Comprehensive Evaluation of a Novel Re-crosslinkable Preformed Particle Gel for Conformance Control in Ultra-high Temperature Reservoirs

Abstract

Preferential fluid flow remains a major challenge in subsurface energy production and gas storage operations, resulting in excessive water production in mature oil fields, reduced heat extraction in geothermal reservoirs, and low sweep and storage efficiency in CO2-enhanced oil recovery projects. Polymer gels are widely used to mitigate high-permeability channels; however, conventional systems exhibit limited plugging efficiency and short lifetimes in ultrahigh-temperature reservoirs due to poor thermal stability. This study presents a novel ultrahigh-temperature-resistant preformed particle gel (UHT-PPG) developed for conformance control in reservoirs with temperatures of 150–275°C and severe super-K or channeling problems. The material was evaluated in terms of swelling behavior, recrosslinking capability, long-term hydrothermal stability, and plugging performance under ultrahigh-temperature reservoir conditions. UHT-PPG exhibits no swelling at room temperature and delayed swelling up to 20 days at 150°C. UHT-PPG can recrosslink to form a strong gel at temperatures above 180°C. Arrhenius analysis predicts long-term hydrothermal stability exceeding 650 days at 250°C and more than 9,000 days at 225°C. Coreflooding tests confirmed effective plugging performance in super-K models. Overall, the developed UHT-PPG demonstrates strong potential for improving conformance in ultrahigh-temperature reservoirs by combining reliable placement, exceptional thermal durability, and effective plugging of preferential flow paths.