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CN-122010447-A - Mullite whisker modified toughening agent, preparation method thereof and well cementation cement paste comprising mullite whisker modified toughening agent

CN122010447ACN 122010447 ACN122010447 ACN 122010447ACN-122010447-A

Abstract

The invention discloses a mullite whisker modified toughening agent, a preparation method thereof and well cementation cement slurry comprising the mullite whisker modified toughening agent, and belongs to the technical field of oil and gas field development well cementation materials. The mullite whisker modified toughening agent provided by the invention has good application effect in well cementing cement paste, the grain size of the toughening agent is similar to that of oil well cement grains, and when a cement stone forms micro cracks, the mechanical properties of the cement stone can be improved by utilizing the advantages of the toughening agent such as smaller size, special three-dimensional needle-like structure and the like and through the reinforcing effects of crack bridging, deflection, whisker extraction and the like.

Inventors

  • ZHENG YOUZHI
  • LI WENZHE
  • ZHAO JUN
  • JIAO LIBIN
  • ZHANG ZHANWU
  • HE LANG

Assignees

  • 中国石油天然气股份有限公司

Dates

Publication Date
20260512
Application Date
20241112

Claims (10)

  1. 1. The mullite whisker modified toughening agent is characterized by comprising, by weight, 10-20 parts of mullite whisker, 0.05-0.4 part of surfactant and 3-18 parts of nano silicon dioxide.
  2. 2. The mullite whisker modified toughener of claim 1, wherein the surfactant is selected from one or more of cetyltrimethylammonium bromide, polyacrylamide, triethanolamine, or polymethylpyrrolidone.
  3. 3. The mullite whisker modified toughener of claim 2, wherein the mullite whisker is prepared from the following raw materials, by weight, 20-30 parts of amorphous SiO 2 , 20-30 parts of Al 2 (SO 4 ) 3 and 50-100 parts of Na 2 SO 4 .
  4. 4. The mullite whisker modified toughener of claim 3, wherein the mullite whisker has a whisker length of 1-5 μm and an aspect ratio of 12-30.
  5. 5. A method of preparing the mullite whisker modified toughener of any one of claims 1 to 4, comprising the steps of: s1, dispersing mullite whiskers in deionized water to obtain mullite whisker suspension; s2, stirring and mixing the mullite whisker suspension and a surfactant to obtain a first mixed solution; S3, adding the first mixed solution into a nano silicon dioxide solution, regulating a reaction system to be alkalescent by using an acid solution, and simultaneously heating the reaction system for reaction to obtain a reaction product; And S4, washing, filtering and drying the reaction product in sequence to obtain the mullite whisker modified toughening agent.
  6. 6. The preparation method of the mullite whisker modified toughener according to claim 5, wherein in the step S1, the mass fraction of mullite whisker in the mullite whisker suspension is 10-20%.
  7. 7. The method for preparing a mullite whisker modified toughener according to claim 5, wherein in the step S3, the heating reaction is performed at a temperature of 50-70 ℃ for 1-3 hours.
  8. 8. The method for preparing the mullite whisker modified toughener according to any one of claims 5 to 7, wherein the mullite whisker is prepared by the following method: Mixing and grinding amorphous SiO 2 、Al 2 (SO 4 ) 3 and Na 2 SO 4 to obtain a grinding mixture; heating the grinding mixture to 900-1200 ℃, preserving heat for 2-4 hours, and cooling to room temperature along with a furnace to obtain a calcined product; and cleaning, drying and grinding the calcined product in sequence to obtain the mullite whisker.
  9. 9. A well cementing slurry comprising oil well cement, silica fume, a suspending agent, a fluid loss agent, a dispersing agent, a retarder, and the mullite whisker modified toughener of any one of claims 1 to 4.
  10. 10. The well cementing slurry according to claim 9, wherein the mullite whisker modified toughener is 0.5-2% by mass based on 100% by mass of the oil well cement.

Description

Mullite whisker modified toughening agent, preparation method thereof and well cementation cement paste comprising mullite whisker modified toughening agent Technical Field The invention belongs to the technical field of oil and gas field development well cementation materials, and particularly relates to a mullite whisker modified toughening agent, a preparation method thereof and well cementation cement paste comprising the same. Background The well cementation operation of the oil and gas well is to inject cement paste into an annulus between a well wall and a sleeve, and cement paste is formed after setting and hardening, so that the functions of interval packing, supporting and protecting the sleeve are realized. At present, the development field of oil and gas wells gradually develops to deep and ultra-deep layers, so that the difficulty and challenges of lower cement stone strength, faster cement stone strength decay and the like in a high-temperature and high-pressure environment are inevitably faced to a well cementation project. In the development process of the oil and gas well, a certain load effect can be generated underground, the cement is applied to the cement sheath through the sleeve, particularly, the large hydraulic fracturing of the shale gas well, the periodic strong injection and production of the gas storage and the like are performed on the cement sheath, so that the cement sheath performance is deteriorated, the cement sheath is easy to crack to form cracks to cause the failure of the integrity of the cement sheath, the blocking effect on underground oil, gas and water layers is lost, the interlayer channeling is caused, the sleeve is corroded, and even the oil and gas well is scrapped. At present, the conventional oil well cement toughening agent is faced with a plurality of problems of low compressive strength, rapid strength decay and the like of cement stones at high temperature in ultra-deep well cementation, so that the development of the toughening agent suitable for toughening the high-temperature-resistant cement stones is particularly important based on the high-temperature operation working condition that the underground temperature is higher than 240 ℃. The conventional common toughening additive for the oil well cement stone comprises rubber particles, fibers, graphite, latex and the like, and is mainly used for improving the mechanical property and durability of the oil well cement stone so as to prolong the service life of the cement stone. However, the toughening agents commonly used at present have certain limitations, such as poor compatibility of rubber particles and cement paste, easy agglomeration of fiber materials in the cement paste, easy pipe blockage and the like, poor dispersibility of graphite materials in the cement paste, insufficient temperature resistance of latex materials and large dosage. In the prior art, as disclosed in the patent publication No. CN114525119A, the name of the invention is a preparation method of an inorganic fiber toughening agent for oil-gas well cementing slurry, the proposal discloses that basalt fibers, carbon fibers, brucite fibers and silicon carbide fibers are pretreated, then mixed, and then subjected to surface roughening and surface modification process treatment to obtain the inorganic fiber toughening agent. In another embodiment, the invention patent with publication number CN113402186a, entitled "preparation method of cement paste toughening agent, cement paste and preparation method thereof" is disclosed, wherein the patent respectively carries out surface modification treatment on carbon fiber and nano-particles, then the surface modified nano-particles and the surface modified carbon fiber react by controlling temperature and time, and the cement paste toughening agent is obtained by combining in a chemical bonding manner. Although the toughness of the cement sheath can be improved in the prior art, the problems of poor rheological property, strength attenuation and the like of cement slurry still exist in a high-temperature environment higher than 240 ℃. Therefore, it is important to develop a toughening agent which has no influence on the application performance of the high-temperature well cementation cement paste and can enhance the cement sheath. Disclosure of Invention In order to solve the problems of the prior art, the main purpose of the invention is to provide a mullite whisker modified toughening agent, a preparation method thereof and a well cementation cement slurry comprising the mullite whisker modified toughening agent, wherein the mullite whisker modified toughening agent has good dispersibility in aqueous solution, stable performance, strong toughening performance and high temperature resistance, and meanwhile, the well cementation cement slurry prepared by adopting the mullite whisker modified toughening agent has good stability, no sedimentation phenomenon and adjustable thickening time, and