The data gleaned from the repair shop gets fed into the company's in-house development and testing cycle. While examining cracked or fractured modules, Balmoral was able to ascertain the weaker spots of buoyancy modules and find ways to offset the weakness in those spots, such as integrating notched clamping areas. The repair business, originally not expected to be a focus for the company, has developed over the last couple of years, Brown said. So, the company established dedicated repair facilities in Houston and Macaé, Brazil. Modules that had been subjected to the deepwater rigors of GoM and South Atlantic currents were coming onshore in increasing numbers for repair. Assessing breaking pointsīalmoral recently identified an upturn in the drilling riser module repair business. Balmoral then checks the buoyancy lost, seeking less than a 3% loss per unit. The test simulates the target water depth at a designated pressure for 24 hours. ![]() The facility, which conduced its first trial in November 1999, can test three modules at a time and can accommodate a 21-ft piece. Once the buoyancy units are complete, 5-10% of the pieces take a 24-hour quality assurance dunking in the Hydrospace Test Center at Balmoral's Houston facility. When complete, the modules will head to Kværner's yard in Louisiana for dressing before meeting the rig for sea trials.īecause of the amount of time associated with the steel phase of constructing the buoyancy and riser string, it takes 30 to 40 weeks to create a full string. GSF already has strings for its Development Driller I and Development Driller II and recently ordered a third string as a backup for these two semis, formerly Rig 184 and Rig 185. Balmoral said it added UltraFloat's internal reinforcement system to increase the cracking and fracture resistance of the piece in addition to providing residual structural integrity of the piece should it break.īalmoral unveiled UltraFloat last year, and the buoyancy product has drawn support from Transocean and GlobalSantaFe. These breaks pose a safety hazard to personnel and could damage equipment if module sections become detached during running or pulling of the string. In some cases, extreme impacts or riser flexures will crack or fracture a buoyancy module. The system's composite reinforcement system was designed to enhance module stiffness while increasing flexure tolerance, according to the company. The units must also provide stiffness and flexural performance. UltraFloat's layer of epoxy composite protects the syntactic foam from this damage. Harsh operating conditions call for abrasion protection to reduce the effect of contact between the dressed riser string and the rig steelwork, Balmoral says. UltraFloat's buoyancy comes from a mix of syntactic foam, epoxy resin, hollow glass microspheres, and fiber-reinforced plastic minispheres. The damage-resistant nature of UltraFloat can mean overall reduced lifecycle costs for the units in addition to the increased safety aspect of the design. "We saw a large proportion of buoyancy units being damaged," he said.īrown calls UltraFloat the next generation of buoyancy and says it is tougher than previous systems and stands up better to harsh operating conditions. ![]() ![]() The traditional style of buoyancy is well suited to calm, shallow conditions, not for places like the Gulf of Mexico or off Brazil, where units have not only deeper water but also loop and eddy currents to contend with. "Traditional buoyancy has been made the same way for probably 20 years," said Gary Brown, president of Balmoral Group in Houston. Balmoral worked up the concept for UltraFloat to strengthen buoyancy units while reducing the weight associated with longer riser strings in response to drilling contractor requests to improve buoyancy module safety levels. The increasing operating depth is what led Balmoral to create the UltraFloat drilling riser buoyancy system. Balmoral Group took its observations about buoyancy needs, added what it found lacking in broken modules that entered its repair yard, and molded these findings into the UltraFloat and, later, RetroFloat buoyancy systems.īuoyancy providers found various issues cropped up as fields went deeper.
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