Natural quartz sand fracturing propping agent sand with low water holding capacity as well as preparation process and device of natural quartz sand fracturing propping agent sand

Abstract

According to the natural quartz sand fracturing propping agent low-water-holding-rate sand and the preparation technology thereof, a designed natural quartz sand fracturing propping agent low-water-holding-rate sand preparation device is adopted, one or more chemical substances are assisted, the surface hydrophobic property of the low-water-holding-rate sand is achieved, the low-water-holding-rate sand cannot be agglomerated and caked in a water phase, and the low-water-holding-rate sand is prepared. The monodisperse natural quartz sand fracturing propping agent can be obtained in a water phase, and the problem that the natural quartz sand fracturing propping agent is easy to agglomerate and cake in the water phase is solved, so that pump blockage, abrasion, blockage and the like generated in the fracturing process of low-water-holding-rate sand are avoided.

Description

Technical Field

[0001] The invention relates to the field of fracturing materials for the petroleum and natural gas industries, in particular to natural quartz sand fracturing proppant low water holding rate sand and a preparation process and device thereof. Background Art

[0002] With the continuous increase in demand for oil and gas at home and abroad, the difficulty of oil and gas extraction 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 technological development, how to increase 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 increasing oil and gas production. Globally, hydraulic fracturing, as the main oil and gas development method in recent decades, can effectively increase the production of oil and gas wells. Fracturing proppants are key construction materials commonly used in hydraulic fracturing.

[0003] In recent years, quartz sand fracturing proppants have low cost and wide sources, and their usage accounts for 80% to 90% of the total usage of fracturing proppants, playing an important role in the field of oil and gas extraction. At present, during the production process, quartz sand fracturing proppants need to go through a water washing process and a drying process (200℃ to 400℃), and can only be put into fracturing after they are completely dried. Because the undried quartz sand fracturing proppants are prone to agglomeration, resulting in agglomeration, which causes problems such as pump jam, wear, and blockage during the fracturing process. The use of water washing and drying processes can effectively prevent the agglomeration and agglomeration of quartz sand fracturing proppants. However, this process has the disadvantages of cumbersome steps and high energy consumption. Especially for natural quartz sand fracturing proppants, even if this process is used to obtain a dry product, the product will re-agglomerate and agglomerate when it is combined with the aqueous fracturing fluid during the fracturing process, making it difficult to solve the problems of pump jam, wear, and blockage, which in turn makes it impossible to use it in fracturing operations, restricting the further development of hydraulic fracturing, and making it difficult to meet the existing oil and gas extraction requirements and energy needs.

[0004] Existing patent document CN106883837A discloses a hydrophobic modified proppant and a preparation method thereof, and CN115851254A discloses an amphiphobic modified quartz sand proppant and a preparation method thereof. Both technologies belong to the category of coated proppant and focus on surface modification. These surface modification technologies use a large amount of modifiers and are relatively costly. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides natural quartz sand fracturing proppant low water holding rate sand and its preparation process, which can obtain monodisperse natural quartz sand fracturing proppant in water phase, referred to as "low water holding rate sand", and solve the problem that natural quartz sand fracturing proppant is easy to agglomerate and agglomerate in water phase, thereby avoiding the problems of pump jamming, wear, blockage, etc. caused by low water holding rate sand in the fracturing process. The present invention can directly obtain low water holding rate sand without preparing dry natural quartz sand fracturing proppant, that is, without using drying process, thus achieving the purpose of saving process steps and reducing energy consumption, and without using too much modifier, thus reducing cost.

