GIS-Based High-Consequence Modeling for Onshore Hydrocarbon Facilities: A Case Study from Egi, Niger Delta

Abstract Oil and gas operations in the Niger Delta are characterized by complex infrastructure networks that pose significant environmental and socio-economic risks in the event of operational failures. Traditional environmental assessments often lack spatial precision in identifying areas most vulnerable to spill impacts, limiting their effectiveness for proactive risk management. This study introduces a Geographic Information System (GIS)-based approach for high-consequence modeling within an onshore hydrocarbon production facility in Egi, Rivers State, Nigeria. The methodology integrates multiple spatial datasets—including pipeline routing, wellhead locations, flowstation footprint, land use/land cover classification, slope gradients, and environmental sensitivity indices—to generate composite risk surfaces. These layers were analyzed to delineate zones with the highest potential impact under spill scenarios. Results indicate that approximately 52.1% of the 73.234 km² study area falls within high-consequence zones, with pipelines contributing the largest share (63.02% of total impact area). Light vegetation emerged as the most affected land cover type, underscoring ecological vulnerability. The findings demonstrate the value of GIS-driven consequence modeling for pipeline integrity management, emergency response planning, and regulatory compliance under frameworks such as EGASPIN 2018 and NOSCP. This approach provides operators and regulators with actionable insights to prioritize monitoring, allocate resources efficiently, and enhance environmental stewardship in sensitive oil-producing regions.