Industrialisation of SPRINGS®, A Qualified Subsea Sea Water Desulfation Process

Abstract

SPRINGS® (Subsea PRocessing and INjection Gear for Seawater) is a qualified process for subsea water treatment and injection. It uses membrane technology for water desulfation upstream of water injection wells to prevent sulfate scaling on the production side (nearwell bore, well and production equipment). It moves the water treatment from topside to subsea locations close to the injection wells with only power and communication tie-backs to existing topside facilities. Qualification of the process was achieved through both onshore and offshore trials. In advance of deploying the first industrial application, an industrialisation programme was undertaken in order to ensure that every component necessary for the subsea process implementation was available and had a sufficient technology readiness level to be safely installed and operated within the subsea plant. The existing and available technologies were reviewed vis-À-vis the requirements arising from both the process and the business strategy. Several industrial partners were engaged to determine the elements of novelty that needed to be brought to each technology or component to satisfy such requirements. The new technologies included: Subsea barrier-fluidless pumps Open framework all-electric control systems High-cycling electric actuators and valves Subsea water analyser Subsea storage and injection units for chemicals The design basis for the development of each technology, which in most cases included the realisation of a prototype and relevant qualification testing, was set up to consider a range of possible applications with differing environmental conditions, process data and/or IMR scenarios. The most challenging conditions were selected for each development to determine the relevant required performance. Where available, specific standards, such as API 17F (ref. [8]) for subsea electronics, were followed to determine the qualification plans. In those cases where no dedicated specific standard was available, the evaluation of the proposed solution was performed in conjunction with the technology provider through the risk based approach stated in API 17N (ref. [9]) and DNV A203 (ref. [10]). Failure Modes, Effects and Criticality Analyses (FMECAs) as well as technology readiness assessments were performed in order to develop the technology qualification plans. Most of the key equipment qualification plans will be completed by mid-2019, establishing an industrial platform for the deployment of the subsea water treatment and injection technology in a completely all-electric configuration, i.e. connected to the surface only through a communication and power cable. Such an industrial platform will also contain the building blocks for other subsea processes. The presentation and paper will introduce the elements of technological novelty and will describe the process, the challenges and the results of the relevant qualifications.