother liquor, and at this time, the uniformity of the mother liquor corresponding to the target mixing parameter a is not paid too much attention. When the uniformity of the generated mother liquor is more stable, it indicates that the target mixing parameter a can continuously and stably generate uniform mother liquor, and at this time, more attention needs to be paid to the uniformity of the mother liquor corresponding to the target mixing parameter a.

[0093] As an example, adjusting the attention coefficient of the target mixing parameter a according to the stability includes the formula: the adjusted attention coefficient of the target mixing parameter a is (1 + h - q) × k.

[0094] Where k represents the attention coefficient before the adjustment of the target mixing parameter a, and q is a preset adjustment coefficient. In this embodiment, q = 0.35 is taken as an example for description. In other embodiments, q can be set to other values, which is not specifically limited in this embodiment. In the above formula, when h is less than q, the attention coefficient of the target mixing parameter a after adjustment is reduced compared with the attention coefficient before adjustment; when h is greater than q, the attention coefficient of the target mixing parameter a after adjustment is enlarged compared with the attention coefficient before adjustment.

[0095] After the attention coefficient of the target mixing parameter a is adjusted, within the mixing parameter set, the target mixing parameter is re-obtained and denoted as b (the specific method is the same as above); that is, the priority of each mixing parameter in the mixing parameter set is recalculated, and then the mixing parameter with the highest priority is selected and denoted as b.

[0096] When the target mixing parameter b is different from a, it means that when the target mixing parameter a cannot enable the mixing device to stably mix a uniform mother liquor, there exists a target mixing parameter b that can be used as the mixing parameter in the subsequent mixing process of the mixing device.

[0097] When the target mixing parameter b is the same as a, it means that even if there is a certain instability in the uniformity of the mother liquor mixed under the target mixing parameter a, it is impossible to obtain other mixing parameters more efficient than the target mixing parameter a. Then, the target mixing parameter a is continuously used for mixing in the subsequent process; at the same time, the time series sequence of the mother liquor uniformity recorded within a preset time period (for example, within 14 seconds) is still denoted as the mother liquor uniformity change sequence A, and the stability of the target mixing parameter a is obtained again according to the mother liquor uniformity change sequence A, and the attention coefficient of the target mixing parameter a is adjusted again, so as to re-obtain the target mixing parameter b, and so on, until the obtained target mixing parameter b is different from a, or the mixing process ends; the stability of a obtained in the last time in this process is used as the stability h in the above formula.

[0098] Step S204: Use the PID algorithm to change the mixing parameter of the mixing device from a to b. During the process of changing from a to b, record the mother liquor uniformity change sequence B, adjust the attention coefficient of b according to the difference between the mother liquor uniformity change sequences A and B, and the priorities of a and b, and delete the mixing parameter with the smallest attention coefficient in the mixing parameter set.

[0099] After the attention coefficient of a is reduced, the target mixing parameter b in the mixing parameter set becomes the most efficient mixing parameter. In this embodiment, the PID algorithm is used to control the booster pump pressure transmitter 4, the booster pump flowmeter 5, and the screw metering feeder 22, and the mixing parameter of the mixing device is adjusted from a to b. During the process of adjusting the mixing parameter from a to b, the time series sequence of the mother liquor uniformity is denoted as the mother liquor uniformity change sequence B.

[0100] It should be noted that, as known from the PID algorithm, the PID algorithm continuously adjusts the mixing parameters of the mixing device so that the mixing parameters gradually approach b from a and then stably equal b (in this embodiment, when the mixing parameters are equal to b after the PID algorithm adjusts the mixing parameters three times continuously, it is determined that the mixing parameters stably equal b); in this embodiment, the time interval for the PID algorithm to adjust the mixing parameters is also set to 2 seconds (equal to the sampling interval of the mother liquor uniformity). The above process is a well-known technology in the PID algorithm and will not be specifically described in this embodiment. The purpose of obtaining the mother liquor uniformity change sequence B above is to obtain the change of the mother liquor uniformity when the mixing parameters change between different values.

[0101] The mean value of all the mother liquor uniformities in the mother liquor uniformity change sequence B is denoted as fb, and the mean value of all the mother liquor uniformities in the mother liquor uniformity change sequence A is denoted as fa.

[0102] According to the difference between the mother liquor uniformity change sequences A and B, and the priorities of a and b, the attention coefficient of b is adjusted. This process can not only ensure that there are other mixing parameters that can efficiently mix the mother liquor when the target mixing parameter a cannot ensure the stable mixing of the mother liquor, but also describe the fault tolerance and stability of the mixing device when the mixing parameters change dynamically.

