Rheological characterization of NA2CO3 activated calcium bentonite for oil and gas drilling applications

Abstract

Calcium bentonite was activated with soda ash (Na2CO3) at various ratios and due to the ion exchange; the original Ca-bentonite was converted to Na-bentonite. It was found that the Na2CO3 activation improves the swelling and rheological properties of the bentonite suspension. The results showed that the magnitude of the viscosity, η, elastic modulus, G′, and viscous modulus, G″, depend on the strength of the bentonite gel structure and interactions. The activated bentonite showed higher values of η, G′, and G″ compare to inactivated bentonite. A strong correlation between the bentonite type, soda ash concentration and rheological behaviour of bentonite is established.