Abstract: A method may include: circulating an oil-based drilling fluid though a drill string to extend a wellbore through a subterranean formation, wherein the oil-based drilling fluid comprises an invert emulsion; separating at least a portion of the oil-based drilling fluid from the circulated oil-based drilling fluid to form a separated portion of oil-based drilling fluid; mixing a metal salt and a metal oxide into the separated portion of the oil-based drilling fluid to form a chemical sealing pill; introducing the chemical sealing pill into the drill string and flowing the chemical sealing pill into a lost circulation zone in the subterranean formation; allowing at least a portion of the chemical sealing pill to set in the lost circulation zone to form a set plug, wherein the set plug seals the lost circulation zone and reduces loss of fluid into the lost circulation zone from subsequently introduced fluids; and preventing loss of fluid into the lost circulation zone from subsequently introduced fluids with the s