A microfluidic apparatus for measuring thermo-physical properties of a reservoir fluid includes a first substrate defining a microchannel, an entrance well, and an exit well. The microchannel extends between and is in fluid communication with the entrance well and the exit well. The apparatus further includes a second substrate attached to the first substrate to form a microfluidic device. The second substrate defines an entrance passageway in fluid communication with the entrance well and an exit passageway in fluid communication with the exit well. The entrance passageway is configured to receive the reservoir fluid under pressure. A method of measuring thermo-physical properties of a reservoir fluid includes introducing the fluid under pressure into a microchannel and determining the thermo-physical properties of the fluid based upon the size and concentration of the bubbles formed as the fluid flows through the microchannel.