pressure prediction

Knowledge of formation pore pressure is not only essential for safe and cost-effective drilling of wells, but is also critical for assessing exploration risk factors including the migration of formation fluids and seal integrity. Usually, pre-drill esti-mates of pore pressure are derived from surface seismic data by first estimating seismic velocities and then utilizing velocity to effective stress transforms appropriate for a given area which are then combined with an estimated overburden stress to obtain pore pressure. So, the accuracy of velocity models used for pore pressure determination is of paramount importance. This paper briefly discusses some of the causes and mechanisms of overpressures, and then reviews the available methods of velocity model building, mentioning therein the shortcomings and/or the advantages of each