The disclosed embodiments include methods and networks to determine a boundary of a cement mixture. In one embodiment, the method includes detecting first acoustic signals transmitted from at least one of a first plurality of acoustic tags that are mixed with cement slurry, where the cement slurry is deposited in a first section of a wellbore in an annulus between a casing and the first section of the wellbore. The method also includes determining a location of a first boundary of the cement slurry based on the first acoustic signals.