A hydrophobic ultra-low density ceramsite sand proppant and preparation method thereof

Abstract

The present invention relates to the technical field of ceramsite sand, and in particular to a hydrophobic ultra-low-density ceramsite sand proppant and a preparation method thereof. The preparation method of the hydrophobic ultra-low-density ceramsite sand proppant of the present invention comprises the following steps: grinding a powder composed of red mud, phosphogypsum, coal slag, titanium gypsum and fly ash to obtain a mixed powder; adding alumina magnetic beads and silicon dioxide magnetic beads to the mixed powder for grinding to obtain a magnetic bead mixed powder; adding a slurry composed of polyamide, N-(aminoethyl)-aminopropyl triethoxysilane, carboxymethyl cellulose and triethyl acetyl citrate to the magnetic bead mixed powder for grinding to obtain a magnetic bead mixed slurry; drying, crushing, screening and granulating the magnetic bead mixed slurry to obtain a ceramsite sand semi-finished product; firing, cooling and screening the ceramsite sand semi-finished product to obtain a hydrophobic ultra-low-density ceramsite sand proppant. The hydrophobic ultra-low-density ceramsite sand proppant obtained by the present invention has a lower density and a lower water absorption rate.

Description

Technical Field

[0001] The invention relates to the technical field of ceramsite sand proppant manufacturing, and in particular to a hydrophobic ultra-low-density ceramsite sand proppant and a preparation method thereof. Background Art

[0002] Ceramic sand generally refers to ceramsite, which is a ceramic particle. Most of the appearance of ceramsite is round or oval sphere, but some imitation gravel ceramsite is not round or oval sphere, but irregular gravel. Ceramic sand is a ceramic particle product with high fracturing strength. It is mainly used in oil fields and downhole support to increase the output of oil and natural gas. It is an environmentally friendly product.

[0003] Ceramic sand proppant is a key material for fracturing construction in oil and natural gas extraction. When the product is used in oil and gas well fracturing construction, it is filled into the rock cracks of low-permeability deposits and subjected to high-closure fracturing treatment to crack the oil and gas-bearing rock formations, supporting the cracks from closing due to stress release, thereby maintaining the high conductivity of oil and gas, which can not only increase oil and gas production, but also extend the service life of oil and gas wells; it is widely used in the development of deep oil and gas wells, increasing production, and fracturing technology. As we all know, the purpose of oil well fracturing is to increase oil production and reduce water production as much as possible; however, conventional ceramsite sand proppants do not have the effect of oil-wetting and water-repelling or the effect of oil-wetting and water-repelling is poor, resulting in excessive water content in some oil wells after fracturing, resulting in high development costs and unsatisfactory production increase effects.

[0004] Industrial solid waste refers to solid waste generated in industrial production activities. Solid waste is referred to as industrial waste, which is various waste residues, dust and other wastes discharged into the environment during industrial production. It can be divided into general industrial waste (such as blast furnace slag, steel slag, red mud, non-ferrous metal slag, fly ash, coal slag, sulfuric acid slag, waste gypsum, desulfurization ash, carbide slag and salt mud, etc.) and industrial harmful solid waste, that is, hazardous solid waste.

[0005] With the development of industrial production, the amount of industrial waste is increasing day by day. In particular, metallurgy, thermal power generation and other industries have the largest emissions. The amount of industrial waste is huge, the types are numerous, the composition is complex, and it is quite difficult to deal with. Nowadays, only a limited number of industrial wastes are used. Some industrial wastes are still mainly stored passively, some industrial wastes are disposed of by landfill, incineration, chemical conversion, microbial treatment and other methods, and some industrial wastes are thrown into the ocean. This occupies a lot of land and also pollutes the soil and water.

[0006] Therefore, in the field of expanded clay sand proppant manufacturing technology, a method for preparing expanded clay sand proppant based on industrial solid waste is provided to reduce environmental pollution; at the same time, an ultra-low-density expanded clay sand proppant with lower density and stronger hydrophobicity is provided, which has great practical significance for oil and natural gas exploitation. Summary of the invention

[0007] In view of this, the object of the present invention is to provide a method for preparing a hydrophobic ultra-low-density ceramsite sand proppant, which is based on industrial solid waste and can reduce environmental pollution. The hydrophobic ultra-low-density ceramsite sand proppant prepared by the method of the present invention has a lower density and a lower water absorption rate, and can better meet the use requirements of oil and natural gas extraction.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] In a first aspect, the present invention provides a method for preparing a hydrophobic ultra-low density ceramsite sand proppant, comprising the following steps:

[0010] Step S1. Grinding a powder consisting of red mud, phosphogypsum, coal slag, titanium gypsum and fly ash to obtain a mixed powder;

[0011] Step S2. adding alumina magnetic beads and silica magnetic beads to the mixed powder and grinding them to obtain a magnetic bead mixed powder;

[0012] Step S3. adding a slurry consisting of polyamide, N-(aminoethyl)-aminopropyl triethoxysilane, carboxymethyl cellulose and triethyl acetyl citrate to the magnetic bead mixed powder for grinding to obtain a magnetic bead mixed slurry;

[0013] Step S4. Drying, crushing, screening and granulating the magnetic bead mixed slurry to obtain a semi-finished ceramsite sand;

[0014] Step S5: sintering, cooling and screening the semi-finished ceramsite sand to obtain a hydrophobic ultra-low-density ceramsite sand proppant.

[0015] Preferably, in terms of mass fractions, the powder consists of 30-40 parts of red mud, 6-10 parts of phosphogypsum, 2-4 parts of coal slag, 3-5 parts of titanium gypsum and 20-30 parts of fly ash.

