Study on oil displacement mechanism of alkyl carboxyl betaine
To explore the oil displacement mechanism of betaine surfactants,three alkyl carboxyl betaines with different alkyl chain lengths were selected for microscopic visualization oil displacement experiments.The oil-water interfacial tension(IFT)and the emulsification of crude oil were also measured.The experimental results showed that alkyl carboxyl betaines could effectively reduce the IFT and promote the in-situ emulsification of crude oil.With the increase of alkyl chain length,the IFT decreased and the emulsifying effect was enhanced.The mechanism of enhanced oil recovery by cetyl carboxyl betaine(C16BC)included the following two aspects:0.3％C16BC could reduce the IFT to the order of magnitude of 10-2 mN/m,effectively mobilize the crude oil in the pores through emulsification under weak shear,and break the columnar,porous and cluster remaining oil into oil droplets by formation of oil-in-water emulsion,which improved the oil washing efficiency.At the same time,due to the superposition of the Jamin effect generated by emulsified oil droplets,C16BC could stably produce a channel blockage effect,which increased the sweep efficiency by 20％.As an oil displacement agent exhibiting in-situ emulsification synergistic self-profile control,the oil displacement efficiency of C16BC was 42.1％higher than that of formation water flooding,which could be used to improve the recovery of chemical flooding in low-permeability reservoirs.
万方数据
维普
