Definition - What does Pore Pressure mean?
Pore Pressure is the pressure of hydrocarbons within the pores of a hydrocarbon reservoir. Pore Pressure is at times the hydrostatic pressure which is exerted by the water column from the depth of a hydrocarbon formation up to the sea level. When the sediment rocks are compacted, the pore fluids are trapped inside and exert a tremendous amount of porous formation pressure.
Petropedia explains Pore Pressure
Pore Pressure can be determined by the following methods:
Equivalent Depth Method– This method assumes that to a certain depth, Pore Pressure is hydrostatic and rock sediments are normally compacted. A Normal Compaction Trend (NCT) is plotted from which Pore Pressure can be computed.
The Ratio Method– In this method Pore Pressure is estimated by multiplying hydrostatic pore pressure by the ratio of measured depth value and normal depth value.
Eaton’s Method– In this method Pore Pressure is estimated by expressing it to the equivalent densities.
Resistivity method with NCT (Depth Dependent)– This method makes use of a relationship between measured resistivity and organic matter buried depth to estimate Pore Pressure along with plotting normal compaction trend for resistivity.
Sonic method with NCT (Depth Dependent)– It makes use of the time taken by sonic waves in the formation having normal Pore Pressure.
Effective Stress Method– This method makes use of plotting porosity versus depth curves, pressure versus depth curves and porosity versus Log Effective Stress to determine the Pore Pressure of the formation.