Investigation of Bio-Derived Materials as a Sustainable Shale Stabilizer for Water-Based Drilling Fluids in Niger-Delta

Abstract Drilling through shale-rich formations, such as those in the Niger Delta Formation, presents potential challenges, including wellbore instability caused by physicochemical interactions between shale minerals and water-based drilling fluid. These interactions cause shale swelling, dispersion, and structural weakening, leading to operational problems such as hole enlargement and bit and bottom-hole assembly (BHA) balling, which contribute to poor hole cleaning, increase the risk of stuck pipe incidents, and ultimately raise drilling costs. OBM is widely used, especially in the Niger Delta. Other alternatives like WBM or even HPWBM, still have relatively more difficulty inhibiting shales than OBM. Potassium Chloride (KCl) therefore, remains the industry-standard shale inhibitor for water-based muds owing to its ability to promote cation exchange, which reduces water migration into shale formations. However, environmental issues associated with its high salinity, particularly regarding soil and water contamination, have motivated the search for sustainable and locally sourced alternatives. This study investigates Banana Peel Powder (BPP) and Orange Peel Powder (OPP), two abundant agricultural wastes, as eco-friendly shale interaction modifiers for stabilizing dispersion-prone Niger Delta shale. Representative Niger Delta shale cuttings were characterized using XRD and XRF to determine mineralogical composition and dominant instability mechanisms, while Fourier Transform Infrared (FTIR) was used to analyze the functional groups of the processed peel powders. Water-based drilling fluids containing 1% and 3% BPP and OPP were formulated and benchmarked against uninhibited base mud and conventional KCl systems. Shale–fluid interactions were evaluated using linear swelling, hot-rolling dispersion (shale recovery), and rheological tests, with flow behavior. Experimental results were statistically validated using two-way ANOVA. Mineralogical analysis showed that the Niger Delta shale sample is predominantly quartz-rich with low expandable clay content, indicating limited chemical swelling but high susceptibility to mechanical dispersion. Despite this, the uninhibited base mud exhibited severe instability with high swelling and poor shale recovery. The incorporation of 3% BPP and OPP significantly improved shale integrity, achieving shale recoveries of 65% and 72%, respectively, closely comparable to the 75% recovery obtained with 3% KCl. Both additives also reduced linear swelling, enhanced fluid structure, and maintained stable rheological behavior after shale contamination. Statistical analysis confirmed that the inhibition performance of BPP and OPP was significant (p < 0.05) compared to the uninhibited system. Unlike KCl, which relies on ionic inhibition, the peel-based systems achieved stability through effective encapsulation and anti-dispersion mechanisms. This study demonstrates that BPP and OPP are cost effective, high performance, and environmentally sustainable shale stabilizers for dispersion-prone Niger Delta formations. Their adoption can reduce drilling costs, minimize environmental impact, and promote local resource utilization.