Foam Wrap compensates for subsea well annular pressure.

Press Release Summary:

Typically installed within B or C annuli of subsea wells, CFW+ (Crushable Foam Wrap) acts as mechanical fuse and collapses at pre-determined pressure and temperature (110ºC) envelope. This allows expansion of annulus fluids as well as dissipation of any potentially hazardous increase in pressure. By incorporating Glass Bubbles, solution helps mitigate subsea well casing failure due to annular pressure build-up or trapped annular pressure.

Original Press Release:

Trelleborg Launches Enhanced Solution for Subsea Well Annular Pressure Incorporating 3M Glass Bubbles

1st October, 2008, Bracknell, UK: Trelleborg CRP - part of the $4.2Bn 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'. More from

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°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", continues 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.

3M is a registered trademark of 3M

Background Information

System Design
Trelleborg CRP is the market leader and 'the' expert in the manufacture of Syntactic foam systems for use in Subsea applications, with over 25 years track record. CRP Group was the first to develop syntactic foams for use in subsea drilling applications in the early 1990s.

Trelleborg CFW is a polymeric material which has a honeycomb micro structure allowing for compression and ultimately collapse of the system to take place. Trelleborg uses more than 10 grades of 3M Glass Bubbles with crush strengths ranging from 250 psi to 18,000 psi in combination with its resin to create a bespoke formulation and structure tailored to fail at the required pressure/temperature combination as dictated by the well conditions. Normally a pressure envelope of +/-1000psi at a fixed temperature is possible.

CFW is supplied in quadrant cylinders typically one metre long. This allows it to be handled and installed with ease and located anywhere within the trapped annulus while still allowing the free flow of the liquid. The quadrants are installed using a high performance acrylic adhesive.

The amount of CFW specified for a project is dictated by the 'Collapse Volume' and 'Crush Percentage' requirements within the annulus. The collapse volume is specified by the client and is defined as the calculated volume increase of the annulus fluid brought about by thermal expansion between the installation (or ambient) temperature and the operating temperature. The crush percentage is defined as the amount of compression under isostatic load the foam will allow before catastrophic collapse. This value is usually between 30 - 50% depending on the particular foam formulation. From the collapse value and crush percentage, a total volume of foam required may be calculated. Safety factors are employed during this design stage ensuring target criteria are always reached.

In the drilling start-up phase, the CFW remains in situ, with no significant volume change unless temperature increases beyond the collapse criteria.

As the pressure and temperature in the well rise during operations, the voids within the CFW begin to collapse and relieve pressure in the narrow, confined space of the annulus.

The crush mechanism is progressive in nature over the pressure envelope, but complete failure occurs well before the casing collapse pressure. Typically Trelleborg likes to see the minimum collapse pressure at least 1.5 times the max installation pressure.

About 3M
3M is a $24.5 billion diversified technology company which, since 1902, has been creating innovative products that help make the world healthier, safer and more productive. Well known 3M brands include Scotch, Post-it, Scotchgard, Thinsulate and Scotch-Brite.

3M employs 76,200 people worldwide, producing thousands of innovative products for customers in dozens of diverse markets in some 200 countries. Its 45 technology platforms touch nearly every aspect of modern life - the company has applied its expertise in RFID technology to deliver biometric passports; it is using its understanding of the healthcare industry to provide hospitals with infection prevention and detection solutions; and its digital signage offerings are revolutionising the way businesses communicate with their customers, their employees and the general public.

The UK and Ireland is home to one of the largest 3M subsidiaries outside the USA, employing 4000 people across 18 locations, including 12 manufacturing sites. Products manufactured in the UK include coated abrasives, occupational health and environmental safety equipment, adhesive tapes, industrial microbiology products, drug delivery systems, high-performance coatings, secure documents and passport scanners.

3M's involvement in the Oil and Gas industry
For more than 50 years, 3M has been meeting the evolving needs of the Oil and Gas industry. Globally, the company supplies some 10,000 products that are used in all aspects of the industry, from exploration, production and refining through to transportation and retail.

In the UK, 3M's Oil and Gas business has a team of highly experienced specialists, based both in Aberdeen and at our head office in Bracknell, Berkshire. Their role is to focus on the specific requirements of our UK-based customers. However, while our presence is local, our resources are global. 3M employs some 6,500 researchers and, with laboratories in 35 countries, we have the means to meet the industry's toughest challenges.

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