Changes

  | part    = Predicting the occurrence of oil and gas traps

  | part    = Predicting the occurrence of oil and gas traps

  | chapter = Evaluating top and fault seal

  | chapter = Evaluating top and fault seal

  | frompg  = 10-1

  | frompg  = 10-67

  | topg    = 10-94

  | topg    = 10-67

  | author  = Grant M. Skerlec

  | author  = Grant M. Skerlec

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch10/ch10.htm

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch10/ch10.htm

==Calculation==

==Calculation==

Displacement pressure (P_d) is the pressure necessary to force hydrocarbons into the pore space of a rock and form a continuous hydrocarbon filament.<ref name=ch10r67>Schowalter, T., T., 1979, [http://archives.datapages.com/data/bulletns/1977-79/data/pg/0063/0005/0700/0723.htm Mechanics of secondary hydrocarbon migration and entrapment]: AAPG Bulletin, vol. 63, no. 5, p. 723–760.</ref> Displacement pressure, which is measured in dynes/cm², can be calculated by the following formula:

[[Displacement pressure]] (P_d) is the pressure necessary to force hydrocarbons into the pore space of a rock and form a continuous hydrocarbon filament.<ref name=ch10r67>Schowalter, T. T., 1979, [http://archives.datapages.com/data/bulletns/1977-79/data/pg/0063/0005/0700/0723.htm Mechanics of secondary hydrocarbon migration and entrapment]: AAPG Bulletin, vol. 63, no. 5, p. 723–760.</ref> Displacement pressure, which is measured in dynes/cm², can be calculated by the following formula:

:<math>\mbox{P}_{\rm d} = \frac{(2\gamma \cos \theta)}{\mbox{R}}</math>

:<math>\mbox{P}_{\rm d} = \frac{(2\gamma \cos \theta)}{\mbox{R}}</math>

==Wettability==

==Wettability==

The wettability, or contact angle θ, is 0° for hydrocarbon/water.<ref name=ch10r5>Berg, R., R., 1975, [http://archives.datapages.com/data/bulletns/1974-76/data/pg/0059/0006/0900/0939.htm Capillary pressure in stratigraphic traps]: AAPG Bulletin, vol. 59, no. 6, p. 939–956.</ref> If the wetting phase is oil or gas rather than water, the contact angle can range from 0 to 180°. Not all rocks are water wet, and oil-wet seals may not be as rare as commonly thought.<ref name=ch10r15>Cuiec, L., 1987, [[Wettability]] and oil reservoirs, in Kleppe, J., Berg, E., W., Buller, A., T., Hjemeland, O., Torsaeter, O., eds., North Sea Oil and Gas Reservoirs: London, Graham and Trotman, p. 193–207.</ref> Organic-rich sediments may be source, seal, and oil wet.

The [[wettability]], or contact angle θ, is 0° for hydrocarbon/water.<ref name=ch10r5>Berg, R. R., 1975, [http://archives.datapages.com/data/bulletns/1974-76/data/pg/0059/0006/0900/0939.htm Capillary pressure in stratigraphic traps]: AAPG Bulletin, vol. 59, no. 6, p. 939–956.</ref> If the wetting phase is oil or gas rather than water, the contact angle can range from 0 to 180°. Not all rocks are water wet, and oil-wet seals may not be as rare as commonly thought.<ref name=ch10r15>Cuiec, L., 1987, [[Wettability]] and oil reservoirs, in J. Kleppe, E. W. Berg, A. T. Buller, O. Hjemeland, and O. Torsaeter, eds., North Sea Oil and Gas Reservoirs: London, Graham and Trotman, p. 193–207.</ref> Organic-rich sediments may be source, seal, and oil wet.

==Interfacial tension==

==Interfacial tension==

Hydrocarbon/brine interfacial tension values typically range from 15–72 dynes/cm.<ref name=ch10r87>Vavra, C., L., Kaldi, J., G., Sneider, R., M., 1992, [http://archives.datapages.com/data/bulletns/1992-93/data/pg/0076/0006/0000/0840.htm Geological applications of capillary pressure: a review]: AAPG Bulletin, vol. 76, no. 6, p. 840–850.</ref><ref name=ch10r67 /><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> Laboratory studies provide interfacial tension values for a range of gas and oil compositions.<ref name=ch10r31>Firoozabadi, A., Ramey, H., J. Jr., 1988, Surface tension of water-hydrocarbon systems at reservoir conditions: Journal of Canadian Petroleum Technology, vol. 27, no. 3, p. 41–48., 10., 2118/88-03-03</ref>

Hydrocarbon/brine interfacial tension values typically range from 15–72 dynes/cm.<ref name=ch10r87>Vavra, C. L., J. G. Kaldi, and R. M. Sneider, 1992, [http://archives.datapages.com/data/bulletns/1992-93/data/pg/0076/0006/0000/0840.htm Geological applications of capillary pressure: a review]: AAPG Bulletin, vol. 76, no. 6, p. 840–850.</ref><ref name=ch10r67 /><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, DOI: [http://www.sciencedirect.com/science/article/pii/0264817287900080 10.1016/0264-8172(87)90008-0].</ref> Laboratory studies provide interfacial tension values for a range of gas and oil compositions.<ref name=ch10r31>Firoozabadi, A., and H. J. Ramey Jr., 1988, Surface tension of water-hydrocarbon systems at reservoir conditions: Journal of Canadian Petroleum Technology, vol. 27, no. 3, p. 41–48, DOI: [https://www.onepetro.org/journal-paper/PETSOC-88-03-03 10.2118/88-03-03].</ref>

==See also==

==See also==

* [[How capillary properties control seal]]

* [[How capillary properties control seal]]

* [[Buoyant pressure]]

* [[Buoyancy pressure]]

* [[Calculating maximum hydrocarbon column]]

* [[Hydrocarbon column: calculation of maximum height]]

==References==

==References==

[[Category:Predicting the occurrence of oil and gas traps]]  

[[Category:Predicting the occurrence of oil and gas traps]]  

[[Category:Evaluating top and fault seal]]

[[Category:Evaluating top and fault seal]]