As the quest to find new sources of oil and gas takes operators farther and deeper offshore into harsher environments, so does the need for technologies capable of withstanding higher temperatures and pressures.

When it comes to subsea operations and insulation technology, guarding against problems such as cracking and joint separation is a must. Developers of silicone rubber insulation technology believe the material is a good fit, particularly for HP/HT equipment used in deepwater production and for tiebacks.

Silicone rubber has been billed as a material capable of withstanding both high and low temperatures and being resistant to solvents, oil and other chemicals. It is known to have thermal conductivity that is better than other rubbers and to be highly adhesive.

Dow Oil & Gas Co. subsidiary Dow Corning developed a solid, non-syntactic silicone rubber system for subsea flow assurance applications. Called XTI-1003, the silicone rubber insulation is suitable for use on equipment such as wellheads, subsea trees, pipeline end manifolds and terminations, jumpers, flowline and rise ends, and flange connections—to name a few.

The technology came in response to industry needs, according to Brian Swanton, an industry specialist in silicone elastomer for Dow Corning. And it could help optimize flow assurance.

“The oil industry is looking for higher temperature insulation materials, alternatives in the market, which can go up to 200 C [392 F],” Swanton told SEN earlier this month. “Silicones are naturally very good at thermal insulation. They’re very good hot, so it was a natural fit to have silicone in this type of application.”

Swanton called XTI-1003 a relatively simple solution, considering it is cast similarly to polyurethane or glass syntactic polyurethane.

“The mix ratios are similar,” Swanton said. “The processing equipment is similar. The way you apply it is similar. The chemistry is different.”

The silicone rubber insulation system is not syntactic.

“This is a solid, so it really doesn’t have a limit to it,” when it comes to pressure, he added. “We’ve tested it up to 400 bar [5,802 psi] with no issues.”

As described by Dow, performance advantages include:

  • Thermal stability across a wide temperature range;
  • Good insulating properties for longer cooldown times;
  • Increased joint strength and high heat capacity; and
  • Long-term flexibility and resistance to extreme pressures.

The technology was cast as a core raw material for ExxonMobil affiliate Esso Exploration and Production Nigeria Ltd.’s Erha North subsea development offshore Nigeria.

“Subsea7 turned to Trelleborg Offshore’s advanced silicone insulation system, Vikotherm S1, which uses XTI-1003 RTV Silicone Rubber Insulation,” Dow said in article distributed during this year’s Offshore Technology Conference. The Vikotherm S1 system can effectively operate in depths of 3,000 m (9,842.5 ft) and in temperatures in excess of 135 C (275 F).

“On insulation projects that are completed or in progress, Vikotherm S1 is used on components such as tapered stress joints, manifolds, pipeline end terminations, pipeline end manifolds, vertical connection systems, and subsea pump stations,” Dow said.

When asked about any other new technologies in this area, Swanton said, “We’re always trying to get hotter. The temperature requirements are going hotter. They want easier to apply materials in general, [and] things that cost less. Those are all things that need to be worked on. Dow works on many different technologies, and we are working on new solutions.”

—Velda Addison

Offshore