Dry powder blending method

Abstract

The invention relates to a dry powder mixing method. The method comprises the following steps: putting a dry powder material into a stock bin; the dry powder materials are conveyed to a mixing center through a conveying device according to the given quantity; liquid used for being mixed with the dry powder materials is sprayed to the mixing center, and the dry powder materials on the conveying device are sucked into the mixing center through negative pressure generated by liquid spraying; a stirring device is used for stirring the substances in the mixing center, so that the dry powder material and the liquid are uniformly mixed; and conveying the uniformly mixed slurry to a fracturing blender truck or a petroleum field use unit. The method is used for mixing and preparing working fluid such as petroleum fracturing fluid and drilling fluid, and solves the problems that an existing mixing process is low in efficiency and poor in uniformity.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of oil exploitation engineering, and particularly relates to a dry powder mixing method. BACKGROUND

[0002] In the process of oil exploitation, the performance of working fluids such as fracturing fluid and drilling fluid is crucial, and the configuration quality will directly affect the fracturing stimulation effect and drilling speed. These working fluids usually need to uniformly mix a plurality of dry powder additives (such as thickening agent, gel breaker, clay stabilizer, etc.) with water or other liquids to ensure the stability of the slurry performance. However, the existing dry powder mixing method has the following disadvantages: the traditional batch stirring is prone to agglomeration and stratification, resulting in insufficient mixing precision; the manual intermittent stirring cannot meet the demand of large-scale continuous operation; the low degree of automation makes it difficult to realize continuous and accurate proportioning of multiple powders and automatic control; and the open operation leads to serious dust pollution, which does not meet the environmental protection and safety requirements.

[0003] Therefore, there is an urgent need for an efficient continuous dry powder mixing method to improve the uniformity, efficiency and automation level of dry powder liquid mixing, so as to meet the requirements of environmental protection, high efficiency and intelligentization of the oil industry. SUMMARY

[0004] In order to solve all or part of the above problems, the purpose of the present application is to provide a dry powder mixing method, which solves the problem of low efficiency and poor uniformity of the existing mixing process.

[0005] According to one aspect of the present application, a dry powder mixing method is provided, comprising: putting dry powder materials into a stock bin; transporting the dry powder materials to a mixing center through a conveying device according to a given amount; spraying a liquid used for mixing with the dry powder materials to the mixing center, and using the negative pressure generated by the liquid spraying to suck the dry powder materials on the conveying device into the mixing center; stirring the substances in the mixing center by a stirring device to uniformly mix the dry powder materials with the liquid; and transporting the uniformly mixed slurry to a sand mixing truck or an on-site use unit of oil field.

[0006] Further, the dry powder materials are put into the stock bin by using a lifting device to hoist the dry powder materials to a feeding platform, and then putting the dry powder materials after bag breaking on the feeding platform into the stock bin.

[0007] Further, before the dry powder material is transported to the mixing center by the conveying device according to the given amount, the method further comprises: obtaining the real-time weight of the dry powder material in the silo, so that the weight of the dry powder material transported to the mixing center is equal to the given amount of the dry powder material.

[0008] Further, the obtaining the real-time weight of the dry powder material in the silo, so that the weight of the dry powder material transported to the mixing center is equal to the given amount of the dry powder material specifically comprises: obtaining a first weight of the dry powder material in the silo before the dry powder material is transported by the conveying device; and obtaining a second weight of the dry powder material remaining in the silo after the transportation is completed according to the given amount of the dry powder material, and controlling the conveying device to stop transporting the dry powder material when the real-time weight of the dry powder material in the silo is equal to the second weight, so that the weight of the dry powder material transported to the mixing center is equal to the given amount of the dry powder material. Further, the spraying the liquid used for mixing with the dry powder material to the mixing center, and using the negative pressure generated by the liquid spraying to suck the dry powder material on the conveying device into the mixing center specifically comprises: spraying the liquid used for mixing with the dry powder material to the mixing center at a spraying pressure of 0.2-1.0 MPa, and using the negative pressure generated by the liquid spraying to suck the dry powder material on the conveying device into the mixing center.

[0009] Further, during the process of spraying the liquid to the mixing center, the included angle between the sprayed liquid and the horizontal plane is controlled to be 15-45°.

[0010] Further, the stirring the substance in the mixing center by the stirring device to make the dry powder material and the liquid mix uniformly further comprises: stirring the substance in the mixing center by a first impeller with a diameter of 250-350 mm at a rotating speed of 0-200 r / min; and stirring the substance in the mixing center by a second impeller with a diameter of 70-90 mm at a rotating speed of 0-800 r / min to make the dry powder material and the liquid mix uniformly.