[0103] As an example, adjusting the attention coefficient of b according to the difference between the mother liquor uniformity change sequences A and B, and the priorities of a and b includes the following specific steps:

[0104] Let Fab = (fb - fa) / max(fb, fa), where max(fb, fa) represents the maximum value of fb and fa, and Fab represents the difference between the mother liquor uniformity change sequences A and B.

[0105] After the attention coefficient of the target mixing parameter a is adjusted, the priority of a is denoted as Qa; before the attention coefficient of the target mixing parameter b is adjusted, the priority of b is denoted as Qb; assume that the adjusted attention coefficient of the target mixing parameter b is x, and the priority of the target mixing parameter b obtained according to x is denoted as Qb1 (the calculation method is described in step S202); then let Qb1 = Qb + Fab × Qa, and then x = (Qb1 - Vb) / wb, where Vb represents the feeding speed in the target mixing parameter b, and wb represents the attention coefficient of the target mixing parameter b before adjustment.

[0106] In the above formula, when fb is larger than fa (fb - fa > 0), it indicates that during the adjustment of the mixing parameters of the mixing device, with the change of the mixing parameters, the uniformity of the mother liquor does not decrease. At this time, it shows that it is more appropriate to adjust the mixing parameters from a to b. This can not only avoid the instability of the uniformity of the mother liquor mixed under a, but also increase the production efficiency of the mother liquor. At the same time, the mixing parameters have a certain dynamic adjustment range, enabling the mixing device to have better fault tolerance and stability to cope with complex and changeable on-line mixing scenarios, including abnormal vibrations of the mixing device, equipment failures or unstable operations, residues or blockages in the equipment, inaccurate instrumentation, and other complex and changeable situations in the on-line mixing scenario. At this time, increase the attention coefficient of b, that is, make the uniformity of the mother liquor mixed with the mixing parameter b be more concerned. Compared with fa, the larger fb is, then compared with a, the priority corresponding to b after the adjustment of the attention coefficient is greater than that of a.

[0107] When fb is smaller than fa (fb - fa < 0), it indicates that during the adjustment of the mixing parameters of the mixing device, with the change of the mixing parameters, the uniformity of the mother liquor decreases significantly. At this time, it shows that it is not appropriate to adjust the mixing parameters from a to b. Although it avoids the instability of the uniformity of the mother liquor under the mixing parameter a to a certain extent, the mixing parameters cannot maintain the stable and uniform mixing of the mother liquor during dynamic adjustment, and uneven situations such as fish eyes and sticky clusters are likely to occur. The mixing device does not have good fault tolerance and stability and cannot face complex and changeable on-line mixing scenarios. At this time, reduce the attention coefficient of b. Compared with fa, the smaller fb is, then compared with a, the difference in the priority corresponding to b after the adjustment of the attention coefficient is not too large compared with that of a.

[0108] When Qb1 < Qa, let Qb1 = 1.01 × Qa. The purpose is: because the above adjustment process of the attention coefficient of b is carried out when the mixing parameters are adjusted from a to b, it is necessary to ensure that the priority of b is still greater than that of a.

[0109] In the set of mixing parameters, delete the mixing parameter with the smallest attention coefficient.

[0110] It should be noted that in the set of mixing parameters, if the number of mixing parameters whose attention coefficients have been adjusted is less than or equal to 5, then no mixing parameter is deleted.

[0111] Step S205: Select the target mixing parameter from the set of mixing parameters after deletion again for the mixing work.

[0112] In the above steps, after the mixing parameters of the mixing device are changed from a to b, the attention coefficient of b is adjusted, and then the mixing device mixes with the target mixing parameter b, and then repeat the steps of S202 to S204, specifically:

[0113] During this blending process, the uniformity of the mother liquor in the buffer tank 32 is recorded in real time. Within a preset time period, the uniformity of the mother liquor recorded in real time constitutes a time series, which is denoted as the mother liquor uniformity change sequence A again. The stability of the target blending parameter b is obtained based on the mother liquor uniformity change sequence A.

[0114] It should be noted that when the stabilities of both a and b are greater than the second preset threshold th2, the mean value of a and b is added as a new blending parameter to the blending parameter set.

[0115] The mean value of a and b means that the water volume, water pressure, and feeding speed in a and b are respectively averaged.

