Experimental study of rheological properties of aphron based drilling uids and their e ects on formation damage

Drilling uid 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 uids to study the stability, rheology, ltration loss characteristics and formation damage properties of the resulting uid. Besides, an investigation on type of polymer, surfactant, and their concentration e ects on the characteristics of the uid, as well as optimum ratios of polymers in drilling uid 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 uid. 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 uid 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 uid properties.