An analysis of casing pressure causes in oil wells at the fields of Tyumen region

The article deals with the issues of qualitative isolation of reservoirs, which are saturated with water or hydrocarbons. The conducted scientific research substantiated the method of ranking wells with casing pressure, according to which wells are assigned to one or another hazard group depending on the ratio of the casing pressure to the pressure of surface pipe as a screening column. The studies have shown that the decrease in the hydrostatic column of cement slurry occurs in the process of thickening due to the "hanging" of the slurry on the walls of the well because of the appearance of a structural frame in it. At the same time, the intensity of depressurization of the cement ring increases, and various kinds of channels make appearance, in which the reservoir fluid subsequently moves through the annular space. We propose an algorithm of preparatory measures aimed at determining priority actions in the process of eliminating casing pressure.