Performance improvement of Gas-Liquid Cylindrical Cyclone separator using different design for tangential inlet

Abstract

The concept of compact separation is attractive in a number of operating environments. These include offshore and arctic operations, where both space and weight are at a premium, and downhole processing where space is very limited. Compact separators often rely on centrifugal forces to enhance the separation process and are therefore highly dependent on inlet geometry. This paper investigates expanding the operational envelope of a compact Gas-Liquid Cylindrical Cyclone separator through the use of a novel inlet, which can be easily altered to respond to changing well conditions. To demonstrate the importance of inlet geometry, historical production from the Gloyd-Mitchell zone of the Rodessa Field in Louisiana was examined over a 40-month period. As in most oil field production, there were significant changes in the water cut and GOR. This field data clearly shows that a compact separator equipped with single inlet geometry is not capable of performing effectively over the wide range of conditions exhibited in a typical oil field. This thesis considers the hydrodynamics of the separator inlet. Three different inlet geometries were investigated through the use of a changeable inlet sleeve. New experimental data were acquired utilizing a 7.62-cm I.D compact separator, which was 3.0 m in height. The effect of inlet geometry on separator performance was investigated over a wide range of flow conditions. Fluid viscosities from 1-12 cp and the effect of fluid level within the separator were also examined. The results indicate that the operational envelope for liquid carry-over and gas carry-under can be expanded by more that 300% by altering the inlet to respond to changing field conditions. A new model is proposed to define the operational envelope. This approximate method is simple to calculate, and offers a good approximation for the operability area for gas-liquid cylindrical cyclone compact separator. This study shows that efficient operability of the gas-liquid cylindrical cyclone is obtained when tangential acceleration of the incoming gas-liquid mixture is 50 to100 times the acceleration of gravity (50-100 G's).