eSubsea provide detail design, engineering, procurement and construction EPC of subsea riser bases with or without SSIV (subsea isolation valve). The riser base manifold (RB) is a subsea structure that connect the flowline or pipeline with the flexible riser. The subsea connection system can be horizontal or vertical and the large bore piping normally incorporate one or more ROV or hydraulic operated isolation valves. These could also be SSIV fail-safe closed isolation valves.

The subsea structures will be design for all relevant loads such as installation lifting to dropped object. The riser base manifold and SSIV valve is most often within the fishing exclusion zone of the host facility and do not need an overtrawlable or fishing friendly design.

Subsea Riser Base and SSIV
Do you have a Riser Base or SSIV project and need help? Contact us for more information!

Riser Base Foundation Structure

The riser base foundation structure will be designed based on the soil conditions. In sand and hard clay, the foundation could be by mudmats and gravity-based stability. In softer clay, the foundation could be by using one or more suction anchors or suction buckets.

Concept-Level Screening Before Full Design
Screen Your Riser Base or SSIV Structure Before Committing to Full EPC
Riser base and SSIV structures are typically compact but carry high structural demands — riser loads, pipeline thermal expansion forces, valve reaction loads and dynamic fatigue from wave and current induced motion all need to be considered. Getting the structural scheme right at concept stage avoids costly redesign when detailed engineering begins.

esubsea.ai can rapidly screen a riser base or SSIV concept across the critical engineering disciplines, giving you reliable preliminary outputs to base your scope and budget decisions on:
  • Structural frame: member sizing and code checks per NORSOK N-004 under riser, piping and environmental loads
  • Foundation: mudmat bearing capacity and sliding resistance per ISO 19901-4
  • Piping: large bore pipe wall thickness and flexibility assessment per ASME B31.8
  • Lifting analysis: installation lift point and rigging geometry per DNV-ST-E273
  • Cathodic protection: anode sizing per DNV-RP-B401
Typical saving: Riser base and SSIV concept screening via esubsea.ai delivers reliable preliminary results at a fraction of the cost of a full EPC study — enabling informed decisions on structural scheme, installation method and fabrication budget before full engineering commitment. Full detailed design and signed documentation available when required.

Subsea Isolation SSIV Valve

There are several manufacturers of SSIV subsea isolation valves which can be integrated in the riser base to create a safety barrier to protect the environment and personnel on the rig, floater or platform from accidental release of gas or hydrocarbons. The valve has a high reliability and safety rating, normally to SIL 2.

Riser base and SSIV Control System

The hydraulic operated actuators on the subsea isolation valve will be control from an umbilical from either the subsea production system terminated close to the foundation structure or be an integrated part of a subsea umbilical riser base structure. If terminated separately, electrical and hydraulic jumpers a or flying leads will be used to connect the control system with the umbilical termination.

Start with a Concept Study

eSubsea with its engineering partners can carry out concept and feasibility studies which include concept evaluation, preliminary engineering and design, drawings, P&ID, SSIV safety and protection philosophy, subsea connection system, weight, structural analysis and pipe stress analysis sizing based on company requirements and required codes and standards. The concept study is a cost effective way to quickly establish the RB size, weight, budget cost and delivery schedule.

Translate this page to Norwegian – Stigerørsbase and Sikkerhetsventiler