Use of rock?physics analysis of well logs to determine compaction history of Cretaceous shales in the Rovuma basin, Offshore Mozambique

Cretaceous shales from the emerging gas province of Rovuma basin are examined using well-log data two exploration wells. The P-wave acoustic impedance (AIp) were estimated, and then brittleness ductility assessed within framework Reuss–Voigt limits for impedance. We predicted shale consolidation a weighting function (Wc) which varies between 0 case grains in suspension (the Reuss limit) 1 consolidated rock or cemented Voigt limit). At limit, formation AIp is highly sensitive to pressure while at limit insensitive pressure. For wells this study, most plot close lower bound with Wc < 0.5, hence showing significant sensitivity Although dominated by mechanical compaction regime, some onset chemical observed. rock-physics analysis showed that same these had very distinctive contrasting elastic properties. deeper well interval clearly shows ductile shallower range brittle behaviour matching diagenesis temperatures >58°C. These differences development rate likely due contrasts burial have important implications future seismic studies.