[0116] According to the stability, the attention coefficient of the target blending parameter b is adjusted, and the target blending parameter c is obtained again based on the adjusted attention coefficient. Then, using the PID algorithm, the blending parameter of the blending device is changed from b to c. During the process of changing from b to c, the mother liquor uniformity change sequence is recorded and denoted as B again. Based on the difference between the mother liquor uniformity change sequences A and B, and the priorities of b and c, the attention coefficient of c is adjusted, and the blending parameter with the smallest attention coefficient in the blending parameter set is deleted.

[0117] It should be noted that when the stabilities of both b and c are greater than the second preset threshold th2, the mean value of b and c is added as a new blending parameter to the blending parameter set.

[0118] Then, the blending device blends with the target blending parameter c. Similarly, the stability of the target blending parameter c is obtained. According to the stability, the attention coefficient of the target blending parameter c is adjusted, and the target blending parameter d is obtained again based on the adjusted attention coefficient. Then, using the PID algorithm, the blending parameter of the blending device is changed from c to d. During the process of changing from c to d, the mother liquor uniformity change sequence B is recorded. Based on the difference between the mother liquor uniformity change sequences A and B, and the priorities of c and d, the attention coefficient of d is adjusted, and the blending parameter with the smallest attention coefficient in the blending parameter set is deleted.

[0119] It should be noted that when the stabilities of both c and d are greater than the second preset threshold th2, the mean value of c and d is added as a new blending parameter to the blending parameter set.

[0120] And so on until the blending process ends (that is, the blending ends after obtaining the mother liquor with the required flow rate). Among them, when the number of blending parameters in the blending parameter set is less than or equal to 5, no blending parameter in the blending parameter set is deleted anymore.

[0121] In this embodiment, th2 = 0.5 is taken as an example for description. In other embodiments, th2 can be set to other values, and this example is not specifically limited.

[0122] In the above process, by continuously adjusting the attention coefficients of the mixing parameters in the mixing parameter set and deleting inappropriate mixing parameters, it is ensured that the mixing parameter set is continuously updated, so that the target mixing parameters selected from the mixing parameter set have a high mixing efficiency (that is, the mother liquor is mixed more evenly and the production of the mother liquor is larger). At the same time, according to the specific process of online mixing, the target mixing parameters are adaptively changed, so that the mixing parameters of the mixing device are not fixed. At the same time, when dynamically adjusting between different target mixing parameters, the uniformity of the mother liquor will not be changed, so that the mixing device has good fault tolerance and stability in the face of complex and changeable online mixing scenarios.

[0123] Finally, after the mixing of the mother liquor with the current target concentration is completed, the mixing parameters used in this process and the corresponding mother liquor uniformity are stored in the database.

[0124] When it is necessary to prepare mother liquor with other target concentrations next time, the mixing is carried out again according to the methods of steps S201 to S205 above. With multiple mixings, the more mixing parameters stored in the database, and along with the continuous update of the mixing parameter set, the mixing device can operate more and more efficiently.

[0125] Embodiment Three:

[0126] The difference between this embodiment and Embodiment Two is that when calculating the difference between the mother liquor uniformity change sequences A and B, and the priorities of a and b, the attention coefficient of b is adjusted, and further combined with the mother liquor uniformity situation during mixing under the target mixing parameter a.

[0127] In this embodiment, calculating the difference between the mother liquor uniformity change sequences A and B, and adjusting the attention coefficient of b according to the priorities of a and b includes the following steps:

[0128] As can be seen from step S203 in Embodiment One, after obtaining the target mixing parameter a, the mixing parameters of the mixing device are set to a and mixing work is carried out. The stability of a is obtained according to the mother liquor uniformity change sequence A, and the attention coefficient of a is adjusted according to this stability, and then the target mixing parameter b is obtained. The obtained b may be the same mixing parameter as a. If it is the same mixing parameter, then the target mixing parameter b is obtained again according to the method in step S203 to make it different from a, and then the mixing parameters of the mixing device are adjusted from a to b.

[0129] From this process, another target mixing parameter b is obtained according to the target mixing parameter a. In this process, the stability of a has one or more values; the sum of all stabilities of a is obtained and denoted as Pa;

[0130] Suppose the adjusted attention coefficient of the target blending parameter b is x, and the priority of the target blending parameter b obtained according to x is denoted as Qb1; then let Qb1 = Qb + Fab × exp(-Pa) × Qa, so x = (Qb1 - Vb) / wb, where Vb represents the feeding speed in the target blending parameter b, and wb represents the attention coefficient of the target blending parameter b before adjustment.

