|
This work aims at
lithostratigraphic interpretation and the analysis of the
depositional environment of Nigeria Chad Basin using well
log data and seismic data. Well log data such as Gamma ray,
resistivity, bulk density and sonic logs were used to
identify lithology and stratigraphic boundaries of the
subsurface formations while the 3-D seismic data was used to
interpret the seismic facies, structures, and the nature of
the environment of deposition. Seismic to well tie was used
to validate the formation horizons identified. Lithological
descriptions ascertained five formations with alternate
sandstone and shale units, five lithofacies LF1, LF2, LF3,
LF4, and LF5 were encountered, three lithofacies
associations such as continental environment facies,
transition environment facies, and marine environment facies
were identified. Seismic attribute analysis was achieved
using structural smoothing and media filter. Seismic facies
analysis was obtained with low amplitude discontinuous
facies (Bl facies), high and low amplitude convergent facies
(Cbhl facies), high amplitude convergent (Cbh facies), and
continuous and low amplitude facies (D facies) across the
seismic volume. Structural mapping and surface seismic
attribute maps were generated from the study. It was
discovered that the Cretaceous Basement structural features
controlled the deposition of the overlying formations in the
basin.
Keywords: Seismic facies, Seismic attributes, Surface
attribute, Formation, Lithofacies
|
