According to the characteristics of high temperature(84.3℃) and low permeability of reservoirs in the Shuanghe-V block of the Biyang Sag

polymers 1630s and ZL-I with different degrees of hydrolysis are selec-ted for an experiment on oil displacement efficiency.Thanks to its high viscoelasticity

displacement efficiency of high concentration polymers is obviously higher than that of low concentration polymers.However

considering the cost

polymers of 1 600-2 000 mg/L is proposed for use.An additional experiment on displacement efficiency of different slug sizes is conducted too.The results show that the displacement efficiency of bigger polymer slug is higher than that of smaller polymer slug.However

the incremental displacement efficiency is insignificant when the slug size exceeds 0.5 PV.Therefore

the suggested size of slug should be between 0.4 PV and 0.5 PV.Comparing the experiment results before and after the maturing of the polymers

we find that polymer 1630s with low degree of hydrolysis is more favorable for this high-temperature reservoir.