The Application of Seismic Attributes in an Onshore Tanzanian Salt Basin

Abstract:

Widely used in petroleum exploration since the 1970s, seismic attributes have been under development into many types in order to indicate lithology, facies, or fluid content and correlate with rock properties. The information extracted using the volume attribute analysis in this study has been used to identify the occurrence of salt diapirism in the central and south onshore Mandawa Basin (Tanzania), and essentially to investigate geometries of geological lineaments.

In this study, seismic attributes such as chaos and cosine of phase were mainly used to highlight the continuity of reflectors in a 2D seismic line across the Mihambia-1 well. A possible explanation for zones of maximum chaoticness were observed whether reflector discontinuities such as fault zones, angular unconformities, channel sand bodies probably were composed by anhydrite, halite, gypsum intercalated with carbonates, as well as possible zones of fractures. The use of chaos seismic attribute in certain parts of the 2D seismic line highlighted the amplitude higher than 0.60 where the salt structure was interpreted. The cosine of phase attribute detected showed evidence for the continuity of the reflectors as the resolution to interpret a salt dome in central Mandawa Basin.

The application of seismic attributes technique, in addition to standard seismic stratigraphic practices, has resulted in the identification and interpretation of the occurrence of salt diapirism. The concentration of 2D seismic lines in the central and south Mandawa Basin permitted essentially to investigate geometries of geological lineaments.