[0006] The present invention is achieved through the following technical solutions:

[0007] A process for preparing low water-holding sand for natural quartz sand fracturing proppant, the method is implemented by a low water-holding sand preparation device, the low water-holding sand preparation device comprising: an upper motor, a rotating shaft, an inner rotating cylinder, an outer rotating cylinder and a lower motor;

[0008] The side wall of the inner rotating cylinder is provided with a plurality of adjustable sieve holes, and the top of the inner rotating cylinder is provided with a sample inlet; the inner rotating cylinder is coaxially placed in the outer rotating cylinder; the outer rotating cylinder is provided with a chemical substance nozzle, and the chemical substance nozzle faces the inner rotating cylinder;

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

[0010] The preparation process comprises:

[0011] (1) washing the natural quartz sand fracturing proppant with water, adding the washed proppant into the inner rotating cylinder from the injection port, turning on the upper motor to rotate the inner rotating cylinder, and turning on the lower motor to rotate the outer rotating cylinder; the natural quartz sand fracturing proppant can enter the outer rotating cylinder from the adjustable sieve hole;

[0012] (2) Spraying the chemical substance into the gap between the inner rotating cylinder and the outer rotating cylinder through a chemical substance nozzle, and keeping the inner rotating cylinder and the outer rotating cylinder rotating continuously for 2 to 8 hours, to obtain natural quartz sand fracturing proppant with low water holding rate sand; wherein the chemical substance is used to modify the natural quartz sand fracturing proppant to make the natural quartz sand fracturing proppant hydrophobic.

[0013] Preferably, 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.

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

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

[0016] Preferably, the temperature of the external rotating drum is 20°C to 80°C.

[0017] Preferably, the low water holding rate sand preparation device further comprises a sample collector, and the sample collector is arranged on the inner side of the bottom of the external rotating cylinder.

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

[0019] Preferably, the adjustable sieve holes are in a circular, rectangular, elliptical or polygonal shape.

[0020] The natural quartz sand fracturing proppant low water holding rate sand is obtained by the preparation method.

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

[0022] The side wall of the inner rotating cylinder is provided with a plurality of adjustable sieve holes, and the top of the inner rotating cylinder is provided with a sample inlet; the inner rotating cylinder is coaxially placed in the outer rotating cylinder; the outer rotating cylinder is provided with a chemical substance nozzle, and the chemical substance nozzle faces the inner rotating cylinder;

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

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

[0025] The present invention adopts a designed natural quartz sand fracturing proppant low water holding rate sand preparation device, and assists one or more chemical substances to achieve the hydrophobic property of the low water holding rate sand surface, so that it can not agglomerate and agglomerate in the water phase, and can obtain a monodisperse natural quartz sand fracturing proppant in the water phase, which solves the problem that the natural quartz sand fracturing proppant is easy to agglomerate and agglomerate in the water phase, thereby avoiding the pump jam, wear, blockage, etc. caused by the low water holding rate sand in the fracturing process. The present invention can directly obtain low water holding rate sand without preparing dry natural quartz sand fracturing proppant, that is, without using a drying process, achieving the purpose of saving process steps and reducing energy consumption; and without using too much modifier, reducing costs. The present invention as a whole has the advantages of simple operation and easy implementation, which is conducive to promotion in the field of fracturing in the oil and gas industry and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of a natural quartz sand fracturing proppant low water retention sand preparation device according to Example 1 of the present invention (the cross section of the external rotating cylinder is a rectangle);

[0027] Figure 2 Schematic diagram of a natural quartz sand fracturing proppant low water retention sand preparation device according to Example 2 of the present invention (the cross section of the external rotating cylinder is arc-shaped);

[0028] Figure 3 Schematic diagram of a natural quartz sand fracturing proppant low water retention sand preparation device according to Example 3 of the present invention (the longitudinal section of the external rotating cylinder is conical);

[0029] Figure 4 Schematic diagram of a natural quartz sand fracturing proppant low water retention sand preparation device according to Example 4 of the present invention (the cross section of the external rotating cylinder is rectangular, and a sample collector is integrated);

[0030] Figure 5 Schematic diagram of a natural quartz sand fracturing proppant low water retention sand preparation device according to Example 5 of the present invention (the cross section of the external rotating cylinder is arc-shaped, and a sample collector is integrated);

[0031] Figure 6 Schematic diagram of a natural quartz sand fracturing proppant low water retention sand preparation device according to Example 6 of the present invention (the cross section of the external rotating cylinder is conical, and a sample collector is integrated);

[0032] Figure 7 Schematic diagram of a natural quartz sand fracturing proppant low water retention sand preparation device according to Example 7 of the present invention (the chemical substance nozzle is located in the middle of the side wall of the external rotating cylinder);

[0033] Figure 8 This is a schematic diagram of a natural quartz sand fracturing proppant low water retention sand preparation device according to Example 8 of the present invention (the chemical substance nozzle is located at the bottom of the external rotating cylinder).

