Abstract:

The effective acid penetration distance is an important parameter in acid-fracturing treatment design and has treat influence upon the effect of the treatment. The temperature in a fracture and the acid-rock reaction products simultaneously affect the acid penetration greatly. But up to mow, no information concerning this aspect has been published.
For satisfying practical requirements of calculation in the treatment design, this paper developes a new mathematical model for reaction of acid flowing in the fracture by taking principal factors affecting the effective penetration of the acid into consideration. This model is combined with the model of temperature distribution in a fracture, the model of velocity field and the model of acid-rock surface reaction kinetics to give their solution simultaneously and a corresponding computer program has been established to give a system calculation. Figures and tables of data on the influences of common ion effect, acid concentration, formation temperature and heat generated by the acid-rock reaction on effective acid penetration distance have been obtained by analyzing and correlating.
The computer program and calculations obtained in this paper can be used in practical acid-fracturing treatment design.