US Patent 9441470 Self-locating downhole devices

A technique that is usable with a well includes deploying a plurality of location markers in a passageway of the well and deploying an untethered object in the passageway such that the object travels downhole via the passageway. The technique includes using the untethered object to sense proximity of at least some of the location markers as the object travels downhole, and based on the sensing, selectively expand its size to cause the object to become lodged in the passageway near a predetermined location.