The main goal of this research is to improve velocity analysis by using dip move-out (DMO) processing in order to map boundaries in depth. The improved velocity analysis could in turn lead to better stacking, depth conversion, and migration of the data. The results are correlated with three cores that were drilled along the line.
Examples of prospect and regional vibroseis seismic reflection surveys over Australian gold deposits are presented. A prospect scale seismic survey carried out over the Marsden Cu-Au porphyry deposit successfully imaged a major thrust fault and neighbouring syncline, but did not find an extension of the deposit. Drill hole intersections of the Marsden Thrust corresponded well with the depth converted section. Problems encountered were low signal to noise due to short sweep length, and presence of multiples. Re-processing of a regional Northern Yilgarn line resulted in much better imaging of dipping reflectors associated with shear zones in the Sons of Gwalia deposit. Recognising steep stacking velocity gradients in the near surface was critical. Comparison of regional stack and migrated sections also demonstrated that subsequent high resolution line across Sons of Gwalia were too short to image the dipping shear zones. Thus regional and prospect seismic surveys need to be closely integrated in planning and interpretation.
Kabur, Nurul (BP America) | L'Heureux, Elizabeth (BP America) | Scherschel, Craig (BP America) | Johnson, Graham (Sound Seismic Solutions) | Rietveld, Walter (BP Egypt) | Keggin, Jim (BP Egypt) | Barley, Brian (BP Egypt)