Numerical investigation of fluid phase momentum transfer in carbonate acidizing

Abstract

This work mainly studies the effect of fluid phase momentum transfer mechanisms on the acidizing results, including the retardation effect of the porous structure and the interaction between the fluid phase, such as viscous dissipation and inertial effect. The results show that the acid fluid momentum transfer is influenced by the complex porous structure and fluid viscous dissipation. Eventually, the Stokes-Darcy equation is recommended to be adopted to describe the fluid phase momentum transfer in the following numerical simulation studies of the carbonate acidizing process. Based on this model, a parametric research is carried out to investigate the impact of acid on rock physical characteristics in the stimulation process. Increasing the acid concentration appears to minimize the quantity of acid consumed for the breakthrough. The acid surface reaction rate has a considerable impact on the pore volume to breakthrough and the optimum acid injection rate. The influence of permeability on the acidizing results basically shows a negative correlation with the injection rate. The difference between the acidizing curves of different permeability gradually becomes insignificant with the decrease in injection rate. The existence of isolated fracture and vug significantly reduces acid consumption for the breakthrough.