1. n. [Well Testing]

The data observed before the start of radial flow (middle-time transient data). When not dominated by wellbore storage, these data may reveal near-wellbore reservoir features including limited entry, hydraulic fracture, and dual-porosity or layering effects. Downhole shut-in greatly improves the quality of the early-time transient data.

See: bottomhole shut-in,  dual-porosity reservoir,  hydraulic fracturing,  late-time transient data,  limited entry,  middle-time transient data