Fixed Platforms at Ageing Oil Fields - Feasibility Study for Reuse to Wind Farms

Abstract

All fixed oil platforms in the Brazilian Northeast are near their design lives presenting low productivity. This scenario will lead to a decision-making process about decommissioning. An alternative use for these platforms could be an interesting option to reduce decommissioning costs and social impact. The Brazilian Northeast is already known for its great wind power potential. In this way, this region shows an interesting possibility of reuse fixed oil platforms under decommissioning process to generate wind power. Moreover, many of these fixed platforms are near the coast, installed in shallow waters, close to a major metropolis with significant energy demand, which could potentially reduce the cost of energy transmission. On the wind power operator side, the use of these structures as wind turbine foundation would also reduce the corresponding construction and installation costs. Thus, decommissioning associated with wind turbine installation could be an attractive opportunity for both operators: wind and oil. The objective of this work is to evaluate the technical feasibility of the reuse of these jacket structures for this new proposal, based on economic information already available. On a first step, the work will involve developing a case study in a Brazilian scenario, based on a qualitative analysis of existing wind farm data in Brazil and worldwide. The second step will be to gather global market tendencies, which will be used to define the offshore turbine requirements and data to be used in the following step. Next, the structural capacity of a representative number of jackets will be evaluated considering the wind turbine characteristics defined in the previous steps. A general evaluation will be performed in order to verify the application of the results obtained to all platforms in the field, which will determine the wind farm configuration. Finally, the Levelised Cost of Electricity (LCOE) will be calculated and compared with worldwide values in order to determine the economic viability of the business. This work intends to verify if it is possible to use existing Brazilian offshore oil fields, composed by fixed platforms, as offshore wind farms. For this purpose, a basic methodology to evaluate the structural capability of these structures will be established, which could be applied in other brown fields around the world in the same life situation. Nowadays there are hundreds of ageing platforms/oil fields to be included into decommissioning processes that could be considered as potential Power Wind Farms. The present study could be used as a first approach to permit start a decision-making process, with the adequate region adjustments.

Estudo de viabilidade para a reutilização de plataformas offshore fixa como substrutura de torres eólica

“…Em seu relatório, a Barros et al, (2017) investigou as condições de vento, as condições estruturais de uma plataforma típica sob uma torre de 5 MW e as condições financeiras para então concluir, que uma plataforma de 5 MW, a mais frequente em uso até o início do preparo do artigo, poderia ser usado com sucesso. Mas, vale proferir que passados 3 anos, as torres de 5 MW já não são usadas mais em plataformas offshore, pelo que o mercado hoje oferece ainda torres pequenas para instalações onshore, mas para fins de instalações offshore, quase todas as novas instalações estão sendo feitas com 10MW e as que estão em planejamento já estão sendo projetadas com 12 MW e até 15 MW.…”

“…Desse modo, o presente trabalho de pesquisa pretende responder a pergunta que se impõe, que consiste em saber se a mesma plataforma fixa tipo 1ª família (típica), utilizada pela Barros et al, (2017), podem resistir a uma torre eólica de 10MW. Portanto, objetiva-se avaliar o comportamento da estrutura sem o convés, com carregamento de uma torre de 10 Research, Society and Development, v. 9, n. 10, e2119108618, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i10.8618 5 MW no topo e as novas condições de operação.…”

“…Assim sendo, mesmo para a realidade brasileira, esperase um crescimento dos campos "offshore" nos próximos anos. Barros et al, (2017) e Nogueira (2019), a costa brasileira apresenta excelentes condições eólicas offshore principalmente a região do nordeste, é uma região conhecida como a "área preferencial", resultante da análise económica, que soma uma capacidade instalável de cerca de 126 GW. Vale salientar que, de acordo com Barros et al, (2017), a velocidade máxima é de aproximadamente 9 m/s, o que corresponde a aproximadamente 10,3 m/s a 150 m de altura acima do nível médio dos mares.…”

“…Barros et al, (2017) e Nogueira (2019), a costa brasileira apresenta excelentes condições eólicas offshore principalmente a região do nordeste, é uma região conhecida como a "área preferencial", resultante da análise económica, que soma uma capacidade instalável de cerca de 126 GW. Vale salientar que, de acordo com Barros et al, (2017), a velocidade máxima é de aproximadamente 9 m/s, o que corresponde a aproximadamente 10,3 m/s a 150 m de altura acima do nível médio dos mares. Mudando a referência isso significa que todos os lugares que apresentam média acima de 7,85 m/s têm para 150 m de altura uma média acima dos 9 m/s, considerada excepcional para a instalação de torres eólicas.…”

Offshore Oil and Gas Platforms as Novel Ecosystems: A Global Perspective

“…Decommissioning regulations and options in various countries and regions have been reported on and assessed extensively in the literature. While decommissioning in the North Sea and the United States (US) has been well studied (e.g., Reggio, 1987;Löfstedt and Renn, 1997;Dauterive, 2000;Cripps and Aabel, 2002;Schroeder and Love, 2004;Kaiser and Pulsipher, 2005;Jørgensen, 2012;Claisse et al, 2015), there has been more recent focus on decommissioning policy in relatively "new" oil and gas producing regions, such as south-east Asia (Zawawi et al, 2012;Al-Ghuribi et al, 2016;Fam et al, 2018;Laister and Jagerroos, 2018), Australia (Fowler et al, 2015;Techera and Chandler, 2015;Chandler et al, 2017), and Brazil (Barros et al, 2017;Mimmi et al, 2017). Two recent reviews (Bull and Love, 2019;Sommer et al, 2019) provide comprehensive assessments of the literature on the decommissioning process, options, and regulations around the world.…”