METHOD OF CATHODE PROTECTION OF CASING STRINGS OF WELLS AND OIL-FIELD PIPELINES AGAINST CORROSION Russian patent published in 2017 - IPC C23F13/02 

FIELD: oil and gas industry.

SUBSTANCE: method includes drilling a hole to a depth greater than the length of the anode grounding device, drilling the hole in the deepening interval of the anode grounding device into which a cover is set, pumping into the well up to the upper level of the clay solution cover into which the anode grounding electrode is lowered, installing protective current on the casing string through a cathode protection station, measuring common and polarization potentials of protected structures. In case of change of anode grounding electrode device resistance by 20 % and more for restoration of cathode protection of the structure containing 25-30 % clay, 9-12 % gypsum, 0.1-0.2 % salts and sand is the rest. Sulphuric acid and nitrate salts of metals and nitrate are used as salts providing preservation of current conductivity of colmatage solution after filling the hole with up to 60 l of water.

EFFECT: simplified filling of the hole with colmatage solution, reduced loss of solution from the hole into formation, achieved stable protection indicators for the entire period of cathode protection.

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