Cationic gemini surfactants containing biphenyl spacer as shale swelling inhibitor

Abstract

The inhibition of shale from swelling and hydration is the primary concern in the drilling process of the oil and gas industry. In this study, the effect of two gemini surfactants having biphenyl spacer and different counterions (chloride and bromide) on rheology, filtration, and shale inhibition properties were investigated at different concentrations (0.05 wt%, 0.1 wt%, 0.2 wt%). The rheology and filtration characteristics were evaluated at the various concentration for two gemini surfactants. The shale inhibition characteristics were determined by capillary suction time test and linear swelling experiments. XRD analysis was performed to study the d-spacing of clay and the intercalation behavior of clay for both gemini surfactants. The stability of prepared drilling fluids with gemini surfactants was assessed by particle size distribution experiments. The wettability alteration of clay surface with gemini surfactants was determined by contact angle measurements. The experimental results showed the significant improvement in the shale inhibition characteristics of shale by reducing the linear shale swelling rate to 97.7% and 101% for the gemini surfactants with chloride counter ion (BPC) and gemini surfactants with bromide counter ion (BPB) respectively, at 0.2% concentration in the drilling fluid. The capillary suction time was significantly reduced to 312 s and 636 s for BPC and BPB, respectively, at 0.2% concentration. XRD analysis of clay exhibited that d-spacing increased after treating with gemini surfactants that indicate the intercalation of clay particles. All the experimental results showed that gemini surfactants having biphenyl as a spacer could be the possible additives of drilling fluid for the inhibition of shale.