Porosity and consolidation limits of sediments and Gassmann's Elastic‐Wave Equation
1993; American Geophysical Union; Volume: 20; Issue: 9 Linguagem: Inglês
10.1029/93gl00863
ISSN1944-8007
Autores Tópico(s)Seismic Imaging and Inversion Techniques
ResumoThe elastic framework properties of sediments relate to porosity. Porosity relates to the state of consolidation of sediments. The full range of quasi‐static, elastic moduli vs porosity behavior can be incorporated into Gassmann's [1951] equations. I review the Atterberg [1911] limits to establish a basis for discussing the precompaction porosity, ф 0 , which corresponds approximately to the Atterberg plastic limit. This porosity is about 0.36–0.40 for sands and sandstones. The ratio of the dry‐frame moduli to the effective mineral moduli is (1−ф/ф 0 ). I incorporate this ratio into Gassmann's equations, which operate from 0 ≤ ф ≤ ф 0 , when sediments have a solid elastic frame. For ф s> ф 0 , when sediments no longer have a solid elastic frame, Gassmann's equations reduce to Reuss' [1929] isostress average for the solid‐fluid mixture.
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