Foam-Acid Treatment of Formations
The foam-acid treatment of formation is done by injection of aerated or gassed
acid solution into it. To stabilize the foam system the acid solution is treated with
surface-active substance.
In contrast to acid solution, which in connection with carbonate rock reacts
quickly in the borehole critical area and is fully neutralized, the foam-acid
neutralizes very slowly and it is possible to influence upon remote zones of
treatment.
The main advantage of the foam-acid treatment in comparisson with treatment by
acid solution is its ability to increase repeatedly the scope of the treated formation
on account of penetration selectivity of the foam-acid into crevices with different
permeability.
Besides, the high resilient energy of the aerated solution makes it possible to
remove effectivelly products of reaction from the formation.