Natural quartz sand fracturing proppant low water retention sand and its preparation process and device

Abstract

The application provides natural quartz sand fracturing proppant low water retention sand and a preparation process thereof, and adopts a designed natural quartz sand fracturing proppant low water retention sand preparation device, and one or more kinds of chemical substances are used to realize the hydrophobic property of the low water retention sand surface, so that the low water retention sand cannot be agglomerated and caked in the water phase, and the monodispersed natural quartz sand fracturing proppant can be obtained in the water phase, the problem that the natural quartz sand fracturing proppant is easily agglomerated and caked in the water phase is solved, and the problems of pump jamming, abrasion, blockage and the like caused by the low water retention sand in the fracturing process are avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fracturing materials in the oil and gas industry, in particular to a natural quartz sand fracturing proppant low water retention sand and a preparation process and device thereof. BACKGROUND

[0002] With the continuous increase of oil and gas demand at home and abroad, the difficulty of oil and gas exploitation is increasing in the face of high density and low permeability oil and gas reservoirs. Under the new situation of energy structure adjustment, strong demand for oil and gas, and rapid development of technology, how to improve oil and gas production is an important research topic. The use of fracturing technology can effectively develop high density and low permeability oil and gas reservoirs and achieve the goal of improving oil and gas production. In the world, hydraulic fracturing as the main oil and gas development method in recent decades can effectively improve the production of oil and gas wells, and fracturing proppant is a key construction material commonly used in hydraulic fracturing.

[0003] In recent years, quartz sand fracturing proppant has played an important role in the field of oil and gas exploitation due to its low cost and wide source, accounting for 80% to 90% of the total amount of fracturing proppant. Currently, quartz sand fracturing proppant needs to go through a water washing process and a drying process (200℃ to 400℃) in the production process, and can only be used for fracturing after being completely dried. Undried quartz sand fracturing proppant is prone to agglomeration, resulting in caking, which can cause pump sticking, wear, and blockage during fracturing. The use of water washing and drying processes can effectively prevent quartz sand fracturing proppant from agglomerating and caking. However, this process has the disadvantages of being complicated and energy-consuming. In particular, for natural quartz sand fracturing proppant, even if the product is dried using this process, it will re-agglomerate and cake when mixed with water-based fracturing fluid during fracturing, making it difficult to solve the problems of pump sticking, wear, and blockage, and thus unable to be applied in fracturing operations, restricting the further development of hydraulic fracturing and failing to meet the current requirements of oil and gas exploitation and energy demand.

[0004] The existing patent document CN106883837A discloses a hydrophobic modified proppant and its preparation method, and CN115851254A discloses a double hydrophobic modified quartz sand proppant and its preparation method. Both of these technologies are in the category of film-coated proppants, focusing on surface modification. These surface modification technologies use a large amount of modifiers, which are relatively expensive. SUMMARY

[0005] In order to solve the problems in the prior art, the present application provides natural quartz sand fracturing proppant low water retention sand and a preparation process thereof, which can obtain monodisperse natural quartz sand fracturing proppant in an aqueous phase, referred to as "low water retention sand", and solves the problem that natural quartz sand fracturing proppant is prone to agglomeration and caking in an aqueous phase, thereby avoiding problems such as pump jamming, wear and tear, and blockage caused by low water retention sand in the fracturing process. The present application can directly obtain low water retention sand without the need to prepare dry natural quartz sand fracturing proppant, i.e. without the need to use a drying process, thereby achieving the purposes of saving process steps and reducing energy consumption, and without the need to use too many modifiers, thereby reducing costs.

[0006] The present application is implemented by the following technical solutions:

[0007] A preparation process of natural quartz sand fracturing proppant low water retention sand, which is implemented by using a low water retention sand preparation device, wherein the low water retention sand preparation device comprises an upper motor, a rotating shaft, an inner rotating cylinder, an outer rotating cylinder and a lower motor.

[0008] A plurality of adjustable screens are formed in the side wall of the inner rotating cylinder, and a sample inlet is arranged at the top of the inner rotating cylinder; the inner rotating cylinder is coaxially arranged in the outer rotating cylinder; a chemical nozzle is arranged on the outer rotating cylinder and faces the inner rotating cylinder.

