海水水泥浆体系降失水剂LTF-100L的合成及性能

Synthesis and properties of LTF-100L fluid loss additive available in seawater-based cement slurry system

以2-丙烯酰胺基-2-甲基丙磺酸、N，N-二甲基丙烯酰胺、不饱和双羧基单体和不饱和阳离子单体二甲基二烯丙基氯化铵为原料合成了一种新型降失水剂（LTF-100L）。利用FTIR、GPC、流变测试和稠化实验等分析了LTF-100L的结构，考察了它在海水水泥浆中的性能。表征结果显示，LTF-100L为目标产物，Mw=413×10^5，Mn=3．5×10^5，Mw／Mn=1．25。存海水水泥浆体系中，当LTF-100L用量为3％（w）（基于水泥浆质量）时，水泥浆流性指数为0．909，稠度系数仅为0．153。LTF-100L能改善海水配浆过程中易触变和易增稠的问题，避免水泥浆体系存低温稠化实验中出现“鼓包”和“包芯”的现象，具有良好的“停开机”稠度稳定性。含LTF-100L的水泥浆早期强度发展较快，能满足固井施工要求。

A new fluid loss additive（LTF-100L） was synthesized from 2-acrylamido-2-methylpropane sulfonic acid, N, N-dimethyl acrylamide, unsaturated dicarboxylic acid and unsaturated cationic monomer dimethyl diallyl ammonium chloride. Its structure and performances in seawaterbased cement slurry were investigated by means of FTIR, GPC, rheology test and thickening experiments. The results showed that LTF-100L was the target product with Mw of 4.3 × 105, M, of 3.5 ×105 and Mw/Mn of 1.25. When the LTF-100L content was at 3%（w）（based on the mass of the cement slurry）, the rheological behavior index of the cement slurry reached 0.909 and the consistency coefficient was 0.153 only. The phenomena like thixotropy and thickening in the preparation of the sea-water cement slurry can be improved by adding LTF-100L to avoid undesirable ＂false set＂ or ＂abnormal gel＂ in the thickening experiments, and the sea-water cement slurry exhibited a good stopping-starting up stability. The early strength of the cement slurry containing LTF-100L developed rapidly, which could meet the requirement of cementing operation.