Modeling of flow splitting for production optimization in offshore gas-lifted oil fields: Simulation validation and applications

• Flow splitting modeling in subsea equipment.
• Mixed-integer programming model with automatic well-manifold routing for production optimization.
• Computational and simulation analysis of the automatic routing model.
• Multiple routing solutions reach higher overall production for a realistic offshore field.

In modern offshore oil fields, wells can be equipped with routing valves to direct their production to multiple manifold headers, a strategy that is routinely adopted in practice either to provide resilience to equipment failure or to improve production. However, the existing models for production optimization do not account for splitting of flows and therefore require the wells to be connected to a single header. To this end, this work develops a nonlinear model of flow splitting that reproduces the complex behavior observed in multiphase-flow simulation. This model is further approximated with multidimensional piecewise-linear functions to a desired degree of accuracy with respect to simulated behavior. These piecewise-linear functions enable the development of a Mixed-Integer Linear Programming (MILP) formulation for production optimization, which decides between single and multiple routing of wells to headers. The effectiveness of this MILP formulation is assessed in a synthetic but representative gas-lifted oil field modeled in a standard simulator.