How the decommissioning of oil rigs is done

  • 05/03/2020
  • 11 minutes

“Decommissioning” is a word that gained relevance in recent years. Understand now the importance of platform decommissioning and how it is being done.

Returning something to its natural state is one of the explanations for this word that’s being constantly reproduced in the news. Given the risks that all infrastructure offers, decommissioning has become a smart and viable option in many segments.

In order to better understand the term, we first need to explain its history: the installation of offshore platforms in the oil and gas market began in the 1960s. At that time, it was common to install fixed platforms with structures embedded in the seabed, according to Wilson Sons’ market intelligence expert Karla Brazil.

She adds: “In this way, their demobilization is much more complicated than the Floating Production Storage and Offloading (FPSO) that are the most used today.”

Many of these structures, addding up to over 70 years old, featured old systems that needed expensive maintenance. Without the same level of productivity and efficiency compared to the newer ones (which have more technology coupled with them), older platforms now represent more expenses than gains.

“In addition, it should also be mentioned that these platforms are in old production fields, which have been in service for a long time, with oil and gas reserves running out and a considerable decline in production year after year.” , completes Karla.

In short, old and obsolete structures generate large maintenance costs without financial return due to low productivity, which is a determining factor for decommissioning platforms. So what is decommissioning and how is it done? That’s what we’ll see next.

Platform decommissioning

The term is defined by the National Petroleum Agency (ANP) as follows: “Decommissioning is the set of legal actions, technical and engineering procedures applied in an integrated manner to an Offshore system to ensure that its decommissioning or cessation of production meets the conditions of safety, environmental preservation, reliability, and traceability of information and documents”.

Would it be a return to the original condition?, one might ask. “This means that, at the end of the field’s production cycle, the facilities must be dismantled and the area occupied must be returned to its original condition, as established by the Law No. 9,478 of August 6, 1997, the Petroleum Law”, explains the expert on the subject Taciana Amar, from Amar, Fróes & Ferraz Advogados.

It is estimated that, by 2020, the decommissioning of a number ranging from 15 to 20 platforms will start. Of the 150 platforms in Brazilian waters, 79 are already in the initial decommissioning phase or ready to begin.

“The shelf life of a platform is 20 to 25 years,” reports Taciana. “However, more than 50% of the production units in Brazil have already passed 25 years of operation, which requires human effort and also operation, material, logistics, financial, among other efforts, so that these production systems can continue producing in a way that’s economically viable, safe, and environmentally sustainable by the end of the concession period”, she warns.

But there are cases in which such sets of actions allow the production system to be able to produce beyond the concession period initially contracted with the ANP. “In this case, the operator should ask the regulator for an extension of the concession period”, says Taciana.

It should be noted that the market view is that the real need for decommissioning only occurs when, after studies and technical and economic analyzes, it is verified that there are no more possibilities for revitalization of the production field.

“Petrobras has been doing this by selling some old production fields. Thus, the new operating companies have the responsibility to invest in the revitalization of the fields through new wells and technologies to increase the production level and to postpone the need to decommission the platforms as much as possible”, reports Karla Brazil.

A long process, with many involved

The decommissioning project of a platform involves a number of professionals working in the areas, such as civil, maritime, and marine engineers, as well as project management, topography, professionals in various areas dedicated to the environment, waste management, recycling, catering, and maritime support.

On average, decommissioning a productive system takes, on average, from the moment of its decision until the total devastation of the area, around 10 years, “precisely because it is a very complex process, which requires practically the same number of people working until the total withdrawal is complete”, details Taciana.

“The decommissioning of fixed platforms can be by complete removal, partial removal, or tipping”, explains Karla Brazil. Prior planning and studies are required for selection: inventory, inspection, volume/weight determination, procedure definition, and risk analysis. Only then does the decommissioning process actually begin. Karla specifies each of these processes below:

  • complete removal: process that’s the reverse of the installation, the entire structure is removed and, for this, it can be cut into several parts for transportation. Barges and tugs should be used for this purpose;
  • partial removal: removal of only part of the structure from above to the appropriate level, according to a previous study. The removed part can be transported to land or disposed of at sea. Normally, it occurs because an ecosystem was created in the submerged part that would die with its removal;
  • tipping: the entire structure is tipped in the same place. For this, explosives are used for the purpose of sectioning the platform — tugboats are a common need in this case.

Decommissioning practice and legislation in Brazil

Decommissioning has been practiced in many countries for at least two decades in a more organized way. However, in Brazil, although some decommissioning has already been done — only on floating platforms —, discussions on the topic are recent on the agenda of operators, civil society, companies, regulators, and universities.

All of this is marching to discover the best practices that can be verified around the world. “We need to find the most successful regulations and laws in the country and finally create a modern regulation that adheres to our reality, shaped by our characteristics and to a continental country”, suggests Taciana.

She continues: “To understand the importance of such an agenda for the country, this is the first time a regulation has been written with such engagement with the Navy/IBAMA/ANP.” This regulation should be released at the end of the year and is a review of the ANP regulation 27/2006, the only one that until then regulated decommissioning activities in the country — a big step that gives more clarity to the subject.

Issues faced by environmentalists

Decommissioning can sometimes involve unimaginable issues. “One of the biggest problems faced by environmentalists is the existence of an exotic and bioinvasive species called Coral-Sol”, recalls Taciana.

The species has no natural predators in the country and destroys the native coral fauna. The situation is all the more worrying because their larvae breed when there’s an attempt to mechanically remove them from underwater structures, thus multiplying. All this makes the species difficult to eradicate, which makes the situation even more challenging.

Prospects for the future of decommissioning in Brazil

According to Taciana Amar, by 2025, 20 decommissioning processes should be carried out. For her, the work of decommissioning platforms is inevitable and may also inspire some initiatives. “I hope it forms a supply chain of goods and services in Brazil and that we jump into this business opportunity, learn by doing,” she concludes.

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