Layer Stripping for Azimuthal Parameter Determination in Unconventional Plays

The correct imaging of Fractured Reservoirs common in many unconventional plays involves the extension of the migration algorithms to include azimuthal anisotropic (HTI) corrections. More often than not vertical anisotropy (VTI) is also present demanding the extension of the algorithms to an orthorhombic anisotropy. The set of anisotropic parameters derived in our original work (Wojslaw & Stein 2010) had a shortcoming. It overlooked the effect of the overburden, effectively describing RMS-like anisotropy and projecting (or foot-printing) into the deeper layers the effects of the shallow ones. This produces an overestimation of the anisotropy values and an incorrect fracture orientation. This paper will describe the layer stripping methodology and its applications to a real exploration situation that removes the effect of the overburden.