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硅酸盐通报 ›› 2023, Vol. 42 ›› Issue (3): 802-807.

所属专题: 水泥混凝土

• 水泥混凝土 • 上一篇    下一篇

早期水热养护对铝酸钙水泥结构稳定性的影响

周剑峰1, 杨涛2, 张菁燕1, 周文平1, 高璇2   

  1. 1.常州市建筑科学研究院集团股份有限公司,常州 213000;
    2.盐城工学院材料科学与工程学院,盐城 224051
  • 收稿日期:2022-10-18 修订日期:2022-12-08 出版日期:2023-03-15 发布日期:2023-03-31
  • 通信作者: 杨 涛,博士,副教授。E-mail:taoyang1121@ycit.edu.cn
  • 作者简介:周剑峰(1974—),男。主要从事建筑材料研发、工程事故分析等方面的研究。E-mail:1093802847@qq.com
  • 基金资助:
    国家自然科学基金青年基金(51702278);江苏省“青蓝工程”优秀青年骨干教师

Effect of Early-Age Hydrothermal Curing on Structural Stability of Calcium Aluminate Cement

ZHOU Jianfeng1, YANG Tao2, ZHANG Jingyan1, ZHOU Wenping1, GAO Xuan2   

  1. 1. Changzhou Architectural Research Institute Group Co., Ltd., Changzhou 213000, China;
    2. School of Materials Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, China
  • Received:2022-10-18 Revised:2022-12-08 Online:2023-03-15 Published:2023-03-31

摘要: 稠油热采常使用具有早强和耐高温特性的铝酸钙特种水泥完成固井作业,为保证固井安全和采油效率,需明确早期水热养护对水泥硬化体结构稳定性的影响。本文研究了20、50、80 ℃下水泥的强度发展、矿物相组成和微观结构。结果表明,水热养护过程中铝酸钙水泥中的钙铝黄长石、CAH10和C2AH8等主要矿物相逐步转变为胶结性差的颗粒状水榴石,导致硬化体结构疏松多孔,进而引发硬化体抗压强度衰退。掺入粉煤灰和矿渣无法有效抑制晶型转变和结构破坏,但六偏磷酸钠改性可使矿物相保持结构稳定性,六偏磷酸钠溶出的Na+、HPO-4与铝酸钙水泥溶出的Ca2+、[AlO4]5-反应生成水化磷铝酸钠钙(N-C-A-P-H)凝胶相产物,进一步提高了硬化体的致密度和胶结特性。

关键词: 铝酸钙水泥, 固井, 稠油热采, 矿相转变, 微观结构, 稳定性

Abstract: Calcium aluminate special cement with rapid early-age strength development and high-temperature resistance is frequently utilized for well cementing operations in heavy oil thermal recovery. It is essential for understanding the effect of early-age hydrothermal curing on the structural stability of cement binder to maintain cementing safety and oil recovery effectiveness. The strength development, mineral composition, and microstructure of cement cured at 20, 50 and 80 ℃ were investigated. The results show that the main mineral phases formed in calcium aluminate cement, such as gehlenite, CAH10 and C2AH8, gradually transform into granular hydrogarnet with poor cementation during hydrothermal curing, resulting in loose and porous structure of cement binder, which leads to the decline in compressive strength. The incorporation fly ash and slag can not effectively prevent the crystal transformation and structural damage. The modification of sodium hexametaphosphate maintains the structural stability of mineral phases, and the dissolved Na+ and HPO-4 ions released from hexametaphosphate react with Ca2+ and [AlO4]5- ions released from cement to generate sodium calcium aluminophosphate hydrate (N-C-A-P-H) gel phase products, which further enhances the density and cementation performance of cement binder.

Key words: calcium aluminate cement, well cementing, heavy oil thermal recovery, mineral transformation, microstructure, stability

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