Deepwater ROV and Tools 

Offshore field development in deep waters, typically involves the use of floating production supports in combination with flowline networks, subsea wells and manifolds. Such development scheme requires numerous subsea interventions that are out of the reach of the direct human intervention, thus putting demands on the remote subsea intervention means, such as Remotely Operated Vehicle (ROV), role and reliability to a high level.

ROV's were introduced offshore in the early 80's, as an observation and safety means for divers during their underwater interventions. With the acceptance of these new tools by the offshore industry, these remotely operated robots were further equipped with arms (i.e. manipulators) to perform more meaningful works than just observation tasks.

At the same period deeper water explorations at 300 - 500 meters were being contemplated (mainly in the North Sea and in Brazil), and it is the drilling industry who provided the ROV industry with the unique opportunity for further development. The incentives were twofold: (1) ROV's are more cost effective than manned intervention (e.g. saturation diving systems, submarines, one atmosphere bells) and (2) safer operation as humans were not required in the hostile underwater environment.

With commercial diving limited by water depths (e.g. 180 - 200 meters in North Sea and around 350 meters in Brazil), the ROV ability to work at extreme depths make it an essential tool for the offshore deepwater exploration and production: ROV's are the "eyes and the arms" of the offshore construction personnel.

This document is the Fifth edition (1^st edition September 1999) and will review the current state of the art in remote subsea intervention technology, its capabilities and the deepwater operations requirements, such as:

Remote subsea intervention effectiveness lay firstly with the defined intervention philosophy (refer to Section ), followed by the evaluation of the interface requirement and impact on the SPS equipment and surface support vessel designs (see Section ).

Section is dedicated to the general description of ROV systems and the main technical characteristics for different ROV vehicles (i.e. Drilling ROV, Construction ROV, Survey ROV).

The developing technology of Autonomous Underwater Vehicle (AUV) is described in Section , including both the survey and intervention activities.

Once the subsea tasks to be performed have been identified, the next phase is to establish the intervention method. There are two primary methods of remote intervention on subsea production systems (in addition to AUV current capabilities): intervention by Remotely Operated Tools (Section – ROT) and intervention by tools mounted onto the ROV structure as further detailed in Section , ROV Tools.

The technical characteristics of the available deepwater ROVs and the list and addresses of the main ROV Contractors and Manufacturers provided in the annexes will conclude this document.

This study is based on the following sources:

We wish to thank the installation contractors and vessel owners for the provision of technical information and photographs of their ships, installation vessels and products.