Physics of Fluids, Journal Year: 2025, Volume and Issue: 37(2)
Published: Feb. 1, 2025
CO2 flooding can effectively enhance oil recovery in tight reservoirs. However, the mobilization characteristics and interlayer mass transfer mechanism of crude heterogeneous reservoirs with permeability ratio (PR) remain unclear. We simulated by fabricating artificial PR cores conducted experiments under different miscibility states. Moreover, nuclear magnetic resonance was employed to distinguish quantify high-permeability layers (HPLs) low-permeability (LPLs), revealing mechanisms. The results indicated that, compared those immiscible partially miscible flooding, yielded a higher overall recovery, continuing increase after breakthrough. This is primarily due significant efficiency LPL. At this stage, displacement becomes less effective, mechanisms, such as extraction diffusion between HPL LPL, become dominant drivers recovery. In state, oil–gas interfacial tension vanishes, thus enhancing effects. significantly promotes transfer, mobilizing contributions LPL during were quantified, that final contribution former 1.69 times greater than latter. verifies primary for breakthrough, emphasizing its critical role processes.
Language: Английский