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Dynamic Data Analysis – v5.12.01 - © KAPPA 1988-2017
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Fig. 6.F.8 – Sensitivity to wellbore storage
6.F.7
Skin effect
6.F.7.a
Skin components
The total skin of a limited entry well is invariably positive due to the partial penetration.
The
mechanical skin of the open interval is the difference between the total skin and the
geometrical skin.
A variety of correlations has been presented in the literature to estimate the geometrical skin.
In Saphir the geometrical skin is determined by the difference between the model skin and the
model skin for a fully penetrating vertical well with no skin damage, thus the various skin
components adds up directly:
G T
M
S S S
At this stage one has to be careful about the convention of how the skin is defined. There are
two ways to define the Skin factor in limited entry well model, and these are accessible in the
Saphir settings page, Interpretation option, Skin tab:
Fig. 6.F.9 – Skin convention dialog in Saphir