Fabricio Oliveira | RMIT University (original) (raw)

Papers by Fabricio Oliveira

Research paper thumbnail of A New Mathematical Model for the Workover Rig Scheduling Problem

Pesquisa Operacional, 2016

One of the most important activities in the oil and gas industry is the intervention in wellsfor ... more One of the most important activities in the oil and gas industry is the intervention in wellsfor maintenance services, which is necessary to ensure the constant production of oil. These interventions are carried out by workover rigs. Thus, the Workover Rig Scheduling Problem (WRSP) consists of finding the best schedule to service the wells while considering the limited number of rigs with the objective of minimizing the total production loss. In this study, a 0-1 integer linear programming model capable of efficiently solving the WRSP with a homogeneous fleet of rigs is proposed. Computational experiments were carried out using instances based on real cases in Brazil to compare the results obtained by the proposed model with the results reported by other methods. The proposed model was capable of solving all instances considered in a reduced computational time, including the large instances for which only approximatesolutions were presently known.

Research paper thumbnail of Plano Estratégico da Produção de Biodiesel Utilizando Mamona Através de Modelo de Programação Linear Inteira-Mista

Sistemas Gestao, Dec 19, 2014

Neste trabalho, é apresentado o planejamento estratégico da cadeia de suprimentos de biodiesel pr... more Neste trabalho, é apresentado o planejamento estratégico da cadeia de suprimentos de biodiesel produzido a partir da mamona. Esta cadeia possui a particularidade de ser baseada em agricultura familiar, o que dificulta o envio de cargas para as usinas de esmagamento e compromete a eficiência logística da cadeia. Uma alternativa para minimizar o custo logístico total da operação consiste na instalação de entrepostos que concentrem a produção dos agricultores antes do envio ao esmagamento, de forma a aumentar a taxa de ocupação dos caminhões e, dessa forma, reduzir custos. No entanto, a definição da localização ótima de tais entrepostos envolve um problema combinatório complexo. Dessa forma, é proposto um modelo matemático de programação linear inteira-mista (PLIM) que visa apoiar o processo de desenho da rede logística com o foco em minimizar seus custos de instalação e operação. Como principal resultado do trabalho, destaca-se a rede logística otimizada, indicando os fluxos e entrepostos a serem instalados. Além disto, é mostrado impacto da quebra de safra no projeto da cadeia de suprimentos, que pode representar um grande impacto no número de entrepostos que deverão compor a cadeia.

Research paper thumbnail of A Strategy Based on Convex Relaxation for Solving the Oil Refinery Operations Planning Problem

Industrial & Engineering Chemistry Research, 2016

Research paper thumbnail of Design of a hydrogen supply chain with uncertainty

International Journal of Hydrogen Energy, 2015

Research paper thumbnail of Sistema de Otimização Aplicado ao Processamento de Gás Natural no Espírito Santo

Research paper thumbnail of Análise do Planejamento de Abastecimento da Cadeia de Petróleo no Brasil

Research paper thumbnail of Application of L-Shaped decomposition techniques for the problem of supply chain investment planning under demand uncertainty

Research paper thumbnail of Genetic Algorithms Applied to Scheduling and Optimization of Refinery Operations

Research paper thumbnail of A Primal Decomposition Approach For The Supply Chain Investment Planning Problem Under Demand Uncertainty

This paper presents the application of a primal decomposition algorithm for the problem of supply... more This paper presents the application of a primal decomposition algorithm for the problem of supply chain investment planning under uncertainty applied to the petroleum products supply chain. The uncertainty considered is related with the unknown demand levels for oil products. For this purpose, a model was developed based on two-stage stochastic programming. It is proposed two different solution methodologies, one based on the classical cutting plane approach presented by , and other, based on a multi cut extension of it, firstly introduced by Birge and Louveaux (1988). The methods were evaluated on a real sized case study. Preliminary numerical results obtained from computational experiments are encouraging.

