Stem test8 Feb 2024 06:50
The formulas cover the cases of measured and unmeasured flow rates; a short flow period with a relatively long shut-in, comparable flow and shut-in periods, and multiple shut-in tests. They solve for fully built-up pressure, formation flow resistance (transmissibility) and skin pressure, formation flow resistance (transmissibility) and skin resistance, and for flow rates when these are not measured.
The procedures are quick and easy to apply, given the appropriate pressure measurements, although checking the validity of results lengthens pressure measurements, although checking the validity of results lengthens the calculations appreciably in one case. It appears that highly precise results are obtainable by these methods for most drill stem tests causing smoothly varying single phase flow in the reservoir.