CN116218508A - Low-density propping agent and preparation method thereof - Google Patents

Abstract

Embodiments of the present disclosure provide a low density proppant and a method of making the same, the method comprising: mixing nut shell particles with the particle size ranging from 106 mu m to 710 mu m with thermosetting phenolic resin with preset solid content according to the mass ratio of 10: (2-5) uniformly mixing, dipping and stirring until no obvious liquid is on the surface, thus obtaining first semi-finished product particles; transferring the first semi-finished product particles into a granulator, adding a certain amount of coating material or binder and nut shell powder, stirring until the surfaces of the particles are smooth, curing for a certain time at a preset temperature, and screening to obtain the low-density propping agent. In the preparation method of the embodiment of the disclosure, low-density nut shell particles are adopted as propping agent particles, the propping agent particles are immersed in phenolic resin to increase the strength of the particles, then the binding agent and the nut shell powder or coating layer material with lower density are coated, the sphericity of the particles is improved, and the propping agent with high strength and low density is obtained, so that the requirements of the propping agent on pumping and fracturing fluid performance are reduced.

Description

Low-density propping agent and preparation method thereof

Technical Field

The embodiment of the disclosure belongs to the technical field of propping agents for oil and gas wells, and particularly relates to a low-density propping agent and a preparation method thereof.

Background

Fracturing stimulation is an important technique for oil and gas well exploitation stimulation. Propping agent is the key material for fracturing construction. The propping agent is carried into and supported in the cracks of the fractured stratum by the fracturing fluid, so that the oil and gas is effectively led into the oil and gas well, the oil and gas yield is greatly improved, and the service life of the oil and gas well is prolonged.

The fracturing propping agent commonly used at present comprises quartz sand, ceramsite, resin coated particles and the like. The quartz sand has the advantages of cheapest price, low relative density and convenient construction pumping, but the quartz sand has low strength, poor sphericity and high breaking rate, thereby reducing the diversion capability of cracks and being particularly not suitable for deep wells with high closing pressure. The sphericity of the resin coated quartz sand is improved, the breakage resistance is greatly improved, and the flow conductivity is better than that of the quartz sand but still lower than that of the ceramsite. The ceramic proppant manufactured by taking bauxite as a main material has better sphericity, crushing resistance and diversion capacity than quartz sand, and is widely used in deep oil and gas wells. But the density of the ceramsite (apparent density is generally more than 3.0g/cm ³ ) Specific quartz sand (apparent density is generally greater than 2.65g/cm ³ Left and right), higher requirements are put on pumping conditions and performance of fracturing fluid, and construction difficulty is increased; short supporting bands are easy to generate in application and are accumulated at ports of cracks, so that the flow guiding is extremely adverse, and the later oil outlet effect is affected. In contrast, the low-density propping agent has better void ratio, is easier to carry, can greatly reduce the viscosity of fracturing fluid, reduces the damage to pipelines and pumps, can even realize clean water fracturing, and effectively reduces the construction difficulty and the oil extraction cost; in addition, the flow guiding and reducing rate of the low-density propping agent is lower, and a good oil extraction effect can be generated. The development of low density proppants is therefore the direction of proppant research. Moreover, the traditional propping agent needs to be sintered at a high temperature, so that the energy consumption is increased.

The prior art has at least the following problems: the lack of a proppant which ensures the strength and reduces the density, thereby reducing the requirements on the pumping and fracturing fluid performance, and reducing the cost during construction; and the propping agent can avoid high-temperature sintering formation, thereby saving energy consumption.

Disclosure of Invention

Embodiments of the present disclosure aim to solve at least one of the technical problems existing in the prior art, and provide a low-density proppant and a method for preparing the same.

One aspect of an embodiment of the present disclosure provides a method of preparing a low density proppant. The method comprises the following steps:

mixing nut shell particles with the particle size ranging from 106 mu m to 710 mu m with thermosetting phenolic resin with preset solid content according to the mass ratio of 10: (2-5) uniformly mixing, dipping and stirring until no obvious liquid is on the surface, thus obtaining first semi-finished product particles;

transferring the first semi-finished product particles into a high-speed granulator, and adding the particles with the mass ratio of (2-3) to the first semi-finished product particles: (60-75) wood powder or nut shell powder with the particle size not more than 45 mu m, and heating and curing for 30-60 min after uniform dispersion to obtain second semi-finished product particles;

transferring the second semi-finished product particles into the high-speed granulator, adding a certain amount of binder, and uniformly stirring; adding a certain amount of nut shell powder, stirring until the nut shell powder is fully coated on the particles, reducing the speed to a preset rotating speed, adding a certain amount of powder for dispersion, and transferring the powder into a low-speed granulator;

and transferring the mixture to a low-speed granulator to ensure that the surface of the granules is smooth, curing for a certain time at a preset temperature, and screening to obtain the low-density propping agent.

Optionally, the binder is prepared by the following steps:

mixing liquid bisphenol a epoxy resin and liquid modified diaminodiphenyl methane with preset viscosity according to a mass ratio of 100: (10-30) and evenly mixing to obtain the adhesive.

Optionally, the mass ratio of the second semi-finished particles, the binder and the nut shell powder is (125-155): (2-7): (10-40).

Optionally, the preset rotation speed is 500-1000 rpm.

Optionally, the parameters of the low density proppant include:

bulk density in the range of 0.85g/cm ³ ～1.0g/cm ³ The apparent density is in the range of 1.15g/cm ³ ～1.35g/cm ³ The acid solubility range is 1% -4%, the sphericity range is 0.7-0.9, and the 52MPa breaking rate range is 4% -9%.

Another aspect of an embodiment of the present disclosure provides a method of preparing a low density proppant. The method comprises the following steps:

mixing nut shell particles with the particle size ranging from 106 mu m to 710 mu m with thermosetting phenolic resin with preset solid content according to the mass ratio of 10: (2-5) uniformly mixing, dipping and stirring until no obvious liquid is on the surface, thus obtaining first semi-finished product particles;

and transferring the first semi-finished product particles into a granulator, adding a certain amount of coating layer materials, transferring the first semi-finished product particles into the granulator until fine particles are completely adhered to the surfaces of coarse particles, adding a certain amount of powder, continuing transferring the first semi-finished product particles until the surfaces of the particles are smooth, curing the first semi-finished product particles for a certain time at a preset temperature, and screening the first semi-finished product particles to obtain the low-density propping agent.

Optionally, the coating layer material is prepared by the following steps:

mixing shell powder with particle size not greater than 45 μm and thermosetting phenolic resin with solid content of 50-70% in the mass ratio of 2 (0.5-1.5), soaking for certain time to obtain the coating material.

Optionally, the mass ratio of the first semi-finished product particles to the coating layer material is (12-15): (2-3).

Optionally, the parameters of the low density proppant include:

bulk density in the range of 0.8g/cm ³ ～0.95g/cm ³ The apparent density is 1.05g/cm ³ ～1.25g/cm ³ The acid solubility range is 1% -4%, the sphericity range is 0.7-0.85, and the 52MPa breaking rate range is 6% -9%.

Another aspect of an embodiment of the present disclosure provides a low density proppant. Prepared by the preparation method.

In the preparation method of the low-density propping agent, thermosetting phenolic resin is adopted to impregnate the nut shell particles, so that the thermosetting phenolic resin is permeated into micropores of the nut shell particles, and the strength of the nut shell particles is improved; the binding agent and the nut shell powder or the coating layer material are further coated on the surface of the particles, so that defects on the surface of the particles are repaired, the coating amount of the material on the surface of the particles is increased, and the sphericity and the strength of the particles are improved; moreover, the method disclosed by the embodiment of the invention has low energy consumption, only carries out low-temperature heating, and does not need high-temperature sintering.

Drawings

FIG. 1 is a schematic flow diagram of a method of preparing a low density proppant according to an embodiment of the disclosure;

fig. 2 is a flow chart of a method of preparing a low density proppant according to another embodiment of the disclosure.

Detailed Description

In order to enable those skilled in the art to better understand the technical solutions of the embodiments of the present disclosure, the embodiments of the present disclosure are described in further detail below with reference to the accompanying drawings and detailed description.

As shown in fig. 1, a method for preparing an ultra-low density proppant, the method S100 includes:

s110, mixing nut shell particles with the particle size ranging from 106 mu m to 710 mu m with thermosetting phenolic resin with preset solid content, wherein the mass ratio is 10: (2-5) uniformly mixing, dipping and stirring until no obvious liquid is on the surface, thus obtaining first semi-finished product particles.

As an example, the nut shell type particles may be one or more of walnut shells, apricot shells, peach kernel shells, hazelnut shells, and hawaii shells. The nut shell particles are crushed and processed, and can be directly purchased in the market, or can be obtained by adopting the existing nut shell particle processing method, and the particle size range of the nut shell particles is not described herein.

According to the embodiment of the disclosure, 1kg of nut shell particles with the particle size ranging from 106 mu m to 710 mu m and 200g to 500g of thermosetting phenolic resin with the solid content of 50% -70% can be uniformly mixed, immersed and stirred until no obvious liquid exists on the surfaces of the particles, and then the first semi-finished product particles are obtained. The thermosetting phenolic resin can impregnate the nut shell particles, penetrate into micropores of the nut shell particles, and improve the particle strength. When stirred until there is no apparent liquid on the particle surface, this indicates that the thermosetting phenolic resin has penetrated into the micropores of the nut shell particles.

S120, transferring the first semi-finished product particles into a high-speed granulator, and adding the particles with the mass ratio of (2-3) to the first semi-finished product particles: (60-75) wood powder or nut shell powder with the particle diameter not more than 45 mu m, and heating and curing for 30-60 min after uniform dispersion to obtain second semi-finished product particles.

As an example, the high-speed granulator may be a granulating device with a rotation speed of up to 3000 rpm, so that the high-speed granulator may also be called a powerful granulator or a hybrid granulator, and the high-speed granulator has three functions of stirring uniformly, granulating and coating, where the rotation speed of the high-speed granulator may be about 1800 rpm, and is mainly used for coating the surface of the first semi-finished product particles with wood flour or nut shell powder. The nut shell meal may also be replaced with bakelite powder. In the embodiment of the disclosure, 50g of wood powder or nut shell powder with the particle size not more than 45 mu m can be added, and the mixture is heated to 80-160 ℃ for 0.2-3 hours after being uniformly dispersed, so as to promote the thermosetting phenolic resin to be cured. The wood flour or nut shell powder mainly plays a role in dispersing particles and prevents the particles from being bonded into blocks in the heating and curing process.

S130, transferring the second semi-finished product particles into the high-speed granulator, adding a certain amount of binder, and uniformly stirring; adding a certain amount of nut shell powder, stirring until the nut shell powder is fully coated on the particles, reducing the rotation speed to a preset value, adding a certain amount of powder for dispersion, and transferring the powder into a low-speed granulator.

As an example, at this time, the high-speed granulator may be the same as the aforementioned high-speed granulator, and the rotation speed may be set to about 1800 rpm. The nut shell meal may also be replaced with bakelite powder. According to the embodiment of the disclosure, 30g of the binder can be added and stirred uniformly, 150g of the nut shell powder with the particle size not more than 45 mu m is added and stirred until the nut shell powder is fully coated on the particles, the binder bonds the nut shell powder on the surfaces of the particles, defects on the surfaces of the particles are repaired, and the sphericity of the particles is improved. In order to improve the sphericity of the particles, 30g of the binder can be added for uniform stirring, 150g of the nut shell powder with the particle size not more than 45 mu m is added for stirring until the nut shell powder is fully coated on the particles, and the binder and the nut shell powder can be added for multiple times according to actual needs without limiting the times of adding the binder and the nut shell powder. In the embodiment of the disclosure, the rotating speed of the high-speed granulator is reduced to a preset rotating speed of 500-1000 rpm, 50-100 g of powder is added for dispersion, and the powder is transferred into the low-speed granulator for granulation. The rotating speed range of the low-speed granulator is 30-50 rpm. The powder can be one or more of nut shell powder, quartz powder, active silicon micropowder, floating beads and the like with the particle size not more than 45 microns, and the quartz powder, the active silicon micropowder and the floating beads have acid resistance. The low-speed granulator can be a disc granulator or a round pot granulator, and the rotating speed of the disc granulator or the round pot granulator is low, generally only tens of revolutions per minute, and the low-speed granulator is mainly used for granulation.

Illustratively, the mass ratio of the second semi-finished particles, the binder, and the nut shell powder is (125-155): (2-7): (10-40).

As an example, the binder and the nut shell powder may be added to the high-speed granulator in one or two times according to the above mass ratio, and may be adjusted according to actual situations, which is not described herein.

