New local subsea processing systems will need to be developed to allow remotely located satellite oil fields to be produced economically. One such system treats seawater for injection into the reservoir.
As reservoir waters often contain elevated concentrations of barium or calcium, treatment systems need membranes to remove any sulfates that may form in the seawater before it is injected into the reservoir, in order to avoid severe scaling.
SPRINGS (Subsea PRocess and INjection Gear for Seawater) is a collaboration project between Total, Saipem, Veolia Water and VWS Westgarth. It was initiated in 2007 and aims to provide robust solutions featuring the use of membranes for treating seawater on the sea bed in deepwater areas.
SPRINGS has now reached qualification stage and a first industrial application is planned for 2015.
This paper describes the SPRINGS development project, including an update on the latest progress to date. It presents a specific case study conducted in the Gulf of Guinea which illustrates the commercial and technological advantages, along with the limitations, of deploying this technology for future remote applications.
It compares the conventional field architecture utilized in conjunction with water injection from FPSO topsides with the architecture required for a SPRINGS solution on the ocean floor.
The information provided allows operators to consider an alternative development strategy for the application of membranes to water injection in remote satellite fields.
The development of isolated subsea fields, far from existing production centres or from the shore, and sometimes in very harsh environments such as deep offshore, West of Shetlands or the Arctic seas, has led Total E&P to develop new building blocks of innovative subsea processing.
One block required for the development of subsea oilfields is the treatment of seawater for injection (sometimes going as far as desulfation, if the reservoir water contains significant levels of barium or calcium), to maintain pressure and optimize recovery of reserves.