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  = 10-3

  | topg    = 10-94

  | topg    = 10-3

  | 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

  | isbn    = 0-89181-602-X

  | isbn    = 0-89181-602-X

}}

}}

This article, along with articles in ''See also'', discusses seal analysis techniques. Both [[top seal]] and [[Fault seal behavior|fault seal]] are fundamental to prospect and play assessment as well as to production and field development. Despite our understanding of the variables that control seals<ref name=ch10r19>Downey, M., W., 1984, [http://archives.datapages.com/data/bulletns/1984-85/data/pg/0068/0011/1750/1752.htm Evaluating seals for hydrocarbon accumulations]: AAPG Bulletin, vol. 68, no. 11, p. 1752–1763.</ref> practical techniques are few and seal is commonly risked in an intuitive, qualitative manner. However, quantitative seal analysis, using those few techniques available, improves success ratios and reduces costly errors in field development.

Sufficiently intense [[deformation]] in excess of top [[seal ductility]] can [[fracture]] a top seal. In addition, sufficiently high pore pressures in excess of the fracture pressure can induce [[Natural hydraulic fracturing of top seals|natural hydraulic fracturing]]. Both [[top seal]] and [[Fault seal behavior|fault seal]] are fundamental to prospect and play assessment as well as to production and field development. Despite our understanding of the variables that control [[seal]]s<ref name=ch10r19>Downey, M., W., 1984, [http://archives.datapages.com/data/bulletns/1984-85/data/pg/0068/0011/1750/1752.htm Evaluating seals for hydrocarbon accumulations]: AAPG Bulletin, vol. 68, no. 11, p. 1752–1763.</ref> practical techniques are few and seal is commonly risked in an intuitive, qualitative manner. However, quantitative seal analysis, using those few techniques available, improves success ratios and reduces costly errors in field development.

==Importance of seal==

==Importance of seal==

Top seal and fault seal are important because they control the following:

Top seal and fault seal are important because they control the following:

* Presence or absence of hydrocarbons

* Presence or absence of [[hydrocarbon]]s

* [[Percent fill: controlling factors|Percent fill]]

* [[Percent fill: controlling factors|Percent fill]]

* Vertical and lateral distribution of hydrocarbons

* Vertical and [[lateral]] distribution of hydrocarbons

* [[Migration pathway]]s and [[Calculating charge volume|charge volume]]s

* [[Migration pathway]]s and [[Calculating charge volume|charge volume]]s

* Distribution and movement of hydrocarbons during field development

* Distribution and movement of hydrocarbons during field development

Seals are fundamental; no seal, no trap. Seals, or their absence, also define leak points that control the percent fill for hydrocarbon accumulations. Assessment of percent fill without the ability to risk seal (top or fault) is reduced to a statistical guessing game. They control the vertical and lateral distribution of hydrocarbons, both within individual fields and within basins.

Seals are fundamental; no seal, no [[trap]]. Seals, or their absence, also define leak points that control the percent fill for hydrocarbon accumulations. Assessment of percent fill without the ability to risk seal (top or fault) is reduced to a statistical guessing game. They control the vertical and lateral distribution of hydrocarbons, both within individual fields and within basins.

Seals control migration pathways into traps. A trap may be empty not because a fault ''leaked'' once-trapped hydrocarbons but because a fault ''sealed'' and prevented hydrocarbons from migrating into a trap and filling it in the first place. Similarly, top seals can restrict vertical migration into shallow traps and control the vertical and lateral distribution of hydrocarbons within a basin.

Seals control [[migration]] pathways into traps. A trap may be empty not because a fault ''leaked'' once-trapped hydrocarbons but because a fault ''sealed'' and prevented hydrocarbons from migrating into a trap and filling it in the first place. Similarly, top seals can restrict vertical migration into shallow traps and control the vertical and lateral distribution of hydrocarbons within a basin.

Hydrocarbons migrate until they encounter the first intact seal. Because of variations in [[Evaluating top seal integrity|seal integrity]] and [[Seal capacity|capacity]], drainage areas are four-dimensional. Prospect analysis using drainage areas defined by simple structure-depth maps on the top reservoir can be very misleading. Plays appear and disappear in response to seal behavior.

Hydrocarbons migrate until they encounter the first intact seal. Because of variations in [[Evaluating top seal integrity|seal integrity]] and [[Seal capacity|capacity]], drainage areas are four-dimensional. Prospect analysis using drainage areas defined by simple structure-depth maps on the top reservoir can be very misleading. Plays appear and disappear in response to seal behavior.

[[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]]