| 内容提要: |
Cementing security is endangered by the abnormal gelation phenomenon of cement slurry incorporating polycarboxylic additives occurred around 120 oC. The differences between gelatinous and non-gelatinous sections were investigated through various techniques. The reason of abnormal gelation phenomenon is the polycarboxylic additives combine with Ca2+, SiO42- and aluminate hydrate by cross-linking reaction. The cross-linking structure developed flocs which was embedded in calcium silicate hydrate (C-S-H) gel and intertwined around stirring shaft. The practicable methods were proposed to relieve or solve the abnormal phenomenon of cement slurry. |