  A numerical method is proposed for carrying out a full-scale simulation of
the process of propagation of an acoustic signal in a cased well. The main goal
is to study the interaction of the wave field with the vertical boundary of the
cement filling the annular and near-pipe space. Particular attention is paid to
the analysis of the intensity of the wave reflected from this boundary,
depending on the degree of hardening of the upper edge of the cement.
  A distinctive feature of the problem is the presence in it of several
significantly different spatial scales. So, the length of the well can vary
from several hundred meters to several kilometers, the diameter of the well is
a few tens of centimeters, and the thickness of the casing string, as a rule,
does not exceed a few first centimeters. It is this diversity of scale that
requires the organization of parallel computing, the organization of which is
based on the spatial decomposition of the region and the involvement of Message
Passing Interface (MPI). The results of test calculations are presented and an
analysis of the strong and weak scalability of the developed software is
carried out.
