Reusing past experiences by reasoning from past cases poses particular problems when the input to case retrieval comes from large amounts of online data. Volve has developed a system in which data from oil well drilling logs are continuously monitored, interpreted, and used to check if previous incidents exist that may predict an unwanted event to happen unless preventive actions are taken. The system is currently being tested. Keywords. case-based reasoning, decision support, online data analysis, oil-well drilling Invited talk summary paper.