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

[0035] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0036] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0037] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0038] The preparation process of natural quartz sand fracturing proppant low water-holding sand of the present invention is as follows: natural quartz sand fracturing proppant is used as raw material to obtain monodisperse natural quartz sand fracturing proppant in water phase, referred to as "low water-holding sand", after the natural quartz sand fracturing proppant is subjected to a water washing process, it does not need to be subjected to a drying process, and directly enters a modification process, and a designed natural quartz sand fracturing proppant low water-holding sand preparation device is used to assist with one or more chemical substances, including silane coupling agent, organic hydrophobic monomer, organic polymer, surfactant and inorganic micro-nano powder, so as to give the low water-holding sand surface hydrophobic properties, so that the low water-holding sand will not agglomerate and agglomerate in the water phase, and the low water-holding sand can be directly used to complete the fracturing operation, thereby avoiding the problems of pump jamming, wear, blockage and the like generated during the fracturing process.

[0039] The natural quartz sand fracturing proppant is used as a raw material and can directly enter the modification process without the need for a drying process after undergoing a water washing process.

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

[0041] The modification process uses a natural quartz sand fracturing proppant low water holding rate sand preparation device and one or more auxiliary chemical substances to achieve the purpose of giving the low water holding rate sand surface hydrophobic properties.

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

[0043] A plurality of adjustable sieve holes 5 are provided on the side wall of the internal rotating cylinder 4, and a sample inlet 3 is provided on the top of the internal rotating cylinder 4; the upper motor 1 provides horizontal rotation power for the internal rotating cylinder 4; the lower motor 8 provides horizontal rotation power for the external rotating cylinder 7; the internal rotating cylinder 4 is inside the external rotating cylinder 7; a heating coil or component is integrated inside the external rotating cylinder 7 to provide a constant temperature for the external rotating cylinder, and the temperature range is 20°C to 80°C.

[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. 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 sieve hole 6 is selected according to the specifications of the natural quartz sand fracturing proppant.

[0045] The auxiliary one or more chemical substances refer to one or more chemical substances that can impart hydrophobicity to the surface of the low water holding rate sand, and the chemical substances have hydrophobicity or have hydrophobicity after chemical reaction.

[0046] The low water holding rate sand refers to monodisperse particles that do not agglomerate or clump in the water phase after the modification process.

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

[0048] The present invention provides a natural quartz sand fracturing proppant low water holding rate sand and a preparation process thereof, and can obtain a monodisperse natural quartz sand fracturing proppant in an aqueous phase, referred to as "low water holding rate sand", which solves the problem that the natural quartz sand fracturing proppant is easy to agglomerate and agglomerate in the aqueous phase, thereby avoiding the pump jam, wear, blockage, etc. caused by the low water holding rate sand in the fracturing process. The present invention can directly obtain low water holding rate sand without the need to prepare dry natural quartz sand fracturing proppant, that is, without the need to use a drying process, thereby achieving the purpose of saving process steps and reducing energy consumption. The present invention adopts a designed natural quartz sand fracturing proppant low water holding rate sand preparation device, assisted by one or more chemical substances, including silane coupling agents, organic hydrophobic monomers, organic polymers, surfactants and inorganic micro-nano powders, to achieve the hydrophobic properties of the surface of the low water holding rate sand, so that it can not agglomerate and agglomerate in the aqueous phase. The aqueous phase covered by the present invention includes clean water, aqueous solution, fracturing fluid and composite aqueous phase system. The invention as a whole has the advantages of simple operation and easy realization, is conducive to promotion in the field of oil and gas industry fracturing, and has broad application prospects.

