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CN-122012069-A - Preparation method of quartz sand for high-strength fracturing

CN122012069ACN 122012069 ACN122012069 ACN 122012069ACN-122012069-A

Abstract

The invention discloses a preparation method of quartz sand for high-strength fracturing, which comprises the steps of cleaning, dehydrating, ball milling and secondary modification of quartz sand, wherein the modification comprises polymerization modification and surface modification, the polymerization modification modifier comprises vinyl triethoxysilane, sodium stearate, 1% sodium hydroxide solution, phenolic resin and titanate, the surface modification modifier is cetyl trimethyl ammonium bromide, and the roundness, sphericity, surface smoothness, microstructure and other properties of the quartz fracturing sand are improved, so that the technical problems of lower strength and poorer crushing resistance of the quartz fracturing sand are solved.

Inventors

  • HU LEI
  • HUANG HE

Assignees

  • 贵州子垚硅业科技有限公司

Dates

Publication Date
20260512
Application Date
20251224

Claims (10)

  1. 1. The preparation method of the quartz sand for high-strength fracturing is characterized by comprising the following steps of: (1) Washing, namely washing quartz sand for the first time by adopting a cylindrical sand washing screening machine, carrying out magnetic separation after washing, then transferring into a scrubbing machine, adding acid for pickling, and finally carrying out washing for the second time to obtain the quartz sand after washing for later use; (2) Dewatering and drying, namely transferring the cleaned quartz sand into a dewatering screen for dewatering for 10-20 minutes, and drying by a dryer for 30-60 minutes at 150-250 ℃ for later use; (3) Ball milling and screening, namely transferring the dried quartz sand into a wet ball mill, adding an auxiliary agent for ball milling, and grading and screening after ball milling to obtain quartz sand powder with the particle size within the range of 0.4-0.8 mm; (4) Heating quartz sand powder to 180-250 ℃, spraying a modifier, and uniformly mixing, wherein the mass ratio of the quartz sand powder to the modifier is 1:2-4, and stirring at a high speed for 1-2h under the condition of 180-250 ℃ to obtain primary modified quartz sand; The modifier comprises vinyl triethoxysilane, sodium stearate, 1% sodium hydroxide solution, phenolic resin and titanate, wherein the mass ratio of the vinyl triethoxysilane to the sodium stearate to the 1% sodium hydroxide solution to the phenolic resin to the titanate is 4-7:1-3:2-4:1-3:0.5-1.5; (5) Secondary surface modification, namely reducing the temperature of the primary modified quartz sand to 120-150 ℃, adding hexadecyl trimethyl ammonium bromide for mixing, and stirring at a high speed for 2-4 hours under the condition of 120-150 ℃ to obtain secondary modified quartz sand; The mass ratio of the primary modified quartz sand to the cetyl trimethyl ammonium bromide is 1:1.5; (6) Sintering, namely sintering the secondary modified quartz sand for 0.5-1.5 hours at the temperature of 450-500 ℃ to obtain the quartz sand for high-strength fracturing.
  2. 2. The method of producing silica sand for high strength fracturing according to claim 1, wherein in the step (1), the acid washing is performed by using a 1% hydrochloric acid solution and a 3% hydrofluoric acid solution, and the mass ratio of the 1% hydrochloric acid solution to the 3% hydrofluoric acid solution is 1:2.
  3. 3. The method for preparing high-strength silica sand for fracturing according to claim 1, wherein in the step (2), the drying time is 45-50 minutes, and the drying temperature is 190-210 ℃.
  4. 4. The method for preparing the quartz sand for high-strength fracturing according to claim 1, wherein in the step (3), the auxiliary agent added by ball milling is triethanolamine, and the mass ratio of the quartz sand to the balls to the triethanolamine is 1:2:0.3.
  5. 5. The method of producing silica sand for high strength fracturing according to claim 1, wherein in the step (4), the mass ratio of the silica sand powder to the modifier is 1:3.
  6. 6. The method of preparing silica sand for high strength fracturing according to claim 1, wherein in the step (4), the modifier comprises vinyltriethoxysilane, sodium stearate, 1% sodium hydroxide solution, phenolic resin and titanate, and the mass ratio of vinyltriethoxysilane, sodium stearate, 1% sodium hydroxide solution, phenolic resin and titanate is 5:2:3:2:1.
  7. 7. The method for preparing the quartz sand for high-strength fracturing according to claim 1 or 6, wherein in the step (4), the modifier is prepared by adding vinyltriethoxysilane and sodium stearate into a 1% sodium hydroxide solution, heating and mixing for 10-20min, wherein the heating temperature is 55-65 ℃, and uniformly mixing, then heating phenolic resin and titanate, and uniformly stirring.
  8. 8. The method of producing silica sand for high strength fracturing according to claim 1, wherein in the step (4), the stirring speed is 10-100r/min.
  9. 9. The method of producing a high strength silica sand for fracturing according to claim 1, wherein in the step (5), the mass ratio of the primary modified silica sand to cetyltrimethylammonium bromide is 1:1.5.
  10. 10. The method of producing silica sand for high strength fracturing according to claim 1, wherein in the step (5), the stirring speed is 10 to 100r/min.

