A review on tribology, characterization and lubricants for water-based drilling fluids

The challenges associated with drilling large displacement horizontal wells are numerous, and their adverse effects can lead to severe damage or even shut down of the drilling operation. Frictional torque of the tubular column is one of the most common problems encountered when applying water-based drilling fluids to the drilling of extended reach wells. This is because during the drilling process, there is continuous friction between the drilling tool and the rock. When water-based drilling fluid cannot effectively reduce friction, it will cause difficulty in lifting or lowering the drilling tool, resulting in sticking, and thus affecting the drilling operation. Most petroleum engineers use different lubricants to reduce friction and wear during drilling. The purpose of this study is to present the friction and lubrication state during drilling, the mechanism of action of boundary lubrication, lubrication evaluation and analysis methods, and friction reduction and wear resistance related to water-based drilling fluid lubricants reported in literature for reducing friction. Based on the review, we recommend a broad evaluation of lubricants using different lubricity performance evaluation methods to determine the true lubricity performance in the coexistence of multiple frictions during drilling. In addition, we recommend that future researchers enhance the application of numerical simulations in the analysis of lubricant lubrication mechanisms to address the difficulty of direct experiments in boundary lubrication laboratories. Any experimental program requires at least five characterization techniques, including friction coefficient, wear resistance testing, scanning electron microscopy, energy dispersive X-ray spectroscopy, and electron spectroscopy, to provide a detailed understanding of the friction reduction mechanism of the lubricant used. Lubricants based on bionic technology with good water solubility, low biotoxicity, and easy biodegradability are highly encouraged because of their availability and good lubricating properties.