Riserless Well Intervention System

The Riserless Well Intervention System (RWIS) is a modular system designed for safe and efficient subsea well access, deployed from a dynamically positioned monohull vessel. It features a 7 3/8" bore and a maximum working pressure rating of 10,000 psi, allowing access to conventional and horizontal Christmas trees in water depths up to 2,200m.

The RWIS comprises a Well Control Package (WCP) as the primary well control safety system. The WCP is a lightweight system (42T) with dual isolation ball valves that can fail-close automatically using stored hydraulic fluid during emergencies. It includes a Shear Seal Gate Valve (SSGV) capable of shearing and sealing against tool strings like wireline or slickline tools up to 22m long.

The modular lubricator riser supports these long tool strings, and a bore selector can provide mechanical access to the annulus. Additional modules like a re-entry module for placing production barriers or a temporary abandonment plug spool enable various intervention and abandonment operations.

The RWIS's unique SSGV design requires significantly less control fluid than conventional systems, reducing the need for subsea accumulators and overall weight. Its modular design offers operational flexibility, enabling access to aging subsea trees, production enhancements, well integrity operations, and plug and abandonment activities from a single supplier.