Palynofacies Studies of Sedimentary Succession in Ogbabu-1 well, Anambra Basin, Nigeria.

Palynofacies studies of sedimentary succession in Ogbabu-1 well was carried out on ninety (90) ditch cutting samples retrieved from Ogbabu-1 well in Anambra Basin, Lower Benue trough, Nigeria with the aim of giving a detailed palynofacies study of the Ogbabu-1 Well, Anambra Basin using sedimentology and palynology as geologic tools. This was achieved by identifying the various palynological materials present and recognition of the various groups by taking counts of each specie, which aided in source rock evaluation as well as knowing the kerogen type. The identified minerals obtained from the sedimentological analysis were used to argument data from palynological analysis to carryout paleoenvironmental reconstruction. The samples ranged in depths 1000ft - 6830ft (305m - 2080m). The samples were subjected to sedimentological and palynofacies analysis. The hydrocarbon bearing formation and the spore colour index was noted. The sedimentological analysis of the ditch-cuttings was used to identify seven (7) palynofacies zones. The bulk of the lithologies encountered are shale, sand, sandy shale and shaly sand. In each palynofacies zone, most of the minerals identified include feldspar, iron oxide and mica. Two main environment of deposition delineated from palynofacies analysis are: shelfal and shallow marine environments. The shelfal environment is characterized by the occurrence of terrestrial woody plant/debris and relatively abundant of miospores. The shallow marine environment is characterized by occurrence of dinoflagellate cysts and foraminifer’s test- lining. The palynofacies analysis suggest there is relatively higher frequency of the land phytoclast, amorphous and miospores compared to marine palynomorphs abundance, which suggests a shelfal/ shallow marine environment. The spore colour index of the source rock is 4.5 which is immature to generate hydrocarbon and the kerogen suggested for this Well section is type III.

Keywords
Palynofacies; Kerogen; Sedimentology; Phytoclast; Palynomorph and Anambra Basin