Preparation and mechanism of viscosification for recyclable associating polymer with low damage for fracturing

Abstract

Due to the complicated and variable formation conditions, P(AM-AA-APPEA) was developed. The viscosification mechanism was analysed via relative molecular weight, infrared spectroscopy (IR), nuclear magnetic resonance spectrum (1H-NMR), rheological properties, and scanning electron microscopy (SEM). It shows that M = 1.25*106 (M represents molecular weight). The polymer is composed of amides, hydroxyl groups and benzene rings. When the shear rate is 170 s-1 with continuous shear for 120 min at 90°, the viscosity is maintained at about 50 mPa·s. Gel breaking performance, formation damage, dynamic filtration, matrix permeability and fracture conductivity experiments show that it has easy glue breaking, low surface tension, low residue content, good compatibility and good rheological property. At 0.3% thickener concentration, the conductivity damage rate is 41.56%, the dynamic filtration coefficient is 4.24 * 10-5 m·s-1/ 2, and the permeability loss rate is 16.4%. The recovery performance experimental results show that it has good recyclability. [Received: October 22, 2021; Accepted: July 28, 2022]