# US 9,434,874 B2 · Hydrophobic proppant and preparation method thereof

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- Number: US 9,434,874 B2
- Document ID: US9434874B2
- Status: Granted
- Kind: B2
- Application number: 13/877,243
- Filed: 2011-09-14
- Published: 2013-08-29
- Granted: 2016-09-06
- Earliest claimed: 2010-09-30
- Assignees: Beijing Rechsand Sand Industry Science & Technology Co., Ltd
- Applicants: Shengyi Qin; Baoling Hu
- Inventors: Shengyi Qin; Baoling Hu
- Web page: https://patentgrep.com/patent/US9434874B2

## CPC

- C09K 8/805: {Coated proppants}
- C09K 8/62: Compositions for forming crevices or fractures
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE

## Abstract

The invention discloses a hydrophobic proppant and a preparation method thereof. The aggregate particles of the hydrophobic proppant are coated with a coating resin which comprises a hydrophobic resin and nano-particles which are uniformly distributed in the coating resin and constitute 5-60% of the coating resin by weight. The contact angle labeled as θ between water and the hydrophobic proppant in which nano-particles are added is in the range of 120°≦θ≦180°. The proppant of the present invention is prepared by adding the nano-particles in the existing resin in which low-surface-energy substances with hydrophobic groups are added, and a rough surface with a micro-nano structure is constructed on the outer surface of the prepared resin film, so that the contact angle θ at the solid-liquid contact surface on the outer surface of the coating resin of the proppant is more than 120°.

## Claims

### Claim 1

A hydrophobic proppant, comprising:
aggregate particles; and
a coating resin cured on the surface of the aggregate particles, the coating resin comprising:
a hydrophobic resin, and
nanoparticles uniformly distributed throughout the hydrophobic resin;
wherein:
the nanoparticles constitute 5 to 60% of the coating resin by weight;
a weight ratio of the aggregate particles to the coating resin is 60-95:3-30; and
the proppant has a contact angle of θ in the range of 120°≦θ≦180°.

### Claim 2 (depends on 1)

The hydrophobic proppant of claim 1, wherein:
the nanoparticles are selected from the group consisting of nano-silicon dioxide, nano-aluminum oxide, nano-zinc oxide, nano-calcium carbonate, and mixtures thereof.

### Claim 3 (depends on 1)

The hydrophobic proppant of claim 1, wherein:
the nanoparticles have a particle size in a range of 50 nm to 150 nm.

### Claim 4 (depends on 1)

The hydrophobic proppant of claim 1, further comprising a silane coupling agent, wherein a weight ratio of the silane coupling agent to the coating resin is 0.1-1:100.

### Claim 5 (depends on 1)

The hydrophobic proppant of claim 1, wherein:
the hydrophobic resin is obtained by modifying a resin with an organic silicon compound or a fluorine-containing compound, and
a side chain of the organic silicon compound or of the fluorine-containing compound is a hydrophobic group.

### Claim 6 (depends on 5)

The hydrophobic proppant of claim 5, wherein:
the organic silicon compound is selected from the group consisting of tricarboxylic polydiphenylsiloxane, α,ω-dihydroxy polydimethylsiloxane, triamino polydimethylsiloxane, polysiloxane triol, tricarboxylic polydimethylsiloxane, tricarboxylic silyloxy-methyl silasesquioxane, and mixtures thereof; and
the fluorine-containing compound is selected from the group consisting of tetrafluoroethylene, vinylidene fluoride, chlorotrifluoroethylene, fluorocarboxylic acid, and mixtures thereof.

### Claim 7 (depends on 6)

The hydrophobic proppant of claim 6, wherein:
the hydrophobic group of the side chain has a structural formula as follows:
wherein:
R1 and R2 are selected from the group consisting of amino, hydroxy, carboxy and alkoxy;
R3 and R4 are selected from the group consisting of alkyl and aryl; and
n is an integer in a range of 4 to 200.

### Claim 8 (depends on 4)

The hydrophobic proppant of claim 4, wherein:
the silane coupling agent is selected from the group consisting of γ-aminopropyltriethoxysilane, γ-(2,3-glycidoxy) propyl trimethoxysilane, γ-(methacryloyloxy) propyl trimethoxysilane, N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane, vinyl tris(β-methoxyethoxy) silane, and mixtures thereof.

### Claim 9 (depends on 1)

A preparation method of the hydrophobic proppant of claim 1, comprising the following steps:
1) heating a hydrophobic resin to a molten state, adding nanoparticles, stirring and cooling to room temperature, obtaining a coating resin comprising the nanoparticles which are uniformly distributed in the hydrophobic resin;
2) heating aggregate particles, adding the coating resin prepared in step 1) and a silane coupling agent, and stirring for 10 to 60 seconds to uniformly coat the coating resin onto surfaces of the aggregate particles; and
3) curing the coating resin.

### Claim 10 (depends on 9)

The preparation method of claim 9, wherein:
in step 3), curing the coating resin comprises adding a curing agent to the coating resin.

### Claim 11 (depends on 10)

The preparation method of claim 10, wherein:
the curing agent is selected from the group consisting of paraformaldehyde, hexamethylene tetramine, aliphatic amine, tertiary amine and salts thereof, aromatic amine and modified products thereof, imidazole, macromolecule prepolymer, acyl peroxide, peroxyester, and mixtures thereof;
and a weight ratio of the curing agent to the coating resin is 1-20:100.

### Claim 12 (depends on 9)

The preparation method of claim 9, further comprising the following step after step 3):
4) adding a lubricating agent, stirring uniformly, cooling and screening.

### Claim 13 (depends on 12)

The preparation method of claim 12, wherein:
the lubricating agent is selected from the group consisting of polyethylene wax, oxidized polyethylene wax, stearic amide, calcium stearate, and mixtures thereof; and
a weight ratio of the lubricating agent to the coating resin is 0.5-3:100.

### Claim 14 (depends on 9)

The preparation method of claim 9, wherein:
in step 1), the stirring is performed for 30 minutes under 8000r.

### Claim 15 (depends on 9)

The preparation method of claim 9, wherein:
in step 2), the aggregate particles are heated to a temperature in a range of 200 to 220° C.