Azimuthally Anisotropic EI Inversion for Fluid Indicator Driven by Rock Physic

Fracture fluid indicators (FFIs) can be used for fluid identification in fractured reservoirs. Elastic impedance (EI) inversion is a stable and efficient estimate of reservoir parameters. Rock-physics models build the bridge between the seismic response and the reservoir parameters and hence contribute to the seismic inversion and fluid identification in fractured reservoir. In this paper, we proposed a new FFI based on azimuthally anisotropic EI inversion and fractured anisotropic rock-physics models. First, we derived a new azimuthally anisotropic EI equation. Then, we built a fractured anisotropic rock-physics model used for the estimation of well-log parameters for the normal and tangential fracture weaknesses, which builds the initial background low-frequency trend of fracture weaknesses. Finally, based on the azimuthally anisotropic EI inversion method, we estimated a FFI applied to fluid identification in fractured reservoirs. A test on a real data demonstrates that the anisotropic parameters related to fracture weaknesses can be estimated reasonably and stably, and our method appears to provide an alternative available for fluid identification in fractured reservoirs.