Research Info

Polymer flooding is widely established as an effective mobility-control technology in enhanced oil recovery (EOR), yet its deployment in high-salinity and high-temperature (HSHT) reservoirs remains inconsistent and difficult to predict. Existing reviews have primarily catalogued polymer chemistries, degradation mechanisms, field cases, and simulation practices as parallel themes. While valuable, this compartmentalized approach implicitly assumes that polymer selection, degradation modeling, water quality management, and operational design are sequential and largely independent decisions. Field evidence from HSHT reservoirs contradicts this assumption. This review advances a new conceptual framework: HSHT polymer flooding is a dynamically coupled, feedback-controlled system in which chemical degradation, adsorption-desorption hysteresis, mechanical retention, injectivity evolution, and operational variables co-evolve over time. We formulate a testable hypothesis that viscosity loss and injectivity impairment in HSHT reservoirs are governed primarily by oxidative-ionic degradation and retention feedback mechanisms, rather than by intrinsic thermal stability alone. In this view, temperature acts as an accelerator within a multi-mechanism network, not as the dominant failure variable. Through systematic synthesis of laboratory experiments, pilot studies, and field implementations, we demonstrate that polymer performance trajectories in HSHT conditions are nonlinear and path-dependent. Degradation alters molecular weight distribution and charge density; these changes modify adsorption behavior and mechanical entrapment; retention shifts injectivity and shear exposure; shear accelerates further degradation. Conventional screening protocols and commercial simulators fail to capture these coupled dynamics, leading to structural optimism in recovery forecasts. Building on this synthesis, we propose a closed-loop deployment workflow that integrates polymer chemistry selection