[0016] Preferably, in terms of mass fraction, the powder consists of 30 parts of red mud, 7 parts of phosphogypsum, 3 parts of coal slag, 4 parts of titanium gypsum and 25 parts of fly ash.

[0017] Preferably, the mass ratio of the silica magnetic beads to the total amount of the mixed powder is 8-20%.

[0018] Preferably, the mass ratio of the alumina magnetic beads to the total amount of the mixed powder is 5-10%.

[0019] Preferably, in terms of mass fractions, the slurry consists of 0.1-0.2 parts of polyamide, 0.005-0.008 parts of N-(aminoethyl)-aminopropyltriethoxysilane, 0.03-0.1 parts of carboxymethyl cellulose and 0.03-0.1 parts of triethyl acetyl citrate.

[0020] In a second aspect, a hydrophobic ultra-low density ceramsite sand proppant is provided, which is prepared by the preparation method described in the present invention.

[0021] Preferably, the preparation method comprises the following steps:

[0022] Step S1. Grinding a powder consisting of red mud, phosphogypsum, coal slag, titanium gypsum and fly ash to obtain a mixed powder;

[0023] Step S2. adding alumina magnetic beads and silica magnetic beads to the mixed powder and grinding them to obtain a magnetic bead mixed powder;

[0024] Step S3. adding a slurry consisting of polyamide, N-(aminoethyl)-aminopropyl triethoxysilane, carboxymethyl cellulose and triethyl acetyl citrate to the magnetic bead mixed powder for grinding to obtain a magnetic bead mixed slurry;

[0025] Step S4. Drying, crushing, screening and granulating the magnetic bead mixed slurry to obtain a semi-finished ceramsite sand;

[0026] Step S5: sintering, cooling and screening the semi-finished ceramsite sand to obtain a hydrophobic ultra-low-density ceramsite sand proppant.

[0027] Preferably, in terms of mass fractions, the powder consists of 30-40 parts of red mud, 6-10 parts of phosphogypsum, 2-4 parts of coal slag, 3-5 parts of titanium gypsum and 20-30 parts of fly ash.

[0028] Preferably, in terms of mass fraction, the powder consists of 30 parts of red mud, 7 parts of phosphogypsum, 3 parts of coal slag, 4 parts of titanium gypsum and 25 parts of fly ash.

[0029] Preferably, the mass ratio of the silica magnetic beads to the total amount of the mixed powder is 8-20%.

[0030] Preferably, the mass ratio of the alumina magnetic beads to the total amount of the mixed powder is 5-10%.

[0031] Preferably, in terms of mass fractions, the slurry consists of 0.1-0.2 parts of polyamide, 0.005-0.008 parts of N-(aminoethyl)-aminopropyltriethoxysilane, 0.03-0.1 parts of carboxymethyl cellulose and 0.03-0.1 parts of triethyl acetyl citrate.

[0032] In a third aspect, a fracturing proppant is provided, comprising the hydrophobic ultra-low density ceramsite sand proppant as described in the present invention.

[0033] Preferably, the preparation method of the hydrophobic ultra-low density ceramsite sand proppant comprises the following steps:

[0034] Step S1. Grinding a powder consisting of red mud, phosphogypsum, coal slag, titanium gypsum and fly ash to obtain a mixed powder;

[0035] Step S2. adding alumina magnetic beads and silica magnetic beads to the mixed powder and grinding them to obtain a magnetic bead mixed powder;

[0036] Step S3. adding a slurry consisting of polyamide, N-(aminoethyl)-aminopropyl triethoxysilane, carboxymethyl cellulose and triethyl acetyl citrate to the magnetic bead mixed powder for grinding to obtain a magnetic bead mixed slurry;

[0037] Step S4. Drying, crushing, screening and granulating the magnetic bead mixed slurry to obtain a semi-finished ceramsite sand;

[0038] Step S5: sintering, cooling and screening the semi-finished ceramsite sand to obtain a hydrophobic ultra-low-density ceramsite sand proppant.

[0039] Preferably, in terms of mass fractions, the powder consists of 30-40 parts of red mud, 6-10 parts of phosphogypsum, 2-4 parts of coal slag, 3-5 parts of titanium gypsum and 20-30 parts of fly ash.

[0040] Preferably, in terms of mass fraction, the powder consists of 30 parts of red mud, 7 parts of phosphogypsum, 3 parts of coal slag, 4 parts of titanium gypsum and 25 parts of fly ash.

[0041] Preferably, the mass ratio of the silica magnetic beads to the total amount of the mixed powder is 8-20%.

[0042] Preferably, the mass ratio of the alumina magnetic beads to the total amount of the mixed powder is 5-10%.

[0043] Preferably, in terms of mass fractions, the slurry consists of 0.1-0.2 parts of polyamide, 0.005-0.008 parts of N-(aminoethyl)-aminopropyltriethoxysilane, 0.03-0.1 parts of carboxymethyl cellulose and 0.03-0.1 parts of triethyl acetyl citrate.

[0044] In a fourth aspect, there is provided application of the hydrophobic ultra-low density ceramsite sand proppant described in the present invention in oil production.

