Advances in multiphase flow modelling boost oil pipeline efficiency

Cutting-edge computational models and experimental research, like AspenTech's HYSYS and Tulsa Unified Model, enhance multiphase flow predictions, improving safety, cost-efficiency, and sustainability in oil and gas pipeline operations

- 

IN the intricate world of the oil and gas industry, the transport of multiphase fluids — combinations of gas, liquid, and sometimes solids — through pipelines represents a formidable engineering challenge.

This phenomenon, known as multiphase flow, is pivotal for efficient production and transportation, enabling the movement of unseparated fluid mixtures over vast distances.

From offshore rigs to onshore processing plants, accurately predicting and managing multiphase flow ensures safer, cost-effective, and environmentally sustainable operations.

A white paper by AspenTech, a leading software supplier for optimising asset performance, explores advances in computational modelling, such as those in Aspen HYSYS®, coupled with cutting-edge experimental research, are transforming how engineers tackle this complexity, addressing issues like pressure gradients, liquid holdup, and flow regimes that dictate pipeline performance.

Multiphase flow through pipes is defined by the simultaneous movement of multiple phases, typically gas and liquid, but occasionally including water or solids.

Unlike single-phase flow, where fluid properties are uniform, multiphase flow exhibits varied spatial arrangements, or flow regimes, such as stratified, slug, annular, or bubbly flow.

These regimes depend on factors like pipe geometry, fluid properties, and flow velocities. For instance, in horizontal pipes, gas may travel atop a liquid layer in stratified flow, while vertical pipes might see gas bubbles dispersed in a liquid matrix.

Each regime influences critical parameters: The pressure gradient (pressure drop per unit length), liquid holdup (the fraction of liquid in the pipe), and frictional losses, all of which are essential for designing robust pipelines.