University of Tabriz Hydrogeology 2588-3011 10 1 2025 08 23 Simulation of Sand Filter in Preventing Sand Production in Water Wells Using PFC3D Software Simulation of Sand Filter in Preventing Sand Production in Water Wells Using PFC3D Software 61 76 21639 10.22034/hydro.2026.68989.1337 FA Farrin Jabbari Balderlo M.Sc. Student of Hydrogeology, Department of Geology, Urmia University, Urmia, Iran. Hossein Rezaie Full Professor, Department of Water Engineering, Urmia University, Urmia, Iran. Manijeh Qara Qeshlag Assistant Professor, Department of Geology, Urmia University, Urmia, Iran. Seyed Mehdi Esmat Saatloo Ph.D. in Civil Engineering – Water, Head of Operations, West Azerbaijan Province Water and Wastewater Company, Urmia, Iran. Journal Article 2025 09 05 Groundwater resources, as essential sources for drinking water and agriculture, are vulnerable to sand production, which reduces well efficiency and damages equipment. This study investigates and optimizes gravel pack design to control sand production in production wells in southern Urmia, Iran. Geological well logs were analyzed using LogPlot to identify sand-prone layers and dominant grain sizes in each well. Critical flow discharge was calculated based on Reynolds number and Shields criterion and compared with actual pumping rates to determine high-risk wells. Gravel pack design considered the physical and hydrodynamic properties of the aquifer and was evaluated through CFD–DEM numerical simulations. Four gravel pack types were designed for coarse (14.5–18 mm), medium (5.2–7.5 mm), fine (1–4.3 mm), and very fine sand (0.65–1.1 mm and 1.2–1.5 mm, dual grading), and their performance was simulated. Results indicated that selecting appropriate grain sizes and implementing a graded gravel arrangement enhances particle stability and prevents sand migration into the well. Optimized gravel packs effectively control fluid flow and mitigate sand production, thereby increasing well lifespan and water production efficiency. This study demonstrates the importance of integrating geological data, hydrodynamic analysis, and numerical simulations for sustainable groundwater well design, providing practical guidelines for selecting gravel pack size and configuration according to aquifer properties. Groundwater resources, as essential sources for drinking water and agriculture, are vulnerable to sand production, which reduces well efficiency and damages equipment. This study investigates and optimizes gravel pack design to control sand production in production wells in southern Urmia, Iran. Geological well logs were analyzed using LogPlot to identify sand-prone layers and dominant grain sizes in each well. Critical flow discharge was calculated based on Reynolds number and Shields criterion and compared with actual pumping rates to determine high-risk wells. Gravel pack design considered the physical and hydrodynamic properties of the aquifer and was evaluated through CFD–DEM numerical simulations. Four gravel pack types were designed for coarse (14.5–18 mm), medium (5.2–7.5 mm), fine (1–4.3 mm), and very fine sand (0.65–1.1 mm and 1.2–1.5 mm, dual grading), and their performance was simulated. Results indicated that selecting appropriate grain sizes and implementing a graded gravel arrangement enhances particle stability and prevents sand migration into the well. Optimized gravel packs effectively control fluid flow and mitigate sand production, thereby increasing well lifespan and water production efficiency. This study demonstrates the importance of integrating geological data, hydrodynamic analysis, and numerical simulations for sustainable groundwater well design, providing practical guidelines for selecting gravel pack size and configuration according to aquifer properties. https://hydro.tabrizu.ac.ir/article_21639_0e6cf33ad87da572cb5dcd1e36b1807f.pdf