Investigation of the Effect of Sand Production on Gas Well Productivity in the Coastal Swamp Depobelt of the Niger Delta

Sand production from gas wells in weakly consolidated Niger Delta reservoirs poses significant challenges to production sustainability, equipment reliability, and environmental integrity. This study investigates the mechanisms, predictors, and productivity impacts of sand production in gas wells within the coastal swamp depobelt of the Niger Delta, drawing on production data and completion records from 22 gas wells in Bayelsa and Rivers states. The research employs an analytical mixed-method approach combining geomechanical analysis of available rock mechanics data, sand production history analysis using particle size distribution records, and productivity impairment quantification through nodal analysis models constructed in PROSPER software. The study develops a sand onset prediction model for coastal swamp wells calibrated against the specific unconfined compressive strength (UCS) and formation pressure depletion profiles documented in the study dataset. A research gap addressed is the limited published empirical characterisation of sand onset behaviour under the specific low-pressure, high-permeability conditions of coastal swamp gas reservoirs, which differ substantially from the deeper, more competent deltaic reservoirs where most published Nigerian sand production literature originates. Findings demonstrate that sand onset correlates most strongly with formation pressure depletion below 40 percent of initial reservoir pressure and drawdown rates exceeding 500 psi per day, providing quantitative operational guidance for production management. Sand production-related productivity impairment averages 22 percent of theoretical deliverability in affected wells. Recommendations include implementation of maximum drawdown rate guidelines, sand control screening criteria for completion design, and installation of downhole sand monitoring tools in identified high-risk wells. Keywords: sand production, gas well productivity, Niger Delta, geomechanics, sand control.