Subsea water removal has emerged as a viable option to prolong the lifetime of brown field installations, increase recovery and generate increased return for operators. This paper presents a thorough literature review of both current subsea liquid-liquid separation installations as well as state of the art technologies currently being developed for field application. The applicability of respective technologies to identified business cases is discussed, including principle of operation, size and efficiency considerations, as well as technology readiness level. The details and layout of a newly constructed oil-water test loop to develop and design compact separators will also be presented.
During an oil field's operational lifetime, the quantities of produced water in the production stream will steadily increase. Eventually, produced water will emerge as the main extracted fluid, and the rate will steadily increase until production is no longer economically viable. A review of oil and gas produced water treatment from 2009 (1) reported a global produced water production of 250 million barrels per day, accounting to a produced water to hydrocarbon ratio of 3:1. Looking to the NCS (Norwegian Continental Shelf), a total produced water quantity of 190 million m3 was reported for 2015, accounting for more than twice the amount of produced oil (2). This ratio will steadily increase as more fields are reaching their mature stage, and illustrates the need for produced water management.