On the bases of specions experimental investigations it was ascertained that the loading condition, i.e. the rate of axial force is a characterising pecularity of the fit process of elastic element of packer. It is to be noted that these factores have been studied for the first time. it was proved that with the purpouse of reducing the self-packing axial force for improving the sealing capacity of elastic element it is required to apply a force with should be different rates.