Research paper thumbnail of Análise de Investimentos na Cadeia de Suprimentos Downstream da Indústria Petrolífera: Proposta de um Modelo de Programação Linear Inteira Mista

Research paper thumbnail of Desenvolvimento de uma ferramenta gráfica para sistemas de otimização do abastecimento de petróleo e derivados

Resumo: O desenvolvimento de um sistema de planejamento de investimentos voltado ao parque de ref... more Resumo: O desenvolvimento de um sistema de planejamento de investimentos voltado ao parque de refino brasileiro esbarra em uma série de dificuldades, para que se obtenha a distribuição ótima de recursos no que tange ao processo de refino, bem como na distribuição de derivados. Este artigo tem o intuito de apresentar as principais características do Sistema de Modelagem adotado para a geração e otimização do sistema integrado de planejamento de investimentos para o abastecimento brasileiro de petróleo e derivados. Este sistema considera a expansão e otimização do parque de refino e da logística do abastecimento, bem como aspectos quanto a comercialização, oferta e demanda de petróleos e seus derivados. A principal ênfase do artigo será na interface gráfica de modelagem, que permite a montagem intuitiva de esquemas de refino.

Research paper thumbnail of Stochastic Benders decomposition for the supply chain investment planning problem under demand uncertainty

Pesquisa Operacional, 2012

This paper presents the application of a stochastic Benders decomposition algorithm for the probl... more This paper presents the application of a stochastic Benders decomposition algorithm for the problem of supply chain investment planning under uncertainty applied to the petroleum byproducts supply chain. The uncertainty considered is related with the unknown demand levels for oil products. For this purpose, a model was developed based on two-stage stochastic programming. It is proposed two different solution methodologies, one based on the classical cutting plane approach presented by , and other, based on a multi cut extension of it, firstly introduced by Birge & Louveaux (1988). The methods were evaluated on a real sized case study. Preliminary numerical results obtained from computational experiments are encouraging.

Research paper thumbnail of Process industry scheduling optimization using genetic algorithm and mathematical programming

Journal of Intelligent Manufacturing, 2011

This article addresses the problem of scheduling in oil refineries. The problem consists of a mul... more This article addresses the problem of scheduling in oil refineries. The problem consists of a multi-product plant scheduling, with two serial machine stages-a mixer and a set of tanks-which have resource constraints and operate on a continuous flow basis. Two models were developed: the first using mixed-integer linear programming (MILP) and the second using genetic algorithms (GA). Their main objective was to meet the whole forecast demand, observing the operating constraints of the refinery and minimizing the number of operational changes. A real-life data-set related to the production of fuel oil and asphalt in a large refinery was used. The MILP and GA models proved to be good solutions for both primary objectives, but the GA model resulted in a smaller number of operational changes. The reason for this is that GA incorporates a multi-criteria approach, which is capable of adaptively updating the weights of the objective throughout the evolutionary process.

Research paper thumbnail of Optimization of the Petroleum Product Supply Chain under Uncertainty: A Case Study in Northern Brazil

Industrial & Engineering Chemistry Research, 2012

ABSTRACT This Article addresses the problem of optimizing the investment planning process of a lo... more ABSTRACT This Article addresses the problem of optimizing the investment planning process of a logistics infrastructure for the distribution of petroleum products under uncertainty. For this purpose, a two-stage stochastic model was developed. Because of the large number of possible scenarios for the future realization of demands, the Sample Average Approximation (SAA) methodology was used to produce approximations of the optimal solution. The proposed model and solution methodology were applied to a real case study on the distribution of petroleum products in northern Brazil. The results show that the methodology allows us to obtain solutions that are relatively close to the real optimal solution of the problem with optimality gaps estimated at up to 1%, which are reasonable for most practical purposes.

Research paper thumbnail of Contingency-Constrained Unit Commitment With <formula formulatype="inline"><tex Notation="TeX">$n - K$</tex></formula> Security Criterion: A Robust Optimization Approach

IEEE Transactions on Power Systems, 2000

This paper presents a new approach for the contingency-constrained single-bus unit commitment pro... more This paper presents a new approach for the contingency-constrained single-bus unit commitment problem. The proposed model explicitly incorporates an security criterion by which power balance is guaranteed under any contingency state comprising the simultaneous loss of up to generation units. Instead of considering all possible contingency states, which would render the problem intractable, a novel method based on robust optimization is proposed. Using the notion of umbrella contingency, the robust counterpart of the original problem is formulated. The resulting model is a particular instance of bilevel programming which is solved by its transformation to an equivalent single-level mixed-integer programming problem. Unlike previously reported contingencydependent approaches, the robust model does not depend on the size of the set of credible contingencies, thus providing a computationally efficient framework. Simulation results back up these conclusions.

Research paper thumbnail of Accelerating benders stochastic decomposition for the optimization under uncertainty of the petroleum product supply chain

Computers & Operations Research, 2014

Research paper thumbnail of A Lagrangean decomposition approach for oil supply chain investment planning under uncertainty with risk considerations

Computers & Chemical Engineering, 2013

We present a scenario decomposition framework based on Lagrangean decomposition for the multi-pro... more We present a scenario decomposition framework based on Lagrangean decomposition for the multi-product, multi-period, supply investment planning problem considering network design and discrete capacity expansion under demand uncertainty. We also consider a risk measure that allows us to reduce the probability of incurring in high costs while preserving the decomposable structure of the problem. To solve the resulting large-scale two-stage mixed-integer stochastic linear programming problem, we propose a novel Lagrangean decomposition scheme. In this context, we compare different formulations for the non-anticipativity conditions. In addition to that, we present a new hybrid algorithm for updating the Lagrangean multiplier set, based on the combination of cutting-plane, subgradient and trust-region strategies. Numerical results suggests that different formulations of the non-anticipativity conditions have a significant effect on the performance of the algorithm. Moreover, we observe that the proposed hybrid approach has superior performance when compared with the traditional subgradient algorithm in terms of faster computational times for the problem addressed in this work.

Research paper thumbnail of Optimization of biodiesel supply chains based on small farmers: A case study in Brazil

Bioresource Technology, 2011

This article presents a methodology for conceiving and planning the development of an optimized s... more This article presents a methodology for conceiving and planning the development of an optimized supply chain of a biodiesel plant sourced from family farms and taking into consideration agricultural, logistic, industrial, and social aspects. This model was successfully applied to the production chain of biodiesel fuel from castor oil in the semi-arid region of Brazil. Results suggest important insights related to the optimal configuration of the crushing units, regarding its location, technology, and when it should be available, as well as the configuration of the production zones along the planning horizon considered. Moreover, a sensitivity analysis is performed in order to measure how possible variations in the considered conjecture can affect the robustness of the solutions.

Research paper thumbnail of Energy and Reserve Scheduling Under an NK Security Criterion via Robust Optimization

Research paper thumbnail of A Robust Approach for the Biodiesel Supply Chain Based on Small Farmers

sobrapo.org.br

The strategy adopted by the Brazilian Biodiesel Program is to base its fuel production on grains ... more The strategy adopted by the Brazilian Biodiesel Program is to base its fuel production on grains acquired from small, family-owned farms in the poorest regions of the country, thereby fostering social inclusion and transfer of income. The success of the program depends on ...

Research paper thumbnail of A New Mathematical Model for the Workover Rig Scheduling Problem

Pesquisa Operacional, 2016

One of the most important activities in the oil and gas industry is the intervention in wellsfor ... more One of the most important activities in the oil and gas industry is the intervention in wellsfor maintenance services, which is necessary to ensure the constant production of oil. These interventions are carried out by workover rigs. Thus, the Workover Rig Scheduling Problem (WRSP) consists of finding the best schedule to service the wells while considering the limited number of rigs with the objective of minimizing the total production loss. In this study, a 0-1 integer linear programming model capable of efficiently solving the WRSP with a homogeneous fleet of rigs is proposed. Computational experiments were carried out using instances based on real cases in Brazil to compare the results obtained by the proposed model with the results reported by other methods. The proposed model was capable of solving all instances considered in a reduced computational time, including the large instances for which only approximatesolutions were presently known.

Research paper thumbnail of Plano Estratégico da Produção de Biodiesel Utilizando Mamona Através de Modelo de Programação Linear Inteira-Mista

Sistemas Gestao, Dec 19, 2014

Neste trabalho, é apresentado o planejamento estratégico da cadeia de suprimentos de biodiesel pr... more Neste trabalho, é apresentado o planejamento estratégico da cadeia de suprimentos de biodiesel produzido a partir da mamona. Esta cadeia possui a particularidade de ser baseada em agricultura familiar, o que dificulta o envio de cargas para as usinas de esmagamento e compromete a eficiência logística da cadeia. Uma alternativa para minimizar o custo logístico total da operação consiste na instalação de entrepostos que concentrem a produção dos agricultores antes do envio ao esmagamento, de forma a aumentar a taxa de ocupação dos caminhões e, dessa forma, reduzir custos. No entanto, a definição da localização ótima de tais entrepostos envolve um problema combinatório complexo. Dessa forma, é proposto um modelo matemático de programação linear inteira-mista (PLIM) que visa apoiar o processo de desenho da rede logística com o foco em minimizar seus custos de instalação e operação. Como principal resultado do trabalho, destaca-se a rede logística otimizada, indicando os fluxos e entrepostos a serem instalados. Além disto, é mostrado impacto da quebra de safra no projeto da cadeia de suprimentos, que pode representar um grande impacto no número de entrepostos que deverão compor a cadeia.