[0011] Further, the conveying the mixed uniform slurry to the sand mixing truck or the on-site use unit of oil specifically comprises: conveying the mixed uniform slurry to the sand mixing truck or the on-site use unit of oil through a closed pipeline, and collecting the pressure and concentration information of the slurry, and collecting the transportation speed of the slurry during the conveying of the mixed uniform slurry to the sand mixing truck or the on-site use unit of oil; and collecting the real-time feeding speed of the conveying device and the real-time spraying flow of the liquid. Furthermore, after the uniformly mixed slurry is transported to the sand mixing truck or the oilfield application unit, the method further includes: controlling the feeding speed of the conveying device, the injection flow rate of the liquid, and the transport speed of the slurry based on the collected slurry pressure and concentration information, the slurry transport speed, the real-time feeding speed of the conveying device, and the real-time injection flow rate of the liquid, so as to control the powder-liquid ratio to be 1%~2%.

[0012] Furthermore, the dry powder material is guar gum powder.

[0013] As can be seen from the above technical solution, the dry powder mixing method provided by the present invention has the following beneficial effects: The method of the present invention is used for mixing and preparing working fluids such as oil fracturing and drilling fluids. The mixing method of the present invention solves the problems of low efficiency and poor uniformity of existing mixing processes. Compared with traditional mechanical stirring methods that rely on a single impeller, this invention forms a three-stage mixing mechanism by spraying liquid for initial mixing, macroscopic circulation stirring of the first impeller, and microscopic shear stirring of the second impeller. This physically breaks the hydrogen bonds and van der Waals forces between powder particles at the moment of powder feeding, effectively eliminating phenomena such as agglomeration and clumping, improving mixing efficiency, and significantly reducing mixing time. The mixing method of the present invention can realize the on-demand mixing and immediate use of qualified working fluid from feeding, thereby improving the mixing efficiency several times and seamlessly meeting the continuous and large-scale fluid supply needs of large-scale fracturing operations. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a dry powder mixing method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the equipment used in a dry powder mixing method according to an embodiment of the present invention. Detailed Implementation

[0015] To better understand the purpose, structure, and function of this invention, a dry powder mixing method of this invention will be described in further detail below with reference to the accompanying drawings.

[0016] like Figure 1 As shown, it illustrates a method for mixing dry powder according to an embodiment of the present invention, comprising: S001: Discharge the dry powder material into the silo; S002: Transport the dry powder material to the mixing center in a given quantity via a conveying device; S003: The liquid used for mixing with dry powder materials is sprayed into the mixing center, and the negative pressure generated by the liquid spray is used to draw the dry powder materials on the conveying device into the mixing center. S004: the mixing center is stirred by a stirring device to uniformly mix the dry powder material with the liquid; and S005: the mixed slurry is transported to a sand mixing vehicle or an oil field use unit.

[0017] The method of the embodiment of the present application is used for mixing and configuring working fluid such as oil fracturing fluid and drilling fluid.

[0018] The dry powder material in S001 is guar gum powder or other high-viscosity dry powder.

[0019] S001: the dry powder material is put into the bin, specifically, the dry powder material is hoisted to a feeding platform by a hoisting device, and the dry powder material after bag breaking on the feeding platform is put into the bin.

[0020] The dry powder material of the embodiment is hoisted to the feeding platform by the hoisting device, thereby freeing manpower, reducing the contact between manpower and the dry powder material, and improving the transportation and feeding efficiency of the dry powder material.

[0021] For the bin, two parallel ton-level bins are used, that is, a bin with a single volume of 1 ton is used.

[0022] Before S002, the method of the embodiment of the present application further includes obtaining the real-time weight of the dry powder material in the bin, so that the weight of the dry powder material transported to the mixing center is equal to the given amount of the dry powder material.

[0023] The purpose of obtaining the real-time weight of the dry powder material in the bin is to timely know the weight of the dry powder material transported to the mixing center, so that the weight of the dry powder material transported to the mixing center is equal to the given amount of the dry powder material, so as to obtain the slurry with the required concentration after mixing with the corresponding liquid.

[0024] The real-time weight of the dry powder material in the silo is obtained, so that the weight of the dry powder material transported to the mixing center is equal to the given amount of the dry powder material, specifically: a first weight of the dry powder material in the silo before the conveying device transports the dry powder material is obtained; and a second weight of the dry powder material remaining in the silo after the transportation is completed is obtained according to the given amount of the dry powder material, and the conveying device is controlled to stop transporting the dry powder material when the real-time weight of the dry powder material in the silo is equal to the second weight, so that the weight of the dry powder material transported to the mixing center is equal to the given amount of the dry powder material.

