Energy efficiency of oil and gas production plant operations

Abstract

The exploitation of subsurface resources is an energy-intensive activity leading to substantial emissions. The main energy consumer for hydrocarbon production is gas compression and pumping. In this article, we investigate the effect on energy use from changes to compressor and pump layout, with a particular focus on offshore platforms. We have developed a workflow for the optimization of compressor and pump layout and settings, where the optimization objective is the minimization of energy use. The introduced workflow is demonstrated on simulated data from an offshore field. We first compared how the interval between operational changes to the processing plant affects energy use and observed significant reductions in energy use when increasing the number of operational changes, e.g., a 7% reduction when moving from quarterly to monthly changes and an additional 5% reduction when moving to weekly changes. However, the reductions diminish with an increasing number of operational changes. This indicates that more sophisticated processes such as fully automatic operations to change the setup continuously are not a necessity for efficient operations, considering practical and operational limitations to changes in equipment layout. Increasing the degrees of freedom by allowing for changes to the rotational speed, both for compressors and pumps, yields an additional reduction in energy use, thereby reducing associated emissions. The increased flexibility of changes to the rotational speed gave an energy reduction of 9% on average for our test case. In addition, our study shows a strong correlation between energy efficiency and the amount of gas needed to prevent surge in the compressors.