A Study on the Preparation and Stability of Emulsified Acid for Carbonate Matrix Acidizing

Abstract

This study presents the preparation and stability of emulsified acid for carbonate matrix acidizing. Cationic and nonionic emulsifiers were mixed using hydrophile-lipophile balance (HLB) values to prepare water-in-oil emulsion stable at room temperature and high temperature, and droplet and separation tests were carried out to evaluate the fluid stability. As the result, W/O emulsion with fluid stability that did not cause phase separation at room and the high temperature (90°C) was ensured. Furthermore, it was confirmed that the use of two emulsifiers resulted in superior outcomes compared to using cationic emulsifiers or nonionic emulsifiers individually. Therefore, the proposed results can be utilized as guidelines for the preparation of emulsified acids in carbonate reservoirs.