[0045] Preferably, the preparation method of the hydrophobic ultra-low density ceramsite sand proppant comprises the following steps:

[0046] Step S1. Grinding a powder consisting of red mud, phosphogypsum, coal slag, titanium gypsum and fly ash to obtain a mixed powder;

[0047] Step S2. adding alumina magnetic beads and silica magnetic beads to the mixed powder and grinding them to obtain a magnetic bead mixed powder;

[0048] Step S3. adding a slurry consisting of polyamide, N-(aminoethyl)-aminopropyl triethoxysilane, carboxymethyl cellulose and triethyl acetyl citrate to the magnetic bead mixed powder for grinding to obtain a magnetic bead mixed slurry;

[0049] Step S4. Drying, crushing, screening and granulating the magnetic bead mixed slurry to obtain a semi-finished ceramsite sand;

[0050] Step S5: sintering, cooling and screening the semi-finished ceramsite sand to obtain a hydrophobic ultra-low-density ceramsite sand proppant.

[0051] Preferably, in terms of mass fractions, the powder consists of 30-40 parts of red mud, 6-10 parts of phosphogypsum, 2-4 parts of coal slag, 3-5 parts of titanium gypsum and 20-30 parts of fly ash.

[0052] Preferably, in terms of mass fraction, the powder consists of 30 parts of red mud, 7 parts of phosphogypsum, 3 parts of coal slag, 4 parts of titanium gypsum and 25 parts of fly ash.

[0053] Preferably, the mass ratio of the silica magnetic beads to the total amount of the mixed powder is 8-20%.

[0054] Preferably, the mass ratio of the alumina magnetic beads to the total amount of the mixed powder is 5-10%.

[0055] Preferably, in terms of mass fractions, the slurry consists of 0.1-0.2 parts of polyamide, 0.005-0.008 parts of N-(aminoethyl)-aminopropyltriethoxysilane, 0.03-0.1 parts of carboxymethyl cellulose and 0.03-0.1 parts of triethyl acetyl citrate.

[0056] A fifth aspect provides application of the hydrophobic ultra-low density ceramsite sand proppant described in the present invention in natural gas well exploitation.

[0057] Preferably, the preparation method of the hydrophobic ultra-low density ceramsite sand proppant comprises the following steps:

[0058] Step S1. Grinding a powder consisting of red mud, phosphogypsum, coal slag, titanium gypsum and fly ash to obtain a mixed powder;

[0059] Step S2. adding alumina magnetic beads and silica magnetic beads to the mixed powder and grinding them to obtain a magnetic bead mixed powder;

[0060] Step S3. adding a slurry consisting of polyamide, N-(aminoethyl)-aminopropyl triethoxysilane, carboxymethyl cellulose and triethyl acetyl citrate to the magnetic bead mixed powder for grinding to obtain a magnetic bead mixed slurry;

[0061] Step S4. Drying, crushing, screening and granulating the magnetic bead mixed slurry to obtain a semi-finished ceramsite sand;

[0062] Step S5: sintering, cooling and screening the semi-finished ceramsite sand to obtain a hydrophobic ultra-low-density ceramsite sand proppant.

[0063] Preferably, in terms of mass fractions, the powder consists of 30-40 parts of red mud, 6-10 parts of phosphogypsum, 2-4 parts of coal slag, 3-5 parts of titanium gypsum and 20-30 parts of fly ash.

[0064] Preferably, in terms of mass fraction, the powder consists of 30 parts of red mud, 7 parts of phosphogypsum, 3 parts of coal slag, 4 parts of titanium gypsum and 25 parts of fly ash.

[0065] Preferably, the mass ratio of the silica magnetic beads to the total amount of the mixed powder is 8-20%.

[0066] Preferably, the mass ratio of the alumina magnetic beads to the total amount of the mixed powder is 5-10%.

[0067] Preferably, in terms of mass fractions, the slurry consists of 0.1-0.2 parts of polyamide, 0.005-0.008 parts of N-(aminoethyl)-aminopropyltriethoxysilane, 0.03-0.1 parts of carboxymethyl cellulose and 0.03-0.1 parts of triethyl acetyl citrate.

[0068] Compared with the prior art, the beneficial effects of the present invention are:

[0069] The powder used in the preparation method of the hydrophobic ultra-low-density ceramsite sand proppant provided by the present invention is composed of industrial solid wastes such as red mud, phosphogypsum, coal slag, titanium gypsum and fly ash. The raw material source is wide and can reduce environmental pollution. The hydrophobic ultra-low-density ceramsite sand proppant prepared by the present invention has good hydrophobicity and ultra-low density. Further, the present invention further improves the hydrophobicity of the hydrophobic ultra-low-density ceramsite sand proppant prepared by using the powder of the specific mass fraction of the present invention by optimizing the mass fraction of red mud, phosphogypsum, coal slag, titanium gypsum and fly ash in the powder, and further reduces the density of the hydrophobic ultra-low-density ceramsite sand proppant prepared by using the powder of the specific mass fraction of the present invention.

[0070] As hydrophobic materials, silica and alumina have certain hydrophobicity, but their hydrophobicity will be greatly reduced after firing, and they are not suitable for use as hydrophobic materials for products that need to be fired. The present invention unexpectedly confirms that adding both silica and alumina to the mixed powder in the form of coupled magnetic beads unexpectedly improves the hydrophobicity of the obtained hydrophobic ultra-low-density ceramsite sand proppant after subsequent firing; and by optimizing the mass ratio of silica magnetic beads to the total amount of the mixed powder and optimizing the mass ratio of alumina magnetic beads to the total amount of the mixed powder, the hydrophobicity of the hydrophobic ultra-low-density ceramsite sand proppant is further improved.

[0071] In addition, the present invention proves that adding a slurry composed of polyamide, N-(aminoethyl)-aminopropyl triethoxysilane, carboxymethyl cellulose and triethyl acetyl citrate to the preparation process of hydrophobic ultra-low-density ceramsite sand proppant can reduce the friction and adhesion between raw materials, make it easier to mix raw materials evenly, and weaken the stress between raw materials, thereby further increasing the mobility of raw material molecular chains. At the same time, the mixed powder of the present invention and the silica magnetic beads and alumina magnetic beads of the present invention are used to further improve the hydrophobicity of the hydrophobic ultra-low-density ceramsite sand proppant, and the density of the hydrophobic ultra-low-density ceramsite sand proppant can also be reduced. DETAILED DESCRIPTION

[0072] The present invention will be described in detail below in conjunction with specific implementations and examples, and the advantages and various effects of the present invention will be more clearly presented. It should be understood by those skilled in the art that these specific implementations and examples are used to illustrate the present invention, rather than to limit the present invention.

[0073] Example 1

[0074] This embodiment provides a hydrophobic ultra-low density ceramsite sand proppant, and the preparation method of the hydrophobic ultra-low density ceramsite sand proppant comprises the following steps:

[0075] Step S1. Grind a powder consisting of 30 parts of red mud, 6 parts of phosphogypsum, 2 parts of coal slag, 3 parts of titanium gypsum and 20 parts of fly ash for 5 hours to obtain a mixed powder;

[0076] Step S2. Alumina magnetic beads and silica magnetic beads are added to the mixed powder and ground for 4 hours to obtain a magnetic bead mixed powder, wherein the mass ratio of silica magnetic beads to the total amount of the mixed powder is 8%, and the mass ratio of alumina magnetic beads to the total amount of the mixed powder is 5%;

[0077] Step S3. Add a slurry consisting of 0.1 parts of polyamide, 0.005 parts of N-(aminoethyl)-aminopropyltriethoxysilane, 0.03 parts of carboxymethyl cellulose and 0.03 parts of triethyl acetyl citrate to the magnetic bead mixed powder and grind for 3 hours to obtain a magnetic bead mixed slurry;

[0078] Step S4. Drying, crushing, screening and granulating the magnetic bead mixed slurry to obtain a semi-finished ceramsite sand; specifically, spray drying, crushing and screening the magnetic bead mixed slurry, and then placing it in a BYJ500 pelletizer for granulation;

[0079] Step S5. The ceramsite sand semi-finished product is fired, cooled, and screened to obtain a hydrophobic ultra-low-density ceramsite sand proppant; specifically, the ceramsite sand semi-finished product is placed in a high-temperature box-type electric furnace for firing, slowly heated to 1330° C., and naturally cooled. The cooled sample is screened and sealed for storage to obtain the hydrophobic ultra-low-density ceramsite sand proppant.

[0080] Example 2

[0081] This embodiment provides a hydrophobic ultra-low density ceramsite sand proppant, and the preparation method of the hydrophobic ultra-low density ceramsite sand proppant comprises the following steps:

[0082] Step S1. Grind a powder consisting of 40 parts of red mud, 10 parts of phosphogypsum, 4 parts of coal slag, 5 parts of titanium gypsum and 30 parts of fly ash for 5 hours to obtain a mixed powder;

[0083] Step S2. Alumina magnetic beads and silica magnetic beads are added to the mixed powder and ground for 4 hours to obtain a magnetic bead mixed powder, wherein the mass ratio of silica magnetic beads to the total amount of the mixed powder is 20%, and the mass ratio of alumina magnetic beads to the total amount of the mixed powder is 10%;

[0084] Step S3. Add a slurry consisting of 0.2 parts of polyamide, 0.008 parts of N-(aminoethyl)-aminopropyltriethoxysilane, 0.1 parts of carboxymethyl cellulose and 0.1 parts of triethyl acetyl citrate to the magnetic bead mixed powder and grind for 3 hours to obtain a magnetic bead mixed slurry;

[0085] Step S4. Drying, crushing, screening and granulating the magnetic bead mixed slurry to obtain a semi-finished ceramsite sand; specifically, spray drying, crushing and screening the magnetic bead mixed slurry, and then placing it in a BYJ500 pelletizer for granulation;

[0086] Step S5. The ceramsite sand semi-finished product is fired, cooled, and screened to obtain a hydrophobic ultra-low-density ceramsite sand proppant; specifically, the ceramsite sand semi-finished product is placed in a high-temperature box-type electric furnace for firing, slowly heated to 1330° C., and naturally cooled. The cooled sample is screened and sealed for storage to obtain the hydrophobic ultra-low-density ceramsite sand proppant.

[0087] Example 3

[0088] This embodiment provides a hydrophobic ultra-low density ceramsite sand proppant, and the preparation method of the hydrophobic ultra-low density ceramsite sand proppant comprises the following steps:

[0089] Step S1. Grind a powder consisting of 30 parts of red mud, 7 parts of phosphogypsum, 3 parts of coal slag, 4 parts of titanium gypsum and 25 parts of fly ash for 5 hours to obtain a mixed powder;

[0090] Step S2. Alumina magnetic beads and silica magnetic beads are added to the mixed powder and ground for 4 hours to obtain a magnetic bead mixed powder, wherein the mass ratio of silica magnetic beads to the total amount of the mixed powder is 10%, and the mass ratio of alumina magnetic beads to the total amount of the mixed powder is 6%;

[0091] Step S3. Add a slurry consisting of 0.1 parts of polyamide, 0.005 parts of N-(aminoethyl)-aminopropyltriethoxysilane, 0.03 parts of carboxymethyl cellulose and 0.03 parts of triethyl acetyl citrate to the magnetic bead mixed powder and grind for 3 hours to obtain a magnetic bead mixed slurry;

[0092] Step S4. Drying, crushing, screening and granulating the magnetic bead mixed slurry to obtain a semi-finished ceramsite sand; specifically, spray drying, crushing and screening the magnetic bead mixed slurry, and then placing it in a BYJ500 pelletizer for granulation;

[0093] Step S5. The ceramsite sand semi-finished product is fired, cooled, and screened to obtain a hydrophobic ultra-low-density ceramsite sand proppant; specifically, the ceramsite sand semi-finished product is placed in a high-temperature box-type electric furnace for firing, slowly heated to 1330° C., and naturally cooled. The cooled sample is screened and sealed for storage to obtain the hydrophobic ultra-low-density ceramsite sand proppant.

