Extended modelling framework for combined subsurface-topside optimisation

Research Scientist
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Energy consumption in the petroleum production process can be divided into three main contributors, namely reservoir depletion techniques, transport techniques and processing and export of produced fluids.

Key researchers: Handita Reksi Dwitantra Sutoyo (NTNU), Carl Fredrik Berg (NTNU) and Heiner Schümann (SINTEF).

While the individual contribution of each part is field dependent, the general trend shows that energy intensity (and thus emission intensity) of a field typically increases rapidly with declining production rate. This is reflected in all aforementioned parts.

Still, todays planning and optimisation approaches typically address these areas independent of each other. The interdependencies, however, become more crucial when emission intensity is defined as an optimisation objective in addition to high recovery rate. As an example, the optimum depletion strategy might require changes in the topside pressure setpoints during the field's lifetime. The choice and configuration of processing systems must enable the depletion strategy. However, focusing on overall emission reduction might introduce limitations set by the processing equipment.

As part of a PhD project, an integrated modelling and optimisation framework considering subsurface and topside modelling is developed. This will enable correctly handling the interdependencies of topside and subsurface processes and predicting important feedbacks in terms of changed production (subsurface) or energy consumption. Combined optimisation of system design, unit operation and depletion strategy will be possible in one step.

The code is written in Python and will be open source. Most recent activities focused on implementing more realistic models for processing equipment correctly relating energy consumption to unit performance.