Separation Performance of Compact Axial Hydrocyclone for Water Pre-separation from Wellstream

Abstract

Abstract Efficient and compact separation technology is in urgent need for many oilfield exploitations because of increasing water cut and strict discharge regulations. A compact axial hydrocyclone is presented to pre-separate water from the wellstream. Experimental investigation was carried out to qualify its performance. A test loop is designed to perform experimental investigations. The flow loop is fabricated to manipulate and control various operational variables, such as the oil/water mixture flow rate (0.5-2 m3/h), the oil droplet size, and the water-to-oil ratio (65/35 to 100/0). A combination of venturi tube and static mixer is used to mix oil/water mixture. Dehydration rate and oil concentration at water outlet are used to evaluate the oil/water separation performance. A series of experiments have been carried out to test the performance of the novel hydrocyclone. Inlet parameters, including inlet flow rate, water cut, droplet size and split ratio, have been evaluated. Inlet flow rate, water cut, and droplet size have significant effects on the separation performance. When the oil concentration in the water outlet is controlled to be less than 1,000 ppm, a maximum dehydration rate of 70% can be obtained. The compact axial hydrocyclone exhibits high separation performance and reliability for a wide range of operating conditions. A stable oil core without vortex oscillations is observed. This effect, combined with the low pressure drop, indicates a stable swirl with low turbulence, which enables a higher capacity of the compact axial hydrocyclone compared to traditional hydrocyclone.