Normalised Normalised dimensionless difference between the actual drawdown wellbore pressure difference between the sandface bottomhole pressure (BHP)
and a model of a full-entry vertical well with homogeneous reservoir and non-damaged near-reservoir zone and the sandface reservoir pressure :\displaystyle p({\bf r}, t) |_{r = r_w} |
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at the well-reservoir contact. LaTeX Math Block |
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S_G = \frac{2 \pi \sigma}{q_t} \left([ p_{wf}(t) - p*_{wf}(({\bf r}, t) |_{r = r_w} \right)] |
where
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It characterises the pressure drop at well-reservoir contact due to well-reservoir contact geometry.
The geometrical skin is negative for fractured wells and slanted.
It also negative for horizontal wells when lateral permeability is not much lower than vertical.
The geometrical skin is positive for limited entry wells. – formation transmissibility