Research on Low Dosage Clay Stabilizer for Shale Gas Fracturing Fluid

Abstract

When the water-based fracturing fluid used in shale oil and tight oil fracturing enters the formation, the hydration expansion and dispersion migration of water-sensitive minerals will reduce the formation permeability and affect the stimulation effect. And the construction site of large liquid volume, high displacement, namely with injection, construction technology requirements as low as possible additive dosage. Taking the linear expansion rate of bentonite as the evaluation index, quaternary ammonium salt cationic compound A was selected from four types of clay stabilizers. When the mass concentration is 2 g/L, the anti swelling rate is 89%, which can be used for clay anti swelling of water-based fracturing fluid. The mechanism of the clay stabilizer was studied by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the quaternary ammonium salt cationic compound does not enter the crystal layer of bentonite, but through electrostatic adsorption and hydrogen bonding to encapsulate and combine bentonite, effectively inhibiting hydration, dispersion and expansion [1, 2]. It is found that in order to achieve the same anti swelling performance, the amount of clay stabilizer entering the crystal layer of bentonite needs to be higher.