LITHOFACIES AND DEPOSITIONAL ENVIRONMENT OF CAWTHRONE CHANNEL 2 AND CAWTHRONE CHANNEL 9 OIL WELLS (NIGER DELTA) FROM WIRELINE LOGS

The wireline logs – resistivity, gamma ray and spontaneous potential – were used to evaluate the lithofacies and depositional environment of two on-shore wells in the Niger Delta (cawthrone channel 2 and cawthrone channel 9). The vertical manual interpretation method of the gamma ray log gave the distribution of sand, shale and mixed (shaley sands and sandy shales) in the ratio 1:2:1, respectively, in channel 2, and 2:3:4 in channel 9. There is the dominance of shale in channel 2 and mixed zone dominates in channel 9.

The “shale”, “ sand”, and “mixed” values of gamma ray log presented in the form of histogram, where log values were plotted against frequencies, show that, at shallow depth, there is a greater frequency or occurrence of sand when compared to shale, while much deeper into the well, shale predominate in both wells.

The Depositional Environment analysis by the correlation of the resistivity, gamma ray, and spontaneous potential log, indicate a marine to deep marine environment rich in organic matter, also shown by high irregular peaks of gamma ray logs and high resistivity values at the same interval of depths for the two wells. The two wells cut across the Akata and Agbada Formation in the Niger Delta.