In view of the problems of low oil-steam ratio,high energy consumption and high CO2 emission of heavy oil thermal recovery,and difficult treatment of produced fluid of heavy oil cold production,a displacement fluid is prepared by using self-made viscosity-reducing displacement agent(ODA-1),with static viscosity reduction evalua-tion,performance analysis,and physical simulation experiment for extra-heavy oil cold production.The results show that increasing mass fraction and salinity of ODA-1 in displacement fluid can both effectively reduce the vis-cosity of extra-heavy oil.With mass fraction of 2%and salinity of 100 g/L of ODA-1 in displacement fluid,viscosity reduction rate reaches 70.62%after extra-heavy oil mixed with displacement fluid at mass ratio of 0.5.Extra-heavy oil spontaneously diffuses on the surface of displacement fluid,and oil and water phases automatically separate with no emulsification.Displacement simulation experiment is conducted under the conditions of permeability of about 1 000×10-3 μm2,formation temperature of 40℃and extra-heavy oil viscosity of 11 600 mPa·s,and recovery degree of displacement fluid flooding is 6.31 percentage points than that of simulated formation water flooding.Water flood-ing is followed successively by converted displacement fluid flooding,the first soak and the second soak,with re-covery degree increased by 7.48,11.70 and 7.83 percentage points respectively,and total increase of 27.02 per-centage points of water flooding.The viscosity of produced heavy oil reduces to 3 553 mPa·s at the temperature of 40℃,with viscosity reduction rate reached 61.37%.Displacement fluid is characterized by simultaneous viscosity reduction and oil displacement.There is no carbon emission during cold production process,with produced water contamination-free and recyclable.The research provides new technical approach for green cold production of extra-heavy oil.
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