Thin beds have almost no impact due to destructive interference Impact of Blocking For typical seismic data, blocking on the order of 3 m (10 ft) is the recommended minimum Using coarser blocking helps identify the major stratigraphic contributors to the peaks and troughs Sonic Log Sonic Log RC Synthetic RC Synthetic - + - + Time (sec) SLIDE 11 Rather then inputting the sonic and density logs directly, we ‘block’ the logs to capture significant changes This helps us associate major lithologic changes with specific peaks or troughs The blocking process does not “corrupt” the synthetic trace As shown here within the magenta rectangle, closely-spaced reflection coefficients of opposite sign results in destructive interference and, as a result, the closely-spaced RCs have almost no response on the final synthetic trace Our experience is that logs can be blocked with a 3 m (10 ft) minimum layer spacing Thin beds have almost no impact due to destructive interference Coarse Blocking Fine Blocking Courtesy of ExxonMobil L 7 – Well-Seismic 1