Abstract

The formations in the Niger Delta-Nigeria consist of sands and shales with the former ranging from fluvial (channel) to fluviomarine (Barrier Bar), while the latter are generally fluviomarine or lagoonal. These Formations are mostly unconsolidated and it is often not feasible to take core samples or make drill stem tests. Formation evaluation is consequently based mostly on logs, with the help of sidewall samples and wireline formation tests. From the comparison between the FDC/CNL (Formation Density/Neutron Logs spell out) separation and SWS (sidewell sample) petrophysical data, it is possible for fluid differentiation to be done from SWS measurement with a good measure of reliability, in the absence of production data and FDC/CNL logs. This may not apply to liquid – rich gas and condensate reservoirs. The FDC/CNL log responses are better defined in thick clean sands as against thin marginal sands in this case study.

Key words: Formations, Gas/Oil, Sands and Shales, Hydrocarbon, Porosity, Resistivity.