BUFFER MIXTURE USED IN CEMENTING CASING STRINGS IN CONDITIONS OF SALINE DEPOSITS Russian patent published in 2025 - IPC C09K8/40 

FIELD: well construction.

SUBSTANCE: invention relates to the field of well construction, namely to spacer fluids used in cementing casing strings in oil, gas and gas condensate wells. Buffer mixture used in cementing casing strings of wells in conditions of saline deposits contains the following, wt. %: magnesia-silica additive – heat treated at temperature of 1020-1050 °C serpentinite-containing rock, crushed to specific surface area of 300-320 m²/kg, 48.2-57; water-reducing additive – technical lignosulphonate 0.9-1.5; complexing agent – sodium gluconate 0.1-0.3; highly mineralized water based on NaCl with density of 1180-1200 kg/m³ 42-50.

EFFECT: preventing mixing of drilling and grouting solutions, cleaning walls of wells and columns, increasing completeness of replacement of flushing fluid with grouting solution in conditions of salt-bearing deposits containing magnesian salts, abnormal formation pressure and temperature of 50-100 °C.

1 cl, 2 tbl