Research paper thumbnail of A Strategy Based on Convex Relaxation for Solving the Oil Refinery Operations Planning Problem

Industrial & Engineering Chemistry Research, 2016

Research paper thumbnail of Design of a hydrogen supply chain with uncertainty

International Journal of Hydrogen Energy, 2015

Research paper thumbnail of Sistema de Otimização Aplicado ao Processamento de Gás Natural no Espírito Santo

Research paper thumbnail of Análise do Planejamento de Abastecimento da Cadeia de Petróleo no Brasil

Research paper thumbnail of Application of L-Shaped decomposition techniques for the problem of supply chain investment planning under demand uncertainty

Research paper thumbnail of Genetic Algorithms Applied to Scheduling and Optimization of Refinery Operations

Research paper thumbnail of A Primal Decomposition Approach For The Supply Chain Investment Planning Problem Under Demand Uncertainty

This paper presents the application of a primal decomposition algorithm for the problem of supply... more This paper presents the application of a primal decomposition algorithm for the problem of supply chain investment planning under uncertainty applied to the petroleum products supply chain. The uncertainty considered is related with the unknown demand levels for oil products. For this purpose, a model was developed based on two-stage stochastic programming. It is proposed two different solution methodologies, one based on the classical cutting plane approach presented by , and other, based on a multi cut extension of it, firstly introduced by Birge and Louveaux (1988). The methods were evaluated on a real sized case study. Preliminary numerical results obtained from computational experiments are encouraging.

Research paper thumbnail of Análise de Investimentos na Cadeia de Suprimentos Downstream da Indústria Petrolífera: Proposta de um Modelo de Programação Linear Inteira Mista

Research paper thumbnail of Desenvolvimento de uma ferramenta gráfica para sistemas de otimização do abastecimento de petróleo e derivados

Resumo: O desenvolvimento de um sistema de planejamento de investimentos voltado ao parque de ref... more Resumo: O desenvolvimento de um sistema de planejamento de investimentos voltado ao parque de refino brasileiro esbarra em uma série de dificuldades, para que se obtenha a distribuição ótima de recursos no que tange ao processo de refino, bem como na distribuição de derivados. Este artigo tem o intuito de apresentar as principais características do Sistema de Modelagem adotado para a geração e otimização do sistema integrado de planejamento de investimentos para o abastecimento brasileiro de petróleo e derivados. Este sistema considera a expansão e otimização do parque de refino e da logística do abastecimento, bem como aspectos quanto a comercialização, oferta e demanda de petróleos e seus derivados. A principal ênfase do artigo será na interface gráfica de modelagem, que permite a montagem intuitiva de esquemas de refino.

Research paper thumbnail of Stochastic Benders decomposition for the supply chain investment planning problem under demand uncertainty

Pesquisa Operacional, 2012

This paper presents the application of a stochastic Benders decomposition algorithm for the probl... more This paper presents the application of a stochastic Benders decomposition algorithm for the problem of supply chain investment planning under uncertainty applied to the petroleum byproducts supply chain. The uncertainty considered is related with the unknown demand levels for oil products. For this purpose, a model was developed based on two-stage stochastic programming. It is proposed two different solution methodologies, one based on the classical cutting plane approach presented by , and other, based on a multi cut extension of it, firstly introduced by Birge & Louveaux (1988). The methods were evaluated on a real sized case study. Preliminary numerical results obtained from computational experiments are encouraging.

Research paper thumbnail of Process industry scheduling optimization using genetic algorithm and mathematical programming

Journal of Intelligent Manufacturing, 2011

This article addresses the problem of scheduling in oil refineries. The problem consists of a mul... more This article addresses the problem of scheduling in oil refineries. The problem consists of a multi-product plant scheduling, with two serial machine stages-a mixer and a set of tanks-which have resource constraints and operate on a continuous flow basis. Two models were developed: the first using mixed-integer linear programming (MILP) and the second using genetic algorithms (GA). Their main objective was to meet the whole forecast demand, observing the operating constraints of the refinery and minimizing the number of operational changes. A real-life data-set related to the production of fuel oil and asphalt in a large refinery was used. The MILP and GA models proved to be good solutions for both primary objectives, but the GA model resulted in a smaller number of operational changes. The reason for this is that GA incorporates a multi-criteria approach, which is capable of adaptively updating the weights of the objective throughout the evolutionary process.

