Research progress of lubrication performance evaluation methods for drilling fluid

Based on the principles of tribology, the lubrication types of drilling fluid involved in drilling process are introduced, including boundary lubrication, mixed lubrication, hydrodynamic lubrication, and elastic- hydrodynamic lubrication. The origin and development status of evaluation methods for drilling fluid lubricity in more than half a century are summarized, and the advantages and disadvantages of various evaluation methods are analyzed. It provides a reference for researchers and technicians in the industry to screen lubricants for drilling fluid. On this basis, it is suggested to vigorously support the development of advanced drilling fluid lubricity evaluation equipment that can be promoted on a large scale and fit the actual situation in the field, to improve the guiding value of indoor research to field applications.