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Fracturing fluid flow back 375
Figure 12.34 Effect of the shut-in post-flow-back on k ro in a nondesiccated model.
12.5 Shut-in time effect on fracture conductivity
To evaluate the shut-in or delay effect, Crafton and Noe (2013) used
the well performance metric of connectivity between the reservoir and the
wellbore, as measured by “apparent fracture length.” In their opinion, the
apparent fracture length is not indicative of any measurable entity in the
reservoir or adjacent to the wellbore; it is a surrogate to describe the degree
of connectivity between the reservoir and the wellbore, nothing more.
Crafton and Noe (2013) reviewed 270 wells’ performance in the Marcel-
lus shale. The effect of delay or the first shut-in immediately starting at the
end of stimulation is presented in Fig. 12.36. In the figure, the apparent frac-
ture length is normalized by being divided by the millions of pounds of
proppant used; ITM is the abbreviation of Interfacial Tension Modifier;
the data are from the clean-up wells (thus the length is the best apparent frac-
ture length); the log of the normalized length versus the log of delay (soak)
