Depth-Dependent Anisotropy from Sub-Salt Walkaway VSP Data

H011 Depth-Dependent Anisotropy from Sub-Salt Walkaway VSP Data W.S. Leaney* (Schlumberger) & B.E. Hornby (BP) SUMMARY Depth-dependent anisotropy was computed using multiple walkaway VSP lines acquired using a 26 level VSP tool resulting in a total array size of 12 900ft. Results show for the first time an estimation of depthdependant anisotropy parameters through a large (10 000ft) sequence of compacting sediments in the deep water Gulf of Mexico. The technique employed involves two inversions: the first inverts oriented two component waveforms for down and up P and Sv apparent phase slowness and polarization; the second inverts the slowness and