Appeal No. 97-1628
Application No. 08/442,610
typically, the casing is referred to as the first material,
and an interface is formed between it and the second material,
which is the cement that surrounds the casing. A third
interface exists between the cement and the earth surrounding
the borehole. Imperfect conditions, however, can cause other
interfaces to be present, such as at voids in the cement
(specification, page 2; Figure 1). The appellants admit that
is has been known to utilize acoustic methods and apparatus to
interrogate a cased borehole environment. However, the
invention utilizes a system in which only “shear acoustic
energy” is utilized beyond the casing. In this regard, we
understand that there are two forms of acoustic energy that
figure in this case. They are “shear” acoustic energy, in
which the particle motion in the acoustic waves is
perpendicular to the direction of wave travel, and
“compressional” acoustic energy, in which the particle motion
is in the direction of wave travel (see Vogel, column 1, lines
31-36).
All of the claims have been grouped together in the
rejection. According to the examiner, in the Broding system
shear energy propagated within the casing is reflected at the
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