Abstract: A method may include receiving real-time data relating to drilling fluid for drilling operations that utilize a drilling fluid system that includes tanks and pumps, where the drilling operations include operations that pump the drilling fluid to a drill bit on a drillstring that rotates to extend a borehole in a formation, and where the drilling fluid flows to an annulus between the drillstring and the formation to apply pressure to the formation; detecting a tank state from a group of tank states based at least in part on the real-time data, where the group of tank states includes tank states defined with respect to one or more operations of the pumps; and detecting a change in tank volume, based at least in part on the tank state, as an indicator of an undesirable interaction between the drilling fluid and the formation