Pre-drill pore pressure prediction from 1D seismic velocity profile to 3D modeling using high resolution full waveform inversion velocity (FWI): deep water offshore, West Nile Delta

Abstract

Pore pressure prediction is one of the most critical steps while planning new well delivery activity in exploration fields in order to achieve the well target by delivering a safe well. It is very important to understand the structural and stratigraphic complexity that may influence formation pressure differences in the study area. Also, it is critical to have a range of uncertainty in prediction to mitigate any kind of drilling problems and operational risks. In this case study, the target is to predict the pore pressure gradient for four proposed exploration wells in West Nile Delta Raven field. The workflow has been applied utilizing tilted transverse isotropic seismic velocity and a high-resolution full waveform seismic inverted velocity. It is important as well to compare different methodologies where each one will have its own limitations. A manually picked normal compaction trend with the conventional Eaton pressure transform method was applied and compared with a BP internal normal compaction trend with a modified Eaton (Presgraf) pressure transform method in the Predrill prediction. The pre-drill pore pressure is finally compared with the actual measured pore pressure data that yields a good match.

Optimizing Prediction of Bolt Support Drilling Pressure: A Hybrid Algorithm Approach to Screen Gaussian Process Time Series Regression Parameters

“…In earlier studies by numerous researchers, the pre-drilling pressure was primarily predicted using the seismic /3 interval velocity method. Scholars such as Khattab used high-resolution full waveform inversion velocity from 1D seismic velocity profiles to 3D modeling to predict pre-drilling pore pressure 1 . Noah and others used interval seismic velocity to predict the pre-drilling pore pressure of land oilfields 2 , while Ayodele and colleagues used tomography generated by two-dimensional seismic data to extract grid maps to delineate pre-drilling overpressure and normal pressure formation pore pressure 3 .…”