Normalised dimensionless difference between the sandface bottomhole pressure (BHP) and sandface reservoir pressure
and a model of a full-entry vertical well with homogeneous reservoir and non-damaged
near-well reservoir zone :
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S = \frac{2 \pi \sigma}{q_t} \cdot \left[ p_{wf}(t) - p({\bf r}, t) |_{{bf r} \nin A_s} \right] |
where
By definition the skin-factor is a pressure adjustment at the well-reservoir contact and does not affect pressure distribution in reservoir away from wellbore
.
The total skin is usually decomposed into a sum of two components:
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S_T = S_G + S_M |
where
| Geometrical skin, related to deviation of the well-reservoir contact from the simplest model |
| Mechanical skin, related to pressure drop caused by the near-reservoir zone formation damage |
Based on definition the wellbore pressure dynamics
of the well with
skin-factor can be writen as:
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p_{wf}(t) = \frac{q_t}{2 \pi \sigma} \, S + p^*_{wf}(t) |
where
is a model of a full-entry vertical well with homogeneous reservoir and non-damaged near-reservoir zone.
