With wellbores drilled in ever deeper waters penetrating further into the earth and clients demanding improved performance from all parts of the drilling process, VAM Drilling has focused on two aspects of the drillstem it believes deliver on the reliability front. Jennifer Pallanich finds out more about the company's tool joint connection and a drillstem member for hole cleaning.
VAM Express has a higher torsional efficiency than API connection requirements, allowing a slimmer tool joint than other connections. The benefit is that a large drill pipie may be used for strength and optimum hydraulics while retaining the same tool joint OD, and the connection runs as easily as an API connection, says Laurent Bordet, regional technical support manager covering Europe, CIS, Africa and the North Sea for VAM Drilling.
The tool was used in the Devon-operated Polvo project offshore Brazil. Devon is in the process of selling its interests in the field in 300ft of water in the Campos Basin to BP in a deal expected to wrap up this year. The field features both horizontal wells with relatively short reach and extended reach wells with deviation spans of 3°-7° dogleg severity at angles of 30°-92°. The Pol-O wellbore was drilled to 6489m MD (2429m TVD) and a vertical section step-out of 5615m. The project attained a record in 2007 for the fastest drilling of an 8 1/2in hole with 1610m drilled in 24 hours, VAM says, adding the record came from the high ROP and was aided by the reduced make-up time associated with using the VAM Express connection, compared to other high torque connections. The drill pipe avoided drillstring failure as no twist-offs or back-offs were observed.
The connection is designed around a proprietary thread profile and a double shoulder design that makes it a hightorque performer, according to the company. The primary shoulder provides initial seal and pre-load during make-up while the secondary shoulder provides high-torque capability. The thread form features a large, rounded stab crest and a laid down stab flank for easy connection stabbing. VAM uses a back beveled crest to reduce the chance of wedging the thread; this also increases the freedom of movement. An elliptical root increases resistance to rotational-induced bending fatigue.
VAM Drilling has been using VAM Express in the Gulf of Mexico and North Sea as well as offshore Brazil, West Africa and Southeast Asia.
‘To do connections – that's in our DNA at Vallourec,' Dirk Bissel, managing director in VAM Drilling's drilling products division, says.
Sour focus
One issue in Brazil is troublesome H2S, and when steel is to be used in these sour environments, a unique steel chemistry and special heat treatment are necessary. Steel not designed for a sour environment, Bordet notes, can rapidly fail. VAM Drilling offers three grades of steel for sour environments: severe sour,medium sour and mild sour. HPHT issues also have their own requirements. ‘You need really clean steel,' Bissel says. ‘The rolling mill process has to be at a different level than anywhere else.'
VAM Drilling expects to be able to offer that level of clean steel through its new integrated facility in Brazil. Opening later this year next to the company's rolling mill in Belo Horizonte, Brazil, the new drilling mill displays what Bissel sees as a logical step in an ‘exciting' market. ‘It's a perfect fit for us,' he says, pointing out that VAM Drilling has been established in the country with the rolling mill since 1954.
The new facility, to be staffed through 100% local content, will assemble drill pipe, risers and landing strings. The mill will create up to 70 jobs and was scheduled to begin its first job manufacturing drill pipe in April for delivery in July for an international offshore drilling contractor.
‘The motivation why we're there is clear,' Bissel says. ‘We are very much committed to Brazil and South America.' The Brazilian operations, he noted, mirror VAM Drilling's set ups in other areas, including the Middle East, Europe and the Gulf of Mexico. The key, Bissel notes, is to be close to the clients. In fact, VAM Drilling is also opening up a client support center along Houston's Energy Corridor later this year so that it can better learn a customer's future needs. A staff of 20 will spearhead the company's endeavor to ‘be a bit in front of the next wave' in demands, Bissel says. ‘We're putting a big effort into Houston' because the company believes up to 70% of engineering decisions in the oil & gas industry are made in Houston.
As Bordet puts it, Houston ‘is a decision center.'
One of VAM's selling points, Bissel says, is that the company owns its own forge to make tool joints. ‘The idea is to be fully integrated.' This is becoming increasingly important as customers want to know more about the products they use, he adds. Bissel, with his background in the automotive industry, believes traceability will become a larger focus over the upcoming years. ‘It's not good enough to prove through a few samples that you can do it. At VAM, we don't need to talk to suppliers on this. We just need to manage ourselves.'
Hole cleaning
Keeping the wellbore clean can help reduce operating costs and NPT. Bissel says VAM Drilling designs hole cleaning plans with the company's clients so the Hydroclean Drill Pipe and Heavy Weight Drill Pipe tools perform correctly. Bordet says having access to the well profile, mud type, hydraulics, casing program and other pertinent information makes it possible to calculate what is needed from the tool. ‘This is where tools like simulation really kick in,' Bissel says.
The tool was designed to reduce wiper trips, backreaming and viscous mud sweeps. It has shown up to 60% improvement in hole-cleaning efficiency compared to offset wells and up to 30% reduction in torque and drag loads, according to Bordet, and has reduced pressure losses by over 50%, the company says. The performance is down to a design in which the upsets have blades in which the combination of rotational speed, flow rate and the blade's angles produce certain mechanical and hydrodynamic effects. These effects, according to VAM Drilling, increase the quantity of cuttings reintroduced into the flowstream. The bearing section has a slightly larger OD, which protects against borewall damage while protecting the blades.
The Hydroclean drill pipe and heavy weight drill pipe have been used in the Gulf of Mexico and the North Sea. One outing was at ExxonMobil's Ringhorne field in the North Sea, and was deployed by KCA Deutag. The company had experienced drilling problems related to a highly deviated well, and required hole cleaning and torque reduction in the 17 1/2in well section. Thirty joints of 6in OD Hydroclean drill pipe was mobilized. The well began producing in February 2003. The Ringhorne project, situated 110 miles southwest of Stavanger inblocks 25/8, 25/10 and 25/11, involved drilling up to 24 wells by 2006 in 420ft of water. Peak production equaled more than 80,000b/d of oil and 28mmcf/d of natural gas. OE