[0009] The rotating shaft is connected to the output shaft of the upper motor, and the output shaft of the lower motor is connected to the bottom of the outer rotating cylinder; the upper motor and the lower motor are used to drive the inner rotating cylinder and the outer rotating cylinder to rotate around the axis, respectively.

[0010] The preparation process comprises the following steps:

[0011] (1) The natural quartz sand fracturing proppant is washed with water, and then is added into the inner rotating cylinder through the sample inlet after washing; the upper motor is turned on to drive the inner rotating cylinder to rotate, and the lower motor is turned on to drive the outer rotating cylinder to rotate; the natural quartz sand fracturing proppant can enter the outer rotating cylinder through the adjustable screens.

[0012] (2) The chemical is sprayed to the gap between the inner rotating cylinder and the outer rotating cylinder through the chemical nozzle, and the inner rotating cylinder and the outer rotating cylinder are continuously rotated for 2-8 hours to obtain the natural quartz sand fracturing proppant low water retention sand; wherein the chemical is used to modify the natural quartz sand fracturing proppant, so that the natural quartz sand fracturing proppant has hydrophobicity.

[0013] Preferably, the chemical is one or more of a silane coupling agent, an organic hydrophobic monomer, an organic polymer, a surfactant and an inorganic micro-nano powder.

[0014] Preferably, the mass of the chemical substance accounts for 0.5%-2.5% of the mass of the natural quartz sand fracturing proppant.

[0015] Preferably, the rotating speed of the inner rotating cylinder is 1000-8000r / min, and the rotating speed of the outer rotating cylinder is 1000-6000r / min.

[0016] Preferably, the temperature of the outer rotating cylinder is 20-80℃.

[0017] Preferably, the low water retention sand preparation device further comprises a sample collector arranged on the inner side of the bottom of the outer rotating cylinder.

[0018] Preferably, the chemical substance nozzle is integrated on the sidewall or the inner side of the bottom of the outer rotating cylinder.

[0019] Preferably, the adjustable screen hole is circular, rectangular, oval or polygonal.

[0020] The natural quartz sand fracturing proppant low water retention sand is prepared by the preparation method.

[0021] A natural quartz sand fracturing proppant low water retention sand preparation device comprises an upper motor, a rotating shaft, an inner rotating cylinder, an outer rotating cylinder and a lower motor.

[0022] A plurality of adjustable screen holes are arranged on the sidewall of the inner rotating cylinder, and a sample inlet is arranged on the top of the inner rotating cylinder; the inner rotating cylinder is coaxially arranged in the outer rotating cylinder; a chemical substance nozzle is arranged on the outer rotating cylinder and faces the inner rotating cylinder.

[0023] The top of the inner rotating cylinder is connected with the rotating shaft, and the rotating shaft is connected with the output shaft of the upper motor; the bottom of the outer rotating cylinder is connected with the output shaft of the lower motor; and the upper motor and the lower motor are respectively used for driving the inner rotating cylinder and the outer rotating cylinder to rotate around the axis.

[0024] Compared with the prior art, the present application has the following beneficial effects:

[0025] The application adopts a designed natural quartz sand fracturing proppant low water retention sand preparation device, assists one or more chemicals, realizes the hydrophobic property of the low water retention sand surface, so that the low water retention sand cannot be agglomerated and caked in the water phase, and the monodisperse natural quartz sand fracturing proppant can be obtained in the water phase, the problem that the natural quartz sand fracturing proppant is easily agglomerated and caked in the water phase is solved, and the problems of pump jamming, wear and tear, and blockage generated in the fracturing process of the low water retention sand are avoided. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a natural quartz sand fracturing proppant low water retention sand preparation device schematic diagram of the embodiment 1 of the application (the external rotating cylinder cross section is rectangular);

[0027] Figure 2 is a natural quartz sand fracturing proppant low water retention sand preparation device schematic diagram of the embodiment 2 of the application (the external rotating cylinder cross section is arc-shaped);

