Wang Yanling, Jiang Baoyang, Lan Jincheng, Xu Ning, Sun Jinsheng, Meng Lingtao
College of Petroleum Engineering, China University of Petroleum (East China) Qingdao 266580 China
RSC Adv. 2020 Nov 27;10(70):43204-43212. doi: 10.1039/d0ra07504c. eCollection 2020 Nov 23.
In this research study, we modified hydroxyethyl cellulose to obtain hydrophobically associating hydroxyethyl cellulose, and grafted it onto the surface of nano-calcium carbonate to obtain a graft copolymer. The intramolecular or intermolecular associations between the macromolecular chains of the graft copolymers form different forms of supramolecular network structures, and they interact with nanoparticles to form stable structures to enhance their related properties. The structure of the obtained graft copolymer was characterized by Fourier transform infrared spectroscopy (FT-IR) and laser particle size analysis. Thermogravimetric analysis (TGA) showed the thermal stability of the graft copolymer, and the results showed that the graft copolymer obtained thermally decomposed after 370.86 °C, indicating that it has good thermal stability. Scanning electron microscopy (SEM) revealed the mechanism of the graft copolymers in drilling fluids. The fluid loss control performance and rheology of the filtration reducer were evaluated before and after hot rolling at 180 °C for 16 hours. The results showed that the graft copolymer has excellent fluid loss reduction performance, and it has good fluid loss reduction performance in fresh water, brine and saturated brine. The API fluid loss was only 6.4 mL after hot rolling at 180 °C for 16 h in the brine base slurry. Moreover, the obtained graft copolymer is easily biodegradable, has EC ≥ 30 000 and good environmental performance, and can be used in high temperature and high salt reservoir with high environmental protection requirements.
在本研究中，我们对羟乙基纤维素进行改性以获得疏水缔合羟乙基纤维素，并将其接枝到纳米碳酸钙表面以获得接枝共聚物。接枝共聚物大分子链之间的分子内或分子间缔合形成不同形式的超分子网络结构，它们与纳米颗粒相互作用形成稳定结构以增强其相关性能。通过傅里叶变换红外光谱（FT-IR）和激光粒度分析对接枝共聚物的结构进行了表征。热重分析（TGA）表明了接枝共聚物的热稳定性，结果表明所获得的接枝共聚物在370.86℃后发生热分解，表明其具有良好的热稳定性。扫描电子显微镜（SEM）揭示了接枝共聚物在钻井液中的作用机理。在180℃下热轧16小时前后对接滤失剂的降滤失性能和流变性能进行了评价。结果表明，接枝共聚物具有优异的降滤失性能，在淡水、盐水和饱和盐水中均具有良好的降滤失性能。在盐水基浆中于180℃热轧16小时后API滤失量仅为6.4mL。此外，所获得的接枝共聚物易于生物降解，具有EC≥30000且环境性能良好，可用于对环境保护要求高的高温高盐油藏。
