Abstract
Abstract Features of colmatation zones of a productive formation in terms of rotary drilling by drilling muds are considered. A brief analysis of the most popular decolmatation methods is performed. Special attention is paid to the decolmatation method involving implosion effect. An example of one of the existing installations is represented with following consideration of its application features. A new principally different installation, free from the disadvantages found in the available one, is considered; a patent for the installation is obtained in Kazakhstan. It does not involve tubing with its packer and wellhead sealing. It also does not require a compressor and its manifold. Characteristic features of the newly developed installation for creating implosion effect are represented; its operation at producing both single and any number of repeated implosion acts is examined. A mathematical analysis is performed to calculate the empty space limits required for the implosion effect by a criterion to prevent casing string collapse by hydrostatic pressure of the drilling mud remained in the annular space. An example of dependency of the maximum permitted length of empty space in the casing string on its mechanical strength and its wall thickness, calculated by means of a computer program, is represented.