An underwater balloon defending the sea: OIE designed by Saipem

Uncontrolled blowout of subsea wells is a threat that has caused a number of environmental crises in the past. The tragedy that happened in 2010 in the Gulf of Mexico with the explosion of the Deepwater Horizon platform represents a decisive watershed in the identification of effective countermeasures.

In the aftermath of the Macondo incident, the International Association of Oil and Gas Producers established a Committee called the Global Industry Response Group. The Committee brought together more than 100 technical experts from 20 companies around the world. They worked together to identify, learn from and apply the lessons of Macondo and similar well control incidents, developing recommendations to improve well incident prevention, intervention and response capability.

However, soon several studies showed that installing these Capping Stacks at medium-low depths (from 75 to 600m) would be challenging. Working at medium-low depths is a very common scenario and in these situations these studies showed that it is not possible to operate safely with a vessel vertically above the well (method used to seal the Macondo’s oil spill). In case of oil spill at medium-low depths in fact the surface of the sea is often covered by hydrocarbons. Such a situation could generate potential fires while causing stability problems for vessels making almost impossible a safe and quick intervention. In order to solve this problem in 2011 Subsea Well Response Project launched an international call for projects to identify the best technological solution. Saipem won the contest presenting the Offset Installation Equipment (OIE), a unique system based on the latest submarine robotic technologies. With OIE it is now possible to install the Capping Stacks while safely keeping vessels 1 km away from the incident. Oil Spill Response owns the device and mobilises in the event of an incident. Saipem stores and maintains OIE always ready for action.

Between Trieste and Marghera (Venice) Saipem opened an international hub focusing on subsea robotic technologies where it is testing and developing innovative robotic solutions. After 6 years, over 200 engineers and specialized personnel have been involved, 4000 drawings and documents have been produced, half a million hours have been worked and a production chain comprised of over 150 companies (in large part Italian) OIE has finally come to life.

The main element of the OIE intervention system is the Carrier, a sort of underwater balloon weighing approximately 250t, remotely controlled by a robot (ROV) capable of aligning the Capping Stack with a precision of millimetres while the well is still discharging oil. OIE's Trained personnel safely control the Carrier from a vessel located 1 km away from the incident zone. The Carrier mainly consists of 4 tanks which can be filled with air to generate a net variable positive up to 150t. This characteristic allows safe transportation of the Capping Stack and the materials necessary to operate on the well through the incident zone. The Carrier stands 14 m in height, is 11 m wide and is 13 m long. It includes over 120 remote executions and more than 200 sensors that enable its functioning also in extreme environments.