Passive Slug Attenuation Device: Potential and Operability

Abstract

Over the years, there have been some concerted efforts towards developing techniques to mitigate the threat posed by slugs to oil and gas production systems. Passive slug attenuation devices have been known to show promising potential in this regard but can generally be confronted with operability issues. In this study, experimental investigation on the hydrodynamic slug attenuation potential and the operability of a process-intensified passive slug control device-Pseudo Spiral Tube (PST) was carried out. The result showed that the device possesses the capability to partially attenuate slug flow. This was achieved with the help of the swirl flow generated within the device which helps achieve air entrainments in the liquid slug leading to reduction in the effective density of the liquid slug. The results showed that the slug severity was reduced by 24% for the case studied. However, the slug redeveloped few meters downstream the device. Therefore, in order to achieve maximum slug attenuation, the device should be installed immediately upstream the topside separator. It was also observed that the pipeline might be pigged with the device installed. However, during multiphase flows, the pig may get stuck intermittently in the device. Hence, it was conceived that a flexible pig could be more appropriate to overcome this challenge.