The Shell operated BC-10 field located in deepwater, 1650-1920m (5500’-6400’), offshore Brazil produces heavy oil in the range of API 16-24. Due to the low reservoir energy and deep water environment, 100% of BC-10 production has artificial lift. Mudline caisson separators with ESPs (Electrical Submersible Pumps) are used to process fluids from multiple wells and boost them to the receiving FPSO. These caissons are 80-100m (260’-330’) deep and each houses a 1600HP pump. The 4 distinct fields are located approximately 8-14km from the producing FPSO and there are significant flow assurance challenges in operating the asset. Over the past 5 years, production optimizations have been trialed and implemented – some successful, some not. In this paper several examples will be given of production optimization which has resulted in increased throughput of the system without mechanical modifications, reduced OPEX on chemicals and taken advantage of natural changes in fluid properties as the field has aged. The optimizations included; caisson foam management to enhance flowline lift, subsea demulsifier injection for viscosity reduction and alterations to gas-liquid subsea separation to achieve high and low GOR operation.

Through these optimizations, it is estimated that 2MM bbl additional volumes were produced in 2013-2014 together with a $4MM US/year reduction in chemical usage. The enabling factors for these optimizations will be examined in relation to system design and surveillance.

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