Summary

A new seismic inversion method, Ray-Based Stochastic In-version (RBSI) is presented, which is founded on the high-frequency Asymptotic Ray Theory (ART) description of seismic waves and firmly links Kirchhoff-Helmholtz pre-stack depth migration (PreSDM) with Stochastic Inversion (SI) for reservoir properties. Results from synthetic data tests show that: (1) RBSI, contrary to SI, can correctly determine lateral layer-density variations, a requirement for preserved-amplitude PreSDM, and (2) RBSI can delineate the correct reservoir properties in cases where SI produces erroneous results because of dip-dependent migration stretch. Ray-Based Stochastic Inversion Principle For RBSI, the subsurface space X R3 with surface boundary ∂X is parameterised as an overburden macro-model overlying a layered target reservoir sequence (Fig. 3) and is assumed t