Changes

{{publication  

{{publication  

  | image  = exploring-for-oil-and-gas-traps.png

  | image  = exploring-for-oil-and-gas-traps.png

  | part    = Critical elements of the petroleum system

  | part    = Critical elements of the petroleum system

  | chapter = Formation fluid pressure and its application

  | chapter = Formation fluid pressure and its application

  | frompg  = 5-1

  | frompg  = 5-8

  | topg    = 5-64

  | topg    = 5-8

  | author  = Edward A. Beaumont, Forrest Fiedler

  | author  = Edward A. Beaumont, Forrest Fiedler

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch05/ch05.htm

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch05/ch05.htm

  | isbn    = 0-89181-602-X

  | isbn    = 0-89181-602-X

}}

}}

Abnormal hydrostatic pressure is a departure from normal fluid pressure that is caused by geologic factors. The term “[http://www.glossary.oilfield.slb.com/en/Terms/g/geopressure.aspx geopressure]” was introduced originally by Shell Oil Company to refer to overpressured intervals in the U.S. Gulf Coast. “Geopressure” is gradually being replaced by the more descriptive terms “[http://en.wikipedia.org/wiki/Geologic_overpressure overpressure]” and “[http://www.glossary.oilfield.slb.com/en/Terms/u/underpressure.aspx underpressure].”

 

Abnormal hydrostatic pressure is a departure from normal fluid pressure that is caused by geologic factors. The term “[[geopressure]]” was introduced originally by Shell Oil Company to refer to overpressured intervals in the U.S. Gulf Coast. “Geopressure” is gradually being replaced by the more descriptive terms “[[overpressure]]” and “[[underpressure]].”

==Causes==

==Causes==

Abnormal fluid pressures may be caused by any of the following:

Abnormal fluid pressures may be caused by any of the following:

* Uplift

* [[Uplift]]

* Burial

* [[Burial]]

* Rock compaction or dilation

* [[Reservoir_quality#Compaction|Rock compaction]] or [[Rock dilation|dilation]]

* Abnormal heat flow

* Abnormal [[heat flow]]

Abnormal pressures develop when fluid is unable to move into or out of the local pore system fast enough to accommodate to the new environment. Such a pore system must be isolated from the surrounding system by impermeable barriers for abnormal pressure to exist.

Abnormal pressures develop when fluid is unable to move into or out of the local [[Pore system fundamentals|pore system]] fast enough to accommodate to the new environment. Such a pore system must be isolated from the surrounding system by [[Wikipedia:Permeability (earth sciences)|impermeable]] barriers for abnormal pressure to exist.

The table below shows the generally accepted major causes of abnormal fluid pressure.

The table below shows the generally accepted major causes of abnormal fluid pressure.

{| class = "wikitable"

{| class = "wikitable"

|-

|-

! Overpressure

! Overpressure || Underpressure

! Underpressure

|-

|-

| Uplift

| Uplift || Burial

| Burial

|-

|-

| Heat increase

| Heat increase || Heat decrease

| Heat decrease

|-

|-

| Compaction Generation of hydrocarbons

| [[Reservoir_quality#Compaction|Compaction]],  [[Petroleum generation|Generation of hydrocarbons]] || Dilation of pores

| Dilation of pores

|}

|}

==See also==

==See also==

* [[Normal hydrostatic pressure]]

* [[Normal hydrostatic pressure]]

* [[Geostatic and lithostatic pressure]]

* [[Geostatic and lithostatic pressure]]

[[Category:Critical elements of the petroleum system]]  

[[Category:Critical elements of the petroleum system]]  

[[Category:Formation fluid pressure and its application]]

[[Category:Formation fluid pressure and its application]]