Seismic Sequence Architecture And Structural Analysis Of Northeastern Nigeria Chad (Bornu) Basin

F.E. Okpikoro, M.A. Olorunniwo
2010 Zenodo  
An elucidation of the seismic sequence architecture and assessment of the various structural trapping features common in Northeastern Nigeria Chad Basin were carried out in this study. The Chad Basin has proven petroleum reserves in sectors of other bounding countries and not same in the Nigerian sector of it. The analysis and interpretation of the data set comprising seismic reflection time sections and well logs encompassed seismic stratigraphy, structural and log-sequence stratigraphy. This
more » ... stratigraphy. This was aimed at establishing the sequence architecture and trapping mechanisms in relation to the petroleum potential of this sector of the basin. The stratigraphic succession of the Bornu Basin is sub-divisible into two genetic units that are separated by type 1 sequence boundaries. Sequence unit 1 overlies the crystalline rocks unconformably, while sequence unit 11 extends thereof to the earth's surface. Petroleum traps includes unconformity trap, lateral facies change towards structural highs, high angle normal and reverse faults, grabens, horst, and symmetrical folds. The main normal fault blocks resulted from extensional stress directed away from the main axis of the Benue Trough – Chad Basin. The fault planes and fault related features are steeply dipping which are common with rifted basins dominated by extensional stress. Consequently, they may not be sealing to petroleum migration because they could be open fractures especially at shallow depths. This makes faults associated traps in this sector of the basin to be less attractive because of high risks of drilling dry holes. The folds appear to be related to randomly distributed magmatic intrusives that underthrusted the basal sequence strata and consequently their folding into structural highs. Folding is localized and of no definite pattern and hence may not be due to regional compressional stress. The igneous intrusives could have degradational effects on petroleum pools if it occurred post-migration. The unconformity surface could act as a conduit for petroleum migr [...]
doi:10.5281/zenodo.833394 fatcat:uktub6twvvefvdlcn7vbl7zeqe