Self-Granulated Thermoplastic Elastic Particles for Fracture Conformance Control of Harsh Reservoirs

Abstract

Summary To address the challenges associated with the complex preparation process of polymer particles for conformance control and the difficulties in combining injection and conformance control performance, a study was conducted on a thermoplastic elastic particle conformance control agent using polyvinyl alcohol (PVA) as the particle skeleton. The millimeter-scale elastic particles can be prepared in-situ by incorporating a hydrophobic modifier (HM) and a cross-linking agent glutaraldehyde into the aqueous phase. By adjusting the content of HM and stirring speed, the particle size can be regulated. The texture profile analysis indicated that the self-granulated thermoplastic elastic particles exhibit excellent elasticity and high resilience. Furthermore, they can undergo thermoplasticization in highly mineralized water (21×104 mg/L, Ca2+ + Mg2+ = 1.2×104 mg/L) and crude oil at 130 °C, while maintaining exceptional mechanical properties. Physical model experiments demonstrated that the particle system exhibits good migration ability and plugging performance. The particles’ breakthrough pressure significantly increased after high-temperature treatment, reaching 1860 kPa, highlighting the practical potential of these particles for oil reservoir applications. With a simple dropwise stirring "one-pot" synthesis method, the thermoplastic elastic particles offer advantages including straightforward synthesis, environmental friendliness, excellent mechanical performance, thermal stability and salt resistance. These thermoplastic elastic particles show great potential for future industrial production and have promising prospects as a fracture conformance control agent.