Decommissioning of Oil Platforms Requires Adherence to Technical Standards
Petrobras plans to deactivate around 50 oil platforms by the year 2029. This process takes place when the useful life of these structures comes to an end and the procedure needs to be carried out with a lot of planning and observation of technical standards to avoid possible environmental disruptions.
Regina Meyer Branski, professor at the Department of Mining and Petroleum Engineering (PMI) at the Polytechnic School (Poli) of the University of São Paulo, explains the reasons that lead to the deactivation of a platform and how the process should be carried out.
According to the expert, the useful life of an oil field varies between ten and 30 years and, after this period, the wells enter the depletion phase, making the extraction process much more expensive. She states that, at this stage, the withdrawal of the substance is no longer compensatory due to the high costs involved and, therefore, it is necessary to begin the process of deactivating the platform.
“When that reserve runs out, there comes a time when it is no longer financially viable. So, when these wells reach the end of their useful life, the operational cost of carrying out this extraction becomes high and, at that moment, it becomes no longer worthwhile for you to remove the oil and, consequently, the process of deactivating the wells begins. wells”, he explains.
Production system
According to Regina, the oil platform is just a piece of the entire structure that needs to be deactivated. She says that the platform is the part that is visible because it is above the water, but there is a series of pipelines and other equipment submerged in the oceans and, working together, all this equipment forms what is called the Oil Production System.
“So there is not just the platform, but an entire connected system and, when this oil arrives on the platform, it needs to be treated. There is usually a chemical industry on the platforms, because the oil that arrives needs to be separated from the water and gas and, finally, the oil is sent by ship or through a pipeline to the internal reservoir”, he explains.
Deactivation process
According to the professor, the operator of a platform must first prepare a sketch of what will be done during deactivation and, approximately three years beforehand, the deactivation plan must be presented to the National Petroleum Agency (ANP). The body is responsible for observing whether the operator’s process is correct, based on compliance with international standards.
“You have to respect these international standards, you have to analyze what will be removed and treat what will remain, you have to observe what will be fenced off and analyze whether the area is clean. Waste management also needs to be carried out, which can be poisonous and contaminating,” he argues.
According to the professor, the ANP manages this entire process together with Ibama, which is responsible for environmental verification and rehabilitation, and the Navy, which takes care of naval processes, such as moving vessels and adequate signaling. She says that the process carried out on the platforms is similar to that implemented in nuclear installations to ensure the best possible environmental treatment.
Reuse of materials
According to Regina Meyer Branski, the platform’s materials and equipment have different destinations after its deactivation. Some of them are discarded as scrap, others can be recycled or even reused in other locations and some floating platforms can even be transferred to other oil fields.
“It can also be left on the seabed itself, because sometimes, when a fixed platform is overturned, an entire marine biome forms beneath it. So, it might even be interesting to leave it as an artificial reef under the platform and it needs to be monitored frequently afterwards”, he concludes.