Life of Field Energy Performance

Abstract

Abstract BP has, in collaboration with the Norwegian Petroleum Directorate (NPD), conducted an energy performance study based on life of field data's from the Norwegian Continental Shelf (NCS). This paper shares lessons learned from this work, in terms of methodologies, energy performance, and measures to improve energy efficiency. Key observations from the study: the energy performance level on the NCS is excellent, BP has developed a new tool that improves the understanding of energy performance and identifies where energy could be saved and commercial values created, energy consumption on oil producing platforms is fairly constant whereas the % energy consumed increases significantly as a field matures. Introduction BP's philosophy is that improved energy efficiency can contribute both towards stabilization of greenhouse gases (GHG) in the atmosphere and also adding commercial value to the company's shareholders. Understanding energy performance is an important part of this value adding exercise. BP has therefore developed a new tool to reveal the energy performance on platforms in order to identify potential improvements. One objective of this study was to test different methodologies for revealing energy performance by using high-quality production and energy usage profiles. Three BP assets were examined in depth, named Field A, B and C. These are medium-sized oil fields with some associated gas. Methodology Energy and emissions performance can be estimated from different methodologies. One indicator is the percentage energy consumed (fuel, flared or vented) compared to the quantity of oil and gas exported:Equation This metric is easy to communicate and calculate. However, as will be presented, the metric has certain limitations. In general, a life of field energy metric below 2%, i.e. equivalent to ~ 40 kg CO2 per net produced Sm3 oil equivalent, is considered as good performance. However, each field has specific natural characteristics e.g. gas/oil ratio, reservoir performance, injection strategy (water, gas or depletion), field-size, crude oil quality (heavy or light), oil & gas export specifications and pressures etc. Such variations complicate the comparison of the actual energy performance across fields. One field specific aspect is the calorific value of the natural gas. Fields that feed their gas turbines with rich gas can consume less volume; hence gain an advantage when % energy metrics are compared. In order to examine this effect we have calculated the energy metric based upon the energy consumption in terms of barrels of oil equivalent (boe) and energy (GJ). Best-in-Class model In order to identify potential energy improvements and to reveal if the consumed energy on a platform is justified or not, a Best In Class (BiC) energy performance-benchmarking model has been developed by BP, in collaboration with Genesis. This model calculates an oil/gas field's actual energy performance over the field life. Further, it identifies the gap between actual performance and what could have been achieved in the case of optimal energy efficiency design and operation. The model identifies potential energy savings, which makes it an important step forward from high-level indicators such as the percentage hydrocarbon loss energy metric, or CO2 emission per produced Sm3 o.e. The BiC model calculates an energy benchmark that reflects the circumstances of the operation. This methodology seeks to review:Key energy consuming processes: compression, pumping, injection, generation of shaft power etc.Key design parameters that influence the energy consumption: flow rates, pressures, injection rates etc over life of field