EXPERIMENTAL INVESTIGATION OF SAND MINIMUM TRANSPORT VELOCITY IN MULTIPHASE FLUID FLOW IN PIPES
The production of reservoir fluid through long tiebacks/pipelines has emerged as one of the cost effective alternative especially for many marginal fields which can now be produced as clusters into a common processing facility. However, sand is often co-produced with the reservoir fluid especially when produced from unconsolidated formations. The sand will settle to form beds along the bottom of the pipe if the fluid velocity is below the minimum transport velocity required (MTV). In order to prevent solid deposition and ensure flow assurance, it is therefore critical to identify and measure the MTV. Two approaches are generally recognised for development of solid minimum transport velocity models in pipelines, the analytical and empirical methods. Because of the complexities of multiphase flow, the analytical approach will often require some assumptions and inputs from empirical measurement. This study presents the results of the experimental investigation for minimum transport velocity (MTV) both in suspension and rolling. The minimum transport velocity was found to be greatly influenced by the flow patterns and pipe inclinations. It was observed that the slug flow provides better solid carrying capacity in pipes when compared with other observed flow patterns. It was also observed that the influence of pipe inclination diminishes beyond 20⁰. The acquired experimental data will ultimately provide a comprehensive data base for testing and validations of analytical models for improved accuracy. The justification for experimental work was evident from the inconsistent and inaccurate results obtained using existing analytical models for MTV predictions.