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CO₂ enhanced oil recovery is a tertiary petroleum recovery process in which carbon dioxide is injected into a depleted oil reservoir to mobilize residual oil that cannot be displaced by primary production or secondary waterflooding. Under sufficient reservoir pressure and temperature conditions, injected CO₂ becomes miscible or near-miscible with the crude oil, reducing oil viscosity, swelling the oil phase, and lowering interfacial tension so that oil flows more readily toward production wells ^[1]. The process operates through mechanisms of multi-contact miscibility development, where CO₂ transfers between gas and oil phases across a transition zone and progressively extracts lighter hydrocarbons from the oil, progressively altering the phase behavior until the gas and oil become single phase at the minimum miscibility pressure. Reservoir engineering design determines injection patterns, slug size, WAG (water-alternating-gas) ratios, and reservoir pressure to optimize sweep efficiency while controlling gravity override, viscous fingering, and CO₂ breakthrough. The process simultaneously serves as a carbon storage mechanism because a portion of the injected CO₂ remains sequestered in the reservoir after field operations cease, making it a bridge between production and geologic storage objectives ^[2]. The key technical parameters are minimum miscibility pressure, MMP, minimum miscibility enrichment, residual oil saturation after waterflooding, and the storage capacity determined by pore volume and displacement efficiency ^[3].