eSubsea provide detail design, engineering, procurement and construction EPC of subsea riser bases with or without SSIV (subsea isolation valve). The riser base (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 and SSIV is most often within the fishing exclusion zone of the host facility and do not need an overtrawlable or fishing friendly design.
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.
Subsea Isolation Valve SSIV
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.