استفاده از بيوپليمرهاي پلي‌ساكاريد (گوار و زانتان) به‌عنوان عامل ژل‌شدگي درجا در فرايند اسيدكاري چاه‌هاي نفت و گاز، جهت توليد اسيد كندكار و انحراف اسيد

Acidizing is one of the effective methods for stimulating oil wells. By injecting acid into the formation, it creates new flow paths, increases permeability, an‎d reduces the skin factor in the near-wellbore region. This method is particularly applicable to carbonate reservoirs, which make up a major portion of Iranʹs an‎d the worldʹs reservoirs. Due to the high temperature of the wellbore, the reaction between the acid an‎d carbonate rock is very rapid, an‎d a significant portion of the acid is consumed in the near-wellbore areas, thus reducing its penetration into the reservoir depth. To control the reaction rate an‎d increase the depth of acid penetration, the use of retarded acids has gained attention in recent years. In this study, two biopolymers, Xanthan an‎d Guar, have been used as retarding additives in 15% hydrochloric acid. Due to its viscosifying properties an‎d amphiphilic nature, Xanthan is capable of forming both gelled acid an‎d emulsified acid. The aim of the study is to eva‎luate the retarding behavior of these two types of acids at different concentrations. To this end, various experiments have been conducted, including measurements of the acid-rock reaction rate, compatibility with the reservoir rock, an‎d thermal stability at temperatures of 25, 50, an‎d 90°C. All experiments were performed using bottle tests under atmospheric pressure.The experimental results indicate that xanthan- an‎d guar-based gelled acids, as well as xanthan-based emulsified acid, reduce the acid–rock reaction rate at all three investigated temperatures compared to conventional acid. Accordingly, weight loss reductions of 15.21%, 17.01%, an‎d 29.85% were obtained for xanthan gelled acid, while the corresponding values for guar gelled acid were 17.28%, 18.83%, an‎d 30.63%, respectively. These results suggest that xanthan biopolymer exhibits more effective retardation performance than guar. Furthermore, the emulsified acid showed weight loss reductions of 13.36%, 15.02%, an‎d 28.21%, indicating that xanthan-based emulsified acid performs better than gelled acid. Overall, the results demonstrate the effective retardation behavior of both gelled an‎d emulsified acids formulated using these two biopolymers.

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محسن محمدي , حميدرضا شاه وردي