Case Study: Upgrading Gravity Water Deoiling Separators with Hybrid Deoiling Technology for Enhanced Performance and Reduced Carbon Footprint

Abstract

Abstract Objective/Scope Increase in water-cuts is a common occurrence in oil fields in which water flooding is used for secondary oil recovery. Managing cost of water handling is one of the primary challenges as it continues to erode the profitability. Furthermore, increasing energy requirements to reinject or dispose of the water leads to additional carbon dioxide emissions. More efficient processes are needed to reduce CAPEX & OPEX and reduce carbon emissions. Methods, Procedures, Process In anticipation of water rates exceeding facility produced water deoiling capacity, Saudi Aramco upgraded an existing gravity water-oil separator with a hybrid process that combines enhanced gravity separation and induced gas flotation (IGF) in one vessel. The feed water enters a gravity section with plate packs as a primary deoiling process. Water with less oil from the gravity separator then feeds an IGF system within the same vessel to reduce the oil-in-water even further. Deoiled water is then degassed in a quiescent section before being discharged to the injection pumps. Results, Observations, Conclusions Deoiling capacity was implemented at 40% of the cost of a conventional processes. After the retrofit, the deoiling capacity increased by 50% and the outlet oil-in-water was reduced by 65%. Significant capital expenditure savings were realized as it eliminated the need to install additional vessels for increasing gravity separation capacity. Furthermore, it eliminated the need for installing a separate induced gas flotation system. Additionally, stable water flow from the separator resulted in reducing energy consumption by 15% as the downstream water injection pumps do not need to recycle due to dips in feed flow caused by severe fluctuations in rate. Energy savings reduces costs and carbon emissions. Improved water quality means more oil is recovered which translates to additional revenue. Some lessons learned were gained, including adjustments to start-up procedures and the ideal control setup to ensure a smooth and stable process. Novel Information The hybrid solution process can achieve the desired capacity and water quality with less footprint and enhanced process control. The project offers several design and operations best practice of this hybrid system. Since it has been commissioned in July 2022, Saudi Aramco has both increased capacity and quality of the water. Furthermore, water flow to the injection rate has been more energy efficient due to less recycling.