The preset rotational speed may be, for example, 500 rpm to 1000 rpm.

As an example, the preset rotation speed is lower, and the powder is poured to disperse to prevent the particles from adhering.

Illustratively, the binder is prepared by:

mixing liquid bisphenol a epoxy resin and liquid modified diaminodiphenyl methane with preset viscosity according to a mass ratio of 100: (10-30) and evenly mixing to obtain the adhesive.

As an example, the binder may be prepared in advance. The preset viscosity is 0.5 Pa.S-2 Pa.S, and the adhesive is preferably used up within 4 hours.

And S140, transferring the mixture to a low-speed granulator until the surface of the granules is smooth, curing the granules for a certain time at a preset temperature, and screening the granules to obtain the low-density propping agent.

As an example, the granulating time in the low-speed granulator may be set according to the actual situation, and granulating is performed until the surface of the granules is smooth. The preset temperature range of the embodiment of the disclosure is 100-400 ℃, and the curing time range is 1-4 hours.

Exemplary parameters of the low density proppant include:

bulk density in the range of 0.85g/cm ³ ～1.0g/cm ³ The apparent density range is 1.15g/cm ³ ～1.35g/cm ³ The acid solubility range is 1% -4%, the sphericity range is 0.7-0.9, and the 52MPa breaking rate range is 4% -9%.

As an example, the parameters of the proppant prepared using the preparation method of the presently disclosed embodiments are as described above, and the proppant prepared using the above preparation method minimizes the proppant density while guaranteeing the proppant strength. Therefore, the requirements of propping agent on pumping and fracturing fluid performance are reduced, meanwhile, the construction cost is reduced, and a good oil extraction effect is obtained.

Another aspect of embodiments of the present disclosure provides a low density proppant. Prepared by the preparation method.

As shown in fig. 2, another embodiment of the present disclosure provides a method for preparing an ultra-low density proppant, the method S200 comprising:

s210, mixing nut shell particles with the particle size ranging from 106 mu m to 710 mu m with thermosetting phenolic resin with preset solid content, wherein the mass ratio is 10: (2-5) uniformly mixing, dipping and stirring until no obvious liquid is on the surface, thus obtaining first semi-finished product particles.

As an example, the nut shell type particles may be one or more of walnut shells, apricot shells, peach kernel shells, hazelnut shells, and hawaii shells. According to another embodiment of the present disclosure, 1kg of nut shell particles with particle diameters ranging from 106 μm to 710 μm and 200g to 500g of thermosetting phenolic resin with a solid content of 50% -70% may be uniformly mixed, impregnated and stirred until no obvious liquid is present on the particle surfaces, thereby obtaining first semi-finished product particles. Similarly, the thermosetting phenolic resin can impregnate the nut shell particles, penetrate into micropores of the nut shell particles and improve the particle strength.

S220, transferring the first semi-finished product particles into a granulator, adding a certain amount of coating materials, transferring the particles into the granulator until the fine particles are completely adhered to the surfaces of the coarse particles, adding a certain amount of powder, continuing transferring the particles until the surfaces of the particles are smooth, curing for a certain time at a preset temperature, and screening to obtain the low-density propping agent.

As an example, the granulator may be a granulation device with a rotation speed of several thousand rpm, and the rotation speed of the granulator may reach around 1800 rpm, and mainly coats the surface of the first semi-finished product particle with the coating material. In another embodiment of the disclosure, 200 g-300 g of coating material is added, the mixture is transferred to the granulator until fine particles are completely adhered to the surfaces of coarse particles, 50g of powder is added, the mixture is continuously transferred to the surface of the particles to be smooth, and then the mixture is maintained for a certain time range of 1 h-4 h at a preset temperature range of 100-400 ℃, and the low-density propping agent is obtained after screening. The powder can be one or more of nut shell powder, quartz powder, active silicon micropowder, floating beads and the like with the particle size not more than 45 mu m, the quartz powder, the active silicon micropowder and the floating beads have acid resistance,

illustratively, the coating material is prepared by the steps of:

mixing shell powder with particle size not greater than 45 μm and thermosetting phenolic resin with solid content of 50-70% in the mass ratio of 2 (0.5-1.5), soaking for certain time to obtain the coating material.

The coating layer material of the other embodiment of the disclosure can be prepared in advance, and 1kg of shell powder with the particle size not more than 45 mu m and 500g of thermosetting phenolic resin with the solid content of 50% -70% can be uniformly mixed and then soaked for 2 hours for standby.

