Water-Based Insulating Fluids for Deepwater Riser Applications

Abstract

Uncontrolled heat transfer from production tubing to outer annulus-especially in deepwater riser sections-can cause the deposition of sludge, paraffin, and asphaltene materials; contribute to the formation of gas hydrates; and limit shut-in time for unplanned downtime or remedial operations. Generally, deepwater risers can be insulated externally or insulated by placing nitrogen gas into the riser annulus. In recent years, a new water-based thermalinsulating fluid system has been developed and used in field applications. This new system reduces convection and provides a rheological profile to facilitate fluid placement into the riser annulus. This system has been successfully used in deepwater risers in the Gulf of Mexico (GOM).Laboratory-scale equipment and a full-scale test well were constructed to evaluate the thermal-insulation properties of fluids. This paper details the testing procedures and methods. Steady-state heat-transfer-and cool-down-test results on the new insulation fluid were determined and compared to conventional fluids. These superinsulating fluids were found to be vastly superior to brine and measurably better than conventional water-based insulating fluids. Surprisingly, when compared to nitrogen (air) or argon, the superinsulating fluids provided enhanced protection during cool down. Field cases in the GOM are summarized to demonstrate the effectiveness of this fluid system.

New Trend in Oilfield Flow-Assurance Management: A Review of Thermal Insulating Fluids

“…Most recently, specialized thermal-insulating fluid systems have been developed to control potential flow problems in the wellbore, riser, or export pipeline, which prevent the formation and deposition of gas hydrate, paraffin, and asphaltene materials through undesired heat loss from production tubing Javora et al 2006;Javora et al 2005;Wang et al 2006). This paper will highlight the evolution of different insulating fluid systems.…”