Estimation of the capacity of the channel (gap) between a boring casing and the cement stone, arising at casing pressure testing

The causes of infringement of contact of a cement stone with boring casings are analysed. The question of determination of size of the clearance, arising in ring space at casing pressure testing, is considered. It is offered at estimation of the wells cementing quality with the method of cement-bond sonic logging to accept the limiting clearance size equal to 100 microns.