Changes

==Routine processing techniques==

==Routine processing techniques==

Gravity data as measured must be corrected for the earth's field.<ref name=ch15r2>Chapin, D. A., 1996a, [http://library.seg.org/doi/abs/10.1190/1.1437341 The theory of the Bouguer gravity anomaly: a tutorial]: Leading Edge, May 1996, p. 361–363.</ref> There are five categories of corrections.

[[Gravity]] data as measured must be corrected for the earth's field.<ref name=ch15r2>Chapin, D. A., 1996a, [http://library.seg.org/doi/abs/10.1190/1.1437341 The theory of the Bouguer gravity anomaly: a tutorial]: Leading Edge, May 1996, p. 361–363.</ref> There are five categories of corrections.

{| class = "wikitable"

{| class = "wikitable"

==Interpretive processing techniques==

==Interpretive processing techniques==

After obtaining either free air gravity or [[Wikipedia:Bouguer anomaly|Bouguer]] gravity, subsequent processing may be needed to enhance or suppress various geologic effects. For example, Bouguer gravity naturally has lower values over higher elevations and higher values over deep ocean basins because of variations in the crustal thickness, or ''[http://www.hko.gov.hk/education/edu06nature/ele_isostasy_e.htm isostasy]''. An isostatic correction to suppress this deep effect can be made if the data set is large enough.<ref name=ch15r3>Chapin, D., A., 1996b, A deterministic approach towards computing isostatic gravity residuals: case history from South America: Geophysics, vol. 61, no. 4, p. 1022–1033, DOI: [http://library.seg.org/doi/abs/10.1190/1.1444024 10.1190/1.1444024].</ref> In smaller data sets, typically a long-wavelength surface can be removed from the data to suppress this effect. Other interpretive processing to enhance certain anomalies includes the following:

After obtaining either free air gravity or [[Wikipedia:Bouguer anomaly|Bouguer]] gravity, subsequent processing may be needed to enhance or suppress various geologic effects. For example, Bouguer gravity naturally has lower values over higher elevations and higher values over deep ocean basins because of variations in the crustal thickness, or ''[http://www.hko.gov.hk/education/edu06nature/ele_isostasy_e.htm isostasy]''. An isostatic correction to suppress this deep effect can be made if the data set is large enough.<ref name=ch15r3>Chapin, D. A., 1996b, A deterministic approach towards computing isostatic gravity residuals: case history from South America: Geophysics, vol. 61, no. 4, p. 1022–1033, DOI: [http://library.seg.org/doi/abs/10.1190/1.1444024 10.1190/1.1444024].</ref> In smaller data sets, typically a long-wavelength surface can be removed from the data to suppress this effect. Other interpretive processing to enhance certain anomalies includes the following:

* Band-pass filtering—selecting a range of wavelengths to display

* Band-pass filtering—selecting a range of wavelengths to display

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

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

[[Category:Applying gravity in petroleum exploration]]

[[Category:Applying gravity in petroleum exploration]]