Petrophysical and Geomechanical Integrated Approach to Mitigate Formation Damage and Non-Productive Time in Pliocene Progradational Submarine Fan Reservoirs, East Nile Delta, Egypt

Abstract

Drilling in the East Nile Delta has been challenged due to Non-Productive Time, formation losses, and cost overruns. This study integrates petrophysical and geomechanical analyses of five wells targeting the Lower Pliocene–Pleistocene gas-bearing sandstones to elucidate the interplay between reservoir quality and operational performance. Wells-1 and -2 exhibit superior reservoir properties (net pay >64 m, porosity >28%, Sw ≈30%), while Wells-3 and -4 show moderate quality, and Well-5 was dry. Despite similar petrophysical profiles, production varied significantly, prompting a root-cause investigation. Findings reveal that excessive mud weights—especially during instability events—led to filtrate invasion and pore throat blockage, causing formation damage in Wells-1 and -4. Geomechanical modeling indicates that wells drilled sub-parallel to the minimum horizontal stress (Sh_min) required higher mud weights to maintain borehole stability, increasing the risk of damage. The study emphasizes the necessity of integrating petrophysical and geomechanical data to optimize mud weight selection, improve wellbore stability, and reduce NPT. Real-time geomechanical monitoring and formation-compatible drilling fluids are recommended to enhance drilling efficiency and reservoir deliverability in deltaic sandstone settings.