--> Abstract: Application of Sequence Stratigraphy to Reservoir Delineation and Description in the Central OML 33, Niger Delta, by O. R. Ojo; #90925 (1999)

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OJO, OLADIPO RUFUS, Obafemi Awolowo University, Dept. of Geology, Ile-Ife, Osun State, Nigeria

Abstract: Application of Sequence Stratigraphy to Reservoir Delineation and Description in the Central OML 33, Niger Delta

Sequence stratigraphic analysis was performed on Shelf's OML 33, western Niger Delta concession. The approach has been used as predictive tool to delineate reservoirs as well as describe its evolution. The data used include suite of well logs, two-dimensional seismic sections, and biostratigraphic data.

Three sequences, which fall within two of the cyclical depositional cycles (9 and 10) that make up the sequence framework of Niger Delta, have been recognized in the area, These sequences are composed of three marine transgressive shale markers: Nonion 4 (10.4 Ma), Uvigerina 8 (9.5 Ma), and Un-named shale (7.4 Ma). The producing reservoirs within the area are located within the highstand systems tract (HST) and transgressive systems tract (TST) of sequences II and I respectively. The TST reservoirs are interpreted to be deposited as reworked sand bars within shallow marine environment. The HST reservoirs are made up of stacked sand bodies probably deposited as fluvial channel-fills in an environment deduced to be shallow water (proximal fluviomarine).

The lowstand systems tract (LST) of sequence I is assigned high priority potential for play and prospect generation for several reasons. These include, ease of assignment of geometry and depositional environment to the reservoir units, and stratigraphic trapping potential. The study revealed additional possibilities (unconfined and confined channelized sand lobes) in the untested LST of the area of study. 

AAPG Search and Discovery Article #90925©1999 AAPG Foundation Grants-in-Aid