[0049] Specifically, the modification process uses a natural quartz sand fracturing proppant low water retention sand preparation device and one or more auxiliary chemical substances to impart hydrophobic properties to the surface of the low water retention sand, and the temperature conditions involved range from 20°C to 80°C. The natural quartz sand fracturing proppant low water-holding sand preparation device refers to a device with the function of automatically modifying low water-holding sand, and the structure includes a motor, a rotating shaft, an injection port, an internal rotating cylinder, an adjustable sieve hole, a chemical substance 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, the rotating shaft transmits the transmission to the internal rotating cylinder, the internal rotating cylinder generates centrifugal force to enable the natural quartz sand fracturing proppant to pass through the adjustable sieve hole as monodisperse particles; the monodisperse particles enter the external rotating cylinder, and the lower motor drives the external rotating cylinder at the same time, so that the monodisperse particles and the external rotating cylinder perform circular motion; at the same time, the chemical substance nozzle sprays one or more chemical substances onto the monodisperse particles and the external rotating cylinder, and after a certain period of time, the monodisperse particles are modified; the rotation speed of the external rotating cylinder is adjusted by the lower motor, and the rotation speed of the external rotating cylinder can be accelerated or decelerated. After all the monodisperse particles are modified, the motor is stopped and the finished products are collected in the sample collector. The speed range of the inner rotating drum is 1000-8000r / min; the speed range of the outer rotating drum is 1000-6000r / min; the aperture of the adjustable sieve hole is selected according to the specifications of the natural quartz sand fracturing proppant; the shape of the adjustable sieve hole is circular, rectangular, elliptical and polygonal; the one or more auxiliary chemical substances refer to those having hydrophobic properties or having hydrophobic properties after chemical reaction, including silane coupling agents, organic hydrophobic monomers, organic polymers, surfactants and inorganic micro-nano powders; the one or more auxiliary chemical substances are calculated by the mass fraction of the natural quartz sand fracturing proppant, and their dosage is 0.5%-2.5%; the one or more auxiliary chemical substances are evenly sprayed on the surface of monodisperse particles in the form of small liquid droplets through a chemical substance nozzle; the chemical substance nozzle uses air pressure or water pressure to spray the chemical substances on the surface of monodisperse particles.

[0050] The present invention provides a process for preparing natural quartz sand fracturing proppant low water holding rate sand, comprising the following steps:

[0051] (1) After a certain amount of natural quartz sand fracturing proppant is washed with water, it is placed in a natural quartz sand fracturing proppant low water holdup sand preparation device through an injection port, the upper motor is turned on to rotate the inner rotating cylinder at a speed of 1000 to 8000 r / min, and the lower motor is turned on to rotate the outer rotating cylinder at a speed of 1000 to 6000 r / min;

[0052] (2) One or more prepared chemical substances, such as silane coupling agent, organic hydrophobic monomer, organic polymer, surfactant or inorganic micro-nano powder, are sprayed onto the monodisperse particles in circular motion through a chemical substance nozzle, the temperature of the external rotating cylinder is set to 20°C to 80°C, and the internal rotating cylinder and the external rotating cylinder are kept rotating for 2 to 8 hours; then the upper motor and the lower motor are turned off, and all the modified monodisperse particles fall on the natural quartz sand fracturing proppant low water retention sand preparation device or sample collector, and the finished product is collected.

[0053] Example

[0054] The present invention further explains and illustrates the natural quartz sand fracturing proppant low water holding rate sand preparation process and its products as well as the beneficial effects brought by the present invention by providing multiple embodiments.

[0055] Examples 1 to 8 control a single variable: the silane coupling agent KH570 is used in an amount of 2.0 g / L and remains unchanged; what is changed is the natural quartz sand fracturing proppant low water retention sand preparation device. The examples illustrate that the natural quartz sand fracturing proppant low water retention sand preparation device has adjustability and selectivity.

