"Coupled with the two wells drilled earlier this year using DUCT technology, this particular operation for NAM is very important, especially in terms of BJ Services' plans to effectively export this exciting technology globally," said Alasdair Buchanan, BJ Services region manager – Europe & Africa, Well Services Division. "DUCT is especially significant to the industry because we can deploy the BHA under pressure in a safe, efficient manner, which is critical when drilling underbalanced, and especially so when drilling underbalanced in the presence of H2S gas," he added.
Building on Success
More than 260 DUCT projects have been completed in Canada by BJ Services. The three operations in Holland carried out in 2003 mark the first comprehensive international application of the technology.
Previously, BJ successfully drilled two onshore wells in the Coevorden Field in the Netherlands using DUCT technology on behalf of NAM. A team of about 70 individuals from five countries teamed up to drill wells Coevorden 16 and 17b. The project entailed drilling a 1,650-foot (500 meter) horizontal section in a naturally fractured carbonate formation with a bottom-hole pressure of 4,800 psi and temperature of 220°F (104°C). Bottom-hole assemblies (BHA) and hands-free pressure deployment technology were provided by BJ Services Company Canada, with CT drilling engineers, project management personnel and deployment and BHA specialists.
BJ's base in Emmen, Netherlands, provided the CT drilling unit, mast structure, pump systems, and the operational team to run both the CT and pumping equipment. Work reels suitable for the CT length (14,435 feet/4,400 meters) and size (2-3/8-inch) were mobilized to location with a 10,000-psi blowout preventer. Crews from Canada and the Netherlands drilled the wells underbalanced using KC1 brine and nitrogen.
Natural gas production commenced shortly after drilling into the first fracture system on Coevorden 17b, and increased with each subsequent natural fracture encountered. The decision was made to terminate drilling after 580 feet (176 meters). Drilling and deployment operations were performed with high surface gas rates and wellhead pressures of 4,000 psi.
Two lateral sections were drilled for the second well. One extended 1,729 feet (524 meters) and the other 1,128 feet (342 meters). The well flowed gas during drilling and deployment and contained 500 – 1,500 parts per million of sour gas. All operations were performed in a live well environment with returns handled by The Expro Group.
The 52-day operation was flawlessly managed with a total 3,458 feet (1,048 meters) drilled. "All BJ personnel attached to the project provided professional input and support. However, Bob Fraser, BJ team leader for coiled tubing drilling engineering, and Ken Hall, BJ/NAM senior project engineer, were cited by NAM as providing notable contributions to the success of the project," said Jim MacArthur, business development manager for BJ global coiled tubing drilling. "Overall project management was conducted in-house by NAM."
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