[American Constitutionalist]

In other words, to put it shortly, it's the viscosity of the oil that flows through the rock formation ? correct ? and so to speak hit up against a rock wall.
So what they do is put microscopic blasted holes in the rock to allow it to flow.
Perforating the rock.

[thackney]

Viscosity affects production rates but not so much the rate of change in the production.

Hydro frac creates cracks not holes. The sand in the franc fluid keeps the cracks from closing once the franc job is completed.