Abstract: The H3a reservoir of the deep HG group in the Z work area of the East China Sea is buried relatively deep and generally presents a low-permeability and tight background. Although there are locally developed physical sweet spots, the seismic response characteristics are not obvious, and the prediction of physical and gas properties is difficult. To address this issue, we adopt a workflow starting from petrophysical analysis to obtain reservoir-sensitive parameters based on well data. AVO analysis is combined with elastic impedance (EI) inversion using partial angle stacks to achieve sandstone characterization. According to the conclusion that \lambda\rho is most sensitive to porosity variations based on petrophysical modeling with different porosities, high-precision prestack simultaneous inversion is adopted to obtain elastic parameters for porosity prediction. A gas-sensitive attribute is finally constructed by integrating porosity and attenuation parameters for accurate gas prediction. A practical application shows that the above-mentioned methods can effectively improve the prediction accuracy of lithology, porosity, and gas accumulation. In view of their efficient support to exploration and development activities in the study area, these methods can be promoted for application in similar regions.