| 摘要 |
A computer implemented apparatus and method (Fig 3) for discovering hydrocarbon bearing formations yields a direct indication of hydrocarbon resulting from analyzing seismic amplitude data. The method uses an algorith m for determining a seismic attribute dip (DAD) (28) in which each sample poin t of each seismic trace in a survey is analyzed to determine a planar dip associated with the reflection point (20), and a normalized delta amplitude in the direction of dip. Displaying the DAD values in time slice or horizon sli ce (21) provides a direct indicator of hydrocarbons. The inventive method automatically analyzes each digitized data point in the survey by cross- correlating the traces reflected from a three-by-three array (21) of reflection points. This method involves cross-correlation of eight traces th at are reflected from the perimeter of the three-by-three array of reflection points (24) with the single trace reflected from the central point in the array. The correlation is carried out over a predefined time window, and for a series of lags. A dipping plane is then trial fitted to amplitude events for the nine traces, including lagged traces, so that the cross-correlation coherency of traces in the array is optimized for a particular strike and di p position of the dipping plane. The strike and dip of the optimum plane is recorded for later use in calculating the DAD value.
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