METHOD OF INVERSE CEMENTING OF CASING COLUMNS Russian patent published in 2019 - IPC E21B33/14 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry and can be used in cementing casing by reverse method in wells of various purposes. According to the method there performed is successive pumping of buffer liquid and grouting mortar into annular space. Grouting mortar is maintained in the annular space for the period of waiting for solidification of the grouting mortar. For this purpose, a buffer liquid containing ferromagnetic filler is used. Magnet is placed inside the casing string. This magnet is moved down the column and retained in annular space with a buffer liquid with ferromagnetic filler and plugging solution placed above the buffer liquid. Note here that annular space is completely filled with backfill solution in mode of plug uniform and gradual displacement of flushing fluid with backfill solution. For this purpose, the injection rate of the grouting mortar and the flushing liquid outlet rate are synchronized by means of a nozzle on the discharge line. Simultaneously, the speed of the magnet moving down in the casing with the ferromagnetic liquid in the annular space is synchronized.

EFFECT: technical result is higher efficiency of reverse cementing.

10 cl, 1 dwg