Design of a Phase Change Insulating Jacket for Subsea Flowlines

Photo of Karla Johnson, Sonny Nguyen, Barret Pickett Students: Karla Johnson, Sonny Nguyen, Barret Pickett

Sponsor: Shell Global Solutions

Date: Spring 2011

Requirements:
One solution to the problem is incorporating phase change material (PCM) in the flowline insulation. For the PCM to be a viable solution the primary requirements include a phase change temperature above the hydrate formation, temperature to best prevent flow assurance problems, and a high latent heat to retain as much heat in the flowline as possible. Overall, the insulation design must keep the reservoir fluid above the desired arrival temperature and provide a sufficient cool down time during shut downs. Cost effectiveness and overall feasibility in terms of manufacturing and implementation are also major concerns.

Problem:
Deepwater petroleum production is quickly becoming a prevalent technique in the oil and gas industry as more local reservoirs are being depleted. To support this, a more innovative design for subsea flowlines is needed to provide the necessary thermal properties. Low thermal conductivity insulation is needed to keep the reservoir fluid above a critical temperature to avoid flow assurance issues. However, during shut downs for emergency situations, the fluid remains in a transient state without heat input from the reservoir. Deepwater flowlines that require shut downs are especially vulnerable to encountering line blocking issues, which can be both costly and dangerous.

Solution:
This project is a continuation of the Fall 2010 project. The project focuses on a heat transfer, feasibility, and economic analysis for nine design concepts that incorporate phase change material. An expanded study of the heat transfer algorithm written in MATLAB simulated the performance of each design under various subsea and reservoir conditions. Experimental testing analyzed the effectiveness of bulk PCM and microencapsulated PCM provided by Entropy Solutions Inc. Based on all the results and research, the team concluded that a design incorporating bulk PCM is the best solution. Bulk PCM provides the longest cool down time and represents the most efficient and straightforward design.

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Photo related to Design of a Phase Change Insulating Jacket for Subsea Flowlines project
Photo related to Design of a Phase Change Insulating Jacket for Subsea Flowlines project
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