In Situ Synthesized Thermoresponsive Capsule Breakers for Controlled Fracturing Fluid Degradation

ABSTRACT A microfluidic bed reactor was developed for in situ polymerization synthesis of capsule breakers, with optimized operational parameters via theoretical modeling. Designed for a 0.1 kg/h production capacity, the reactor had a total height of 56.0 cm and a fluidized bed height of 10.0 cm. Key hydrodynamic parameters included a minimum fluidization velocity of 12.57 kg/(m 2 h) and an operational air fluidization mass flux of 603.36 kg/(m 2 h), yielding a bed cross‐sectional area of 0.004198 m 2 . The encapsulation process used ammonium persulfate as the core material, coated with acrylamide (H‐1) and acrylonitrile (H‐2). Comprehensive characterization showed H‐1 had superior encapsulation efficiency (94.9%) and temperature‐dependent sustained release, achieving 57% and 88% cumulative release at 30°C and 50°C, respectively. Thermal and mechanical analyses confirmed H‐1's enhanced gel‐breaking capacity compared to H‐2, which is suitable for hydraulic fracturing. Release mechanism studies revealed distinct kinetic profiles due to polymer matrix differences, with gel‐breaking efficacy depending on controlled oxidant release and polymer degradation dynamics. H‐1 demonstrated superior overall performance, maintaining structural integrity during storage and responsive activation under operational conditions. This study provides insights into microfluidic encapsulation design and functional performance in downhole chemical delivery systems.