Organic and Trace Element Geochemistry of the Ameki Formation, South Eastern Nigeria: Implications and Hydrocarbon Generating Potential

The source generative potential of the Ameki Formation in Umuahia, area, southeast Nigeria, was investigated using organic geochemical and trace element geochemistry. Results obtained from organic geochemical analysis reveal an overall organic richness with total organic carbon contents ranging from 0.28 to 4.35wt%TOC. The amount of generated hydrocarbon through cracking of the kerogen, S 2, recorded from the rock-eval pyrolysis ranges from 0.14 to 3.57wt%. This suggests low hydrocarbon generative potential. The organic matter consists predominantly of inert Type IV kerogen and insignificant gas prone Type III kerogen. Tmax values range from 391 to 423 C with an average of 413 C, which indicates source rock immaturity and no oil generative potential. Trace element geochemistry indicates that ratios of redox proxies Ni/Co and V/Cr varies from 1. 35 -6.80 and 0.74 -2.21 respectively. This may suggest that organic matter deposition in the formation took place under oxic conditions. This study therefore shows that the Ameki Formation contains mainly Type IV kerogen with no hydrocarbon generating potential; is immature and was deposited under oxic conditions.