Influences of structure and multi-intermolecular forces on rheological and oil displacement properties of polymer solutions in the presence of Ca2+/Mg2+

摘要

Salinity-tolerance is one of the crucial factors determining the applicability of a polymer in Enhancing Oil Recovery (EOR) process. In the current study, the rheological and oil displacement properties of four types of polymers with similar structures, including a comb polymer (KYPAM), a double tailed hydrophobic associating polymer (DTHAP), a comb hydrophobic associating polymer (CHAP) and a comb micro-block hydrophobic associating polymer (CBHAP), were comprehensively investigated. The experimental results proved that the thickening ability and salt resistance of the polymer was not significantly improved if only one intermolecular force functioned. On the contrary, multi-intermolecular forces, such as hydrophobic association and complexation, rendered a synergistic effect in the polymer solutions, through which the thickening property, salt resistance particularly Ca2+/Mg2+ resistance, and also the elasticity of the polymers were noticeably promoted. In oil displacement experiments, the EOR factors improved by CBHAP and CHAP can reach 27.1% and 18.8%, which were much higher than that of KYPAM (11.5%) and DTHAP (11.7%).