[0131] exp(-Pa) represents the differential attention coefficient p. The larger Pa is, that is, the smaller exp(-Pa) is, it indicates that the uniformity of the mother liquor blended under the target blending parameter a is relatively stable. At this time, when adjusting the attention coefficient of the target blending parameter b, the change in the uniformity of the mother liquor during the process of adjusting the blending parameter from a to b is not overly concerned (that is, the size of Fab is not overly concerned), so as to avoid adjusting the attention coefficient of b too large. For example, when Fab is greater than 0, avoid adjusting the attention coefficient of b too large, which may cause the target blending parameter a to be prematurely deleted from the blending parameter set; another example is when Fab is less than 0, the attention coefficient of b will be even smaller, so that when the uniformity of the mother liquor decreases during the process of adjusting from a to b, the target blending parameter b also has the possibility of being deleted.

[0132] When Pa is smaller, that is, exp(-Pa) is larger, it indicates that the uniformity of the mother liquor blended under the target blending parameter a is unstable, and uneven situations such as fish eyes and sticky lumps are likely to occur. At this time, when adjusting the attention coefficient of the target blending parameter b, it is more necessary to pay attention to the change in the uniformity of the mother liquor during the process of adjusting the blending parameter from a to b (that is, to pay more attention to the size of Fab), so as to avoid adjusting the attention coefficient of b too small. For example, when Fab is less than 0, avoid adjusting the attention coefficient of b too small, which may lead to the situation where the target blending parameter a cannot be deleted from the blending parameter set in a timely manner.

[0133] The above method for obtaining the adjusted attention coefficient of b further realizes the effective update of the attention coefficient, enables the blending parameters in the blending parameter set to be reasonably updated, and further ensures that when the blending device uses the blending parameters in the blending parameter set to blend the mother liquor, the uniformity is increased and uneven situations such as fish eyes and sticky lumps are avoided.

[0134] The above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. The online mixing method of fully automatic fracturing fluid powder is characterized in that The method includes the following steps: Output clear water by using the water supply tank (1) at the fracturing site. After passing through the booster pump (3), the clear water forms a jet in the high powder-water ratio injector (7); use the screw metering feeder (22) to convey the polymer dry powder in the dry powder tank (12) to the dry powder hopper (23); the negative pressure of the jet in the high powder-water ratio injector (7) lifts the polymer dry powder in the dry powder hopper (23) into the high powder-water ratio injector (7), and the polymer dry powder in the high powder-water ratio injector (7) collides and mixes with the jet to obtain the mother liquor, and the mother liquor enters the buffer tank (32); The feeding speed of the dry powder hopper (23), the water volume output by the water supply tank (1) at the fracturing site, and the water pressure output by the booster pump (3) are recorded as a set of mixing parameters of the mixing device; Obtain the mixing parameter with the highest priority from the mixing parameter set as the target mixing parameter, denoted as a; the mixing parameter set includes several mixing parameters, and each set of mixing parameters corresponds to a preset attention coefficient. The priority of each set of mixing parameters is positively correlated with the attention coefficient, the mother liquor uniformity, and the feeding speed in each set of mixing parameters respectively; Select the target mixing parameter from the mixing parameter set according to the target mixing parameter a for mixing work, including: The mixing device performs mixing work with the target mixing parameter a, obtains the mother liquor uniformity change sequence A during the mixing work process, obtains the stability of the target mixing parameter a according to the mother liquor uniformity change sequence A, adjusts the attention coefficient of the target mixing parameter a according to the stability, and re-obtains the target mixing parameter from the mixing parameter set according to the adjusted attention coefficient, denoted as b; Use the PID algorithm to change the mixing parameters of the mixing device from a to b, and record the mother liquor uniformity change sequence B. Adjust the attention coefficient of b according to the difference between the mother liquor uniformity change sequences A and B, and the priorities of a and b; then delete the mixing parameter with the smallest attention coefficient in the mixing parameter set, and the mixing device performs mixing work with the target mixing parameter b; The difference between the priority corresponding to b with the adjusted attention coefficient and the priority corresponding to a with the adjusted attention coefficient is positively correlated with the difference between A and B; Select the target mixing parameter again from the deleted mixing parameter set according to the target mixing parameter b for mixing work.

2. The online mixing method of the fully automatic fracturing fluid powder according to claim 1, wherein, The specific steps for obtaining the mixing parameter set are as follows: When the mixing device mixes the mother liquor, record the mixing parameters used and the mother liquor uniformity in the buffer tank (32); use the mixing parameters with the mother liquor uniformity greater than the first preset threshold as the mixing parameter set.

