Derivative with respect to the logarithm of time (see Fig. 1):
p' = \frac{dp}{d(\ln t)} = t \, \frac{dp}{d t} |
Fig. 1. Example of log-derivative P' (in red) along with pressure drop P (in blue) for a typical DTR presented on PTA type-library log-log plot |
See Also
Petroleum Industry / Upstream / Subsurface E&P Disciplines / Well Testing / Pressure Testing / Pressure Transient Analysis (PTA) / PTA Diagnostic Plot
[ Well & Reservoir Surveillance ] [ Pressure Diffusion ] [ Pressure log-log plot ]