FEESA, Fluid Economics and Systems Analysis

WWW.FEESA.NET

Flow Assurance & Optimisation of Oil & Gas Production

Slugs & Surges

In many oil and gas developments with multiphase flowlines, multiphase instability is a major Flow Assurance concern due to the excessive demands large changes in oil and gas flow rates put upon the processing facilities. These multiphase surges come in three forms:

Hydrodynamic Slugs: A feature of the slug flow regime where slugs are formed due to instability of waves at certain gas-liquid flow rates.

Terrain Induced Slugs: including severe slugs, caused by accumulation and periodic purging of liquid in dips in the flowline at low flow rates.

Operationally Induced Surges: Generated by forcing the flowline from one steady state to another can upset the system such that a liquid surge is generated, e.g. during flow rate ramp-up or pigging operations.

As these three forms of surges are very different, they require different analytical techniques.

Click on the links to read more.