1393602 Seismic data processing MOBIL OIL CORP 13 July 1972 [24 Sept 1971] 32824/72 Heading H4D In the processing of seismic traces a digital seismic model of the subsurface layers producing the traces is first generated, the trace-to-trace moveout of reflection events is calculated from the model, and the traces are then stacked in accordance with the calculated values of moveout. By repeatedly changing the seismic model and iterating the calculation and stacking, the model which best depicts the subsurface layers can be selected on the basis that it gives the highest stacked signal power. In the Fig. 3 flow chart for the processing of common depth point (CDP) traces reflection travel times Ti, interval velocities Vi and dip #T/X are computed at 11 by a known "velocityby-integrated power" process. These values are used at 12 to generate offset versus travel time curves along which the traces are stacked to form a first seismic section. This section is migrated at 14 to give a digitized, layered model (depth section), by a known method. The processing can be monitored by converting the model to a travel time section at 15A for comparison at 15 with the first seismic section. At 16 a ray-tracing technique is used to compute from the model (knowing the source-toreceiver geometry, interval velocities and reflector co-ordinates), the trace-to-trace moveout of reflection events. For these values of moveout the traces are stacked at 17 to give a seismic section in which the reflection signal has been enhanced. The model is then changed, at 18, e.g. using an interactive graphics method, and steps 16 to 18 are iterated. The signal powers in the resulting stacked seismic sections are compared at 19 to identify the best seismic model.
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