US Patent 11473398 Fluids having increased magnetic permeability for subterranean tool activation

Fluid flows, such as slurries, conditioning fluids, spacer fluids, or the like, may be modified to carry materials having high magnetic permeability characteristics that can be detected by a magnetic permeability sensing apparatus positioned along the fluid flow path in wellbores or downhole tools. Sensed presence of the high magnetic permeability material by the sensing apparatus positioned in the fluid flow path may result in initiation of an operational event. The operational event may include, but not limited to closing or opening a valve, moving a component, conveying a signal, activating or deactivating a device, or the like.