The increasing demand to plug & abandon (P&A) subsea wells has reinforced the need to identify true opportunities to reduce the costs of subsea abandonment.

The existing method in typical P&A programs of switching from a light well intervention vessel (LWIV or dedicated intervention semi-submersible) after lower abandonment, to a drilling rig with subsea BOP and drilling riser to perform upper abandonment activities is uneconomical, due the loss of efficiency and increase of total operational time.

In 2016, a project to develop an 18 ¾" large bore Riserless Open-Water Abandonment Module (ROAM) was launched to enhance well abandonment capacity from a well intervention vessel, by allowing tubing to be pulled in open water in a safe and environmentally contained manner. The ROAM is run in combination with a high pressure Intervention Riser System (IRS)

As ROAM has circulation capability and is self-contained, once the tubing hanger is unseated, residual fluids and debris can be flowed back through circulation hoses and the IRS intervention riser system to the LWIV, guaranteeing minimal leakage to the environment during tubing pulling operations.

ROAM also allows operator to check integrity of the cement bond behind the casing through a logging run after production tubing removal. According to the results, operator can decide to move on with upper cement plug placement and conclude the P&A or safely leave the well and prepare the remedial operation. The full bore access afforded by ROAM opens up multiple options for ‘abandonment in situ’ operations to be performed.

In order to keep the well safe in the event of the vessel losing its position (through drift-off or drive-off), ROAM has dual 10,000 psi rated shear-seal rams, an emergency quick disconnect (EQD) system and a stand-alone intervention work over control System (IWOCS), as well as a 10,000 ram to isolate annulus/circulation side.

ROAM, combined with existing riser-based (IRS) and riser less intervention systems (Subsea Intervention Lubricator or SIL), will extend the capability of well intervention vessels to perform a full P&A without jeopardizing well control and environmental protection.

The paper will give a detailed description of the design, capabilities and operational premises considered in ROAM development and also demonstrate how the system is deployed and operated to guarantee a safe, efficient and cost-effective operation. The paper will also detail all the executed qualifications and performed tests, as well as the update about manufacturing and field-tests.

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