[0028] Figure 3 is a natural quartz sand fracturing proppant low water retention sand preparation device schematic diagram of the embodiment 3 of the application (the external rotating cylinder longitudinal section is conical);

[0029] Figure 4 is a natural quartz sand fracturing proppant low water retention sand preparation device schematic diagram of the embodiment 4 of the application (the external rotating cylinder cross section is rectangular, and the sampler is integrated);

[0030] Figure 5 is a natural quartz sand fracturing proppant low water retention sand preparation device schematic diagram of the embodiment 5 of the application (the external rotating cylinder cross section is arc-shaped, and the sampler is integrated);

[0031] Figure 6 is a natural quartz sand fracturing proppant low water retention sand preparation device schematic diagram of the embodiment 6 of the application (the external rotating cylinder cross section is conical, and the sampler is integrated);

[0032] Figure 7 is a natural quartz sand fracturing proppant low water retention sand preparation device schematic diagram of the embodiment 7 of the application (the chemical nozzle is at the middle position of the external rotating cylinder side wall);

[0033] Figure 8 is a natural quartz sand fracturing proppant low water retention sand preparation device schematic diagram of the embodiment 8 of the application (the chemical nozzle is at the bottom position of the external rotating cylinder).

[0034] Wherein, 1-upper motor, 2-rotating shaft, 3-sample inlet, 4-internal rotating cylinder, 5-adjustable screen, 6-chemical nozzle, 7-external rotating cylinder, 8-lower motor, 9-sample collector. DETAILED DESCRIPTION

[0035] In order to make the personnel in the technical field better understand the application scheme, the technical scheme in the embodiments of the application will be clearly and completely described below in combination with the drawings in the embodiments of the application. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor should belong to the protection scope of the application.

[0036] It should be noted that the terms "first", "second" and the like in the specification and claims of the application and the above-described drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or a chronological sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0037] The application will be further described in detail below in combination with specific embodiments, which are an explanation of the application rather than a limitation.

[0038] The natural quartz sand fracturing proppant low water retention sand preparation process is: using natural quartz sand fracturing proppant as raw material, monodisperse natural quartz sand fracturing proppant can be obtained in aqueous phase, which is referred to as "low water retention sand". After the natural quartz sand fracturing proppant is subjected to the water washing process, it does not need to be subjected to the drying process, but directly enters the modification process. By using the designed natural quartz sand fracturing proppant low water retention sand preparation device, one or more kinds of chemicals are assisted, including silane coupling agent, organic hydrophobic monomer, organic polymer, surfactant and inorganic micro-nano powder, the low water retention sand is endowed with hydrophobic property on the surface, so that it cannot be agglomerated and caked in the aqueous phase, and the low water retention sand can be directly used to complete the fracturing operation, avoiding the problems of pump jamming, wear and blockage generated in the fracturing process.

[0039] The natural quartz sand fracturing proppant is used as raw material, after the water washing process, it does not need to be subjected to the drying process, but can directly enter the modification process.

[0040] The water washing process refers to removing the surface attachments of natural quartz sand fracturing proppant, including inorganic salts, oxides, organic matter, etc., by the flushing and dissolving effect of water, so that the surface is clean.

[0041] The modification process uses a natural quartz sand fracturing proppant low water retention sand preparation device and one or more auxiliary chemicals to impart hydrophobic properties to the surface of the low water retention sand.

[0042] The natural quartz sand fracturing proppant low water retention sand preparation device has the function of automatically modifying low water retention sand, and its structure includes an upper motor 1, a rotating shaft 2, a sample inlet 3, an internal rotating cylinder 4, an adjustable screen hole 5, a chemical nozzle 6, an external rotating cylinder 7, a lower motor 8, and a sample collector 9.

[0043] The internal rotating cylinder 4 has a plurality of adjustable screen holes 5 on its side wall, and the top of the internal rotating cylinder 4 is provided with a sample inlet 3; the upper motor 1 provides horizontal rotating power for the internal rotating cylinder 4; the lower motor 8 provides horizontal rotating power for the external rotating cylinder 7; the internal rotating cylinder 4 is inside the external rotating cylinder 7; the internal rotating cylinder 7 is integrated with a heating coil or component, which can provide constant temperature for the external rotating cylinder, with a temperature range of 20℃-80℃.