Illustratively, the mass ratio of the first semifinished particles to the coating material is (12-15): (2-3).

Exemplary parameters of the low density proppant include:

bulk density in the range of 0.8g/cm ³ ～0.95g/cm ³ The apparent density is 1.05g/cm ³ ～1.25g/cm ³ The acid solubility range is 1% -4%, the sphericity range is 0.7-0.85, and the 52MPa breaking rate range is 6% -9%.

As an example, the parameters of the proppant prepared using the preparation method of another embodiment of the present disclosure are as described above, and the proppant prepared using the preparation method described above maximally reduces the proppant density while guaranteeing the proppant strength. Therefore, the requirements of propping agent on pumping and fracturing fluid performance are reduced, meanwhile, the construction cost is reduced, and a good oil extraction effect is obtained.

Another aspect of another embodiment of the present disclosure provides a low density proppant. Prepared by the preparation method.

The two methods for preparing propping agents of the present disclosure adopt a composite coating technology, namely, first, the nut shell particles are mixed with thermosetting phenolic resin, so that the strength of the nut shell particles is enhanced; and then coating the surface of the nut shell particles with a coating layer material or the nut shell powder and a binder, wherein the coating layer material or the nut shell powder and the binder are composed of nut shell powder with low density and thermosetting phenolic resin, so that the coating amount of the particle surface material is increased, the defect of the particle surface is effectively filled, and the sphericity and the strength are improved. According to the method, the nut shell particles, the nut shell powder and the thermosetting phenolic resin are adopted as main raw materials, the traditional bauxite is replaced, the density of the propping agent is effectively reduced, the nut shell particles are immersed in the thermosetting phenolic resin to increase the strength of the particles, the composite coating technology is adopted to improve the sphericity of the particles, high-temperature sintering is not needed, only low-temperature heating is carried out, the energy consumption is low, the obtained propping agent is high in strength and low in density, the requirements of the propping agent on pumping and fracturing fluid performance are reduced, meanwhile, the construction cost is reduced, and a better oil extraction effect is obtained.

Example 1

S110, weighing 1kg of nut shell particles with the particle size ranging from 425 mu m to 710 mu m, uniformly mixing 250g of thermosetting phenolic resin with the solid content of 50% -70%, dipping, and stirring until no obvious liquid exists on the surface, thereby obtaining first semi-finished product particles.

S120, transferring the first semi-finished product particles into a high-speed granulator, adding 50g of walnut shell powder with the particle size not more than 45 mu m, uniformly dispersing, heating to 120 ℃ and curing for 30-60 minutes to obtain second semi-finished product particles.

S130, transferring the second semi-finished product particles into a high-speed granulator, adding 30g of binder, stirring uniformly, adding 150g of nut shell powder with the particle size not more than 45 mu m, stirring until all the nut shell powder is coated on the particles, reducing the rotating speed, adding 50g of glass beads, dispersing, and transferring the mixture into a low-speed granulator (the low-speed granulator can be a disc granulator or a round pot granulator).

The rotating speed of the high-speed granulator can be about 1800 rpm, the rotating speed can be reduced to 500 rpm after the nut shell powder and the binder are coated on the particles, and 50g of glass beads are added for dispersion and then transferred into the low-speed granulator.

S140, transferring the mixture into a low-speed granulator until the surface of the granules is smooth, heating the granules to 120 ℃ for curing for 2 hours, and sieving the granules by a 425-850 mu m sieve to obtain the low-density proppant.

The rotation speed range of the low-speed granulator is 30 rpm, and the rotation speed can be determined according to actual practice, which is not described herein.

The adhesive is prepared by the following steps:

mixing liquid bisphenol a epoxy resin and liquid modified diaminodiphenyl methane with the viscosity of 0.5 Pa.S-2 Pa.S according to the mass ratio of 100:15, uniformly mixing and stirring to obtain the adhesive. The binder is prepared in advance, preferably within 4 hours.

Parameters of the resulting low density proppant herein include: bulk density of 0.85g/cm ³ Apparent density of 1.15g/cm ³ The acid solubility is 1.4%, the sphericity is 0.8, and the 52MPa breaking rate is 7.5%.

