Changes

  | part    = Predicting the occurrence of oil and gas traps

  | part    = Predicting the occurrence of oil and gas traps

  | chapter = Applying magnetotellurics

  | chapter = Applying magnetotellurics

  | frompg  = 16-1

  | frompg  = 16-9

  | topg    = 16-12

  | topg    = 16-9

  | author  = Arnie Ostrander

  | author  = Arnie Ostrander

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch16/ch16.htm

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch16/ch16.htm

  | isbn    = 0-89181-602-X

  | isbn    = 0-89181-602-X

}}

}}

The Papuan thrust belt is both an expensive and difficult area in which to acquire seismic data. The area is typified by rugged mountainous terrain, dense equatorial jungle, and thick, heavily karstified limestone. The karstified limestone in some areas is also overlain by heterogeneous volcanics. The few coherent seismic reflectors are lacking in character and continuity, and the data in general are extremely noisy.

The Papuan [[thrust belt]] is both an expensive and difficult area in which to acquire [[seismic data]]. The area is typified by rugged mountainous terrain, dense equatorial jungle, and thick, heavily [[karst]]ified [[limestone]]. The karstified limestone in some areas is also overlain by heterogeneous [[Wikipedia:Volcanic_rock|volcanics]]. The few coherent seismic reflectors are lacking in character and continuity, and the data in general are extremely noisy.

The sedimentary section in this area, however, is an excellent MT target.<ref name=ch16r1>Billings, A., J., Thomas, J., H., 1990, The use and limitations of non-seismic geophysics in the Papuan thrust belt, in Carman, C., J., Carman, Z., eds., Proceedings of the First PNG Petroleum Convention: Port Moresby, New Guinea, p. 51–62.</ref> This sequence observed in MT data is a simple three-layer package. The upper layer is the high-resistivity Darai Limestone, the middle layer is low-resistivity Leru Formation clastics, and the third layer is high-resistivity basement rocks. Therefore, the MT data provide a subsurface map of the base of the Darai and the top of the basement. The addition of an upper high-resistivity volcanic layer in some areas usually does not complicate this interpretation, except that it may not be possible to differentiate the base of the volcanics from the top of the Darai.

The sedimentary section in this area, however, is an excellent [[Magnetotellurics|magnetotelluric]] (MT) target.<ref name=ch16r1>Billings, A. J., and J. H. Thomas, 1990, The use and limitations of non-seismic geophysics in the Papuan thrust belt, in C. J. Carman, and Z. Carman, eds., Proceedings of the First PNG Petroleum Convention: Port Moresby, New Guinea, p. 51–62.</ref> This sequence observed in MT data is a simple three-layer package. The upper layer is the high-resistivity Darai Limestone, the middle layer is low-resistivity Leru Formation clastics, and the third layer is high-resistivity [[basement]] rocks. Therefore, the MT data provide a subsurface map of the base of the Darai and the top of the basement. The addition of an upper high-resistivity volcanic layer in some areas usually does not complicate this interpretation, except that it may not be possible to differentiate the base of the volcanics from the top of the Darai.

==Survey results==

==Survey results==

* [[Magnetotelluric data acquisition]]

* [[Magnetotelluric data acquisition]]

* [[Magnetotellurics case history: frontier basin analysis (Amazon Basin, Colombia)]]

* [[Magnetotellurics case history: frontier basin analysis (Amazon Basin, Colombia)]]

* [[Case history: Precambrian overthrust (Northwestern Colorado)]]

* [[Magnetotellurics case history: Precambrian overthrust (Northwestern Colorado)]]

* [[Case history: volcanic terrain (Columbia River Plateau)]]

* [[Magnetotellurics case history: volcanic terrain (Columbia River Plateau)]]

==References==

==References==

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

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

[[Category:Applying magnetotellurics]]

[[Category:Applying magnetotellurics]]