Multiphase Pump Solution Deployed in World’s Deepest Subsea Heavy Oil Field
Chris Carpenter_
This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 36841, “Atlanta: Boosting the World’s Deepest Subsea Heavy Oil Field,” by Marcelo Paulino and Henrique S. Cerqueira, SPE, Brava Energia, and Christophe Vielliard, SPE, SLB OneSubsea, et al. The paper has not been peer-reviewed. Copyright 2026 Offshore Technology Conference.
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The Atlanta Field is the world’s deepest subsea heavy oil development, producing 14° API crude with a viscosity of 250 cp at reservoir conditions. This paper details the design and implementation of the subsea multiphase pump solution that was deployed in Atlanta, including system design for high-viscosity boosting and engineering solutions to maximize reuse of existing subsea and topside equipment. This was key to ensure reliable, cost‑effective production.
Introduction
The Atlanta development was divided into two phases: an early production system (EPS) that entered operation in May 2018, and a full‑field development (FFD) that began in December 2024. The EPS was developed with a satellite well architecture, wherein each production well is tied back directly to a floating production, storage, and offloading vessel (FPSO) through a dedicated flowline and riser plus a dedicated electrohydraulic umbilical and one service line. The subsea tree thus required limited functionality, because production control is performed through a topside choke and flowmetering is achieved during periodic well tests through a topside test separator. This enabled an integrated approach comprising operational insights from the EPS combined with vendor expertise.
Phase 1 of the Atlanta FFD comprises six wells, four of which have produced during the EPS and two wells newly drilled for the FFD. Based on the operating experience from the EPS, which consisted of in-well electric submersible pumps (ESPs) and horizontal seabed ESPs as a backup, the artificial lift method chosen for the FFD was subsea multiphase pumps (MPPs). This change in boosting technology required creative engineering solutions to work within existing infrastructure constraints, reusing topside systems, umbilicals, and trees that lacked subsea choking and metering capabilities. This approach has a significant effect in reducing the cost and carbon footprint of subsea development.
System Design
The subsea pump-station design included the following adaptations to enable implementation within the constraints of the existing equipment:
- Existing subsea horizontal trees without flowmetering and flow-control functionality
- Existing 6-in. flexible production flowlines
- Existing power and control umbilicals with 150 mm2 medium-voltage (MV) power cables and existing topside variable speed drives (VSDs) sized for ESPs
Subsea Station Design.
The pump-station functionality includes the following key features:
- Multiphase flowmeter and production choke valve on each inlet
- Commingling of production from two wells
- Boosting of two wells with a single MPP
- Flow splitting downstream of the pump, producing through up to two 6-in. flexible flowlines and risers
This arrangement allows for the boosting of the commingled production from two wells by incorporating the flowmetering and flow‑ control functionality that is not available on the existing X‑trees.