Okra mucilage as environment friendly and non-toxic shale swelling inhibitor in water based drilling fluids

Abstract

Water-based muds (WBMs) cause severe formation damage during the drilling operation when interacting with clay-containing formations. To avoid clay swelling, it is common practice to add swelling inhibitors in WBMs. It is extremely important to have an understanding of the physicochemical interactions of such inhibitors with clay formation and their impact on drilling muds. The study reports the application of Okra mucilage as a clay swelling inhibitor. Okra mucilage was extracted from okra by heating it in distilled water at 40 °C temperature for several hours. Swelling inhibition was evaluated by conducting a linear swelling test, a capillary suction timer (CST), zeta potential, and particle size. Rheology and filtration experiments were conducted to evaluate the performance of Okra mucilage contained drilling muds. The experimental investigations showed the inhibition potential of Okra mucilage. The Okra mucilage reduced the clay swelling appreciably as compared to distilled water. Moreover, the Okra mucilage showed comparable performance to a commonly used clay stabilizer (KCl) used in the industry. It was observed that Okra mucilage reduced the fluid loss and provided a thin filter cake. The rheological properties were improved with the addition of Okra mucilage. The increase in clay particles and reduction in zeta potential showed the inhibition properties of the Okra mucilage. In addition, Okra mucilage reduced friction and provided lubricity. The proposed Okra mucilage could be a green and environmentally friendly alternative clay swelling inhibitor.