Overpressure prediction in shales

Abstract

Accurate overpressure detection and prediction is essential to the scientific understanding of the history and safe engineering exploitation of a sedimentary basin. We predict the velocity of shales using the Clay-Plus-Silt (CPS) model from logging measured parameters, the modeled velocity is then used as normal velocity trend to detect and predict overpressure using Eaton equation. The results show that the CPS model predicts accurate velocity in normal-pressure shales, and the modeled shale velocity can be used to detect and predict overpressure more accurately than the established normal velocity trend in overpressured wells.