Enhancing Production from Mature Oil Wells Through Production Logging–Driven Interventions

Abstract

Mature oil wells are commonly characterized by declining production rates, increasing water cut, lift limitations, and increasing uncertainty in zonal contribution. These challenges arise from reservoir depletion, evolving fluid distribution, changing wellbore flow dynamics and may result in conservative operational choices and premature well abandonment. A key limitation in late-life well management is the reliance on surface production data, which provide only aggregated well performance and do not adequately capture downhole flow behaviour. Surface measurements alone are insufficient to resolve zonal contribution, identify water-producing intervals, or detect inter-zonal crossflow, particularly in wells completed across multiple flow units within a reservoir with no distinct fluid composition. In many mature assets, production logging is often deployed on a reactive basis or deferred due to operational constraints and cost considerations. As a result, intervention decisions are frequently made using incomplete or indirect data, increasing the likelihood of misdiagnosis and ineffective operations. Production logging provides a reliable means of evaluating well and reservoir performance under dynamic conditions, enabling identification of zonal contribution and flow behaviour along the wellbore. When integrated into a structured workflow, it improves diagnostic confidence and supports effective intervention planning. Production logging tool (PLT) data acquired under both flowing and shut-in conditions were integrated with historical production performance, static pressure surveys, and completion configurations to improve understanding of downhole flow behaviour relevant to intervention decision-making. The analysis revealed uneven zonal contribution, with certain intervals continuing to produce oil while others were dominated by water production. In some cases, inter-zonal crossflow during shut-in conditions masked true reservoir performance, resulting in restart difficulties and unstable production behaviour. Insights from PLT interpretation were used to design targeted light well interventions, including selective isolation of non-contributing or high water-producing intervals while preserving oil-bearing zones. These interventions were implemented without escalating to major workovers. Application of the PLT–driven workflow resulted in stabilized oil production, improved performance of remaining oil-bearing zones, and extension of productive well life. While the analysis is based on a single well case, the observed challenges and diagnostic outcomes are representative of common issues encountered in mature oil wells completed across multiple intervals. The workflow presented in this study is therefore broadly applicable and provides a practical framework for production optimisation and intervention planning. The study demonstrates that production logging as a decision-support tool, provides significant value in optimizing mature oil wells and minimizing unnecessary well abandonment.