Effect of Sand Deposition in a Riser: Case Study of the Jubilee Field Riser

Abstract

Abstract Sand production is a common phenomenon in hydrocarbon extraction. It is the migration of formation sand as reservoir fluid flows, and can accumulate downhole around the production interval thereby blocking the production interval, and hence reducing production rate. The Jubilee Field experienced sand production during its early production stages. Although the challenge has been addressed through acidising, however, sand production is inevitable as the field matures. It is always desirable to have these sands flow through the riser to the surface. The flow conditions, the sand flow dynamics and the riser bathymetry could lead to sand deposition and accumulation in the riser. This study examines the flow dynamics and the effect of sand deposition on the flow integrity in a typical riser using computational fluid dynamics. It uses the Jubilee Field East Loop riser as a case study. It has been deduced that for the given flow conditions, there is the possibility of sand deposition and/or accumulation in some sections of the riser, and that low points in riser bathymetry are possible sources of onset for sand deposition. Sand dispersion decreases from the point of injection towards the lower region of the flow domain downstream from the injection point. Flow pressure and velocity were significantly affected by sand deposition and/or accumulation within the flow domain especially areas in the proximity of low points. The study established that uncontrolled deposition and/or accumulation of sand within these sections of the flow have the possibility of changing the flow characteristics within the riser. This study would aid in proposing effective strategies to mitigate the impacts of sand deposition in a riser. It will contribute significantly to the implementation of an effective pressure and sand management strategy.