[0094] Comparative Example 1

[0095] This comparative example provides a hydrophobic ultra-low-density ceramsite sand proppant, and the preparation method of the hydrophobic ultra-low-density ceramsite sand proppant comprises the following steps:

[0096] Step S1. Grind a powder consisting of 30 parts of red mud, 7 parts of phosphogypsum, 3 parts of coal slag, 4 parts of titanium gypsum and 25 parts of fly ash for 5 hours to obtain a mixed powder;

[0097] Step S2. Alumina magnetic beads and silicon dioxide are added to the mixed powder and ground for 4 hours to obtain a magnetic bead mixed powder, wherein the mass ratio of silicon dioxide to the total amount of the mixed powder is 10%, and the mass ratio of alumina magnetic beads to the total amount of the mixed powder is 6%;

[0098] Step S3. Add a slurry consisting of 0.1 parts of polyamide, 0.005 parts of N-(aminoethyl)-aminopropyltriethoxysilane, 0.03 parts of carboxymethyl cellulose and 0.03 parts of triethyl acetyl citrate to the magnetic bead mixed powder and grind for 3 hours to obtain a magnetic bead mixed slurry;

[0099] Step S4. Drying, crushing, screening and granulating the magnetic bead mixed slurry to obtain a semi-finished ceramsite sand; specifically, spray drying, crushing and screening the magnetic bead mixed slurry, and then placing it in a BYJ500 pelletizer for granulation;

[0100] Step S5. The ceramsite sand semi-finished product is fired, cooled, and screened to obtain a hydrophobic ultra-low-density ceramsite sand proppant; specifically, the ceramsite sand semi-finished product is placed in a high-temperature box-type electric furnace for firing, slowly heated to 1330° C., and naturally cooled. The cooled sample is screened and sealed for storage to obtain the hydrophobic ultra-low-density ceramsite sand proppant.

[0101] Comparative Example 2

[0102] This comparative example provides a hydrophobic ultra-low-density ceramsite sand proppant, and the preparation method of the hydrophobic ultra-low-density ceramsite sand proppant comprises the following steps:

[0103] Step S1. Grind a powder consisting of 30 parts of red mud, 7 parts of phosphogypsum, 3 parts of coal slag, 4 parts of titanium gypsum and 25 parts of fly ash for 5 hours to obtain a mixed powder;

[0104] Step S2. Alumina magnetic beads and silica magnetic beads are added to the mixed powder and ground for 4 hours to obtain a magnetic bead mixed powder, wherein the mass ratio of silica magnetic beads to the total amount of the mixed powder is 10%, and the mass ratio of alumina magnetic beads to the total amount of the mixed powder is 4%;

[0105] Step S3. Add a slurry consisting of 0.1 parts of polyamide, 0.005 parts of N-(aminoethyl)-aminopropyltriethoxysilane, 0.03 parts of carboxymethyl cellulose and 0.03 parts of triethyl acetyl citrate to the magnetic bead mixed powder and grind for 3 hours to obtain a magnetic bead mixed slurry;

[0106] Step S4. Drying, crushing, screening and granulating the magnetic bead mixed slurry to obtain a semi-finished ceramsite sand; specifically, spray drying, crushing and screening the magnetic bead mixed slurry, and then placing it in a BYJ500 pelletizer for granulation;

[0107] Step S5. The ceramsite sand semi-finished product is fired, cooled, and screened to obtain a hydrophobic ultra-low-density ceramsite sand proppant; specifically, the ceramsite sand semi-finished product is placed in a high-temperature box-type electric furnace for firing, slowly heated to 1330° C., and naturally cooled. The cooled sample is screened and sealed for storage to obtain the hydrophobic ultra-low-density ceramsite sand proppant.

[0108] Comparative Example 3

[0109] This comparative example provides a hydrophobic ultra-low-density ceramsite sand proppant, and the preparation method of the hydrophobic ultra-low-density ceramsite sand proppant comprises the following steps:

[0110] Step S1. Grind a powder consisting of 30 parts of red mud, 3 parts of coal slag, 4 parts of titanium gypsum and 25 parts of fly ash for 5 hours to obtain a mixed powder;

[0111] Step S2. Alumina magnetic beads and silica magnetic beads are added to the mixed powder and ground for 4 hours to obtain a magnetic bead mixed powder, wherein the mass ratio of silica magnetic beads to the total amount of the mixed powder is 10%, and the mass ratio of alumina magnetic beads to the total amount of the mixed powder is 6%;

[0112] Step S3. Add a slurry consisting of 0.1 parts of polyamide, 0.005 parts of N-(aminoethyl)-aminopropyltriethoxysilane, 0.03 parts of carboxymethyl cellulose and 0.03 parts of triethyl acetyl citrate to the magnetic bead mixed powder and grind for 3 hours to obtain a magnetic bead mixed slurry;

[0113] Step S4. Drying, crushing, screening and granulating the magnetic bead mixed slurry to obtain a semi-finished ceramsite sand; specifically, spray drying, crushing and screening the magnetic bead mixed slurry, and then placing it in a BYJ500 pelletizer for granulation;

[0114] Step S5. The ceramsite sand semi-finished product is fired, cooled, and screened to obtain a hydrophobic ultra-low-density ceramsite sand proppant; specifically, the ceramsite sand semi-finished product is placed in a high-temperature box-type electric furnace for firing, slowly heated to 1330° C., and naturally cooled. The cooled sample is screened and sealed for storage to obtain the hydrophobic ultra-low-density ceramsite sand proppant.

