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Magnetotelluric survey case history: volcanic terrain (Columbia River Plateau) (view source)
Revision as of 23:09, 17 January 2014
, 23:09, 17 January 2014Initial import
{{publication
| image = exploring-for-oil-and-gas-traps.png
| width = 120px
| series = Treatise in Petroleum Geology
| title = Exploring for Oil and Gas Traps
| part = Predicting the occurrence of oil and gas traps
| chapter = Applying magnetotellurics
| frompg = 16-1
| topg = 16-12
| author = Arnie Ostrander
| link = http://archives.datapages.com/data/specpubs/beaumont/ch16/ch16.htm
| pdf =
| store = http://store.aapg.org/detail.aspx?id=545
| isbn = 0-89181-602-X
}}
Seismic methods do not work well in areas covered by volcanics because of the dispersive nature of the volcanics and because of the decrease in acoustic velocity at the base of the volcanics.
Volcanic terrain, however, is an ideal environment for MT because it is a simple, three-layer stratigraphic package: resistive basalts over conductive sediments, which in turn overlie resistive metamorphic or granitic basement rocks.
==Survey results==
The cross section below is a 13-station MT natural source survey profile. This east-west section begins near the Idaho-Washington border and extends approximately [[length::75 mi]] (120 km) to the west (Mills, personal communication, 1994).
[[file:applying-magnetotellurics_fig16-8.png|thumb|{{figure number|16-8}}Drafted from data from .<ref name=ch16r5>Mills, A., 1994, Zephyr Geophysical Services, personal communication.</ref>]]
==Structural details==
These data provided the following structural details:
* Considerable variation on the thickness of the volcanics
* Considerable variation in the depth to top of basement
* Basalts thin to the east
* Sediments thin to east and eventually disappear
* Basement resistivities are an order-of-magnitude higher on the east end of the profile
Controlled-source MT data could provide 3-D imaging of individual prospects.
==See also==
* [[Overview]]
* [[What is Magnetotellurics (MT)?]]
* [[What does an MT survey measure?]]
* [[How are MT data acquired?]]
* [[Case history: frontier basin analysis (Amazon Basin, Colombia)]]
* [[Case history: rugged carbonate terrain (Highlands of Papua New Guinea)]]
* [[Case history: Precambrian overthrust (Northwestern Colorado)]]
==References==
{{reflist}}
==External links==
{{search}}
* [http://archives.datapages.com/data/specpubs/beaumont/ch16/ch16.htm Original content in Datapages]
* [http://store.aapg.org/detail.aspx?id=545 Find the book in the AAPG Store]
[[Category:Predicting the occurrence of oil and gas traps]]
[[Category:Applying magnetotellurics]]
| image = exploring-for-oil-and-gas-traps.png
| width = 120px
| series = Treatise in Petroleum Geology
| title = Exploring for Oil and Gas Traps
| part = Predicting the occurrence of oil and gas traps
| chapter = Applying magnetotellurics
| frompg = 16-1
| topg = 16-12
| author = Arnie Ostrander
| link = http://archives.datapages.com/data/specpubs/beaumont/ch16/ch16.htm
| pdf =
| store = http://store.aapg.org/detail.aspx?id=545
| isbn = 0-89181-602-X
}}
Seismic methods do not work well in areas covered by volcanics because of the dispersive nature of the volcanics and because of the decrease in acoustic velocity at the base of the volcanics.
Volcanic terrain, however, is an ideal environment for MT because it is a simple, three-layer stratigraphic package: resistive basalts over conductive sediments, which in turn overlie resistive metamorphic or granitic basement rocks.
==Survey results==
The cross section below is a 13-station MT natural source survey profile. This east-west section begins near the Idaho-Washington border and extends approximately [[length::75 mi]] (120 km) to the west (Mills, personal communication, 1994).
[[file:applying-magnetotellurics_fig16-8.png|thumb|{{figure number|16-8}}Drafted from data from .<ref name=ch16r5>Mills, A., 1994, Zephyr Geophysical Services, personal communication.</ref>]]
==Structural details==
These data provided the following structural details:
* Considerable variation on the thickness of the volcanics
* Considerable variation in the depth to top of basement
* Basalts thin to the east
* Sediments thin to east and eventually disappear
* Basement resistivities are an order-of-magnitude higher on the east end of the profile
Controlled-source MT data could provide 3-D imaging of individual prospects.
==See also==
* [[Overview]]
* [[What is Magnetotellurics (MT)?]]
* [[What does an MT survey measure?]]
* [[How are MT data acquired?]]
* [[Case history: frontier basin analysis (Amazon Basin, Colombia)]]
* [[Case history: rugged carbonate terrain (Highlands of Papua New Guinea)]]
* [[Case history: Precambrian overthrust (Northwestern Colorado)]]
==References==
{{reflist}}
==External links==
{{search}}
* [http://archives.datapages.com/data/specpubs/beaumont/ch16/ch16.htm Original content in Datapages]
* [http://store.aapg.org/detail.aspx?id=545 Find the book in the AAPG Store]
[[Category:Predicting the occurrence of oil and gas traps]]
[[Category:Applying magnetotellurics]]