Study of a strong inhibitory solid-free drilling fluid

¹ Shaanxi Province Key Laboratory of Environmental Pollution Control and Reservoir Protection Technology of Oilfields, Xi’an Shiyou University, Xi’an, 710065, China
² Xi’an Key Laboratory of Tight oil (Shale oil) Development, Xi’an Shiyou University, Xi’an, 710065, China
³ CNPC Chuanqing Drilling Engineering Company Ltd., Xi’an, 710018, China

^* Corresponding author: zhangli@xsyu.edu.cn

Abstract

The study on the problem of hydration and dispersion expansion of shale and the poor high temperature resistance and lubrication performance of mud with soil is carried out. The selection of viscosity enhancer, filter loss reducing agent, lubricant and inhibitor in solid-state drilling fluid was carried out through experiments. The formula of solid-free drilling fluid was 0.2% 1831+1% xanthan gum+1% phenolic resin and 1% sodium benzenesulfonate. The linear expansion rate of bentonite is less than 20%, which shows that the formulation has good inhibition performance. The mud ball in the drilling fluid after 48 h of storage did not undergo hydration expansion, which indicated that the formulation had strong inhibition on the hydration expansion of clay. Finally, after heating the formula in a roller heating furnace at 120 °C for 16 h, the plastic viscosity, dynamic shear force and apparent viscosity of the formula were determined as 14.00 mPa·s, 24.00 Pa and 39.50 mPa·s respectively, while FL (filtration loss) was 17 mL. In conclusion, the strong inhibition solid-phase drilling fluid formula is superior in both the inhibition of hydration expansion and the high temperature resistance of clay.