[0115] Experiment 1

[0116] The hydrophobic ultra-low density ceramsite sand proppant was prepared into daily-use ceramics (the hydrophobic ultra-low density ceramsite sand proppant was slurry-molded into a ceramic body, the ceramic body was dried, and then fired to form a dense ceramic body). The water absorption rate of the hydrophobic ultra-low density ceramsite sand proppant was evaluated according to GB / T 3299-2011. The experimental results are shown in Table 1.

[0117] Table 1 Experimental results of water absorption rate of hydrophobic ultra-low density ceramsite sand proppant

[0118]

[0119] Similarly, in order to further illustrate the beneficial effects of the present invention, the following comparative examples are provided:

[0120] A comparative example 1.1 is provided. Compared with Example 3, the difference of the comparative example 1.1 is that the carboxymethyl cellulose of the present invention is replaced by dioctyl adipate;

[0121] Comparative Example 1.2 is provided. Compared with Example 3, the difference of Comparative Example 1.2 is that the acetyl citrate triethyl ester of the present invention is replaced by dioctyl adipate;

[0122] Comparative Example 1.3 is provided. Compared with Example 3, the difference of Comparative Example 1.3 is that the N-(aminoethyl)-aminopropyltriethoxysilane of the present invention is replaced by sodium tetrapropylene benzene sulfonate;

[0123] A comparative example 1.4 is provided. Compared with Example 3, the difference of the comparative example 1.4 is that the fly ash of the present invention is replaced with kaolin;

[0124] The hydrophobic ultra-low density ceramsite sand proppant was prepared by the preparation method of the present invention, and tested according to the test method in Experiment 1. The water absorption rate of the hydrophobic ultra-low density ceramsite sand proppant prepared in Comparative Example 1.1, Comparative Example 1.2, Comparative Example 1.3, and Comparative Example 1.4 was observed. The results were similar to those in Comparative Example 1 above.

[0125] Similarly, in order to further illustrate the beneficial effects of the present invention, the following comparative examples are provided:

[0126] A comparative example 2.1 is provided. Compared with Example 3, the difference of the comparative example 2.1 is that: the mass ratio of the alumina magnetic beads to the total amount of the mixed powder is 11%;

[0127] A comparative example 2.2 is provided. Compared with Example 3, the difference of the comparative example 2.2 is that the mass ratio of the silica magnetic beads to the total amount of the mixed powder is 6% or 22%;

[0128] A comparative example 2.3 is provided. Compared with Example 3, the difference of the comparative example 2.3 is that: the mass fraction of phosphogypsum is adjusted to 5 or 11; the mass fraction of titanium gypsum is adjusted to 2 or 6; the mass fraction of red mud is adjusted to 28 or 41; the mass fraction of coal slag is adjusted to 1 or 5; the mass fraction of fly ash is adjusted to 18 or 32;

[0129] A comparative example 2.4 is provided. Compared with Example 3, the difference of the comparative example 2.4 is that the mass fraction of the polyamide is adjusted to 0.05 or 0.3;

[0130] A comparative example 2.5 is provided. Compared with Example 3, the difference of the comparative example 2.5 is that: the mass fraction of N-(aminoethyl)-aminopropyltriethoxysilane is adjusted to 0.004 or 0.009; the mass fraction of acetyl citrate triethyl is adjusted to 0.02 or 0.2;

[0131] A comparative example 2.6 is provided. Compared with Example 3, the difference of the comparative example 2.6 is that the mass fraction of carboxymethyl cellulose is adjusted to 0.02 or 0.3;

[0132] The hydrophobic ultra-low density ceramsite sand proppant was prepared by the preparation method of the present invention, and tested according to the test method in Experiment 1. The water absorption rate of the hydrophobic ultra-low density ceramsite sand proppant prepared in Comparative Example 2.1, Comparative Example 2.2, Comparative Example 2.3, Comparative Example 2.4, Comparative Example 2.5, and Comparative Example 2.6 was observed. The results were similar to those in Comparative Example 2 above.

[0133] Similarly, in order to further illustrate the beneficial effects of the present invention, the following comparative examples are provided:

[0134] A comparative example 3.1 is provided. Compared with Example 3, the difference of the comparative example 3.1 is that: no red mud is added;

[0135] A comparative example 3.2 is provided. Compared with Example 3, the difference of the comparative example 3.2 is that: no phosphogypsum is added;

[0136] A comparative example 3.3 is provided. Compared with Example 3, the difference of the comparative example 3.3 is that: fly ash is not added;

[0137] A comparative example 3.4 is provided. Compared with Example 3, the difference of the comparative example 3.4 is that: no polyamide is added;

[0138] Comparative Example 3.5 is provided. Compared with Example 3, the difference of Comparative Example 3.5 is that: N-(aminoethyl)-aminopropyltriethoxysilane is not added;

[0139] A comparative example 3.6 is provided. Compared with Example 3, the difference of comparative example 3.6 is that no carboxymethyl cellulose is added.

