Changes

==Gravity drainage==

==Gravity drainage==

Gravity drainage, or gravity segregation, is the tendency of oil, gas, and water to segregate in a reservoir during production due to their differing densities (Figure 7). As a secondary drive mechanism, gravity drainage occurs only in combination with one or more of the primary oil reservoir drive mechanisms.

[[file:drive-mechanisms-and-recovery_fig7.png|thumb|{{figure_number|7}}Fluid segregation by gravity damage.]]

[[file:drive-mechanisms-and-recovery_fig7.png|thumb|{{figure_number|7}}Fluid segregation by gravity damage.]]

Gravity drainage, or gravity segregation, is the tendency of oil, gas, and water to segregate in a reservoir during production due to their differing densities ([[:file:drive-mechanisms-and-recovery_fig7.png|Figure 7]]). As a secondary drive mechanism, gravity drainage occurs only in combination with one or more of the primary oil reservoir drive mechanisms.

Conditions conducive to gravity drainage include thick reservoirs with high vertical permeabilities or thin reservoirs with steep dips. In a solution gas drive reservoir perforated down dip, gravity drainage can cause released solution gas to migrate upward and oil to flow downward, conserving reservoir energy and increasing recovery to near that of a water drive.

Conditions conducive to gravity drainage include thick reservoirs with high vertical permeabilities or thin reservoirs with steep dips. In a solution gas drive reservoir perforated down dip, gravity drainage can cause released solution gas to migrate upward and oil to flow downward, conserving reservoir energy and increasing recovery to near that of a water drive.