On application of a zone IHMPC to an ESP-lifted oil well system

Abstract

This paper presents an application of a stabilizing model predictive control (IHMPC) strategy with the underlying guarantee of feasibility to an oil production well system with Electric Submersible Pump (ESP) installation. The proposed controller is compared with a conventional finite-horizon MPC which provides some unfeasible solutions in the presence of an unmeasured disturbance, due to the typical conflict among the ESP-lifted oil well system constraints. The results show IHMPC as a viable choice to improve ESP-lifted well production since it can incorporate the desired requirements and provides stabilizing control actions.

Embedded MPC Strategies for ESP-Lifted Oil Wells: Hardware-in-the-Loop Performance Analysis of Nonlinear and Robust Techniques

“…Despite ongoing advances, the strategies mentioned so far do not consider either guarantee of stability or feasibility for MPC control laws. Fontes et al [11] was the first to propose a stabilizing MPC strategy with guaranteed feasibility for such systems. This strategy is based on an infinite-horizon MPC (IHMPC) controller that explicitly includes the down-thrust and up-thrust constraints such as a softening target zone scheme.…”

“…To overcome the limitations from [12,13], Santana et al [15] proposed an adaptive and feasible zone IHMPC scheme based on Fontes et al [11], applying successive linearization of a nonlinear phenomenological model to accommodate the complexities and uncertainties present in the ESP-equipped systems and directly dealing with the pump envelope constraints. However, this strategy does not have robustly stabilizing properties, despite the performance improvement compared to the linear model-based IHMPC [11]. Matos et al [9] extended that approach, treating the adaptation of the prediction model by a fuzzy structure, which combines data-based local linear models as a linear parametervarying model.…”

“…To reach this objective, the intake pressure is taken as a controlled variable that must track a setpoint. Additionally, the head can be treated as another controlled variable, requiring the zone-control approach to softly define its optimal setpoint based on the limits defined by the operational envelope [11].…”

Controlador preditivo de horizonte infinito embarcado: aplicação hardware-in-the-loop a um sistema de bombeio centrífugo submerso

“…Uma questão em aberto nos trabalhos supracitados, diz respeito à garantia de estabilidade em malha fechada e factibilidade dos controladores MPC propostos, visto que tais formulações são baseadas em horizontes de predição finitos e suas leis de controle podem se tornar facilmente inviáveis devido ao conflito típico que ocorre entre as restrições do sistema BCS. Diante disso, Fontes et al (2020) propuseram a aplicação de um MPC de horizonte de predição infinito (IHMPC) para um sistema BCS, considerando o modelo dinâmico concebido por Pavlov et al (2014). Os autores utilizaram uma estratégia de controle por faixa para rastrear o envelope operacional (restrições variantes no tempo), que suaviza, somente quando necessário, o conflito típico existente nas restrições das saídas do sistema BCS, através do uso de restrições terminais suavizadas e de set-points artificiais.…”

“…Este artigo tem como proposta investigar os aspectos de implementação do controlador IHMPC explorado em Fontes et al (2020), validando-o através do teste hardware-in-the-loop com a planta virtual simulada em MATLAB. A viabilidade de embarcar o IHMPC é investigada Figura 1: Esquema de um processo de produção de petróleo com instalação BCS.…”