Shut-in formation pressure estimate

Wellbore sandface pressure after a given well is shut-in for $//<![CDATA[ \begin{array}{l}t_e\end{array} //]]>$ hours

This definition is based on the practical observation of wellbore pressure in shut-in wells for well intervention purposes.

It is the simplest and the most popular definition of formation pressure and is widely used in all upstream industry applications.

The definition of shut-in time $//<![CDATA[ \begin{array}{l}t_e\end{array} //]]>$ is specific to each field or sometimes field area depending on the rock properties and the past well intervention experience.

Some conventions are to pick $//<![CDATA[ \begin{array}{l}t_e\end{array} //]]>$ at the end of the radial flow, as the most common number from the past pressure tests, which makes this definition close (but still not equal) to the (Drain-boundary formation pressure @ model:1)