[0044] The chemical nozzle 6 is integrated on the side wall of the external rotating cylinder 7, and its position is adjustable, ranging from the upper edge to the lower edge of the side wall of the external rotating cylinder 7, or it can also be integrated at the bottom of the external rotating cylinder 7; the direction of the chemical nozzle 6 points to the inside of the external rotating cylinder 7, and the angle is adjustable, ranging from 10° to 80°. The aperture of the adjustable screen hole 6 is selected according to the specifications of the natural quartz sand fracturing proppant.

[0045] The one or more auxiliary chemicals refer to one or more chemicals that can impart hydrophobic properties to the surface of the low water retention sand. The chemicals have hydrophobic properties or have hydrophobic properties after chemical reaction.

[0046] The low water retention sand refers to single dispersed particles that do not agglomerate or clump in water after the modification process.

[0047] The water phase includes water, aqueous solution, fracturing fluid, and composite water phase system, etc.

[0048] The application provides natural quartz sand fracturing proppant low water retention sand and a preparation process thereof, and can obtain monodisperse natural quartz sand fracturing proppant, namely low water retention sand, in an aqueous phase, solves the problem that natural quartz sand fracturing proppant is easy to agglomerate and cake in the aqueous phase, and thus avoids pump sticking, wear, blockage and the like caused by low water retention sand in the fracturing process. The application can directly obtain low water retention sand, and does not need to prepare dry natural quartz sand fracturing proppant, that is, does not need to use a drying process, and thus saves process steps and reduces energy consumption. The application uses a designed natural quartz sand fracturing proppant low water retention sand preparation device, and assists one or more chemicals, including a silane coupling agent, an organic hydrophobic monomer, an organic polymer, a surfactant and inorganic micro-nano powder, to realize the hydrophobic property of the low water retention sand surface, so that the low water retention sand cannot agglomerate and cake in the aqueous phase. The aqueous phase covered by the application includes water, an aqueous solution, a fracturing fluid and a composite aqueous phase system and the like. The application has the advantages of simple operation and easy realization, and is conducive to popularization in the fracturing field of the oil and gas industry, and has a wide application prospect.

[0049] Specifically, the modification process, using a natural quartz sand fracturing proppant low water retention sand preparation device and assisted by one or more chemicals, serves to impart hydrophobic properties to the surface of the low water retention sand, involving a temperature condition range of 20℃-80℃. The natural quartz sand fracturing proppant low water retention sand preparation device refers to a function of automatically modifying low water retention sand, and the structure includes a motor, a rotating shaft, a sample inlet, an internal rotating cylinder, an adjustable sieve, a chemical nozzle, an external rotating cylinder, and a sample collector. The motor includes an upper motor and a lower motor. The upper motor drives the rotating shaft, which in turn drives the internal rotating cylinder to generate centrifugal force to enable the natural quartz sand fracturing proppant to pass through the adjustable sieve in the form of monodisperse particles. The monodisperse particles enter the external rotating cylinder, and the lower motor drives the external rotating cylinder to make the monodisperse particles perform circular motion with the external rotating cylinder. At the same time, the chemical nozzle sprays one or more chemicals towards the monodisperse particles and the external rotating cylinder. After a certain period of time, the monodisperse particles complete the modification. The lower motor is used to adjust the speed of the external rotating cylinder, which can accelerate or decelerate the speed of the external rotating cylinder. After the monodisperse particles complete the modification, the motor is stopped, and the finished product is collected in the sample collector. The speed of the internal rotating cylinder ranges from 1000 to 8000 r / min. The speed of the external rotating cylinder ranges from 1000 to 6000 r / min. The aperture of the adjustable sieve is selected according to the specifications of the natural quartz sand fracturing proppant. The adjustable sieve can be circular, rectangular, oval, or polygonal. The one or more chemicals assisted by the modification process have hydrophobic properties or hydrophobic properties after chemical reactions, and include silane coupling agents, organic hydrophobic monomers, organic polymers, surfactants, and inorganic micro-nano powders. The amount of the one or more chemicals is 0.5% to 2.5% based on the mass fraction of the natural quartz sand fracturing proppant. The one or more chemicals are sprayed in the form of liquid droplets on the surface of the monodisperse particles through the chemical nozzle. The chemical nozzle sprays the chemicals on the surface of the monodisperse particles using air pressure or water pressure.

