Arrangement and method for protecting components in subsea systems

Arrangement for protecting components incorporated in subsea systems particularly for hydrocarbon production, comprising:

• A plurality of functional modules for containing at least one of the components, adapted to be retrieved to the surface;
• a subsea template structure adapted to rest on the sea bed, provided with supporting members supporting the plurality of functional modules;
• each of the functional modules being provided with roof elements, including at least one fixed roof element along at least one side of the module, and a removable roof element covering a central portion of the top area of the module, the central portion being adapted to be recovered by a module running tool during installation and retrieval operations;
• The roof elements of at least one module further including at least one smaller roof element for covering components arranged for cooperation with a module running tool, provided with locking means to be operated by the module running tool, for securing the smaller roof element in position on the module;
• the fixed and removable roof elements together covering substantially the entire top area of the module, and the roof elements of all modules in the subsea structure together covering a major portion of the top area of the subsea structure, to protect against objects falling from above or moving along the sea bed;
• the roof elements having a deformability adapted to be permanently deformed or crushed when a falling object results in an impact force thereon exceeding a predetermined threshold value;
• the fixed roof element of each module being adapted along an edge portion to form a support for the removable roof element of each module;
• the deformability of the removable roof elements being higher than the deformability of the fixed roof elements, whereby a sufficiently large impact force from a falling object on the removable roof element will lead to a stepwise deformation first of the removable roof element and then of the fixed roof element;
• a load from the roof elements of the modules being transferred to the supporting members of the template structure through the modules;
• and
• the roof elements of all modules lying substantially in a common plane without any significant part of the subsea structure protruding above the roof elements.

A method of protecting components in subsea systems, comprising:

• levelling and securing a template to a seabed;
• installing a module into the template;
• unlocking and retrieving a removable roof element from the module;
• unlocking and retrieving a component from the module;
• and
• protecting the module with a fixed roof element during the unlocking and retrieving steps.