Expressions that relate velocity to porosity and to pore-fluid compressibility are among the most important deliverables of rock physics. Such relations are used often as additional controls for inferring porosity from well logs, as well as in-situ indicators of pore fluid type. The oldest and most popular is the Wyllie et al. (1956) equation:  
where tP is the measured traveltime of a P-wave, τS is the traveltime expected in the solid-phase material, andτF is the traveltime expected in the pore fluid. It follows from equation (1) that  
where ϕ is porosity, Vp is the measured P-wave velocity, and VpS and VpF are the P-wave velocities in the solid and in the pore-fluid phases, respectively.
This content is PDF only. Please click on the PDF icon to access.

First Page Preview

First page PDF preview
You do not currently have access to this article.