Seismic Facies Analysis and Geomorphology Study of Deep Water Channel Complexes in Lower Congo Basin, Offshore Angola
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Deep water channels that resulted from turbidity currents are very common offshore West Africa. Turbidite currents have formed also channel complexes along the Lower Congo Basin, Offshore Angola.Turbidite channels are important but frequently complex reservoirs in the exploration, appraisal and development of deep-water facies (Mayall et al 2006). Improvements in 3D Seismic technologies have increased the understanding of seismic facies and sedimentary bodies related to deep water turbidite channel complexes. A methodological approach applied to 19km x 17km 3D seismic data area involved combination of Seismic Facies Analysis and Geomorphology study. Isoproportional Slicing method was applied to the mentioned dataset to better characterize the seismic reflections associated to channel complexes. Average RMS amplitude maps and variance attributes maps were generated to view the spatial distribution of the channel complexes in the study area. The four channel complexs identified within the study area with most of their associated geological features in a defined subinterval of interest have proven to have high sinuosity resulted from both continuous and discrete lateral migration and in some cases with a proportional vertical aggradation. Channel Complexes within the study area have also demonstrated, on seismic cross sectional views, to have high amplitude some and low amplitude for others. Channel Complex 1 presented itself with high amplitude and channel complex 2, channel complex 3 and Channel complex 4 presented themselves with low amplitude. Results achieved from the seismic facies analysis and geomorphology study have improved the understanding of the relationship between the deep water systems and the occurrence of salt tectonics of the region of study. In general it could be observed that the earlier setting of deep water deposits was stratigraphically affected later by the regional tectonics.