Drilling fluid in Arctic permafrost needs to have good ultra-low temperature rheology, shale inhibition, hydrate inhibition and environmental protection performance. In this work, the properties of ultra-low temperature drilling fluid and additives have been evaluated by using rheology and fluid filtration tests, shale inhibition tests, hydrate inhibition tests, thermal conductivity measurements and biotoxicity tests. Thereafter, the key additives have been optimized and the ultra-low temperature water-based drilling fluid formula was developed. The results show that the base fluid, which combined NaCl and ethylene glycol (EG), can meet the requirement of freezing point in Arctic drilling, and it also has low thermal conductivity and good hydrate inhibition. Xanthan gum (XC) and hydroxyethyl cellulose (HEC) have been selected as viscosifiers, carboxymethyl starch (CMS) as filtrate reducer and polyetheramine as shale inhibitor. The drilling fluid has good ultra-low temperature rheology with the freezing point of −32 °C. Furthermore, it has low thermal conductivity, and can inhibit shale dispersion, expansion and collapse, which is conducive to the stability of wellbore in Arctic permafrost. In addition, it can effectively inhibit hydrate formation and has good environmental protection performance. The drilling fluid invented in this study can provide technical support for ultra-low temperature drilling in Arctic permafrost.

北极多年冻土中的钻井液需要具有良好的超低温流变性、页岩抑制、水合物抑制和环保性能。在这项工作中，通过流变学和流体过滤试验、页岩抑制试验、水合物抑制试验、热导率测量和生物毒性试验，对超低温钻井液和添加剂的性能进行了评估。此后，对关键添加剂进行了优化，开发了超低温水基钻井液配方。结果表明，NaCl和乙二醇（EG）复合基液能够满足北极钻井冰点要求，同时具有较低的导热系数和良好的水合物抑制作用。黄原胶 (XC) 和羟乙基纤维素 (HEC) 已被选作增粘剂，羧甲基淀粉 (CMS) 作为滤液减少剂和聚醚胺作为页岩抑制剂。钻井液具有良好的超低温流变性，凝固点为-32℃。此外，其导热系数低，能抑制页岩的弥散、膨胀和坍塌，有利于北极多年冻土中井筒的稳定。此外，它能有效抑制水合物的形成，具有良好的环保性能。本研究发明的钻井液可为北极多年冻土超低温钻井提供技术支持。膨胀和塌陷，有利于北极多年冻土中井筒的稳定。此外，它能有效抑制水合物的形成，具有良好的环保性能。本研究发明的钻井液可为北极多年冻土超低温钻井提供技术支持。膨胀和塌陷，有利于北极多年冻土中井筒的稳定。此外，它能有效抑制水合物的形成，具有良好的环保性能。本研究发明的钻井液可为北极多年冻土超低温钻井提供技术支持。