Thickening progression mechanism of silica fume-oil well cement composite system at high temperatures  

作　　者：Hang Zhang Miao-Miao Hu Peng-Peng Li Guo-Qing Liu Qing-Lu Chang Jie Cao Ming Liu Wen-Hua Xu Xiu-Jian Xia Jin-Tang Guo 

机构地区：[1]School of Chemical Engineering and Technology,Tianjin University,Tianjin,300350,China [2]Zhejiang Institute of Tianjin University,Shaoxing,312300,Zhejiang,China [3]Haihe Laboratory of Sustainable Chemical Transformations,Tianjin,300192,China [4]CNPC Engineering Technology R&D Company Limited,Beijing,102206,China

出　　处：《Petroleum Science》2024年第4期2793-2805,共13页石油科学（英文版）

基　　金：supported by the Basic Research and Strategic Reserve Technology Research Fund Project of China National Petroleum Corporation (Grant No.2021DQ03-14);the National Natu ral Science Foundation of China (Grant No.52204010);Haihe Laboratory of Sustainable Chemical Transformations for financial support。

摘　　要：This work studied the thickening progression mechanism of the silica fume-oil well cement composite system at high temperatures(110-180.C)in order to provide a theoretical guidance for the rational application of silica fume in the cementing engineering.Results showed that silica fume seldom affected the thickening progression of oil well cement slurry at 110-120.C,but when temperature reached above130.C,it would aggravate the bulging degree of thickening curves and significantly extend the thickening time,meanwhile causing the abnormal“temperature-based thickening time reversal”and“dosage-based thickening time reversal”phenomena in the range of 130-160.C and 170-180.C respectively.At 130-160.C,the thickening time of oil well cement slurry was mainly associated with the generation rate of calcium hydroxide(CH)crystal.The introduced silica fume would be attracted to the cement minerals'surface that were hydrating to produce CH and agglomerate together to form an“adsorptive barrier”to hinder further hydration of the inner cement minerals.This“adsorptive barrier”effect strengthened with the rising temperature which extended the thickening time and caused the occurrence of the“temperature-based thickening time reversal”phenomenon.At 170-180.C,the pozzolanic activity of silica fume significantly enhanced and considerable amount of C-S-H was generated,thus the“temperature-based thickening time reversal”vanished and the“dosage-based thickening time reversal”was presented.

关 键 词：Silica fume Oil well cement Thickening time reversal Pozzolanic reaction Adsorptive barrier CH and C-S-H 

分 类 号：TE256[石油与天然气工程—油气井工程]