<p>This work proposes a new methodology to evaluate production forecast, economic return, energy demand, and carbon emissions of an oil field with multiple reservoirs sharing the same production facility in a scenario of uncertainty. Using a benchmark case, the reservoir performance forecasting for this scenario is evaluated on two categories of parameters: (1) reservoir and operational uncertainties and (2) management of the shared platform capacity. The first is evaluated by applying these uncertainties to two reservoirs in an integrated production strategy. The second, generally unconsidered, is evaluated through production and injection share ratios for each reservoir. Both parameter categories generate optimized probabilistic output variables and risk curves of cumulative production and injection, net present value, total carbon dioxide emitted, and energy demand. The cumulative production and injection of the platform are much more impacted by the share ratio adopted than by the uncertainties of the reservoirs and operations. The net present value, energy demand, and total carbon emission followed a similar behavior. The cumulative oil production per total carbon emissions and per energy demand were also less affected by reservoir and operational uncertainties. Net present value (+ 6%), cumulative oil production per total carbon emissions (+ 35%) and per energy (+ 50%) demand indicators resulted positively by share ratio compared with separate reservoir production, indicating gains related to the management of the shared production system. This work presents a referenced uncertainty assessment methodology to combine and evaluate production of multiple reservoirs of an oil field. Comparing objective functions focused on production, financial return, energy efficiency and carbon emission, it brings important issues for decision making in sustainable projects.</p>