固井水泥环微裂纹自修复微胶囊的制备与性能研究

Synthesis and Performance Study of Self-repairing Microcapsules for Micro-cracks of Oil-well Cement Matrix

采用原位聚合法合成了一种新型油井水泥石微裂纹自修复微胶囊(以环氧树脂为囊芯、脲醛树脂为囊壁)。并使用激光粒度仪、扫描电子显微镜(SEM)、红外光谱仪(FT-IR)和差热-热重分析仪(TG/DTA)等方法分别对微胶囊的粒径分布、表面形貌、化学构成和热稳定性等进行了研究。将微胶囊加入水泥浆体后,通过测试油井水泥石损伤前后的抗压强度值和强度回复率评价了微胶囊的自修复效果。研究结果表明:实验所制备微胶囊的平均粒径约为36.08μm,表面较为粗糙,具有良好的热稳定性。此外,微胶囊的加入在提高水泥石(回复后)抗压强度值的同时,能将水泥石的抗压强度回复率η提高2~3倍,且微胶囊的加量为1.5wt%时,水泥石试样具有最优异的力学性能。

A new type of self-repairing microcapsules（with epoxy resin as the core and urea formaldehyde resin as the wall） for micro-cracks of oil-well cement matrix. The particle size distribution,surface topography,chemical composition and thermal stability of the microcapsules were analyzed by the Laser particle size analyzer, scanning electron microscopy（SEM）, infrared spectroscopy（FT-IR） and differential thermal gravimetric analyzer（TG/DTA） respectively. After preparation,microcapsules were added into cement paste,and the compressive strength and strength recovery rate of oil-well cement matrix were tested to evaluate the self-repairing effect of microcapsule. The results show that the average particle size is about 36. 08 μm,the surface of microcapsules is rough and its thermal stability is good. In addition,the addition of microcapsules can improve the compressive strength of cement matrix by increasing the strength recovery rate η of cement matrix（after repairing） to 2-3 times co MPared to that of pure cement matrix. When the content of microcapsule is 1. 5 wt%,the samples have the most excellent mechanical properties than the others.