There are many factors affecting the filtration of drilling fluid into the drilled formation. The adverse impact of the filtration on the well productivity calls for concerted research effort towards developing promising solutions to minimize the volume of mud filtration and solid invasion. This study investigates the potentials of perlite as a filtration control agent under high pressure conditions. Perlite is an amorphous volcanic glass that occurs naturally and abundantly. Perlite was added to a high-density barite weighted drilling fluid at different concentrations. For the different perlite concentrations, fluid loss test was conducted to form filter cakes. NMR measurements were performed before and after fluid invasion and filter cake deposition to evaluate the amount and particle size distribution of the solids that invaded the core samples. The results showed that the drilling fluid formulations containing perlite controlled filtration loss and mud particles invasion better than standard barite weighted fluids. (C) 2019 Elsevier B.V. All rights reserved.