Abstract:
An integrated approach to sequence stratigraphic interpretation of ‘Freeman Field’ in the deepwater
setting offshore Niger Delta has been carried out through seismic sequence, seismic facies
analyses and well calibration using both 3-D seismic data and well-log data in a view to
determining the hydrocarbon potential of the study area. Seismic facies were characterized using
seismic reflection amplitude and continuity, internal reflection configuration and external
geometry, and the nature of the bounding surfaces. The analyses identified two sequence
boundaries and three depositional sequences, and revealed the extensive presence of depositional
elements and facies. Among the facies identified are; (1) amalgamated channel sand facies, (2)
channel levee/overbank deposits, (3) hemipelagic drape facies (4) basin floor splays sheet or
distributary channel complexes, and (5) debris-flow deposits. Each depositional element displays
a unique morphology and seismic expression. The reservoir architecture of each of these
depositional elements is a function of the interaction between sedimentary process, sea-floor
morphology, and sediment grain-size distribution. Stratigraphically, the deep-water basin-floor
successions are characterized by mass-transport deposits at the base, overlain by turbidite splay
deposits and subsequently by leveed-channel deposits. Upper section of this succession is a
hemipelagic drape condensed-section deposits. This succession can be related to a cycle of
relative sea-level change and associated events at the corresponding shelf edge. Sand-prone
facies among the deposits represents potential reservoirs for the accumulation of hydrocarbon,
and hence are marked exploration targets. A combination of stratigraphic and structural play has
been interpreted for the basin floor sheet sand deposits in this study. Sand facies in single
confined channels with amalgamated sand deposits are also potential sites for the accumulation
of petroleum hydrocarbon.
