A method and system are described for monitoring post-stimulation operations using a plurality of communication nodes disposed along tubular members in a wellbore. The method includes constructing a communication network and installing the communication nodes along the tubular members. The communication nodes are used to monitor for the presence and/or quantity of solids and/or fluids associated with post-stimulation operations in the tubular members by analyzing how the contents of the tubular members acoustically affect the signals transmitted between the communication nodes. Hydrocarbon operations may be modified based on the analysis.