Review of Wet Gas Compressor Performance
Subsea wet gas compression without preliminary separation give an opportunity to develop mature and remote gas/condensate field. Predicting wet gas compressor performance is important to develop those fields. Currently there is no standard exist for wet gas compression performance calculation (Hundseid et al., 2008). The current standards (ISO 5389:2005) exist only for dry gas by utilizing Schultz method.
In wet gas compression, fluid properties are changing as fluid being compressed. Schultz method may not be accurate to be applied in wet gas compression since it uses average fluid properties between inlet and outlet of the compressor.
The necessities of standard in wet gas compression encourage this project to conduct a research in wet gas compression performance. This project will evaluate Huntington direct integration method (Huntington, 1985) which originally for dry gas to be used in wet gas compression calculation and compare the result with Schultz method.
In this project, visual basic script was created to calculate wet gas compressor performance by using direct integration method. Fluid properties are calculated by HYSYSTM software. It is also desired to know how HYSYSTM calculate wet gas compression. Compressor off design operation effect on compressor performance is also taken into consideration when calculating wet gas compressor performance.
The results show that direct integration method is much more suitable for wet gas compression calculation compared to Schultz method. As wet gas being compressed, more liquid will form in the mixture and it will affect fluid properties. The presence of heavier fluid in the mixture and cooling effect is one of the factor that affecting compressor performance. This factor will reduce specific polytopic head of compressor. Direct integration method calculation is considering this effect.
Off design operation affect compressor performance calculation significantly. The deviation between original performance and corrected performance become larger as actual and reference condition become much more different. At large deviation, the corrected compressor performances become uncertain.
In HYSYSTM software, interaction between liquid and vapor phase is taken into consideration. The software does not calculate compressor performance by treating each phase separately.
Further recommendations for this project are to compare calculated performance using direct integration method with actual experiment and improvement of current compressor off design correction. By comparing compressor performance calculation with real data, the accuracy of direct integration method will be discovered. In gas condensate field, fluid properties will change significantly with decreasing pressure. Therefore, actual and test reference condition will be different over time and will affect gas condensate field performance. This condition need attention since current off design correction accuracy will be reduced if the deviation is large. Good prediction of wet gas compression performance is required in developing gas condensate field
Place, publisher, year, edition, pages
Institutt for petroleumsteknologi og anvendt geofysikk , 2014. , 96 p.
IdentifiersURN: urn:nbn:no:ntnu:diva-25545Local ID: ntnudaim:10835OAI: oai:DiVA.org:ntnu-25545DiVA: diva2:736507
Golan, Michael, Professor