This paper addresses a critical step on the road to having in-situ reservoir agents. It targets the limiting size of these devices and endeavors to model their transport mechanisms in the rock matrix. It also details an experimental study on nanofluid coreflood experiments in the ARAB-D formation of the giant Ghawar field in Saudi Arabia. The study aims to test the feasibility and future reality for displacing molecular nanoagents in the reservoir. The testing objectives, process, and results are further detailed herein.