Thermo hydraulic simulation for heavy oil pipeline systems: Lessons learned for the Faja fields

The thermo hydraulic simulations for pipeline systems are a common activity for oil fields. These are used to design pipeline systems. Moreover, simulations allow evaluation of existing pipeline systems to identify bottleneck that could affect production handling and transport due to capacity limitations of surface facilities or changing process variables (GOR, properties of fluids, water cut, etc). Thermo-hydraulic simulations require the use of suitable mathematical models to reduce prediction uncertainty leading to improve and optimize pipeline systems design and operation contributing to reduce both CAPEX and OPEX. In this sense, some authors have estimated that investment costs related to a proper pipeline sizing could account for over 25% of the total project cost for onshore facilities. Given this economic impact, engineers must make efforts to develop a rigorous simulation model considering the best practices for their field. Thermo-hydraulic studies of pipeline systems located in the Faja using simulations are challenging due to multiphase flow conditions, high liquid viscosities, hilly-terrain and ambient temperature changes that generate high pressure drop and slug flow, as well as pressure and flow rate fluctuations. These conditions imply that the simulation model requires technical knowledge together with experience associated to the interest oil field. Both requirements help to the simulation engineers to implement lessons learned to predict the hydraulic behavior much better leading to define strategies to improve design and operation of pipeline systems. About this an overview of lessons learned for Faja field is presented in this work. These lessons learned consider recommendations aiming to reduce uncertainty in predicting heavy oil properties, pressure drop, temperature, flow pattern and liquid holdup that lead to optimize production process, invest and operational costs. These advices are a guide to simulation engineers in order to develop more rigorous simulation models to estimate pipeline hydraulic behavior as close to reality