Dissolution kinetics of analcime in hydrochloric acid

Abstract

Acidization of petroleum reservoirs has been used for many years to increase the productivity of petroleum wells. In a number of offshore oil wells, the formation sands are extensively cemented with analcime. Recently, problems with whit powder and fine granular siliceous materials have been found after acidization. This study investigated the rate of analcime dissolution as a function of hydrochloric acid concentration and temperature by using a batch reactor. The rate of dissolution increased with increasing hydrochloric acid concentration and temperature and followed first order kinetics. For hydrochloric acid concentrations in the range of 0.1-4 mol/l, analcime was dissolved in a stoichiometrically uniform manner. There was complete decomposition and dissolution of the analcime framework under these acid solutions. However, at a hydrochloric acid concentration of 7 mol/l, aluminum was preferentially dissolved and a silica gel was formed. Analcime dissolution was further investigated using differential reactor at various flow rates in order to determine the rate-limiting step of the dissolution reaction.