[0025] Specifically, the given amount of the dry powder material is set as m, the first weight of the dry powder material in the silo before the conveying device transports the dry powder material is m1, and the second weight of the dry powder material remaining in the silo after the transportation is completed is m2, so that the weight of the dry powder material transported to the mixing center is equal to the given amount of the dry powder material, and m = m1-m2 is satisfied among the three. Therefore, in the case of obtaining the first weight of the dry powder material in the silo before the transportation and obtaining the real-time weight of the dry powder material in the silo, the purpose that the weight of the dry powder material transported to the mixing center is equal to the given amount of the dry powder material can be achieved by controlling the real-time weight, specifically, by controlling the conveying device to stop transporting the dry powder material when the real-time weight of the dry powder material in the silo is equal to the second weight.

[0026] Specifically, the first weight of the dry powder material in the silo before the conveying device transports the dry powder material and the real-time weight of the dry powder material in the silo can be obtained by setting a weighing unit at the bottom of the silo.

[0027] For the conveying device of S002, for example, a screw conveyor is set, so that continuous quantitative supply of the powder can be achieved by precisely adjusting the real-time speed of the screw conveyor. A fully enclosed pipeline is used in the conveying process of the screw conveyor, so as to further reduce dust pollution.

[0028] The setting of the embodiment of the present application achieves the purpose of precisely controlling the feeding.

[0029] S003 sprays the liquid used for mixing with the dry powder material to the mixing center, and the dry powder material on the conveying device is sucked into the mixing center by the negative pressure generated by the liquid spraying, specifically: the liquid used for mixing with the dry powder material is sprayed to the mixing center at a spraying pressure of 0.2-1.0 MPa, and the dry powder material on the conveying device is sucked into the mixing center by the negative pressure generated by the liquid spraying.

[0030] In the embodiment, the dry powder material is sucked into the mixing center by the negative pressure generated by the high-pressure sprayed liquid.

[0031] Specifically, the high-speed nozzle is arranged on the top liquid input end of the mixing center, liquid sprayed from the high-speed nozzle can form a strong jet, and the jet flow produces a turbulent effect when it contacts the powder, which destroys the agglomeration of the powder and promotes the uniform dispersion and mixing of the powder, thereby accelerating the wetting and dispersion.

[0032] The jet pressure of the liquid is, for example, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, or 1.0 MPa.

[0033] Again, the angle between the jet liquid and the horizontal plane during the process of jetting the liquid to the mixing center is controlled to be 15-45°. For this angle, for example, it is set to 15°, 20°, 25°, 30°, 35°, 40°, or 45°.

[0034] And for the jet pressure and the angle of the embodiment of the application, when the jet pressure is set to 0.6 MPa and the angle is set to 30°, the optimal balance between energy consumption and dispersion effect can be achieved.

[0035] S004 The stirring device is used to stir the substances in the mixing center to uniformly mix the dry powder material and the liquid, which further comprises: a first impeller with a diameter of 250-350 mm is used to stir the substances in the mixing center at a speed of 0-200 r / min; and a second impeller with a diameter of 70-90 mm is used to stir the substances in the mixing center at a speed of 0-800 r / min, so as to uniformly mix the dry powder material and the liquid.

[0036] In this embodiment, the mixing center is provided with a double-impeller stirring device, the first impeller is a low-speed large-diameter impeller, which is used for macro-stirring and promoting the circulation of the mixture of liquid and powder to prevent the dry powder material from settling. For example, the diameter of the first impeller is 250 mm, 260 mm, 270 mm, 280 mm, 290 mm, 300 mm, 310 mm, 320 mm, 330 mm, 340 mm, or 350 mm. For example, the speed of the first impeller is 40 r / min, 80 r / min, 120 r / min, 160 r / min, or 200 r / min.

[0037] The second impeller is a high-speed small-diameter impeller for micro-dispersion. A strong shearing force can be generated by high-speed rotation of the second impeller to finely disperse the slurry, so as to ensure that all powder particles are completely depolymerized and mixed with liquid molecules at the molecular level, so that the powder dispersion is further mixed with the liquid to make the powder dispersion uniformly mixed with the liquid. In specific implementation, for example, the diameter of the second impeller is 70 mm, 75 mm, 80 mm, 85 mm or 90 mm, and for another example, the rotational speed of the second impeller is 100 r / min, 200 r / min, 300 r / min, 400 r / min, 500 r / min, 600 r / min, 700 r / min or 800 r / min.

