SOLID REAGENT FOR ACID TREATMENT OF WELL AND PROCESS OF ACID TREATMENT OF WELL, PREFERABLY WATER-SUPPLY WELL Russian patent published in 2008 - IPC C09K8/78 E21B43/27 

FIELD: mining industry.

SUBSTANCE: invention preferably relates to treatment of water-supply wells exposing sand producing formation and producing drinking, mineral, and industrial waters, mineral solutions, etc. Solid reagent used in this operation contains 37.5-73.2% of nitric acid/urea reaction product and 24.4-61.5% of oxygen-containing sulfur compound, the rest being sodium polyphosphate. Process solution, which is 10-30% solution of above-indicated solid reagent, is supplied to well provided with filter descended by means of tubing string, injected into formation through reagent conduit, and held in formation during a certain time, after which the well is pumped through. When process solution is held in formation, it is made to reciprocate with the aid of compressed air periodically injected to pressure-sealed wellbore, after which wellbore is depressurized. During the period of time when compressed air is injected, level of fluid in wellbore is lowered below static level at a distance not exceeding length of filter and time point when fluid reaches lower end of the filter is recorded. When this time point is stabilized, reciprocation of process solution is ended. When performing subsequent pumping of well, specific electrical resistance value of fluid pumped out of well is also measured and, when this value approaches or attains the value of specific electrical resistance of the formation fluid, pumping is terminated.

EFFECT: increased dissolving capacity of solid reagent for dehydrated ferruginous mudding deposits and prevented subsequent deposition thereof within near-filter zone, enhanced treatment efficiency due to increased permeability near-filter zone of formation, and intensified dissolution of mudding deposits.

6 cl, 6 tbl, 2 ex