The paper deals with the development of sounders for surveying vertical shafts filled with drilling mud. The experience of implementation of sonic borescope surveying is given.

In the process of drilling and fixing technical wells of large diameter (1.0-3.6 m) there are a number of technical problems, the solution of which is possible if the geometry and dimensions of the borehole (curvature of the axis, the size of the wall development, etc.), as well as the position of the support during its construction are known. Wells are drilled vertically up to 1000 m deep. Drilling is carried out with the use of flushing fluid, as which is used clay solution with a specific gravity of up to 1.25 g/cm2 depending on the strength of the rock...