Abstract:

To solve the problems of difficult miscibility and low sweep coefficient in CO₂ flooding of ultra-low permeability beach-bar sand reservoir, theories and methods such as geology, seepage mechanics and reservoir engineering and by the combined methods of physical modeling and mathematical simulation are used to formulate the evaluation standard of CO₂ flooding, clarify the EOR mechanism of CO₂ flooding, form the optimum design technique adapted for the well pattern of CO₂ flooding, and optimize the policy limitation of CO₂ flooding in the demonstration zone Gao 89-1 block. It is indicated that the technology has been applied effectively. Up to now, over 2.8×10 ⁵ t of CO₂ have successfully been injected into the reservoir, and the cumulative oil increment is 6.5×10 ⁴ t, and 2.6×10 ⁵ t of CO₂ have been stored in CO₂ flooding and storage demonstration zone.

Key words: ultra-low permeability, CO₂ flooding, CO₂ emissions, optimal design, enhance oil recovery