[0056] Example 1

[0057] Weigh 10 kg of natural quartz sand fracturing proppant, after water washing process, put it into the natural quartz sand fracturing proppant low water holding rate sand preparation device ( Figure 1 , the cross section of the external rotating cylinder is rectangular), the upper motor is turned on to rotate the internal rotating cylinder at a speed of 6000r / min, and the lower motor is turned on to rotate the external rotating cylinder at a speed of 4000r / min; the prepared silane coupling agent KH570, with a dosage of 2.0g / L, is sprayed to the monodisperse particles in circular motion through a chemical nozzle, the temperature of the external rotating cylinder is set to 20℃, and the internal and external rotating cylinders are kept rotating for 4h; then the upper and lower motors are turned off, and all the modified monodisperse particles fall on the natural quartz sand fracturing proppant low water retention sand preparation device, and the finished product is 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 cross section of the external rotating cylinder of the natural quartz sand fracturing proppant low water retention sand preparation device is arc-shaped, such as Figure 2 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 longitudinal section of the outer rotating cylinder of the natural quartz sand fracturing proppant low water retention sand preparation device is conical, such as Figure 3 The performance results of the obtained samples are shown in Table 1.

[0062] Example 4

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

[0064] Example 5

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

[0066] Example 6

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

[0068] Example 7

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

[0070] Example 8

[0071] The difference between this embodiment and embodiment 1 is that the chemical nozzle of the natural quartz sand fracturing proppant low water retention sand preparation device is located at the bottom of the external rotating cylinder, such as Figure 8 The performance results of the obtained samples are shown in Table 1.

[0072] Table 1 Performance results of samples of Examples 1 to 8

[0073] Example 1 2 3 4 5 6 7 8 Whether it is agglomerated or agglomerated no no no no no no no no

[0074] It can be seen from Examples 1 to 8 that by changing and adjusting the natural quartz sand fracturing proppant low water retention sand preparation device, the samples can effectively avoid sample agglomeration and caking, indicating that the natural quartz sand fracturing proppant low water retention sand preparation device has adjustability and selectivity.

[0075] Examples 1, 9 to 12 are to control a single variable: using silane coupling agent KH570, natural quartz sand fracturing proppant low water retention sand preparation device such as Figure 1, remain unchanged; what changed was the amount of KH570, which was 2.0g / L, 0.5g / L, 1.0g / L, 1.5g / L, and 2.5g / L respectively. The examples illustrate that the amount of chemical substances has an impact on the performance of the samples.

[0076] Example 9

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

[0078] Example 10

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

[0080] Embodiment 11

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

[0082] Example 12

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

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

[0085] Example 1 9 10 11 12 Whether it is agglomerated or agglomerated no yes yes part no

[0086] It can be seen from Examples 1, 9 to 12 that when the amount of KH570 is small, the sample is prone to agglomeration and caking. When the amount reaches 2.0 g / L, the sample does not agglomerate or agglomerate. Considering the economy, the amount of 2.0 g / L is selected as the best. The results show that the amount of KH570 has a significant effect on whether the sample agglomerates or agglomerates, and further silane coupling agents and chemicals will have a significant impact on the performance of the sample.

[0087] Examples 1, 13 to 16 are to control a single variable: a natural quartz sand fracturing proppant low water holding rate sand preparation device such as Figure 1 The amount of chemical substances used was 2.0 g / L, which remained unchanged; what changed was the types of chemical substances, which were KH570, dopamine, polyvinyl alcohol, F127, and micro-nano silica. Examples were used to illustrate the effect of selecting hydrophobic and lipophilic chemical substances on sample performance.

[0088] Embodiment 13

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

[0090] Embodiment 14

[0091] The difference between this embodiment and embodiment 1 is that the chemical substance is polyvinyl alcohol. The performance results of the obtained samples are shown in Table 3.

[0092] Embodiment 15

[0093] The difference between this embodiment and embodiment 1 is that the chemical substance type is F127. The performance results of the obtained samples are shown in Table 3.

[0094] Example 16

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

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

[0097] Example 1 13 14 15 16 Whether it is agglomerated or agglomerated no no no no no

[0098] It can be seen from Examples 1 and 13 to 16 that by using hydrophobic and lipophilic chemical substances, even if the type of chemical substances is changed, the samples can effectively avoid sample agglomeration and caking.

