Progress Update: Effects of High Oil Viscosity on Slug Liquid Holdup
February 26, 2010
Effects of high oil viscosity on multiphase flow behavior have been experimentally studied by Gokcal (2005, 2008) at TUFFP. This is a continuation study of the high oil viscosity effect on flow behavior. In recent years, because of the increased consumption of hydrocarbon resources and decline in discoveries of conventional oils, the importance of the heavy oil has increased. Gokcal observed slug flow as the dominant flow pattern for the gas-liquid flow with high viscosity oil. He also reported significant differences in slug characteristics of high viscosity oils compared with those of low viscosity oils. Slug liquid holdup is crucial for the calculation of pressure drop and thus for the design of production and transportation systems. The main objective of the present study is to investigate the slug liquid holdup for high viscosity oil and gas flows and develop a better slug liquid holdup closure relationship.
One of the challenges of this project is to acquire accurate slug liquid holdup data. Since the last Advisory Board meeting, slug liquid holdup and liquid film height data have been collected with quick closing valve system. 150 tests were completed for 70 and 80 °F oil temperatures corresponding to 0.587 and 0.374 Pa•s oil viscosities. In Spring 2010, the remaining experiments will be carried out for 80, 90 and 100 °F oil temperatures. Differential pressure sensor with flush diaphragm pressure transducer was tested in order to measure differential pressure drop across the pipe. Unfortunately, the response of the differential pressure sensor was not satisfactory. Recently, a new capacitance sensor developed in-house has been placed to the test section and tested. Preliminary results are promising for slug liquid holdup measurement. The calibration of the capacitance sensor is currently underway. A detailed report will be presented at the Spring 2010 Advisory Board meeting. The experimental results will be compared with available slug liquid holdup correlations. If necessary, a new correlation will be developed.