An apparatus detects a fluid flow. The apparatus includes a nuclear magnetic resonance (NMR) tool configured to perform an NMR measurement on the fluid in a sensitive volume by establishing a magnetic field in the sensitive volume and transmitting a sequence of refocus pulses, without a tipping pulse, the NMR measurement comprising spin echo signals. The apparatus also includes a processor configured to detect a presence of the fluid flow in the sensitive volume based on the spin echo signals.