Oil-based foams hold significant potential for enhancing oil recovery and regulating subsurface fluid flow, yet their stability under high-temperature reservoir conditions and their transport mechanisms within pore-throat structures remain insufficiently understood. To address this gap, this study systematically investigates the behaviour of an oil-based foam system through temperature-dependent stability experiments, complemented by pore-scale numerical simulations that characterize bubble deformation and breakthrough within porous media. Experimental results show that increasing temperature accelerates liquid drainage and gas diffusion within the foam films, leading to a reduction in the number of bubbles, enlargement of average bubble size, and a pronounced decline in overall foam stability. Simulation results further demonstrate that pore-throat diameter and injection pressure jointly govern bubble morphology evolution and breakthrough behaviour, with the competition between capillary forces and external driving pressure emerging as the key mechanism influencing oil-based foam mobility. By integrating these findings, this work establishes a unified mechanical framework linking temperature effects and pore-throat confinement, thereby providing theoretical support for the application and optimization of oil-based foams in high-temperature reservoirs.