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Seal capacity and two-phase hydrocarbon columns (view source)
Revision as of 15:38, 31 January 2014
, 15:38, 31 January 2014Initial import
{{publication
| image = exploring-for-oil-and-gas-traps.png
| width = 120px
| series = Treatise in Petroleum Geology
| title = Exploring for Oil and Gas Traps
| part = Predicting the occurrence of oil and gas traps
| chapter = Evaluating top and fault seal
| frompg = 10-1
| topg = 10-94
| author = Grant M. Skerlec
| link = http://archives.datapages.com/data/specpubs/beaumont/ch10/ch10.htm
| pdf =
| store = http://store.aapg.org/detail.aspx?id=545
| isbn = 0-89181-602-X
}}
==Two phases are better than one==
Seal capacity depends on both the hydrocarbon phase and the physical character of the top seal. Since displacement pressure is a function of the seal and the coefficient of interfacial tension of the hydrocarbon phase beneath the seal, it is possible to trap a thicker two-phase hydrocarbon column than oil alone or gas alone.<ref name=ch10r92>Watts, N., L., 1987, Theoretical aspects of cap-rock and fault seals for single and two-phase hydrocarbon columns: Marine and Petroleum Geology, vol. 4, no. 4, p. 274–307., 10., 1016/0264-8172(87)90008-0</ref> The gas in contact with the base of the seal determines the displacement pressure (P<sub>d)</sub> of the seal. The buoyant effect of the oil column, however, is less than that of a pure gas column, and a greater total hydrocarbon column can be trapped.
==Single phase vs. two phase==
The following figure compares the seal capacity of a top seal with a single-phase oil accumulation, a single-phase gas accumulation, and a two-phase accumulation with both an oil leg and a gas cap. The largest hydrocarbon column is sealed by the two-phase accumulation. This best applies to traps with a geometry such that only the gas column is in contact with the seal. It also applies to fault traps.
[[file:evaluating-top-and-fault-seal_fig10-52.png|thumb|{{figure number|10-52}}After .<ref name=ch10r92 /> Copyright: Marine and Petroleum Geology.]]
==See also==
* [[Seal capacity]]
* [[Seal capacity of different rock types]]
* [[Variation in seal capacity with depth and hydrocarbon phase]]
* [[Seal thickness]]
* [[Fault-dependent leak points, continuity, and charge]]
==References==
{{reflist}}
==External links==
{{search}}
* [http://archives.datapages.com/data/specpubs/beaumont/ch10/ch10.htm Original content in Datapages]
* [http://store.aapg.org/detail.aspx?id=545 Find the book in the AAPG Store]
[[Category:Predicting the occurrence of oil and gas traps]]
[[Category:Evaluating top and fault seal]]
| image = exploring-for-oil-and-gas-traps.png
| width = 120px
| series = Treatise in Petroleum Geology
| title = Exploring for Oil and Gas Traps
| part = Predicting the occurrence of oil and gas traps
| chapter = Evaluating top and fault seal
| frompg = 10-1
| topg = 10-94
| author = Grant M. Skerlec
| link = http://archives.datapages.com/data/specpubs/beaumont/ch10/ch10.htm
| pdf =
| store = http://store.aapg.org/detail.aspx?id=545
| isbn = 0-89181-602-X
}}
==Two phases are better than one==
Seal capacity depends on both the hydrocarbon phase and the physical character of the top seal. Since displacement pressure is a function of the seal and the coefficient of interfacial tension of the hydrocarbon phase beneath the seal, it is possible to trap a thicker two-phase hydrocarbon column than oil alone or gas alone.<ref name=ch10r92>Watts, N., L., 1987, Theoretical aspects of cap-rock and fault seals for single and two-phase hydrocarbon columns: Marine and Petroleum Geology, vol. 4, no. 4, p. 274–307., 10., 1016/0264-8172(87)90008-0</ref> The gas in contact with the base of the seal determines the displacement pressure (P<sub>d)</sub> of the seal. The buoyant effect of the oil column, however, is less than that of a pure gas column, and a greater total hydrocarbon column can be trapped.
==Single phase vs. two phase==
The following figure compares the seal capacity of a top seal with a single-phase oil accumulation, a single-phase gas accumulation, and a two-phase accumulation with both an oil leg and a gas cap. The largest hydrocarbon column is sealed by the two-phase accumulation. This best applies to traps with a geometry such that only the gas column is in contact with the seal. It also applies to fault traps.
[[file:evaluating-top-and-fault-seal_fig10-52.png|thumb|{{figure number|10-52}}After .<ref name=ch10r92 /> Copyright: Marine and Petroleum Geology.]]
==See also==
* [[Seal capacity]]
* [[Seal capacity of different rock types]]
* [[Variation in seal capacity with depth and hydrocarbon phase]]
* [[Seal thickness]]
* [[Fault-dependent leak points, continuity, and charge]]
==References==
{{reflist}}
==External links==
{{search}}
* [http://archives.datapages.com/data/specpubs/beaumont/ch10/ch10.htm Original content in Datapages]
* [http://store.aapg.org/detail.aspx?id=545 Find the book in the AAPG Store]
[[Category:Predicting the occurrence of oil and gas traps]]
[[Category:Evaluating top and fault seal]]