Topside Pipeline Design for Slug Attenuation and Increased Oil Production
In oil and gas production system, slugging is frequently encountered when gas-liquid mixtures are transported through a common pipeline-riser system. This phenomenon usually manifests in significant fluctuation of flow and pressure which can impact the production system negatively. Topside choking is usually employed as a mitigation technique but with its attendant reduction in production capacity. The objective of this study therefore is to investigate the optimisation of topside pipeline diameter and choking for effective slug attenuation and optimised oil production. In this paper, a new method for slug flow attenuation has been proposed. The potential of using effective topside pipelinediameter design for slug flow attenuation was theoretically shown. Numerical studies were also done to show that the concept can indeed be adapted for effective slug attenuation using an industrial software. Experimental studies were conducted in a 4” pipeline-riser system to validate the numerical and theoretical studies.The results showed that the optimised design of topside pipe diameter has potential for slug flow attenuation at larger valve opening which effectively translates to lower pressure and increased oil production. For the case studied, up to 49% reduction in the pressure drop across the topside choke valve was reported which practically implied increased flow capacity. An optimum volume which satisfied size, system stability and production constraints was obtained.