Evaluation of Methods to Quantify Pore Pressure Uncertainty from Geophysical Well Logs

n’s equation and porosity indicating logs (e.g., resistivity and acoustic slowness) can be used to calculate pore pressure, presuming overpressure was generated by undercompaction. Pore pressure uncertainty is considered a valuable attribute to the pore pressure model, especially in challenging drilling environments. This study evaluates three different approaches to predict pore pressure uncertainty from variations in the normal compaction trendline. One statistical and two geometrical approaches yield slightly different results for the calculated uncertainties. It is best to incorporate all results in an integrated analysis to produce the most reliable interpretation of pore pressure uncertainty. As the uncertainties are well below 0.2 g/cm³ equivalent mud weight in the undercompaction zone, the methods prove their applicability to challenges like drilling in narrow pressure windows.