An Integrated 1-Dimensional and Seismic approach for Pore Pressure Prediction in an X– field of the Niger Delta
摘要
Pore pressure prediction is an essential input in drilling programs. An integrated rather than a single approach for pore pressure prediction delivers an accurate or near accurate results required for drilling without characteristic geohazards and enhanced cost implication. A one-dimensional prediction from petrophysical data served as an input VES-Vp regression. Prestack Depth Migration seismic was the source of Effective velocity picked from seismic semblance. The use of Dix equation was employed not only to convert effective velocity to interval velocity but to also provide the platform for the converting stacking velocity to Normal Moveout Velocity. The interval velocity served as an input data to generate the pore pressure volume of the field’s seismic gather after a checkshot from a well within the field was used to calibrate the seismic data. Results show that the integration of both log data and seismic velocity delivered a deeper pore pressure prediction of the subsurface and that of the entire seismic volume. While the use of log could deliver pore pressure at a depth of 12,521.62ft, the seismically-derived pressure could train as deep as 15,914.4ft. Pore pressure could have been predicted for deeper seismic data, the use of short cable length in acquisition and the non-availability of good data beyond 3000 ms. constrained seismic data acquisition. The field investigated is mildly overpressured.