Pore Pressure Prediction

In order to properly plan a well program and to drill a well, both safety and economically, knowledge and understanding of formation pressures and fracture gradients is essential. Formation pressure analysis is, therefore, an integral part of any drilling operation. It is one of the most important services provided by ML services, but is almost one of the, technically, most demanding.

Calculation of Bulk Density
from drilled cuttings
from sonic transit times
from density logs
Calculation of Overburden Gradient
Calculation of Formation (Pore) Pressure using Dexp method
Eaton method
Ratio method
Equivalent depth
Determinate Normal Compaction trend (NCT)
Shift Normal Compaction trend
Calculation of Fracture Pressure Gradient
Hubbert and Willis method
Eaton method

Dexp – any leftward deviation of subsequent normal trend line (shale line) indicate relative undercompaction, this is turn indicates overpressure or increase porosity.
Temperature – Theory states that a zone of low heat flow (thermal shadow) occurs prior to the overpressured zone i.e. zone of abnormally high heat flow.
Cuttings – splintery cuttings can be indicator of possible overpressured region.
Gas – changes in amount of gas are fundamental in detecting of abnormal pressured zones.
Connection and Trip gas – are typical of well imbalance and are a valuable aid to evaluating differential pressure and therefore formation pressure.
Background gas – increasing of BG indicate drilling in negative ΔP conditions or approaching imbalance.
Composition of the gas – occurrence or increased incidence of the heavier gas components is commonly observed when drilling into a transition zone.
Lost / Gain, Leak of Test, Formation Integrity Test, MDT tool, SIDPP, SICP etc.