Slugging in pipeline-riser systems is becoming more common as the petroleum industry matures. Current trends of developing deepwater fields and producing from marginal fields via subsea tie-backs to existing facilities often lead to slugging. Slugging also occurs in fields approaching end of life, due to decreased gas coupled with increased water productions. Slugging is a major problem for offshore operations because it causes large fluctuations in gas and liquid production which may cause platform trips and riser vibrations. These will lead to production deferment, riser integrity/safety issue, and potential abandonment for fields operating near end of life.The most recent slug control technology in Shell is the Smart Choke. This technology utilizes a single control valve which is installed between the riser top and first stage separator. It is an active slug control device which regulates liquid and gas flow by manipulating the control valve opening. Compared to conventional slug management techniques which require large footprints and high capital/operating costs, Smart Choke is compact and cost-efficient.Smart Chokes have been installed in the Gulf of Mexico, Nigeria and Malaysia. The pipelines had large fluctuations in pressure and gas/liquid flowrates due to hydraulically unstable flowline/riser system. The installed Smart Chokes were tested to be effective in suppressing riser-induced slugs and controlling slugs initiated within horizontal pipelines. Deployments to-date has shown for example field life extensions of over one year or production gains of about 5 to 10%. This paper presents the implementation of Smart Choke from feasibility study to site implementation in a Malaysian field. It is the first project that integrates Smart Choke control into a platform control system for easier operation. Field data are presented to demonstrate how Smart Choke has extended the field life through the control of slugs. As a result, the shut-in field which was planned for abandonment could continue production.

Description Large fluctuations in gas and/or liquid production can lead to major disruptions on the topside facilities. These fluctuations are caused by the fluid composition, geometrical layout and operating conditions of the production system. With the current trends of: Producing marginal gas/condensate and oil fields to existing facilities with subsea tie-backs, Developing more deepwater fields, Producing from existing production facilities towards the end of field life cycle, irregular production or slugging pipeline systems are observed more frequently. Therefore, slug mitigation techniques may achieve significant value impact on the business. The most recent technology in Shell for slug control is the Smart Choke. This technology consists of a single control valve that is installed between the riser top and the first stage separator. It is an active slug control device acting on gas and liquid surges without the requirement of phase separation upstream of the control valve. The basic control mechanism maintains a constant total volumetric flow at the system outlet. Furthermore, a detection algorithm is incorporated, which detects 'liquid only' or 'gas only' production. Based on this, the controller will switch between the different control modes for slug control. Additional to this flow controller, a slow valve position controller and a differential pressure override controller is used to ensure that the output of the volumetric flow controller remains in the range of the normal (or desired) operating valve position.