VetcoGray´s Metal-to-Metal Sealing Technology

The increase in exploratory O&G programs around the world and specifically the deepwater exploration programs being undertaken at the GOM, in West Africa and Brazil has caused major improvements and new technologies and materials to be employed in subsea equipment, such as BOPs, wellhead systems, risers, manifolds, flowlines, drilling fluids among others. GE´s VetcoGray has developed an interesting seal technology for its subsea wellheads. Named MS seal, it is based on Metal-to-metal sealing technology.

All VetcoGray subsea wellheads use metal-to-metal sealing technology, which is superior to elastomer options because it prevents inevitable heat and corrosive fluids from damaging seal integrity. Both the wellhead and hanger have a sealing area of parallel wickers. Once the seal is properly installed these wickers act as both the sealing and locking mechanism. The seal is installed with a combination of weight and pressure, pushing the energizing ring between the metal “U” seal and expanding it into the wicker profiles. This “U” seal expansion forces the wickers into the softer seal metal creating a reliable seal even if the wickers have been damaged.

There are a few methods based on the Metal-to-Metal technology being used for sealing. The first is the MS-E which is installed via the running tool in the same manner as the MS-1. The only difference between the MS-E and the MS-1 is the soft binary alloy. The binary alloy allows for softer material to flow into damaged areas. Another option is the SG-TPR. The SG-TPR includes an elastomer and metal sealing combination that seals below the wicker area.

The novel MS seal system is employed on all of VetcoGrey´s MS-700 wellhead system.

The MS-700 technology offers high flexibility in terms of casing programs and is designed to help O&G operators working in ultra-deep water reservoirs increase their efficiently, decreasing overall E&P costs and also saving money by needing less rig time over the wells.

Recently  GE O&G has signed a three-year frame agreement valued at approximately $30 million to supply 26 subsea wellhead systems and associated services to Shell Brasil Ltda. for exploration and production projects offshore Brazil. The agreement means GE Oil & Gas will supply all Shell Brasil's requirements for subsea drilling systems for all offshore exploratory and development wells to be drilled by Shell Brasil at least until the end of 2013.

Under the agreement, GE will supply 13 MS-700 Slimbore and 13 MS-700 deepwater high capacity (DWHC) systems. According to GE, the MS-700 is the only subsea wellhead system on the market with metal-to-metal sealing, and has demonstrated high reliability for projects offshore Brazil, being one of the preferred systems for deepwater wellheads.

Another important aspect is that most of the equipment will be manufactured at GE's manufacturing plant in Jandira, São Paulo State, Brazil with deliveries to begin in Spetember 2011. The importance of building the equipment in Brazil, is related to the Brazilian local content laws that demand a high percentage of local content also in equipment manufacture. This may be an important trump card for GE, as they are one of the few heavy subsea equipment manufacturers with local manufacturing facilities installed and this fact should definitely help them in attracting more orders from local and foreign O&G operators, including Brazil´s Petrobras, which is highly commited to deepwater exploration in Brazil and abroad.

Claudio Paschoa