Evaluation of Wellbore Integrity in Aging Oil Wells in the Niger Delta: A Case Study of Shell Petroleum Development Company Assets in Rivers State

Wellbore integrity is a critical operational concern for aging oil wells across the Niger Delta, where decades of production have exposed casing and cement sheaths to progressive mechanical and corrosive degradation. This study evaluates the wellbore integrity status of selected aging wells operated by Shell Petroleum Development Company in Rivers State, South South Nigeria. A descriptive case study design is adopted, drawing on historical well records, corrosion inspection logs, and casing inspection tool data obtained from SPDC's asset integrity database for wells with production histories exceeding twenty years. Integrity failure indicators including sustained casing pressure, annular gas migration, and cement bond log responses are systematically assessed. The study applies the API RP 90 standard for annular pressure management as the primary evaluation framework. Findings from the data review indicate that approximately 38 percent of assessed wells exhibit measurable annular pressure anomalies attributable to cement sheath deterioration, with wells in high-salinity formations showing accelerated corrosion rates. Remediation options including squeeze cementing and chemical casing patch techniques are evaluated in terms of technical feasibility and cost-effectiveness under current field conditions. The study concludes with prioritisation recommendations for integrity remediation programmes, emphasising the role of regular casing inspection scheduling in extending well productive life. Keywords: wellbore integrity, aging wells, Niger Delta, casing corrosion, annular pressure.