Challenges and Opportunities for Subsea Multiphase Boosting Application

The Campos Basin is a prolific oil-producing region in southeastern Brazil, with reservoirs and fluids of great variety. Although pumping has been employed to enhance the production of accumulations located at shallow depths, gas lift has established itself as the main method of artificial lift in production development projects, largely due to its simplicity in design and operation, as well as its robustness and flexibility for use in different fluid and reservoir scenarios. With the advent of pre-salt discoveries and the consolidation of the Santos Basin as Brazil's main producing region, a preference for gas lift has again been observed for the implementation of new projects—although the variation in oil properties is much smaller, the high productivity and elevated gas fraction, due to the higher solubility ratio combined with gas injection for secondary recovery, have reduced the attractiveness of alternatives using other artificial lift methods. However, decades after the initial production developments, the scenario appears somewhat different. Infilling projects need to technically and economically enable opportunities with less favorable petrophysical characteristics, sometimes in regions that have already been previously washed and almost always with large offsets, making pressure loss management in the system and flow assurance critical. In this new scenario, pumping, capable of providing hydraulic power directly to the fluid with increased flow rate or favoring lower heat transfer loss to the subsea environment, is reborn as a competitive option, highlighting the challenges for both new and existing production systems. This paper will address the technical challenges due to specificities of Petrobras, a Brazilian mixed-economy company with rigid processes shaped by specific legislation for acquisitions. Two case studies in which the selective application of subsea multiphase pumping, combined with gas lift injection in the production column, proved to be the best economic alternative, adhering to technical design guidelines, will be displayed as examples.