diffusion, dissolution rate.
Diffusion coefficient for the reaction of carbonate rocks dissolution in acid fracturing fluids was measured using rotating disc. Four types of fracturing fluids and two types of carbonate rocks were used. It has been found that for all available speeds of the apparatus, the reaction rate increases with increase of angular rate of the disc, therewith, predominant dissolution of calcite rather than dolomite takes place. It has been demonstrated that at high fracturing pressure, the diffusion is almost insensitive to Neftenol K added to the acid solution, while in the Chevron-Phillips fracturing fluid the diffusion decreases by one-two orders of magnitude, and in acid-oil emulsion fluid it decreases by three orders of magnitude. The measurementsвЂ™ results were entered into the MFrac acid base.
1. Rozieres J. et al., Measuring diffusion coefficients in acid fracturing fluids
and their application to gelled and emulsified acids, Paper SPE 28552.
2. Anderson M.S., Reactivity of San Andres dolomite, Paper SPE 20115.
3. Taylor K.C., Nasr-El-Din H.A., Measurement of acid reaction rates with the rotating disk apparatus, Paper SPE 2007-015.
4. Taylor K.C. et al., Measurement of acid reaction rates of a deep dolomitic gas reservoir, JCPT, October 2004, V. 43, no. 10, pp. 49-56.
5. Lund K. et al., Acidization-II. The dissolution of calcite in hydrochloric acid, Chem. Eng. Sci., 1975, no. 30, pp. 825-835.
6. Hoefner M.L. et al., Role of acid diffusion in matrix acidizing of carbonates, JPT, February 1987, pp. 203-208.
7. Stilbs P., Moseley M.E., Multicomponent self-diffusion measurement by the
pulsed gradient spin-echo method on standard Fourier transform NMR pectrometers, Chem. Scripta, 1980, no. 15, 176 p.
8. Levich V.G., Fiziko-khimicheskaya gidrodinamika (Physical and chemical
hydrodynamics), Moscow: Gos. Izd. fiziko-matematicheskoy literatury Publ., 1959, 699 p.
9. Hansford G.S., Litt M., Mass transport from a rotating disk into power law liquids, Chem. Eng. Sci., 1968, no. 23, pp. 849-864.
10. Plummer L.N., Busenberg E., The kinetics of dissolution of dolomite in CO2 вЂ“
H2O systems at 1,5 to 65В°C and 0 to 1 atm PCO2, Amer. Jour. of Sci, 1982, V. 282, pp. 45-78.