Gas hydrate reservoir identification based on modified fluid indicator

Fluid indicators derived from rock-physics play an important role in hydrocarbon detection of conventional oil and gas reservoirs ( Russell et al., 2003 ; Li et al., 2022 ), and also provide guidance for hydrate reservoir identification. The effective pore-fluid bulk modulus proves to be a more favorable fluid indicator as it eliminates the influence of porosity ( Liu et al., 2015 ). However, the use of the critical porosity model in the derivation of the effective pore-fluid bulk modulus reflection coefficient limits its application to hydrate reservoirs. Therefore, we have re-expressed the reflection coefficient equation for the effective fluid bulk modulus using the consolidation parameter and defined it as the fluid indicator of the hydrate reservoir. The model analysis shows that the accuracy of the novel fluid indicator meets the needs of the pre-stack seismic inversion, while the consolidation parameter can evaluate the consolidation and compaction of the rocks and is more meaningful for shallow subsea reservoirs. Stable prediction of model parameters is achieved using a boundary constraint inversion method proposed under the Bayesian framework. The field data application further demonstrates that the proposed method is accurate and effective in hydrate reservoir identification.