Modulus—porosity relations, Gassmann’s equations, and the low‐frequency elastic‐wave response to fluids
Modulus—porosity relations, Gassmann’s equations, and the low‐frequency elastic‐wave response to fluids
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DOI：
10.1190/1.1444826
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发表时间：
2000-09
期刊：
影响因子：
3.3
通讯作者：
R. Nolen-Hoeksema
中科院分区：
文献类型：
--
作者：
R. Nolen-Hoeksema
Gassmann方程描述了低频排水和不排水弹性波对流体的响应。本教程探讨了基于Gassmann方程的不同模量-孔隙度关系如何影响流体低频弹性波响应的预测。取不同的模量-孔隙率关系，通过框架模量代入高斯曼方程。结果说明了对流体的响应范围，并可以总结为有效流体系数的nomograph，它量化了孔隙空间模量（∂Kpore/Kpore）响应流体模量（∂Kfluid/Kfluid）的变化。流体模量与固粒模量之比（Kfluid/Ksolid）和Biot系数与孔隙度之比（αK/ φ）是控制有效流体系数的两个比值。有效流体系数图是一种方便的工具，用于估计低频弹性波特性对储层流体变化的响应。
Gassmann’s equations relate the low‐frequency drained and undrained elastic‐wave response to fluids. This tutorial explores how different modulus—porosity relationships affect predictions of the low‐frequency elastic‐wave response to fluids based on Gassmann’s equations. I take different modulus—porosity relations and substitute them into Gassmann’s equations through the framework moduli. The results illustrate the range of responses to fluids and can be summarized in a nomograph of the effective fluid coefficient, which quantifies the change in the pore‐space modulus (∂Kpore/Kpore) in response to a change in fluid modulus (∂Kfluid/Kfluid). Two ratios control the effective fluid coefficient: the ratio of the fluid modulus to the solid‐grain modulus ( Kfluid/Ksolid) and the ratio of the Biot coefficient to porosity (αK/ϕ). The effective fluid coefficient nomograph is a convenient tool for estimating how low‐frequency elastic‐wave properties will respond to changes in reservoir fluids.