Foraminiferal Biostratigraphy and Depositional Environment of Oloibiri-1 Well, Eastern Niger Delta, Nigeria

Foraminiferal biostratigraphy has been undertaken from the ditch cutting samples of Oloibiri-1 well located in the eastern Niger Delta. Oloibiri-1 well is composed of shale and mudstone/siltstone with intervals of sand/sandstone. Oloibiri-1 well which contains both planktic and benthic foraminifera, penetrated strata of Miocene age, and have been subdivided into biostratigraphic zones. The planktic zone established for the well is Praeorbulina glomerosa Zone. The benthic zone established is a taxon range zone of Poritextularia panamensis. Other sections of the well were barren or have sparse foraminifera content. Littoral-deltaic to marine environments of deposition have been inferred on the bases of the occurrence of environmentally restricted benthic foraminifera taxa, some which belong to the following genera Quinqueloculina, Hopkinsina, Spiroplectamina, Lenticulina, Heterolepa, Alveolophragmium and Textularia.