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  | isbn    = 0-89181-602-X

  | isbn    = 0-89181-602-X

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Once the ductility or paleoductility of a seal is known, the amount of strain that has affected the seal must be determined. One of the most useful techniques is '''incremental strain analysis'''. Originally applied to fractured reservoirs<ref name=ch10r91>Watts, N., L., 1983, [http://archives.datapages.com/data/bulletns/1982-83/data/pg/0067/0002/0200/0201.htm Microfractures in chalks of the Albuskjell field, Norwegian sector, North Sea: possible origin and distribution]: AAPG Bulletin, vol. 67, no. 2, p. 201–234.</ref> the technique is equally applicable to top seal analysis (<ref name=ch10r70>Skerlec, G., M., 1982, Risking top seals in the Central Graben: Exxon Production Research Company internal report.</ref><ref name=ch10r71>Skerlec, G., M., 1990, SEALS: A short course for risking top seal and fault seal: Franklin, Pennsylvania, SEALS International, 600 p.</ref> Koch et al., 1992).

Once the [[ductility]] or paleoductility of a seal is known, the amount of strain that has affected the seal must be determined. One of the most useful techniques is '''incremental strain analysis'''. Originally applied to fractured reservoirs<ref name=ch10r91>Watts, N., L., 1983, [http://archives.datapages.com/data/bulletns/1982-83/data/pg/0067/0002/0200/0201.htm Microfractures in chalks of the Albuskjell field, Norwegian sector, North Sea: possible origin and distribution]: AAPG Bulletin, vol. 67, no. 2, p. 201–234.</ref> the technique is equally applicable to top seal analysis (<ref name=ch10r70>Skerlec, G., M., 1982, Risking top seals in the Central Graben: Exxon Production Research Company internal report.</ref><ref name=ch10r71>Skerlec, G., M., 1990, SEALS: A short course for risking top seal and fault seal: Franklin, Pennsylvania, SEALS International, 600 p.</ref> Koch et al., 1992).

==Incremental strain analysis==

==Incremental strain analysis==

==Empirical threshold for top seal failure==

==Empirical threshold for top seal failure==

How much strain can a top seal withstand? In a mature basin, risk assessment of the strain threshold at which failure occurs is determined empirically by analyzing successes and failures. The empirical threshold varies from basin to basin. In a frontier setting, estimates of the strain required for failure must be based on (1) laboratory data on seal properties and (2) estimates of the confining pressure and seal ductility at the time of trap formation.

How much strain can a top seal withstand? In a mature basin, risk assessment of the strain threshold at which failure occurs is determined empirically by analyzing successes and failures. The empirical threshold varies from basin to basin. In a frontier setting, estimates of the strain required for failure must be based on (1) laboratory data on seal properties and (2) estimates of the confining pressure and [[seal ductility]] at the time of trap formation.

==Limitations of incremental strain analysis==

==Limitations of incremental strain analysis==