Omid Sharifi - Department of Petroleum Engineering, Islamic Azad University of Omidieh Branch, Omidieh, Iran
Saeed Parvizi - Department of Petroleum and Natural Gas Engineering, Sahand University of Technology, Tabriz, Iran
Saeed Khezerloo - Department of Petroleum Engineering, Amirkabir University of Technology, Tehran, Iran
Samaneh Ghorbanpour - Department of Petroleum Engineering, Islamic Azad University of Mahshahr Branch, Mahshahr, Iran

Aphron fluids are a special type of foam in which the gas bubble (air or any other gas) is surrounded by a double-walled layer consisting of surfactant and polymer. Therefore, it is more stable at high temperature and pressure conditions due to being preserved by three layers. These fluids are widely used in industry. Today, the industry uses various polymers such as acrylamides, polyacrylamides, and hydrolyzed acrylamides that are harmful to the environment. In this study, the possibility of using natural and biodegradable polymers such as Astragalus Gum and starch is investigated. The results showed that the Aphron fluid made from Astragalus Gum (extracted from a dessert plant) had a higher volumetric yield than industrial polymers. Stability over time and rheological properties for Astragalus Gum are also acceptable. Also, it is found that increasing the polymer concentration increases the stability and rheological properties, but in contrast, the volumetric yield decreases. The effect of salt and surfactant concentrations is also evaluated in this research. The results show that increasing the surfactant concentration increases the volumetric yield of the fluid. Increasing the surfactant concentration from ۱ wt% to ۲ wt% increases the volumetric efficiency of Aphron fluids by ۵%. In general, according to the results obtained in this research work, Astragalus Gum’s performance is better than synthetic polymers for making Aphron fluids.

Biodegradable Polymer, Aphron Drilling Fluid, Rheological Properties