TREATMENT OF HIGHLY BASIC MUD USING WATER HYACINTH ASH

Highly basic drilling muds, with pH values exceeding 12, present significant operational challenges in the oil and gas industry, including accelerated equipment corrosion, formation damage, reduced additive effectiveness, and environmental concerns. Conventional pH control methods, primarily involving strong mineral acids or organic acids, are effective but expensive, corrosive, and pose environmental and safety hazards. This study investigates the potential of water hyacinth ash as a sustainable, cost-effective, and environmentally friendly alternative for treating highly basic waterbased drilling muds. Water hyacinth (Eichhornia crassipes), a highly invasive aquatic plant. The plant was processed, incinerated, and the resulting ash was characterized and incorporated into bentonite-based drilling mud formulations at varying concentrations (0%, 2%, 4%, 6%, 8%, and 10%). The mud samples were initially made highly basic using sodium hydroxide (NaOH) to simulate problematic drilling scenarios. Key drilling fluid properties, including pH, mud density, funnel viscosity, rheological parameters (plastic viscosity, yield point, gel strength), and the PV/YP ratio, were systematically evaluated following API RP 13B-1 standards. Results revealed that water hyacinth ash had no effect on mud density, which remained constant at 8.8 ppg across all concentrations. Contrary to the expected pH reduction, the addition of water hyacinth ash increased the pH at lower concentration, with a peak at 12.4 observed at 2% concentration, before declining to 11.2 at 10% concentration. This behavior is attributed to the high content of silicon dioxides (SiO2) present in the ash. The rheological properties showed marginal deterioration, with plastic viscosity decreasing from 29.5 to 29.1 cp (1.4% reduction) and yield point decreasing from 25.8 to 25.55 lb/100ft² (1% reduction) as ash concentration increased from 0% to 10%. Gel strength demonstrated significant reductions of 30% for 10-second readings and 32% for 10-minute readings, indicating improved thixotropic characteristics suitable for preventing cuttings settlement during circulation stoppages.