Multiscale rock-physics templates for gas detection in carbonate reservoirs

• We develop multiscale rock physics templates for hydrocarbon detection.
• Bridging the gaps between elastic wave data of different scales.
• Local fluid flow theory is applied in seismic exploration in carbonates.
• Multiscale wave data help inverse fluid properties in gas reservoir.

The heterogeneous distribution of fluids in patchy-saturated rocks generates significant velocity dispersion and attenuation of seismic waves. The mesoscopic Biot–Rayleigh theory is used to investigate the relations between wave responses and reservoir fluids. Multiscale theoretical modeling of rock physics is performed for gas/water saturated carbonate reservoirs. Comparisons with laboratory measurements, log and seismic data validate the rock physics template. Using post-stack and pre-stack seismic inversion, direct estimates of rock porosity and gas saturation of reservoirs are obtained, which are in good agreement with oil production tests of the wells.