3. The fully automatic fracturing fluid powder online mixing method according to claim 1, characterized in that, The specific calculation formula for the priority of each set of mixing parameters is as follows: The priority is denoted as Q = w×F + V; where F represents the mother liquor uniformity corresponding to each set of mixing parameters, V represents the feeding speed in each mixing parameter, and w represents the attention coefficient of each set of mixing parameters.

4. The fully automatic fracturing fluid powder online mixing method according to claim 1, wherein The specific steps for obtaining the stability of the target mixing parameter a according to the mother liquor uniformity change sequence A include: Perform linear normalization on the mother liquor uniformity in the mother liquor uniformity change sequence A. Denote the variance of all mother liquor uniformities after linear normalization as x, and take exp(-x) as the stability of the target mixing parameter a, where exp() represents the exponential function with the natural constant as the base.

5. The fully automatic fracturing fluid powder online mixing method according to claim 1, characterized in that, The specific steps for adjusting the attention coefficient of the target mixing parameter a according to the stability are as follows: The attention coefficient after adjusting the target mixing parameter a is (1 + h - q) × k; where k represents the attention coefficient before adjusting the target mixing parameter a, q is a preset adjustment coefficient, and h represents the stability.

6. The online mixing method of the full-automatic fracturing fluid powder according to claim 1, characterized in that, The specific steps for adjusting the attention coefficient of b according to the difference between the mother liquor uniformity change sequences A and B and the priorities of a and b are as follows: Obtain the mean value of all mother liquor uniformities in the mother liquor uniformity change sequence B and denote it as fb, and obtain the mean value of all mother liquor uniformities in the mother liquor uniformity change sequence A and denote it as fa; Let Fab = (fb - fa) / max(fb, fa), where max(fb, fa) represents the maximum value of fb and fa, and Fab represents the difference between the mother liquor uniformity change sequences A and B; After adjusting the attention coefficient of the target mixing parameter a, denote the priority of a as Qa; before adjusting the attention coefficient of the target mixing parameter b, denote the priority of b as Qb; assume the attention coefficient after adjusting the target mixing parameter b is x, and the priority of the target mixing parameter b obtained according to x is denoted as Qb1; Qb1 = Qb + Fab × p × Qa, then x = (Qb1 - Vb) / wb, where Vb represents the feeding speed in the target mixing parameter b, and wb represents the attention coefficient before adjusting the target mixing parameter b; p represents the difference attention coefficient.

7. The fully automatic online mixing method of fracturing fluid powder according to claim 6, wherein The specific steps for obtaining the difference attention coefficient are as follows: When the target mixing parameter b is different from the target mixing parameter a, the difference attention coefficient is negatively correlated with the stability of the target mixing parameter a; When the target mixing parameter b is the same as the target mixing parameter a, the mixing device continues to perform mixing work with the target mixing parameter a, and obtain the mother liquor uniformity change sequence A during the mixing work again. Obtain the stability of the target mixing parameter a again according to the mother liquor uniformity change sequence A, adjust the attention coefficient of the target mixing parameter a again according to the stability, and obtain the target mixing parameter b again from the mixing parameter set according to the adjusted attention coefficient. When the target mixing parameter b is the same as the target mixing parameter a again, the mixing device continues to perform mixing work with the target mixing parameter a, and so on until the obtained target mixing parameter b is different from the target mixing parameter a; then sum up the several stabilities obtained for the target mixing parameter a and denote it as Pa; the difference attention coefficient is negatively correlated with Pa.

8. The fully automatic online mixing method of fracturing fluid powder according to claim 1, characterized in that, The specific steps for reselecting the target mixing parameter from the deleted mixing parameter set according to the target mixing parameter b for mixing work are as follows: When the mixing device performs mixing work with the target mixing parameter b, obtain the mother liquor uniformity change sequence A during the mixing work, and obtain the stability of the target mixing parameter b according to the mother liquor uniformity change sequence A; When the stabilities of both the target blending parameter b and the target blending parameter a are greater than the second preset threshold, the average value of a and b is used as a new blending parameter and added to the blending parameter set.

9. The online mixing method of the full-automatic fracturing fluid powder according to claim 1, characterized in that In the blending parameter set, if the number of blending parameters with adjusted attention coefficients is less than or equal to the preset number, then no blending parameter is deleted.

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