Energy Policy Act of 2005 (Ultra-deepwater and Unconventional Resources Program)
Flow Phenomena in Jumpers- Relation to Hydrate Plugging Risk
The University of Tulsa, Tulsa, OK 74104-3189
In deepwater and ultra-deepwater systems, hydrate formation and plugging is the number one concern because of the difficulty to remediate hydrate plugs and the associated lost production costs. Design solutions such as flow line insulation and inhibitor injection - such as methanol - constitute the standard engineering methods deployed to avoid hydrate formation and plugging. Restart scenario and profiles are evaluated using state-of-the-art transient flow models. Despite very conservative standards and operating strategies, plug formation is still not completely avoided, and the production jumpers seem to be at a higher risk during restart operations, in part because of their geometry, the difficulty to insulate such geometries and a probable misunderstanding of the complex flow patterns and phenomena taking place in the jumper during restart. Once a plug is formed in a jumper, current jumper designs make it difficult to remediate the plugs, leading to very large remediation costs.
This project proposes to utilize the know-how and infrastructure available at the University of Tulsa Hydrate research project to improve the understanding of liquid displacement and flow pattern in jumper-like systems during restart operations. Previous research at TU has shown the importance of the presence of a free-water phase and its displacement on the plugging tendency of a system.
The project will study the displacement of the oil and water phases during restart in a jumper configuration and comparisons will be made with existing transient simulators to validate transient flow models. Effects of liquid loadings, water loadings and restart rates will be studied on the displacement of the water phase. From this work, improved restart strategies to avoid plugging with a free water phase in a jumper may be developed, and confidence in existing prediction models improved. Additionally, data collected from this project may lead to better prevention methods, such as better methods to displace water out of a non-inhibited jumper while avoiding plug formation. Inhibitor distribution and displacement can also be studied in this facility, which may lead to better design of injection points in jumpers.
Principal Investigator Dr. Michael Volk, Jr