Example 2

S110, weighing 1kg of nut shell particles with the particle size ranging from 425 mu m to 710 mu m, uniformly mixing 250g of thermosetting phenolic resin with the solid content of 50% -70%, dipping, and stirring until no obvious liquid exists on the surface, thereby obtaining first semi-finished product particles.

S120, transferring the first semi-finished product particles into a high-speed granulator, adding 50g of walnut shell powder with the particle size not more than 45 mu m, uniformly dispersing, heating to 120 ℃ and curing for 30-60 minutes to obtain second semi-finished product particles.

S130, transferring the second semi-finished product particles into a high-speed granulator, adding 30g of binder, stirring uniformly, adding 150g of nut shell powder with the particle size not more than 45 mu m, stirring until all the nut shell powder is coated on the particles, reducing the rotating speed, adding 50g of quartz powder, dispersing, and transferring the mixture into a low-speed granulator (the low-speed granulator is a disc granulator or a round pot granulator).

The rotating speed of the high-speed granulator can be about 1800 rpm, the rotating speed can be reduced to 800 rpm after the nut shell powder and the binder are coated on the particles, and 50g of glass beads are added for dispersion and then transferred into the low-speed granulator.

S140, transferring the mixture into a low-speed granulator until the surface of the granules is smooth, heating the granules to 120 ℃ for curing for 2 hours, and sieving the granules by a 425-850 mu m sieve to obtain the low-density proppant.

The rotation speed range of the low-speed granulator is 50 rpm, and the rotation speed can be determined according to actual practice, which is not described herein.

The adhesive is prepared by the following steps:

mixing liquid bisphenol a epoxy resin and liquid modified diaminodiphenyl methane with the viscosity of 0.5 Pa.S-2 Pa.S according to the mass ratio of 100:20, uniformly mixing and stirring to obtain the adhesive. The binder is prepared in advance, preferably within 4 hours.

Parameters of the low density proppant herein include: bulk density of 0.95g/cm ³ Apparent density of 1.25g/cm ³ The acid solubility is 1.3%, the sphericity is 0.9, and the 52MPa breaking rate is 6.5%.

Example 3

S210, weighing 1kg of nut shell particles with the particle size ranging from 300 mu m to 500 mu m, uniformly mixing 200g of thermosetting phenolic resin with the solid content of 50% -70%, dipping, and stirring until no obvious liquid exists on the surface, thereby obtaining first semi-finished product particles.

S220, transferring the first semi-finished product particles into a granulator, adding 200g of coating layer materials, transferring in the granulator to enable fine particles to be completely adhered to the surfaces of coarse particles, simultaneously adding 50g of quartz powder, continuing transferring until the surfaces of the particles are smooth, enabling the surfaces of the coarse particles to be smooth, heating to 30 ℃ for curing for 1h, and screening to obtain the low-density propping agent.

The rotational speed of the granulator may be about 1800 rpm, and the coating material is coated on the surface of the particles.

The coating layer material is prepared by the following steps:

1kg of shell powder with the particle size not more than 45 mu m and 500g of thermosetting phenolic resin with the solid content of 50% -70% are uniformly mixed and then soaked for 2 hours, so as to obtain the coating material. The coating layer material is prepared in advance.

Parameters of the low density proppant herein include: bulk density of 0.89g/cm ³ Apparent density of 1.15g/cm ³ The acid solubility is 3.4%, the sphericity is 0.8, and the 52MPa breaking rate is 8.0%.

Example 4

S210, weighing 1kg of nut shell particles with the particle size ranging from 300 mu m to 500 mu m, uniformly mixing 300g of thermosetting phenolic resin with the solid content of 50% -70%, dipping, and stirring until no obvious liquid exists on the surface, thereby obtaining first semi-finished product particles.

S220, transferring the first semi-finished product particles into a granulator, adding 200g of coating layer materials, transferring in the granulator to enable fine particles to be completely adhered to the surfaces of coarse particles, simultaneously adding 50g of active silicon micro powder, continuing transferring until the surfaces of the particles are smooth, enabling the surfaces of the coarse particles to be smooth, heating to 100 ℃ and curing for 2 hours, and screening to obtain the low-density propping agent.

The rotational speed of the granulator may be about 1800 rpm, and the coating material is coated on the surface of the particles.

