Anisotropic PP and PSv Prestack Depth Imaging of 4C Data, Pamberi, Offshore Trinidad

摘要

In 2004, EOG Resources acquired an OBC 4C swath survey across the Pamberi-1 well location in the Columbus basin, eastern offshore Trinidad. Details of the P- and PSv-wave processing through anisotropic PrSTM were previously described (Johns et al., 2006) in which it was demonstrated there existed a qualitative correlation between derived parameters and attributes from P and Sv anisotropic migration velocities and regional geology. Under the “Future work” section of the previous publication, it was suggested that further data quality enhancement, in preparation for more quantitative rock property classification, could only be achieved from PrSDM imaging. In this paper, we present that next phase in the 4C processing, advancing the P- and PSv-wave data through anisotropic PrSDM, using cell-based tomography with a top-down layer-stripping approach. The Pamberi-1 well was used to initially constrain the anisotropy in the shallow section, with the deeper, spatial trend away from the well determined from the anisotropy derived previously in the time processing, later refined from event registration. Prior to the anisotropic PrSDM, the magnitude of shear splitting from the presence of azimuthal anisotropy is first examined to assess its potential impact on the PS data quality.