Taro Mucilage as Green Inhibitor in Water-Based Drilling Fluid to Modify the Rheological and Filtration Properties and Mitigating Shale Swelling Characteristics

Abstract

Abstract Clay bearing shale formations tend to swell upon contact with water-based drilling fluid. The migration of hydrogen ions into the nano-spacing of shale platelets is mainly responsible for its disintegration and swelling. To mitigate the clay swelling problem, various shale stabilization materials are added in the water-based muds (WBMs). Before adding these additives, it is crucial to understand their physical and chemical interactions with clay minerals as well as within fluid. In this study, Taro Root Mucilage (TRM) is used as a green chemical in WBM to decrease the shale swelling characteristics. Taro root was boiled in distilled water at 40°C for 24 h and mucilage was prepared, which was characterized by FTIR and XRD pattern. It was then made part of a mud system, which then interacted with the shale sample collected from the western zone of Pakistan. Moreover, this mucilage was compared with sodium alginate mud system, a biopolymer commonly used in industry. The results of the experimental studies showed that TRM appreciably reduces clay swelling characteristics compared with the distilled water and sodium alginate. Moreover, all the rheological parameters fall under the recommended API range for TRM samples. Furthermore, it was found that the TRM produces a thin filter cake and minimizes fluid loss volume. In addition, during the shale cutting recovery test, 50%, 80% and 100% recoveries were obtained from base mud, whereas 10% and 20% were obtained from TRM based WBM respectively. TRM encapsulates the drilled cutting and preserves it from breaking into smaller fragments. In addition, TRM concentration in drilling mud increases the hydrophobicity of the shale sample. The adsorption of TRM over the surface of shale allows less penetration of water in the nano-spacing of shale structure and improves the shale stability. Hence, the finding in this article implies that TRM can be used as a green and sustainable substitute for traditional clay stabilizers in drilling operations to reduce formation damage. It has all the desired properties that help it to become an alternate solution in the form of a clay swelling inhibitor.