According to the US Environmental Protection Agency, producing electricity, heat, and industrial power accounts for nearly 50% of global greenhouse gas emissions. Identifying ways to reduce energy consumption in the oil and gas industry will have a significant impact on reducing global greenhouse gas emissions.
For offshore oil and gas operations, a major power consumer is rotating equipment to add energy to the system, either for transporting fluids or increasing recovery factors. Some sort of artificial lift is often required to maintain production from a reservoir because the reservoir pressure drops due to depletion and water cut increases over time. Artificial lift with rotating equipment is a major contributor to CO2 emissions in oil extraction. A main challenge is maintaining production profitability while reducing the emission intensity and thereby the environmental footprint.
This paper explores the energy efficiency and CO2 emission impacts of different artificial lift methods, particularly multiphase boosting technology and gas lift technology, which are both mature and field proven.
A generic field model was developed to analyze the energy consumption using different improved oil recovery (IOR) technologies in gas lift and multiphase boosting. A power ratio between the two lifting techniques was defined for a clear comparison. The CO2 emission and enhanced production effects were analyzed for a range of tieback distances (5-50 km), water depths (50-1,000 m) and different number of wells. Sensitivities with regards to water cuts, separator pressure, and compressor discharge pressure are also discussed.
The study suggested that energy efficiency is dependent on field layout and that the CO2 footprint can be significantly reduced with an optimum artificial lift method.
The United Nations has adopted a set of sustainable development goals (SDGs) for attainment by 2030. Agencies such as IPIECA have outlined how oil and gas industry contributes to SDGs /2/, one of the big contributions is in energy efficiency, which is related to power consumption as well as gas flaring. The IEA estimated that 46% percent of CO2 emission savings would come from end-use efficiency compared with 17% from renewable energy /3/.
