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Ecrin v4.20 - Doc v4.20.01 - © KAPPA 1988-2011 Saphir Guided Session #8 • SapGS08- 10/11
We now have obtained all possible primary parameters from the minifrac analysis; these are
summarized in the analysis results dialog:
Fig. B02.8 • Minifrac analysis results
B02.3 • Use of the Loglog plot to confirm flow regimes
Additionally, the typical loglog plot, used with the drawdown derivative, can be used to display
and QC the observed flow regimes before and after the minifrac job. This is done by
recognizing the characteristic slopes within the drawdown derivative. The drawdown derivative
is preferred to the usual superposition derivative in minifrac analysis, and have different
characteristic slopes for the minifrac flow regimes compared to the typical ones used for
standard loglog plot analysis.
- A slope of (+1/2) corresponds to a linear flow prior to closure.
- A slope of (- 1/2) corresponds to linear flow after closure.
- A slope of (-1) corresponds to radial flow after closure.
From the minifrac analysis, we have obtained a fissure opening at 1.4 hours and a closure
point at around 3 hours. The after closure pseudo-radial flow was observed after 100 hours
and the inferred far-field mobility obtained was k/mu =0.084 md/cp.
For minifrac analysis, because we are interested only in flow behavior occurring after shut-in
time, we will set p@dt = ISIP for removing any unnecessary noises in the data due to frictional
losses gradually stopping immediately after surface flow stops, and unrelated to the closure
analysis. Right click in the loglog plot and choose ‘change P@dt= 0’: