Palynomorph Biostratigraphy of VIC 97 Well, Nothern Depo Belt, Niger Delta, Nigeria

Abstract

Palynological and sedimentological studies were conducted on sixty ditch cutting rock samples from interval 460 to 4550 feets of VIC-97 well, located at OML 38, Northern Depo-belt, Niger-Delta, to delineate lithofacies units and the age of the rock succession. Standard methods of palynological sample analysis were used to disaggregate the palynomorphs from the rock matrix. Log signatures, sand/shale ratios, textural attributes, and accessory mineal compositions of ditch cutting rock samples were used as lithologic parameters to establish two lithofacies units; the transitional unit having a sand/shale ratio of 80:20 and the continental Unit having a 98:2 ratio ascribed to upper Agbada and Benin formation respectively. Palynological analysis revealed that the retrieved palynomorphs were numerous and reasonably diversified, particularly in the lower portion of the sample interval. Palynological zonation was based on the palynofloral assemblage of important species and their stratigraphic distribution. Thirteen informal biozones were recognised on the basis of their first and last downhole occurences and compared with P 560, P580 and P624 to delineate an early to late Oligocene age for the studied interval.