SEDIMENTARY SUCCESSION

One hundred (100) ditch cutting samples from OK-1 well, Greater Ughelli Depobelt, Niger Delta Basin, Southern Nigeria, collected from Research and Development Division of Shell Petroleum Development Company was subjected to lithological analysis with the aim of identifying the lithofacies, lithozones, source rocks and seal or caprocks of the analyzed section of the well. The lithological analysis was carried out between six thousand, one hundred and forty (6140ft) and twelve thousand, seven hundred and forty (12740ft). Various lithofacies, together with their associated mineral units were observed mainly by visual examination, taking note of grain sizes, shapes, color, sorting patterns, presence of plant materials and lignitemstreaks of the samples provided. Results of the lithological analysis yielded two (2) lithofacies, which include shale and sandy shale, with presence of plant materials and streaks of lignite, and as a result six (6) lithozones were established. All the lithofacies within the analyzed section of The well were regarded as potential source rocks, because they satisfied the lithological characteristics of source rocks. Seal or caprocks potential of the analyzed section could not however be totally ascertained, because the shales and sandy shales were not observed to be deposited on a reservoir rock by reason of their stratigraphic position, despite satisfying the lithological characteristics of seal or caprock. The analyzed section 6140ft- 12740ft of the OK-1 well was inferred to be the Agbada Formation (paralic sequence) of the Niger Delta Basin, by reason of depth and lithofacies within the section which are basically shale and lesser percentages of sand particles