METHOD OF CEMENTATION TOP STAGE OF CASING PIPE IN WELL Russian patent published in 2010 - IPC E21B33/14 

FIELD: oil-and-gas production.

SUBSTANCE: it includes pumping in of calculated volume of grouting mortar inside the casing string after waiting of cement congelation of the first stage and its punching through its side cementing ports in casing string-borehole annulue by squeezing liquid. Before grouting mortar it is pumped in displacement fluid and displacement fluid is pumped in by portions. In the capacity of the first portion it is used abrasive-carrying cement mortar of increased density, and in the capacity of the second portion - cement mortar of standard density. After punching of them into casing string-borehole annulue up to receiving of pressure "stop" abrasive-carrying cement mortar subject to repeated alternate motion by means of takeoff inside the casing of part of grouting mortar and it is continued punching up to receiving of pressure "stop". Additionally to alternate motion mortar is subject to in several stages during the period of cementation.

EFFECT: effective destruction of adhesive film in casing string-borehole annulue and maximal removing of residues of drilling mud in well, also it increases quality of formation isolation and increases strength of contact of casing cement stone with environment.

4 cl, 1 tbl