[0038] Compared with the traditional method relying on mechanical stirring of a single impeller, the traditional method is prone to forming fisheyes for high-viscosity powders such as guar gum. The embodiment of the present application forms a three-level mixing mechanism by preliminary mixing of liquid, macro-circulating stirring of the first impeller and micro-shearing stirring of the second impeller, so as to physically break the hydrogen bonds and van der Waals forces between the powders at the moment of powder feeding, effectively eliminate the phenomena of agglomeration and caking, and improve the mixing efficiency while greatly reducing the mixing time.

[0039] S005 delivering the uniformly mixed slurry to a sand mixing truck or an oil field use unit specifically includes: delivering the uniformly mixed slurry to the sand mixing truck or the oil field use unit through a sealed pipeline, collecting pressure and concentration information of the slurry, and collecting a transportation speed of the slurry in the process of delivering the uniformly mixed slurry to the sand mixing truck or the oil field use unit; and collecting a real-time feeding speed of the delivery device and a real-time injection flow rate of the liquid.

[0040] After S005 delivering the uniformly mixed slurry to the sand mixing truck or the oil field use unit, the method further includes: controlling the feeding speed of the delivery device, the injection flow rate of the liquid and the transportation speed of the slurry according to the collected pressure and concentration information of the slurry, the transportation speed of the slurry, the real-time feeding speed of the delivery device and the real-time injection flow rate of the liquid, so as to control the powder-liquid ratio to be 1% to 2%.

[0041] Specifically, the uniformly mixed slurry is delivered to the sand mixing truck or the oil field use unit through a sealed pipeline; the transportation speed of the slurry is collected in the process of delivering the slurry, and the corresponding flow rate, concentration and pressure information of the slurry and other information are collected; and the real-time feeding speed of the delivery device and the real-time injection flow rate of the liquid and other key working parameters are collected; and then the central control system dynamically adjusts each execution unit according to the collected feedback signals to ensure the stability of the final mixed solution effect.

[0042] For another example, if the concentration of the slurry is determined to be low according to the concentration of the collected slurry, the conveying speed of the dry powder material is increased on the basis of the current uniform speed of the dry powder material, and the liquid injection flow is reduced on the basis of the current real-time injection flow, so that the concentration of the slurry can be restored to normal.

[0043] The setting of this step can achieve the purposes of real-time control of the conveying speed of the slurry and collection of the data related to the discharging data, so as to facilitate control of the feeding speed of the conveying device and control of the amount of liquid injected into the mixing center according to the collected information, and finally achieve closed-loop control.

[0044] In specific implementation, for example, a data collection center and a PLC control system are set up, the data collection center is used to collect relevant parameters, the data collection center includes an electromagnetic flowmeter, a concentration sensor and a pressure sensor arranged in the conveying pipeline downstream of the mixing center, the PLC control system receives the relevant operating parameters fed back by the data collection center, and adjusts the parameters in real time according to the preset instructions so that they return to the set values, a motor-operated regulating valve can also be arranged in the conveying pipeline downstream of the mixing center as needed to control the output rate of the slurry, a safety valve can also be arranged on the conveying device between the silo and the mixing center and the liquid pipeline conveying the liquid to the mixing center as needed, the safety valve is used to stop the corresponding pipeline in the event of an abnormal situation, and the conveying pipeline of the slurry in the embodiment of the application is designed to be anti-blocking and wear-resistant to ensure long-term stable operation.

[0045] The method of the embodiment of the application is further described as follows: Figure 2 As shown in the figure, first, the dry powder material is lifted to the feeding platform by the lifting device, and the dry powder material after bag breaking on the feeding platform is fed into the two silos, then the dry powder material in the two silos is conveyed to the mixing center by the conveying device, the liquid is injected into the mixing center through the high-speed nozzle, the negative pressure generated during the injection of the liquid into the mixing center sucks the dry powder material on the conveying device into the mixing center, so that the purpose of feeding the dry powder material into the mixing center is achieved, then the dry powder material and the liquid in the mixing center form the slurry under the stirring of the first impeller and the second impeller, the slurry is conveyed to the sand mixing truck or the oil field use unit, the information of the slurry is collected by the data collection center during the conveying of the slurry, so as to facilitate the PLC control system to control various actuators according to the information of the slurry, such as the conveying device and the high-speed nozzle, to achieve closed-loop control, and the downstream of the mixing center is also provided with a motor-operated regulating valve, which is also controlled by the PLC control system.

