A biosurfactant for inhibiting clay hydration in aqueous solutions: Applications to petroleum industry

Abstract

The development of high performance and environmentally-friendly clay stabilizers is still crucial to the drilling industry. This study aims to evaluate the impact of mulberry leaf extract (MLE), a biosurfactant as a clay stabilizer, on hydration of sodium bentonite in aqueous solutions. Several experimental techniques including sodium bentonite inhibition, sedimentation, filtration, zeta potential, particle size, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) are utilized in this study. Based on the results, MLE aqueous solution loads a larger amount of sodium bentonite in contrast to deionized water, leading to a low rheological profile. Sodium bentonite is not able to form a stable dispersion in the MLE aqueous solution. The capability of sodium bentonite to control the fluid loss is considerably lost upon exposure to the aqueous solutions of MLE. In the presence of MLE, the zeta potential of sodium bentonite dispersion shifts towards positive values, implying the instability of the water film surrounding the sodium bentonite particles. Sodium bentonite particles are larger in the MLE aqueous solution, representing a lower degree of particle delamination. A lower water content is observed in TGA for sodium bentonite modified by MLE. In SEM analysis, sodium bentonite particles show larger aggregates in the MLE aqueous solution. MLE aqueous solutions also have larger shale cuttings, in contrast to deionized water. All experiments confirm the promising features of MLE as an excellent clay stabilizer during drilling through clay rich shales. In addition to the superior performance in the drilling industry, MLE exhibits an environmentally-friendly characteristic which is an asset for this biosurfactant.