Preparation of oligosaccharide CQ01 and its lubricity in drilling fluid

¹ Changqing Drilling Branch, CNPC Chuanqing Drilling Engineering Company Limited, Xi’an, Chian
² Xi’an Key Laboratory of Tight oil (Shale oil) Development, Xi’an Shiyou University, Xi’an, China

Abstract

Based on its good water solubility, temperature resistance and environmental protection, oligosaccharides are widely used in food and beverage, baking and medical care. In view of the poor lubrication performance of drilling fluid in ultradeep wells, long horizontal wells and highly deviated wells, and the problems of environmental protection and temperature resistance faced by drilling fluid lubricants, its application is limited. Therefore, in order to reduce its limitations and improve its application, it is necessary to study oligosaccharides. Using vegetable gum rich in oligosaccharides as raw materials, oligosaccharide CQ01 high-performance lubricant can be developed, and its action efficiency in drilling fluid can be experimentally investigated. High performance drilling fluid lubricant meeting the requirements of environmental protection and drilling engineering can be developed, and its lubrication performance, temperature resistance and compatibility can be evaluated in laboratory experiments. The results show that oligosaccharide CQ01 has multiple effects of increasing viscosity and cutting, reducing filtration and improving the lubricating performance of drilling fluid. CQ01 lubricating fluid with low content of oligosaccharide has good adaptability to drilling bentonite. The lubrication mechanism of oligosaccharide CQ01 is that the hydrophilic group (- OH) in oligosaccharide CQ01 molecule is adsorbed on the borehole wall rock surface or drilling cuttings surface to form a chemical adsorption film, resulting in the friction surface being separated by the chemical adsorption film to play the role of lubrication.