[0140] The hydrophobic ultra-low density ceramsite sand proppant was prepared by the preparation method of the present invention, and tested according to the test method in Experiment 1. The water absorption rate of the hydrophobic ultra-low density ceramsite sand proppant prepared in Comparative Example 3.1, Comparative Example 3.2, Comparative Example 3.3, Comparative Example 3.4, Comparative Example 3.5, and Comparative Example 3.6 was observed. The results were similar to those in Comparative Example 3 above.

[0141] As can be seen from Table 1, the water absorption rate of daily-use ceramics prepared by the hydrophobic ultra-low density ceramsite sand proppant prepared by the method of the present invention is lower, all less than 12.50%, specifically 11.33-12.45%; and the water absorption rate of daily-use ceramics prepared by the hydrophobic ultra-low density ceramsite sand proppant obtained in Example 3 is the lowest, specifically 11.33%; this also shows that the hydrophobic ultra-low density ceramsite sand proppant prepared by the method of the present invention has better hydrophobicity, and the hydrophobic ultra-low density ceramsite sand proppant obtained in Example 3 has the best hydrophobicity. The water absorption rate of the hydrophobic ultra-low density ceramsite sand proppant not prepared by the method of the present invention is higher, specifically 23.28-24.95%. The high water absorption rate will increase the weight of the ceramsite, thereby increasing the difficulty of pumping and the cost of fracturing, and cannot meet the use requirements of oil and natural gas extraction.

[0142] Experiment 2

[0143] The density of the hydrophobic ultra-low density ceramsite sand proppant was evaluated according to Q / SY 124-2007 and SY / T 5108-2006. The experimental results are shown in Table 2.

[0144] Table 2 Density test results of hydrophobic ultra-low density ceramsite sand proppant

[0145]

[0146] Similarly, in order to further illustrate the beneficial effects of the present invention, the following comparative examples are provided:

[0147] A comparative example 1.1 is provided. Compared with Example 3, the difference of the comparative example 1.1 is that the carboxymethyl cellulose of the present invention is replaced by dioctyl adipate;

[0148] Comparative Example 1.2 is provided. Compared with Example 3, the difference of Comparative Example 1.2 is that the acetyl citrate triethyl ester of the present invention is replaced by dioctyl adipate;

[0149] Comparative Example 1.3 is provided. Compared with Example 3, the difference of Comparative Example 1.3 is that the N-(aminoethyl)-aminopropyltriethoxysilane of the present invention is replaced by sodium tetrapropylene benzene sulfonate;

[0150] A comparative example 1.4 is provided. Compared with Example 3, the difference of the comparative example 1.4 is that the fly ash of the present invention is replaced with kaolin;

[0151] The hydrophobic ultra-low density ceramsite sand proppant was prepared by the preparation method of the present invention, and tested according to the test method in Experiment 2. The density of the hydrophobic ultra-low density ceramsite sand proppant prepared in Comparative Example 1.1, Comparative Example 1.2, Comparative Example 1.3, and Comparative Example 1.4 was observed. The results were similar to those in Comparative Example 1 above.

[0152] Similarly, in order to further illustrate the beneficial effects of the present invention, the following comparative examples are provided:

[0153] A comparative example 2.1 is provided. Compared with Example 3, the difference of the comparative example 2.1 is that: the mass ratio of the alumina magnetic beads to the total amount of the mixed powder is 11%;

[0154] A comparative example 2.2 is provided. Compared with Example 3, the difference of the comparative example 2.2 is that the mass ratio of the silica magnetic beads to the total amount of the mixed powder is 6% or 22%;

[0155] A comparative example 2.3 is provided. Compared with Example 3, the difference of the comparative example 2.3 is that: the mass fraction of phosphogypsum is adjusted to 5 or 11; the mass fraction of titanium gypsum is adjusted to 2 or 6; the mass fraction of red mud is adjusted to 28 or 41; the mass fraction of coal slag is adjusted to 1 or 5; the mass fraction of fly ash is adjusted to 18 or 32;

[0156] A comparative example 2.4 is provided. Compared with Example 3, the difference of the comparative example 2.4 is that the mass fraction of the polyamide is adjusted to 0.05 or 0.3;

[0157] A comparative example 2.5 is provided. Compared with Example 3, the difference of the comparative example 2.5 is that: the mass fraction of N-(aminoethyl)-aminopropyltriethoxysilane is adjusted to 0.004 or 0.009; the mass fraction of acetyl citrate triethyl is adjusted to 0.02 or 0.2;

[0158] A comparative example 2.6 is provided. Compared with Example 3, the difference of the comparative example 2.6 is that the mass fraction of carboxymethyl cellulose is adjusted to 0.02 or 0.3;

[0159] The hydrophobic ultra-low density ceramsite sand proppant was prepared by the preparation method of the present invention, and tested according to the test method in Experiment 2. The density of the hydrophobic ultra-low density ceramsite sand proppant prepared in Comparative Example 2.1, Comparative Example 2.2, Comparative Example 2.3, Comparative Example 2.4, Comparative Example 2.5, and Comparative Example 2.6 was observed. The results were similar to those in Comparative Example 2 above.

[0160] Similarly, in order to further illustrate the beneficial effects of the present invention, the following comparative examples are provided:

[0161] A comparative example 3.1 is provided. Compared with Example 3, the difference of the comparative example 3.1 is that: no red mud is added;

[0162] A comparative example 3.2 is provided. Compared with Example 3, the difference of the comparative example 3.2 is that: no phosphogypsum is added;

[0163] A comparative example 3.3 is provided. Compared with Example 3, the difference of the comparative example 3.3 is that: fly ash is not added;

[0164] A comparative example 3.4 is provided. Compared with Example 3, the difference of the comparative example 3.4 is that: no polyamide is added;

[0165] Comparative Example 3.5 is provided. Compared with Example 3, the difference of Comparative Example 3.5 is that: N-(aminoethyl)-aminopropyltriethoxysilane is not added;

[0166] A comparative example 3.6 is provided. Compared with Example 3, the difference of comparative example 3.6 is that no carboxymethyl cellulose is added.

