We describe a portable Raman lidar system that can remotely detect oil leakages in water. The system has been developed based on a frequency-doubled, Q-switched Nd:YAG laser, operated at 532 nm with a receiver telescope equipped with some filters and photomultipliers. Stand-off detection of oil is achieved in a 6-m-long water tank, which allowed us to considerably increase the survey capability of subsea infrastructures, including both the range observation and target identification.