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CN-121991297-A - Temperature-resistant polycarboxylic acid dispersing agent for oil well cement and preparation method thereof

CN121991297ACN 121991297 ACN121991297 ACN 121991297ACN-121991297-A

Abstract

The invention belongs to the technical field of dispersants for oil well cement, and particularly relates to a temperature-resistant polycarboxylic acid dispersant for oil well cement and a preparation method thereof. The polycarboxylic acid dispersant has a structure represented by formula (1). The dispersing agent provided by the invention has good dispersing performance at high temperature, good compatibility with other oil well cement additives at 150 ℃, can effectively reduce the initial consistency of cement paste, does not influence other performances of cement paste and cement stone, and has the advantages of simple preparation method, low raw material cost and environment-friendly production and use processes.

Inventors

  • LIANG YUANBIN
  • ZHAO QIYANG
  • CHEN ZHICHAO
  • ZHANG ZUOHONG
  • ZENG KE
  • LIU HUAZHI
  • YAN HAIBING
  • CHE XIAOPENG
  • YANG GUOLIANG
  • ZENG PEIHUA

Assignees

  • 中国石油天然气集团有限公司
  • 中国石油集团川庆钻探工程有限公司

Dates

Publication Date
20260508
Application Date
20241105

Claims (12)

  1. 1. A temperature-resistant polycarboxylic acid dispersant for oil well cement is characterized by having a structure represented by formula (1): Wherein R 1 is hydrogen or carboxyl, and R 2 is carboxyl, or R 1 and R 2 form a ring to form anhydride; R 3 is hydrogen, C1-C6 alkyl or C1-C6 carboxyalkyl; R 4 is a phosphate group, a phosphate ester group, or an alkyl phosphate ester group; R 5 、R 6 、R 8 is each independently hydrogen or C1-C6 alkyl; R 7 is a quaternary ammonium ion, or R 6 and R 7 form a ring to form a cyclic quaternary ammonium ion; R 9 is C6-C16 aryl, C5-C16 hydrocarbon cyclic group or C5-C16 heterocyclic group; m is an integer of 1 to 6; n is an integer of 40 to 60; a. b, c, d, e is the mole number and a: b: c: d: e=0.04 to 0.4:0.01 to 0.15:0.02 to 0.25:0.04 to 0.20:0.01 to 0.15.
  2. 2. The polycarboxylic acid dispersant of claim 1, wherein R 7 is -COO(CH 2 ) p [N(CH 3 ) 3 ] + 、-(CH 2 ) p [N(CH 3 ) 3 ] + or-CON (CH 2 ) p [N(CH 3 ) 3 ] + , p is an integer of 1 to 6, or R 6 and R 7 form a ring and -(CH 2 CH 2 ) q (CH 3 )N + (CH 3 )(CH 2 CH 2 ) q -,q is an integer of 1 to 6.
  3. 3. The polycarboxylic acid dispersant of claim 1, wherein R 9 is phenyl or pyrrolidone.
  4. 4. The polycarboxylic acid dispersant of claim 1, wherein the weight average molecular weight of the polycarboxylic acid dispersant is 10000-80000.
  5. 5. A method for preparing a polycarboxylic acid dispersant as set forth in any one of claims 1 to 4, wherein the method comprises the steps of: in the absence of oxygen, in the presence of an initiator and a chain transfer agent, enabling a monomer I with a structural unit shown in a formula (I), a monomer II with a structural unit shown in a formula (II), a monomer III with a structural unit shown in a formula (III), a monomer IV with a structural unit shown in a formula (IV), a monomer V with a structural unit shown in a formula (V) and water to contact for free radical copolymerization; Wherein ,R 1 、R 2 、R 3 、R 4 、R 5 、R 6 、R 7 、R 8 、R 9 、m、n is as defined in claim 1; The mass ratio of the monomer I to the monomer II to the monomer III to the monomer IV to the monomer V is 0.5-3:0.05-1.5:0.5-3.5:10-50:0.05-1.5.
  6. 6. The preparation method of claim 5, wherein the mass ratio of the monomer III to the monomer I is 1:3-3:1.
  7. 7. The method according to claim 5, wherein the monomer II is at least one selected from the group consisting of vinyl phosphoric acid, 2- (methacryloyloxy) ethyl phosphate and vinyl phosphate.
  8. 8. The method according to claim 5, wherein the monomer III is at least one selected from the group consisting of methacryloyloxyethyl trimethyl ammonium chloride, dimethyl diallyl ammonium chloride, methacrylamidopropyl trimethyl ammonium chloride and allyl trimethyl ammonium chloride.
  9. 9. The method according to claim 5, wherein the monomer V is at least one selected from the group consisting of N-vinyl-2-pyrrolidone and styrene.
  10. 10. The process according to claim 5, wherein the monomer I is at least one selected from the group consisting of acrylic acid, methacrylic acid, maleic acid and maleic anhydride, and/or the monomer IV is at least one selected from the group consisting of isopentenol polyoxyethylene ether and methallyl alcohol polyoxyethylene ether.
  11. 11. The method according to claim 5, wherein the initiator is at least one selected from the group consisting of ammonium persulfate, sodium persulfate and potassium persulfate, and/or the chain transfer agent is at least one selected from the group consisting of sodium methallyl sulfonate, sodium hypophosphite, thioglycollic acid, 3-mercaptopropionic acid and mercaptoethanol.
  12. 12. The preparation method according to claim 5, wherein the reaction temperature is 50-80 ℃ and the reaction time is 0.5-2 h.

