LIGHT-WEIGHT GROUTING MIXTURE Russian patent published in 2018 - IPC C09K8/42 E21B33/138 

FIELD: oil and gas industry.

SUBSTANCE: invention can be used in a single-stage cementing of long casing strings (more than 2500 m) overlapping the intervals of permeable layers and layers with low gradient of hydraulic fracturing under normal, moderate and elevated temperatures. In the following components the grouting mixture includes, wt %: grouting portland cement - 47.83-48.77, HPP fly ash - 44.94-47.80, micro-silica MK-85 or MK-65 0.96-2.93, structure-forming regulator-hydroxyethylcellulose natrosol 250 - 0.29-0.49, nitrilotrimethylphosphonic acid NTFA 0.01-0.02, sodium chloride 1.95-3.83.

EFFECT: highly efficient cementing of long casing strings in one stage at normal and moderate temperatures providing required thickening time for safe completion of cementing works.

1 tbl, 1 ex