ABSTRACT

After a production well completion has been installed, the completion fluids, consisting of a mix of brine and oil-based muds, are removed from the well tubing by displacing the completion fluids with the production reservoir fluids to the drilling rig. This exercise is costly in terms of the additional drilling rig time and the facilities required to process and safely dispose of the completion and production fluids. An alternative strategy is to produce the completion fluids back to the host production facilities directly, removing the requirement for drilling rig for well clean-up. This paper discusses the available strategies for well clean-up, the potential risks associated with clean-up operations (the compatibility of completion fluid properties, hydrate formation and large volumes liquids). The process simulation modelling methods are described as well as how the modelling output is used to define the operating strategies for minimisation of hydrate formation probability, for managing liquid surges, and for predicting the timing and concentrations of the completion fluids and associated chemicals arriving at the host platform to inform the requirements for temporary operating equipment. This paper also presents several case studies covering different types of completion fluids and the analysis and methods that were applied to simulate well clean-up to support the development of the operational and commissioning philosophies.