Experimental study of rheological properties of aphron based drilling Fluids and their effects on formation damage

Document Type: Article

Authors

1 Department of Petroleum Engineering, Ahwaz Faculty of Petroleum Engineering, Petroleum University of Technology, Abadan, Iran.

2 Department of Chemical Engineering, Abadan Faculty of Petroleum Engineering, Petroleum University of Technology, Abadan, Iran

Abstract

Drilling  fluid is one of the most important and expensive aspects of any drilling process. Colloidal Gas Aphron (CGA) has been found e ective in controlling the ltration rate by bridging the pores of the reservoir rock; hence, reducing the formation damage. This work aims to synthesize the CGA in water based drilling  fluids to study the stability, rheology, ltration loss characteristics and formation damage properties of the resulting fluid. Besides, an investigation on type of polymer, surfactant, and their concentration e ects on the characteristics of the  fluid, as well as optimum ratios of polymers in drilling fluid was performed. Experimental results showed that Xanthan Gum (XG) provides more acceptable rheological properties (especially viscosity) in comparison to Guar Gum(GG) for preparing the base fluid. Moreover, the Sodium Dodecyl Sulfate (SDS) produces more stable micro-bubbles than Hexadecyl Trimethyl Ammonium Bromide (HTAB) as a surfactant. Bubble size measurement to observe the e ect of polymer, surfactant type and concentration was performed. Through the experiments, the pH of the drilling fluid was monitored which proved the CGA introduced the best performance around a pH of 9. Furthermore, a XG/GG ratio of 3:1 is suggested to reduce the cost while maintaining the
fluid properties.

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