Wet Gas Compressor Operation and Performance

The continuous demand for oil and gas forces the petroleum industry to develop new and cost-effective technologies to increase recovery from new fields and enhance extraction from existing fields. Subsea wet gas compression stands out as a promising solution for increasing production capacity, utilizing remote regions and reducing costs. A prerequisite for successful oil and gas production utilizing subsea wet gas compressors is operability. This includes the system's ability to cope with operational changes, without having to shut down. One of the fundamental operational changes is the liquid content in the inlet pipe, which may fluctuate considerably at certain time intervals. The current study investigates how changes in liquid content impacts compressor performance. An experimental test campaign has been performed at the Norwegian University of Science and Technology (NTNU). The test facility is an open loop configuration consisting of a single shrouded centrifugal impeller, a vaneless diffuser and a symmetrical circular volute. The main objectives were to document how the presence of liquid impacts the compressor characteristics and further, how the operating point moves within the characteristics when solely subjected to an increase of liquid content. The compressor was exposed to liquid contents ranging from gas mass fraction 1.0 to 0.60. The test reveals that the compressor pressure ratio at wet conditions is higher in comparison to dry conditions. Care should be taken when analysing stability and surge margins at variations in fluid liquid content. Further, the compressor behaves in a predictable manner, revealing several linear trends, when subjected to stepwise changes in liquid content from a fixed operating point.