Self-growing biomimetic functional hydrogel particles for conformance control in tight reservoir fracture network

Hydraulic fracturing is gradually becoming a common approach for enhancing the oil production from tight reservoirs. Blocking agents such as soft particle systems are necessary as a means of conformance control to mitigate the side effect of reservoir heterogeneity due to hydraulic fracturing. In this work, a novel technique based on the mussel biomimetic concept is proposed to generate self-growing biomimetic functional hydrogel particles (SG-BFHPs). The fracture conformance control capacity of the products is evaluated, and the results show that multi-scale (0.5–3.0 mm) SG-BFHPs can cohere and grow at the reservoir condition, and the median agglomerated particle size can increase by 20–25 times. High flow resistance (Frr = 10.7–11.8), facilitated by the higher adhesion between the biomimetic particles and the pore walls, can be established by SG-BFHPs while maintaining a good injectivity. In the single-fracture model, the increased oil recovery by SG-BFHPs is about 12.2 %, and in the matrix-fracture model can be increased from 9.2 %–13.5 % to 25.8 %–28.8 %. AFM experiments show that SG-BFHPs has stronger adhesion between particles or rock surface than conventional hydrogel particles. After conformance control of SG-BFHPs, the particles are distributed in an irregular structure in the fractures and adsorbed on the fracture wall under the effect of inter-particle cohesion and adhesion, which can realize fracture channel adjustment by the particle self-growing. The SG-BFHPs studied in this paper provides valuable insights for the development of dispersed particle gel, which is of great significance in improving oil recovery in tight reservoirs.