Research paper thumbnail of Optimization of the Petroleum Product Supply Chain under Uncertainty: A Case Study in Northern Brazil

Industrial & Engineering Chemistry Research, 2012

ABSTRACT This Article addresses the problem of optimizing the investment planning process of a lo... more ABSTRACT This Article addresses the problem of optimizing the investment planning process of a logistics infrastructure for the distribution of petroleum products under uncertainty. For this purpose, a two-stage stochastic model was developed. Because of the large number of possible scenarios for the future realization of demands, the Sample Average Approximation (SAA) methodology was used to produce approximations of the optimal solution. The proposed model and solution methodology were applied to a real case study on the distribution of petroleum products in northern Brazil. The results show that the methodology allows us to obtain solutions that are relatively close to the real optimal solution of the problem with optimality gaps estimated at up to 1%, which are reasonable for most practical purposes.

Research paper thumbnail of Contingency-Constrained Unit Commitment With <formula formulatype="inline"><tex Notation="TeX">$n - K$</tex></formula> Security Criterion: A Robust Optimization Approach

IEEE Transactions on Power Systems, 2000

This paper presents a new approach for the contingency-constrained single-bus unit commitment pro... more This paper presents a new approach for the contingency-constrained single-bus unit commitment problem. The proposed model explicitly incorporates an security criterion by which power balance is guaranteed under any contingency state comprising the simultaneous loss of up to generation units. Instead of considering all possible contingency states, which would render the problem intractable, a novel method based on robust optimization is proposed. Using the notion of umbrella contingency, the robust counterpart of the original problem is formulated. The resulting model is a particular instance of bilevel programming which is solved by its transformation to an equivalent single-level mixed-integer programming problem. Unlike previously reported contingencydependent approaches, the robust model does not depend on the size of the set of credible contingencies, thus providing a computationally efficient framework. Simulation results back up these conclusions.

Research paper thumbnail of Accelerating benders stochastic decomposition for the optimization under uncertainty of the petroleum product supply chain

Computers & Operations Research, 2014

Research paper thumbnail of A Lagrangean decomposition approach for oil supply chain investment planning under uncertainty with risk considerations

Computers & Chemical Engineering, 2013

We present a scenario decomposition framework based on Lagrangean decomposition for the multi-pro... more We present a scenario decomposition framework based on Lagrangean decomposition for the multi-product, multi-period, supply investment planning problem considering network design and discrete capacity expansion under demand uncertainty. We also consider a risk measure that allows us to reduce the probability of incurring in high costs while preserving the decomposable structure of the problem. To solve the resulting large-scale two-stage mixed-integer stochastic linear programming problem, we propose a novel Lagrangean decomposition scheme. In this context, we compare different formulations for the non-anticipativity conditions. In addition to that, we present a new hybrid algorithm for updating the Lagrangean multiplier set, based on the combination of cutting-plane, subgradient and trust-region strategies. Numerical results suggests that different formulations of the non-anticipativity conditions have a significant effect on the performance of the algorithm. Moreover, we observe that the proposed hybrid approach has superior performance when compared with the traditional subgradient algorithm in terms of faster computational times for the problem addressed in this work.

Research paper thumbnail of Optimization of biodiesel supply chains based on small farmers: A case study in Brazil

Bioresource Technology, 2011

This article presents a methodology for conceiving and planning the development of an optimized s... more This article presents a methodology for conceiving and planning the development of an optimized supply chain of a biodiesel plant sourced from family farms and taking into consideration agricultural, logistic, industrial, and social aspects. This model was successfully applied to the production chain of biodiesel fuel from castor oil in the semi-arid region of Brazil. Results suggest important insights related to the optimal configuration of the crushing units, regarding its location, technology, and when it should be available, as well as the configuration of the production zones along the planning horizon considered. Moreover, a sensitivity analysis is performed in order to measure how possible variations in the considered conjecture can affect the robustness of the solutions.

Research paper thumbnail of Energy and Reserve Scheduling Under an NK Security Criterion via Robust Optimization

Research paper thumbnail of A Robust Approach for the Biodiesel Supply Chain Based on Small Farmers

sobrapo.org.br

The strategy adopted by the Brazilian Biodiesel Program is to base its fuel production on grains ... more The strategy adopted by the Brazilian Biodiesel Program is to base its fuel production on grains acquired from small, family-owned farms in the poorest regions of the country, thereby fostering social inclusion and transfer of income. The success of the program depends on ...