5. Depth conversion
Existing depth maps for the unconformable surfaces U1, U2 and U3
were derived fromaverage velocitymaps using time/depth relationship
of each unconformity. This methodology has been employed, as
follows:Depth map = velocity map × TWT map / 2000 (The TWT map
is established in ms).
The velocitymap generated at the top of the unconformity U1 shows
an average velocity increasing from northeast to southwest resulting of
thick Cretaceous and Tertiary section to the southwest (Fig. 7). The
velocity map at the top of U2 unconformity presents a heterogeneous
distribution of velocity values indicating average thickness of Late
Cretaceous and Tertiary deposits (Fig. 8). Compared to the U1 velocity
map, the values of U3 map (Fig. 9) show the inverse extending of
average velocity with an increasing from southwest to northeast as
consequence of the Late Cretaceous tectonics.