[0050] The present application provides a natural quartz sand fracturing proppant low water retention sand preparation process, which includes the following steps:

[0051] (1) A certain amount of natural quartz sand fracturing proppant is washed with water, and then placed in the natural quartz sand fracturing proppant low water retention sand preparation device through the sample inlet. The upper motor is turned on to rotate the internal rotating cylinder at a speed of 1000-8000 r / min, and the lower motor is turned on to rotate the external rotating cylinder at a speed of 1000-6000 r / min.

[0052] (2) One or more chemical substances, such as silane coupling agents, organic hydrophobic monomers, organic polymers, surfactants or inorganic micro-nano powders, are sprayed through chemical substance nozzles onto the monodisperse particles that are moving in a circular motion. The temperature of the external rotating cylinder is set to 20℃~80℃, and the internal and external rotating cylinders are kept rotating continuously for 2~8h. Then the upper and lower motors are turned off, and the modified monodisperse particles fall into the natural quartz sand fracturing proppant low water holding sand preparation device or sample collector to collect the finished product.

[0053] Example

[0054] This invention provides multiple embodiments to further explain and illustrate the preparation process of low water-holding sand for natural quartz sand fracturing proppant, the products thereof, and the beneficial effects thereof.

[0055] Examples 1-8 control a single variable: the silane coupling agent KH570 is used at a dosage of 2.0 g / L, which remains constant; the change is in the preparation device for the low water-holding capacity sand of the natural quartz sand fracturing proppant. These examples illustrate that the preparation device for the low water-holding capacity sand of the natural quartz sand fracturing proppant has adjustability and selectability.

[0056] Example 1

[0057] Weigh 10 kg of natural quartz sand fracturing proppant, and after a water washing process, place it into a low water-holding sand preparation device for natural quartz sand fracturing proppant through the injection port. Figure 1 The outer rotating cylinder (with a rectangular cross-section) was used. The upper motor was turned on to rotate the inner rotating cylinder at 6000 r / min, and the lower motor was turned on to rotate the outer rotating cylinder at 4000 r / min. The prepared silane coupling agent KH570, at a dosage of 2.0 g / L, was sprayed through a chemical nozzle onto the circularly moving monodisperse particles. The temperature of the outer rotating cylinder was set to 20℃, and both the inner and outer rotating cylinders were kept rotating continuously for 4 hours. Then, the upper and lower motors were turned off, and the modified monodisperse particles were allowed to fall into the natural quartz sand fracturing proppant low water-holding sand preparation device, and the finished product was collected. The performance results of the obtained samples are shown in Table 1.

[0058] Example 2

[0059] The difference between this embodiment and Embodiment 2 is that the external rotating cylinder of the natural quartz sand fracturing proppant low water-holding sand preparation device has an arc-shaped cross-section, such as... Figure 2 As shown in the figure. The performance results of the obtained samples are shown in Table 1.

[0060] Example 3

[0061] The difference between this embodiment and Embodiment 1 is that the external rotating cylinder of the natural quartz sand fracturing proppant low water-holding sand preparation device has a conical longitudinal section, such as...Figure 3 The sample performance results are shown in Table 1.

[0062] Example 4

[0063] The difference between this example and Example 1 is that the cross section of the outer rotating cylinder of the natural quartz sand fracturing proppant low water retention sand preparation device is rectangular, and the integrated sample collector is shown in Figure 4 The sample performance results are shown in Table 1.

[0064] Example 5

[0065] The difference between this example and Example 1 is that the cross section of the outer rotating cylinder of the natural quartz sand fracturing proppant low water retention sand preparation device is arc-shaped, and the integrated sample collector is shown in Figure 5 The sample performance results are shown in Table 1.

