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We have performed a series oflaboratory  rock physics testing under various pressure confining  and pore pressure as well as  temperature conditions states  to assess test  the seismic response to different CO$_2$ phases on two tight sandstone reservoir  samples of the sedimentary basin of the St. Lawrence Lowlands in Qu\'ebec, Canada. Lowlands.  Results show that the seimic velocity and amplitude can be used are able  to detect the CO$_2$ phase transition. These laboratory Laboratory  measurements have been used to calibrate a numerical the stochastic  geological model used to generate the  synthetic seimograms reproducing thevertical seismic profiling response to  CO$_2$ injection in the reservoir formations. Results show that substitution substituion  of brine by 100\% CO$_2$ is responsible for responsable of  a time-delay in the seismic traces despitevery low  permeabilities and porosities. porosities are very low. \\  Keywords: CO$_2$, ultrasonic measurements, seismic modeling, VSP, low porosity sandstones, Gassmann's model. model