[0099] Examples 1, 17 to 19 are to control a single variable: a natural quartz sand fracturing proppant low water holding rate sand preparation device such as Figure 1 , the dosage of KH570 is 2.0g / L, which remains unchanged; what is changed is the reaction temperature, which is 20℃, 40℃, 60℃, and 80℃ respectively. The influence of temperature on the preparation process is explained through examples.

[0100] Embodiment 17

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

[0102] Embodiment 18

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

[0104] Embodiment 19

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

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

[0107] Example 1 17 18 19 Whether it is agglomerated or agglomerated no no no no Reaction time (h) 4 3.2 2.8 2.4 Whether it consumes energy no no generally yes

[0108] It can be seen from Examples 1 and 17 to 19 that increasing the reaction temperature can speed up the reaction rate, but it is easy to consume energy; although increasing the reaction temperature can effectively prevent the sample from agglomerating and caking, the reaction temperature needs to be selected according to actual production.

[0109] Examples 20 to 23 are examples of changes in the rotation speeds of the inner rotating drum and the outer rotating drum.

[0110] Embodiment 20

[0111] Weigh 10 kg of natural quartz sand fracturing proppant, after water washing process, put it into the natural quartz sand fracturing proppant low water holding rate sand preparation device ( Figure 1 , the cross section of the external rotating cylinder is rectangular), the upper motor is turned on to rotate the internal rotating cylinder at a speed of 5200r / min, and the lower motor is turned on to rotate the external rotating cylinder at a speed of 3000r / min; the prepared silane coupling agent KH570, with a dosage of 2.0g / L, is sprayed to the monodisperse particles in circular motion through a chemical nozzle, the temperature of the external rotating cylinder is set to 20℃, and the internal and external rotating cylinders are kept rotating for 4h; then the upper and lower motors are turned off, and all the modified monodisperse particles fall on the natural quartz sand fracturing proppant low water retention sand preparation device, and the finished product is collected. The performance results and process influences of the obtained samples are shown in Table 5.

[0112] Embodiment 21

[0113] The difference between this embodiment and embodiment 20 is that the speed of the inner rotating drum is 4700 r / min and the speed of the outer rotating drum is 1550 r / min. The performance results of the obtained samples and the influence of the process are shown in Table 5.

[0114] Embodiment 22

[0115] The difference between this embodiment and embodiment 20 is that the speed of the inner rotating drum is 3920 r / min and the speed of the outer rotating drum is 1310 r / min. The performance results of the obtained samples and the influence of the process are shown in Table 5.

[0116] Embodiment 23

[0117] The difference between this embodiment and embodiment 20 is that the speed of the inner rotating drum is 2350 r / min and the speed of the outer rotating drum is 1200 r / min. The performance results of the obtained samples and the influence of the process are shown in Table 5.

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

[0119] Example 1 20 21 22 Whether it is agglomerated or agglomerated no no no no Reaction time (h) 4.6 5.0 5.7 7.5 Whether it consumes energy no generally yes yes

[0120] It can be seen from Examples 20 to 23 that by reducing the rotation speed of the inner rotating drum and the outer rotating drum, the sample can effectively avoid sample agglomeration and caking, which prolongs the reaction time and increases energy consumption to a certain extent. It is necessary to select a suitable rotation speed according to actual production.

[0121] By comparing the results of the above examples, it can be seen that the natural quartz sand fracturing proppant low water-holding sand preparation process and its products provided by the present invention, the obtained low water-holding sand can effectively avoid sample agglomeration and caking, thereby avoiding pump jamming, wear, blockage, etc. caused by the fracturing process. Since there is no need to use a drying process, the purpose of saving process steps and reducing energy consumption is achieved. The overall operation is simple and easy to implement, and it can be promoted and applied in the field of fracturing materials in the oil and natural gas industry.

[0122] In order to achieve the above-mentioned purpose, the main technical means adopted in the present invention shall be described clearly, completely and accurately, and the essential content of the invention shall be explained. The degree of disclosure shall be based on the understanding and implementation of the technology by ordinary technicians in the relevant technical field.

