Elastic-wave velocity in marine sediments with gas hydrates: Effective medium modeling

被引：505

作者：

Helgerud, MB ^{[1
]}

Dvorkin, J

Nur, A

Sakai, A

Collett, T

机构：

[1] Stanford Univ, Dept Geophys, Stanford, CA 94305 USA

[2] Japan Petr Explorat Co Ltd, Shinagawa Ku, Tokyo 140, Japan

[3] US Geol Survey, Denver Fed Ctr, Denver, CO 80225 USA

来源：

GEOPHYSICAL RESEARCH LETTERS | 1999年 / 26卷 / 13期

关键词：

D O I：

10.1029/1999GL900421

中图分类号：

P [天文学、地球科学];

学科分类号：

07 ;

摘要：

We offer a first-principle-based effective medium model for elastic-wave velocity in unconsolidated, high porosity, ocean bottom sediments containing gas hydrate. The dry sediment frame elastic constants depend on porosity, elastic moduli of the solid phase, and effective pressure. Elastic moduli of saturated sediment are calculated from those of the dry frame using Gassmann's equation. To model the effect of gas hydrate on sediment elastic moduli we use two separate assumptions: (a) hydrate modifies the pore fluid elastic properties without affecting the Framer (b) hydrate becomes a component of the solid phase, modifying the elasticity of the frame. The goal of the modeling is to predict the amount of hydrate in sediments from sonic or seismic velocity data. We apply the model to sonic and VSP data From ODP Hole 995 and obtain hydrate concentration estimates from assumption (b) consistent with estimates obtained from resistivity, chlorinity and evolved gas data.

引用

页码：2021 / 2024

页数：4