Biostratigraphy and Depositional Environments of Wells BB-3, D-01 and BL-1X Deep Offshore, Niger Delta Basin, Nigeria: Insights from Palynological Studies

Abstract

Biostratigraphic studies was carried out on BB-3, D-01 and BL-I X wells deep offshore Niger Delta Basin, Nigeria. Palynological analysis was carried out on 295 ditch cutting samples (BB- 3 = 82, D-01= 109, and BL-IX= 104). Open hole geophysical log data was also provided for the studied intervals 10700-15600 ft, 8060-16860 ft and 7900-13000 ft in BB-3, D-OI and BL-IX wells respectively belonging to the Agbada Formation. Lithologically, the section varies from alternation of sand and shale units with carbonaceous debris, mica flakes, ferruginised materials and glauconite at some interval as accessory minerals. Palynomorphs recovered from the analyzed interval were mainly Zonocostites ramonae, Monopoorites annulatus, fungal spores/hyphae, species of Sapofaceoidaepollenites and Laevigatosporites and were found to dominate the microfloral assemblage of the analyzed intervals. Sphaeromorph acritarch species of Leoisphaeridia coupled with Pediastrium, Botryococcus, Operculodinium centrocarpum, Lingulodinium machaerophorum, Achomosphaera ramulifera, Spiniferites ramosus and indeterminate dinoflagellate cysts were the marine indicators present. Samples from the section are dated early Miocene to early Pliocene age based on the independent paleontological evidences. The deduced depositional environments of the strata penetrated by the wells range from outer neritic through bathyal to deep marine.