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- Volume 5, Issue 11, 1987
First Break - Volume 5, Issue 11, 1987
Volume 5, Issue 11, 1987
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Migration and tomography: Radon migration
By H. RuterMigration and tomography are well researched and widely discussed in publications and textbooks. This paper tries to combine both methods by introducing the basic concepts of a new migration technique: Radon migration. This is basically a generalization of Hubral's slant-stack migration (Hubral 1980). In Radon migration one uses well-developed and highly sophisticated tomographic reconstruction techniques to migrate seismie reflection data. Transformation of the seismie wave field to the Radon domain offers specific advantages over standard migration techniques in the time-space or frequency domain, at least in some applications.
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Structure mapping at Trap Spring Oilfield, Nevada, using controlled-source magnetotellurics
Authors L.J. Hughes and N.R. CarlsonThe seismic reflection method has been a highly successful tool in oil and gas exploration for half a century, and it presently accounts for about 98% of all geophysical expenditures world-wide. However, the relatively high cost of seismic exploration and its limitations in certain geologic environments are continuing problems. Some help has been provided by the magnetotelluric (MT) sounding technique, but the cost of MT is also quite high due to the low natural signal strengths being measured. The controlled-source audio-frequency magnetotellurics (CSAMT) technique is a shallower-penetrating variation of MT which uses an artificial signal source. This permits faster and more economical data acquisition. CSAMT has a penetration of about 2 km in typical petroliferous environments. CSAMT does not replace seismic but functions in three specific roles: (1) as a reconnaissance tool to help focus seismic coverage, or to help avoid 'no-record' zones; (2) to assist in statics corrections and in interactive seismic interpretation; (3) as a primary tool in certain environments (volcanics, complex thrust areas) where seismie data acquisition is limited. An example of the application of CSAMT to structure mapping comes from data taken over Trap Spring Field, located in the frontier Great Basin of the western United States. The field produces oil from fractured volcanics at the edge of a major graben fault. The CSAMT data delineate the major subsurface faulting and stratigraphic relationships in the area. The resolution of the CSAMT survey is significantly better than previously obtained induced polarization (IP) data. Detailed comparisons with electric log, drillhole, and air-photo data show an excellent correlation between the CSAMT features and known geology. The work suggests that CSAMT could be used in this area for reconnaissance mapping to develop seismie prospects, at approximately one sixth the cost of seismic.
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Volumes & issues
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Volume 42 (2024)
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Volume 41 (2023)
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Volume 40 (2022)
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Volume 39 (2021)
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Volume 38 (2020)
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Volume 37 (2019)
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Volume 36 (2018)
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Volume 35 (2017)
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Volume 34 (2016)
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Volume 33 (2015)
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Volume 32 (2014)
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Volume 31 (2013)
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Volume 30 (2012)
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Volume 29 (2011)
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Volume 28 (2010)
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Volume 27 (2009)
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Volume 26 (2008)
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Volume 25 (2007)
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Volume 24 (2006)
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Volume 23 (2005)
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Volume 22 (2004)
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Volume 21 (2003)
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Volume 20 (2002)
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Volume 19 (2001)
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Volume 18 (2000)
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Volume 17 (1999)
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Volume 16 (1998)
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Volume 15 (1997)
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Volume 14 (1996)
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Volume 13 (1995)
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Volume 12 (1994)
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Volume 11 (1993)
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Volume 10 (1992)
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Volume 9 (1991)
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Volume 8 (1990)
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Volume 7 (1989)
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Volume 6 (1988)
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Volume 5 (1987)
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Volume 4 (1986)
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Volume 3 (1985)
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Volume 2 (1984)
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Volume 1 (1983)