[0066] Example 6

[0067] The difference between this example and Example 1 is that the longitudinal section of the outer rotating cylinder of the natural quartz sand fracturing proppant low water retention sand preparation device is conical, and the integrated sample collector is shown in Figure 6 The sample performance results are shown in Table 1.

[0068] Example 7

[0069] The difference between this example and Example 1 is that the chemical nozzle of the natural quartz sand fracturing proppant low water retention sand preparation device is at the middle position of the side wall of the outer rotating cylinder, as shown in Figure 7 The sample performance results are shown in Table 1.

[0070] Example 8

[0071] The difference between this example and Example 1 is that the chemical nozzle of the natural quartz sand fracturing proppant low water retention sand preparation device is at the bottom position of the outer rotating cylinder, as shown in Figure 8 The sample performance results are shown in Table 1.

[0072] Table 1 Sample performance results of Examples 1-8

[0073] Example 1 2 3 4 5 6 7 8 Agglomeration, caking No No No No No No No No

[0074] From Examples 1-8, it can be seen that by changing and adjusting the natural quartz sand fracturing proppant low water retention sand preparation device, the sample can effectively avoid sample agglomeration and caking, which shows that the natural quartz sand fracturing proppant low water retention sand preparation device has adjustability and selectability.

[0075] Examples 1, 9-12 are single variable control: using silane coupling agent KH570, the natural quartz sand fracturing proppant low water retention sand preparation device is shown in Figure 1, the amount of chemical substance is 2.0 g / L, which remains unchanged; the change is the amount of KH570, which is 2.0 g / L, 0.5 g / L, 1.0 g / L, 1.5 g / L, and 2.5 g / L, respectively. The examples show that the amount of chemical substance has an effect on the performance of the sample.

[0076] Example 9

[0077] The difference between this example and Example 1 is that the amount of KH570 is 0.5 g / L. The performance results of the obtained sample are shown in Table 2.

[0078] Example 10

[0079] The difference between this example and Example 1 is that the amount of KH570 is 1.0 g / L. The performance results of the obtained sample are shown in Table 2.

[0080] Example 11

[0081] The difference between this example and Example 1 is that the amount of KH570 is 1.5 g / L. The performance results of the obtained sample are shown in Table 2.

[0082] Example 12

[0083] The difference between this example and Example 1 is that the amount of KH570 is 2.5 g / L. The performance results of the obtained sample are shown in Table 2.

[0084] Table 2 Performance results of samples of Examples 1, 9-12

[0085] Example 1 9 10 11 12 Agglomeration, caking No Yes Yes Partly No

[0086] As can be seen from Examples 1, 9-12, when the amount of KH570 is small, the sample is prone to agglomeration and caking, and when the amount reaches 2.0 g / L, the sample does not agglomerate or cake. Considering economy, the optimal amount is 2.0 g / L. The results show that the amount of KH570 has a significant effect on whether the sample agglomerates or cakes, and further silane coupling agents and chemical substances can have a significant effect on the performance of the sample.

[0087] Examples 1, 13-16 are control single variables: the preparation device of the natural quartz sand fracturing proppant low water retention sand is as shown in Figure 1 The amount of chemical substance is 2.0 g / L, which remains unchanged; the change is the type of chemical substance, which is KH570, dopamine, polyvinyl alcohol, F127, and micro-nano silicon dioxide, respectively. The examples show the effect of selecting a hydrophobic and oleophilic chemical substance on the performance of the sample.

[0088] Example 13

[0089] The difference between this example and Example 1 is that the type of chemical substance is dopamine. The performance results of the obtained sample are shown in Table 3.

[0090] Example 14

[0091] The difference between this example and Example 1 is that the chemical species is polyvinyl alcohol. The performance results of the obtained sample are shown in Table 3.

[0092] Example 15

[0093] The difference between this example and Example 1 is that the chemical species is F127. The performance results of the obtained sample are shown in Table 3.

[0094] Example 16

[0095] The difference between this example and Example 1 is that the chemical species is micro-nano silicon dioxide. The performance results of the obtained sample are shown in Table 3.

