Trelleborg Unveils Enhanced Solution for Subsea Well Annular Pressure

Trelleborg AB Group

Trelleborg CRP, part of the $4.2 billion Swedish Trelleborg AB Group, has announced the development of CFW+, a new high pressure, high temperature crushable foam wrap incorporating Glass Bubbles from 3M, the diversified technology company. CFW+ provides an enhanced solution for the mitigation of subsea well casing failure due to 'Annular Pressure Build-up,' or 'Trapped Annular Pressure.'

Says Guy Downie, Manager Subsea Group, Trelleborg CRP, "Our Crushable Foam Wrap (CFW) is typically installed within the B or C annuli of subsea wells, displacing the liquid which becomes trapped in the casing annulus when subsea wells are completed. When heat from drilling and production operations causes the trapped liquids to expand -- creating Annular Pressure Build-up (APB) which can exceed 10,000psi -- our CFW acts as a mechanical fuse and collapses at a pre-determined pressure and temperature envelope to allow expansion of the annulus fluids and dissipation of any potentially hazardous increase in pressure. If not managed, APB-induced loads can compromise well integrity, potentially leading to leaking fluids or catastrophic collapse of the well casing, halting production.

"Until now, the operating range of our CFW solution has had typical performance in excess of 4000psi 60-80 degrees C, which has been sufficient to meet the needs of such projects as the 21 well installation we have just completed offshore Nigeria. However, due to trends in drilling more complex wells, sometimes much deeper and further offshore, we have developed CFW+ which can provide an APB solution for these more demanding situations to temperatures in excess of 110ºC and much greater pressures."

The operating range of CFW+ has been enhanced due to the modification of the resin system in combination with a range of 3M Glass Bubbles. Trelleborg's laboratories developed this improved resin, which is also more resistant to water absorption, allowing greater lifetime downhole before utilisation. 3M Glass Bubbles were selected due to their consistency and quality, which contribute to the reliability of the end product.

"As a result," continued Guy Downie, "Trelleborg manufactures a bespoke CFW+ formulation designed to match the required collapse volume and pressure collapse range specified by drilling and completion engineers for the more demanding deep subsea APB mitigation solutions. This is the only commercially available solution to operate on Temperature and Pressure triggers, rather than just pressure alone."

Trelleborg has developed this extended range of syntactic foams to assist operators in the busy drilling operations schedule, with potential use on over 100 developments between 2009-2011.