Changes

  | part    = Predicting the occurrence of oil and gas traps

  | part    = Predicting the occurrence of oil and gas traps

  | chapter = Value of geological fieldwork

  | chapter = Value of geological fieldwork

  | frompg  = 19-1

  | frompg  = 19-37

  | topg    = 19-42

  | topg    = 19-37

  | author  = Denise M. Stone

  | author  = Denise M. Stone

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch19/ch19.htm

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch19/ch19.htm

  | isbn    = 0-89181-602-X

  | isbn    = 0-89181-602-X

}}

}}

==Magellans and GPS positioning==

==Global positioning system positioning==

Magellans and GPS positioning devices offer a handy way to find your location with respect to surface maps. [[Wikipedia:Latitude|Latitude]] and [[Wikipedia:Longitude|longitude]] coordinates are read from a lightweight, hand-held device that determines position by triangulating with functioning satellites overhead. Coordinates are particularly useful when making numerous road stops and can be input into a computer for plotting.

[[Wikipedia:Global Positioning System|Global positioning system]] (GPS)  devices offer a handy way to find your location with respect to surface maps. [[Wikipedia:Latitude|Latitude]] and [[Wikipedia:Longitude|longitude]] coordinates are read from a lightweight, hand-held device that determines position by triangulating with satellites overhead. Coordinates are particularly useful when making numerous road stops and can be input into a computer for plotting.

==Outcrop [[Basic open hole tools#Gamma ray|gamma-ray]] logging==

==Outcrop gamma-ray logging==

Outcrop gamma-ray logging can be a valuable technique for stratigraphic correlation. It allows a quantitative tie between surface and subsurface using a measurement common to both: the gamma-ray curve. This kind of tie can be more credible than “jump correlating” (identifying events on noncontiguous seismic records or lithologic horizons on well logs, separated by distance, as the same or correlative interfaces in the earth), particularly when significant distance is involved.

[http://www.merriam-webster.com/dictionary/outcrop Outcrop] gamma-ray logging can be a valuable technique for stratigraphic correlation. It allows a quantitative tie between surface and subsurface using a measurement common to both: the gamma-ray curve. This kind of tie can be more credible than “jump correlating” (identifying events on noncontiguous seismic records or lithologic horizons on well logs, separated by distance, as the same or correlative interfaces in the earth), particularly when significant distance is involved.

Two methods of outcrop gamma-ray logging are currently in use:

Two methods of outcrop gamma-ray logging are currently in use:

* Hand-held scintillometer

* Hand-held scintillometer

These tools measure the surface gamma radiation signature emitted by sedimentary outcrops. The data collected can be used to compare and correlate to subsurface sedimentary sections whose radiation signature is measurable only with sophisticated downhole wireline logging tools. Gamma radiation is the most commonly used data set to correlate stratigraphy laterally.

These tools measure the surface gamma radiation signature emitted by sedimentary outcrops. The data collected can be used to compare and correlate to subsurface sedimentary sections whose radiation signature is measurable only with sophisticated downhole wireline logging tools. (See [[Basic open  hole tools]].) Gamma radiation is the most commonly used data set to correlate stratigraphy laterally.

==Shallow coring==

==Shallow coring==

Surface outcrop samples of a given formation are assumed to be the best available example of that same formation at depth. If this isn't the case, though, another approach exists. A shallow coring program is a cost-effective way to obtain surface geologic data in areas of limited outcrops, severe surface weathering, thick vegetation, and/or thin alluvial cover. A seismic shot hole or water well drilling rig can be strategically positioned for collecting such samples.

Surface [http://www.merriam-webster.com/dictionary/outcrop outcrop] samples of a given formation are assumed to be the best available example of that same formation at depth. If this isn't the case, though, another approach exists. A shallow coring program is a cost-effective way to obtain surface geologic data in areas of limited outcrops, severe surface weathering, thick vegetation, and/or thin [[alluvial]] cover. A seismic shot hole or water well drilling rig can be strategically positioned for collecting such samples.

 

==External links==

==External links==

[[Category:Predicting the occurrence of oil and gas traps]]  

[[Category:Predicting the occurrence of oil and gas traps]]  

[[Category:Value of geological fieldwork]]

[[Category:Value of geological fieldwork]]