Seawater as Offshore Water Supply

Not all offshore platforms are manned. But depending on the tasks to do personal can be needed on these platforms or a FPSO (Floating Production Storage and Offloading Unit). No matter if the personnel is constantly stationed or only their stay is limited in time – fresh and drinking water is needed.

Freshwater on offshore platforms is also necessary for technical purposes such as cooling or to produce steam in the processes.

The water needs to be produced on the platform. It is not possible to deliver fresh water from onshore. Using seawater to generate fresh water involves some technical problems. It is highly corrosive, there is a high amount of minerals solved, causing scaling and especially in warm environment, biological growth can affect the water system.

Seawater is as well used to pressurize the reservoir. Not only on offshore platforms but also onshore, where the fresh water supply is not sufficient. Therefore water is taken from the sea and often pumped through injection wells into the reservoir untreated. In these pipes corrosion and deposition cause problems. The seawater also aggravates the corrosion by SRB (Sulfur-reducing bacteria).

Our experiences in this business segment started with equipping 20 platforms in the Far East. There we have been taking care of the whole water system from seawater to freshwater and its usage. The system includes pumps to lead the seawater on the platform, compressors, coolers, the drinking water supply and much more. We installed directly after the seawater-pump and thus were able to bring corrosion under control. Subsequently, problems with leaking and brown water were reduced significantly.

Before our installation, critical pipes had to be replaced regularly due to leaking or blocking. In some cases, a pipe section didn’t even work for one single year. The damage is not limited to pipes but also affects the machinery or process units.

The Merus Technology was able to reduce the corrosion rate by up to 90% which is also increasing the lifetime of the equipment. A quick calculation reveals possible savings of Millions of Dollars per year. Only reducing shutdowns and maintenance time due to malfunctions or service stabilizes processes around the fresh water. Not only in terms of drinking but also for cooling, etc..