Abstract
Well-log and Repeat Formation Tester (RFT) data were used for the detection of overpressure in
X Field in the Niger Delta, using sonic, gamma ray, density and calliper logs and RFT data.
ROKDOC software was used for the analysis of these data. And the result compared with the
RFT log data. The result shows that the onset of overpressure was observed in Wells A and B
depth below 7700ft and in Well C at a depth below 7150ft respectively. The formation pressure
gradient ranges from 0.836 psi/ft to 0.934 psi/ft for Well A, from 0.830 psi/ft to 0.928 psi/ft for
Well B, and from 0.830 psi/ft to 0.967 psi/ft for Well C. Overpressures in the study area are as a
result of compaction disequilibrium and secondary mechanism. That is the point at which fluids
are no longer being expelled effectively due to low permeability as the rock attempts to compact.
The results of the present study would be useful in assessing seal effectiveness, mapping of
hydrocarbon migration pathways, trap configuration, basin geometry, basin modelling, and safe
and economic drilling.