General model of the carbonate acidizing process with different injection rate

The process of dolomite rock acidizing is considered. Theoretical analysis considers three regimes of the chemical reaction: face and uniform dissolution and wormhole formation. The general model integrates two analytical solutions of the face and uniform dissolution and semi empirical model of wormhole formation. The analytical solutions consider in the paper, appropriate data on semi empirical approach was extracted from Fredd and Fogler investigations. These solutions had been transferred to the dependence of skin factor from the specific acid injection rate, slug volume and acid concentration. The approximation of the dependence involves two Gauss functions and matches to the appropriate asymptotes (low and high injection rates) and describes the wormhole local minimum in the vicinity of critical injection rate. The proposed approximation dependence may be used in different codes for a reservoir acid treatment process. It could be the basis of the process optimization procedure with maximum productivity increase criteria and determination of optimal impact parameters such as acid slug volume and concentration, injection rate and etс.