Abstract:
Due to severe planar-heterogeneity, water-displacing-oil front in deep-water turbidite reservoirs is unstable and may cause water channeling during water flooding. In order to investigate the feasibility and enhanced oil recovery mechanisms of water and gas alternating flooding and nitrogen foam flooding in planar-heterogeneous reservoirs, artificial core samples with different permeability contrasts were designed according to the geological data in core flooding experiments. Based on the history matching of experimental data via numerical simulation, fluid flow behavior was discussed in the heterogeneous core samples. The results showed that water and gas alternating flooding presented good ability in improving sweep efficiency and reducing water cut when the permeability contrast was small; however, its ability in controlling gas mobility was depressed and the enhanced oil recovery effect was decreased when the permeability contrast was large. Due to the selective plugging of nitrogen foam and the surfactant’s improving displacement efficiency, nitrogen foam flooding could still delay fluid channeling in high-permeability streaks of severe planar-heterogeneous core samples while presented the piston-like displacement in low-permeability streaks so as to achieve in-depth profile control and oil recovery improvement. Thus, nitrogen foam flooding could effectively enhance oil recovery in deep-water turbidite reservoirs and provide technical support for the economical and efficient development of such reservoirs.