Integrating Subsurface Data to Unlock Bypassed Gas in a Shallow Reservoir

Abstract

Mature assets often experience severe water encroachment, leading to premature abandonment especially in gas reservoirs, despite the presence of significant bypassed gas. This study demonstrates how integrating subsurface data with advanced saturation logging can identify and derisk untapped gas resources in a watered-out environment. Saturation logs revealed high gas saturation within lower reservoir sand packages previously overlooked during initial completions. Through petrophysical re-evaluation, fluid contact mapping, and connectivity analysis, the commercial viability of this gas-bearing zone was confirmed. A candidate well was selected for intervention based on structural positioning, integrity, and accessibility. A targeted recompletion strategy was executed, isolating water-swept intervals and perforating gas-rich sections. Post-intervention results delivered 300 KSm3/d of gas with a condensate yield of 500 bopd (≈2,600 boepd), achieving payback in just 49 days. Subsequent pressure build-up analysis indicated near-wellbore heterogeneities and close boundaries, providing additional insights into well operability. This case underscores the critical role of integrated subsurface workflows in enhancing dynamic reservoir understanding, maximizing recovery from mature assets, and providing a cost-effective pathway for extending field life through bypassed gas exploitation.