[0046] The closed-loop control setting of the embodiment of the present application enables the method of the embodiment of the present application to run uninterruptedly for 7x24 hours, avoids the disadvantages brought by batch production, and can realize on-demand mixing and on-demand use from feeding to qualified working fluid, thereby improving the mixing efficiency by several times and meeting the continuous and large liquid supply demand of large-scale fracturing operation seamlessly; and the method of the embodiment of the present application adopts airtight mixing center and closed pipeline transportation, thereby greatly reducing dust pollution.

[0047] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in the present application shall have the general meanings understood by the skilled in the art to which the present application belongs.

[0048] In addition, the terms "one", "two" and the like are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implying the number of the technical features indicated. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0049] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrated; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0050] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the description of the present application. Especially, as long as there is no structural conflict, each technical feature mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for mixing dry powders, characterized in that, include: Dispose of the dry powder material into the silo; The dry powder material is transported to the mixing center in a given quantity via a conveying device; The liquid used for mixing with the dry powder material is sprayed into the mixing center, and the negative pressure generated by the liquid spraying is used to draw the dry powder material on the conveying device into the mixing center. The materials in the mixing center are stirred using a stirring device to ensure that the dry powder and liquid are mixed evenly; and The well-mixed slurry is transported to the sand mixing truck or the oilfield application unit.

2. The dry powder mixing method according to claim 1, characterized in that, The process of feeding the dry powder material into the silo specifically involves: using a lifting device to hoist the dry powder material to the feeding platform, and feeding the dry powder material after the bag is broken on the feeding platform into the silo.

3. The dry powder mixing method according to claim 1, characterized in that, Before transporting the dry powder material to the mixing center in a given quantity via a conveying device, the method further includes: obtaining the real-time weight of the dry powder material in the silo so that the weight of the dry powder material transported to the mixing center is equal to the given quantity of the dry powder material.

4. The dry powder mixing method according to claim 3, characterized in that, The process of obtaining the real-time weight of the dry powder material in the silo, so that the weight of the dry powder material transported to the mixing center is equal to the given amount of dry powder material, specifically involves: The first weight of the dry powder material in the silo before the conveying device transports the dry powder material is obtained; and the second weight of the remaining dry powder material in the silo after the transportation is completed is obtained according to the given amount of dry powder material. The conveying device is controlled to stop transporting the dry powder material when the real-time weight of the dry powder material in the silo is equal to the second weight, so that the weight of the dry powder material transported to the mixing center is equal to the given amount of dry powder material.

5. The dry powder mixing method according to claim 1, characterized in that, The process of spraying the liquid used for mixing with the dry powder material into the mixing center, and using the negative pressure generated by the liquid spray to draw the dry powder material from the conveying device into the mixing center, specifically involves: The liquid used for mixing with the dry powder material is sprayed into the mixing center at a spray pressure of 0.2~1.0MPa, and the dry powder material on the conveying device is sucked into the mixing center by the negative pressure generated by the liquid spray.

6. The dry powder mixing method according to claim 5, characterized in that, During the process of spraying liquid to the mixing center, the angle between the sprayed liquid and the horizontal plane is controlled to be 15~45°.

7. The dry powder mixing method according to claim 1, characterized in that, The step of using a stirring device to stir the materials at the mixing center to ensure that the dry powder material and the liquid are mixed evenly further includes: The materials at the mixing center are stirred using a first impeller with a diameter of 250~350mm at a rotation speed of 0~200r / min; and A second impeller with a diameter of 70~90mm is used to stir the material in the mixing center at a speed of 0~800r / min so that the dry powder material and the liquid are mixed evenly.

8. The dry powder mixing method according to claim 1, characterized in that, The process of transporting the uniformly mixed slurry to the sand mixing truck or the oilfield application unit specifically involves: transporting the uniformly mixed slurry to the sand mixing truck or the oilfield application unit through a closed pipeline; and during the transport of the uniformly mixed slurry to the sand mixing truck or the oilfield application unit, collecting information on the pressure and concentration of the slurry, collecting the transport speed of the slurry, and collecting the real-time feeding speed of the conveying device and the real-time injection flow rate of the liquid.

9. The dry powder mixing method according to claim 8, characterized in that, After the uniformly mixed slurry is transported to the sand mixing truck or the oilfield application unit, the method further includes: controlling the feeding speed of the conveying device, the injection flow rate of the liquid, and the transport speed of the slurry based on the collected slurry pressure and concentration information, the slurry transport speed, the real-time feeding speed of the conveying device, and the real-time injection flow rate of the liquid, so as to control the powder-liquid ratio to be 1%~2%.

10. The dry powder mixing method according to claim 1, characterized in that, The dry powder material is guar gum powder.

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