Challenges and geological factors influencing groundwater drilling success in the Ogwashi-Asaba formation, Nigeria

This study examines the challenges associated with groundwater development in the study area, characterized by widespread abandoned drilling rigs and unsuccessful boreholes. Key issues include circulation loss, low yield, improper well completion, and geological complexities such as lignite, clay, and sandstone units within the Ogwashi-Asaba and Ameki Formation. Circulation loss, primarily occurring within lignite and porous formations, accounts for over 70% of drilling failures across various agencies notably Water Resources, Benin-Owena River Basin Development Authority, and Rapid Response Agency, with success rates ranging from 26.7% to 38.1%. The area’s lithology—comprising stiff clay, ferruginized sandstone, and weak lignite—contributes to drilling difficulties such as bit wear, pipe stocking, and slow penetration. Cross-sectional analyses reveal extensive stratigraphic correlations of these units, emphasizing their influence on drilling outcomes. To mitigate circulation loss and improve success rates, proposed solutions include the use of polymeric compounds to seal absorption channels and adopting non-rotary drilling techniques with casing. These findings underscore the critical role of geological understanding and tailored drilling strategies in sustainable groundwater resource development within complex geological settings.