[0096] Table 3 Performance results of samples of Examples 1, 13-16

[0097] Example 1 13 14 15 16 Agglomeration, caking No No No No No

[0098] As can be seen from Examples 1, 13-16, by using a hydrophobic and oleophilic chemical species, even if the chemical species is changed, the sample can effectively avoid sample agglomeration and caking.

[0099] Examples 1, 17-19 are to control a single variable: the preparation device of the natural quartz sand fracturing proppant low water retention sand is as shown in Figure 1 , the amount of KH570 is 2.0 g / L, which remains unchanged; the change is the reaction temperature, which is 20°C, 40°C, 60°C, and 80°C, respectively, to illustrate the effect of temperature on the preparation process through the examples.

[0100] Example 17

[0101] The difference between this example and Example 1 is that the reaction temperature is 40°C. The performance results of the obtained sample and the process effect are shown in Table 4.

[0102] Example 18

[0103] The difference between this example and Example 1 is that the reaction temperature is 60°C. The performance results of the obtained sample and the process effect are shown in Table 4.

[0104] Example 19

[0105] The difference between this example and Example 1 is that the reaction temperature is 80°C. The performance results of the obtained sample and the process effect are shown in Table 4.

[0106] Table 4 Performance results of samples of Examples 1, 17-19 and process effects

[0107] Example 1 17 18 19 Agglomeration, caking No No No No Reaction time (h) 4 3.2 2.8 2.4 Energy consumption No No Generally Yes

[0108] As can be seen from Examples 1 and 17-19, increasing the reaction temperature can accelerate the reaction rate, but it is easy to consume energy. Although increasing the reaction temperature can effectively prevent the sample from agglomerating and clumping, the reaction temperature needs to be selected according to the actual production.

[0109] Examples 20-23 are examples of changes in the rotational speed of the inner and outer rotating cylinders.

[0110] Example 20

[0111] Weigh 10 kg of natural quartz sand fracturing proppant, and after a water washing process, place it into a low water-holding sand preparation device for natural quartz sand fracturing proppant through the injection port. Figure 1 The outer rotating cylinder (with a rectangular cross-section) was used. The upper motor was turned on to rotate the inner rotating cylinder at 5200 r / min, and the lower motor was turned on to rotate the outer rotating cylinder at 3000 r / min. The prepared silane coupling agent KH570, at a dosage of 2.0 g / L, was sprayed through a chemical nozzle onto the circularly moving monodisperse particles. The temperature of the outer rotating cylinder was set to 20℃, and both the inner and outer rotating cylinders were kept rotating continuously for 4 hours. Then, the upper and lower motors were turned off, and the modified monodisperse particles were allowed to fall into the natural quartz sand fracturing proppant low water-holding sand preparation device, and the finished product was collected. The performance results and process effects of the obtained samples are shown in Table 5.

[0112] Example 21

[0113] The difference between this embodiment and Embodiment 20 is that the internal rotating cylinder rotates at a speed of 4700 r / min, while the external rotating cylinder rotates at a speed of 1550 r / min. The performance results of the obtained samples and the effects of the process are shown in Table 5.

[0114] Example 22

[0115] The difference between this embodiment and Embodiment 20 is that the internal rotating cylinder rotates at a speed of 3920 r / min, while the external rotating cylinder rotates at a speed of 1310 r / min. The performance results of the obtained samples and the effects of the process are shown in Table 5.

[0116] Example 23

[0117] The difference between this embodiment and Embodiment 20 is that the internal rotating cylinder rotates at a speed of 2350 r / min, while the external rotating cylinder rotates at a speed of 1200 r / min. The performance results of the obtained samples and the effects of the process are shown in Table 5.

[0118] Table 5 Performance results and process effects of samples 20-23 in Examples 20-23

[0119] Example 1 20 21 22 Agglomeration, caking No No No No Reaction time (h) 4.6 5.0 5.7 7.5 Energy consumption No Generally Yes Yes

[0120] From the examples 20-23, it can be seen that by reducing the rotating speed of the inner rotating cylinder and the outer rotating cylinder, the sample can effectively avoid sample agglomeration and caking, prolong the reaction time, and improve the energy consumption to a certain extent, and the appropriate rotating speed needs to be selected according to the actual production.

