As a specialist in mature fields, Perenco is particularly concerned by the decommissioning of its oil platforms. These operations raise logistical, environmental and economic challenges. Perenco is faithful to its logic of integrating know-how, so the company has already developed the essential skills required for decommissioning and completed several decommissioning operations in the North Sea.

A new industry

The decommissioning of oil facilities consists of returning a site to its original state prior to drilling and constructing the operating structure. The shutdown of an installation when unavoidable at the end of the economic production of its reserves, is therefore an important decision. It involves both the operator and the relevant State. Many prior studies and steps are undertaken to validate the relevance of a decommissioning operation.

A decommissioning project takes place over several years and requires the mobilisation of significant logistical, financial and administrative resources. The project begins with prospective studies to consider various solutions that may lead to eventually recycling the site.

In some cases, costs can be minimised by reusing platforms as artificial reefs, weather stations, research centres, energy production sites and CO2 storage sites, etc. Perenco sees decommissioning as a true opportunity to reinvent and develop its business and to value its innovative skills.

At Perenco our job is first and foremost to sustain resources and thereby to extend the life of mature sites. The first field operated by Perenco under its current form was Oguendjo, bought back in 1992. In 2018 this field still produces 1,500 barrels per day – and it should keep producing for another 20 years !

A real challenge for the industry

When we deal with a decommissioning project we discover a very old platform, often built by a third party operator with hardly any documented standards that can date back to the 1960s’. The first step is to analyse the entire installation. This audit phase allows us to define specifications and validate operation costs.

This goes hand in hand with an analysis of local regulations and an environmental impact study to define the final perimeter of the works to be undertaken with the authorities. Apart from finding alternative ideas to re-use the facilities, decommissioning can at times be more destructive for the environment that already in-situ solution, so we must study each specific case individually.

We start the operational phase by permanently cementing the well and completely sealing it. Then, we proceed to the cleaning of all facilities that were used in the process and to the removal of hydrocarbons, so that we do not contaminate the environment. This step can last several months. Finally we proceed to the most spectacular stage: the removal of the platform. All installations are transported on land for final treatment either for reuse elsewhere, or for recycling according to the environmental rules of the relevant country.

From the first decommissioning projects, Perenco immediately chose to integrate all the resources, technologies and skills required. In a very new market with hardly any references, the company had to deploy all its know-how in engineering, create new processes, explore administrative procedures - especially regarding permits- and find suitable partners; all while carefully controlling costs. Our oil expertise and agile operating methods have indeed brought real benefits.

A technical and economic challenge

At Perenco we approach decommissioning as exploitation, with the same rigor and the same ingenuity, to develop the tools most suited to our operations. We do not proceed by reverse engineering. From the beginning we made the choice to disassemble and remove platforms in parts to avoid chartering very expensive boats. Instead of carrying 5,000 tons at a time, we proceeded in two or three loads. Similarly, we do not use rigs to cement the wells. We deploy more flexible and lighter technologies. This is how Perenco innovates.

Such alternative choices make it possible to service projects in accordance with State regulations. For example, the United Kingdom mandates oversight bodies (OGA, BEIS, etc.) to ensure that decommissioning is carried out in a safe, environmentally sound and cost-effective manner.

An activity for the future

Decommissioning represents a real challenge for the future as more and more fields will be affected. Perenco has made its reputation and success by challenging exploitation on marginal wells where larger companies are not as efficient. 
Decommissioning is for Perenco a new opportunity to develop its know-how, to show its capacity to create value and to perfect coherence with the founding spirit of the company, i.e. to create alternative, innovative and cost-effective models.

Integrating the decommissioning activity also represents a real opportunity for employees who are looking for technological challenges with an environmental scope. Drilling engineers, project or production engineers are involved.

Our decommissioning achievements in the North Sea

Perenco is a globally recognised company, able to work anywhere in the world. Since 2003, Perenco has been present in the North Sea, where four decommissioning projects have been undertaken, out of which two are still in progress: Welland (2010-2016), Thames (2013 -2018), Tyne (started in 2016) and more recently Guinevere.

Perenco has operated in compliance with all applying rules and costs, from preparation stage to operational realisation and liquidation, and with all the necessary documentation as well.

A key component of Perenco’s success since its creation has been to personally operate its own assets. Tomorrow, our success will also partly depend on the company’s ability to decommission them.

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PERENCO Decommissioning oil rigs

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