A Comparative Study of Straight/Gelled/Emulsified Hydrochloric Acid Diffusivity Coefficient Using Diaphragm Cell and Rotating Disk

Abstract

Abstract A successful acid fracturing design depends strongly on the rock-acid reactivity. In carbonate reservoirs where the reaction is mass transfer limited, flow rate and diffusion coefficient determine the overall reaction rate. In an acid fracturing program, the value of the acid diffusivity is often unknown to the engineers. Quantifying diffusivity is a key step for a successful acid fracturing design. Diffusion coefficients of straight acids, gelled acids, and emulsified hydrochloric acids were measured with both the diaphragm cell and the rotating disk device. In addition, the data obtained has been utilized to develop a new correlation to predict the diffusivity coefficient of hydrochloric acid, which accounts for the effect of temperature, acid concentration, and rock type with which the acid reacts.