Abstract

The pressure of fluids within the pores of a reservoir is usually hydrostatic pressure defined as the pressure exerted by a column of water from the formation's depth to sea level. The compaction of sedimentation of impermeable rocks such as shales does not always allow their pore fluids to escape and thus support the total overlying rock column, leading to anomalously high formation pressures. The computation of pre drilling pore pressure is an integral part of well planning. The estimated pore pressure and its derivative, fracture pressure, provides mud weight to be used for drilling. If the abnormal pressures are not accurately predicted prior to drilling, catastrophic incidents, such as well blowouts and mud volcanoes, may take place.