A system can determine an accurate technical limit for a wellbore drilling operation using machine learning. A computing device can receive real-time data of the wellbore drilling operation; apply a machine-learning algorithm to the real-time data to determine a lost connection of the wellbore drilling operation; apply the machine-learning algorithm to determine correlations between the real-time data and historic drilling reports; and determine the technical limit for the wellbore drilling operation based on the correlations.