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  = 10-10

  | topg    = 10-94

  | topg    = 10-11

  | 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

==Hydrocarbon against water==

==Hydrocarbon against water==

 

[[file:evaluating-top-and-fault-seal_fig10-6.png|thumb|left|{{figure number|1}}A fault is cross sealing if it juxtaposes hydrocarbon-bearing sands with water-wet sands.]]

file:evaluating-top-and-fault-seal_fig10-6.png|{{figure number|1}}A fault is cross sealing if it juxtaposes hydrocarbon-bearing sands with water-wet sands.

A fault is cross sealing if it juxtaposes hydrocarbon-bearing sands with water-wet sands, as illustrated in [[:file:evaluating-top-and-fault-seal_fig10-6.png|Figure 1]]. Both oil and gas are prevented from flowing into the sand in the hanging wall (R_d) by the cross-sealing fault.

A fault is cross sealing if it juxtaposes hydrocarbon-bearing sands with water-wet sands, as illustrated in [[:file:evaluating-top-and-fault-seal_fig10-6.png|Figure 1]]. Both oil and gas are prevented from flowing into the sand in the hanging wall (R_d) by the cross-sealing fault.

==Different hydrocarbon contacts==

==Different hydrocarbon contacts==

A fault is also cross sealing if it juxtaposes sands with different hydrocarbon contacts and/or different free water levels, as illustrated in [[:file:evaluating-top-and-fault-seal_fig10-7.png|Figure 2]]. Small differences in hydrocarbon contacts do not necessarily imply a cross-sealing fault because the capillary properties of the juxtaposed sands can create different hydrocarbon contacts even across a [[cross-leaking fault]]. Different free water levels do imply a cross-sealing fault.

 

A fault is also cross sealing if it juxtaposes sands with different hydrocarbon contacts and/or different free water levels, as illustrated in [[:file:evaluating-top-and-fault-seal_fig10-7.png|Figure 2]]. Small differences in hydrocarbon contacts do not necessarily imply a cross-sealing fault because the capillary properties of the juxtaposed sands can create different hydrocarbon contacts even across a cross-leaking fault. Different free water levels do imply a cross-sealing fault.

==Different pressures==

==Different pressures==

Different pressures across a fault imply cross seal. In [[:file:evaluating-top-and-fault-seal_fig10-8.png|Figure 3]], wells 1 and 2 are separated by a cross-sealing fault. Well 2 encountered virgin pressures in contrast to the lower pressures in the main field.

Different pressures across a fault imply cross seal. In [[:file:evaluating-top-and-fault-seal_fig10-8.png|Figure 3]], wells 1 and 2 are separated by a cross-sealing fault. Well 2 encountered virgin pressures in contrast to the lower pressures in the main field.

* [[Dip-sealing faults]]

* [[Dip-sealing faults]]

* [[Dip-leaking faults]]

* [[Dip-leaking faults]]

* [[Controls on percent fill]]

* [[Percent fill: controlling factors]]

==External links==

==External links==

[[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]]