METHOD OF INSULATING WASHED HIGH-PERMEABILITY ZONES OF PRODUCTIVE FORMATION Russian patent published in 1999 - IPC

FIELD: oil and gas production. SUBSTANCE: to create water-shutoff barrier in washed high-permeability zones of productive formation by injecting aqueous solutions of two or more gel or precipitate-forming agents into formation, these solutions are injected in the form of 1:1 v/v mixtures of 50% aggregation-stable reverse emulsion in low-viscosity hydrocarbon solvent (gasoline, kerosene, etc.) in which 5-20% concentrate of porphyrin and asphalt-tar oil components is preliminarily dissolved. Dispersity of reverse emulsion (size of stabilized drops in "oil") should be of the same order of magnitude as the dimensions of washed high-permeability zones of formation. To initiate chemical interaction of injected gel and precipitate-forming agents, after injecting 50% reverse emulsion into washed high-permeability zones of formation and concentration of emulsion in these zones, hydrocarbon solution of reverse emulsion demulsifier is injected into formation. This leads to breakage of concentrated reverse emulsion, separation and mixing of gel and precipitate-forming agents, and therefore their chemical interaction in high-permeability formation zone to form water-shutoff barrier (cross- linked polymer composition or water-insoluble precipitate). EFFECT: enhanced efficiency of formation treatment due to prevented chemical reaction between applied agents and their adsorption under formation conditions. 4 cl, 2 tbl