WELL CLAY CAKE REMOVAL METHOD AND REDUCTION OF FILTRATION RESISTANCE IN BOTTOM-HOLE FORMATION ZONE Russian patent published in 2025 - IPC E21B43/27 C09K8/528 

FIELD: mining.

SUBSTANCE: invention relates to oil industry, particularly to methods of increasing permeability of clay-containing terrigenous and carbonate reservoirs, methods of elimination of differential sticking during well drilling and clay cake removal of bottom-hole formation zone after well drilling before their development. In the well clay cake removal method and the filtration resistances reduction in the formation bottom-hole zone, including the clay cake removal solution injection, as said injected clay cake removal solution, an aqueous solution is used, which contains maleic acid, sodium carbonate, hydrogen peroxide and acetic acid, obtained from an aqueous solution of sodium percarbonate and maleic anhydride, as a result of the dissolution of which maleic acid and sodium carbonate solution with hydrogen peroxide are formed, to which a solution of acetic acid is added with a weight ratio of sodium percarbonate : maleic anhydride : acetic acid 1:1:2.4. After injection of the above clay cake removal solution there performed is a waiting period for dispersion of clay deposits in the well shaft or bottom-hole zone of formation for 2 hours; after that, development is performed with removal of dispersed clay together with process liquid or well product.

EFFECT: destruction of structure of clay deposits with formation of highly mobile fine clay particles in water medium, which are carried to the surface together with process liquid or product of the well.

1 cl, 7 dwg