Description

Temperature-resistant polycarboxylic acid dispersing agent for oil well cement and preparation method thereof Technical Field The invention belongs to the technical field of dispersants for oil well cement, and particularly relates to a temperature-resistant polycarboxylic acid dispersant for oil well cement and a preparation method thereof. Background In the oil-gas well cementation engineering, cement slurry needs to flow through the hollow of the casing and then return from the bottom of the well to a narrow annular space between the casing and the well wall, which requires good performance of the cement slurry. It is generally necessary to adjust the properties of cement slurries by adding various additives to the cement to meet the construction requirements. The dispersant is used as one of three additives of oil well cement, can reduce the flow resistance of cement slurry, maintain the fluidity of cement slurry, enable the cement slurry to reach turbulent flow at a lower pumping speed, is beneficial to improving the well cementation quality, and plays a vital role in well cementation operation. In recent years, oil and gas exploration and development gradually expands to high-temperature high-pressure complex environments, and the rheological property of cement paste is seriously affected by deep high-temperature environments, so that development of high-performance dispersing agents is urgently needed to meet the exploitation requirements of deep wells, ultra-deep wells and complex wells. At present, the sulfonated aldehyde ketone polycondensate dispersant is an oil well cement dispersant which is used in a large amount at home and abroad. The high-temperature-resistant high-strength cement paste is adsorbed on cement particles through electrostatic action so as to generate electrostatic repulsive force to prevent flocculation, has good performance in a high-temperature cement paste body, and has the advantages of low price, simplicity in preparation and good compatibility with a plurality of additives. However, with the continuous emergence of various novel materials and the increasing of environmental protection requirement standards, such dispersants also have problems of low dispersing efficiency and environmental pollution. In order to solve the problems, the polycarboxylic acid dispersant has the advantages of strong designability of molecular structure, excellent dispersion performance, environmental friendliness and the like, and is a development direction and research hot spot of high-performance cement dispersants in recent years. Polycarboxylic acid is used as a new generation of dispersing agent and is widely applied to the construction industry, the dispersing agent is a comb-shaped polymer, generally consists of a main chain of polycarboxylic acid and a polyether side chain, and realizes the dispersing effect on cement particles through electrostatic repulsion and steric hindrance effect. However, the high-temperature-resistant cement cannot be directly and universally applied to the oil well cement industry due to the problems of poor temperature resistance, poor compatibility and strong retarder. Aiming at the defect of insufficient application research of the polycarboxylic acid dispersing agent in high-temperature oil well cement, the polycarboxylic acid dispersing agent has limited effect of improving the temperature resistance of the existing polycarboxylic acid dispersing agent, and still cannot meet the requirement of high-temperature well cementation. Therefore, in order to meet the actual production demands of more and more high-temperature deep wells, it is highly needed to develop a polycarboxylic acid dispersing agent with high temperature resistance, weak retarder and strong compatibility. Disclosure of Invention The invention aims to provide a temperature-resistant polycarboxylic acid dispersing agent for oil well cement and a preparation method thereof, aiming at the problems of insufficient temperature resistance, poor compatibility, strong retarder and the like of the traditional polycarboxylic acid dispersing agent. The prepared dispersing agent has good dispersing performance at high temperature by introducing the phosphoric acid anchoring group, the rigid group and the cationic group, has good compatibility with other oil well cement additives at 150 ℃, can effectively reduce the initial consistency of cement paste, does not influence other performances of cement paste and set cement, has simple preparation method, low raw material cost and environment-friendly production and use process, and greatly solves the problems of poor temperature resistance, strong retarder and poor compatibility of the polycarboxylic acid dispersing agent. In a first aspect of the present invention, there is provided a temperature-resistant polycarboxylic acid dispersant for oil well cement, having a structure represented by formula (1): Wherein R 1 is hydrogen or carboxyl, and R 2 is car