Controlling the flow path of injected fluids in layered heterogeneous oil reservoirs remains a critical challenge for enhancing the performance of gas-based enhanced oil (EOR) recovery processes. Foaming the injected gas is a promising method to address this challenge by creating selective flow resistance and improving fluid diversion. Foam generates resistance in high-permeability layers, effectively diverting injected fluids toward lower-permeability zones and improving sweep efficiency. To optimize this process, a pore-scale understanding of foam flow behavior and the underlying mechanisms of fluid diversion is essential. In this study, the flow behavior of foam was investigated under two conditions: (1) in the absence of oil (simulating aquifer conditions) and (2) in the presence of water-flood residual oil. A micromodel with two interconnected layers of contrasting permeabilities was designed to simulate layered heterogeneous porous media. Results demonstrated that in the absence of oil, foam generation effectively diverted the injected fluid flow into the lower-permeability layer. In the presence of oil, foam effectively controlled the injected gas front, significantly increasing residual oil production from 3% to 75%. These findings support the significant potential of foam to enhance gas-based EOR processes and increase incremental oil recovery. This study also highlights foam injection as an effective strategy for controlling fluid flow paths in layered heterogeneous porous media and significantly boosting residual oil production. By increasing fluid viscosity and flow resistance in high-permeability layers, foam diverts fluids to low-permeability zones, thereby enhancing the efficiency of gas injection processes.