Predicting seismic velocity and other rock properties from clay content only

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doi: 10.1190/1.1635037
Author(s): Pratson, Lincoln F.; Stroujkova, Anastasia; Herrick, Damian; Boadu, Fred; Malin, Peter
Author Affiliation(s): Primary:
Duke University, Department of Earth and Ocean Sciences, Durham, NC, United States
University of Connecticut, United States
Volume Title: Geophysics
Source: Geophysics, 68(6), p.1847-1856. Publisher: Society of Exploration Geophysicists, Tulsa, OK, United States. ISSN: 0016-8033 CODEN: GPYSA7
Note: In English. 32 refs.; illus., incl. 1 table
Summary: It has been shown that accurate predictions of compressional and shear-wave velocities can be derived from measurements of clay content, porosity, and bulk density. In this paper, we test the efficacy of using a sequence of established petrophysical formulations to go a step further and predict porosity and bulk density as well as velocity from clay content alone. Other variables, like grain and pore-fluid properties, are assumed to be constant, while empirical relationships are used to model such behaviors as grain packing and compaction. The sequence of formulations, referred to as the "model," is evaluated using well-log and core data from the Amazon Fan collected during Ocean Drilling Program Leg 155. Clay contents are estimated from the borehole gamma-ray logs. These are input to the model, which in turn predicts observed porosities to a rms error of <20%, and bulk densities and compressional velocities to rms errors of <-10%. The results suggest that with better measurements of clay content and improvements to the model, even more accurate predictions of velocity might be achieved for unconsolidated sediments.
Year of Publication: 2003
Research Program: ODP Ocean Drilling Program
Key Words: 20 Geophysics, Applied; 30 Engineering Geology; Algorithms; Amazon Fan; Atlantic Ocean; Body waves; Clay minerals; Elastic waves; Equatorial Atlantic; Gamma-ray methods; Geophysical methods; Geophysical surveys; Leg 155; North Atlantic; ODP Site 931; ODP Site 936; ODP Site 940; ODP Site 944; ODP Site 946; Ocean Drilling Program; P-waves; Physical properties; Porosity; Rock mechanics; Seismic methods; Seismic waves; Sheet silicates; Silicates; Surveys; Turbidite; Well-logging
Coordinates: N065658 N065658 W0475510 W0475510
N055622 N055622 W0474526 W0474526
N053756 N053756 W0474408 W0474408
Record ID: 2005018578
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