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Line 24: − + + + + − − [[file:evaluating-top-and-fault-seal_fig10-51.png|thumb|{{figure number|10-51}}After .<ref name=ch10r92 /> Copyright: Marine and Petroleum Geology.]]
Seal capacity variation with depth and hydrocarbon phase (view source)
Revision as of 19:38, 24 February 2014
, 19:38, 24 February 2014→Seal capacity for oil and gas
==Seal capacity for oil and gas==
==Seal capacity for oil and gas==
Because the interfacial tension of gas increases at a different rate from that of oil with depth, it is possible to trap more gas than oil. The following figure shows the seal capacity (in feet) of a top seal for different hydrocarbon compositions with depth (after <ref name=ch10r92 />). Curves show the seal capacity for three different oils, ranging from 30–40° API and a GOR of 400–800. Methane has two different pressure gradients (0.7 and 0.45 psi/ft. The pore throat of the seal decreases with depth and compaction.
[[file:evaluating-top-and-fault-seal_fig10-51.png|thumb|{{figure number|1}}After .<ref name=ch10r92 /> Copyright: Marine and Petroleum Geology.]]
Because the interfacial tension of gas increases at a different rate from that of oil with depth, it is possible to trap more gas than oil. [[:file:evaluating-top-and-fault-seal_fig10-51.png|Figure 1]] shows the seal capacity (in feet) of a top seal for different hydrocarbon compositions with depth (after <ref name=ch10r92 />). Curves show the seal capacity for three different oils, ranging from 30–40° API and a GOR of 400–800. Methane has two different pressure gradients (0.7 and 0.45 psi/ft. The pore throat of the seal decreases with depth and compaction.
Below [[depth::9000 ft]], the seal capacity is greater for gas than it is for any of the oil compositions. Even above [[depth::9000 ft]], the seal capacity for gas is greater for some oil compositions. The seal capacity for gas is greatest at a normal pressure gradient and less for an overpressured gradient.
Below [[depth::9000 ft]], the seal capacity is greater for gas than it is for any of the oil compositions. Even above [[depth::9000 ft]], the seal capacity for gas is greater for some oil compositions. The seal capacity for gas is greatest at a normal pressure gradient and less for an overpressured gradient.
==Gas and oil distribution in basins==
==Gas and oil distribution in basins==