Description

Preparation method of quartz sand for high-strength fracturing Technical Field The invention relates to the technical field of quartz sand production, in particular to a preparation method of quartz sand for high-strength fracturing. Background With the development of petroleum industry and the progress of scientific technology, the hydraulic fracturing technology process becomes an important measure for increasing the yield of land low permeability oil fields, in the hydraulic fracturing technology process, the selection of propping agent is crucial, and the commonly used propping agent is quartz fracturing sand. The quartz fracturing sand is prepared by a plurality of working procedures from exploitation to oil field acquisition, wherein the usage amount of the quartz fracturing sand is the first in the production of oil fields at home and abroad with low price and good use performance. At present, many domestic quartz fracturing sand has lower strength and poorer breaking resistance, the breaking rate of the quartz sand propping agent is more than 8% under the closing pressure of 28 megapascals, and the higher breaking rate reduces the fracturing yield increasing effect of the quartz sand applied to oil and gas wells. Along with the rapid development of hydraulic fracturing technology, the demand of fracturing propping agents is rapidly increased, high-purity and high-strength quartz sand is greatly demanded, and the current quartz fracturing sand cannot meet the use requirements of oil fields. The invention improves the performance requirements of roundness, sphericity, surface finish, microstructure and the like of the quartz fracturing sand by cleaning, dehydrating, ball milling and secondary modification of the quartz sand. Therefore, the technical problems of low strength and poor breaking resistance of quartz fracturing sand are solved. Disclosure of Invention The invention aims to provide a preparation method of quartz sand for high-strength fracturing, which aims to solve the technical problems of low strength and poor breaking resistance of quartz fracturing sand. In order to solve the technical problems, the invention is realized by adopting the following technical scheme: 1. the preparation method of the quartz sand for high-strength fracturing comprises the following steps: (1) Washing, namely washing quartz sand for the first time by adopting a cylindrical sand washing screening machine, carrying out magnetic separation after washing, then transferring into a scrubbing machine, adding acid for pickling, and finally carrying out washing for the second time to obtain the quartz sand after washing for later use; (2) Dewatering and drying, namely transferring the cleaned quartz sand into a dewatering screen for dewatering for 10-20 minutes, and drying by a dryer for 30-60 minutes at 150-250 ℃ for later use; (3) Ball milling and screening, namely transferring the dried quartz sand into a wet ball mill, adding an auxiliary agent for ball milling, and grading and screening after ball milling to obtain quartz sand powder with the particle size within the range of 0.4-0.8 mm; (4) The primary polymerization modification, namely heating quartz sand powder to 180-250 ℃, spraying a modifier, uniformly mixing, and stirring at a high speed for 1-2h under the condition of 180-250 ℃ to obtain primary modified quartz sand; The modifier comprises vinyl triethoxysilane, sodium stearate, 1% sodium hydroxide solution, phenolic resin and titanate, wherein the mass ratio of the vinyl triethoxysilane to the sodium stearate to the 1% sodium hydroxide solution to the phenolic resin to the titanate is 4-7:1-3:2-4:1-3:0.5-1.5; (5) Secondary surface modification, namely reducing the temperature of the primary modified quartz sand to 120-150 ℃, adding hexadecyl trimethyl ammonium bromide for mixing, and stirring at a high speed for 2-4 hours under the condition of 120-150 ℃ to obtain secondary modified quartz sand; The mass ratio of the primary modified quartz sand to the cetyl trimethyl ammonium bromide is 1:1.5; (6) Sintering, namely sintering the secondary modified quartz sand for 0.5-1.5 hours at the temperature of 450-500 ℃ to obtain the quartz sand for high-strength fracturing. In the step (1), the pickling is performed by using a 1% hydrochloric acid solution and a 3% hydrofluoric acid solution, wherein the mass ratio of the 1% hydrochloric acid solution to the 3% hydrofluoric acid solution is 1:2. In the step (2), the drying time is 45-50 minutes, and the drying temperature is 190-210 ℃. In the step (3), the auxiliary agent added in the ball milling is triethanolamine, and the mass ratio of quartz sand to balls to triethanolamine is 1:2:0.3. In the step (4), the mass ratio of the quartz sand powder to the modifier is 1:3. In the step (4), the modifier comprises vinyltriethoxysilane, sodium stearate, 1% sodium hydroxide solution, phenolic resin and titanate, wherein the mass ratio of the vinyltriethoxysilane to the