A bearing mandrel, also known as a bearing packer or bearing packer mandrel, is a downhole tool used in drilling operations to help improve the performance and longevity of drill string bearings.

Drill string bearings are critical components of the drill string, helping to transmit weight and torque between different components of the drill string. However, they are also subjected to high levels of stress and wear during drilling operations, which can lead to premature failure and downtime.

To help improve the performance and longevity of drill string bearings, a bearing mandrel is used to pack fresh lubricant around the bearings, ensuring that they remain well-lubricated and protected from the harsh downhole environment.

The bearing mandrel typically consists of a hollow cylinder with a central bore that allows it to be mounted onto the drill string. The cylinder has a series of ports or slots around its outer surface that allow lubricant to flow into the space between the bearing and the mandrel. Once in place, the mandrel is rotated and pumped with fresh lubricant, which is forced into the bearing cavity and helps to flush out any contaminants or debris.

Bearing mandrels are an important tool in the oil and gas industry, helping to extend the life of drill string bearings and reduce downtime and maintenance costs.