The coating layer material is prepared by the following steps:

1kg of shell powder with the particle size not larger than 45 mu m is added with 500g of thermosetting phenolic resin with the solid content of 50-70%, and the mixture is soaked for 2 hours for standby after uniform mixing.

Parameters of the low density proppant herein include: bulk density of 0.95g/cm ³ Apparent density of 1.25g/cm ³ The acid solubility is 1% -4%, the sphericity is 0.8, and the 52MPa breaking rate is 6.5%.

It is to be understood that the above implementations are merely exemplary implementations employed to illustrate the principles of the disclosed embodiments, which are not limited thereto. Various modifications and improvements may be made by those skilled in the art without departing from the spirit and substance of the embodiments of the disclosure, and these modifications and improvements are also considered to be within the scope of the embodiments of the disclosure.

Claims (10)

1. A method of making a low density proppant, the method comprising:

mixing nut shell particles with the particle size ranging from 106 mu m to 710 mu m with thermosetting phenolic resin with preset solid content according to the mass ratio of 10: (2-5) uniformly mixing, dipping and stirring until no obvious liquid is on the surface, thus obtaining first semi-finished product particles;

transferring the first semi-finished product particles into a high-speed granulator, and adding the particles with the mass ratio of (2-3) to the first semi-finished product particles: (60-75) wood powder or nut shell powder with the particle size not more than 45 mu m, and heating and curing for 30-60 min after uniform dispersion to obtain second semi-finished product particles;

transferring the second semi-finished product particles into the high-speed granulator, adding a certain amount of binder, and uniformly stirring; adding a certain amount of nut shell powder, stirring until the nut shell powder is fully coated on the particles, reducing the speed to a preset rotating speed, adding a certain amount of powder for dispersion, and transferring the powder into a low-speed granulator;

and transferring the mixture to a low-speed granulator to ensure that the surface of the granules is smooth, curing for a certain time at a preset temperature, and screening to obtain the low-density propping agent.

2. The method of claim 1, wherein the binder is prepared by:

mixing liquid bisphenol a epoxy resin and liquid modified diaminodiphenyl methane with preset viscosity according to a mass ratio of 100: (10-30) and evenly mixing to obtain the adhesive.

3. The method according to claim 2, characterized in that the mass ratio of the second semi-finished granules, the binder and the nut shell powder is (125-155): (2-7): (10-40).

4. The method according to claim 2, wherein the preset rotational speed is 500 rpm to 1000 rpm.

5. The method of any one of claims 1 to 4, wherein the parameters of the low density proppant comprise:

bulk density in the range of 0.85g/cm ³ ～1.0g/cm ³ The apparent density range is 1.15g/cm ³ ～1.35g/cm ³ The acid solubility range is 1% -4%, the sphericity range is 0.7-0.9, and the 52MPa breaking rate range is 4% -9%.

6. A method of making a low density proppant, the method comprising:

mixing nut shell particles with the particle size ranging from 106 mu m to 710 mu m with thermosetting phenolic resin with preset solid content according to the mass ratio of 10: (2-5) uniformly mixing, dipping and stirring until no obvious liquid is on the surface, thus obtaining first semi-finished product particles;

and transferring the first semi-finished product particles into a granulator, adding a certain amount of coating layer materials, transferring the first semi-finished product particles into the granulator until fine particles are completely adhered to the surfaces of coarse particles, adding a certain amount of powder, continuing transferring the first semi-finished product particles until the surfaces of the particles are smooth, curing the first semi-finished product particles for a certain time at a preset temperature, and screening the first semi-finished product particles to obtain the low-density propping agent.

7. The method of claim 6, wherein the coating material is prepared by:

mixing shell powder with particle size not greater than 45 μm and thermosetting phenolic resin with solid content of 50-70% in the mass ratio of 2 (0.5-1.5), soaking for certain time to obtain the coating material.

8. The method according to claim 7, wherein the mass ratio of the first semifinished particles to the coating material is (12-15): (2-3).

9. The method of any one of claims 6 to 8, wherein the parameters of the low density proppant comprise:

bulk density in the range of 0.8g/cm ³ ～0.95g/cm ³ The apparent density is 1.05g/cm ³ ～1.25g/cm ³ The acid solubility range is 1% -4%, the sphericity range is 0.7-0.85, and the 52MPa breaking rate range is 6% -9%.

10. A low density proppant prepared by the method of any one of claims 1 to 9.

Images