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[[file:fluid-contacts_fig3.png|left|thumb|{{figure number|3}}Example of calculating hydrodynamic fluid contacts from pressure data. Pressure elevations are shown by arrows. Calculated fluid contacts are shown by thin lines.]]

[[file:fluid-contacts_fig3.png|left|thumb|{{figure number|3}}Example of calculating hydrodynamic fluid contacts from pressure data. Pressure elevations are shown by arrows. Calculated fluid contacts are shown by thin lines.]]

A common type of nonhorizontal oil-water contact is tilting in response to hydrodynamics, the movement of water in the reservoir interval. Hydrodynamic conditions that affect fluid contacts are usually associated with active meteoric aquifers at relatively shallow depths. Indications of active meteoric flow include low salinity water, high topographic relief, and proximity to recharge areas.

A common type of nonhorizontal oil-water contact is tilting in response to hydrodynamics, the movement of water in the reservoir interval. Hydrodynamic conditions that affect fluid contacts are usually associated with active [[meteoric aquifer]]s at relatively shallow depths. Indications of active [[meteoric flow]] include low salinity water, high topographic relief, and proximity to [[recharge]] areas.

If purely hydrodynamic in origin, the fluid contact tilt can be extrapolated across the field as a flat plane that intersects the contact elevation in a minimum of three control wells. Regional fluid pressure data can be used to extrapolate the fluid contacts from the contacts measured in one or two wells. Only corrected shut-in pressures unaffected by nearby production should be used for this evaluation.

If purely hydrodynamic in origin, the fluid contact tilt can be extrapolated across the field as a flat plane that intersects the contact elevation in a minimum of three control wells. Regional fluid pressure data can be used to extrapolate the fluid contacts from the contacts measured in one or two wells. Only corrected [[Pressure transient testing#Pressure buildup tests|shut-in pressure]]s unaffected by nearby production should be used for this evaluation.

Hydrodynamic potential (''h'') is usually measured as the elevation to which water would rise in an open borehole, called the ''Potentiometric elevation''. It is calculated from the reservoir pressure by the following relationship:<br><math>h = P/(\rho_{\rm w} \times C) + (E_{\rm m} - E_{\rm r}) </math>

Hydrodynamic potential (''h'') is usually measured as the elevation to which water would rise in an open borehole, called the ''Potentiometric elevation''. It is calculated from the reservoir pressure by the following relationship:<br><math>h = P/(\rho_{\rm w} \times C) + (E_{\rm m} - E_{\rm r}) </math>