Etched surface morphology analysis experiments under different reaction rates

Abstract

Etched surface morphology is the main cause of etched fracture conductivity. It would be helpful to optimize acidification fracturing design and improve the reservoir reconstruction effect by analyzing the rock etched surface during the acid-rock reaction process. The chemical mechanism involved in forming the etched carbonate surface and reasons for non-uniform morphogenesis are thoroughly analyzed in this paper. By applying different viscous acid-rock reaction kinetic parameters, a measuring device, and a 3D laser scanner, the acid-rock reaction rate and etched surface morphology are tested under different acid concentrations, reaction temperatures, and flow rates. The regularity of the surface morphology is also obtained under different acid-rock reaction rates. The results demonstrate that, with an increase in the acid concentration, reaction temperature, and acid flow, the acid reaction rate can be accelerated and the etched masses are positively related to the etched volume and acid-rock reaction rate. The main controlling factors of the acid-etched surface morphology in the parallel and vertical acid flow directions are the acid-rock reaction rate and mineral composition distribution, respectively. The increase in the acid-rock reaction rate contributes to drastic changes in the rock wavy surface, as well as the differences in and degree of inhomogeneity. In the acid flow direction, it is more conducive to form acid-etched holes and grooves by increasing the acid-rock reaction rate.