A viscoelastic‐healing suspension sealing material with a double‐network gel structure for improving borehole‐sealing performance

Abstract

Developing a high‐performance sealing material to improve the sealing quality of extraction boreholes is of great significance for achieving efficient coalbed methane (CBM) extraction and safety mining. In this work, a viscoelastic‐healing suspension sealing material (VEHS) with a double‐networked gel structure was developed, consisting of a latex emulsion (LE) and polymeric superabsorbent (PSA) with the addition of fly ash (FA) and sodium montmorillonite (Na‐MMT). X‐ray diffraction, scanning electron microscopy, and rheometer tests were conducted to characterize the variation in the microstructural characteristics and rheological behaviors of VEHS, respectively. Besides, response surface methodology was utilized to model the relationships between the composition of VEHS and its viscosity and fluidity. The results show that the VEHS's structure is uniformly dense. The viscosity of VEHS, a pseudoplastic fluid, decreases progressively with an increasing shear rate while rising and stabilizing over time. Within the stress range of 10–30 Pa, VEHS exhibits relatively balanced viscoelasticity. VEHS shows excellent fluidity and can form a viscoelastic‐healing coagulated layer that is firmly adhered to the coal wall, leading to a strong sealing ability. The research has the potential to enhance the effectiveness of CBM extraction and brings the advantages in terms of safety, economy, and society.