Investigation on Tribological Behavior of Glyceride-Filled Microcapsules as Additives in Water-Based Drilling Mud

Excessive torque on tool surfaces resulting in friction and wear in the process of well drilling remains a big challenge for the oil and gas exploration industry. In this study, two kinds of glycerides are encapsulated and serve as lubrication additives to improve the tribological properties of water-based drilling mud. It is found that encapsulation improved the thermal stability of microcapsules. In addition, tribological experiments were carried out using a ball-on-disc tribometer. Results revealed that glyceryl monostearate (GMS)-filled microcapsules largely improved the tribological properties of drilling mud compared to empty microcapsules and glyceryl tristearate (GTS)-filled microcapsules and contributed a protective film on the worn surface formed by released lubricants. However, increasing the amount of lubricant additives failed to further improve the friction reduction performance. Moreover, a remarkable decrease in damage and wear cracks indicated excellent antiwear properties of GMS-filled microcapsules.