METHOD FOR MUDDED RESERVOIR TREATMENT Russian patent published in 2007 - IPC E21B43/22 E21B43/27 C09K8/72 

FIELD: oil production, particularly to increase oil reservoir productivity and intake capacity of injection well by mud removal from well bottom zone of terrigenous clay reservoir having low permeability and/or from bottom of well characterized by decreased output resulted from pore mudding with clay material.

SUBSTANCE: method involves injecting aqueous hydrochloric acid solution; supplying aqueous surfactant solution; injecting aqueous oxygen-containing agent solution and performing time delay; supplying aqueous surfactant solution; injecting aqueous hydrochloric acid solution; executing time delay and developing well. Aqueous hydrochloric acid solution includes inhibited hydrochloric acid taken in amount of 4-12 % by weight, hydrofluoric acid in amount of 0.01-4% by weight, acetic acid in amount of 0.1-4% by weight, surfactant, namely oxyethylated monoalkylphenols based on propylene terpolymer in amount of 0.05-4% by weight, remainder is water. Volume of aqueous hydrochloric acid solution is equal to 0.1-3 m³ per 1 m of perforated productive reservoir thickness. The aqueous surfactant solution includes 0.1-3% by weight of surfactant and water and is taken in amount of 0.2-1 m³ per 1 m of perforated productive reservoir thickness. Aqueous oxygen-containing agent solution is 5-12% aqueous sodium carbonate perhydrate solution or 5-12% aqueous sodium borate perhydrate solution or 5-15% aqueous carbamide perhydrate solution or 3-10% aqueous hydrogen peroxide solution or 5-20% aqueous sodium hypocloride or 5-20% aqueous potassium hypocloride solution and is taken in amount of 0.1-3 m³ per 1 m of perforated productive reservoir thickness. Aqueous oxygen-containing agent solution may additionally include surfactant, namely oxyethylated monoalkylphenols based on propylene terpolymer in amount of 0.05-4% by weight. Time delay is carried out for not more than 8 hours.

EFFECT: increased treatment efficiency, increased well bottom zone permeability and well productivity.

3 cl, 1 tbl