Rapid self-healing nanocomposite gel crosslinked by LDH for lost circulation control

Lost circulation presents a complex challenge in drilling operations. Ascribed to the favorable remaining in fracture, strong resistance to efflux, and entire gel block rather than individual particles, the self-healing gels have been broadly applied as lost circulation material (LCM). In this study, we utilized layered bimetallic hydroxide (LDH) as a dynamic crosslinking agent to synthesize a novel nanocomposite (NC) gel through in-situ polymerization following the stripping of LDH in acrylic acid (AA) solution. LDH/PAA NC gels exhibit excellent self-healing properties, rheological strength, mechanical properties and adhesion properties, with these attributes being influenced by the LDH content. At 110 °C, the optimal LDH/PAA NC gel rapidly self-healed in bentonite mud within 1 h, revealing storage modulus (G′) of 4041 Pa, tensile strength of 8.04 kPa, and adhesion strength of 2.1 kPa. Visual plugging tests revealed that the LDH/PAA NC gel could withstand pressures up to 4 MPa, surpassing the capabilities of MA gel, which lacked self-healing properties. These findings highlight the potential of LDH/PAA NC gels as efficient LCM, offering a promising solution for controlling lost circulation during drilling operations.