Changes

  | part    = Traps, trap types, and the petroleum system

  | part    = Traps, trap types, and the petroleum system

  | chapter = Classification of exploration traps

  | chapter = Classification of exploration traps

  | frompg  = 2-1

  | frompg  = 2-26

  | topg    = 2-42

  | topg    = 2-28

  | author  = Richard R. Vincelette, Edward A. Beaumont, Norman H. Foster

  | author  = Richard R. Vincelette, Edward A. Beaumont, Norman H. Foster

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch02/ch02.htm

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch02/ch02.htm

  | isbn    = 0-89181-602-X

  | isbn    = 0-89181-602-X

}}

}}

Fracture traps are divided into three classes: extension, shear, and complex, based on the internal characteristics and geometry of the fractures that make up the reservoir. The outline below shows the classes, some subclasses, and possible styles into which these traps may be subdivided.

[[Fracture]] traps are divided into three classes: extension, shear, and complex, based on the internal characteristics and geometry of the fractures that make up the reservoir. The outline below shows the classes, some subclasses, and possible styles into which these traps may be subdivided.

==Outline==

==Outline==

! Regime || Class || Subclass || Style

! Regime || Class || Subclass || Style

|-

|-

| rowspan = 12 | ''Fracture trap''; Lateral boundaries of the trap are provided by change from fractured reservoir to unfractured or less fractured rock or by change from open, permeable fractures to cement-filled or narrow-aperture, low-permeability fractures. || rowspan = 4 | ''Extension fracture trap''; Dominant reservoir fractures are extension fractures. || rowspan = 2 | ''Parallel fractures''; Open fractures in a fractured reservoir, predominantly unidirectional in both strike and dip. || ''Mineralized fracture''; Partially or totally mineralized by postfracture cements, typically calcite, gypsum, or silica.

| rowspan = 12 | ''Fracture trap''; Lateral boundaries of the trap are provided by change from fractured reservoir to unfractured or less fractured rock or by change from open, permeable fractures to cement-filled or narrow-aperture, low-permeability fractures. || rowspan = 4 | ''Extension fracture trap''; Dominant reservoir fractures are extension fractures. || rowspan = 2 | ''Parallel fractures''; Open fractures in a fractured reservoir, predominantly unidirectional in both strike and dip. || ''Mineralized fracture''; Partially or totally mineralized by postfracture cements, typically calcite, [[gypsum]], or silica.

|-

|-

| ''Nonmineralized fracture''; Contains no postfracture cements or minerals.

| ''Nonmineralized fracture''; Contains no postfracture cements or minerals.

| rowspan = 5 | Intersecting || rowspan = 5 | Tectonic fracture trap; Fractures were generated by crustal tectonic stresses, whether compressional, extensional, or transpressional. || rowspan = 2 | Fold-related fracture trap; Fractures are intimately associated with and controlled by tectonic folds. || Related to zone of maximum curvature.

| rowspan = 5 | Intersecting || rowspan = 5 | Tectonic fracture trap; Fractures were generated by crustal tectonic stresses, whether compressional, extensional, or transpressional. || rowspan = 2 | Fold-related fracture trap; Fractures are intimately associated with and controlled by tectonic folds. || Related to zone of maximum curvature.

|-

|-

| Hydrofractures

| [[Natural hydraulic fracturing of top seals|Hydrofractures]]

|-

|-

| rowspan = 2 | Fault-related fracture traps; Fractures are intimately associated with or controlled by tectonic faults. || Fractures related to normal faults

| rowspan = 2 | Fault-related fracture traps; Fractures are intimately associated with or controlled by tectonic faults. || Fractures related to normal faults

|-

|-

| Fractures related to wrench faults

| Fractures related to [http://www.glossary.oilfield.slb.com/en/Terms.aspx?LookIn=term%20name&filter=wrench%20fault wrench faults]

|-

|-

| colspan = 2 | Regional fracture trap; Fractures occur over a broad area unrelated to specific folds or faults and in which fractures are thought to have been created by regional tectonic stresses.

| colspan = 2 | Regional fracture trap; Fractures occur over a broad area unrelated to specific folds or faults and in which fractures are thought to have been created by regional tectonic stresses.

==Nontectonic fracture families==

==Nontectonic fracture families==

A wide variety of nontectonic elements have been interpreted to cause fractures and fracture traps. The more common ones include salt solution, piercement by mobile cores, meteorite impact, compaction drape, shrinkage due to cooling or diagenesis, pore-fluid overpressuring, erosional uplift and unloading, and hydrothermal fracturing. Each of these can be used as nontectonic fracture trap families. Where necessary, subfamilies and varieties can be created for any of these families. The outline below shows the order and some definitions for these traps.

A wide variety of nontectonic elements have been interpreted to cause fractures and fracture traps. The more common ones include salt solution, piercement by mobile cores, meteorite impact, compaction drape, shrinkage due to cooling or [[diagenesis]], pore-fluid overpressuring, erosional uplift and unloading, and hydrothermal fracturing. Each of these can be used as nontectonic fracture trap families. Where necessary, subfamilies and varieties can be created for any of these families. The outline below shows the order and some definitions for these traps.

'''Superclass:''' Extension fractures

:'''Class:''' Intersecting

! Regime || Superclass || Class || Superfamily || Family || Subfamily

::'''Superfamily:''' Nontectonic fracture trap

::Fractures generated by nontectonic stresses, e.g., salt solution, piercement, shrinkage, and overpressuring.

| rowspan = 12 | Fracture || rowspan = 12 | Extension fractures || colspan = 4 | Parallel

:::'''Family:''' Solution collapse

:::'''Family:''' Piercement

| rowspan = 11 | Intersecting || rowspan = 11 | Nontectonic fracture trap; Fractures generated by nontectonic stresses, e.g., salt solution, piercement, shrinkage, and over pressuring. || colspan = 2 | Solution collapse

:::'''Family:''' Impact

:::'''Family:''' Compaction drape

| colspan = 2 | Piercement

:::'''Family:''' Shrinkage

::::'''Subfamily:''' Chert diagenesis

| colspan = 2 | Impact

::::'''Subfamily:''' Cooling joints

:::'''Family:''' Overpressuring

| colspan = 2 | Compaction drape

::::'''Subfamily:''' [[Source rock]] [[maturation]]

::::'''Subfamily:''' Geothermal pressuring

| rowspan = 2 | Shrinkage || [[Chert]] diagenesis

::::'''Subfamily:''' Clay dewatering

:::'''Family:''' Unloading

| Cooling joints

:::'''Family:''' Hydrothermal

| rowspan = 3 | Overpressuring || [[Source rock]] [[maturation]]

| Geothermal pressuring

| Clay dewatering

| colspan = 2 | Unloading

| colspan = 2 | Hydrothermal

==See also==

==See also==

[[Category:Traps, trap types, and the petroleum system]]  

[[Category:Traps, trap types, and the petroleum system]]  

[[Category:Classification of exploration traps]]

[[Category:Classification of exploration traps]]