Publikationsdatum:
2011-05-24
Beschreibung:
ABSTRACT The relationship between V p and V s may be used to predict V s where only V p is known. V p /V s is also used to identify pore fluids from seismic data and amplitude variation with offset analysis. Theoretical, physical, as well as statistical empirical V p -V s relationships have been proposed for reservoir characterization when shear-wave data are not available. In published work, the focus is primarily on the V p -V s relationship of quartzitic sandstone. In order to broaden the picture we present V p -V s relationships of greensand composed of quartz and glauconite by using data from the Paleocene greensand Nini oil field in the North Sea. A V p -V s relationship derived from modelling is compared with empirical V p -V s regressions from laboratory data as well as from log data. The accuracy of V s prediction is quantified in terms of root-mean-square error. We find that the V p -V s relationship derived from modelling works well for greensand shear-wave velocity prediction. We model the seismic response of glauconitic greensand by using laboratory data from the Nini field. Our studies here reveal that brine-saturated glauconitic greensand can have a similar seismic response to that from oil-saturated quartzitic sandstone and that oil-saturated strongly cemented greensand can have a similar amplitude variation with offset response to that from brine-saturated weakly cemented greensand.
Print ISSN:
0016-8025
Digitale ISSN:
1365-2478
Thema:
Geologie und Paläontologie
,
Physik
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