Flow Assurance Applied to CO2 Transport: Challenges of Modelling CO2-Rich Systems through Production, Processing and Injection Systems

Abstract

Abstract High CO2 content fluids present a challenge to the design and operational aspects of production and process facilities due to their particularities related to thermodynamics, hydrodynamic effects, and flow assurance issues. To address these challenges, the present work suggests an integration between different simulation tools to handle the CO2 cycle comprising production, processing, and injection systems. This paper focuses on the modeling challenges imposed by such particular fluids. Traditionally, the state variables adopted for multiphase flow are pressure and temperature, but they usually fail to model phase transitions for pure substances and mixtures with narrow phase envelopes (CO2-rich mixtures). Therefore, to deal with such scenarios, a pressure-enthalpy formulation has been developed so that gas-liquid conditions can be better analyzed. Additionally, to better understand the entire production, processing, and injection system, a parametric analysis has been carried out using the integrated framework. The pressure of the first stage separator (processing section - TOPSIDE) has been varied, leading to an impact on all aspects downstream or upstream of the separator. Results showed that the increase in the first separator pressure decreases the compressor's power requirement per barrel of equivalent oil, but it also decreases the wells production flow rate, worsening the economic performance. In this manner, with the right values, it is possible to achieve optimum oil production while respecting economic and operational constraints.