[0121] It can be seen from the comparison of the above example results that the natural quartz sand fracturing proppant low water holding rate sand preparation process and the product provided by the application can effectively avoid sample agglomeration and caking, thereby avoiding pump sticking, wear, blockage and the like generated in the fracturing process. Since the drying process is not required, the purposes of saving process steps and reducing energy consumption are achieved, and the whole has the advantages of simple operation and easy implementation, and can be popularized and applied in the fracturing material field of the oil and gas industry.

[0122] In order to achieve the above-mentioned purposes, the main technical means adopted in the application is as follows. It is necessary to clearly, completely and accurately describe, and to illustrate the essential content of the application. The degree of disclosure is that the ordinary skilled person in the art can understand and implement.

Claims

1. A process for the production of a natural quartz sand frac proppant low water retention sand, characterized in that, The process is realized by a low water holding sand preparation device, which comprises an upper motor (1), a rotating shaft (2), an inner rotating cylinder (4), an outer rotating cylinder (7) and a lower motor (8). A plurality of adjustable sieves (5) are arranged on the sidewall of the inner rotating cylinder (4), and a sample inlet (3) is arranged on the top of the inner rotating cylinder (4); the inner rotating cylinder (4) is coaxially arranged in the outer rotating cylinder (7); a chemical nozzle (6) is arranged on the outer rotating cylinder (7) and faces the inner rotating cylinder (4). The top of the inner rotating cylinder (4) is connected with the rotating shaft (2), and the rotating shaft (2) is connected with the output shaft of the upper motor (1); the bottom of the outer rotating cylinder (7) is connected with the output shaft of the lower motor (8); the upper motor (1) and the lower motor (8) are used for driving the inner rotating cylinder (4) and the outer rotating cylinder (7) to rotate around the axis, respectively. The preparation process comprises: S1. washing the natural quartz sand fracturing proppant, adding the natural quartz sand fracturing proppant into the inner rotating cylinder (4) from the sample inlet (3) after washing, starting the upper motor (1) to make the inner rotating cylinder (4) rotate, and starting the lower motor (8) to make the outer rotating cylinder (7) rotate; the natural quartz sand fracturing proppant can enter the outer rotating cylinder (7) through the adjustable sieves (5); S2. spraying the chemical substance to the gap between the inner rotating cylinder (4) and the outer rotating cylinder (7) through the chemical nozzle, keeping the inner rotating cylinder (4) and the outer rotating cylinder (7) continuously rotating for 2-8 h to obtain the natural quartz sand fracturing proppant low water holding sand; wherein the chemical substance is used for modifying the natural quartz sand fracturing proppant, so that the natural quartz sand fracturing proppant has hydrophobicity.

2. The natural quartz sand frac proppant low water retention sand production process of claim 1 wherein, The chemical substance is one or more of a silane coupling agent, an organic hydrophobic monomer, an organic polymer, a surfactant and an inorganic micro-nano powder.

3. The natural quartz sand frac proppant low water retention sand production process of claim 1 wherein, The mass of the chemical substance accounts for 0.5%-2.5% of the mass of the natural quartz sand fracturing proppant.

4. The natural quartz sand frac proppant low water retention sand production process of claim 1 wherein, The rotating speed of the inner rotating cylinder (4) is 1000-8000 r / min, and the rotating speed of the outer rotating cylinder (7) is 1000-6000 r / min.

5. The natural quartz sand frac proppant low water retention sand production process of claim 1 wherein, The temperature of the outer rotating cylinder (7) is 20-80 ℃.

6. The natural quartz sand frac proppant low water retention sand production process of claim 1 wherein, The low water holding sand preparation device further comprises a sample collector (9) arranged on the inner side of the bottom of the outer rotating cylinder (7).

7. The natural quartz sand frac proppant low water retention sand production process of claim 1 wherein, The chemical nozzle (6) is integrated on the sidewall or the inner side of the bottom of the outer rotating cylinder (7).

8. The natural quartz sand frac proppant low water retention sand production process of claim 1 wherein, The shape of the adjustable sieves is circular, rectangular, oval or polygonal.

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