碳纳米管羧基功能化及其对水泥石的影响

Carboxyl Functionalized Carbon Nanotube and Its Effects on Set Cement

随着非常规油气井开发的不断深入,复杂的地下环境对水泥石的各项力学性能指标提出更高的要求,因此,急需开发高性能的纳米材料用于改造水泥石性能。采用稀酸酸化工艺制备羧基功能化碳纳米管分散液,通过接触角、紫外-可见吸收光谱和沉降稳定性等测试对分散液的分散能力进行讨论,并对羧基功能化碳纳米管提高水泥石力学性能的效果进行了验证。研究结果表明,羧基功能化可使碳纳米管的粒径减小89.71%,并使疏水材料转变为亲水材料,同时,羧基功能化碳纳米管在水中的分散稳定性提升100%;0.005%加量的羧基功能化碳纳米管使水泥石的抗压强度提高16.05%,抗折强度提高25.82%,抗拉强度提高18.07%。

With the continual development of unconventional oil and gas,complex downhole conditions have presented higher requirements on the various mechanical properties of set cement for well integrity,and these requirements have urged the development of high performance nanomaterials for improving the performance of the set cement.In this study,a carboxyl functionalized carbon nanotube dispersion was developed through dilute-acid acidization process.The dispersibility of the dispersion was measured by means of contact-angle measurement,UV-visible absorption spectroscopy as well as settling stability measurement etc.,and the effect of the carboxyl functionalized carbon nanotube on improving the mechanical properties of set cement was verified.The study shows that carboxyl functionalization reduces the diameters of the carbon nanotube particles by 89.71%,and can convert a hydrophobic material to hydrophilic one.Carboxyl functionalization also improves the dispersion stability of the carbon nanotube by 100%.A cement slurry treated with 0.005%carboxyl functionalized carbon nanotube has the compressive strength of the set cement increased by 16.05%,the flexural strength by 25.82%,and the tensile strength by 18.07%.