The spreadsheet gathers the data collected during a brine:CO2 flow-through experiment conducted on a synthetic sandstone core sample to present the capabilities of a novel 'multiflow experimental rig for CO2 experiments' designed and assembled at the National Oceanography Centre, Southampton. The test was configured to assess geophysical monitoring techniques in shallow tight (North Sea-like) CO2 storage sandstone reservoirs. The tests were conducted in the rock physics laboratory at the National Oceanography Centre, Southampton, during 2015, as part of the DiSECCS project with funding from the United Kingdom's Engineering and Physical Sciences Research Council (EPSRC grant EP/K035878/1) and the Natural Environment Research Council (NERC). The experiment was a steady state brine-CO2 flow-through test to replicate CO2 geosequestration conditions and evaluate geophysical monitoring techniques. The confining and pore pressure conditions were similar to those estimated for shallow North Sea - like storage reservoirs, but simulating inflation/depletion cyclic scenarios for increasing brine:CO2 fractional flow rates. The data include ultrasonic P- and S-wave velocities and their respective attenuation factors, axial strains, and electrical resistivity; also relative permeability to both fluids (CO2 and brine) is displayed as a function of pore volume times, associated to increasing CO2 to brine contents in the sample.