Definition - What does Subsurface Pressure mean?
Subsurface Pressure is defined as the weight per unit area. It can be expressed as follows:
Subsurface Pressure, P = W/A or P = M x g / A.
Where P is pressure, W is the weight equivalent to product of Mass (M) and Acceleration due to gravity (g) and A is the cross sectional area.
Near the producing horizon, the subsurface pressure can be expressed in pounds per square inch gauge.
Petropedia explains Subsurface Pressure
The most commonly studied Subsurface Pressure distribution is the one that occurs in shallow sediments. There are many geological features in a subsurface like different pressure or stress zones. The Subsurface Pressure drives large volumes of hydrocarbons to the surface and it also ensures that the hydrocarbons on the subsurface do not leak inside. Since pore pressure gradients are variable, they depend on Subsurface Pressure and temperature. Over pressured formations are more common than Subsurface Pressure formations because they are found worldwide in various geological sediments.