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CN-122011294-A - Polyacrylamide thickener based on tung oil, and preparation method and application thereof

CN122011294ACN 122011294 ACN122011294 ACN 122011294ACN-122011294-A

Abstract

The invention discloses a preparation method of a tung oil-based polyacrylamide thickener, which comprises the steps of firstly adding a polymerization monomer into a reaction vessel added with water, stirring until the polymerization monomer is completely dissolved, regulating a pH value to obtain a polymerization solution, secondly adding a composite initiator into the polymerization solution, heating the polymerization solution to initiate free radical polymerization, introducing nitrogen into the polymerization solution to remove dissolved oxygen, sealing the reaction vessel after the nitrogen is introduced into the polymerization solution to complete the reaction, carrying out constant-temperature reaction to obtain polymer gel, and thirdly, sequentially granulating, drying, crushing and sieving the polymer gel to obtain the polyacrylamide thickener. According to the tung oil-based polyacrylamide thickener, the preparation method and the application, the polymer molecular chain segment is not easy to shrink and curl, so that the salt resistance and the temperature resistance thickening performance of the polyacrylamide thickener are enhanced.

Inventors

  • LV BIN
  • Ni Qinggang
  • GAO DANGGE
  • YANG XU
  • Cheng Dongmiao

Assignees

  • 陕西科技大学

Dates

Publication Date
20260512
Application Date
20260228

Claims (10)

  1. 1. The preparation method of the tung oil-based polyacrylamide thickener is characterized by comprising the following steps of: step one, adding a polymerization monomer into a reaction container added with water, stirring until the polymerization monomer is completely dissolved, and regulating the pH value to 6.5-7.5 to obtain a polymerization solution; Step two, adding a composite initiator into a polymerization solution, heating the polymerization solution to 40-60 o ℃ to initiate free radical polymerization, introducing nitrogen with the purity of 99.99% into the polymerization solution to remove dissolved oxygen, stopping introducing nitrogen, sealing a reaction container, and reacting at constant temperature to obtain polymer gel; And thirdly, granulating, drying, crushing and sieving the polymer gel in sequence to obtain the tung oil-based polyacrylamide thickener.
  2. 2. The method for preparing the tung oil-based polyacrylamide thickener according to claim 1, wherein the polymerization monomer comprises 70-80 parts of acrylamide, 5-8 parts of tung oil, 5-15 parts of 2-acrylamide-2-methylpropanesulfonic acid and 5-8 parts of tween 80 by total mass of the polymerization monomer.
  3. 3. The method for preparing the tung oil-based polyacrylamide thickener according to claim 1, wherein the total mass of the polymerized monomer and water is 20-30 parts.
  4. 4. The preparation method of the tung oil-based polyacrylamide thickener according to claim 1 is characterized in that nitrogen with the purity of 99.99% is introduced into a polymerization solution in the second step, the introduction rate is 50-70 mL/min, the introduction mode is that the nitrogen goes deep below the liquid level of the polymerization solution, the nitrogen introduction time is 30 min, after the nitrogen introduction is completed, a reaction vessel is sealed, the temperature of the constant-temperature reaction is 40- o ℃, and the time of the constant-temperature reaction is 10-14 h.
  5. 5. The preparation method of the tung oil-based polyacrylamide thickener according to claim 1, wherein the composite initiator is formed by compounding an oxidation initiator, a reduction initiator and an azo initiator, the mass ratio of the oxidation initiator to the reduction initiator to the azo initiator is 1:1:1, and the addition amount of the composite initiator is 0.06 part of the total mass of polymerized monomers.
  6. 6. The method for preparing the tung oil-based polyacrylamide thickener according to claim 5, wherein the oxidation initiator is potassium persulfate or ammonium persulfate, the reduction initiator is sodium bisulfite or sodium ascorbate, and the azo initiator is AIBN or V 50 .
  7. 7. The method for preparing a tung oil-based polyacrylamide thickener according to claim 1, wherein the temperature of the drying in the third step is 50 o C、60 o C or 70 o C.
  8. 8. The method for preparing the tung oil-based polyacrylamide thickener according to claim 1, wherein in the step three, the granulation mode is cutting by scissors, the particle size of gel particles is 0.2-0.5 cm, the drying time is 48-72 h, and the sieving is carried out by adopting a 200-mesh screen.
  9. 9. The tung oil-based polyacrylamide thickener prepared by the method for preparing the tung oil-based polyacrylamide thickener according to any one of claims 1-8.
  10. 10. Use of the tung oil based polyacrylamide thickener according to claim 9 in thickening oil and gas field fracturing fluids.

Description

Polyacrylamide thickener based on tung oil, and preparation method and application thereof Technical Field The invention belongs to the technical field of oilfield chemical auxiliary materials, and particularly relates to a tung oil-based polyacrylamide thickener, and a preparation method and application of the tung oil-based polyacrylamide thickener. Background The tung oil molecular structure contains double bonds and glyceride group structures, the double bonds of the tung oil molecular structure can be polymerized with acrylamide in a free radical manner to form a chemical crosslinking network, the movement of polymer molecular chain segments can be limited, the shearing stability of the polymer network can be effectively improved, and the thickening performance of the thickener under the conditions of high salt, high temperature and dynamic shearing can be improved. The polyacrylamide thickener is widely applied to various large oil fields in China and is a key component of an oil and gas field fracturing fluid system. The high-salt and high-temperature environment of the reservoir layer can generate charge shielding effect and thermal motion aggravating effect on the molecular chain of the polyacrylamide thickener, and the conformation of the molecular chain is triggered to change, so that the molecular chain is shrunk and curled in the aqueous solution, and finally, the viscosity of the system is obviously reduced. Aiming at the problems, the prior art mostly introduces a 2-acrylamide-2-methylpropanesulfonic acid and a hydrophobic association structural unit into the side chain of the polyacrylamide thickener by molecular design so as to reduce the contracture degree of a molecular chain in a solution and maintain the stretching state of the molecular chain, thereby improving the salt resistance and the temperature resistance thickening performance of the thickener. However, the hydrophobic association type physical crosslinking network is sensitive to shearing action, and is easy to generate structural damage under the shearing action, so that the thickening performance of the polymer is directly reduced, and the performance advantage of the polymer under the conditions of high salt and high temperature is difficult to fully develop. The double bonds in the tung oil molecules can be polymerized with acrylamide to form a stable chemical crosslinking network, so that the movement of polymer molecule chain segments can be effectively limited, the shearing stability of the polymer network is improved, and the thickening performance of the thickener under the conditions of high salt, high temperature and dynamic shearing is improved. Disclosure of Invention The first object of the invention is to provide a tung oil-based polyacrylamide thickener, which improves the salt-resistant and temperature-resistant thickening properties of polyacrylamide. A second object of the present invention is to provide a method for preparing a tung oil based polyacrylamide thickener. A third object of the present invention is to provide the use of a tung oil based polyacrylamide thickener. The first technical scheme adopted by the invention is that the preparation method of the tung oil-based polyacrylamide thickener comprises the following steps: step one, adding a polymerization monomer into a reaction container added with water, stirring until the polymerization monomer is completely dissolved, and regulating the pH value to 6.5-7.5 to obtain a polymerization solution; Step two, adding a composite initiator into the polymerization solution, heating the polymerization solution to 40-60 ℃ to initiate free radical polymerization, introducing nitrogen with the purity of 99.99% into the polymerization solution to remove dissolved oxygen, stopping introducing nitrogen, and then sealing a reaction container for constant-temperature reaction to obtain polymer gel; and thirdly, sequentially granulating, drying, crushing and sieving the polymer gel to obtain the tung oil-based polyacrylamide thickener. The first technical scheme of the invention is characterized in that: The polymerization monomer consists of 70-80 parts of acrylamide, 5-8 parts of tung oil, 5-15 parts of 2-acrylamide-2-methylpropanesulfonic acid and 5-8 parts of tween 80 by total mass of the polymerization monomer. The total mass of the polymerized monomer and water is 20-30 parts. In the second step, the composite initiator is formed by compounding an oxidation initiator, a reduction initiator and an azo initiator, wherein the mass ratio of the oxidation initiator to the reduction initiator to the azo initiator is 1:1:1, and the addition amount of the composite initiator accounts for 0.06 part of the total mass of the polymerized monomers. The oxidation type initiator adopts potassium persulfate or ammonium persulfate, the reduction type initiator adopts sodium bisulphite or sodium ascorbate, and the azo type initiator adopts AIBN or V 50. Introducing nitrogen w