Control of electrical submersible pumps in two-phase liquid-liquid flow

Author(s)

Mauricio Barrios Castellanos

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Mecânica
• Defense date: 2024-04-01

Examining board members

Alberto Luiz Serpa; Janito Vaqueiro Ferreira; William Monte Verde; Oscar Mauricio Hernandez Rodriguez; Idelfonso Bessa dos Reis Nogueira

• Advisor: Alberto Luiz Serpa; Jorge Luiz Biazussi

Abstract

Electrical Submersible Pumps (ESPs) are centrifugal pumps widely utilized for artificial lift. ESPs can operate under severe operational conditions such as abrasion, high viscosity flows, and gas, oil, and water multiphase flows. When the predominant phases are water and oil, the flow is considered a liquid-liquid two-phase. These mixtures form emulsions that can cause operational instabilities due to effective viscosity and density changes. Control strategies capable of maintaining stable pump operation under liquid-liquid flows are necessary. This work proposes and implements a Damage-Tolerant Active Control (DTAC) approach that can tolerate the instabilities produced by variations in emulsion properties. For this purpose, a Model Predictive Control (MPC) is proposed. The proposed model consists of a Non-Linear steady-state Model (NLM) coupled with a linear State Space Model (SSM), monitoring variations in emulsion effective viscosity and density based on vibration monitoring. The proposed methodology involves conducting experiments on ESPs operating with a water-oil biphasic mixture, replicating the behavior of ESPs operating with emulsion both in steady-state and transient regimes. The steady-state modeling of the ESP and the system components was carried out using a NLM. The transient modeling of the system was accomplished through a linear SSM. Fluid properties were monitored by measuring Flow Induced Vibrations (FIV) and implementing Artificial Neural Networks (ANN). An MPC strategy that couples the NLM and SSM with FIV monitoring was proposed. The control strategy was tested through computational simulations and on the experimental bench in BCSs operating with emulsions, presenting steady-state error around 5%, and stabilization times around 150 seconds (AU)

• FAPESP's process: 19/10249-2 - Control of Electrical Submersible Pumps in two-phase liquid-liquid flow
• Grantee: Mauricio Barrios Castellanos
• Support Opportunities: Scholarships in Brazil - Doctorate