Study on A New Type of High Temperature Resistant Adsorption Type Retarded Acid System

Abstract Deep carbonate reservoirs present significant hurdles for reservoir stimulation due to extreme temperatures and rapid acid-rock reactions. The dense adsorption layer has the ability to postpone the interaction between rock and hydrogen ions, which is crucial for lowering the acid rock reaction rate. Based on the surfactant and film-forming agent’s synergistic impact, the retarding agent SH-1—which has the ability to generate a dense adsorption film on the surface of rock samples—was chosen for this study. After adding synergist and corrosion inhibitor, a new type of high temperature resistant adsorption type retarding acid system ’ 0.9% SH-1 + 20% HCl + 0.1% synergist + 1.5% corrosion inhibitor ’ was developed. The retarding performance of the retarding acid system at high temperature and various parameters of acid rock reaction kinetics were studied. The results show that the new adsorption-type retarded acid system can achieve good retarding effect at high temperature and ultra-high temperature, and the retarding rate is 90 % at 180 °C. In comparison to traditional hydrochloric acid, the new adsorption-type retarded acid exhibits a lower hydrogen ion mass transfer rate and a higher acid-rock reaction activation energy. These differences can effectively lower the acid-rock reaction rate. Additionally, an examination of the etching morphology reveals that the retarded acid is more easily etched along the cracks leading to the deep core. The novel adsorption-delayed acid offers excellent retarding power, high temperature resistance, and minimal damage. Consequently, it has certain reference value for the study of acidification transformation of ultra-high temperature deep carbonate reservoirs.