Framework for one-dimensional (1D) models of multiphase flows with hydrate transport and agglomeration in ALFAsim™

Client: Repsol Sinopec Brazil | Partner: ESSS

Gas hydrates are ice-like structures that usually form at low-temperature and high-pressure conditions in which a small hydrocarbon molecule is trapped inside a cage of hydrogen-bonded water molecules. One potential strategy for hydrate management involves allowing hydrates to form, while minimizing the risks of creating large deposits that agglomerate and adhere onto the pipeline walls, which may severely restrict the flow. In order to employ such a strategy, it is fundamental to understand the right conditions that allow hydrate particles to be transported safely within a multiphase slurry flow. These may involve various inter-related aspects of the fluids composition and chemical additives/inhibitors, the thermal and hydrodynamic aspects of the flow (including emulsion behavior) and, of course, the optimal operational conditions.

The present project aims at developing an offline transient model advisor to understand the relevant hydrate mechanisms for a given system, and assist the design and optimization of field operations inside the hydrates envelope. Some of the important knowledge elements are related to the following aspects:

1) Thermodynamic and kinetic behavior (hydrate equilibrium, thermodynamic inhibition, nucleation limitation, induction time increase, role of anti-agglomerants, etc)

2) Emulsion, free water and interfacial behavior: how is the water distributed in the system? What is the water-cut threshold above which free water is present? How does surface chemistry play a role?

3) Slurry transport: even in non-plugging systems, high hydrate particle concentrations may create a very viscous (eventually non-Newtonian) slurry with low transportability.