1964 Paper K

A THEORETICAL ANALYSIS OF WAVE PROPAGATION IN FLUID FILLED DRILL HOLES FOR THE INTERPRETATION OF THE 3 DIMENSIONAL VELOCITY LOG

Dean M. Christensen

Birdwell, a Division of Seismograph Service Corporation Tulsa, Oklahoma

ABSTRACT

Considerable attention has recently been directed to the application of composite recording of acoustic energy propagated in and along the boundaries of fluid filled boreholes. A significant feature of one particular logging system is that sufficient data is available for analysis on the basis of theoretical wave mechanics. The main interest has been centered around its use in defining physical properties of the earth.

In this paper, a theoretical analysis is presented to show that two distinct mechanisms of wave interaction at the boundaries of a liquid-solid system will produce complimentary but complex energy propagation in and along the solid boundary. It is shown, that by considering these mechanisms together with the stress-strain state at the boundary: interpretation of these records can be significantly enhanced when attempting to define the physical properties of an aggregate solid.

A general method for interpretation of records is presented, the format having been developed from evaluation of records acquired from 75 surveys in a variety of rock structure. It is suggested that data acquired from the logs permits calculation of porosity, Poisson's ratio, density and the elastic properties of the earth without prior knowledge about lithology being investigated.