Estimated pore pressure, as used in the oil industry and mud logging

Mud logging

Mud logging, also known as hydrocarbon well logging, is the creation of a detailed record of a borehole by examining the bits of rock or sediment brought to the surface by the circulating drilling medium . Mud logging is usually performed by a third-party mud logging company...

, is an approximation of the amount of force that is being exerted into the borehole

Borehole

A borehole is the generalized term for any narrow shaft bored in the ground, either vertically or horizontally. A borehole may be constructed for many different purposes, including the extraction of water or other liquid or gases , as part of a geotechnical investigation, environmental site...

 by fluids or gases within the formation

Formation

Formation may refer to:* Formation flying, aerobatics performed with several aircraft* Formation , a high-level military organization* Tactical formation, the physical deployment of military forces-Sports:...

 that has been penetrated.

In the oil industry, estimated pore pressure is measured in pounds per square inch (psi), but is converted to equivalent mud weight and measured in pounds per gallon (ppg) or (lb_m/gal) to more easily determine the amount of mud weight required to prevent the fluid or gas from escaping and causing a blowout

Blowout

-Science and technology:*Blowout , a sudden release of oil and gas from a well*Blowout , a sandy depression caused by the removal of sediment by wind*Blowout grass is a grass that can be found on sand dunes...

or wellbore failure.