[0167] The hydrophobic ultra-low density ceramsite sand proppant was prepared by the preparation method of the present invention, and tested according to the test method in Experiment 2. The density of the hydrophobic ultra-low density ceramsite sand proppant prepared in Comparative Example 3.1, Comparative Example 3.2, Comparative Example 3.3, Comparative Example 3.4, Comparative Example 3.5, and Comparative Example 3.6 was observed. The results were similar to those in Comparative Example 3 above.

[0168] It can be seen from Table 2 that the method of the present invention can effectively reduce the density of the ultra-low density ceramsite sand proppant, and the hydrophobic ultra-low density ceramsite sand proppant obtained in Example 3 has the lowest density, while the hydrophobic ultra-low density ceramsite sand proppant prepared without the method of the present invention has a relatively large density and cannot well meet the use requirements of oil and natural gas extraction.

[0169] Experiment 3

[0170] The hydrophobic ultra-low density ceramsite sand proppant prepared in Example 3 was subjected to component analysis, and the experimental results are shown in Table 3.

[0171] Table 3 Composition analysis results of the hydrophobic ultra-low density ceramsite sand proppant prepared in Example 3

[0172]

[0173] As can be seen from Table 3, by analyzing the components of the hydrophobic ultra-low density ceramsite sand proppant prepared in Example 3 of the present invention, it can be seen that the main components of the hydrophobic ultra-low density ceramsite sand proppant prepared in Example 3 of the present invention are Al2O3, SiO2 and Fe2O3, which meets the requirements of the aluminum-silicon-iron ternary system in the field of ceramsite sand proppants, and the hydrophobic ultra-low density ceramsite sand proppant prepared in Example 3 of the present invention has very few impurities. The present invention effectively controls the types and contents of impurities introduced in the preparation process of the hydrophobic ultra-low density ceramsite sand proppant. Specifically, the controlled amount of impurity calcium in the hydrophobic ultra-low density ceramsite sand proppant prepared in Example 3 of the present invention is 0.49%, and the controlled amount of impurity sodium is 0.07%.

[0174] In addition, through component analysis of the hydrophobic ultra-low density ceramsite sand proppant prepared in Example 1 and Example 2 of the present invention, it can be known that the main components of the hydrophobic ultra-low density ceramsite sand proppant prepared in Example 1 and Example 2 of the present invention are Al2O3, SiO2 and Fe2O3, which also meets the requirements of the aluminum-silicon-iron ternary system in the field of ceramsite sand proppants.

[0175] It should be understood that the disclosed invention is not limited only to the specific method, scheme and material of description, because these all can change.It should also be understood that the terminology used herein is only for the purpose of describing specific embodiment scheme, rather than being intended to limit the scope of the present invention, and the scope of the present invention is only limited to the appended claims.

[0176] Those skilled in the art will also recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are also intended to be encompassed by the appended claims.

Claims

1. A method for preparing a hydrophobic ultra-low density ceramsite sand proppant, characterized in that: The following steps are involved: Step S1. Grinding a powder consisting of red mud, phosphogypsum, coal slag, titanium gypsum and fly ash to obtain a mixed powder; Step S2. adding alumina-coupled magnetic beads and silica-coupled magnetic beads to the mixed powder and grinding them to obtain a mixed powder of magnetic beads; Step S3. adding a slurry consisting of polyamide, N-(aminoethyl)-aminopropyl triethoxysilane, carboxymethyl cellulose and triethyl acetyl citrate to the magnetic bead mixed powder for grinding to obtain a magnetic bead mixed slurry; Step S4. Drying, crushing, screening and granulating the magnetic bead mixed slurry to obtain a semi-finished ceramsite sand; Step S5. sintering, cooling, and screening the semi-finished ceramsite sand to obtain a hydrophobic ultra-low-density ceramsite sand proppant; In terms of mass fraction, the powder consists of 30-40 parts of red mud, 6-10 parts of phosphogypsum, 2-4 parts of coal slag, 3-5 parts of titanium gypsum and 20-30 parts of fly ash; The mass ratio of the alumina coupled magnetic beads to the total amount of the mixed powder is 5-10%; The mass ratio of the silica coupled magnetic beads to the total amount of the mixed powder is 8-20%; In terms of mass fractions, the slurry consists of 0.1-0.2 parts of polyamide, 0.005-0.008 parts of N-(aminoethyl)-aminopropyltriethoxysilane, 0.03-0.1 parts of carboxymethyl cellulose and 0.03-0.1 parts of triethyl acetyl citrate.

2. The preparation method according to claim 1, characterized in that: In terms of mass percentage, the powder consists of 30 parts of red mud, 7 parts of phosphogypsum, 3 parts of coal slag, 4 parts of titanium gypsum and 25 parts of fly ash.

3. A hydrophobic ultra-low density ceramsite sand proppant, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 2.

4. A fracturing proppant, characterized in that: It includes the hydrophobic ultra-low density ceramsite sand proppant as described in claim 3.

5. Use of the hydrophobic ultra-low density ceramsite sand proppant according to claim 3 in oil production.

6. Use of the hydrophobic ultra-low density ceramsite sand proppant according to claim 3 in natural gas well production.

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