Testing a novel life cycle assessment based framework for produced water management from offshore oilfield operations

As worldwide reliance on the petroleum industry persists, environmental concerns associated with offshore oilfield operations continue to present a critical challenge for sustainable management. This study develops and tests a novel life cycle assessment (LCA)-based framework to examine strategies for produced water (PW) management from offshore oilfield operations. The framework encompasses experimental designs under a dynamic modelling system coupled with stepwise linear regression, multi-criteria decision analysis (MCDA), and fluctuating scenarios in Enhanced Oil Recovery (EOR) and other internal reuse options including cooling systems, drilling operations, and utility services. Two strategies for treatment train technologies were tested with various PW compositions, sludge management options, and variable EOR demands. When comparing conventional (corrugated plate interceptor, hydrocylone and nutshell filter) with recent treatment/disposal technologies (tubular separation, combined fiber coalescence and mechanical vapor compression), the LCA revealed that the latter increased operational efficiency (14%), reduced cost (6.5%) and the overall environmental impact categories (66%). The scenario that exhibited the lowest emissions incorporated recent treatment technologies and land application for sludge management. This configuration demonstrated considerable environmental advantages, evidenced by significant reductions in key impact indicators including freshwater eutrophication (74%), global warming (64%), marine ecotoxicity (58%), and stratospheric ozone depletion (44%) when compared to the baseline scenario with conventional treatment-disposal methods. The system dynamics model revealed that the internal reuse options exploited 23%–47% of PW inflow, indicating a significant annual surplus of unused PW that presents an opportunity for external applications to enhance sustainability. In closure, we argue that the proposed framework offers a valuable tool for waste management practitioners, facilitating the identification and selection of strategies with minimal environmental impacts for PW management.