Abstract: Lost circulation materials may include a plurality of self-aggregating particles having a degradable coating, wherein the self-aggregating particles are capable of bonding via mechanical interactions, electrical interactions, magnetic interactions, chemical interactions, or any combination thereof into a plurality of aggregated particles. The aggregated particles have a larger effective size and can seal large openings/apertures in the subsurface that cause lost circulation during a wellbore drilling operation.

Abstract: Lost circulation materials may be particles having a core-shell structure. Said particles may include: a core comprising an expandable material; and a shell around the core, the shell comprising an outer permeable membrane, an inner permeable membrane, and a hardenable material between the outer and inner permeable membranes; and wherein the core-shell structure is folded. The particles may be initially folded where, upon exposure to a stimulus, the core expands in volume (which unfolds the particles) and the shell increases in strength. The expanded particles can then clog large openings/apertures in the formation.