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CN-122012059-A - Wax inhibitor for deep water low-temperature high-pressure environment and preparation method thereof

CN122012059ACN 122012059 ACN122012059 ACN 122012059ACN-122012059-A

Abstract

The invention discloses a wax-proofing agent for a deep water low-temperature high-pressure environment and a preparation method thereof, wherein the wax-proofing agent consists of a main wax-proofing agent, a salt-resistant compound surfactant, a low-temperature compatible solvent, a corrosion inhibition synergistic agent and a stabilizer; the preparation method is that the components form a stable homogeneous system through a sectional temperature-control shearing dispersion process. The wax inhibitor has excellent temperature resistance, compression resistance, salt resistance stability and high-efficiency wax crystal regulation and control capability under the conditions of 0-15 ℃ and 5-150 MPa and formation water mineralization of 2000-50000 mg/L, has good metal corrosion inhibition and nonmetallic material compatibility, and simultaneously has high industrialization feasibility and controllable cost, effectively solves the problem of wax deposition in the deep water oil and gas field exploitation process, and has important significance for improving the economy and safety of deep water oil and gas field development.

Inventors

  • WANG XIANG
  • SONG XIAOLI
  • LI DONGNING
  • WANG ZHIYUAN
  • LIU JUNJUN
  • ZHANG GUOXIN
  • LU YUAN
  • HU TING
  • ZHANG MIAOWEI
  • DAI JUNFENG
  • WANG JING
  • LIU ZHIGUANG

Assignees

  • 中海油(天津)油田化工有限公司

Dates

Publication Date
20260512
Application Date
20260320

Claims (10)

  1. 1. The wax-proofing agent for the deep water low-temperature high-pressure environment is characterized by comprising the following components in percentage by mass: 15% -30% of a main wax inhibitor; 5% -15% of salt-tolerant compound surfactant; 42% -60% of a low-temperature compatible solvent; 3% -8% of corrosion inhibition synergist; 2% -5% of stabilizer.
  2. 2. The wax-proofing agent for deep water low-temperature high-pressure environment according to claim 1, wherein the main wax-proofing agent is a long-chain alkyl acrylate-maleic anhydride-styrene derivative ternary block copolymer, the long-chain alkyl carbon number of the long-chain alkyl acrylate is C16-C22, the molar ratio of the long-chain alkyl acrylate to the maleic anhydride to the styrene derivative is 2:1 (0.3-0.8), the weight average molecular weight M w of the block copolymer is 5000-15000, the long-chain alkyl acrylate is hexadecyl methacrylate or octadecyl methacrylate, and the styrene derivative is at least one of alpha-methyl styrene, p-methyl styrene or p-tert-butyl styrene.
  3. 3. The method for preparing the main paraffin inhibitor for the deep water low-temperature high-pressure environment according to claim 2, which is characterized by comprising the following steps: s1, adding long-chain alkyl acrylate, maleic anhydride and a styrene derivative into a reaction kettle, adding a polymerization solvent, and stirring until the mixture is uniformly dispersed; s2, after removing oxygen in the reaction kettle, heating to 80-90 ℃, adding an initiator, and carrying out constant-temperature polymerization for 4-10 hours under the stirring condition; S3, after the polymerization reaction is finished, cooling the reaction system, washing with absolute ethyl alcohol, standing for precipitation, and removing a liquid phase to obtain a solid-phase product; S4, vacuum drying the solid phase product to obtain the white powdery ternary block copolymer main wax inhibitor.
  4. 4. The wax-proofing agent for deep water low-temperature high-pressure environment according to claim 3, wherein the polymerization solvent is dimethylbenzene, and the dosage of the polymerization solvent is 1.5-2.0 times of the total mass of long-chain alkyl acrylate, maleic anhydride and styrene derivative monomers; The initiator is benzoyl peroxide or azodiisobutyronitrile, and the amount of the initiator is 0.3-1.5% of the total mass of the long-chain alkyl acrylate, maleic anhydride and styrene derivative monomers.
  5. 5. The wax-proofing agent for the deep water low-temperature high-pressure environment according to claim 1, wherein the salt-resistant compound surfactant is formed by compounding polyoxyethylene alkylamine and sodium dodecyl benzene sulfonate according to a mass ratio of (1-3) 1, wherein the polyoxyethylene polymerization degree of the polyoxyethylene alkylamine is 20-30, and the polyoxyethylene alkylamine is at least one of dodecylamine polyoxyethylene ether, stearylamine polyoxyethylene ether or cocoamine polyoxyethylene ether.
  6. 6. The wax-proofing agent for the deepwater low-temperature high-pressure environment according to claim 1 is characterized in that the low-temperature compatible solvent is formed by mixing propylene glycol methyl ether and N-methylpyrrolidone according to a volume ratio of 1 (2-1), the corrosion inhibition synergist is a sulfur-containing oxazoline derivative, and the sulfur-containing oxazoline derivative is 2-mercaptothiazoline or 2-methyl-4-isothiazolin-3-ketone.
  7. 7. The wax-proofing agent for deep water low-temperature high-pressure environment according to claim 1, wherein the stabilizer is sorbitan monooleate.
  8. 8. A method for preparing the wax inhibitor for the deep water low-temperature high-pressure environment according to one of claims 1 to 7 is characterized by comprising the following steps: s1, adding a low-temperature compatible solvent into a reaction kettle, heating to a dispersing temperature, adding a salt-resistant compound surfactant, and stirring until the salt-resistant compound surfactant is completely dissolved; S2, adding a main wax inhibitor into the reaction kettle, heating to a shearing temperature, and shearing and dispersing under vacuum to form uniform colloid; And S3, cooling the colloid reacted in the step S2 to a mixed temperature, sequentially adding a corrosion inhibition synergist and a stabilizer, and stirring to obtain the wax inhibitor for the deep water low-temperature high-pressure environment.
  9. 9. The preparation method of the wax inhibitor for the deep water low-temperature high-pressure environment is characterized in that the dispersion temperature of the step S1 is 40-50 ℃, the stirring speed is 200-300 rpm, the stirring time is 20-30 min, the shearing temperature of the step S2 is 60-70 ℃, the stirring speed is 500-800 rpm, the stirring time is 30-60 min, the vacuum degree is-0.05-0.08 MPa, the mixing temperature of the step S3 is 30-40 ℃, the stirring speed is 100-200 rpm, and the stirring time is 15-25 min.
  10. 10. The application of the wax inhibitor for the deepwater low-temperature high-pressure environment in deepwater oil-gas field wax deposition control is characterized in that the application environment is a high-salt high-pressure low-temperature working condition with the temperature of 2-15 ℃, the pressure of 5-150 MPa and the formation water mineralization of 2000-50000 mg/L.

