ZHAO Kunpeng¹, WANG Tao², GUO Chun², LUO Yangli³, WEI Tingcong¹, MEI Kaiyuan¹,ZHANG Chunmei¹, ZHAO Feng¹, CHENG Xiaowei¹

(1.School of New Energy and Materials, Southwest Petroleum University, Chengdu 610000, China;2.Sichuan Huashuntong Energy Technology Development Co., Ltd., Chengdu 610000, China;3.Sichuan Chuanqing Underground Technology Co., Ltd., Guanghan 618300, China)

Abstract：In order to restrain the strength decline of cement stone at high temperature, the influence of the addition of silica fume and the synergistic effect of red mud and silica fume at high temperature on the compressive strength of G-grade oil well cement stone were studied, and the changes of cement hydration products at high temperature were analyzed by means of X-ray diffraction and thermogravimetry.The microstructure of cement stone was observed by scanning electron microscope.The results show that after curing at 225 ℃ for 7 d, 35% silica fume(mass fraction)can improve the high temperature mechanical properties of the cement stone, and 5% red mud(mass fraction)can help the silica fume to further improve the strength of cement stone at high temperature.Comparing with the control group, its compressive strength is improved by 11.3%.The addition of red mud promotes the formation of fibrous xonotlite(C₆S₆H)phase in cement stone.The internal pore structure of the cement stone is reduced, and the internal structure of cement stone is dense.

Keywords：red mud；silica fume；G-grade oil well cement；strength declination；high temperature curing

Received：2022-08-29，Revised：2022-10-14,Online：2023-01-31 15:38。

Funding Project：四川省区域创新合作项目，编号：2021YFQ0045。

First Author：赵昆鹏(1998—)，男，硕士研究生，研究方向为固井水泥石高温力学性能。E-mail：zkp10010@163.com。

Corresponding Author：程小伟(1977—)，男，教授，博士，博士生导师，研究方向为先进胶凝材料与其在固井中应用。E-mail：chengxw@swpu.edu.cn。