Svelvik CO2 Field Lab is a small-scale field laboratory designed for the development and testing of geophysical monitoring technologies required for large scale CO2 storage applications. The site consists of an injection well surrounded by four 100m deep monitoring wells for cross-well monitoring and allows injection at 64 – 65m depth. High-resolution seismic data sets were acquired before, during and after CO2 injection. We present results investigating the distribution and migration of the injected CO2, including observed leakage at the injection well. These are based on seismic travel time analysis showing the CO2 plume during and after the injection. We also present data showing various effects of small amounts of CO2 on amplitudes and frequency spectra.