Abstract: An exemplary activation device for a downhole tool includes an outer shell configured to sealingly engage a seat and configured to be sheared by the seat whereby the activation device can pass through the seat.

Abstract: An exemplary activation device for a downhole tool includes an outer shell configured to sealingly engage a seat and configured to be sheared by the seat whereby the activation device can pass through the seat.

Abstract: An activation device for use in a downhole well for activation of a downhole tool in the well. The downhole tool has a seat adapted to engage the activation device. The activation device can travel through a borehole of the downhole well to reach the seat. The activation device has an outer layer and a core. The material of the outer layer resists erosion by drilling fluid when the activation device is in the borehole. The material of the core is eroded by drilling fluid when the activation device is engaged in the seat. The activation device is then able to pass through the seat. There is also described a method of operating a downhole tool having a seat for engaging an activation device. The method includes the step of eroding at least a portion of the activation device with drilling fluid until it can pass through the seat.

Abstract: The invention relates to a roller assembly for a rotary roller reamer. The roller assembly includes a roller pin and a crushing roller. The crushing roller is arranged to be mounted on the roller pin and to rotate thereabout. The roller assembly is connected together so as to form a single cartridge which can be inserted into a pocket of the rotary roller reamer and secured thereto using a single fastener device.