Investigation on the Effect of Micro-structure Difference between Hydrophobic Associated Polymer and Salt-resistant Polymer on Enhance Oil Recovery

Abstract

Summary Hydrophobic association polymers and salt-resistant polymers are functional polymers with stronger viscosifying properties than common polymers such as hydrolyzed polyacrylamide (HPAM). And both of them can furtherly expand sweep volume to improve oil recovery efficiency. However, the current researches on the two types of polymers are mainly focused on the EOR effect, and there is no in-depth investigation on the differences in their microstructure. In this paper, hydrophobic association polymer HSP and salt-resistant polymer SRP were selected to evaluate, and the differences in microstructure, hydrodynamic characteristic size, migration capacity and enhanced oil recovery were compared. The results show that the HSP has a complex spatial network structure, while the SRP has a rigid coarse-straight chain structure. The HSP has stronger spatial aggregation structure corresponding to larger hydrodynamic characteristic size. Compared with HPAM, both HSP and SRP have higher adsorption retardation rate, causing the resistance coefficient and residual resistance coefficient are larger. The higher flow resistance of spatial network leads to better EOR effect of HSP. Compared with the SRP, the EOR of HSP flooding can be increased by 2.98%.