Sorting Subsea Seawater Injection

As oil fields mature, oil production rates decline. Water injection, to either help maintain reservoir pressure or to help sweep more oil from the reservoir, is an established method to maintain production rates and the requirements for water injection are expected to grow year-over-year.

But it’s not as simple as just pumping available water, such as seawater, down into specifically drilled injection wells. The water must be treated to be disinfected, remove particles and sometimes adjust the chemistry of the water, which can mean having to remove sulfate and reducing salinity levels.

For mature offshore facilities, adding or even increasing water treatment and injection facilities can prove difficult, due to space or weight constraints, and may also be prohibitively expensive. While it’s possible to inject water into subsea wells, subsea water treatment technology has not been available until now, which means topsides facilities have been needed. This makes water injection expensive for long-distance tiebacks, due to the high-pressure pipelines and pumping equipment that would be needed.

By introducing subsea seawater treatment, topsides water treatment and pumping equipment, as well as long, high-pressure pipelines, would no longer be needed.

NOV, through its Seabox business in Norway, is paving the way.