In order to translate it to the Datum one needs to:
| 1 | Estimate gauge readings at formation top | LaTeX Math Inline |
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| body | --uriencoded--p_%7B\rm top%7D |
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using the wellbore fluid density gradient |
| LaTeX Math Block |
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| p_{\rm top}(t) = p_{\rm gauge}(t) + g \cdot \int_{z_{\rm gauge}}^{z_{\rm top}} \rho_f(z) dz |
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| 2 | Recalculate the pressure at formation top to the Datum using regional hydrostatic pressure gradient |
| LaTeX Math Block |
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| p_{\rm dat}(t) = p_{\rm top}(t) + GP \cdot (z_{\rm dat} - z _{\rm top}) |
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- :
| LaTeX Math Inline |
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| body | --uriencoded--\displaystyle p_%7B\rm top%7D(t) = p_%7B\rm gauge%7D(t) + g \cdot \int_%7Bz_%7B\rm gauge%7D%7D%5e%7Bz_%7B\rm top%7D%7D \rho_f(z) dz |
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- :
| LaTeX Math Inline |
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| body | --uriencoded--\displaystyle p_%7B\rm dat%7D(t) = p_%7B\rm top%7D(t) + GP \cdot (z_%7B\rm dat%7D - z _%7B\rm top%7D) |
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where
When wellbore fluid density is fairly constant between the gauge location and formation top then one can simplify the Datum Pressure calculation to:
| LaTeX Math Block |
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p_{\rm dat}(t) = p_{\rm gauge}(t) + g \cdot \rho_f \cdot (z_{\rm top} - z_{\rm gauge}) + GP \cdot (z_{\rm dat} - z _{\rm top}) |
See Also
Petroleum Industry / Upstream / Subsurface E&P Disciplines / Pressure Testing & Production Analysis