Description

Wax inhibitor for deep water low-temperature high-pressure environment and preparation method thereof Technical Field The invention belongs to the technical field of oil and gas field chemical engineering, and particularly relates to a wax inhibitor for a deep water low-temperature high-pressure environment and a preparation method thereof. Background The deepwater oil-gas field is usually located in a region of 500-1500 m on the sea floor, the environment of the deepwater oil-gas field has obvious characteristic of three high and one low, namely, the temperature of the sea floor is kept at 2-15 ℃ throughout the year, the stratum pressure can reach 10-150 MPa, the mineralization degree of stratum water is as high as 2000-50000 mg/L, and the wax content of crude oil is generally higher (15-30%). Under the extreme condition, paraffin wax (the main component is C16-C35 normal alkane) in crude oil is easy to separate out wax crystals due to temperature drop and pressure fluctuation, and wax deposition is formed. Wax deposition not only causes the effective sectional area of the pipeline to be reduced and the flow resistance to be increased, but also accelerates the corrosion of metal equipment, even causes pipeline blockage and safety accidents, and seriously influences the oil and gas exploitation efficiency and the production safety. At present, the deep water wax-proofing technology mainly depends on an umbilical cable filling chemical wax-proofing agent, the diameter of an umbilical cable filling pipe is generally 0.6-1.2 cm and is tens or hundreds of kilometers long, the application temperature is reduced from about 50 ℃ to about 2 ℃ of the seabed temperature, then an oil gas pipeline is increased to 100-200 ℃, contact materials comprise more than 10 metal and nonmetal materials such as stainless steel, perfluorinated rubber, polyether-ether-ketone, polytetrafluoroethylene and the like, the retention time in a pipe column is as long as several days to tens of days, the conveying pressure is high (more than 2 MPa), the filling point has abrupt temperature and pressure change, and the deep water wax-proofing technology has various requirements on the environmental adaptability, chemical stability, product cleanliness, viscosity, material compatibility and other performances of the umbilical cable filling wax-proofing agent. In the prior art, the main agent molecular structure of the deep water wax-proofing agent has the inherent defects that the main chain has insufficient rigidity, molecular chains are easy to be contracted under high pressure, so that wax crystal action sites are not exposed enough, and the main agent molecular structure of the deep water wax-proofing agent has no functional unit for resisting extreme environment, is easy to be subjected to structural degradation or agglomeration under high-salt and wide-range temperature change conditions, so that the wax-proofing efficiency is remarkably attenuated. The existing deepwater wax-proofing agent has insufficient adaptability under extreme working conditions, is difficult to adapt to deepwater complex conditions and long working period requirements, has weak universality, and has unbalanced environmental protection safety and economy. Therefore, the development of the deepwater wax-proofing agent with strong extreme environmental tolerance, high-efficiency wax-proofing performance and environmental protection, economy and safety has important significance in guaranteeing the flow safety of deepwater crude oil and promoting the technical development of the deepwater wax-proofing agent. Disclosure of Invention The invention provides a wax inhibitor for a deep water low-temperature high-pressure environment and a preparation method thereof, and aims to solve the problems in the prior art. The invention is realized by the following technical scheme: The wax-proofing agent for the deepwater low-temperature high-pressure environment comprises the following components in percentage by mass: 15% -30% of a main wax inhibitor; 5% -15% of salt-tolerant compound surfactant; 42% -60% of a low-temperature compatible solvent; 3% -8% of corrosion inhibition synergist; 2% -5% of stabilizer. In the technical scheme, the main wax-proofing agent is a long-chain alkyl acrylate-maleic anhydride-styrene derivative ternary segmented copolymer, the long-chain alkyl carbon number of the long-chain alkyl acrylate is C16-C22, the molar ratio of the long-chain alkyl acrylate to the maleic anhydride to the styrene derivative is 2:1 (0.3-0.8), the weight average molecular weight M w of the segmented copolymer is 5000-15000, the long-chain alkyl acrylate is hexadecyl methacrylate or octadecyl methacrylate, and the styrene derivative is at least one of alpha-methylstyrene, p-methylstyrene or p-tert-butylstyrene. In the technical scheme, the preparation method of the main wax inhibitor (long-chain alkyl acrylate-maleic anhydride-styrene derivative ternary block copolymer) comp