Seismic rock physics modeling of fractures and fluids in a tight gas sandstone reservoir

Tight sandstone gas reservoirs have characteristics of low porosity and low permeability, complex pore structure. In the paper, we consider the pore and micro-fracture systems in tight sandstone reservoir and perform rock physics modeling of sandstone gas reservoirs based on Chapman.Then we analyze the effects of relaxation time, and difference fluid types on dispersion and attention, and seismic responses.We found that the magnitude of the relaxation time is related to the gas saturation and the viscosity coefficient of the fluid. The magnitude of the relaxation time affects the frequency range of the velocity dispersion and attenuation, and the type of fluid affects the magnitude of the velocity dispersion and attenuation. As the relaxation time decreases, the calculated amplitude deceases. And the amplitude and the waveform of the synthetic seismic record are related to different fluid types and formation thickness.