WELL CEMENTING METHOD Russian patent published in 2023 - IPC E21B33/14 

FIELD: oil and gas industry.

SUBSTANCE: invention can be used for cementing casing strings in wells for various purposes. A well cementing method is claimed, which includes pumping cement slurry into the casing string of pipes and pushing it into the annulus, leaving the cup in the pipe string and creating pressure in the annulus when the cement slurry solidifies. At the same time, the maximum allowable pressure values for each of the layers and the intervals of their location are determined from the cores selected during drilling, the permissible average density of the cement slurry and the intervals of the location of the productive formation are determined. Then buffer fluid and cement slurry are successively pumped into the casing string and the buffer fluid and the cement slurry are displaced into the annulus by the displacement fluid. The grouting slurry is pumped in portions: the first portion of the medium-density cement slurry is pumped into the interval from the roof of the productive horizon to the wellhead, the second portion of the weighted cement slurry is pumped into the interval from the bottomhole to the interval providing the overlap of the productive formation. In the process of pumping the squeezing fluid 10-50 m before the completion of the squeezing process of the estimated volume of the squeezing fluid, the squeezing process is stopped for a time before the cement slurry begins to thicken, then the squeezing is resumed at the maximum allowable pressures for the casing string and well wall rocks and the remaining volume is squeezed by the squeezing fluid until the STOP pressure is achieved.

EFFECT: creating a zone of reliable isolation of the operated target in the cemented interval due to the controlled process of preparation and injection of solutions, and the exclusion of hydraulic fracturing.

2 cl