Wet Compression: Performance Test of a 3D Impeller and Validation of Predictive Model

In the last few years wet compression has received special attention from the oil and gas industry. Here, the development and implementation of new subsea solutions are important focus areas to increase production and recovery from existing fields. This new technology will contribute to exploitation of small and remote fields and access in very deep water. In this regard liquid tolerance represents a viable option to reduce the cost of a subsea compression station bringing considerable simplification to the subsea process itself. However, the industry may experience some drawbacks: the various levels of liquid presence may create operational risk for traditional compressors; the liquid may cause mechanical damage because of erosion and corrosion of the internal units and the compressor performance might be affected too. The experimental investigation conducted in the study considers dry and wet conditions in a laboratory setup to understand how the presence of liquid influences the stage performance. The test campaign has been carried out at the Norwegian University of Science and Technology, NTNU, in Trondheim, to assess the performance and operating range of a tridimensional impeller when processing a mixture of gas and liquid phases. Experimental results allowed validating the OEM internal prediction code for compressors’ performance in wet conditions. Finally, the effect of liquid on machine operability has been assessed through a left-limit investigation by means of dynamic pressure probes readings in order to evaluate the stall/surge behaviour for different values of liquid mass fraction.