Claims

1. A process for preparing natural quartz sand fracturing proppant with low water holding rate, characterized in that: The method is implemented by using a low water retention 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 sieve holes (5) are provided on the side wall of the inner rotating cylinder (4), and a sample inlet (3) is provided 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 substance nozzle (6) is provided on the outer rotating cylinder (7), and the chemical substance nozzle (6) faces the inner rotating cylinder (4); The top of the inner rotating cylinder (4) is connected to a rotating shaft (2), and the rotating shaft (2) is connected to the output shaft of the upper motor (1); the bottom of the outer rotating cylinder (7) is connected to the output shaft of the lower motor (8); the upper motor (1) and the lower motor (8) are respectively used to drive the inner rotating cylinder (4) and the outer rotating cylinder (7) to rotate around the axis; The preparation process comprises: (1) washing the natural quartz sand fracturing proppant with water, and then adding the washed proppant into the inner rotating cylinder (4) from the injection port (3), turning on the upper motor (1) to rotate the inner rotating cylinder (4), and turning on the lower motor (8) to rotate the outer rotating cylinder (7); the natural quartz sand fracturing proppant can enter the outer rotating cylinder (7) from the adjustable sieve hole (5); (2) Spraying chemical substances into the gap between the inner rotating cylinder (4) and the outer rotating cylinder (7) through a chemical substance nozzle, and keeping the inner rotating cylinder (4) and the outer rotating cylinder (7) rotating continuously for 2 to 8 hours, thereby obtaining natural quartz sand fracturing proppant low water holding rate sand; wherein the chemical substances are used to modify the natural quartz sand fracturing proppant so that the natural quartz sand fracturing proppant has hydrophobicity.

2. The process for preparing natural quartz sand fracturing proppant low water holding rate sand according to claim 1, characterized in that: 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 process for preparing natural quartz sand fracturing proppant with low water holding rate according to claim 1, characterized in that: The mass of the chemical substance accounts for 0.5% to 2.5% of the mass of the natural quartz sand fracturing proppant.

4. The process for preparing natural quartz sand fracturing proppant with low water holding rate according to claim 1, characterized in that: The rotation speed of the inner rotating drum (4) is 1000 to 8000 r / min, and the rotation speed of the outer rotating drum (7) is 1000 to 6000 r / min.

5. The process for preparing natural quartz sand fracturing proppant with low water holding rate according to claim 1, characterized in that: The temperature of the external rotating drum (7) is 20°C to 80°C.

6. The process for preparing natural quartz sand fracturing proppant with low water holding rate according to claim 1, characterized in that: The low water retention sand preparation device further comprises a sample collector (9), wherein the sample collector (9) is arranged at the inner side of the bottom of the external rotating cylinder (7).

7. The process for preparing natural quartz sand fracturing proppant with low water holding rate according to claim 1, characterized in that: The chemical substance nozzle (6) is integrated on the side wall or the inner side of the bottom of the outer rotating drum (7).

8. The process for preparing natural quartz sand fracturing proppant with low water holding rate according to claim 1, characterized in that: The shape of the adjustable sieve hole is circular, rectangular, elliptical or polygonal.

9. Natural quartz sand fracturing proppant low water holding rate sand obtained by the preparation method according to any one of claims 1 to 8.

10. A natural quartz sand fracturing proppant low water holding rate sand preparation device, characterized in that: include: 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 sieve holes (5) are provided on the side wall of the inner rotating cylinder (4), and a sample inlet (3) is provided 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 substance nozzle (6) is provided on the outer rotating cylinder (7), and the chemical substance nozzle (6) faces the inner rotating cylinder (4); The top of the inner rotating cylinder (4) is connected to a rotating shaft (2), and the rotating shaft (2) is connected to an output shaft of an upper motor (1); the bottom of the outer rotating cylinder (7) is connected to an output shaft of a lower motor (8); the upper motor (1) and the lower motor (8) are respectively used to drive the inner rotating cylinder (4) and the outer rotating cylinder (7) to rotate around an axis.

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